TRANSACTIONS

OF THE

AMERICAN INSTITUTE OF MINING
AND METALLURGICAL ENGINEERS

(INCOHPO RATED)
WITH WHICH IS CONSOLIDATED THE

AMERICAN INSTITUTE OP METALS

.VOL. LXV

CONTAINING PAPERS AND DISCUSSIONS ON PETROLEUM AND GAS

NEW YORK, N. Y.
PUBLISHED BY THE INSTITUTE

AT THE OFFICE OF THE SECRETARY
29 WEST 39TH STREET

1921

AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS
[INCORPORATED] .

FBKNH TO.K FA

Bancroft Library

**&+ PREFACE

In this volume are the papers and discussions on Petroleum and
Gas that were presented at the Chicago meeting, September, 1919, the
Lake Superior and St. Louis meetings, August and September, 1920,
the New York meetings of 1920 and 1921, and the Wilkes-Barre meeting,
September, 1921; also proceedings of the St. Louis meeting.

CM
0>

VI CONTENTS

PAGE

Variation in Decline Curves of Various Oil Pools. By R. H. JOHNSON (With

Discussion) 365

Application of Taxation Regulations to Oil and Gas Properties. By THOMAS Cox

(With Discussion) 374

Valuation Factors in Casing-head Gas Industry. By O. U. BRADLEY (With Dis-
cussion) 395

Modified Oil-well Depletion Curves. By ARTHUR KNAPP (With Discussion) ... 405
Barrel-day Values. By G. H. ALVEY and A. W. FOSTER (With Discussion) . . 412
Isostatic Adjustments on a Minor Scale, in their Relation to Oil Domes. By M.

A.LBERTSON 418

Anthony F. Lucas Biographical Notice. By H. B. GOODRICH 421

Rock Classification from the Oil-driller's Standpoint. By ARTHUR KNAPP. . . . 424
Investigations Concerning Oil-water Emulsion. By A. W. McCoY, H. R.

SHIDEL and E. A. TRACER (With Discussion) 430

Drilling and Production Technique in the Baku Oil Fields. By ARTHUR KNAPP

(With Discussion) 459

Determination of Pore Space of Oil and Gas Sands. By A. F. MELCHER (With

Discussion) 469

Water Displacement in Oil and Gas Sands. By R. H. JOHNSON (With Dis-
cussion) 498

Composition of Petroleum and its Relation to Industrial Use. By C. F. MABERY

(With Discussion) 505

Carbon Ratios of Coals in West Virginia Oil Fields. By DAVID B. REGER (With

Discussion) 522

General Notes on the Production, Marine Transportation and Taxation of

Mexican Petroleums. By V. R. GARFIAS 528

Efficiency in Use of Oil as Fuel. By W. N. BEST (With Discussion) 568

PROCEEDINGS OF THE ST. LOUIS MEETING vii

Petroleum and Gas Meeting at St. Louis

A SPECIAL meeting arranged by the Petroleum and Gas Committee
of the American Institute of Mining and Metallurgical Engineers was
held on Tuesday and Wednesday, Sept. 21 and 22, 1920, in the Assembly
Room of the American Annex Hotel, St. Louis, Mo. Those in attendance
were guests of the St. Louis Local Section.

Preceding the first session on Tuesday morning, the members and
guests were registered and presented with the usual Institute badges.
The morning session was opened at 10:30 by Ralph Arnold of Los Angeles,
Calif., chairman of the Petroleum and Gas Committee. In his opening
remarks, he suggested that the petroleum section specialize more and
more on the technical problems of the oil industry and that an effort be
made to enlarge the membership of the Institute among the technical
men of the industry. The following program was presented:

Oil Fields of Russia, by A. Beeby Thompson and.T. G. Madgwick, of London,
England. Presented by H. A. Wheeler; discussed by Arthur Knapp and R. Van A.
Mills.

This most comprehensive paper was one of what is hoped to be a
series to be presented by some of our foreign members. It is by far the
best description in English of the world-famous Baku and other fields of
Russia.

Extended Life of Wells Due to Rise in Price of Oil, by WiUard W. Cutler, Jr., of
Chevy Chase, Md. Presented by the author; discussed by J. L. Darnell.

This paper brought graphically before the audience the fact that the
economic life of a well lengthens as the price of oil goes up.

Urgency for Deeper Drilling on the Gulf Coast, by A. F. Lucas, of Washington,
D. C. Presented by Mowry Bates; discussed by David White, W. E. Pratt, Mo wry
Bates, R. Van A. Mills, J. L. Henning, Arthur Knapp and E. DeGolyer.

. This paper opened up the always interesting subject of salt domes on
the Gulf Coast and the possibility of the occurrence of oil at great depth
in these structures.

Petroleum Industry of Trinidad, by George A. Macready, of Los Angeles, Calif-
Presented by R. A. Conkling; discussed by Arthur Knapp, R. A. Conkling, E. De-
Golyer, Ralph Arnold and R. Van A. Mills.

Oil Shales and Petroleum Prospects in Brazil, by H. E. Williams, of Rio de Janeiro,
Brazil. Presented by J. Elmer Thomas; discussed by David White, Mowry Bates,
B. O. Mahaffy, J. Elmer Thomas and Ralph Arnold.

The latter paper brought out the point that there are possibilities of
developing oil from oil shales, and in addition that there are certain
localities along the eastern flanks of the Andes in Brazil that may
eventually yield commercial quantities of oil.

Viii PROCEEDINGS OF THE ST. LOUIS MEETING

TUESDAY AFTERNOON SESSION

The afternoon session was opened at 2.30 and was presided over by
Vice-chairman E. DeGolyer. The following papers were given:

Determination of Pore Space in Oil and Gas Sands, by A. F. Melcher of Washing-
ton, D. C. Presented by W. E. Pratt; discussed by R. Van A. Mills, Walter M.
Small, W. W. Cutler, Jr. and David White.

This paper brought out the point that there are other determining
factors affecting the oil saturation of rocks than the size and shape of
the grains.

Application of Taxation Regulations to Oil and Gas Properties, by Thomas Cox,
of Oakland, Calif. Presented by E. B. Hopkins; discussed by Ralph Arnold, J. L.
Henning and W. E. Pratt.

Oil Possibilities of Northern Alabama, by D. M. Semmes, of University, Ala.
Presented by Walter M. Small; discussed by David White and Mowry Bates.

Efficiency in Use of Oil and Gas as Fuel, by W. N. Best, of New York. Presented
by James H. Hance; discussed by S. O. Andros, H. P. Mueller, J. L. Henning, I. N.
Knapp, and C. H. Matthews.

Industrial Representation in the Standard Oil Co. of N. J., by C. J. Hicks, New
York. Presented by John L. Henning; discussed by Ralph Arnold, W. E. Pratt, and
Mr. Trowbridge.

Valuation Factors in Casinghead Gas Industry, by O. U. Bradley, Muskogee,
Okla. Presented by W. B. Wilson; discussed by W. E. Pratt, E. DeGolyer, J. L.
Henning, W. M. Small and Mr. Reeves.

Nature of Coal, by J. E. Hackford of London, England. Presented by David
White; discussed by Ralph Arnold, David White, W. E. Pratt and E. DeGolyer.

In the evening an informal smoker was given to the visiting members
and guests at the American Annex Hotel. Moving pictures were shown ;
some short speeches were given and suitable refreshments provided.
The evening was greatly enjoyed by those present.

WEDNESDAY SESSIONS

The Wednesday morning session was called to order at 10 o'clock
by Ralph Arnold, who presided. The following program was presented:

Analysis of Oil-field Water Problems, by A. W. Ambrose, Bartlesville, Okla.
Presented by C. E. Beecher; discussed by R. A. Conkling, R. Van A. Mills, E. De-
Golyer, Mr. Reilly and Mr. Compton.

Contribution of Oil Geology to Success in Drilling, by F. G. Clapp, of New York.
Presented by W. E. Wrather; discussed by E. DeGolyer.

Ultimate Source of Kentucky Crudes, by W. R. Jillson, of Frankfort, Ky. Pre-
sented by title, as manuscript was not received in time for preparing abstract.

Oil-field Brines, by C. W. Washburne of New York. Presented by Walter M.
Small; discussed by R. Van A. Mills, E. DeGolyer, W. M. Small, R. A. Conkling,
Mr. Reilly, W. E. Pratt and W. E. Wrather.

The last paper brought out further discussion regarding the theories
of origin of salt domes.

PROCEEDINGS OF THE ST. LOUIS MEETING IX

The above list completed the formal papers. Following the formal
meeting the ensuing papers were presented without discussion:

Gulf Cretaceous Oil Fields, by Julius Fohs. Presented by the author.
Oil Resources of Illinois, by Mr. Mylius, of Urbana, 111. Presented by the author.
Influence of Faults in the Illinois Fields, by H. A. Wheeler, of St. Louis, Mo.
Presented by the author.

Prior to the adjournment of the meeting a resolution was passed
extending the thanks of those present to the St. Louis Local Section for
its hospitality and for the courtesies extended during the meeting, with a
special vote of thanks to Dr. H. A. Wheeler for his untiring efforts in
making the meeting a success.

The afternoon of the twenty-second was spent in a trip to interesting
points about St. Louis, in automobiles provided by the St. Louis Section.

PAPERS

VOL. LXV. 1.

4 PETROLEUM RESOURCES OF GREAT BRITAIN

they could not remain in the government if such legislation was passed as
a government measure. The compromise reached was that a bill should
be passed declaring that no one could sink a test well for oil or gas in
Great Britain without a license from the government, and the question
of royalty and ownership would be dealt with after the war. The govern-
ment gave an undertaking to Parliament that it would not recognize the
payment of royalties on oil until Parliament had acted. This legisla-
tion was passed in October, 1918. The government then took the land
necessary for nine well sites (seven in Derbyshire and two in Stafford-
shire) under the powers given it by the Defence of the Realm Acts.
This gave the right of occupancy, but not of ownership. Later, two
additional sites were taken in Scotland; as one of these was taken after
the signing of the armistice the validity of the action is now the subject
of a lawsuit. The present condition is, therefore, that while the govern-
ment may still legally, for the time being, have the power to take sites
under the Defence of the Realm Acts, it cannot justify the expediency of
so doing; it cannot acquire such sites by agreement, because this would
involve the payment of a royalty to the landlord, or the recognition of his
ownership of the oil, and it cannot grant a license to anyone else because
this also would involve the same recognition indirectly.

The first well sunk by the government found commercial oil, and while
it would have been relatively easy to pass legislation giving the ownership
of the oil to the government when the majority of the landlords had no
belief in its existence, the laborites and extreme radicals have now been
furnished with the politically effective argument that the oil was found
with government money. Even the utilization of the oil found in the
test wells, which will be limited to the ones already started, is subject to
the serious handicap that whenever the government starts to remove the
oil from the tankage at the well site the landlord will immediately start
injunction proceedings.

FUTURE COMMERCIAL PROSPECTS

In the center of England the Mountain limestone (Mississippian) is
exposed along the axis of the Pennine fold. Like the similar carbonif-
erous limestones in Kentucky and Missouri, it is cut by spar and lead
veins, but unlike these, it contains numerous important seepages of
petroleum. The upper 100 to 150 ft. (30 to 45 m.) of this limestone is
dolomitic. Overlying the Mountain limestone are the Yoredale shales
and sandstones, which in the important area to the east have a thickness
of from 400 to 700 ft. (121 to 213 m.) and in the area to the west, 2000 to
2500 ft. The Yoredale shales are followed by the Millstone grits series
of shales and important porous sandstones with a total thickness on
the east of 700 to 900 ft., and on the west of about 300 ft.; these, in turn,

A. C. VEATCH 5

are succeeded by the productive coal measures. On each side of the
main Pennine fold, subsidiary folds produce a whole series of local domes,
anticlines, and terraces in the regions where the limestone is overlaid by
the Yoredale and succeeding rocks. There is considerable faulting, but
the character of the oil produced in the limestone is such that, while it is
of a paraffin base, it oxidizes even more rapidly than an asphaltic oil.
There are no surface exudations of oil of importance on either side of the
main limestone mass, but for the last century the coal mines on either
side have encountered important flows of oil on fault planes.

The discovery well is located on a faulted dome at Hardstoft, Derby-
shire, where none of the coal mines had found oil in the fault planes.
It started in the coal measures, found wax in drilling through a fault, a
commercial supply of gas in the Millstone grits, which was muddied
off, and oil in the top of the limestone at a depth of 3078 ft. (938 m.).
This well has been flowing at the rate of 12 bbl. per day since June of
this year, and is estimated to have a pumping capacity in excess of 50 bbl.
The well has not been "shot;" first, because the transportation of
nitroglycerine on the roads of England is not permitted, and, second,
because the war emergency being over, the question of the ownership
of the oil has become acute, and when the present tankage is filled the
removal of the oil will undoubtedly involve a legal fight.

Two wells, located on domes south of Hardstoft, both started in the
coal measures, penetrated the Millstone grits without finding gas in
any considerable quantities, showed a little oil in the top of the limestone,
and are now drilling in the limestone, where they have encountered a
little gas. It is planned to " shoot" these wells whenever conditions
permit. Three wells on different structures to the north of Hardstoft
have encountered commercial gas in the Millstone grits, but have not
yet reached the limestone. The two wells which have been started on
the west side of the Pennine axis in Staffordshire have not yet reached a
sufficient depth to be interesting. The area in the center of England
that has important petroleum possibilities is between 20,000 and 30,000
square miles.

The two wells that are being drilled in Scotland are in an entirely
different category. They are merely " wildcat" wells, with a moderate
chance of being successful. One is located at West Calder, on a dome in
the oil-shale fields, 16 mi. southwest of Edinburgh, and the other on a
dome at Darcy, 10 mi. southeast of Edinburgh both in Edinburgh-
shire. They both start in what is considered the northern equivalent
of the lower part of the Mountain limestone, which is here for the most
part the oil-shale series. They will both penetrate between 2000 and
2500 ft. (609 and 761 m.) important untested sandstones underlying the
oil shales, and are expected to reach the old red sandstone (Devonian) at
from 3300 to 4000 ft. A certain amount of free oil and wax has been

6 PETROLEUM RESOURCES OP GREAT BRITAIN

found in connection with the shale mining sometimes in the associated
sandstones; sometimes on the faces of the igneous sills. This free oil
has always been considered as due to destructive distillation of the shale
by heat from the igneous rocks, but Mr. J. E. Hackford finds that it has
many things which distinguish it from an oil that could be produced by
the destructive distillation of the shales, and reaches the conclusion that
it has come from below after the igneous rocks had cooled. This, taken
in connection with the fact that the Devonian sandstones show some oil
in the north of Scotland and in the Orkneys, has led to the location of the
two test wells in Scotland.

The present work in Great Britain had its inception in 1914, when the
outbreak of the war enabled the writer and his associates to carry out a
long deferred desire to see just what the numerous indications of petro-
leum in Great Britain really meant. Thanks to the great mass of funda-
mental geological information which the Geological Survey of Great
Britain had collected and published, and particularly to the detail work
carried out in certain coal fields, it was possible in a short time to
present to Lord Cowdray the conclusion that the petroleum possibilities
of the Midlands of England were of a most amazing and striking
character. Lord Cowdray, after a momentary hesitation, shared our
enthusiasm. With the increase of the submarine menace, he offered to
place the services of his firm and his petroleum staff at the disposal of
the nation, free of cost, for carrying this work forward as a war measure.
This was a gift made to the nation without any commitment of any kind
on the part of the British Government to Lord Cowdray.

Special mention should be made of the work of Mr. Eugene L. Ickes,
a graduate of the University of California and an American geologist
of marked ability. Mr. Roderic Crandall, of Stanford University, who
was in charge of the technical administration of the work, and Mr.
Victor L. Conaghan, drilling superintendent, who was very kindly
supplied as a war measure by the United States Bureau of Mines.

The oil from the Hardstoft well has the following characteristics:
Specific gravity, 0.823; sulfur, 0.26 per cent.; gasoline, 7.5 per cent.;
kerosene, 39.0 per cent. ; wax, 6.0 per cent. ; gas oil, 20.0 per cent. ; lubri-
cating oil, 30.0 per cent. The oil is particularly rich in very high-grade
lubricants.

DISCUSSION

CHESTER W. WASHBURNE, New York, N. Y. (written discussion).
The work of Mr. Veatch and his associates in directing the work that
promises to add England to the list of oil-producing countries indicates
the value of science, as well as their ability to apply it. Englishmen long
have been searching the corners of the earth for oil, without recognizing

DISCUSSION 7

the possibilities at home. I would like to ask Mr. Veatch whether any
chemists have ascertained what constituents in the oil are responsible
for its susceptibility to oxidation. He says that, " while it is of paraffin
base, it oxidizes even more rapidly than an asphaltic oil." Can he give
us the percentage of unsaturated hydrocarbons, or any similar informa-
tion concerning the chemical nature of the oil? This experience in
England indicates the possibility of oil in other parts of the world that
have been neglected in explorations.

OIL FIELDS OF PERSIA

Oil Fields of Persia

BY CAMPBELL M. HUNTER, LONDON, ENG.

(New York Meeting, February, 1920)

PETROLEUM is found in almost every province in Persia. On the north-
ern frontier, along the southern shore of the Caspian Sea, it is found near
Enzelli and Shakhtesar and gas at Khoremabad. Oil is also found at
Gumish Tepe, northwest of Astrabad, on the southeastern shore of the
Caspian Sea. Further inland, to the south of Astrabad, oil is found at
Dchahkuh-i-balae, also on the margin of the Khorasan desert at Semnan,
115 mi. (35 m.) east of Teheran.

Along the western frontier, from northwest to southeast, oil is en-
countered at Ouschachi, north of Lake Urumieh; in the province of
Azerbaijan, at Zohab, Khanikin, and other places in the district of
Kormanshah in the province of Ardelan. Further south, in the province
of Luristan, oil is found east of Mendeli and in the Pusht-i-kuh districts.
Considerable quantities of oil are also obtained from Schuster, Maidan-
i-Naphtun, Ram-Hormuz, Beheban, which are almost on a straight line,
running northwest and southeast along the foothills of the Bakhtiari
Mountains. At Ahwaz, in the province of Arabistan, oil has been found
along another range of hills whose axis also lies in a northwest-southeast
direction.

In the Fars province, boring for oil has taken place at Daliki, and
indications of oil are found at Kheri, Fasa, Darab, and other places.
A gas show is also recorded at Kuhi-Sung-Atush in this province, 30 mi.
(48 km.) east of Darab. In the south of Persia, oil is encountered on
Qishm Island, also at Ahmedi and other places north of Bunder Abbas.
On the southeastern frontier, oil is found on the Sarhad range of hills.
Thus, oil indications have been noted over a distance of approximately
1100 mi. along the western and 700 mi. along the northern frontiers of
Persia.

HISTORY

The first working of oil in Persia of which there is any record took
place at Kir-ab-us, Susiana, now known as Kirab, about 57 mi. northwest
of Schuster. Herodotus (about B. C. 450) reported a well near Ardericca
that produced three different substances; namely, asphalt, salt, and oil.
The oil, which was black and had a strong smell, was called Rhadamance
by the Persians.

CAMPBELL M. HUNTER 9

At Daliki, many years ago, a well sunk to a depth of 124 ft. pierced
hard sandstone and blue clay and encountered semi-solid bitumen and
liquid petroleum in small quantities. The same company, the Persian
Bank Mining Rights Corpn., also drilled on the island of Qishm, though
unsuccessfully. Later, surveys at Zohab and near Schuster indicated more
favorable conditions. In the former district, oil has been exploited for
centuries from primitive, shallow, hand-dug wells, some being reported
to have yielded oil in undiminished quantities for upwards of 50
years.

In 1903, W. K. D'Arcy, prompted by rumors of oil in Persia, started
a systematic investigation of the country, and in 1903-4 drilled two wells
at Kasr-i-Shirin, one to a depth of 800 ft. (243 m.) and the other to
2100 ft. (640 m.) . Drilling was conducted in various districts, but without
any great success. After about 200,000 ($1,000,000) had been spent in
this way and there were serious thoughts of abandoning the whole proj-
ect, D'Arcy heard of oil seepages and springs in the neighborhood of
Schuster and had these examined. After overcoming much opposition
from the natives, a concession was secured and drilling begun. The first
bore hole, at a depth of 1100 ft., pierced the oil sands and the oil spouted
to a height of 70 ft., carrying away the derrick.

In 1909, the Anglo-Persian Oil Co. was formed with the object of
working the concession obtained by Mr. D'Arcy from the Persian Govern-
ment in 1901. This concession runs for 60 years, from May, 1901, and
gives the exclusive right to drill for, produce, buy, and carry away oil
and petroleum products throughout the Persian Empire, except in
the provinces of Azer, Badjan, Gilan, Mazanderan, Astarbad and
Khorasan.

Before the formation of this company, preliminary examinations and
tests had been carried out in compliance with the terms of the concession,
by the First Exploitation Co. The concession to the company provided
for the allotment to the Persian Government of 20,000 fully paid shares,
as well as a cash payment of 20,000, and a royalty of 16 per cent, of the
net yearly profits.

On the inception of the Anglo-Persian Oil Co., the actual holding
of the First Exploitation Co. was limited to 1 sq. mi. in the Maidan-i-
Naphtun field, which is situated in a territory belonging to the Bakhtiari
Khans. The agreement with the latter tribes provides that they shall
receive 3 per cent, of the shares in any company formed to work oil in
their country; and to facilitate the working of the agreement, it was de-
cided to form a second subsidiary company, known as the Bakhtiari Oil
Co., Ltd., to work the remainder of the oil-bearing lands in the Bakhtiari
country. All the shares of these two companies not held in Persia are
the property of the Anglo-Persian Company.

The concession taken over by the Anglo-Persian Oil Co. covers an are

OIL FIELDS OF PERSIA

of some 500,000 sq. mi., only a small part of which has been examined.
In 1914, the British Government decided to take an interest in the devel-
opment of the Persian oil fields, and to this end, entered into an agreement
with the Anglo-Persian Oil Co. under which they took up 1000 1 pre-
ferred and 2,000,000 1 ordinary shares.

PERSIA

REFERENCE

Oil Wells Proved Areas

Reported Oil Shows

mmnmt Anglo Persian Oil Company*s Concession

In 1917, the Russo-Persian Petroleum Co. obtained from the Persian
Government an exclusive concession for prospecting for oil in the district
of Ardebil, and in the provinces of Gilan, Mazanderan, and Astrabad.
In the same year, the same company purchased a number of oil-carrying
steamers and sent out a party of geologists under Prince Ameradzhebe.

CAMPBELL M. HUNTER 11

GEOLOGY

For the purpose of this paper, Persia may be divided into three
areas: Northern Persia, embracing the provinces of Azerbaijan, Gil an
and Mazanderan; western Persia, in which lie the provinces of Ardelan,
Luristan, Bakhtiari, Arabistan, Pars, Laristan and the Island of Qishm;
southeastern Persia, comprising the district of Mekran.

The oil-bearing region in northern Persia lies between Lake Urumieh
and the Caspian Sea, a distance of about 200 mi. in breadth, and belonging
chiefly to the Tertiary period. In the north of this region at Ahar, natural
shows of petroleum are seen in a stratum of apparently foraminiferous
sandstone, which gives off petroleum emanations a few feet below the
surface. There are also several mud volcanoes in this district. Be-
tween Ahmenabad and Ahar, the region is terraced in asymmetrical folds,
the principal axis of folding lying roughly due east and west with syn-
clines about 2 mi. apart, the dip on the one side being between 65 and
75 and on the other between 12 and 15.

To the south of Ahar, the greater part of the formations belong to
the upper Carboniferous period; and in the Savalian Kuh Mountains
in the southeast, rock salt and gypsum are found in large quantities.
Faulting is very prevalent in this range, associated with numerous highly
petroliferous mud volcanoes.

East of Ahar, at Ardebil on the Mugan steppe, extensive shell beds
resting on rocks of Pliocene age similar to those found at Baku exist; it
is thought that the oil fields of northern Persia are a continuation of those
of Baku. Similar shell beds exist near Marand almost due west of
Ahar, and near Sofian and Tabris, which is built on alluvial beds of Miocene
age. The country east of Tabris belongs to the Mesozoic period and
contains very considerable deposits of rock salt and gypsum. In a de-
pression close to Sirab, traces of oolite are found; and north and south of
this site Carboniferous shales are met with.

The regional tectonics of the Belfathemar divide, which lies to the
south of Sirab, consist of a lengthy anticlinal fold along which, at several
places, oil and gas escape; in warm weather fumes of sulfuretted hydrogen
and sulfur dioxide are found in the gulleys. It is the belief of Charles
Bouvard, Sir Boverton Redwood, and many others that the petroleum
of northern Persia is of organic origin. Toward the end of 1917, a geolog-
ical survey of Gilan and Mazanderan was in contemplation on behalf
of the Russo-Petroleum Co., which has acquired concessions in these
provinces.

The geology of southern and western Persia, especially to the north
of the Persian Gulf, has been investigated on a comprehensive scale by
Doctor Pilgrim who gives the following geological formations in descend-
ing order:

*od dtd oraJ rarf of littoral; rad
of tot* oT ThMfei OBMW, alfeffom oT M*v

uaH

i and iotorlMd4dtr*t of rock gypsum,

,,,,,,,,, nmtoM*.

tow oT Pffrf*,' MUM**, and Bahrain

In connect) u,< ,,,] ^< |ogy oT WMtern And wwthern Perain

roo#t iroporttt/ ,i n. - :-.MJ. - >}. i>akktli*i f dHo/

FiMf Mfoi, l>y far the mot import*t /UMJ widespread

of th<^ three, In mbdMM blO tftfiM dffUooi^ vj/..:Bflttlorgypium

bed*, plateau !, d J bed*. According to Don.or J'jlf/.u

J U.' !;..-. ,-< n ;-, MMM of l;iyri <,\ io:l- ;ihojl. JO f I,

clayi, and hale, The thicknem of tbene baaJ bed* w tti"l io /
1000 ft, and they appear to to repraented f rom take Urumleh, in the
north, to J5under Abba*, in the *outh, They are of reddwh color, due to

non oxi.lir c:oiifoiiu;thl.y ov ilyini/ i.he ba*al bed*, but. pritlj no

|ji. il tli-in.-inri-tUoii, an- I.I,.- pi;,!. ,,. -: :...,. < xl.c/Mj hoin

pl;.n, to liunditr Ahlmw. 'J'li^w:, Dodo/ iMj.'/uncon*ider* to bit il,-
e*t of the Far* *erie* with a thickne** of from 14,000 to 16,000 ft n
to 4576 HI.) at Kotal Mai',, but rapidly DH/./.H^ to 8000 n i,.-i /,-..

K.Mj.uhil-.h.-i pl;un ;ifil MM- Kol.al K;un;irjj. 'JJji-y roii,-.i,-.l. of hliji: ;tf,'l M -1

clay*, or marl*, alternating with *and*tone* m-i i.i.mly bedded fo**il-
iferoua HiJiiitOilMi> Thee limeftonei are most frequently fou/. i b i !.
lower todi and the *and*tone* predominate in the upper.

i IM pi;,i. ;..u I,.,] ,, (n i m erge into.tlia coa*tal bed*, which v;,; V Croa

itOO h, 1000 II II. 11,1' I'll. ;.l,.j ,,- . -,-npr, , ,j ,,| ,,;,!, ;,,;,, , |;, ,,,

marl*, pa**ing fom^time* into *oft argillaceous lime*tone. Interbedded
with thwe are thin oalcareou* band* crowded with shell* and grit Raft-
ing with great unconformity ofl <i" l (1 ar *erie* i* the Bakhtiari *erie*,
which consists of dotrital deposit - < > i ,, ,i , ,,.-,, . ,,, , ,!,.,,,!
i ooo ft, thick, and IJHH UM its most characteristic rock a conglomerate of
red and green chert pebbles. This *mr in pntdjoally unforwilifi rou

ami ir: i,.,l. inoir i. ,:!, I Ili.-ui UK I'll. i. . >,. ;.JM

111 it papT M-ail |,I.|',M. Ih.- I;i;-lil,ul ol l'-l.n,l-iiin 'I < lu,,l,}'i I n,

London (in 1018), Messrs, Busk and Mayo, describing tin )'. .i.htiari
country arid dealing with these sen !< M!< \.\\t- I<'arH scries into a lower
gypsiferous group, varying in thicknenh hum Jooo i., :;:,f)0 n, nun \ (l /<,;>
m,); a middle, or passage, ^roup, himilar to Docioi rilfn.,,';, plah-;m

CAMI'ltl- I.I. \t. m '. ( i r<

group, imt with * thickness rarely exceeding 1000 ft.; and an upper, or
argttlaoeous, group consisting of purple Mid lid thai** and clay* with
intercalated massive sandstones, consisting of chert grains Mounted by
a calcareous matrix* Du to the presence of plant remain* and the ab-

*riccof marine* fo^il*, thy <-oriMd<-r< d 1 1,,. i, PP , r K mup ic, l,< -i,f !< uMm,<
origin and about 2700 f< . Ihmk.

The? Hakhfiari wri**, which ihry cjoiiMdrr a M-dime-nt df DOB BMttfa
origin, being deposited during a period of earth movement producing up -

lift :iti<i d<t>r<*fa riloriK W<>11 dofm< d Imrs, &&! ,!* K ,rc,t1<M (huKtu:,-
c,f :tl.<,uf l." ; ()(KI ft. (<K)7;> rn.) in (he undine, thu:- {<..tn! The |ow<i

group of thin ttrie*, about 12,000 ft. thick, consist* of cUyii, thaiei, and

.t,f..:tl: t t..l ::,.,. 1-1, r,c W ritul fcir^loitlc Trif c -s ;tl <M |l:irc^, p:t t f inila . 1 x

toward the* top of the group, which an* often 1500 ft. thick and are of

cMlaic; form. Although oil :nd oily r< >Kiu< ^ rttv fouml n, p.-uf> d |U|

group < > ;.r fliougMtobt iimply duttertdaporition from the adjacent
Fan iMriet. The upper group of thin erie<i rente uneonformably upon all
rock* blow, exeept in the nynclinal troughn, and conniuU of conglomerate

of wc-ll rfiutulfd Inru^loric :tnd lut( p<hl.lcr< u.ll rutirrifrd ((. F fl,<J :,.>.)

about 2000 ft. thick. Tht typical y nclint in the Bakhtiari district mc A-
suren about 7 mi. (11 km.) aero* and in At trough ha* 15,000 ft, of the*
Hakhiirm MTJC-N ovc-rlyit^ .VKK) ff of l-ar NfiM, Th' V OOfirfdCI *A1
further -:trlh movc'irc>iif>, ror.liniMnjr, fo tlu i.to<nf. hnvc produ<l ..
v<?ry romplic-ulrd MTJC:^ of f.-inhKe i struct ur<> \\ifh ihtur-i f:tul(:> < <>mm F up
to the surface.

Oil ho* been fc,....d ... thi district to be contained in the detriul
limMtonei forming the bane of the Fan lerie* and has \wn flowing at
Maidan-i-Naphtun, under ttrong pr*sjre, for the last 10 yean. Th
accompanying table nhows the differwicc between tht tbieknewi of the
variou* formatioiui, a calculated by Doctor Pilgrim and Messrs.
Bunk and Mayo:

t-.. ,.,,. M,,.,.

nrii 1,000 19,000

IkMMU, 1,000 Lowr or

MOO

iteftMtt Ml, 1,000 MiddU or pom** awup, 1,000
CoMUlM, 1,000 UPSMNT or argill<Mous group
2,700

In dcicribing the Ahwas Pusht-i-kuh country, Messr*. Husk and
Mayo state that there i* an anticlinal utructure running for 100 ml.
(100 km.) in a went-northwest and east-southeast direction through
Ahwas. This structure forms the furthest outlying fold of the Iranian
Mountain chain Mid is asymmetrical, having a steep vertical, or in v< t f i
dip on the southwestern face Mid a gentle slope on the northeastern

limb. In the; rioighborhood of AhwaS, tllS SfSSt rf ths

OIL FIELDS OF PERSIA

form of elongated domes, and denudation has shown that the lowest 200
to 300 ft. (60 to 91 m.) of exposed beds belong to the middle group of the
Fars series.

There is one main oil horizon in the central field, which has been proved
at depths varying from 1200 to 1300 ft. (365 to 396 m). This horizon
is responsible for the greater part of the production of this field; and as
the oil is found in a hard porous limestone, a steady production is obtained
with little necessity for cleaning out the wells.

At the White Oil Springs, two seepages occur on the crest of the fold,
from which a colorless oil resembling kerosene is obtained. The produc-
tion amounts to about 20 gal. (75 1.) per day, and is used by the natives
for domestic purposes.

The Ahwaz anticline is about 36 mi. (58 km.) to the southwest of the
Maidan-i-Naphtun fold; and although no evidence of petroleum appears
at the surface, the White Oil Springs horizon is expected to exist at no
great depth.

At Qishm, oil issues from the lowest exposed beds at two places,
about J mi. apart. The seepages are not considerable.

TECHNOLOGY

There is little published information relating to drilling methods on
the Persian oil fields. D ' Arcy, in his early exploration work, employed
Canadian drillers and Canadian drilling rigs. This system, but with the
wire rope taking the place of the old-fashioned drilling rods, is now exten-
sively used on the field, though rotary drilling has been tried. Inserted
joint casing is generally used, as formations encountered give little trou-
ble through caving. Considerable gas is yielded by the wells and is used
under the boilers.

TABLE 1

Fractions

Flash

Location

cifit
Grav-
itv

Point
of
Crude,
De- r

Ben-
sine,

Kero-
sene,

Lub-
ricat-
ing

Sulfur

Odor

Color

II* jr

grees !

Per

Oils,

Cent.

Per

Cent.

Schuster District.

0.927

27.0

Dark green

White Oil Springs

(Ahwas)

0.773

Present

Inoffensive

Light straw

Tchiah Sourlch

0.815

Low

9.4

57.6

0.4 per cent.

Inoffensive

Brown,

(Near Kasr-i-

present

strongly

Shirin).

fluorescent

DaUki

1.016

170

Present

Strongly of

Dark brown

sulfuretted

hydrogen

Qjshm

0.837

100

Pleasant

Brownish red

DISCUSSION 15

No recent production figures have been published, but it is understood
that the wells come in as gushers and continue to flow for a considerable
time. One well, at least, is reported to have yielded over 100,000 tons
of oil by flowing. Early in 1919, it was stated that the wells already
drilled were estimated to be capable of producing 5,000,000 tons per
annum. Table 1 gives brief particulars of some of the oils.

From Maidan-i-Naphtun, which is situated about 800 ft. above sea
level, the oil is conveyed to the refinery at Abadan through two pipe
lines of 6-in. and 10-in. (15 and 25 cm.) diameter, the distance being
about 145 mi. (233 km.) . The diameter of the former pipe line is increased
to 8 in. about 53 mi. from the field to enable the production from White
Oil Springs and Ahwaz to be pumped to the refinery. Upon the comple-
tion of certain additional pumping stations, the joint pipe lines will have
a total carrying capacity of about 3,000,000 tons say 22,000,000 bbl
The refinery at Abadan, which is an island at the head of the Persian
Gulf, was completed in 1913, with an estimated annual throughput
capacity of about 240,000 tons (1,750,000 bbl.). Since then the refinery
has been considerably extended, and is now capable of treating the bulk
of the company's production.

Initially, considerable difficulty was experienced in eliminating the
sulfur present in the Maidan-i-Naphtun oil. Various processes were
tried, and it is only within the last year or two that a satisfactory treat-
ment has been evolved.

PRODUCTION STATISTICS AND FUTURE POSSIBILITIES

Up to 1916, about thirty wells had been drilled at Maidan-i-Naphtun,
all of which were gushers; no wells had at that time been put to pump.
The production for the year ending March, 1912, was about 600,000 bbl. ;
during the ensuing six months the yield had been increased to 1,000,000
bbl. Since then a considerable number of additional wells have been
brought in while a still larger number have been drilled to the oil sand,
but not completed pending the development of increased marketing
facilities.

While little information has been published by the Anglo-Persian Oil
Co. on the development of its concession, there can be no question that
Persia is destined to furnish enormous quantities of oil, and to take
a leading position among the world's great oil-producing countries.
From the outset, the company's production has been greatly in excess of
its transporting, treating, and marketing facilities.

DISCUSSION

THE CHAIRMAN (E. DEGOLYER, New York, N. Y.). The Persian
fields are being operated by the Anglo-Persian Oil Co., of which the British
Government has control, under what amounts to a monopoly. According

16 OIL FIELDS OF PERSIA

to the company reports, some of the wells discovered are among the
largest in the world. The country is becoming extremely important in
the production of petroleum at the present time. According to the
estimate of the United States Geological Survey in 1918, Persia produced
7,200,000 bbl. of oil, and was fifth in importance among the producing
nations.

The Chairman of the Board of the Anglo-Persian Oil Co., in reporting
to the stockholders in 1918, mentioned a well that had produced 1,500,000
tons with no apparent diminution in pressure and no apparent diminu-
tion in productive capacity. I think that American petroleum geologists
and technologists have been overlooking the importance of the Persian
fields as a source of supply.

DAVID WHITE, * Washington, D. C. In connection with the description
of the oil indications of Persia and Mesopotamia, mention should be
made of the recent publication by the Hamburg Colonization Insti-
tute of a rather extensive memoir by Walter Schweer. This report,
which was evidently compiled for German consumption when the war
should be over, contains many details concerning the distribution and
character of the oil indications, with something of the geology and the
concessions held by various countries in Turkey, Palestine, Arabia,
Syria, Persia, and Armenia. This report will be found very valuable and
helpful by Americans interested in the great potential oil fields of the
near East.

* Chief Geologist, U. S. Geol. Survey.

OIL FIELDS OF BUSSIA 17

Oil Fields of Russia

BY A. BEEBY THOMPSON AND T. G. MADGWICK, LONDON, ENG.
(St. Louis Meeting, September, 1920)

FOR more than 2500 years, natural gas issues in the Surakhany
district of the Apsheron peninsula were the object of pilgrimages by fire
worshippers and Hindoos from Burma and India. Even as late as
1890, Hindoo priests conducted ceremonies in a temple at Surakhany,
which probably replaced a more ancient one; but later, the visits of the
pilgrims were prohibited in order to check the spread of Asiatic diseases
in that region.

For centuries, limited supplies of oil have been abstracted from shallow
excavations in the Caspian oil belt and dispatched into the interior of
Asia and elsewhere for medicinal and industrial purposes. Statistics
show a yield of 37,400 bbl. in 1863, but only since 1869 has there been
serious development; in that year the yield was 203,000 bbl. At that
time, hand digging was supplanted by drilling, and the enormous wells
that resulted from tapping sources hitherto beyond the reach of operators
completely demoralized the industry for a time, owing to inadequate
outlets for the products.

The early activities in this area were greatly hindered by annoying
taxation, monopolies, imperial land grants, etc., but when these were
revoked or adjusted, in 1877, the industry sprang into prominence and,
between 1898 and 1901, the Baku fields produced practically one-half
of the world's supply of oil.

Within a few miles of Baku lie the two richest oil fields in the world;
viz., the Balakhany-Saboontchy-Romany and the Bibi-Eibat, the latter
constituting almost a suburb of the city. For many years the gasoline
obtained in the refineries of the Baku area was burned in pits, being
considered an undesirable product, and until 1870 the residue also was
destroyed, its value as a fuel not being recognized. Kerosene was the
main product sought by the refiners. It was shipped across the Caspian
Sea and up the Volga to the industrial centers of Russia. Only on the
completion of the Baku-Batoum railway did the Baku oil fields secure
important commercial communication with the outside world through
the medium of the Black Sea. The first tank steamer was successfully
launched on the Caspian in 1879, by Messrs. Nobels, for transporting
oil in bulk instead of in barrels. In 1905, an 8-in. pipe line to Batoum
was completed; this was capable of transporting to seaboard 8,000,000
bbl. of kerosene per annum.

VOL. LXV. 2 .

18 OIL FIELDS OF RUSSIA

In 1903, the important Grozny oil field was proved by a great flowing
well sunk by an enterprising Englishman, who, however, was ruined by
the claims for compensation made by peasants whose habitations and
lands were destroyed by the deluge of oil, which could not be controlled
for years. The property on which the well was drilled has since given
over 300,000 bbl. of oil per acre.

In 1901, general interest was directed to the Binagadi oil field by the
bringing in of a 10,000-bbl. well. The field lies close to Baladjari railway
station and only a few miles from Baku and the refineries, to which a
pipe line was subsequently laid. In this year, also, an important oil
field was located at Berekei; but after a few years' work hot sulfurous
waters flooded the oil sands and, as no suitable means for its exclusion
were devised, the field was practically abandoned, although some wells
continued to yield for years. Berekei lies on the Caucasian railway near
the port of Derbent. The oil from the field was piped to the railway and
taken in tank wagons to its destination.

Another interesting field is Holy Island, off the north coast of the
Apsheron peninsula, where 400-bbl. wells have been struck and a consider-
able area has been proved to be oil-bearing. Oil is shipped direct to the
Volga by tankers proceeding from Baku. In 1908, the Surakhany district
a few miles southeast of the main Saboontchy oil field was developed by
deep wells, and large gushers of the typical Baku oil resulted from
drilling beneath the upper light oil and gas-yielding beds that until
then had been exclusively worked.

For many years the island of Cheleken, off the Asiatic coast of the
Caspian Sea, near Krasnovodsk, had been the scene of some moderate
operations; but from 1911 onwards large yields were obtained from wells
sunk in the Ali Tepe district in the southwestern part. These wax-
containing oils were generally shipped to Baku for treatment at Black-
town, the refinery suburb of Baku.

In 1909, the Maikop oil field attracted considerable attention as the
result of a large gusher of light oil being struck by almost the first trial
well in the Shirvansky district. Since that time, a fair production has
been obtained although the very prolific area was proved to be small.
This field lies on the northern flanks of the western, and sinking, end of
the Caucasian range, over which a pipe line was laid to the port of Tou-
apse. Pipe lines were also laid to Ekaterinodar, where a refinery was
erected, as well as Shirvansky.

A promising oil field was developed, about 1910, in the Emba district
north of the Caspian sea and inland from the port of Gurieff. Around
Dossor, large flowing wells were struck and, prior to the war, extensive
arrangements were being made to dispose of the product. Pipe lines
were laid to Bolshaya Rakashka, where refinery operations were con-

A. BEEBY THOMPSON AND T. G. MADGWICK 19

ducted, and submarine pipe lines were carried through the shallow-water
belt to facilitate shipment of the products up the Volga.

A single Turkestan field, in Fergana on the Trans-Caspian Railway
at Chimion, has yielded substantial supplies of oil that finds a ready
local market. It is said that at Maili Sai good productions resulted from
trial wells sunk by the government.

LEASING OF OIL LANDS

Many original grants of oil lands were gifts bestowed on court
favorites, but when some system was introduced terms were based solely
on the unique Baku conditions, and prospecting licenses of about 100
acres were granted from which 27 acres could be selected when oil had
been found. The original annual rentals of $2 per acre for the first
ten years, increasing ten times each ten years, were soon superseded by
percentage royalties, which varied from 25 per cent, upwards, with
minimum annual payments. At one time tenders on a royalty basis
were publicly solicited, but speculation led to such absurd offers that
the government abandoned the practice. For instance, at times, oper-
ators tendered royalties of 75 per cent, with large minimum payments
merely to protect their boundaries from aggressive competitors.

The Cossack lands of the Terek-Kuban provinces were subject to
a rental of $5 per acre per annum and about 4 c. per bbl. royalty for
the first 120,000 bbl. and 2 c. per bbl. afterwards; but rights were reserved
to revise the royalties after 12 years. Insistence in perpetuating the old
leasing laws based on the unique oil fields of Baku has been a great hin-
drance to prospecting in Russia, and it is to be hoped that some more
rational policy will be introduced in the near future.

DISPOSAL OF RUSSIAN OILS

The products of the Baku oil fields go largely to supply the internal
demands of Russia through the medium of the Caspian Sea and the river
Volga, although the freezing of the northern Caspian and the Volga in
the winter months restricts movements of oil to about 8 months in the
year. A pipe line and railway to Batoum are available for the convey-
ance of lamp oils and other oil products to the Black Sea, where ocean
vessels can approach via the Dardanelles. The large refineries are
situated at Blacktown, a suburb of Baku.

Oil from the Grozny field and refineries is either piped to the port
of Petrovsk on the Caspian Sea or sent by rail to Novorossisk on the
Black Sea. From Holy Island and Cheleken, oils are mainly sent to

20 OIL FIELDS OF RUSSIA

Baku for treatment; while the North-Caspian (Emba) oils are shipped
at Bolshaya Rakashka for transmission up the Volga. Central Asian
oils find a ready Asiatic market and are useful for the Trans-Caspian
railway service. Maikop oils can either be pumped to Touapse on
the Black Sea or to Ekaterinodar, a large town that feeds a wide,
fertile, agricultural region. Extensive tank farms are situated at Baku,
Grozny, Batoum, and Novorossisk; also up the Volga, where the winter
supplies are accumulated during the summer months.

OIL MANIFESTATIONS

Probably no country in the world exhibits a greater display of oil-
field surface phenomena than Russia. There are thousands of square
miles flanking the Caucasus Mountains and encircling the Caspian Sea
that justify an investigation. Difficulties of language, inaccessibility,
danger to life, indifference of the authorities to their mineral resources,
and irritating restrictions have contrived to suppress any initiative that
existed. For miles around the Baku oil fields, the oil series lie spread
out like the leaves of a book under the nearly desert-like surroundings of
that devastated region. Mud volcanoes on a gigantic scale in every stage
of activity may be witnessed, as well as perpetual fires fed by incessant
issues of natural gas. Acres of asphaltic residues and streams of viscous
oils oozing from immense thicknesses of oil-soaked sands are common.
These phenomena, mingled with sulfurous waters, present problems for
study that are nowhere else reproduced on such a vast scale. Over
extensive areas, shallow hand-dug wells sunk into the outcropping
inclined or vertical strata yield appreciable, and often considerable,
quantities of oil.

Many equally imposing exhibits of oil phenomena may be seen
on Holy Island and Cheleken, where for miles numerous oil residues,
gas exudations, and sulfurous- and salt-water issues may be examined
along the outcropping beds. Fierce outbursts of oil and gas occasionally
startle the inhabitants, cause damage to property, and loss of life. Twice
within the writer's knowledge, such outbursts in the Yasmal Valley have
caused conflagrations that illuminated the sky for miles around each
night. Big outflows of oil have also been recorded; and during earth-
quakes, considerable alarm has been occasioned by the ignition of gas
that issued from cracks in the earth. Little less interesting are the great
mud volcanoes of the Taman peninsula, which area has not received
the attention its manifestations merit.

An interesting phenomenon is the submarine gas issue. Prior
to the development of the Baku oil field, several places in the Caspian
Sea were known where the ebullition caused by escaping gas was suf-
ficient to capsize boats.

A. BEEBY THOMPSON AND T. G. MADGWICK 21

GEOLOGY

As is the case in many other oil fields, structure is the dominating
feature of the chief oil fields of Russia. Comparatively simple partial
domes characterize the two great fields of Baku, but both have flanks
on one side where the oil-bearing series outcrop and display those surface
phenomena usually associated with oil. The whole series of Tertiary
strata in which the oil is secreted consists of unconsolidated clays, sandy
clays, and sands of all grades of fineness that readily break down and
crumble when pierced by the drill. Their fragile nature is the cause of
unusual difficulties in drilling, as throughout a thickness of over 3000 ft.
there are constant irregular and ill-defined alternations of sands and clays
that merge into one another in a way that makes a log very unreliable
when prepared from collected samples. Some sands are charged with
oil, some with gas alone, and others with oil and gas. Many of the water-
bearing quicksands run freely on penetration and fill the hole to a depth
of hundreds of feet. At times, too, oil-saturated clays continue to ooze
into the well, rendering progress very difficult.

Certain sandy horizons can occasionally be traced for some distance
and definite water and oil horizons have been located within restricted
areas. Generally, however, the pliable beds have been so contorted and
crushed that no single bed can be recognized for any considerable dis-
tance. Geological study was always made more difficult by the further
disruption the beds sustained when rich oil sands were struck. Masses
of surrounding strata were expelled on penetrating a rich oil sand;
in addition, thousands of tons of sand was either ejected with oil
during flows or removed with the oil during its abstraction. As
much as 50 per cent, sand (by weight) has been suspended in the
oil for a time, and often 10,000 tons of sand have been ejected daily,
for some weeks, from a well piercing a virgin and prolific sand body.

Stratigraphy

The oil-bearing rocks of the Russian oil fields are of Miocene and, to a
less extent, of Oligocene age; that is to say, occur in the deposits of the
old Caspian-Mediterranean sea that surrounded the Caucasus and gener-
ally lie unconformably upon the more highly disturbed Cretaceous beds.
The large area covered by these deposits, particularly along the foot of
the northeastern slopes of the mountains, has enabled very many occur-
rences of oil to be noticed. It is these Tertiary rocks alone that present
any interest, although considerable quantities of gas have occurred in
the Cretaceous, a noteworthy instance being during the construction
of the tunnel on the Novorossisk line. Oil seepages are likewise known
in the Cretaceous rocks.

OIL FIELDS OP RUSSIA

Detailed geological study of this great area has not been attempted,
in fact, published maps have been confined to the districts in which
development has taken place. Tabular columns are appended of the
Neftianaia-Shirvanka area in the Kuban, or northwest area; the Grozny,
or northeast field; and the Apsheron Peninsula, the most eastern portion
and seat of by far the most important development, the Baku fields.
These tables show that the Miocene rocks present similar character-
istics throughout the northern flanks of the mountains but that at
Baku there is a distinct facies, which is largely concealed by the char-
acteristic Pliocene and Post-Pliocene formations of the Caspian Sea.
Nevertheless, the Apsheron Peninsula as a whole presents a very
complete exposure of the succession, notably in its northwest corner
and in the Yasmal valley and adjacent hills farther south, while the
Pliocene ^and younger rocks are seen around the fields and farther

TABLE 1. Section of Apsheron Peninsula (after Golubiatnikov) .

STAGE

FOHMATION

Coastal deposits of present Cas-
pian extending to 10 m. above
present sea-level.

Older Caspian deposits forming
conglomerates at a height of 12
and 26 m. and reaching to a
height of 34 m. above present
sea-level.

Aralo-Caspian Terraces at a
height of 96 and 186.5 m.
(beds not disturbed.)

Bakunian (disturbed).

Apsheronian.

THICKNESS,

METERS

5-10

Pontian (?)

Transition beds.

LlTHOLOGlCAL CHABACTEB

Sands, clay, and shell frag-
ments.

14 Sands, clays, boulders and shell
conglomerates.

3-6 Limestones, sands with boulders
and conglomerates.

46 Limestones, sandstones, sands,
clays and conglomerates.

453 Limestones, boulder limestones,
oolites, shell beds, sandy lime-
stones, calcareous sandstones,
sands, marls, sandy clays, and
clays; limestones predominate
in the upper beds, sands in
the middle, and clays in the
lower; the thick clay series
(110 m.) contain layers of
tufaceous sands at base.
76 Dark colored clays interbedded
with sand and marl; contain
gas at Bibi-Eibat.

11.3 Dark clays with interbedded gas
sands; sands gas bearing at
Bibi-Eibat.

A. BEEBY THOMPSON AND T. G. MADGWICK

TABLE 1. Section of Apsheron Peninsula (after Golubiatnikov) .

(Continued) .

STAGB FORMATION THICKNESS, LITHOLOGICAL CHARACTER

Akchagylian.

Fresh water formation.

49.4

490

Unfossiliferous series:

First series, sand oil bearing 434

at Bibi-Eibat.
Second series, sand oil bearing 185

in Yasmal Valley.
Break hi the series until the
Spirialis beds
Spirialis beds. 98

Dark colored clay shales and
shaley clays interbedded with
limestones and white tufaceous
sands; the sands are gas and oil
containing in Bibi-Eibat.

Clays, sandy clays, sands with
clay and sand; clays pre-
dominate.

Sandy clay series; sands pre-
dominate.

Sands and sandstone with inter-
bedded clays.

Siliceous, calcareous and sandy
clay rocks with interbedded
ferruginous sandstones; in
places oil bearing.

Cedroxylon beds. Dark colored, laminated shales

with concretions of siliceous
sandy rocks.

Amphisyle beds. Shales, dark, and chocolate

colored, weathering yellow.

Lamna beds. Green, sandy clay shales with

interbedded siliceous sandy
rocks and white marls; oil
bearing in places.

TABLE 2. Section of Grozny Field (after Charnotsky)

STAGE
Meotic.

FORMATION

Akchagylian

THICKNESS,
METERS

LlTHOLOGICAL CHARACTER

Middle Sarmatian Beds with fish

formation. and remains of

Cetacea.

Spaniodontella

Transition from

beds.

Sarmatian to /.t

Mediterranean.

Chokrakian.

Mediterranean Spirialis beds.

Up to 425 Limestones, conglomerate of
limestone pebbles, calcareous
sandstone, and clayey sands,
calcareous clays.
Unconformity.

43 Calcareous (and shaley) clays
with numerous limestone beds.

50 Shales, sandy clays, clay sand-
stones, calcareous clays and
sandstones, pure sandstones,
water sands.

370 Shales, sandy clays, clay sand-
stones, pure sandstones, cal-
careous sandstones, limestones,
(often nodular) , dolomite;
sandstones oil bearing.
? Black shales, limestones, black
nodular limestones, dolomite.

OIL FIELDS OF RUSSIA

TABLE 3. Section of Neftianaia-Shirvanka

STAGE
Meotic.

THICKNESS,
METERS

Upper
Sarmatian.

Middle
Sarmatian.

Lower
Sarmatian.

Middle Miocene
Mediterranean

LOCAL HORIZON

Congeria Panticapea
beds.

Mactra Caspia beds.

Beds with typical Mid-
dle Sarmatian fauna.
Cryptomactra beds.

Beds with Lower Sar- 400-500

matian fauna.
Beds with fish and plant

remains.

Spaniodon beds.

Spirialis beds,
j Chokrakian.

in E

Lower Miocene. Oil formation.

Upper
Middle

Lower
Senonian.

Aptian

Foraminifera beds.

Beds with Pecten
Bronni.

Beds with Ammonites.

LlTHOLOGICAL CHARACTER

Dolomitic limestone, at
base dark marls.
Unconformity.

25-30 Thin clay beds, a few
+ thin partings of ferru-

ginous sandstone, shell
beds, gypsum.

thin Dark gray clays, at top
beds of shells.
Dark gray marls, at
base thinly laminated
gray marls.
Shell limestones.

Dark gray marls with
beds of gray thinly
laminated marls.
10-15 Compact marly lime-
stones with porous
partings.
200-400 Dark marls and yellow

gray marls.

20-25 Sands and limestone,
shell beds, dark marls.
225 Dark shaley muds not
(Neftianaia) effervescing in HC1;
beds of coarse sands
and sandstones becom-
ing gravels in places
480 or conglomerates; most
(r. P. shekh) beds contain oil.

800 White clays and marls,
beds of shaly bitumi-
nous marls.
Green-gray marls.

Unconformity.

White chalk marl with
few beds of dark marls
and coarse sandstones.
Unconformity.

Dark sandy clays with
beds of coarse sand-
stone.

east. The Grozny field, forming as it does a very complete instance of a
subsidiary fold, may well be referred to as a classic example of the asym-
metrical anticline; it yields no exposures of the older rocks. Still farther
westward, in the Kuban area, the development has been along the mar-

A. BEEBY THOMPSON AND T. G. MADGWICK 25

gin of the Tertiaries where they are creeping around the final Cretaceous
anticlinorium of the Main Range before it disappears beneath nearly
level younger formation in the Taman Peninsula to reappear under simi-
lar conditions in the Crimea.

The same formations occur south and southwest of Baku and are
recognizable across the Caspian. It is impossible to draw any geo-
logical limit to the oil province of Southern Russia, it must be studied in
the future as part of the Eurasian Fields.

Structure

Regionally, the structure is that of folding parallel to the main ridge
of the Caucasus with development of asymmetric folds along the north-
east side, more disturbed conditions to the south, and gentle plunging
of the Tertiaries and Pleistocene at the ends, with quite considerable
local folding in the thick series of plastic rocks composing the earlier
Tertiaries of these districts. Two well marked directions of folding
northeast and northwest, of which the former is the older, are recognizable.
The intersection of these two lines at the Taman and Apsheron Peninsulas
leads to local development of great pressure, which, acting on the plastic
material, gives rise to the phenomenon of "salses, " or "mud volcanoes"
as they are often called, in which the softer underlying strata are squeezed
out in the form of mud, associated with much salt water and gas, the
latter being composed of hydrocarbons and at times emitted on a grandi-
ose scale. The exuded material forms considerable hills, at the top of
which a crater shows activity, even in times of relative quiescence.
The rather complex structures resulting from the intersection of these
folds are often hidden beneath the Pleistocene rocks, which partake
of no folding, and the Pliocene which have suffered slight deformation.
This is especially the case in the Taman peninsula. It is also the case,
to a certain extent, in the Apsheron peninsula though good exposures
exist.

The Apsheron peninsula is built up of Pleistocene and Tertiary rocks
and both the Pliocene and the Miocene rocks are well developed. It is
the Upper Miocene that carries the pay so far developed. The shell
limestones of the Pliocene, which form the Baku building stone, are less
easily denuded than the Miocene rocks and so form escarpments around
the oil fields, usually bordering plateaus, while the Miocene rocks, where
exposed, form gently undulating country.

The Akchagylian (Upper Miocene) contain abundant fish remains
and thin beds of volcanic ash. The only known occurrence of pay in
them is at Surakhany; it is of the filtered type and, therefore, secondary.
The fresh-water formation contains shell remains and algae. It covers.

26 OIL FIELDS OF RUSSIA

large areas in the older fields but is concealed at Surakhany. The under-
lying unfossiliferous series forms with it the source of the bulk of the
oil hitherto won in Russia.

The unconformable Lower Miocene, capped by the hard siliceous
limestones with very characteristic casts of Spirialis, which form a useful
mapping horizon, is petroliferous; especially noticeable are the Oligocene
fish shales, but these strata have yielded no pay.

Four directions of folding occur, northwest, meridional, latitudinal,
and north-northeast. The first, that of the main Caucasian ridge,
prevails at Bibi-Eibat, Holy Island, and over much of the northeast part
of the peninsula; the second at Surakhany. Many folds are subject to
change, and complex structures ensue, in the formation of which faulting
stands in close relation. Faults are usually of small throw and coincide
with the axial crests, but three important lines must be noted as they
dominate the Peninsular structure. The first is the circular uplift
following the ridges Kabiriadig-Puta, Atashka-Shaban-Dagh, and Kobi-
Bos-Dagh; this lies west of any important developed area. The second
runs along Atashka-Shaban-Dagh, Gyokmabj-Khurdalan, and Binagady;
and the third through Fatmagi-Dygia, Kir-Maku, Balakhany-Saboont-
chy-Romany, and Surakhany-Zykh. These two lines form, with the
Bibi-Eibat fold, a horseshoe line open to the sea; it is along this line that
the big production has been obtained. The last important tectonic move-
ments took place at the close of the Upper Pliocene period, the next
before was at the commencement of the Upper Pliocene, while between
the Middle and the Lower Oligocene much greater dislocation took
place.

Oil Occurrence

The following horizons are known to carry oil:

1. Middle Pliocene: lower Apsheronian at Surakhany and Romany.

2. Lower Pliocene : Pontian at Bibi-Eibat.

3. Akchagylian: at Bibi-Eibat, Surakhany, Romany.

4. Fresh-water beds: at Bibi-Eibat, Surakhany, Romany, Saboont-
chy.

5. Unfossiliferous beds: Puta, Atashka, Khurdalan, Binagady,
Kir-Maku, Balakhany, Holy Island.

6. Lower Miocene: (Spirialis) Puta, Atashka, Kobi, Gyokmabj,
Khurdalan, Binagady, Holy Island.

7. Amphisyle beds: Sumgait.

8. Lamna beds : Western hills from Kobi mud volcano onwards.
The impregnation is sporadic, thus the phenomenally rich fresh-water

beds beneath Bibi-Eibat and Surakhany show no signs of oil on their

A. BEEBY THOMPSON AND T. G. MADGWICK 27

outcrops in the adjacent Yasmal valley and Zykh, respectively. These
facts lend weight to the hypothesis that their oil is in secondary accumu-
lation, which would have been facilitated by the downward increase of
permeable strata and the big unconformity above the Lower Miocene.
The temperatures of the oil at Bibi-Eibat have been acquired in accord-
ance with the geothermals, hence the invasion must be mainly a long
accomplished fact.

Of the eight horizons, the third has importance in Surakhany for gas
and "white oil;' 7 the fourth is the most prolific and is of value in Surak-
hany, Saboontchy, Romany, and Bibi-Eibat; the fifth in Balakhany,
Binagady, Holy Island, Khurdalan, on Atashka, and near Puta Station.

Surakhany. The Pliocene and Miocene rocks are folded into a broad,
flat anticline striking north and south. Eastern dips are 10 to 20;
the western 4 to 10. The visible fold continues to the north end of
Surakhany Lake and southward toward the faulted area at Zykh. The
crest is much faulted and in the salt lake are numerous fissures filled
with inspissated oil, while over a wide area fissures emit gas. The oil
zone having now been proved, by drilling, to continue through to
Romany, it is probable that the two areas are on one curving fold.

Gas springs occur over the whole central part of the district, in the
Lake, on the hill Atashka (" eternal Fires"), at the Temple, and in the
depression of Karatchkhur. To sink 20 to 30 ft. is enough to strike gas.
The upper gas beds cover an area of 4800 m. by 1500 m. (1780 acres) and
represent the apex of the fold. Outside this area, the same beds contain
no gas. Drilling has shown that all porous beds in the upper strata
contain gas; the lower, gas and oil. From 36 m. (118 ft.) to 480 m.
(1575 ft.), twenty-three gas sands were struck, the pressure at times
reading 30 atmospheres.

White oil begins at 200 m. (656 ft.), at the top of the Akchagylian,
and increases downwards. Only the central region is oil bearing. From
200 to 335 m. (656 to 1099 ft.) five white oil sands were struck. The
specific gravity is 0.785.

Black oil was first struck at 480 m. (1575 ft.) in the fresh-water
formation, as previously determined by Golubiatnikov. During recent
years, great development has taken place below this. The first horizons
yielded oil having a specific gravity of 0.820.

Balakhany, Saboontchy, Romany. A wide, faulted anticline represents
the continuation, southeast of the mud volcano Bog-Boga, of two folds,
that of Kir-Maku to the northwest and Binagady more westerly. The
fold pitches to the southeast, disappears beneath the Pliocene beyond
Romany, but is probably continuous with Surakhany. The fresh-water
formation covers most of the field, the unfossiliferous series appearing in
the salt marsh of Kir-Maku. The oil in the upper beds at Romany is
lighter, in the lower beds at Balakhany heavier.

28 OIL FIELDS OF RUSSIA

Bibi-Eibat. This is a dome plunging north-northwest and possibly
beneath the sea. At its crest are two subsidiary parallel domes, one
with its apex on Group XIX, the other roughly on Group XX. Between
them, the shallow minor syncline forms the low hill running out to sea
at Cape Naftalan. Much minor faulting, usually parallel to the major
axis, occurs. The fresh-water beds are exposed around Naftalan where
the best production has been obtained. The beds are very uniform litho-
logically, the sands being fine to medium grained, the former like dust
and known as "gas sands" to the driller, while alternating clay and fine
sand is termed "gas clay." "Water sands" are cemented with lime,
"oil sands" are loose and when saturated with gas and oil are thought
to resemble caviar. The occurrence of hard concretions of sandstone
probably accounts for the removed cementing material.

Ignoring the beds of inspissated oil and gas and oil shows in upper
beds, the first important pay was struck at 280 ft. Other oil sands were
struck at intervals but were exhausted down to 700 ft. before any study
of the field was made. Between here and 640 m. (2100 ft.) were twenty
workable sands with a total thickness of 120 m. (390 ft.) . Water sands
were few and it was only below 2600 ft. that the predominance of sands
made water-shut-off of such importance. Water occurs in all sands
and made the marginal plots unprofitable.

Binagady, Khurdalan, and Puta. These areas are geologically much
alike. Oil is obtained from the unfossiliferous series, which are folded
into much faulted anticlines. The oil is heavy. Binagady became
prominent as a producer during the war; the other fields are classed
in the "hand dug" production.

Holy Island. The Pleistocene beds here rest directly on the unfossil-
iferous beds, very much disturbed, with the Spirialis horizon just show-
ing to indicate the succession. The fold is an elongated dome with the
major axis northwest; it is asymmetrical with overfolded side in places.
It is much faulted and there is evidence of other domes outside the de-
veloped area (in the northern part of the Island) .

Seepages occur at the southern end of the anticline and in the central
salt marsh and mud volcanoes, etc. along the crest. The oil has infil-
trated into the Pleistocene and has formed Kir deposits in the sandstones
of the northeast part of the fold. This part has been developed with
the drill, the wells giving 800 poods daily from 1300 ft. The specific
gravity is 0.944.

Grozny. Outside the Apsheron Peninsula, the most important field
is Grozny. Here are two folds. The old field is an elongated asym-
metrical dome, slightly bulging outwards on its steep side, accompanied
with dip faulting, which marks out distinct provinces as regards water
and richness of pay. Dips on the north vary from 40 to 90; on the
south, from 20 to 30 and flatten out at the ends to 6 to 15. The
length is 9 mi. west northwest.

A. BEEBY THOMPSON AND T. G. MADGWICK 29

The new Bellik field is a nearly symmetrical fold and lies to the east
of the old field.

As shown by the columnar section, Table 2, the beds are of Miocene
age, the oil occurring in the Chokrakian (transition Mediterranean-
Sarmatian), and they do not outcrop. Just at the apex of the old field,
the overlying Spaniodontella beds are exposed. The oil occurs in
sandstones associated with shales, sandy clays, limestone, and dolo-
mites; whether in situ appears doubtful.

Maikop. Here oil occurs in beds of Upper Oligocene age, in a suc-
cession of shales, marls, and sandy beds. Beneath is a thick mass of
foraminiferal marls, above are the Mediterranean-Sarmatian beds of the
Chokrakian limestone. The Tertiaries lie unconformably upon denuded
Cretaceous rocks in the oil-field region of Shirvansky, no Eocene beds being
interposed, but farther west these latter appear. The oil sand is a
narrow strip down the dip and probably represents a former river bed.
It is sealed, by overlapping against some of the Cretaceous islands
penetrating the foraminiferal marls; the dip of the Tertiaries is 10.
The Pioneer well was able to show a yield of 375,000 bbl. from the shallow
depth of 281 feet.

About 140 km. (87 mi.) westward lies Kudako where the first Russian
gusher was struck, in February, 1866, at a depth of 70 ft. with a reported
yield of 1,000,000 poods (120,500 bbl.). Subsequent wells reached
700 to 1050 ft. under conditions similar to those at Maikop. The
specific gravity of the oil was 0.840 to 0.865. Another small pool was
opened by Tweddle in the early eighties, by the river II, with production
from both the oil sand and the overlying Chokrakian, the latter being
a heavy oil.

Berekei. Here a much faulted anticline occurs involving much the
same horizons as at Maikop, but oil occurs in many horizons and, being
associated with hot water, may come from some depth. Its specific
gravity is 0.868.

Cheleken. The actual productive area is in the southwest corner of
the island, where there is a dome with its major axis northwest, but with
dips southwest of 15 to 50 and northeast of 18 to 20. It is much
faulted parallel to the axis and the steep side is involved in a trough
fault, whence the best production of late years has been obtained. The
dome itself has produced for many years. Toward the center of the
island, the larger dome of Chokrak has many oil indications but the
productive Pliocene beds have been denuded and the underlying
continental formation of unknown age is exposed.

Emba. Here the surface is entirely covered by Pleistocene beds
and the subsoil structure can only be explored by the drill. Salt masses
occur and the detailed geology has not yet been worked up.

Ferghana. The Syr-Darya (Jaxartes) valley is a Cretaceous-Tertiary
basin lying between the western continuation of the Tienshan mountains

30 OIL FIELDS OF RUSSIA

and the Zarafshan-Chain. Oil indications occur in the margins of the
Cretaceous rocks and are associated with rather complex secondary
anticlinal structure often partly concealed by Pleistocene rocks. The
worked fields of Chimion are on the southern margin.

DRILLING OPERATIONS

Owing to the highly disturbed and unconsolidated sediments in the
Baku oil fields it has been found impossible to adopt the standard
American cable system or even the rotary. The need for wells having
exceptionally large initial and completed diameters is due to the neces-
sity of excluding waters and penetrating swelling and caving ground
during progress, as well as to permit of the extraction of oil by bailers;
consequently, the " stove-pipe " system is mostly employed. Initial
diameters of 36 to 40 in. (91 to 101 cm.) are usual when ultimate diam-
eters of 12 to 14 in. are desired at a depth of 2000 ft. Massive surface
gear is necessary to manipulate columns of such size and tools of
such weight. Engines or motors of 50 to 60 hp. are usually employed to
drive the rigs.

Because of the enormous volume of sand expelled or raised with the
oil, the drilling difficulties of the Baku oil fields rather increased with the
development of the field, thereby neutralizing the favorable influence
of natural improvements that were gradually introduced. Usually
from 1 to 3 years were occupied in drilling the deeper wells, and their
cost, in pre-war days, was not less than $25 a foot; nearly 50 per cent,
of this sum was for the casing alone.

Amid such disturbed and loose sediments, no water-flush system
was permissible as the water freely entered partly exhausted sands and
found access to all surrounding wells, from which it was bailed. Away
from the old fields, as at Surakhany, where a considerable thickness of
more consolidated, non-petroliferous (or slightly so) beds have to be
penetrated before the normal loose, oil-yielding facies is reached, rotary
drilling has proved successful and greatly accelerated progress has been
made.

The system in vogue is the free-fall which, being operated by rods
from the walking beam, transmits a positive action to the drill, enabling
tools to be rotated against a resistance and the motion of underreamers
to be positive. Wire-rope cable drilling has been successfully performed
in the Baku oil field under skilled direction, but the risks are great and
the ultimate speeds never exceeded those of the free-fall drilling system.
Rarely could more than a few feet be left unlined without danger, and
often 70 per cent, of the time was occupied in the maintenance of the
freedom of the column of casing to insure its descent of only a few hundred
feet.

A. BEEBY THOMPSON AND T. G. MADGWICK 31

Unlike Baku, the Grozny strata are much more compact, and al-
though many of the productive beds are unconsolidated sands which are
freely expelled with the oil, the intervening beds hold up sufficiently to
permit the employment of standard wire-line cable drilling, consequently
quicker work results. The pre-war cost of wells 3000 ft. deep did not
exceed $12 per ft., of which about 50 per cent, was for the casing. In
the Ural-Emba oil field, where great thicknesses of gypsum and salt have
been pierced and the ordinary sediments are fairly consolidated, the
rotary drill has proved highly successful.

Many of the companies operating in the Maikop oil field used the old
free-fall system, others used Galician rigs, but in the shallow field portable
Star rigs were found to accomplish just as fast work as the others, while
making unnecessary the use of expensive derricks, and lengthy dismant-
ling and re-erection of plant on the completion of each well.

Cheleken conditions resemble those of Baku and wells entail long and
costly work to complete.

The main feature distinguishing Russian from American practice
is the design and employment of positive tools, owing to the great diffi-
culties of dealing with loose sediments and the enormous financial losses
sustained by the abandonment of a well that has required several years
to make and on which perhaps $50,000 or more has been expended. Of
exquisite design and workmanship, many of the fishing tools cost thou-
sands of dollars, and they were invariably used on solid or hollow fishing
rods, which permitted the most delicate handling and certain release if
they failed in their object. All fishing rods had a loose collar joint and
feather so that they could be rotated right- or left-handed at will; reliance
was never placed on a trip movement, as is the case with many
American fishing tools. Owing to the heaving nature of the beds, it was
often essential to employ powerful water flushes to free the material
around a lost bit; for this purpose 3-in. pipes were customary.

The enforced use of riveted stove-pipe casing rendered cementations
for water exclusion lengthy and delicate operations, as the failure to hold
water or resist pressure without leakage prevented the simpler American
circulation systems from being adopted. Anything beyond a shoe cemen-
tation made it imperative to fill the casing with earthy matter and its
subsequent extraction was often as difficult as drilling a new well in
most countries.

PRODUCTION METHODS

During the early history of the Baku oil field, practically all wells
penetrating a virgin sand body of any importance flowed so violently
that their effective control was practically impossible. Enormous
masses of sand mixed with boulders and pieces of rock were often ejected
for days and weeks, rendering approach to the well dangerous. Single

32 OIL FIELDS OF RUSSIA

wells have given for weeks as much as 10,000 tons daily of sand mixed
with an equal weight of oil, and all objects placed to obstruct or deflect
discharge were destroyed or perforated in a few hours. Usually hard-
wood blocks or chilled, cast-iron plates, 12-in. thick, were pushed over the
mouth of the well some distance above the ground, and the vertical jet
was thereby deflected horizontally. These " fountain shields, " as they
were termed, were replaced as they became destroyed.

The wells themselves did not escape damage as the casing was often
torn to shreds, each soft rivet causing the initiation of a vertical rifling
that extended upwards as the sand-blast action continued. In certain
regions, when excessive gas pressures were encountered, well after well
was sunk and destroyed after a few days, eruption before the pressure
was relieved sufficiently to permit normal development. Occasionally,
sand only or oil-soaked clay would be expelled for days, or even weeks,
before oil entered or deepening could be resumed. On the cessation of
flowing, the wells were often in a delicate condition and remunerative
yields, free from water that entered the damaged casing, could only be
secured by the maintenance of a high head of oil that, usually, exceeded
the static head of upper water sources. Such a condition could only be
effected by keeping the well clear of sand at the bottom and so facilitating
the entry of oil. A little water that practically always gained admission
nd collected near the base of the well not only served to compact the
sand, but greatly impeded the entrance of oil; consequently, the water
had to be abstracted at regular intervals. The only method of handling
such a condition was by bailing, and the scientific application of this
principle reached a high degree of efficiency in the Russian oil fields.

Bailing drums 16 ft. in circumference were driven by engines develop-
ing up to 150 hp. each, and velocities of 1500 ft. per min. were common.
Single bailers up to 7.5 bbl. capacity were used in large-diameter wells
of great yields and productions up to 2000 bbl. daily were raised by this
method. The mean cost of bailing Baku wells in pre-war days, averaging
120 bbl. a day each, was under 20 c. per bbl. but the large yielding wells
individually would cost but a fraction of this to bail.

The only other process for raising oil that met with success under the
early Baku conditions was the air-lift. In wells of small diameter with a
high level of liquid where bottom bailing had to be frequent to remove
water and sand accumulations, the air-lift proved very successful. Al-
though the cost of operating the air-lift greatly exceeded that of bailing,
the excess costs were often repaid many times by the augmented yield.
Emulsions in some cases gave trouble, but usually sandy water and oil
were alternately discharged at more or less regular intervals during con-
tinuous or intermittent working as the case might be. In low-level
wells all discharges were intermittent in operation; in high-level wells,
the discharge was continuous.

A. BEEBY THOMPSON AND T. G. MADGWICK 33

With the gradual reduction of gas pressure on the Baku oil fields,
opportunities arose for the use of pumps in the less sandy wells, but the
constant need for renewals of cup leathers, barrels, or plungers has caused
the system to be unpopular. The oil is never quite free from sand and,
as the density of the oil is light and sand quickly sinks in the column, there
is a tendency for the plunger and valve to become choked up if left idle
for a few minutes.

There are fewer objections to the use of pumps in most of the other
oil fields of Russia but while the period of intermittent flowing continues
bailing is preferred in order to keep the well clear of sand. Deep well
pumps are used in the Grozny and other fields when the wells have settled
down.

OIL-FIELD YIELDS

The Baku oil fields are by far the richest yet discovered. Not merely
are the loose uncemented sands capable of high absorption, but they are
plentifully distributed throughout a depth of several thousand feet of
sediments and often reach a considerable thickness. Thus, within the
confines of a single plot, a dozen highly productive sands may be struck
aggregating several hundred feet in thickness. A selected plot at Bibi-
Eibat has yielded nearly 2,500,000 bbl. per acre, and the whole operated
area of 250 acres in that field has produced over 1,500,000 bbl. per acre.
Even the greater Balakhany-Saboontchy field of Baku, aggregating about
2600 acres, has yielded fully 500,000 bbl. per acre and is still capable of
enormous collective production, though the individual output of wells is
now small. Enough oil has been abstracted from this field to cover the
whole area to a depth of 63 ft. neglecting entirely the many millions of
cubic feet of gas with its contained gasoline that has been lost.

The influence of interference and the process of exhaustion is, perhaps,
best illustrated by the steady decline of initial productions of new wells.
Between 1892 and 1896, the first half yearly output of new wells was
around 108,000 bbl. (600 bbl. per day). In 1912, this had fallen to
15,000 bbl. (80 bbl. per day) and during the same interval the ultimate
yield had sunk from 675,000 bbl. per well to about 225,000 bbl. In
1895, the average annual production of wells at Baku was 75,000 bbl.;
in 1909, the average had been depressed to 30,000 bbl. although in the
same period wells were on an average 60 per cent, deeper. In the Bibi-
Eibat field, footage ceased to increase or even sustain production after
1904 when the zenith of production was attained in that region.

Civil disturbances for some years prior to the war and general dis-
organization since make any estimates and predictions of little value.
The fields are still capable of giving enormous quantities of oil, and their
present potential capacity is probably between 25,000,000 and 20,000,000
bbl. a year. Much local speculation is aroused as to the results that will

VOL. LXV. 3.

34 OIL FIELDS OF RUSSIA

attend the drilling of reclaimed plots in Bibi-Eibat bay, the Great Lake
of Romany, and large reserved areas surrounded by old producing plots.

An unusual amount of scientific interest surrounds the obsequies of
these famous Baku fields, and it would be a world's loss if trustworthy
data were not kept for the benefit of our successors. The final phase is
apparently in sight, as what appears to be basal water has been pene-
trated beneath the great oil-bearing ^series. Considerable thicknesses
of water-bearing sands exist, but whether these are underlain by other
oil-bearing sands it is difficult to say. One would surmise not, and there
is just the possibility that the upper riches may be partly due to the ex-
pulsion of the former oil contents of these beds by water.

At present, the dregs of these vast oil fields are being mainly secured
through the medium of water which has percolated into the disrupted
and badly disturbed beds from which sufficient solid matter alone has
been flung by thousands of wells to raise the oil-field surface many feet.
From the thousands of wells a mixture of oil and water is constantly
being raised, but both the oil and the water contents are being reduced.
Some areas no longer yield water at all where formerly expensive
measures had to be undertaken for its exclusion; here the least oil is now
obtained as natural filtration without the aid of gas or water is in-
significant. At other points the static head of the liquid is gradually
falling, and unless the lower water is admitted the whole field may be
eventually dried up. No synclinal or edge water that cannot be over-
come by bailing encroaches on the exhausted upper oil strata, so that
the chief migration of oil may have been vertical rather than lateral.

The Surakhany field to the east of the Balakhany-Saboontchy area
has now become the most interesting in the Baku zone. Years ago, the
deep development of the oil series was predicted by geologists and their
predictions have been verified. Enormous volumes of natural gas were
obtained from shallow fine sands in the area and the product was piped to
the oil fields for fuel. At increased depths, gushers of white oil, specific
gravity 0.785, were struck in similar sands, and there is now little doubt
that they represented a filtration product of migration from the
underlying normal series.

Large gushers of the typical Baku grade oil have been struck in the
Surakhany area where an active development was in progress until the war.

In the Grozny oil field, wells have given very substantial productions
along a belt of many miles. No area has excelled in productivity the
original plot on which the first well was drilled, about 1897. This point
corresponded with the maximum elevation on the pitching anticline and
attracted attention by its surface manifestations. This plot has yielded
over 320,000 bbl. of oil per acre. In 1914, Grozny yielded 10,500,000 bbl.
from about 8000 acres. The field has given about 150,000 bbl. per
acre and is still far from exhausted. After an initial flow, wells continue

A. BEEBY THOMPSON AND T. G. MADGWICK 35

to yield normally. A typical well yielding an ultimate production of
80,000 bbl. gives about 50 per cent, of its total production in the first
year, 22 per cent, in the second, 15 per cent, in the third, and 1% per
cent, in the fourth.

Exceptionally good results were obtained on the Bellik oil field,
discovered in 1912. It is really an extension of the old Grozny oil
field or a parallel fold. Pioneer wells gave large and sustained flows,
and an important field is likely to result, possessing the Grozny
characteristics.

No detailed statistics are available concerning the important Emba
oil field of the Uralsk. Large flowing wells were struck in some number
near Dossor and considerable shipments of oil were made to the Volga.
There is every indication of a large and useful field being opened up.
The Island of Cheleken, off Krasnovodsk, gave its maximum output in
1912, when 1,500,000 bbl. were reported. In 1913, the production was
under 1,000,000 bbl. and the fall continues. Activity was confined to the
Ali Tepe sector, which area seems to have passed its best days. Holy
Island has attracted sporadic attention and appears to justify more.
One company operates and produces about 800,000 bbl. a year when
conditions are normal.

The small field near Shirvansky, known as the Maikop, has yielded
over 4,000,000 bbl. of oil; a production of about 250,000 bbl. a year is
still maintained despite the fact that the area has not been greatly
extended.

Little information is forthcoming about Ferghana oil field of Turkes-
tan. At one time the production reached 450,000 bbl. a year and the
oil found a ready local sale in that part of the world. At Maili Sai, no
further drilling has been undertaken.

Innumerable abortive or uncertain tests have been made in the
Caucasian oil belt. Some were undertaken at a time when nothing
short of 500-bbl. wells attracted any interest at all. At many spots produc-
tions have been obtained that would pay well in any other part of the
world. All along the Caspian Sea littoral, from Baku to Derbent,
there are frequent and encouraging indications of oil. At Berekei, a
little northwest of Derbent, about 500,000 bbl. of oil were taken from a
field in which 2000- to 5000-bbl. wells were struck; but water troubles
eventually drove away nearly all operators. At Kaikent, a large gusher
was struck in an initial effort, although all subsequent wells failed.
Around Baku at Binagadi, a much despised region left for years to peas-
ants to develop by primitive methods gave, in 1913, 1,750,000 bbl. of
oil and has since exceeded 4,000,000 bbl. a year. At Puta and Kharda-
lan, a thriving industry developed as a result of hand-dugs sunk into
the outcropping oil sands and an output of 1,700,000 bbl. resulted in
1914. Drilling would yield very different results.

36 OIL FIELDS OF RUSSIA

Miles of territory flanking the Caucasus foot-hills that fringe the
valley of the Kura are capable of remunerative development. In some
places small wells, still flowing, testify to past efforts, and at many places
the peasants satisfy all local wants by sinking shafts into outcropping
oil sands.

At Ildohani in the Tionct valley, near Tiflis, productive wells were
sunk that flowed oil of light density in which crystals of wax separated;
at other places in the same district fruitless experiments were made with
antiquated plants where modern methods might have succeeded. At
Chatma, near the River Jora, there are numerous indications of oil and
interesting structures.

Miles of the Black Sea littoral and Taman peninsula are potential
oil fields; indeed, many dozens of productive wells have been sunk in
that region where such stupendous mud volcanoes are in evidence.
Russian geologists have estimated that there are fully 30,000 sq. mi.
of interesting undeveloped oil land in Russia and this is probably no
exaggeration.

CHIEF RUSSIAN OIL FIELDS

The main oil fields of Russia, in the order of their relative importance,
are as follows :

APPROXIMATE APPROXIMATE
PRODUCTION, PROVED AREA,
IN BARRELS ACRES

Balakhany-Saboontchy field, |

Romany, V to 1918 1,597,690,000 J 2,600

Bibi-Eibat field, J 1,000

Surakhany field, to 1918 54,920,000

\ ' I to
ik field, )

Binagadi, to 1918 22,620,000

Khurdalan ^

Puta I to 1917 9,082,000

Berekei J

Holy Island, to 1918 5,562,000

oj U Dossor, etc., to 1917 ...... 8,575,000

= i

0) *S

J3 3 Cheleken Island, to 1917 .................... 7,317,000

I c Ferghana field, to 1917 ...... ............... 3,620,000

Maikop, to 1917 ........................... 4,750,000

Baku

I
\

Grozny { to 1917 Lttd . . . . . . - 139,858,000 8,000

DISCUSSION

TABLE 4. Approximate Production, in Thousands of Barrels (8.3

Poods to a Barrel)

Previous to
1914

1914

1915

1916

1917

1918

Baku Oil Fields
Balakhany-Saboontchy
Romany

| 1,427,950

12,400
7,380
1,980
5,300

| 93,800 {

845
2,870

5,670
2,680

132,000

8,700
6,200
2,650
712
840

10,600
1,028

2,000
482

602
217

31,800

9,550
7,270
3,930
844
930

9,260
1,350

1,990
915

482
241

29,000

10,800
11,600
4,160
820
1,180

8,280
4,100

1,870
241

362
241

24,600

7,350
11,150
3,560
844
832

6,620
4,820

1,870
242

201
241

12,500

3,440
6,300
940
362

5 gushers
burning 9
months

Bibi-Eibat

Surakhany

Binagadi

Holy Island . . .

Khurdalan, Puta, etc. . .
Terek
Grozny field

Bellik field

North Caspian
Emba oil field

Kuban
Maikop

Asiatic Russia
Cheleken

Ferghana

DISCUSSION

ARTHTJK KNAPP, Shreveport, La. From this paper one would be
led to believe that the American system of drilling was not a success in
Russia; I spent two years in the Baku field and know that this is not true.
The first rotary rig that I know of was sent over there in 1913. The
Russian engineers were so opposed to the use of the rotary that it was not
until 1914 that a well was drilled using American methods throughout.

The first rotary hole was drilled 1800 ft. (548 m.) in about three
months and offset a well that took 2J^ years to drill by the Russian
method. The Russian method used about 120 tons of casing while the
American method used only two strings, 10 and 6 in., with a saving of
from $75,000 to $80,000. During the next two years, between eighteen
and twenty rotary wells were finished in the field. In every case there
was a saving of from 20 to 60 per cent, on casing and from 30 to 50 per
cent, on time and labor.

The fundamental difference between the Russian and American
systems of producing oil is that in America we try to keep the oil for-
mation from moving, by the use of screens, where necessary, while the
Russian engineer does everything he can to produce a large quantity of
sand. The drilling with the rotary is about the same as the drilling in
the Midway field in California.

38 OIL FIELDS OF RUSSIA

The Russian engineers have opposed the use of deep well pumps as
a means of producing oil. I installed an ordinary 2-in. pump in a well
that produced about 12 bbl. of oil and increased the production to 24 bbl.
on the beam. Our statistics showed a saving of 50 per cent, over bailing.
Another company under English control put about twelve wells to
pumping on jacks. They were run for some time and the cost compared
with the same kind and number of wells being produced by bailing. The
pumping wells used about 25 per cent, of the steam that was required by
the bailing wells. The labor costs were 12 per cent, and the repairs and
upkeep 5 per cent, of the bailing costs.

The deepest wells in the Baku fields at the time that I was there
were about 3000 ft. deep. They took at least three years to drill by the
Russian system and cost about $125,000. Only one out of three of the
Russian wells at this depth was a successful producer. The uniform
success of the American system was very much in its favor. Out of the
fifteen or twenty wells drilled during 1914-15, only two of the American
wells were lost.

The American rotary system is being very rapidly adopted. When
the war stopped imports the Russians tried with good success to make
rotaries of their own. The rotary may never entirely supplant the
Russian rig but it has been a great success and has come to stay in
Russia.

Mr. Thompson's paper is the only one that I know of that brings
our knowledge of the Russian oil fields up to date. It is a valuable
addition to our literature.

A. BEEBY THOMPSON (author's reply to discussion). Mr. Arthur
Knapp's remarks, without some qualification, are apt to be misleading.
In the past, the leading oil companies of Baku have spent large sums in
experimenting with American plant and have offered high rewards to any
successful operator who could increase speeds and reduce costs but a small
percentage. The best operators were sought and every facility granted
them but until just before the war no improved results had been achieved;
indeed, until the modern heavy type rotary was introduced the problem
appeared hopeless. Any driller who could have saved but 20 per cent, in
time or costs of drilling wells in the rich Baku oil field could have made
contracts that would have yielded him a fortune in a few years, as the
time factor in such congested areas meant so much to operators. Where
wells are drilled within 100 ft. or less of each other and a few square miles
are perforated by thousands of wells, it is almost inconceivable that
rotary flush drilling could be uniformly successful, for the mud enters the
loose, partly exhausted sands and follows channels of flow to neighboring
producing wells. Attempts in Bibi-Eibat many years ago caused many
wells to turn to mud and water when the rotary penetrated one of the
main sands from which the wells were drawing oil.

DISCUSSION 39

Rotary drilling has proved successful only in areas outside the con-
gested fields where great thicknesses of uninteresting beds have to be
pierced before the productive oil series is reached or where oil occurs in
more compacted strata. Any operator able to save $75,000 worth of
casing and nine-tenths of the time of drilling in proved areas could within
a few years be a wealthy man.

The Russian engineers have not opposed pumping on principle, as in
Grozny and Maikop pumping has been conducted for years. As far
back as 1900, the writer made persistent efforts to use pumps in the Baku
oil fields but the large quantities of sand accompanying the oil made their
use impossible. In no case could a highly productive well be pumped for
more than a few hours without the pump being choked by sand and the
cups or plungers being cut to pieces. Induced flows through the pump
sometimes brought in sufficient quantities of sand to fill hundreds of feet
of the tubing. At that time no 12 or 24 bbl. well was accepted and prob-
ably 100 bbl. was the minimum payable yield. Conditions are quite
different today and there are many Baku properties where the slowly
infiltrating oil is sufficiently free from sand to enable grouped pumping to
be conducted. In the past, the output of a well fell off to an unpayable
yield unless the sand that entered the well was constantly being removed,
by bottom bailing.

40 PETROLEUM IN THE ARGENTINE REPUBLIC

Petroleum in the Argentine Republic

BY STANLEY C. HEROLD,* TULSA, OKLA.

(New York Meeting, February, 1920)

AT THE present time five localities in the Argentine Republic are
known to bear direct evidences of the presence of petroleum. The
segregation of these localities is more or less arbitrary inasmuch as minor
indications may be found to extend from one locality to the other at no
regular distance apart, especially in the northern and western part of the
republic. These localities are listed as follows: North Argentine-Bo-
livian region, Salta-Jujuy district, provinces of Mendoza and Neuquen,
Comodoro Rivadavia, and the Gallegos-Punta Arenas region.

Economic conditions attract us to the possibilities of developing these
and other regions of countries in the southern hemisphere. Develop-
ment work will, naturally, be undertaken first in such localities as present
direct manifestations of the presence of petroleum; "hidden fields"
may exist, but, unless discovered by accident, their development will be
left to the last.

The problems to be solved in the development of the petroleum
resources of the Argentine republic are mainly of stratigraphy, structure,
and transportation. We are not here concerned with the unfavorable
climate of the countries to the north in the tropics where, for us of the
"far north," life hangs by a thread ready to be severed by a mosquito,
gnat, or tropical germ.

NORTH ARGENTINE-BOLIVIAN REGION

The North Argentine-Bolivian region has already been described by
the author. 1 Geographically and geologically this is admittedly one field
extending from Argentine into Bolivia. It is not necessary to repeat
here the various conditions pertaining to this field, though the summary
may be quoted as follows:

Extending from northern Argentine northward into central Bolivia is a belt of
petroleum seepages. On account of the remoteness of the district it has, heretofore,
been little considered by oil operators. The regional geology is comparatively well
understood but the local features have not been carefully detailed.

Development work in the past has been done on an unscientific basis and has led
to failures. At the present time, access to the region is somewhat difficult but no

Chief Geologist, Tulsa District, Sinclair Oil and Gas Co.
i Trans. (1919) 61, 544.

STANLEY C. HEROLD 41

serious problem would be encountered in improving the conditions. The nearest
railroad terminal is at Embarcaci6n, 114 mi. (183 km.) south of the Bolivian border,
or 72 mi. (116 km.) from the nearest manifestation of petroleum in natural springs.

The oil is of high quality and the seepages occur in creek beds along the Sierra de
Aguaragiie fault, and at other isolated places.

Native labor is good and government policies are sympathetic toward foreign
exploitation.

Though the structural features of the region, as a unit, have been worked out by
reconnaissance surveys, there still remain many local sections upon which no detailed
study has been made.

Several small areas have been proved unfavorable for production, though the
region as a whole cannot be condemned on this account.

Since writing the above there has been no further development in this
district, to the author's knowledge, though individuals have had their
geologists there.

THE SALTA-JUJUY DISTRICT

The Salta-Jujuy district lies to the west of the foregoing area, north-
west and north of the town of Salta, extending into Bolivia. There may
be no logical reason for separating these fields except that the latter lies
in the mountainous and somewhat inaccessible part of the country. The
stratigraphy of one is closely related to that of the other. Seepages are
small and widely scattered, of high quality oil, and not of continuous
flow, for heavy rains may either temporarily efface or bring to light slight
showings of petroleum, depending on local conditions.

The structure of the district is rather complex due to the folding
and faulting of the strata lying on the side of igneous formation protruded
in the Andes uplift. As the surface is made up of steep mountains and
narrow gorges largely, there is small probability of extensive develop-
ment. The seepages occur along the exposures of beds dipping at high
angle and along faults.

PROVINCES OF MENDOZA AND NEUQUEN

These two provinces lie on the eastern flank of the Andes Mountains
due west from Buenos Aires and adjoining the Republic of Chile. The
province of Mendoza is traversed by the trans-Andean railway which
extends from coast to coast. Seepages, generally of tar or asphalt and
heavy oil, extend in a north-and-south line along the frontal ranges, paral-
leling the main trend of the range. The author made but a casual observa-
tion in this district and is therefore not competent to enter a detailed
discussion of stratigraphic conditions. The main features are beds of
steep dip and numerous faults. Some development has been under-
taken in the past but up to autumn of the year 1917 no success had been
met. The area has its possibilities.

42 PETROLEUM IN THE ARGENTINE REPUBLIC

COMODORO RrVADAVIA

At Comodoro Rivadavia is situated the only successfully developed
oil field in the Argentine Republic. It is located in the southeast corner
of the territory of Chubut along the Atlantic seacoast, immediately north
of the town of Comodoro Rivadavia, on the Gulf of St. George (San
Jorge) at approximately latitude south 45 45' and longitude west 67 20'
from Greenwich. From Buenos Aires, the field lies in a direction of south
30 west, 1164 mi. (1875 km.) distant, as the ships sail.

The area includes the reserved land of the Argentine Government of
5000 ha. (12,050 acres), 5000 by 10,000 m. along the coast covering the
town of Comodoro Rivadavia itself. Furthermore, it includes various
areas adjoining this reservation to the north, west, and south. Three
properties were producing petroleum in the latter part of the year 1917:
namely, the government reservation, the Compania Argentina de Como-
doro Rivadavia, and the Astro property, the latter situated about 20
km. north. Many claims or concessions have been taken up by local
parties, some of which appear to be favorable for production.

Previous to the accidental discovery of oil by drilling for water there
were said to be absolutely no signs of the existence of oil or gas under the
surface in this region. The domestic water supply of the town of Como-
doro Rivadavia was very poor and in such condition as to render the
district unhealthy. In the year 1908, the Argentine Government sent a
drilling outfit there to prospect for water, a site having been chosen
opposite the bank building in town. No water was encountered so
the drill was removed to a place 3] km. north. Drilling proceeded
until a strong flow of gas was encountered and later a gusher of oil at
1770 ft. (540 m.) below sea level. The well was'probably not over 70 ft.
above the sea.

Since discovery, drilling has been continued with more or less regular-
ity until, in the latter part of 1917, about sixty wells had been put down
on the reservation, a fair proportion of which proved successful. Water
is now brought from the hills to the west through pipe and supplies all
requirements.

Within the government area, at least three sedimentary series exposed
at the surface have been differentiated. The lowest stratum exposed is
that of a white, soft, tufaceous formation lying at the base of the hills
immediately to the north of the oil field. Traces of carboniferous matter
have been found in this formation but no fossils capable of recognition
were on record at the time of the author's visit. Its age was considered
to be Lower Eocene or possibly Upper Cretaceous. About 50 ft. of the
series is exposed.

The next younger formation is a series of sandstones and shales.
The sandstone is light brown in color, soft, and easily eroded. Sand

STANLEY C. HEROLD 43

grains are of medium size. Beds vary in thickness from 10 to 50 ft.,
bedding planes well defined. The shale is also light brown where exposed
and very soft. The entire thickness of the series is approximately 200 ft.
Fossils of this formation were considered to be of Eocene Age.

The third and youngest stratified series is the so-called "Patagonia"
series, a formation composed largely of soft, light brown, thinly bedded
sandstone. Some shale occurs. It is this formation that stands in high
cliffs to the west of the field. At least 300 ft. of the series is exposed in
the immediate vicinity. Fossils are very abundant. They are prob-
ably of Oligocene age.

In addition to these stratified deposits there is a great amount of
chert, water-worn pebbles lying loosely on the ground above the Pata-
gonia series and particularly along the beach. These pebbles are pre-
dominantly of yellow, red, green, and black colors and undoubtedly
were transported from a distance.

The formations below the tuff penetrated by the drill are mostly
gray shales and sandstones, the hardness of which varies somewhat in
the different strata. They may be Lower Eocene or Upper Cretaceous.

The beds at the surface lie at a very low angle, somewhat similar
to conditions in the Mid-Continent fields. The normal dip is toward
the southeast with sufficient undulation to produce flat dome struc-
tures with closures in contours on the northwest. At the close of
Patagonia time, a gentle but extensive uplifting took place throughout
the entire region, leaving the strata almost horizontal, producing the
great "pampas," or high plains, to the west toward the Andes. Evi-
dently little, if any, lateral pressure was exerted upon the strata, for
they appear little disturbed except for their elevation. The sea and
rains have ravaged the coast line, leaving a shelf with low relief along
the coast; it is on this shelf that we find the development of the field.

The oil is found on the above-mentioned domes in a sand that lies
conformably to the series at the surface at a depth close to 530m. (1740ft.)
below sea level. The texture of the sand seems to vary considerably,
producing non-porous parts sufficiently tight to exclude the oil. For
this reason oil is not always encountered as soon as the oil formation is
struck. In some wells it was reported that oil was not encountered
until a depth of 580 m. (1900 ft.) had been reached. Overlying the oil
series is a soft bluish-gray shale. The age of the series was thought to
be Upper Cretaceous, though this was not certain. Water has been
encountered but no difficulty is experienced in shutting it off.

The wells of this field have been drilled by a combination of the rotary
drill to a depth of 462 m. (1515 ft.) and the Fauck system with rods to
the oil strata. The rigs are of the closed-in type, covered with sheet
iron on four sides to the top. They must be heavily guyed to prevent
damage from strong winds prevailing during certain seasons. At the

44 PETROLEUM IN THE ARGENTINE REPUBLIC

time of the writer's visit, two American rigs had recently been built to
use cable tools in combination with the rotary outfit. As far as they
had been used, they were making an admirable record compared with
the rods. It seems quite necessary to use the rotary for the upper
part of the hole, as the walls are subject to caving. Strong flows of
briny water are encountered at 350 m. (1150 ft.) and at 435 m. (1428ft.).
Gas is often struck at 150 m. (492 ft), and at 400 m. (1312 ft.).

In August, 1917, twenty-five wells were producing 4000 bbl. of oil
per day and an average of 60 m. (195 ft.) of new hole per day was being
drilled. The oil is heavy, about 18 Be", on an average, black in color,
with a low content of gasoline. There is a small refinery on the ground
for extracting the gasoline. The refuse is returned to the storage tanks
for shipping to Buenos Aires, where it is used by industrial plants as
fuel. The government maintained a fleet of four tankers at that time.
Loading was often done with difficulty on account of lack of harbor
facilities, since the Gulf of St. George is quite open to the Atlantic.
Although but twenty-five wells were producing, about thirty-five others
had been drilled and had either been dry, lost holes, or abandoned as no
longer profitable to operate. It is understood that this record has been
considerably improved since that time.

A fair proportion of the territory can be surveyed in detail, as is
being done in the Mid-Continent field. The most favorable localities
may therefore be selected for the drill with a minimum of failures.
Stratigraphic conditions are favorable for a considerable extension of
present known producing area. Transportation presents little difficulty,
since the field adjoins the sea and market conditions are capable of great
expansion; all oil not needed by the industries in Buenos Aires may be
devoted to use in oil-burning vessels, which would call if fuel were available.

GALLEGOS-PUNTA ARENAS REGION

At the southernmost section of the continent is located the Gallegos-
Punta Arenas region. In addition to the well-known gas springs near
the town of Punta Arenas, the manifestations extend northward to a
district due west of the port of Gallegos. In the latter locality, the
streams are reported by competent observers to be carrying small quanti-
ties of crude oil toward Lake Blanca. The author has not studied this
region, so is unable to give information regarding conditions and possi-
bilities of development.

DISCUSSION

THE CHAIRMAN (E. DEGOLYER, New York, N. Y.). The production
of petroleum in the Argentine is entirely in the hands of the government.
Some years ago, in attempting to develop a water supply for the
Patagonian region, the department in charge of drilling brought in a

DISCUSSION 45

gushing well. The president immediately withdrew a considerable
reserve around this well; subsequently, the government reduced the size
of the reserve to 5000 hectares and proceeded to develop the property.
I have studied several of the reports of the Commission that has the
matter in charge, and am not able to determine whether or not it is a
profitable venture for the government, but it seems to have devel-
oped a distinct policy of exclusion. The mining laws, like the mining
laws in most Latin-American countries, practically made no provision for
petroleum. They were a development of the old Spanish mining codes
when petroleum was not recognized as a mineral. In most of these
Latin-American countries, some sort of special legislation has been
required to make it possible for one to go in to develop the petroleum
resources. As the tendency in the Argentine seems to be to keep the
thing in the hands of the government, there is the peculiar condition that
a nation that has no coal fuel, and where fuel is the utmost importance,
seems to be determined to have no oil development either.

S. C. HEROLD (author's reply to discussion). At the present time,
development work is carried on in various parts of the Argentine Republic
by several distinct companies largely financed by foreign capital, though
one or two have included a fair proportion of local capital. While some
of these operating companies have not brought in producing wells, the
possibilities are particularly good in some instances.

The Argentine Government now has two reserved zones; namely, that
referred to by Mr. DeGolyer at Comodoro Rivadavia at the southeast
corner of the Territory of Chubut adjacent to the coast line along the
Gulf of St. George, and that at Station Plaza Huincul in the Territory of
Neuquen, both of 5000 hectares area. It is understood that a third zone
may be set aside near the Cerro Negro region, Neuquen Territory. The
favored location for work by the private companies has been, so far, near
the zones reserved by the Government. These zones, with their adjoin-
ing lands, are within "Territorial" jurisdiction; as the territories are
controlled from the national seat of government in Buenos Aires, the
national laws providing for petroleum development are the only laws
prevailing. The provinces may have their own departments of mining,
etc., and may detail their laws respecting oil claims so long as such details
do not conflict with the spirit of the national laws; within the territories
no such detail can be worked out.

It cannot be properly stated that there is any intentional exclusion
policy on the part of the country. Any exclusion prevailing is due rather
to that which the Government has failed to do than to what it has
done. We can hardly expect a country that has only reached the
stage of development in petroleum which the Argentine has experienced
to date to have all matters worked out in detail. Capital invested in
that country will, therefore, be exposed to a risk when the day for the

46 PETROLEUM IN THE ARGENTINE REPUBLIC

interpretation of the present laws is at hand. Assurances that are now
generously given will avail little in the interpretation of the law when
there are invested possibly several millions and the coveted fluid is
gushing from the wells.

The Argentine Government's venture at Comodoro Rivadavia would
appear to be profitable. The price of Comodoro crude at Buenos Aires
last November was 100 pesos per metric ton, approximately $6.50 per
bbl. It is improbable that the rate has changed, for the Government has
practically a monopolistic control over the production to date. As the
production of the field is about 5000 bbl. per day, with the actual delivery
of that amount to the market, it is quite obvious that there would be
"something wrong" if there is no profit. As a matter of fact, the books
do show a handsome gain over expenditures. The property is not
handled in a most efficient manner, nor do the men in charge think it is,
for they admit the difficulties of Government control.

PETROLEUM IN THE PHILIPPINES 47

Petroleum in the Philippines

BY WARREN DuPR^ SMITH,* PH. D., EUGENE, ORE.

(New York Meeting , February , 1920)

IT HAS been 5 years since the writer left the Philippine Islands and
while in that country his chief work did not lie in this field, though he has
visited all but one of the localities mentioned in this article. The princi-
pal field studies relating to oil were made by his colleague, Mr. Wallace
E. Pratt. The writer's investigations dealt with the general stratigraphy
and paleontology of the Philippines. With the exception of the investi-
gations made by Mr. Pratt and the writer very little information on this
subject is available.

A number of geologists in the employ of large oil companies have
visited the Islands from time to time but, following the general rule, the
public has scarcely ever been permitted to learn anything of the results.
The writer is indebted to the Bureau of Insular Affairs, Washington, for
late information regarding recent legislation in the Islands relating to
petroleum.

All the known oil seeps, petroleum residues, such as ozocerite, and
natural-gas emanations are associated with Tertiary sediments. The
chief seeps and most promising prospects are located as follows :

1. Bondoc Peninsula (lower end), Tayabas Province, Southeast Luzon.

2. The west coast of the island of Cebu from Alegria north to, and
perhaps beyond, Toledo.

3. Central Mindanao not far from Lake Lanao.

4. The ozocerite veins on the Island of Leyte in the northwestern
part in the vicinity of the town of Villaba.

5. Natural gas from some deep wells in Tertiary shale formations on
the eastern flank of the Cordillera and extending out under the plain on
the island of Panay.

The first mention in geological literature, to the writer's knowledge,
of gas or petroleum in the Philippines is found in the description of the
Island of Panay by the Spanish geologist, Abella, in the year 1890. In
1898, an oil well was being dug on the estate of Smith Bell & Co., an Eng-
lish concern, near the town of Toledo on the west coast of Cebu. In

* Formerly Chief, Division of Mines, Bureau of Science, Manila.

PETROLEUM IN THE PHILIPPINES

sa.

ft,

ts
ts

itii .
m i li i i III 1 1

$$38

s a

WARREN DUPRE SMITH

Sli

JaS-2
"il

-II

.2 ..9

i II

< >s

Throughout th
pelago.
Throughout the
yan Islands,
and Mindanao.
Luzon, Cebu, Le
Batan, Cebu, etc

etc.

alawa
Panay

Luzon

Luzon
wan.

feo
IS

VOL. LXV. 4

r ! f

Hi i

this year, an insurrection broke out
against Spanish rule and the drillers
were driven from the well, which was
abandoned. It is now practically as the
insurrectos left it; that is, choked with
rubbish which would have to be cleared
before operations could be renewed.

About 1910, a number of Americans
became interested in the petroleum de-
posits known to occur on the peninsula
of Tayabas in the southeastern part of
Luzon, and which were apparently un-
known to the Spaniards. Two wells
117 and 300 ft. (35 and 91 m.) respect-
ively, were dug from which a few gallons
of oil were pumped, but nothing has been
done since then, as far as we know.
At the end of 1917, there was consider-
able excitement in the Islands over the
alleged discoveries of oil in the Lanao
region of the Island of Mindanao. The
existence of petroleum on that island
was known to the writer as early as
1908, but he could not visit the localities
owing to the hostility of the natives.

In 1919, an Act was passed by both
branches of the Philippine Legislature,
and approved by the Governor-General
on Mar. 4, providing for the creation of
the National Petroleum Co. This Act
is as follows :

Section 1. A company is hereby or-
ganized, which shall be known as the National
Petroleum Company, the principal office of
which shall be in the city of Manila, and which
shall exist for a period of fifty years, from and
after the date of the approval of this Act.

Section 2. The said corporation shall be
subject to the provisions of the Corporation
Law in so far as they are not inconsistent with
the provisions of this Act, and shall have the
general powers mentioned in said Law and such
other powers as may be necessary to enable it
to drill wells for the development of petroleum
deposits, and to work said deposits and sell the
output thereof.

50 PETROLEUM IN THE PHILIPPINES

Section 3. The capital of said corporation shall be five hundred thousand pesos,
divided into five thousand shares of stock having a par value of one hundred pesos
each, and no stock shall be issued at less than par nor except for cash.

Section 4. The Governor-General, on behalf of the Government of the Philip-
pine Islands, shall subscribe for not less than fifty-one per cent, of said capital stock,
and the remainder may be offered to the provincial and municipal governments or to
the public at a price not below par which the board of directors shall from time to
time determine. Ten per centum of the value of all stock subscribed shall be paid
at the time- of the subscription, and the balance thereof shall be paid at such time as
shall be prescribed by the board of directors. The voting power of all such stock
owned by the Government of the Philippine Islands shall be vested exclusively in a
committee consisting of the Governor-General and the presiding officers of both Houses
of the Legislature.

Table 1 gives the provisional stratigraphic column of the Philippines.
Table 2 furnishes a tentative correlation of the Far Eastern Tertiary
stratigraphy including that of the Philippines. Some of the shales re-
ferred here to the Miocene may belong to the Oligocene. The oil
horizon (there may be more than one) is probably in the Oligocene or
the lower Miocene shales.

Attention is called to an error in the stratigraphic column given by
the writer in one table in an earlier paper and incorporated by Pratt in
one of his. 1 In that table, the Oligocene is given as resting directly upon
a pre-Tertiary complex. The Eocene is well developed in the Philippine
coal fields and is doubtless to be found in the oil fields as well as in the
coal fields, though perhaps not so extensively.

In view of a prevailing opinion that these islands are largely volcanic,
it should be pointed out that there are large areas where the only surface
rocks are sediments and other areas where volcanic rocks form a veneer
over the underlying Tertiary sandstones, shales, and limestones. In-
trusive diorite is found near the center of many of the large land masses
and more rarely intrusive granite, andesitic and diabasic intrusive are
also found in many places near the borders of the masses.

The section made by the streams flowing eastward from the cordillera
of the island of Panay affords, perhaps, as clear a view of the sequence
of strata comprising a part of the Tertiary as can be obtained anywhere
in the Philippines. The dominant formation is shale with thin-bedded,
intercalated sandstones of which there are some 15,000 ft. (4572 m.)
along the Tigum river. These shales belong to the same horizon as those
in the Bondoc Peninsula, known as the Vigo series, and are Lower Miocene
or Oligocene. This shale yields small amounts of natural gas, which
may or may not have any relation to small coal seams.

Apparently there are three principal shale horizons; lowermost, the
Eocene, which is associated with sandstones and coal seams; next, the
Oligocene or Lower Miocene, in which the oil seeps are found; and upper-
most, the Miocene with more coal seams.

1 Occurrence of Petroleum in the Philippines. Econ. Geol. (1918) 11, 247.

WARREN DUPRlD SMITH

I
5

-g

a"S

iii

s -as

Hi ill

^ 'a 5

|aa

! <

3 a

52 PETROLEUM IN THE PHILIPPINES

The typical oil (Vigo) shale on Bondoc Peninsula may be described
as (quoting from report of Pratt and Smith, p. 331) "consisting of fine-
grained shale and sandy shale interstratified in thin regular beds from
5 to 10 cm. in thickness. Occasional beds of sandstone occur varying
from 10 cm. to 1 m. in thickness. The fine-grained shale is gray, blue, or
black and is made up almost entirely of clay. The blue or black fine-
grained shale in the Vigo formation usually emits a slight odor of light
oils upon fresh fracture and in some outcrops is highly petroliferous.
The material loses this odor and assumes a light-gray color after it has
been exposed to the air and becomes thoroughly dry." These shales
contain numerous f oraminifera of the genus Globigerina, which may be
the source of the oil. Although present numerously, these organisms
did not appear to comprise any large percentage of the volume of these
shales.

On the island of Cebu there is a similar shale series, dark blue in color
and fine-grained, in which the oil seeps are found.

Another important feature of the Philippine Tertiary is the presence
of several limestone horizons in striking contrast to the American west
coast Tertiary. These limestones, in places, attain thicknesses of
several hundred feet.

In general, we may say that the Philippine Islands consist of a series
of anticlinal regions, which are marked by the island masses, and syn-
clines, which are occupied by the narrow straits between the islands.
The principal folding has been east and west, with minor flexures north
and south. The anticlines are generally sharp, as is the case in Sumatra,
Java, Burma, and other parts of the Far East. In South Sumatra, Tob-
ler has shown that the anticlines are only 2000 ft. across the crest and that
wells must be located on the crest in every case. In Tayabas, the struc-
ture can easily be understood by a study of the map accompanying the
paper by Pratt and the writer. This shows that the anticlines are
generally sharp and the dips are quite steep. The Maglihi anticline
on Bondoc Peninsula is a typical example and less than J^ mi. wide. The
axis of the principal structures coincides with the general direction of the
principal tectonic lines of the archipelago; i.e., north and south with
minor departures from this. Accompanying this folding there has been
more or less faulting. Just how great the throws are, not enough de-
tailed work has been done to determine. There is enough evidence to
indicate a considerable amount of faulting throughout the archipelago.

On Cebu, Pratt has shown that the seeps near Alegria are located at
the crest of a very sharp anticline. The well near Toledo, which shows
some oil, is apparently on a monocline in which the beds dip 50 to 60
to the northwest.

In Leyte, the petroleum seeps are along the outcrops of steeply dip-
ping strata (Vigo shale series).

WARREN DUPRE SMITH

On Panay, the shale
beds yielding natural gas
are generally monoclinal,
but there is one well-defined
anticline, known as the
Maasin anticline, which
might be a favorable lo-
cation for a test well.

In Tayabas and Cebu,
there is a sandstone mem-
ber, to which the local
name "Canguinsa sand-
stone " has been given,
which lies unconformably
upon and overlapping the
great shale series. In
some cases, as in Leyte,
residual bitumens are
found in this formation.

Very probably, trans-
portation will depend on
inter-island boats as most
of the 750 mi. of railroad in
the archipelago does not
tap the petroleum localities.
In the transportation of
machinery and the location
of docks, great care will
have to be exercised
because of typhoons.

Labor is plentiful but
unskilled. However, the
Filipinos show a great
aptitude along mechanical
lines and, under competent
white foremen, make very
excellent workmen. The
prices for labor vary with
the different tribes and
localities. Present prices
are commensurate with
those in other parts of the
world. The Filipino's
fondness for holidays ne-

J2o
0%

'v'>

"tf

O .-i

-s s -

o
^

Ills

I 1

*= p.

54 PETROLEUM IN THE PHILIPPINES

cessitates a larger pay-roll than is usually warranted by the size of the job.
The manager will have to take this into account.

Philippine petroleum has a paraffine base and is usually reddish to
violet in color. It is quite clear, and closely resembles oil from Burma
and Sumatra. Table 3 gives a fairly complete analysis made by Rich-
mond, former chemist of the Bureau of Science, and others. Table 4
contains an analysis of the petroleum residue from the Island of Leyte.
The paraffine content of the Philippine petroleum is very high; a beer
bottle full of oil from the Toledo well in 1908, which the writer col-
lected and put imperfectly sealed into his saddle bags, on unpacking three
days later, contained no oil but was half full of solid paraffine.

The residual bitumens from Villaba, Leyte, are found in lenses and
pockets in the Canquinsa sandstone. These have been fully investi-
gated by Pratt. Physically they more nearly correspond to ozocerite
than to any other of the natural bitumens.

TABLE 4. Physical Properties of Natural Bitumens from Villaba, Leyte

OUTCBOP OUTCROP

PROPERTY A AND B PROPERTY A AND B

Specific gravity. . . 1 . 05 Luster Brilliant

Hardness 2. 00 Structure Columnar

Color Jet black Fracture Conchoidal

Streak Black Flows Intumesces, softens,

and flows imperfectly
at 150 C.

The writer agrees with Pratt in the belief that there is a small com-
mercial supply of oil in the Philippines, very much as in Formosa. He
seriously doubts, however, that petroleum exists in large enough quantities
to attract large capital from America, considering the distance and the
many unfavorable conditions to be encountered. The size, steepness
of dip, and broken nature of many of the structures are not favorable
to large production.

All the oil which the writer has seen in the Islands is in the shallow wells
mentioned and in seeps in shales, and these seeps have been small. He
has seen no oil in beds either below or above these shales. In the petro-
liferous shales are a number of forminifera with Globigerina predomi-
nating. It may be that all the oil has come from the decomposition of
these organisms.

DISCUSSION

WALLACE E. PBATT,* Houston, Tex. (written discussion). Doctor
Smith's correction of my statement in Economic Geology that the Philip-
pine Oligocene rests directly upon a pre-Tertiary basement of crystalline

* Chief Geologist, Humble Oil & Refining Co.

DISCUSSION 55

rocks is well taken. I concede that some of the older indurated shales
and limestones may properly be classed as Eocene. My statement
should have been limited to the petroleum-bearing areas that I described
and in which it applies by reason of the absence of the older rocks.

In this connection, I may record my impression that the typical
Philippine section is not as thick as the 15,000-ft. (4572 m.) section ex-
posed on the eastern flank of the cordillera of the Island of Panay and
mentioned by Doctor Smith. I think the average thickness for the
Philippine sedimentary column would be about one-third of the figure
quoted. The Panay section is unusual in another respect; at its base
there are thousands of feet of unfossiliferous conglomerates and coarse
sands which appear to be of extreme shallow-water origin, whereas in the
typical column this basal member is not more than 200 ft. (61 m.) thick.

A recent press dispatch states that Cebu, the second largest port in
the Philippine Islands, and a city of about 100,000 population, is now
paving its streets with rock asphalt secured from a quarry in the vicinity
of the town of Villaba, on the neighboring island of Leyte. I believe this
work marks the first commercial use of the petroliferous deposits of the
Philippines. The circumstance is interesting not only as a first step
in making this natural resource serve industry, but as an evidence of the
extent of the residual deposits that constitute the surface indications of
petroleum in one of the possible oil fields in the Philippines.

As a matter of fact, not only is the stratigraphic column in the Philip-
pines dominantly shale with interbedded sandstone as described by
Doctor Smith of suitable character and adequate thickness to yield
commercial petroleum, but the surface evidences of the existence of
petroleum on some of the islands are quite remarkable. These various
seepages and asphalt deposits are described briefly in my paper in Eco-
nomic Geology to which Doctor Smith refers. 2

The situation in the Philippines, in so far as the geologic conditions
are concerned, is certainly one that would lead many of the geolo-
gists engaged in the present fervid search for new petroleum fields
to recommend drilling exploration on some of the islands, provided
their clients commanded adequate capital. The possibilities in the
Philippines are the more impressive when one reflects that in Borneo,
Sumatra, and Java, as well as in Formosa and Japan, commercial produc-
tion of a petroleum similar in character to that which comes to the surface
at places in the Philippines is obtained from beds of the same geologic
age and composition as those in the Philippines.

2 More detailed descriptions with maps and geologic sections will be found in
the following references: Wallace E. Pratt and Warren D. Smith: Geology and
Petroleum Resources of the Southern Part of Bondoc Peninsula, Tayabas Province,
Philippines. Phil. Jnl Sci., Bur. Sci., Manila (1913) Sec. A, 5, 301-376; Wallace E.
Pratt; Occurrence of Petroleum in Cebu, Id&m. (1915) Sec. A, 4; Wallace E. Pratt:
Petroleum and Residual Hydrocarbons in Leyte, Idem. (1915) Sec. A, 4,

56 PETROLEUM IN THE PHILIPPINES

Under different conditions, a prospect like that in the Philippines
would evoke an active drilling campaign. I have had opportunity to
make direct comparison in the field between conditions in parts of Cen-
tral America, for instance, and in the Philippines and I can conceive no
possible contention but that the geologic conditions in the Philippines
are decidedly the more promising. Yet these same regions in Central
America have interested dozens of large petroleum corporations; con-
cessions there have been sought eagerly for years and are at present,
indeed, being exploited.

I am convinced that adequate exploration of the petroleum deposits
in the Philippines has been prevented, not by unfavorable geologic con-
ditions but by prohibitive regulations of the local mining laws. Practi-
cally all the possibly petroleum-bearing territory in the Philippines is
government land. It can be acquired only under laws similar to the
mining laws of the United States. Petroleum lands are subject to
"location" as placer-mining claims. An individual may obtain a single
claim of 8 hectares (20 acres) in any one field while a corporation compris-
ing eight individuals can secure only one claim of 64 hectares (160 acres)
in any one field. Except by a direct evasion of the law, therefore, it is
impossible to control the acreage requisite for large operation, such as
must be contemplated by any enterprise that looks as far afield as the
Philippine Islands.

It is unlikely that successful exploration will result from the efforts of
the Government owned corporation, the formation of which is recorded
in the legislation quoted by Doctor Smith. This corporation, like any
other, is subject to the laws that prevent the acquisition of suitably large
holdings and its capitalization of 500,000 pesos ($250,000) is not adequate.
If the Filipinos were to grant concessions of hundreds of thousands of
acres, as some of the Central and South American republics have done,
I believe their possible petroleum resources would be promptly and thor-
oughly tested by the drill.

DAVID WHITE,* Washington, D. C. This paper is very timely since
the Philippine Islands are presumably open to the enterprise of the Amer-
ican driller, whereas much of the territory in that part of the world is
closed to us.

The United States has ambitious plans for the operation of a great
merchant marine, which is to be oil burning in the main, and it takes but
a glance at the world map to see the strategic advantage of oil supplies in
the Philippines for such marine operations. It is a little difficult to
understand why more attention has not been given to the Philippines, in
spite of the difficulties attending development in these islands.

* Chief Geologist, U. S. Geol. Survey.

DISCUSSION 57

A number of American oil companies are, I believe, at the present
moment taking an interest in the possibilities of the Philippines. Im-
portant factors in the formulation of opinion regarding the importance
of the oil deposits of the Philippines, as brought out by Mr. Pratt, are
the point of view and the breadth of experience of the examining geologist.
The average oil geologist, whose experience has been mainly in the
Appalachian region, the Mid-Continent, or Louisiana, or possibly even in
California, on seeing the narrowness of the basins, the closeness of the
folding, and the presence of igneous rocks here and there, would be likely
to draw unfavorable conclusions as to the possibilities of the Philippine
Islands. Geologists visiting that region should be familiar with the
geological conditions of oil occurrence in Japan, Formosa, the East
Indies, or in the Baku district, and their conclusions should be formulated
with the knowledge and understanding of the occurrence of oil in those
regions rather than in the United States.

58 PETROLEUM INDUSTRY OF TRINIDAD

Petroleum Industry of Trinidad

BY GEORGE A. MACREADY, Los ANGELES, CALIF.

(St. Louis Meeting, September, 1920)

TRINIDAD, British West Indies, is an island near the north coast of
South America, situated between latitudes 10 and 11 N., and opposite
the numerous outlets of the Orinoco River Delta. It is separated from
Venezuela by the Gulf of Paria (salt water) and straits over 5 mi. (8
km.) wide. The area of the island is approximately 1750 sq. mi. (453,-
250 hectares) and the population is approximately 400,000. The climate
is tropical with an annual rainfall of from 45 to 60 in. (114 to 152 cm.).
The oil fields consist of several units, or fields, located in the southern
half of the island. Approximately 90 per cent, of the total production
has been yielded by fields situated within 7 mi. (11.3 km.) of the famous
asphalt lake and on the southwest peninsula.

The most important producing fields, or units, are the following,
which are shown on the accompanying map:

Brighton, or Pitch Lake Field, operated by the Trinidad Lake Pe-
troleum Co., Ltd., is situated beside the famous Pitch Lake; it even en-
croaches on the lake.

Vessigny Field, operated by the Trinidad Lake Petroleum Co., Ltd.,
is situated 2 mi. (3.2 km.) south of Pitch Lake.

Lot One Field, operated by the Petroleum Development Co., Ltd.,
the United British Oilfields of Trinidad, Ltd., and Stollmeyer, Ltd.,
is situated 3 mi. south of Pitch Lake upon Lot One of Morne PEnfer
Forest Reserve and adjoining properties.

Parry Lands Field, operated by the United British Oilfields of Trini-
dad, Ltd., and the Petroleum Development Co., Ltd., is situated 3J^
mi. south of Pitch Lake on Lot Three of Morne 1'Enfer Forest Reserve
and adjoining properties.

Point Fortin Field, operated by the United British Oilfields of Trini-
dad, Ltd., is situated at Point Fortin, 6 mi. southwest of Pitch Lake.

Fyzabad Field, operated by Trinidad Leaseholds, Ltd., is situated
several miles southwest of Fyzabad Village and 6 mi. south-southeast of
Pitch Lake.

Barracpore Field, operated by Trinidad Leaseholds, Ltd., is situated
several miles south of San Fernando and 15 mi. (24.14 km.) east of Pitch
Lake.

GEORGE A. MACREADY

Tabaquite Field, operated by Trinidad Central Oilfields, Ltd., is
situated 4 mi. southeast of Tabaquite Railroad Station, and 30 mi.
(48.28 km.) northeast of Pitch Lake.

N- V 3 O O

z> f js /r y T E y s is as a
| sp I?

5 o * 0*^ -^ 8 E

5 . gttiijj*

5iI*l-F I
M l I* ll 1

lllllll

3 %
S o^

J fts W)

III

111

Guayaguayare Field, operated by Trinidad Leaseholds, Ltd., is situ-
ated in the extreme southeast corner of the island 45 mi. (72.42 km.)
from Pitch Lake.

From 1870 to 1900, several attempts were made to obtain oil on Trini-

60 PETROLEUM INDUSTRY OF TRINIDAD

dad but although small quantities of oil were encountered, no com-
mercial production resulted, and most of the wells were abandoned.
An attempt was also made to obtain oil from the crude lake asphalt,
probably by a cracking process, but without commercial success.

The present industry can be said to commence with wells drilled since
1900 near Guayaguayare, in the extreme southeast corner of the Island.
Several years later wells were drilled near Point Fortin, southwest of
Pitch Lake, which yielded commercial quantities of oil but not sufficient
for export.

In 1908, the New Trinidad Lake Asphalt Co., Ltd., commenced drill-
ing at the Pitch Lake and encountered an excellent flow of oil in its second
well. Other wells were drilled and, in 1910, this company exported the
first steamship cargo of oil from Trinidad. Since then, the quantity of
oil produced and the number of companies exporting has increased. The
production in 1908 was 169 bbl., in 1912, 436,805 bbl.; and in 1917,
1,599,455 bbl.

GEOLOGY
Stratigraphy

All petroleum produced by Trinidad has been yielded by strata of
Tertiary age. In general, the Tertiary strata consist of clays, shales,
marls, and sandstones; conglomerate is extremely rare and limestone is
uncommon. The sandstone is usually composed of small quartz grains
uniformly sorted. Cretaceous and metamorphic rocks underlie the
Tertiary. The most important portion of the Tertiary strata consists
of sandstone and shale, which grades upward into marl and shale con-
taining marine organic material and evidences of petroleum. The organic
material in this shale is probably the primary, or "mother," source
from which Trinidad petroleum is derived. The upper portion of the
shale contains sandy strata into which petroleum has migrated and ac-
cumulated in quantities sufficient for commercial exploitation. Eocene
fossils occur in the lower part, but the upper part may extend into the
Oligocene. This includes the Naparima clay, Cruse oil zone, and Stoll-
meyer oil zone.

The Morne PEnfer formation unconformably overlies the above-
mentioned, and consists of sandstone and clay shale in approximately
equal proportions. The lower sandstones are often heavily impregnated
with asphalt and often outcrop as " pitch sand" cliffs. The author
believes that this asphalt has migrated from the underlying shales and
marls. Near Pitch Lake, some oil may be produced from this formation.
Strata younger than the Morne TEnfer have not yielded commercial
quantities of oil and are unimportant.

The accompanying tabulation describes the geological formations of

GEORGE A. MACREADY 61

Trinidad in more detail. The areal distribution of the formations is
shown approximately on the map.

Structure

The areal geology of the island is separated into two parts by the
great east- west fault passing near Port of Spain and Matura, and ex-
tending from the Atlantic Ocean into Venezuela. North of the fault is
the area of Metamorphics, forming the Northern Mountain Range.
South of the fault is a great undulating blanket of Tertiary strata.

The dominating features of the Tertiary structure are: A synclinal
or monoclinal trough between the Central and Northern Mountain
Ranges; an anticlinal uplift along the south side of the Central Range
striking east-northeast by west-southwest, from Pointe a Pierre to Nariva
Swamp ; an undulating synclinal structure between San Fernando, May-
oro Point, Guayaguayare Bay, and Icacos Point with an east-west strike;
the magnitude of erosion at the unconformity below the Morne 1'Enfer
formation. Numerous local folds, faults, kinks, anticlines, and synclines
modify the broader features and are very important in the concentration
of petroleum.

Occurrence oj Petroleum

All the producing oil fields of Trinidad (except Tabaquite Field) are
within or on the flanks of the great synclinal trough or basin of the
southern part of Trinidad. Most of them are on the southwest penin-
sula. This undulating synclinal structure is underlain by Naparima
clays, marls, and organic shales. It forms the drainage area from which
petroleum has accumulated. This petroleum has concentrated in com-
mercial quantities near anticlinal folds.

The location and richness of each productive area are modified by
the magnitude and condition of the unconformity below the Morne
TEnfer formation: by the channels of migration: by the local conditions
of porosity of reservoir sands; by the lenticular condition of the oil
sands; by the facility with which connate salt waters were displaced by
oil. There are three principal horizons in which petroleum usually,
but not always, is concentrated in commercial quantities.

The Cruse oil zone is persistent because its proximity to the organic
shales permits ready saturation, has permitted much time for connate
waters to be forced out, and Tertiary erosion has not attacked it as
frequently as higher strata. Its thinness and high gas pressure increase
operating cost. This condition applies at Parry Lands, Morne 1'Enfer
Forest Reserve, and Point Fortin.

The Stollmeyer oil zone overlies the organic shales and the sands are
lenticular. The porosity and saturation of the oil sand varies locally.

62 PETROLEUM INDUSTRY OF TRINIDAD

It may or may not, locally, be conformable below the Morne PEnfer
formation or it may be entirely missing. Where apparently conformable
below the Morne PEnfer formation, conditions are simple and anticlinal
structures may prove very rich, as in the Morne PEnfer Forest Reserve.
As the unconformity increases, modifications occur. Part of the Stoll-
meyer sand may have been removed by erosion and the remainder sealed
by the clayey base of the Morne PEnfer formation. One flank of an
anticline may prove richer due to better drainage area on that side, as
may be the case at Lot One. A flank of the anticline may be enriched but
the apex barren because the sand is missing; such may be the case at
Point Fortin, Barracpore, and possibly at Brighton. Connate salt water
has not been completely forced out of all the sand lenses but usually
remains only in the lowest lenses.

The Morne PEnfer formation is enriched by oil migrating from the
underlying organic shales. Where the organic shales lie close below as a
result of Tertiary erosion and the Morne PEnfer sands are not too thick
or too clayey at the base, saturation may be sufficient for commercial
production; such may be the condition in fields near Pitch Lake. Where
the sand is too thick and petroleum has migrated slowly, saturation may
not be sufficient for commercial production; such may be the condition
of pitch sands in the Forest Reserve.

Near Tabaquite, petroleum has concentrated in sands closely associ-
ated with organic shales but too distant from other fields for correlation.

TECHNOLOGY
Drilling

The rotary system of drilling has proved most successful in the produc-
tive fields. Cable tools are usually confined to some, but not all, isolated
test wells, to special work, and to repairing damaged wells; but in the
early days many wells were drilled and finished with them. Portable
drilling machines have been successful for shallow wells in the central
and extreme southern portions of Trinidad. Some wells have been
drilled with Canadian and Galacian outfits.

Some difficulty is encountered in penetrating pitch strata. If sandy,
they are hard and wear off rotary bits. If clayey, they are plastic and
squeeze slowly but persistently into the hole and grip the drill pipe above
the bit; this has been overcome by using hot water circulation and driving
casing through the pitch.

For wells expected to be over 1000 ft. (305 m.) deep, it is common
practice to drill with rotary and set 15^ in- 70-lb., 13-in. 54-lb., or 12^-
in. 50-lb. screw casing as the outside string. Either this or the succeeding
one is used to shut off water preferably, but not always, by cementing.
Wells are usually drilled into the oil sand using 6-in. (15.24-cm.) or 8-in.

GEORGE A. MACREADY 63

perforated drill pipe equipped with a blow-out preventer on an outer
string. With all in readiness to receive a big flow of oil, drilling proceeds
until the oil sand is drilled through or the flow of oil and gas prevents far-
ther progress. Then the drill pipe is left as it is and the wash pipe
recovered when convenient. In shallow fields, a common practice is to
set about 100 ft. (30.5 m.) of 12^-in. (31.75-cm.) casing as a conductor
and then to drill through the oil zone. Perforated casing is substituted
for drill pipe and the well tubed to pump or flow as the case may be.

Casing is not perforated in the well if it can be avoided; the usual
practice is to set shop perforated casing. Screen casing has not been
successful because of clogging with clay. Explosives are never used to
increase production and rarely to break up junk.

For a well 1500 ft. (457.2 m.) deep, 60 days is a fair average time from
first actual drilling until production begins. This includes usual delays,
casing setting, changing crews, waiting, etc. The actual number of
days in which hole is dug may be as low as fourteen. In 1918, $15,000
was a fair average cost to the depth of 1500 feet.

Production

Wells in the thin deep sands usually begin production with a large
initial flow or gust under great gas pressure, yielding up to 100,000 bbl.
in the first few days and later choking with sand or shale. During the
first year, the production is dependent largely on spasmodic flows aided
by bailing or tubing agitation, but after the first year few wells yield
over 100 bbl. daily. The shallower wells with thicker oil sands begin
production sometimes as pumpers and sometimes by flowing. The
initial flow averages much less than for the deeper wells, but is less
spasmodic and less costly to control. Few wells flow for over a year.

After wells cease flowing they are usually pumped by the walking
beam. Sand and mud must be cleaned out frequently for two years or
more. None of the southwest fields have been successful in
pumping from a central power or jack. Few wells have produced over
eight years and many cease producing in the second or third year. The
production of individual wells is greatly influenced by the local porosity
of the oil sand and the size of individual oil-sand lenses.

Character oj Petroleum

Trinidad petroleum varies greatly in specific gravity, not only in
different fields, but also within the same field. It is (with one exception)
of asphaltic base. Oil from the Trinidad Central Oil Fields, Ltd., near
Tabaquite has little asphalt but some paraffine, and yields much gaso-
line and kerosene by distillation. The average specific gravities for

PETROLEUM INDUSTRY OF TRINIDAD

Geologic Column of Trinidad

Name

Thick-

Lithology

Age

of
p__

ness.

Petroleum Evidence

Miscellaneous Remarks

r or*
mation

Feet

Folding

Principally soft clay, silt, vegetable

Consists of stream alluvium and

remains Less sand. Rarely con-

swamp deposits.

gloineritic.

Asphalt cnnes and seepages and mud

volcanoes occur by breaking through

from underlying formations.

Never tilted.

Unconformity

100

Ferruginous sands, clays and con-

The Llanos formation consists of ma-

glomerates.

terial deposited in the basin of which

Evidences of asphalt occur by break-

the present Orinoco Valley was a

ing through from underlying for-

portion Large areas occur in Vene-

mations
Usually nearly flat; rarely tilted to 5

zuela, particularly in the Llanos, or
plains, of the Orinoco River Valley,
but in Trinidad where the formation

appears thinner, erosion has dissected

it until only hill-top remnants and a

*-*

few larger areas remain.

When seen from the Gulf of Paria, the

topography of southern Trinidad has

the appearance of a former flat

is'

surface, such as a sea bottom, up-

lifted to a plateau 100 to 300 ft.

P^i

above sea level through which

"islands" or peaks of older resistant

rocks project. (Erin Peak, Morne
1'Enfer. Soldado Rock, Naparima

Hill for example.) The present

drainage system has dissected this

plateau into a low, but steep topo-

graphy gentler than canyon topo-

graphy.

Unconformity

400

Porcellanite, lignitic clay, lignite, i Usually occurs within synclines flanked
partly altered wood, shale, clay, and by the 1'Enfer formation. It may
sandstone^ exhibiting great lateral be of fresh-water origin of material

variation in character. Conglomer- j derived from the older tertiary

atee not known. rocks. In troughs, or synclines, de-
Rarely contains asphalt and has no position may have been uninterrupted
commercial oil horizons. between this and the Llanos forma-

Usually found tilted but rarely over

tion.

35.

This formation corresponds to the

P-I

upper tertiary strata in reports of

E. H. Cunningham-Craig.

Porcellanite has not been proved to

exist in other formation in Trinidad.

Unconformity (locally)

2500

Sandstones of uniform small quartz

The following thicknesses have been

grains separated by bands of clay

measured: 2500 ft. at Erin Bay,

shale and rarely by lignite.

1200 ft. at Guapo Bay, 900 ft. at

No conglomerate known. Vessigny Bay, 800 ft. at Morne

The lowest sands are commonly

1'Enfer.

saturated with asphalt. Near Morne

Fossils of doubtful Oligocene age have

1'Enfer 300 ft. of "tar sand" has

been found near this formation. In

Px>

been observed in the lowest 700 ft.,
some of which was very rich.

the Central Range mountains, Mio-
cene fossils occur in what may be the

l?o

Some of the oil fields nearest the Pitch

equivalent formation Because of

Lake may derive production from

the great unconformity below this

sands of this formation.

formation, the author prefers to

Tilting is commonly over 20 but
rarely as much as 90.

regard it as Miocene.
The name of this formation is selected

because of its occurrence in the

Morne 1'Enfer Forest Reserve.

>> 600

Blue and gray clay often very sticky.

This forms the impervious cover over

the Stollmeyer oil zone.
The author is convinced that there is a

O 43

great unconformity below the Morne

O-j? ^

1'Enfer formation, but owing to the

clayey non-resistant nature of the

VOL. LXV. 5

GEORGE A. MACBEADY

Age

Name
of
For-
mation

Thick-
ness
Feet

Lithology
Petroleum Evidence
Folding

Miscellaneous Remarks

Eocene or Oligocene

strata the exact horizon is difficult
to identify. It probably occurs in
these clays, below the lowest Morne
1'Enfer sand.
This condition was observed by the
author on a much smaller scale at a
small island which rose overnight
from the sea near Trinidad in 1911.
A few weeks later waves had eroded
it completely and deposited tne
material on similar adjacent clayey
material.

Unconformity

1 Eocene or Oligo"
cene

Stollmeyer Oil
Zone

500

Overlapping pancake-shaped lenses of
sand and shale alternating.
The sands contain oil and salt water,
the best saturation of oil being in the
upper part of tne zone and not far
from an anticlinal axis.
Salt water is usually confined to the
lower lenses, but has been found at
the top of the zone.

This is the most profitable oil forma-
tion on Trinidad.
It is difficult to correlate individual
lenses from well o well but the group
or zone can easily be traced through a
field.

Eocene or
Oligocene

COQ

600

Principally clay shales with occasional
lenses of sand. Foraminifera occur
in the lower part of these shales.
Some of the sand lenses are highly
saturated with petroleum and gas
under great pressure.
Lenses occasionally contain salt water.

Several oil wells yield production from
restricted sand lenses in this forma-
tion.

Cruse Oil Zone

Sand.
Often saturated with petroleum and
gas under great pressure.
Salt water may occur.

> - . ,. - - - '

This is the most persistent oil horizon
on Trinidad, but its thinness, depth,
and violent gas pressure increases the
cost of exploitation. It is identified
over a large area in the northern
portion of the Morne J'Enfer Forest
Reserve where it occurs 1000 to 1200
ft. below the top of the Stollmeyer oil
zone. Many of the gas-mud vol-
canoes of Trinidad may occur near
the outcrops of this horizon.

S0>
g

Naparima Clay

4000

Clay, shale, and marl containing
marine organic matter.
Outcrops often with a perceptible
odor of kerosene and where an
irridescent film of oil covers pools
of water. Manjak veins occur near
San Fernando.
Commonly tilted to vertical with
abrupt changes and overturns.

Large areas outcrop near San Fer-
nando. Folding is so complex and
abrupt that it is difficult to obtain a
reliable measurement of thickness.
This formation may be the "mother
rock" from which the petroleum of
Trinidad is derived.
Some of the light oil from Trinidad
may come from wells in this forma-
tion.

Clay and shale and hard gritty sand-
stone.

Eocene fossils occur in or below the
Naparima clay. The author has not
made extensive studies of the
Tertiary strata below the Naparima
clay.

Unconformity

Creta-
ceous

Dark , black or brown shale and lime-
stone.

Cretaceous strata have been reported
in limited areas in the Central Range
of Trinidad and doubtfully farther
south. Large mountainous areas
of Cretaceous occur in Venezuela.

Unconformity

Pre-Creta-

ceous

Metamor-
phics

Schist, gniess (Pre-Cretaceous vol-
canics near Toco).

The Northern Range of Trinidad con-
sists of a metamorphosed complex
bounded on the south by an east-
west fault passing near Port of Spain
and Natura Bay, and extending into
the Atlantic Ocean and Venezuela.

66 PETROLEUM INDUSTRY OF TRINIDAD

different fields are: 0.9524, 0.9722, 0.9589, 0.9459, 0.9333, 0.9211, and
0.809 4 2; or, 17, 14, 16, 18, 20, 22, and 43 BaumeV

Transportation and Utilization

The Trinidad Lake Petroleum Co., Ltd., and the Petroleum Develop-
ment Co., Ltd., together operate a 6-mi. (9.66 km.) pipe line from the
Morne PEnfer Forest Reserve to a tank farm at Brighton near Pitch
Lake beginning as 4 in. (10.16 cm.) and increasing to 10 in. (25.4 cm.).
At Brighton pier are facilities for docking -and loading steamers up to 35,-
000 bbl. in 24 hr. Much of this oil has been exported to the United
States for industries using asphalt and its products.

The Trinidad Leaseholds, Ltd., operates approximately 28 mi. (45
km.) of 6-in. (15.24 cm.) pipe line from the Morne PEnfer Forest Reserve
to Pointe a Pierre, with a short side branch from Barracpore. At Pointe
a Pierre is a tank farm and pipe trestles to a loading station 1 mi. (1.6
km.) from shore where full-size tank steamers can be loaded. Most of
this oil has been taken by the British Admiralty, although considerable
has been disposed of as bunker fuel to steamships and some has been
refined at Pointe a Pierre.

The United British Oilfields of Trinidad, Ltd., operates a 6-in. (15.24
cm.) pipe line 6 mi. (9.66 km.) in length from the Morne PEnfer Forest
Reserve to Point Fortin, with an additional branch contemplated. At
Point Fortin, oil is loaded in barges and towed to tankers anchored in
the Gulf of Paria. Loading a tanker requires several days. A refinery
at Point Fortin produces " navy fuel." Most of this oil has been taken by
the British Admiralty, but some of it has been disposed of as bunker fuel
oil to steamships and some early shipments went to various places.

The Trinidad Central Oilfields, Ltd., operates a 3-in. (7.62 cm.)
pipe line from the Tabaquite oil field to a loading pier at Claxtons Bay.
This oil is very high in gasoline and is nearly all refined for petrol, kero-
sene, and fuel residue.

Stollmeyer, Ltd., operates a 2-in. pipe line 2 mi. (3.22 km.) in length
from near the Morne PEnfer Forest Reserve to Guapo Bay where sail
lighters can be loaded.

FUTURE POSSIBILITIES

The future of the petroleum industry of Trinidad depends on the
discovery of new oil fields or units as much as on complete exploitation
of the known fields. The most obvious oil fields are already in exploi-
tation. The writer is confident that a thorough search will result in
the discovery of other oil fields which will compare favorably with the
known fields.

DISCUSSION 67

The discovery of new oil fields necessitates the drilling of isolated test
wells of which most will be barren. Exploratory drilling should be guided
by a thorough geological study of a broad area with special attention to :
The magnitude and trend of the unconformity below the Morne PEnfer
formation, character of strata below this unconformity, and geologic
folding. Such geological study will reduce the number of barren wells,
which is the greatest expense of exploration. In the known fields a
continuous drilling program will be necessary to maintain the production
with declining wells.

DISCUSSION

RALPH ARNOLD, Los Angeles, Calif. The Trinidad field has been the
graveyard of the reputation of many drillers and production men. Ap-
parently the effort to hold back this clay and sand by the use of strainers
is unsuccessful because the well will gradually plug up to such a point that
every known method will fail to loosen the pores and allow the oil to come
in. As wells put down near old producers will show large initial produc-
tion, the ultimate yield of oil will be increased by putting down secondary
wells.

In one field, a perfect dome, the sand is in lenticular form. At first
the wells showed considerable water but now the oil pumped is free
from water.

E. DEGOLYER, New York, N. Y. I have understood that the chief
difficulty in Trinidad operations was to find any strainer that would hold
back the sand, which is of uniformly fine grain. The ordinary sand is
composed of grains of assorted sizes. The strainer lets the fine sand pass
through and holds a sponge of the larger grains outside so that after a well
starts producing, this coat of larger grains on the outside does as much
straining as the strainer itself.

R. VAN A. MILLS, Washington, D. C. It seems probable that several
factors enter into the sanding up of wells. Underground changes in the
gravities and viscosities of the oils incident to the operation of wells may
play a part in this trouble. In California there are instances of the
Baume* gravities of oils issuing from wells in new fields undergoing reduc-
tions of 7 in the first months of production. Under these conditions the
deposition of residual matter from the oils would influence the sanding
up of the wells.

A more important point is the deposition of inorganic matter (mineral
salts) together with silt in the sands. This induced effect is accomplished
through the agency of the waters accompanying the oils concentration
and chemical reactions being responsible for the deposition of the salts.

Water interferes with the movements of the oils to the wells espe-
cially where the oils are of high viscosity. The shutting off of the oils

68 PETROLEUM INDUSTRY OF TRINIDAD

through the agency of waters is probably the worst of these underground
troubles with which we have to deal. I believe that by reducing the
rapid flows of oil and gas we can largely eliminate these troubles.

R. A. CONKLING,* St. Louis, Mo. Mr. Macready has not made any
mention of the Tabagie field, which has a very light oil, 35 to 40, that
comes from Cretaceous and other sands much higher in the Tertiary.

RALPH ARNOLD. In the principal producing area, there is enormous
production during the first three or four days and very light production
thereafter. Many of the wells have given as high as 15,000 to 20,000
bbl. per 24 hr. for the first three or four days, and but a mediocre produc-
tion after that.

ARTHUR KNAPP, Shreveport, La. One other place where the same
thing occurs is Louisiana. The trouble is not sand but squeezing clay.
The clays in Trinidad are contaminated with oil and pass through the
perforated casing. It is useless to place a screen for the clay squeezes
through and appears in the overflow in the form of paper-thin sheets.

E. DEGOLYER. I have wondered if sanding-up is not often a case of
the pinching together of top and bottom clays rather than any blocking of
the well sand or something of that sort. These wells, when they come in
as gushers, produce large amounts of sand, so that if all the sand is blown
out, there is nothing to hold up the overlying clay or mud. There must
be some considerable tendency for them to close together and, where the
sand had been imperfectly exhausted, a small production would continue.

RALPH ARNOLD. We operated on that theory at one time and tried
to control the flow of the wells at the start, and by holding back the sand
allowed the production to be slower, but I think the records show that
the wells that ran wild at the start gave the greatest ultimate production.

* Head Geologist, Roxana Petroleum Co.

OIL-SHALES AND PETROLEUM PROSPECTS IN BRAZIL 69

Oil-shales and Petroleum Prospects in Brazil

BY HORACE E. WILLIAMS, A. M.,* Rio DB JANEIRO, BRAZIL

(St. Louis Meeting, September, 1920)

IN VIEW of the frequent occurrence of petroleum in other parts of the
world, it seems odd that so large an area as is contained within the
borders of Brazil should be without this product. This apparent de-
ficiency may be due, however, to our ignorance of the regions in which it
may exist. In some places, indications point to the probable existence
of petroleum in ages gone by; and while the presence of petroleum pools
may be problematic, in several regions conditions not unfavorable to
their occurrence exist.

Yet, Brazil has enormous oil resources in the rich oil-shales in dif-
ferent parts of the country. Many of these shales are very rich and
only suitable processes for the extraction of the oil are lacking. At the
present time, only a few small experimental plants are producing oil by
distillation from these shales. These plants have been the subject of
recent investigations by the Geological and Mineralogical Survey, a pre-
liminary report of which is in the hands of the printer. The only regions
where studies have not been made are the upper Amazon, the Acre, the
Rio Negro, and the Peruvian frontier, which really seems to be the
most promising field for explorations of any in the country.

In the vast plateau region of the interior north of the 20th parallel of
latitude, granites, gneiss, mica schists, and very old metamorphosed
sedimentaries predominate. Later, sedimentaries occupy a minor posi-
tion and, where found in the interior, represent a thin veneering resting
on the older rocks. At several places near the coast they have a greater
development and contain considerable beds of oil-shale and may, in
some cases, offer conditions favorable for the occurrence of oil. Such
deposits are found in the Permian rocks of central and southern Maran-
hao; in the Tertiary and Cretaceous beds along the coast of Alagdas
Sergipe, Bahia, and perhaps farther south in Espirito Santo; and in the
Parahyba embayment north of Cape Frio and in the interior Tertiary
basin of eastern Sao Paulo.

* Geologist, Brazilian Geological and Mineralogical Survey. '

70 OIL-SHALES AND PETROLEUM PROSPECTS IN BRAZIL

MARANHAO

The information at hand as to the detailed structure and distribution
of the rock formations of this state is very meager. It is derived princi-
pally from the paper by Dr. Miguel Arrojado R. Lisboa 1 on the Permian
rocks of Maranhao and from unpublished notes on these rocks in Piauhy
and Maranhao by Dr. Gonzaga de Campos, Director of the Brazilian
Geological Survey. The Permian beds are exposed along the Rio Para-
hyba for over 1000 km. and, generally, over the southern and eastern
half of the state. These beds are covered largely by the thinner Trias and
Cretaceous formations. In the extreme northwestern part of the state,
granite appears near the coast. While the Permian rocks have suffered
considerable folding in a minor way, the material in hand seems to indi-
cate a general synclinal structure across the state with the main axis
bearing northeast-southwest.

On the middle reaches of the Itapicuru and Mearim Rivers, bitu-
minous shales are found together with calcareous sandy and marly beds
associated with limestones. Occurrences are also met with near Cod6
on the Itapicuru, on the Rio do Inferno, at Fazenda da Uniao on the
Igarape Sant'Anna, on the Codosinho, and on the Rio Mearim at the
city of Barra da Corda.

At the occurrence on Rio do Inferno, the beds strike east and west
with a dip of 30 south. The lowermost bed consists of a bog-head coal,
somewhat similar to the Marahii beds of Bahia, overlying a thick bed of
well-laminated bituminous shales. In the bed of the Rio Mearim, the
bituminous shales are covered by a limestone with siliceous and
gypsiferous intercalations. These beds have a southerly dip and
are covered by over 50 m. of flaggy sandstones. At Grajahti,
farther southwest, the same gypsiferous limestone occurs but without the
bituminous shales, which, if present, are below the water level of the
river. The limestone dips northeast with the strike N. 60 W. It is
covered by a red conglomeratic sandstone. Similar beds are found in the
extreme southwest of the state and in northern Goyaz on the Rio
Tocantins.

The plains and lowlands of central Maranhao are so covered by the
lateritic formation that observations on the underlying rocks are difficult
especially as regards character and structure. Field work in this region
is practicably limited to the dry season, from May to November. Samples
of the oil-shale from this region gave the following results on analysis:
bitumen, 36.5 per cent. ; clays, 22.6 per cent. ; soluble carbonates, 40.8 per
cent.; and on slow distillation 450 1. (about 100 gal.) per ton. This ap-
pears to have been a very rich sample.

1 Permian Geology of Northern Brazil. Am. JriL. Sci. (1914) 37, 425.

HORACE E. WILLIAMS 71

Some prospecting work has been done in this region, a drill having been
mounted near Cod6, but it seems that the attempt was discontinued after
considerable depth was attained. Judging from the registered dips
and strikes observed by different parties, the region has suffered con-
siderable folding. For this reason special work should be done in
determining the structural and stratigraphic features before any extensive
drilling operations are undertaken.

ALAGOAS

Knowledge of this region is obtained chiefly from the paper by Dr.
John C. Branner 2 on the oil-shales of Alagoas. This has been supple-
mented somewhat by recent work on these shales by the Service
Geologico. 3 Shales rich in oil are found at several places along this coast.
The series of rocks to which the oil shales belong are found along the coast
about Cape S. Agostinho, Rio Formosa, Tamandare", Abreu da Una, etc.,
but at these places the unweathered shale does not appear. Farther
along the beach, in latitude 9 3', at Maragogy, the oil-bearing shales
appear at and a little above tide level. At this place they show a wrinkled
synclinal structure and outcrop frequently from this point south, as at
Sao Bento, Camax6, JaparatuM, and in front of Pitinguy, in latitude 9
7', where they are exposed at low tide. Dips are generally to landward.

At Barreira do Boqueirao, north of the Porto das Pedras, the shale
exposed has a thickness of 2 m., with a probable thickness of 3 or 4 m.in
all. At Camaragibe, the shales form a wave-cut terrace about 150 m.
wide; the dips observed were from 5 to 10. At this place several pits
were put down many years ago. Samples from these pits examined by
Boverton Redwood 4 showed the following composition:

PEE CENT. PEK CENT. PER CENT. PER CENT. PER CENT.

Volatile 30.6 24.8 27.1 25.5 7.8

Non-volatile combustible... 9.5 4.3 2.2 2.2 2.9

Ash 60.0 70.9 80.7 72.3 89.3

The shales are exposed at Barra do Santo Antonio and at Riacho Doce
in latitude 9 36'. The exposure at Riacho Doce is quite similar to those
already mentioned. Several pits were sunk and the shales were found
to be richer than those at Camaragibe. The composition was as follows:

Pi
Volatile

:R CENT.
34 9

PER CENT.
46 3

PER CENT.
26.9

PER CENT.
32.8

PERCENT.
25.4

Non-volatile combustible. .
Ash . . .

. 1.1
64

19.5
34 2

8.1
65

14.6
52.6

10.5
64.1

2 Oil-bearing Shales of the Coast of Brazil. Trans. (1900) 30, 537.

'Gonzaga de Campos: "Informacoes sobre a Industria Siderurgica." Rio de
Janeiro, 1916.

4 Boverton Redwood and William Topley: "Report on the Riacho Doce and
Camaragibe Shale Deposits on the Coast of Brazil near Macei6." London, 1891.

72 OIL-SHALES AND PETROLEUM PROSPECTS IN BRAZIL

A further examination of the second sample showed 4.7 per cent,
sulfur, and upon distillation it yielded 44.73 gal. of oil and 19.58 gal. of
ammoniacal water per ton. Exposures of these rocks are met with 10 or
15 km. inland in some of the river valleys and along the railway .

Redwood says of these shales: "The presence of sulfur would not,
however, be a serious objection, if the crude oil were used as a liquid fuel
or as a source of gas for illuminating purposes. One ton of such oil would,
if properly burned, afford rather more heat than two tons of good steam
coal, and from each gallon of oil about 90 cu. ft. of 60 candlepower gas
could be produced. Results obtained on the laboratory scale of working
are less satisfactory than those obtained when the shale is distilled on the
manufacturing scale in retorts of suitable construction. The difference
is far greater in the case of the ammoniacal liquor, and a yield of probably
four times the quantity of sulfate of ammonia may be expected."

BAHIA

The better known occurrences of bituminous rocks in this state are
those found in the vicinity of Marahti and southwards along the coast.
The best study of the Marahti deposits is to be found in the paper by Dr.
Gonzaga de Campos, 6 who examined the region in the year 1902. These
rocks occur along the coast in the flat region for considerable distances and
widths. The Marahu deposits are about 30 km. long by about 15 km.
wide. The beds contain both fresh-water and marine fossils. Resting
up against the old crystalline rocks is a fresh- water series of rocks contain-
ing plant remains, which is largely impregnated with bituminous matter.
This is characteristic of the western inland part of the basin. Farther
east, resting on these beds, are found limestones containing marine fossils
and also with impregnations and masses of asphalt; these beds are of
Cretaceous age.

The appearance of the bituminous and carbonaceous material every-
where is notable; these materials occur in the most varied forms. In
these beds are found large solid impregnations having the appearance of
asphalt; at some points the bitumen is viscous like pitch. At Taipu-
mirim, cavities a meter or more in diameter and quite deep are filled with
black bituminous matter. An analysis of this material gave Dr. Gonzaga
de Campos the following: volatile matter, 30.0 per cent.; non-volatile
combustible matter 14.0 per cent.; ash, 56.0 per cent. The material
contains much pyrites. Alcohol dissolves little of it; on evaporation, it
gives a brown rosin. Ether dissolves most of the material and benzol
dissolves it almost completely.

Resting on these Cretaceous beds, a clayey lignite is found in the lower
beds of the Tertiary bluff formation of this coast. In the lowermost

* " Reconhecimento Geologico na Bacia do Rio Merahu, Bahia." Sao Paulo, 1902.

HORACE E. WILLIAMS 73

beds, almost at tide level, the boghead coal known as the " Turf a de
Marahu" is found. This is a most peculiar material, being quite different
from other known bitumens. It is light yellow in color with brown and
gray veins, which appear as stratification planes. The rock separates
along these planes and frequently plant leaves and other fossils of vege-
table origin are found. To the touch, it is rather rough with a felty
texture. It floats and does not absorb water readily. After many days
immersion, it gave a density of 0.925 (mean) with variations between
0.850 and 1.200. On boiling in water, it becomes somewhat elastic to
compression. It is easily cut with the knife and is elastic to a blow from
the hammer, but is readily reduced to a fine light powder. Neither
alcohol nor ether dissolves the material but it is highly bituminous. It
takes fire readily from the lighted match and burns with a yellow smoky
flame. An analysis gave the following: Water (at 110), 2.75 per cent.;
volatile matter, 71.65 per cent.; non-volatile combustible matter, 9.75
per cent. ; mineral residue, 15.85 per cent. The residue consists principally
of silica, much alumina, lime, and grains of quartz. Beds of this
material are exposed for a depth of 3 to 4 m. at the mouth of the Rio
Arimembeca and are said to continue in depth for over 15 m. These
beds are horizontal.

On slow distillation, this material yielded 430 1. of crude oil to the
ton; the density of this oil varies between 0.870 and 0.880. Neither in
color nor aspect does the rock have any resemblance to coal, but the
composition and the products are those of the bituminous coals. It is
not a bituminous schist because the organic material greatly predominates
over the mineral. The great mass of the rock is composed of yellowish
brownish humic material. By fractional distillation, the material gave
the following:

PEB CENT.

Below 150, water strongly charged with pyrolignic acid 10. 00

Yellow wine colored oil (sp. gr. 0.812) 9. 74

Below 270, dark brown greenish oil (sp. gr. 0.840) 21 . 84

Below 350, dark oil (sp. gr. 0.884) 5.74

Residue coke, porous, brilliant, weak 37. 00

Loss 15 . 68

Farther south from Marahu, in the vicinity of Ilhe*os, oil-shales similar
to those of Alagoas are found in several places. These are small ex-
posures of beds that appear along the coast between the granite points,
which hereabouts frequently extend down to the ocean. The area of
these beds seems to be relatively small; and while they are rich in oil
content, then* value remains to be determined. They are under in-
vestigation at the present time. At one of these exposures, near Ilhe'os,
a small still was erected, toward the end of the war, for the extraction
of oil.

74 OIL-SHALES AND PETROLEUM PROSPECTS IN BRAZIL

A region that may prove of more importance and worth while ex-
ploring lies farther south to beyond Caravellas in southern Bahia and
northern Espirito Santo. In this region, over 100 km. long by 50 to 80
km. wide, sedimentary rocks occur and while no oil-shale is reported, the
general geology would indicate that it is probably underlain by the
same shale horizon as that just described. The deposits referred to,
all along the coast, outcrop at or near tide level; in this region they may
be slightly lower and so below that level and not exposed at low water,
for which reason they have never been observed.

The shales about Ilhe'os, as also those of Alagoas, on exposure after
quarrying become warped and separate out into thin paper-like sheets.
These sheets burn readily and frequently contain beautifully preserved
fossil fish. Where more massive and clayey, the shales break into blocks
and are not utilized.

SAO PAULO

The Tertiary basin in eastern Sao Paulo, on the upper reaches of the
Rio Parahyba, is perhaps 150 km. long by 15 to 20 km. wide. Over a
considerable part of this basin, oil-shales have been found. These
shales outcrop 10 to 15 m. above the Parahyba near Trememb6 and
Pindamonhangaba, where they are being mined. Quantities of these
shales have been used at the gas works in Rio and in Sao Paulo at various
times, especially during the war, on account of the shortage of coal.
There exists at Taubate", a small plant for the distillation of oil from
these rocks. These shales also separate into thin paper-like sheets on
exposure and take fire readily from the lighted match. The richer beds
contain quantities of beautifully preserved fossil fish. An analysis gave
the following composition: crude oil, 13.08 per cent.; water, 23.36 per
cent.; gas and loss, 4.02 per cent.; mineral residue, 58.64 per cent. On
slow distillation these shales yielded 27 gal. of crude oil per ton. How-
ever, at the plant that existed at TaubatS many years ago, only about
17 gal. were extracted.

SOUTHERN BRAZIL

Extending through Sao Paulo, Parand, Santa Catharina, Rio Grande
do Sul, and into Uruguay 6 is a very persistent bed of black petroliferous
shale in the upper Permian series of rocks. This bed of shale was named
the Iraty Black Shale by Dr. I. C. White 7 from its occurrence near the
station of Iraty on the Sao Paulo Rio Grande railway. A freshly broken
specimen of this shale generally gives off a strong odor of petroleum.

6 E. P. de Oliveira: Regioes Carboniferas dos Estados do Sul. Service Geologico,
Rio de Janeiro, 1918.

7 "Final Report of the Brazilian Coal Commission." Rio de Janeiro, 1908;
The Coals of Brazil. Second Pan-American Congress, 1916.

HORACE E. WILLIAMS 75

At places, the petroleum of these shales has been oxidized into al-
bertite or other substance resembling coal, as about Piracicaba and Rio
Claro in the state of Sao Paulo. Material rich in oil is found between Sao
Pedro and Piracicaba in beds of considerable thickness. A company
has been formed recently in the city of Sao Paulo for explorations in this
region. Near Rio Claro, several miles farther north, some drilling has
been done during the last few years.

At about the same geological horizon as the above outcrops, but at
a much lower level, deposits of asphalt occur along the Rio Tiete* near
Porto Martins. Farther south, in the foot hills of the Serra de Luiz
Maximo between Tatuhy and Botucatu, a heavy bed of bituminous
sandstone is found some distance above the black shale. An analysis
of this rock showed 15 per cent, bituminous matter. This sandstone
seems to represent the oxidized and eroded remains of a former pool.
Small deposits of asphalt occur at different places in Parand, and Santa
Catharina. Recently a plant has been installed near Sao Gabriel, in
Rio Grande do Sul, for the distillation of oil from these shales.

Analyses of the black petroliferous shale and the albertite, as given in
Doctor White's report, are as follows:

PETROLIFEROUS
SHALE, PER CENT.

Moisture

Volatile matter.
Fixed carbon . . .
Ash..

Petroline

Asphaltine

Non-bituminous organic matter.
Ash..

These black shales outcrop in the plains region and among the foot
hills along the east scarp of the great interior plateau. Farther south,
this scarp gradually approaches the coast in Santa Catharina and then
swings back west and southwest across Rio Grande do Sul. The rocks
generally have a low westerly dip but the whole region has been some-
what faulted and folded and is cut by dikes of eruptives from which
extruded the great flows of trap covering large parts of the interior.

The region west of the interior scarp has been indifferently mapped
and almost no work has been done in studying the geological structure of
the underlying rocks. The region merits study. It seems clear that no
pools are to be expected east of the mountain scarp (the strata in which
they might have occurred having been removed by erosion, as near the
Serra de Luiz Maximo above noted) but conditions may exist farther

76 OIL-SHALES AND PETROLEUM PROSPECTS IN BRAZIL

west somewhere in this vast region favorable for the accumulation of
such pools.

While extensive faulting and fissuring of the strata of this region may
have allowed the escape of contained petroleum in their vicinity, these
are neither so numerous nor so wide spread as to preclude its existence
in other places. If one may judge by many examples known today,
important deposits may still be present in the strata even in the vicinity
of eruptive dikes. Be this as it may with regard to petroleum, the fact
is abundantly demonstrated that, in these shales, Brazil has an inex-
haustible supply which .only requires suitable processing to become
available.

DISCUSSION

RALPH ARNOLD, Los "Angeles, Calif. The newspapers state that the
Brazilian government is contemplating putting into effect rules and regu-
lations for the oil business. I think this is a pretty good sign that there is
oil in Brazil.

DAVID WHITE, Washington, D. C. Oil-shales of the Tertiary age
have long been known in the Province of Bahia. Bog heads extremely
rich and comparable in constitution to the "kerosene shale" of New
South Wales are reported to have been found in the coal measures of
Santa Catarina and Rio Grande do Sul. Such Permian bogheads, which I
examined at the time Dr. I. C. White was investigating the Brazilian
coal fields, were, in fact, found to be so far identical paleontologically
with the Australian rock as to arouse suspicion as to the genuineness of the
Brazilian source of the material, as was noted in the report. Richly
bituminous shales are, however, credibly reported to be present in great
thickness in a formation of Triassic age in Brazil.

J. ELMER THOMAS, San Antonio, Tex. 1 saw recently a private
report on an oil-shale occurrence in Santa Catarina. While not made by
a recognized expert, it was an extremely detailed and careful report and
called attention to one large deposit within 100 miles of the coast and
midway between Buenos Ayres and Rio de Janeiro. Oil at this point
is worth about $8 per barrel. The deposit was believed to be extensive
and outcrops in a cliff to a thickness of 70 ft. Samples of the oil
had been distilled in this country and showed a good gasoline content
as well as kerosene, lubricating oil, and gas oil. The estimated yield
was high, from 35 to 40 gal. per ton. It seems probable that an occur-
rence of this nature will be developed soon, as its economic importance
is considerable.

JOHN C. BRANNER,* Stanford University, Calif . (written discussion).
The theory of the possible existence of oil-bearing formations in the upper

* President Emeritus.

DISCUSSION 77

Amazon region is a perfectly legitimate inference based on the known oil-
bearing horizon in regions farther north, but it lacks the support of all
the necessary facts. That region, however, is covered by dense tropical
forests and is difficult of access on account of its great distance from the
coast and the difficult navigation of the upper reaches of the Amazon
River. Also, white races cannot remain in it long with impunity. Only
a company with unlimited means could undertake the exploration and
exploitation of such an area. The population is sparse and confined to the
small towns along the larger streams.

In addition, the mining laws of Brazil do not encourage the develop-
ment of these regions. In Decree No. 2933, January, 1915, article 42,
paragraph 1 says that a mining claim shall contain 5 hectares (12.3 acres)
and that the greatest number of claims that may be conceded to a single
individual or organization for petroleum is 20 claims but "for the purposes
of mining operations the limits shall be 40 claims" for petroleum. I have
been informed that efforts are being made to revise the mining laws for
the purpose of encouraging the development of that country's mineral
resources but I do not know the result of these efforts. A proposed new
mining law was published at Rio de Janeiro, Dec. 8, 1917, but 1 do not
know if it was passed. This law provided that the unit of a claim
shall be a hectare but that the number of hectares " that may be granted
for each type of mineral deposit shall be established by the regulations
for the enforcement of this law." These regulations are not published
with the proposed law.

No one acquainted with the peculiarities of petroleum deposits of
other parts of the world would venture the large capital necessary in a
new and untried field for the sake of what he could reasonably expect to
obtain from 100 acres of land.

Since the above was written I have received from one of the best
posted legislators in Brazil the following information:

The laws now in force are those of Decree No. 2933 of Jan. 6, 1915.
The provision of Art. 42, par. 1, of that decree relating to mining claims
(lote de lavra) refer only to lands controlled by the Federal Government;
and inasmuch as the Federal Government controls only limited areas,
this provision is of little importance in its bearing on petroleum lands.
When considerable areas are required for the development of petroleum
fields, they may be obtained from the landowners by lease or purchase
very much as such lands are secured in the United States.

78 INTERNATIONAL ASPECTS OF THE PETROLEUM INDUSTRY

International Aspects of the Petroleum Industry

BY VAN H. MANNING,* WASHINGTON, D. C.
(New York Meeting.'February, 1920)

IN SUBSTANCE, the international aspects of the petroleum industry,
as these relate to the United States, are as follows: The domestic pro-
duction is not keeping pace with the domestic demands; our best
engineering talent warns us of the imminence of a decreased production by
our oil wells, although more oil is needed; and the only practical source
whence this increasing demand can be supplied for some time to come
will be the foreign fields. Other nations have given thought to the future
and, in recent years, have shown a tendency to adopt strong nationalistic
policies regarding their petroleum resources, policies that hinder or
prevent the exploitation of these resources by other nationals. In con-
sequence, we find that, facing a probable shortage of the domestic supply,
our nationals are excluded from foreign fields; and this in spite of the
fact that foreign nationals have been permitted to enter into and exploit
our own oil resources on an equality with American citizens and without
hindrance or restrictions. This country has supplied the larger part of
the petroleum consumed by the world and yet, with a failing supply
imminent, it finds that those countries that have been drawing upon our
resources to supply their needs are showing a tendency to exclude us from
their resources. In this way we shall be transferred from a position of
dominence to one of dependence; and only by sufferance of those countries
that are now seeking financial or political control of petroleum supplies,
shall we be able to obtain the oil we will need.

IMPORTANCE OF PETROLEUM

Petroleum has become, during recent years, one of the essentials
of our social and industrial life. All civilized countries recognize that
the world is dependent on petroleum as on nothing else except textiles,
foodstuffs, coal, and iron. Today, the tendency is toward an ever-
increasing consumption of petroleum and its products as new and more
efficient uses are found for them. The*utilization of petroleum is extend-
ing more and more into the structure of our civilization. Consequently,

* Director, U. S. Bureau of Mines.

VAN H. MANNING 79

it becomes a matter of the gravest concern whether we can go on build-
ing up an industrial and social structure dependent on petroleum unless
we make provision for obtaining the necessary supplies. Unlike food-
stuffs and textiles, the world's supply of petroleum is definitely limited;
moreover, it is, like coal and iron resources, a wasting asset. But petro-
leum is a liquid, is by nature migratory, can be quickly extracted, and an
oil field is readily exhausted; whereas coal and iron are extracted more
slowly and, by prospecting, reserves can be blocked out for the years
ahead. Oil fields once discovered are developed almost immediately;
within a short time the peak of production is passed and decline sets in.
We are constantly relying upon the discovery of new fields, at the moment
unknown, to make up for the decline and depletion of those that are
proved. Thus, we are living a hand-to-mouth existence and although
during the past decades we have been very fortunate in making opportune
discoveries first Gushing, then Kansas, and then northern Texas
each of which has made up for a threatened deficit, the time must inevi-
tably come when fortune will forsake us and the needed new production
will not materialize. Then we may find ourselves suddenly thrown upon
the mercy of the nations that control foreign sources of supply.

Few of us realize in how many ways petroleum products serve our
daily needs. Petroleum in one form or another is used in every household ;
gasoline for the motor car, lubricating oils for bearings, kerosene lamps or
paraffin candles for illumination. Not one of us can sit back and say
that an adequate supply of petroleum is not a personal concern. Perhaps
a recent statement appearing from enemy sources may convey most con-
vincingly the importance of petroleum in modern life. Ludendorff, in
his book on the late war, in speaking of the Rumanian campaign, says,
"As I now see clearly, we should not have been able to exist, much less
carry on the war, without Rumania's corn and oil, even though we had
saved the Galician oil fields from the Russians."

IMPORTANCE OF INDUSTRY

During the world war, the Navy demonstrated the value of petroleum
as marine fuel. Having a higher heating value than coal, a given tonnage
assures a ship a much wider cruising range before refueling. In the
mercantile marine the smaller bulk of fuel provides larger cargo space in
the hull. Cleanliness and less labor for loading and burning are two other
important features. In consequence, new ships are being built to burn
oil and old vessels are being changed from coal to oil burners. Our
greatest maritime rivals, the British, are rapidly equipping their merchant
marine to burn oil, so that it has become obligatory upon the United
States Shipping Board to do likewise in order that our vessels may be able
to compete on an equal basis, as regards fuel, with foreign-owned bottoms.

80 INTERNATIONAL ASPECTS OF THE PETROLEUM INDUSTRY

The production, refining, and distribution of petroleum and petro-
leum products is one of our greatest industries; it provides a livelihood
for many thousands of families. Although it has offered a big field for
the engineer and chemist, in my opinion it has been comparatively un-
exploited by the mining engineer and is capable of absorbing hundreds, if
not thousands, of properly trained and experienced engineers.

The oil industry also provides a wonderful field for our chemical
engineers. Petroleum can be considered as a crude chemical, like coal tar,
and the fuel value of all its products and the most efficient methods of
utilizing them have not been discovered by any means.

Not only has petroleum furnished useful and essential products, but
industries based upon these products rank among the major activities
of the nation. Of such dependent industries, the greatest is the auto-
motive industry. The automobile, the truck, the tractor and the air-
plane enter into our daily life. Today more than 6,000,000 automobiles
are in use in the United States alone.

The three most important utilizations of petroleum are as fuel, as an
illuminant, and as a lubricant. Petroleum fuels may be classified as light
and heavy. The light fuels are gasoline, naphtha, and kerosene, which
can be vaporized and used in the internal-combustion engine of the auto-
mobile or tractor. Heavy fuels are those that are burned directly for
steam raising or for heating purposes, or can be used in internal-combus-
tion engines of the Diesel type. About 57 per cent, of our output of
crude petroleum is oil fuel of the heavy type, only a small proportion of
which is used in internal-combustion engines; the other uses are relatively
inefficient and for such uses petroleum is replaceable by coal. A larger
use of this heavy fuel in the internal-combustion engine is hopefully
expected, but with this development, the dependence of the world on
petroleum will be increased still further.

This country is not as dependent upon petroleum illuminants as it
was, although kerosene still is used in large quantities in districts not
served by gas or electricity, and is an article of great importance in our
trade with foreign countries.

Petroleum lubricants, although less in amount than the other prod-
ucts, are more generally used and are really more essential. They lub-
ricate practically all bearings or moving parts. Quantitatively, there are
no satisfactory substitutes and when one starts to replace, on a large
scale, mineral lubricants by animal or vegetable oils of satisfactory qual-
ity, the dependence of our industrial life on petroleum lubricants becomes
evident.

When we realize what petroleum, directly and indirectly, has done for
our country and when we try to see what improvements in our ways of
living the future holds for us, the significance of the international aspects
of the petroleum industry becomes clearly evident. When we consider

VAN H. MANNING 81

the number of automobiles turned out yearly, the airplanes that will play
an important part in commerce, the trucks that will supplement present
transportation facilities, the agricultural machinery needed to meet the
lack of man power on our farms, and the relation of our merchant marine
program to oil, we can understand how vitally necessary an adequate
supply of petroleum will be to us.

OUR PETROLEUM RESOURCES

The United States was the first country to produce oil in large quan-
tity by the modern system of drilling wells and, except during a few
years, has led all the countries of the world in the quantity of its produc-
tion. In 1914, when the World War began, the United States was in
first place and produced approximately 266,000,000 bbl. of oil, or
about 66 per cent, of the total output of the world. Russia was second,
with an approximate production of 67,000,000 bbl., or about 17 per cent,
of the world's total. Mexico came third with about 21,000,000 bbl.,
or a little over 5 per cent, of the world's production. Rumania, the
Dutch East Indies, India, Galicia, Japan produced comparatively small
amounts of oil, totaling approximately 12 per cent.

In 1914, therefore, the United States was far ahead of any other
nation as a producer of oil. It was also far ahead of any other in the
development of its oil fields and in the utilization of oil products. The
vital importance of petroleum had not been fully recognized by the lead-
ing countries of the world, so the United States occupied a unique posi-
tion, practically without competitors. Foreign countries had not begun
to consider seriously future supply and there was less rivalry in gaining
control of possible oil fields. Yet signs of an awakening interest were
evident. Great Britain, because of having adopted fuel oil in the Navy,
had begun taking steps to assure, through British nationals, an adequate
supply of oil from Mexico and to encourage development in British
domains. The British Government had also entered into partnership
with the Anglo-Persian Oil Co. to exploit a huge concession in Persia.

The point of real importance, however, is the relative position of the
United States as a consumer rather than a producer of oil. To produce the
bulk of the world's production is of small consequence in comparison with
producing enough to meet our present and probable future needs. In
1918, the output of crude oil in the United States was 356,000,000 bbl.
Mexico had taken second place with 63,000,000 bbl. The production of
the United States for the past several years has been approximately 65
per cent, of the world's total. The approximate consumption of the
United States for the year 1918 was 418,000,000 bbl., or more than 80
per cent, of the world's production. This figure of consumption, however,
includes the oil that was refined or partly refined in the United States and

VOL. LXV. 6

82 INTERNATIONAL ASPECTS OP THE PETROLEUM INDUSTRY

exported for consumption abroad. The exports of petroleum products
approximated the imports of crude petroleum from Mexico and other
foreign countries. But in addition, some 20,000,000 bbl. of oil were
withdrawn from domestic storage. In substance, therefore, the United
States, in 1918, was living beyond its means. The year 1919, because of
the present flush production from Texas fields and the increased imports
from Mexico, finds the United States in a somewhat more favorable condi-
tion, not having to draw on stocks; yet it must be remembered that the
stocks have not only decreased actually but have decreased in proportion
to our production and consumption. Thus, in 1915, there was over six
months' supply of oil in storage, whereas at the end of 1918 stocks had
been reduced to less than four months' supply.

The U. S. Geological Survey has given the following figures of the mar-
keted production and consumption in the United States. The figures
for marketed production approximate, but are not the same as, actual
production:

MABKETED PRO- CONSUMPTION,

DUCTION, BARRELS BARRELS

1916 301,000,000 329,000,000

1917 335,000,000 384,000,000

1918 356,000,000 418,000,000

Evidently the production of the United States, in spite of its having
risen steadily during recent years, is not rising as rapidly as it should and
is not keeping pace with the increase in consumption. The sources from
which we can draw for our future needs of petroleum and its products are :
Our own oil fields, foreign oil fields, oil shales, and substitutes for petro-
leum products. Engineers and geologists who have investigated the
possible oil underground in our developed and undeveloped oil fields
agree in making pessimistic reports. This is particularly true of the U. S.
Geological Survey, the organization that has given most attention to our
petroleum resources and has the most facts. The U. S. Geological Sur-
vey estimates our unproduced but recoverable oil in January, 1919, at
6,740,000,000 bbl. This, could it be produced as needed, would not con-
tinue our present production of oil for more than 20 years.

Many persons, especially non-technical oil men, are inclined to ques-
tion these estimates and call them too pessimistic, saying that whenever
in the past more oil was needed new discoveries were made and unexpected
fields brought forth new supplies. However, our best-informed engineers
have given this estimate, and their belief should outweigh the vague optim-
ism of those who question it. Of course, in view of the fallibility of estimates,
the figures may prove to be too pessimistic. Even if the estimates of the
supply of unrecovered petroleum were 50 to 100 per cent, too low, the
situation would still not be satisfactory. And the fact remains that no

VAN H. MANNING 83

matter how much oil there may still be in the ground, we have not been
and are not getting it to the surface as fast as it is now needed.

Clearly, we must seek other sources of supply to make up the balance
between domestic production and domestic needs. Enormous deposits
of oil-bearing shales occur in the western states, in the Cretaceous forma-
tions of the Rocky Mountain region. The U. S. Geological Survey esti-
mates that the shales in the states of Colorado, Wyoming, and Utah alone
contain many times the recoverable oil present in our oil fields before well
drilling began. But the oil in these shales is not immediately available.
The extraction of oil from the shales on a commercial scale under existing
conditions in the United States is still in an experimental stage. We do
not know, as yet, whether these shales can be developed profitably under
present conditions, nor under what conditions they can be developed.
Furthermore, it will take many years, even under favorable conditions,
to obtain from these shales enough oil to replace a considerable part of
that now obtained from wells.

I do not wish these statements to be interpreted as reflecting on the
prospects of the shale industry, but simply wish you to realize that the
production of oil in the quantities demanded by present-time needs would
require development on a tremenduous scale and would require the mining
of hundreds of millions of tons of shale each year, the annual amount
being more than half the annual tonnage of coal now mined. There is
no evidence that shale oil can be produced on such a scale at present prices
and, therefore, to satisfy our petroleum needs by oils from shales involves
higher prices for petroleum products. Moreover, our oil shales occur in
sparsely populated regions, remote from centers of large consumption.
Oil shales constitute a reserve that, fortunately, seems to provide ample
protection against an ultimate future but they cannot be used to meet
the present situation.

SUBSTITUTES

The products from the destructive distillation of coal can be used,
in so far as they are available, to replace gasoline; but quantitatively it
seems out of the question to expect more than a minor alleviation from
them. Coal can largely replace fuel oils. Alcohol can replace gasoline
and has the advantage that it can be made from replaceable material
that is, from plants, but because of its cost, it cannot compete in a large
way with gasoline at present. Moreover, the difficulty and expense of
replacing any considerable part of the gasoline supply by alcohol is not
generally appreciated. Finally, no substitutes are now known that will
satisfactorily replace mineral lubricants in the quantities needed.

Thus, the facts indicate that we must inevitably seek foreign supplies
in order to meet our needs and to compete in the world's markets with-

84 INTERNATIONAL ASPECTS OF THE PETROLEUM INDUSTRY

out too great a handicap. However, we should not rely upon any one
solution of the problem, but should seek to put into effect every feasible
means that promises to help, and should strive to anticipate our future
needs rather than to go along blindly with the inevitable result of sud-
denly being confronted at some future date with a shortage of oil. Steps
should be taken to conserve our developed supply. This supply is tangi-
ble; we already have it, and common sense dictates that we take the best
possible care of it. By conservation I do not mean the tying up of re-
sources, but a wise utilization, the working out of methods that will
yield us the greatest quantity of oil at the least cost and will enable us
to refine and use the oil with the highest efficiency. This phase of the
question is peculiarly a part of the work of technical men, and I believe
that this Institute should seriously endeavor to further, in every possible
manner, the application of engineering methods to the oil business, for
the oil industry is probably more backward in applying engineering
knowledge than any other mineral industry. This statement is not a
criticism of the oil industry for being backward in taking up engineering,
any more than it is a criticism of the engineer in being backward in taking
up the oil industry. Until recently there were few engineers who were
qualified, by actual experience in the oil fields as well as by engineering
training, to be of real assistance to the industry. Happily, this condition
is rapidly improving. Yet there is today an under supply of competent
petroleum engineers equipped to deal with practical problems.

In addition, we should further the oil-shale industry and, regardless
of our individual opinions, should endeavor to determine as soon as pos-
sible under what conditions the oil-shale industry is commercially feasible,
and thus be prepared for a future emergency.

In the same way, petroleum substitutes should not be neglected
These lie mainly in the field of the chemical engineer rather than of that
the mining engineer.

FOREIGN SOURCES OF SUPPLY

Recently, the U. S. Geological Survey has shown a particular interest
in questions of foreign supply, and has rendered a splendid public service
by collecting all possible information on the subject. This information
has been placed at the disposal of the government and also of those in-
dividuals who contemplate entering foreign fields. .

In the opinion of the U. S. Geological Survey, enormous resources
await development in various parts of the world; but these resources have
not been developed as intensively as those of the United States. The
premier position of the United States to the present time has been due,
perhaps, more to an intensive development of resources than to any
supremacy in the resources themselves. Enough information is available
about foreign countries to know that oil occurs in many places, and that

VAN H. MANNING 85

there are partly developed fields of high promise. It may well be that
in vast areas which have not been studied by the geologist or tested by
the prospector there are undiscovered fields of great magnitude. For
these reasons I believe that there is not nearly as much danger of a world
shortage as there is of a domestic shortage. Fortunately, the situation
requires nothing more than the developing of foreign fields as supplies are
needed and the accessibility of those fields to our nationals. The problem
that presents itself, therefore, is whether the United States can obtain
an adequate share of oil from the known and potential fields of. the world,
or whether it is going to be excluded by the political and economic policies
of other nations and thus find itself, so far as petroleum is concerned, at
the mercy of those nations.

The key to the future is access to the sources of supply. The strong
financial position of the petroleum industry, in this country, the refining
and marketing facilities of the strongest American companies will not,
by themselves, suffice if we are at the mercy of the citizens of other nations
for our crude supplies.

STRONG NATIONALISTIC TENDENCY OF FOREIGN COUNTRIES TO
EXCLUDE OTHER NATIONALS

One result of the war has been an accentuation of nationalistic spirit;
the nations that were combatants and those that were neutral have shown
increasingly a tendency to exclude other nationals from their domains and
to develop their own resources by their own interests. This tendency is
a natural result of an awakened knowledge of the need of self -protection
and of a desire to conserve for themselves the materials now essential to
the world's civilization.

The United States is not an imperialistic nation, and, exclusive of
Alaska, its foreign possessions are with small potential resources. Thus
we find no political control of consequence over other than the domestic
sources of supply within the United States proper.

When we turn to the developed or prospective oil fields in other parts
of the world, we find that their political control may be grouped under two
heads: colonies and domains of such nations as England and France,
and domains of smaller nations, such as the Latin-American countries,
China and Persia; under present chaotic conditions perhaps Russia could
be included. The most promising oil districts now known outside of the
United States are in Mexico, in the South American countries bordering
the Caribbean, in Equador, Peru, Bolivia, Argentina, northern Africa,
Egypt, Persia, Mesopotamia, Palestine, Russia, India, East Indies, and
China. There are other localities of smaller promise or about which less
is known, and doubtless some of these will develop fields of the first
magnitude when explored and prospected.

When one reviews these potential oil fields, one is struck with the

86 INTERNATIONAL ASPECTS OP THE PETROLEUM INDUSTRY

fact that Latin America, Great Britain, France, and the Netherlands,
apparently control the main potential sources of supply, and particularly
those that are of the most concern to the United States. Thus, the poli-
cies of these countries are of the greatest interest to America. We find
England and France adopting policies, already in part incorporated into
laws or regulations, that now virtually exclude other than their own
nationals from developing the resources within their own realms. Of
course I do not mean to insinuate that the policies of these countries are
aimed directly at Americans; the policy of each country is to look after
its own citizens; hence it is directed against the citizens of all other
countries, and thus affects Americans. For a detailed statement regard-
ing the policies of these countries I refer to a memorandum by myself
to the President, which was disclosed to the United States Senate by Sena-
tor Phelan of California. Copies of this document appear in the Con-
gressional Record of July 29, 1919. Those interested in the various
political phases of the situation can obtain information there, or from the
American Petroleum Institute.

The members of this Institute are well informed as to the situation in
Mexico. Mexico is considering stringent regulations as to oil concessions
which, if enacted into law will be very detrimental to the just interests of
nationals other than Mexicans, including ourselves. The policy of
Argentina has been, practically, the nationalization of its petroleum re-
sources. Other Latin-American countries have shown some uncertainty
as to what their policies are to be. Japan has adopted a policy that
practically excludes other nationals from its own fields in Japan, Formosa,
the Island of Sakhalin, and from the fields of China so far as its control
extends. The Netherlands Government has also adopted a policy of ex-
clusion that practically restricts developments within its domains to its
own nationals. France has adopted policies that are not so evident on
the surface, but in effect, these policies are proving restrictive, and are
seemingly intended to exclude other nationals.

RECIPROCAL PRIVILEGES SHOULD BE GIVEN TO AMERICAN

NATIONALS

A review of the foreign situation, therefore, discloses the fact that
whereas other nationals can enter our oil fields, acquire properties there,
and work these properties on an equality with ourselves, our nationals
are not receiving reciprocal privileges from many foreign governments
now controlling the most important oil regions of the world, and thus in
time we are likely to be largely dependent on those governments for our
domestic needs. Moreover, conditions in the Latin-American countries
are not as satisfactory as they might be. The question comes, therefore,
as to what should be done toward removing discrimination under which
Americans are practically excluded from foreign oil fields. It is not for

DISCUSSION 87

me to discuss here such a question in detail, but it is perfectly obvious
that in all fairness our nationals should be accorded the same privileges
that we accord other nationals. It has not been the policy of the United
States to exclude foreign corporations or individuals; in fact, they have
been welcomed, as it has been recognized that the capital brought in has
been, in a large way, helpful to the United States even though the profits
went mostly to the benefit of other nationals. It would be, in my opin-
ion, a mistake to forsake this policy, just as I believe it is a mistake on
the part of other nationals to have put into effect such policies. It
would be desirable if all countries adopted the same open policy as that
which has prevailed in the United States.

In regard to individual Americans, and particularly to the members
of this Institute, it seems to me that it is the duty of all to interest them-
selves in the situation and to do what they can to educate the people of
this country and their representatives as to the situation, and to urge
such wise and necessary steps as would best relieve it.

Another help that the members of this Institute can render is to
transmit to the government such information as it acquires on the foreign
situation, including information on the possibilities of oil fields, on laws,
regulations, and policies that tend to discriminate against American
nationals entering foreign fields, and on actual cases of discrimination.
This information built up from many sources will prove invaluable to the
government, and thus to yourselves and those interested in the foreign
oil fields. I do not know whether the furtherance of such work could be
made properly a part of this Institute collectively, but I see no reason why
the members of this Institute should not render this service to their
government.

I may also urge the opportunities and national importance of Ameri-
can concerns entering foreign oil fields. Evidently this country is going
to need foreign sources of supply, and it will be to its great advantage to
obtain these through its own nationals. Heretofore, American methods,
American machinery, American brains have been employed by foreign
capital to develop foreign resources. It will be more desirable if our
brains and abilities are employed under our own nationals. It is desir-
able that every engineer realize before accepting employment with any
foreign corporations competing against ours, just what this means. I
believe it should be made a policy of the members of this Institute to see
that the younger engineers and those unacquainted with foreign condi-
tions, are informed on this matter.

DISCUSSION

LEONARD WALDO, New York, N. Y. In Mexico, there are huge oil
resources, but the only means of transmitting that oil to the United
States is by ship, and ships seem to be forgotten on all occasions. Those

88 INTERNATIONAL ASPECTS OF THE PETROLEUM INDUSTRY

we had at the beginning of the war for carrying oil were almost all under
foreign charters, which were soon recalled and the ships used for trans-
porting oil from Mexico and other points to Europe. Consequently, now
we have a scarcity of ships for carrying oil ; that is the most important
defect in fueling the Atlantic seaboard. Every effort should be made to
bring the shipping interests into line, including the government shipping.
Oil is the one way of fueling the Atlantic seaboard and taking care of
our steel plants, our boiler plants, our heavy industries that take oil,
and ships must be used to relieve the pressure from the oil lines, which
are only capable of supplying the higher uses of oil at 20 or 30 cents a
gallon. For fuel, the marketable value of oil should be about 2 cents a
gallon; before the war, large contracts were made at 1.8 cents per gallon
for Mexican fuel oil delivered at the docks for the steel works to use.

A FOREIGN OIL SUPPLY FOR THE UNITED STATES 89

A Foreign Oil Supply for the United States

BY GEORGE OTIS SMITH,* PH. D., WASHINGTON, D. C.

(New York Meeting, February, 1920)

TWELVE years ago, the Director of the United States Geological Sur-
vey addressed to the Secretary of the Interior a letter calling attention to
the government's need for liquid fuel for naval use and pointing out that
the rate of increase in demand was more rapid than the increase in pro-
duction. 1 This letter, in a way, inaugurated the policy of public oil-
land withdrawals, which was well founded in its primary purpose of
protecting the oil industry and highly desirable in its immediate effect
of checking the over-development of that day in California. Unfortu-
nately, however, through delays in legislation, this policy may be regarded
now as having outlived both its intent and its usefulness. In 1908, the
country's production of oil was 178,500,000 bbl., and there was a sur-
plus above consumption of more than 20,000,000 bbl. available to
go into storage. In 1918, 10 years later, the oil wells of the United
States yielded 356,000,000 bbl. nearly twice the yield of 1908 but to
meet the demands of the increased consumption more than 24,000,000
bbl. had to be drawn from storage.

Nor is this all of the brief comparison. In 1918, our excess of imports
over exports of crude petroleum was nearly 33,000,000 bbl. whereas in
1908 we exported 3,500,000 bbl., which was net, as we had not begun to
import Mexican oil. In this period, the annual fuel-oil consumption
of the railroads alone has increased from 16,871,000 to 36,714,000 bbl.;
the annual gasoline production from 540,000,000 gal. to 3,500,000,000
gal. This record may be taken not only as justifying the earlier appeal
for Federal action, but as warranting deliberate attention to the oil
problem of today.

NEED OF FUTURE SUPPLY

The position of the United States in regard to oil can best be charac-
terized as precarious. Using more than one-third of a billion barrels a
year, we are drawing not only from the underground pools but also from
storage, and both of these supplies are limited. In 1918, the contribu-

* Director, U. S. Geol. Survey.

1 This letter, drafted by Dr. Ralph Arnold and concurred in by Dr. C. W. Hayes
and Dr. D. T. Day, is quoted in Bull 623, U. S. Geol. Survey, 104.

90 A FOREIGN OIL SUPPLY FOR THE UNITED STATES

tion direct from our wells was 356,000,000 bbl., or more than one-twen-
tieth of the amount estimated by the Survey geologists as the content of
our underground reserve; we also drew from storage 24,000,000 bbl., or
nearly one-fifth of what remains above ground. Even if there be no
further increase in output due to increased demand, is not this a pace
that will kill the industry? Even though we glory in the fact that we
contributed 80 per cent, of the great quantity needed to meet the require-
ments of the Allies during the war, is not our world leadership more spec-
tacular than safe? And even though the United States may today be
the largest oil producer and though it consumes nearly 75 per cent, of
the world's output of oil, it is not a minute too early to take counsel with
ourselves and call the attention of the American geologists, engineers,
capitalists and legislators to the need of an oil supply for the future.

This appeal to American brains and American dollars to provide for
the future needs only the backing of a brief recital of the facts of known
present needs and of well-justified expectations for the future. In a
single decade, then, the consumption of fuel oil by railroads has more than
doubled; the consumption of gasoline has increased sevenfold. With
the rapidly mounting cost of coal, the competitive field of fuel oil for
steam use is expanding. But not only is the use of oil, both under
boilers and in internal-combustion engines, thus increasing, there is
an even more widespread use of a petroleum product, which was brought
to the President's attention over 10 years ago. 2 Every new instal-
lation of machinery, whether the 60,000-kw. generator in the Govern-
ment nitrate plant at Sheffield, Ala., or the 20-hp. motor in the small
automobile, adds to the country's demand for lubricating oil, which is an
essential in every phase of modern civilization. We may lessen the
increase in coal or oil consumption for generating power by harnessing
the water powers of the country; but these prime movers, whether
driven by steam or water, require lubrication. With the rapidly in-
creasing use of machinery to make labor more productive, with the
almost universal use of the automobile, hardly foreseen a decade ago,
and with the expected increase in railroad and steamship traffic, who
can venture an estimate of our petroleum requirements, 10 years hence,
in terms of lubricatin oil alone?

A most serious aspect of our oil problem presents itself when we con-
sider the entry of the United States as a real factor in the shipping of the
world when we picture the return of the American flag to the seven
seas. Any nation which today aspires to a large part in world commerce
imposes upon itself an oil problem, for the future freedom of both the sea
and the air will be defined in terms of oil supply. The new demand of
our shipping program alone involves fuel oil in quantities equivalent

* Letter quoted in full in Bull. 623, U. S. Geol. Survey, 134.

GEORGE OTIS SMITH 91

to nearly one-half of the present domestic output, and, unless there is
some corresponding decrease in other demands, this new requirement
must be met with an increase in production of crude oil of nearly 200,000-
000 bbl. How can such quantities of oil be supplied? Mr. Requa's
earlier estimate of 52 ; COO,000 bbl. as the annual gain in output needed
to meet the ordinary increase in consumption and to offset the expected
decline in old wells would involve a task laid upon our oil companies, in
their exploration and development activity, of bringing in a million-
barrel new production each week. How can the oil fields of the United
States maintain such a curve of new production?

Fuel oil, gasoline, lubricating oil for these three essentials are there
no practical substitutes or other adequate sources? The obvious answer
is in terms of cost; the real answer is in terms of man power. On land
and on sea, fuel oil is preferred to coal because it requires fewer firemen;
and back of that, in the man power required in its mining, preparation,
and transportation, the advantage on the side of oil is even greater. So
too, the substitute for gasoline in internal-combustion engines, whether
alcohol or benzol, means higher cost and larger expenditure of labor in
its production. While we have great reserves of oil shales as an inde-
pendent source of fuel oil, gasoline, and lubricating oil, it is necessary
to consider the practical contingency suggested by Mr. Requa, that to
develop this supply on a scale comparable in output with our present oil
supply "would require an industrial organization greater than our entire
coal-mining organization." Plainly our country cannot afford to sup-
port another such army of workers until we reach another stage in our
industrial development.

A country-wide thrift campaign needs to be waged looking to the
saving for this essential resource. Man power and oil ought to be con-
served all along the line of production and consumption by better methods
in the discovery, drilling, recovery, transportation, refining, and use of
petroleum and its products. Unwarranted optimism, which seems
indigenous in most parts of the United States, has led both the oil indus-
try and the public to waste this best of fuels; the program of wastage
begins with leakage below ground and above ground and continues to the
indiscriminate burning of fuel oil under boilers, with regard for con-
venience rather than for efficiency.

The estimate by the United States Geological Survey of the oil re-
maining in the ground is of necessity subject to criticism as speculative
it must contain errors in the allowances made for isolated and undeveloped
fields yet the excesses of unexpected yield in one region will largely be
balanced by deficiencies in another. Indeed, as has been suggested by
the Chief Geologist of the Survey, if happily the estimate of reserve proves
too low, this unpredicted abundance would surely raise the consumption
rate. On the whole, he believes it fair to consider the official estimate of

92 A FOREIGN OIL SUPPLY FOR THE UNITED STATES

6,500,000,000 bbl. as conservative and 8,000,000,000 as an improbable
maximum. The difference between these two estimates of reserves
represents only four years' supply, even at the present rate of consumption.

It seems almost as if divine providence, by the Gushing and Healdton
"strikes," replenished our supply of oil "in storage" just in time to enable
us to export oil and gasoline in quantities sufficient to justify Earl Cur-
zon's statement that the "Allied fleets floated to victory on a sea of oil;"
and the Ranger discovery was equally providential; yet the motto in-
scribed on our silver coins should hardly be made our national policy
in providing a future oil supply.

It cannot be pointed out too often that while in the last 100 years
the unprecedented growth in the industrial and transportation demands
of our country has resulted only in the exhaustion of less than 1 per cent,
of its coal resources, in the 60 years since the Drake well began our pro-
duction apparently 40 per cent, of the available oil has been brought to
the surface and consumed; and the rate of America's development is still
an accelerating rate. American interests, commercial and industrial,
thus require a future supply of crude oil outside the United States.
Indeed, we have been draining our own oil pools in part to supply the
needs of the rest of the world, but have made little effort to render
the rest of the world self-supporting in oil production. Whether such a
national policy is to be characterized as that of a spendthrift or that
of an altruist, it is a short-sighted policy. With our oil reserves so
plainly inadequate, it is not too much to treat our own country under a
kind of favored-nation policy. Surely the United States can rightfully
safeguard American interests at home and abroad, with the spirit of
reciprocity in trade relations.

OBTAINING A FUTURE SUPPLY

Two methods of handling the problem of a future oil supply suggest
themselves: either reserve the domestic oil fields for American develop-
ment and thus prevent foreign acquisition of what is needed at home-
or, encourage our capital to enter foreign fields to assist in their develop-
ment, thus insuring an additional supply of oil for our needs. The
one method harks back to the "Chinese wall" period, the other expresses
the "open door" policy. At present the United States Government
follows neither method; the British Government has adopted both.

The British Admiralty led the way in its appreciation of the advan-
tages of fuel oil, and the British Government has led the way in assuring
to its nationals control of oil resources wherever found on British terri-
tory. Advantages that American capital may once have held in Trinidad
and elsewhere in the British Empire are not now enjoyed and British
enterprise is narrowing the field of opportunity in Mexico, South America,
Mesopotamia, and Africa. Be it said, moreover, to the credit of British

DISCUSSION 93

efficiency and foresight, that British capital has made generous use of
American brains in discovering and developing its oil properties. Ameri-
can geologists, American engineers, American drillers, and American
rigs and supplies have been utilized in British oil exploration and we may
well reciprocate by adopting the British policy of encouraging the acqui-
sition by its nationals -of petroleum supplies in foreign fields. American
capital as well as American engineering should be encouraged to help
develop the new fields and so do its part in insuring the continuance
of this source of power for future generations at home and abroad.

The part of the Government is to give moral support to every effort
of American business to expand its circle of activity in oil production so
that it will be coextensive with the new field of American shipping.
This may mean world-wide exploration, development, and producing
companies, financed by United States capital, guided by American
engineering, and safeguarded in policy because protected by the United
States Government. 3 Thus only can our general welfare be promoted and
the future supply of oil be assured for the United States.

DISCUSSION

M. L. REQUA, New York, N. Y. (written discussion). This paper
calls attention to what is perhaps our most critical raw-material problem.
I have spoken and written so vigorously and frequently upon this sub-
ject that it seems almost useless repetition to refer again to the subject;
but, in the face of everything that has been said and done by various
individuals alive to the situation, we are utterly without any national
policy as related to foreign sources of petroleum supply. We build up
a great mercantile marine and predicate its success upon fuel oil, but
we make no really constructive effort to assure the source of supply for
that material. We construct warships made to burn nothing but fuel
oil, and we face a lack of preparedness and appreciation of the gravity of
the situation on the part of the directing head of the Navy that would
be grotesque were it not for the tragedy involved.

3 In his annual report to the President, the Secretary of the Interior states (pp.
18-20) that the present situation "calls for a policy prompt, determined, and look-
ing many years ahead." The supplemental supply needed "may be secured," he
says, " through American enterprise if we do these things: (1) Assure American
capital that if it goes into a foreign country and secures the right to drill for oil on
a legal and fair basis (all of which must be shown to the State Department) that
it will be protected against confiscation or discrimination. This should be a known
published policy. (2) Require every American corporation producing oil in a foreign
country to take out a Federal charter for such enterprise under which whatever oil
it produces should be subject to a preferential right on the part of this Government
to take all of its supply or a percentage thereof at any time on payment of the
market price. (3) Sell no oil to a vessel carrying a charter from any foreign govern-
ment either at an American port or at any American bunker when that government
does not sell oil at a non-discriminatory price to our vessels at its bunkers or ports."

94 A FOREIGN OIL SUPPLY FOR THE UNITED STATES

The day of reckoning must come, of course, in all things; and our
Government officials have before them a very unpleasant experience
when they have to explain the lack of foresight as regards petroleum.
The documents on file in various governmental departments in Washing-
ton calling attention to this situation would make, if assembled as a
whole, extremely interesting reading in the light of events. To my
knowledge, the Director of the Geological Survey has for at least five
years been urging proper consideration of the subject.

CHESTER W. WASHBURNE, New York, N. Y. (written discussion).
It is a delightful surprise to read Doctor Smith's statement that the policy
of withdrawing government oil lands ' ' may be regarded now as having
outlived both its intent and its usefulness." It has indeed become a
nuisance and an injustice to anyone who discovers oil on the public
domain, only to have the benefits of his intelligence and daring snatched
away by Presidential decree. Everyone, even the old-timers who
thought differently, now recognize that the oil supplies of this country are
wholly inadequate for our own future needs. The passage of a good leas-
ing bill will help a little; the development of foreign oil fields is the great
necessity.

Foreign development of any consequence requires two things. First,
there should be greater backbone in the American State Department and
President in protecting and helping American capital in foreign fields.
The recommendations of the Secretary of the Interior outlined by Doctor
Smith would help, if adopted. Secondly, there should be greater and
more persistent efforts of American capital in hazardous foreign under-
takings. The second element already shows manifestations of serious
importance. In the first we are outclassed by the well-knit organiza-
tion of the British Foreign Office and the harmoniously working British
Consular Service.

In view of the great risks involved and the high expenditures, it
would be wise for American companies to combine in some way for foreign
work. The principal American companies working in any one foreign
country should be able to pool their interests in some way, to avoid
bidding against each other for concessions, etc. One way in which this
could be done is exemplified by the British companies in Venezuela,
which operate independently in the field, each in its own area, but which
are in close, though more or less secret, association in London. They
practically have cornered the best part of Venezuela, while the American
companies remained uninterested. We soon will regret this oversight.
As an example of the way American companies work, I will cite one
experience. Several years ago, I had a distinguished oil geologist examine
certain properties in Colombia. He condemned them. Since then four
American companies successively have sent expeditions to examine the

DISCUSSION 95

same properties, and since no one has taken them I presume all geologists
have condemned them. The mouth of each geologist is sealed by pro-
fessional ethics, but the heads of the companies in question might have
been friendly enough to prevent this foolish reduplication. I believe
these properties will remain on the market for future examination, until
some company happens to send a poor geologist who will allow his
employers to pay a big bonus and drill some dry holes. Meanwhile
British capital has been strengthening its position in the more desirable
territory to the east, Venezuela.

Two American companies have been trying to get another Colombian
property that looks rather attractive, but their efforts have resulted
in boosting the price to a foolish figure. Development is delayed until
the owners will listen to reason. Cooperation would have saved this
situation. Cooperation would have resulted in definite development
in other foreign affairs where Americans have been competing with each
other.

R. H. JOHNSTON,* Washington, D. C. The remarks just made
emphasize the fact that Great Britain enjoys a much more vigorous
foreign policy than does this country. During the discussion regarding
the Persian oil fields, 4 the suggestion was made that American companies
should take part in the development of these fields. On Aug. 9, 1919,
Great Britain signed a treaty with Persia, from which I will read three
paragraphs:

(2) The British Government will supply, at the cost of the Persian Government,
the services of whatever expert advisers may, after consultation between the two
governments, be considered necessary for the several departments of the Persian
administration. These advisers shall be engaged on contracts and endowed with
adequate powers, the nature of which shall be the matter of agreement between the
Persian Government and the advisers.

(3) The British Government will supply, at the cost of the Persian Government,
such officers and such munitions and equipment of modern type as may be adjudged
necessary by a joint commission of military experts, British and Persian, which
shall assemble forthwith for the purpose of estimating the needs of Persia in respect
of the formation of a uniform force which the Persian Government proposes to
create for the establishment and preservation of order in the country and on its
frontiers.

(4) For the purpose of financing the reforms indicated in clauses two and three
of this agreement, the British Government offers to provide or arrange a substantial
loan for the Persian Government, for which adequate security shall be sought by the
two governments in consultation in the revenues of the customs or other sources of
income at the disposal of the Persian Government. Pending the completion of
negotiations for such a loan, the British Government will supply on account of it
such funds as may be necessary for initiating the said reforms.

* Vice President, The White Co. 4 See p. 16.

96 A FOREIGN OIL SUPPLY FOE THE UNITED STATES

So you see that the Persian oil fields are pretty well controlled by
Great Britain. Not only is Great Britain pursuing its historic policy
of making the lives and investments of British subjects safe in every
part of the world, but this treaty practically puts the administration of
Persia's affairs into the hands of British advisers. It would not be
desirable for the United States to make treaties of this kind, but the suc-
cessful development of foreign fields by American capital hinges entirely
upon our having a vigorous foreign policy.

PETROLEUM RESOURCES OF KANSAS 97

Petroleum Resources of Kansas

BY RAYMOND C. MOORE,* PH. D., LAWRENCE, KANS.

(New York Meeting, February, 1920)

THE oil-producing districts of Kansas comprise the northern portion
of the so-called Mid-Continent field. As shown in the accompanying
map, these districts are located chiefly in the southeastern and south
central parts of the state. A considerable area in southeastern Kansas,
extending northward nearly to Kansas City, has long been known as oil
territory, the productive wells being distributed in patches or spots of
irregular size and shape, the location of which is controlled by conditions
of rock structure, and by the texture and porosity of the "sands" beneath
the surface. In south central Kansas, there are a number of producing
fields, the location of which appears to be controlled chiefly by well-de-
fined structure. The most important districts are those in Butler County,
especially that in the vicinity of El Dorado, which was for a time the most
productive district in the entire Mid-Continent field. Recently new pro-
duction of importance has been brought in the vicinity of Peabody and
present development is active to the north across Marion County. Tests
in the western parts of Kansas have not been successful in finding new
petroleum fields.

HISTORY

The first well drilled for petroleum, in Kansas, was near the town of
Paola, Miami Co., about 40 mi. southwest of Kansas City, in the summer
of 1860, only a few months after the completion of the famous "Colonel"
Drake discovery well in Pennsylvania. Kansas appears to be the second
state to engage in a serious attempt to find oil by drilling. The Civil
War caused the temporary abandonment of attempts at oil development
in the state.

It was in the vicinity of Paola, where numerous oil seepages had been
observed, that the first well producing oil in commercial quantities was
drilled, 1 where also gas was first piped to the city for commercial use.
Prospecting spread southward into Linn County and northward into

* State Geologist of Kansas.

1 Raymond C. Moore and Winthrop P. Haynes : Oil and Gas Resources of Kansas.
Kans. Geol. Survey Bull 3a (1917) 20.
voi,. ijcv. 7

PETROLEUM RESOURCES OF KANSAS

Johnson and Wyandotte Counties, a number of small gas wells being ob-
tained. Later development extended southward toward lola, Chanute,
Neodesha and Coffeyville, reaching to the boundary of the Indian Terri-

Ixxjation Map of
-CONTrNENT FIELD

AFTER DAVIO T. DAY

Scale 1: 5,OOO.OOO

FlG. 1.

tory, now Oklahoma. From 1891 until 1894, prospectors covered the
entire southeastern part of Kansas along the Neosho and Verdigris rivers.
Many oil wells, though none with very large individual production, were

RAYMOND C. MOORE 99

brought in, particularly in Allen, Neosho, Montgomery, and Wilson
Counties.

The production of petroleum in Kansas amounted to relatively little
until tests completed in the then Indian Territory showed that beneath the
Mid-Continent plains lay really important deposits of oil. The great
impetus then given to drilling in Kansas resulted in a very rapid increase
in the volume of production. Although in 1900 less than 75,000 bbl. of
oil were obtained in the entire state, the production in 1904 amounted to
4,250,779 bbl. Due to the decline in price, drilling fell off and so large
an annual production was not again reached until 1916 when, with a
considerably increased market price and the recent discovery of the rich
Butler County fields, the production of the state was brought to nearly
9,000,000 barrels.

The larger place which Kansas has occupied in recent years as a pro-
ducer of petroleum is almost wholly due to the discovery in June, 1914,
of commercial quantities of oil in Butler County, south central Kansas.
It has been known for a number of years that gas was available in this
part of the state. One of the wells in the Augusta gas district was drilled
into an oil sand at a depth of about 2500 ft. (761 m.) and before the end of

1914 five oil wells had been drilled in the heart of the gas field. By the
close of 1915, the number of oil wells was increased to twelve, one of
which is reported to have had an initial natural flow of 1500 bbl. Mean-
while, geological examination of the country to the north revealed a very
promising structure in the vicinity of El Dorado. In the latter part of

1915 the Continental Oil & Gas Co., now the Empire Gas & Fuel Co.,
brought in a 100-bbl. well on the Stapleton farm, section 29, township 25
south, range 5 east, about 15 mi. northwest of Augusta. The discovery
was in a sand penetrated at a depth of about 660 ft. (198 m.) Offset wells
confirmed the importance of the shallow sand but in the first well the sand
was cased off and the drilling continued. A lower productive sand was
encountered at a reported depth of 2460 ft., the well being completed with
an initial production of 120 bbl. a day from this horizon. Succeeding
wells were, for a time, drilled into the shallow sand only. Later the
deeper sands were developed, culminating in the disco very and exploitation
of the 2500-ft. sand in the Towanda district in the spring and summer of
1917, Some of the wells in this district are reported to have had an
initial daily production of more than 25,000 barrels.

In the latter part of 1918, oil was discovered in the extreme north-
western part of Butler County east of Elbing. The wells were not im-
portant, but the drilling in the early part of 1919 on a favorable structure
south of Peabody, Marion Co., was marked by large production. The
present activity in development is in this region and northward across
Marion County into Dickinson County.

100 PETROLEUM RESOURCES OF KANSAS

STRATIGRAPHY

In general, the geology of Kansas is almost ideally simple. The state is
a typical part of the Great Plains region and has the uniformly gentle slope
and simplicity of geologic structure which characterize the plains. The
surface of Kansas has a general inclination from west to east amounting
to about 10 ft. (3 m.) per mile, the elevation of the western state boundary
being about 3500 to 4000 ft., that of the eastern boundary from 750 to
1000 ft. The rock formations of which this sloping plain is built lie
almost flat and are exposed in broad north-and-south bands across
the state. They sag slightly in central Kansas, the rock slope, or
dip, being toward the west in the eastern counties and to the east in the
western part of the state. The oldest beds appear at the surface in the
east and dip beneath the younger overlying formations, which appear in
succession as the state is crossed to the west.

The rocks in the general region of the Mid-Continent field range in
geologic age from almost the oldest known to the youngest. The oldest
rocks are granites and other crystalline rocks of pre-Cambrian age, which
are exposed in the southeastern part of Missouri, in the Ar buckle and
Wichita Mountains of Oklahoma, in the Rocky Mountains of Colorado,
and at points north of Kansas farther distant. The pre-Cambrian no-
where appears at the surface in Kansas, but recent exploration for oil
and gas in the central part of the state suggests that it approaches
the surface much more closely than was supposed. Sufficient tests have
been made to indicate quite clearly the presence of a buried ridge or
mountain range of granite, which appears to trend in a direction slightly
east of north from Butler County to the northern limits of the state.
No evidence of metamorphism of the sedimentary rocks immediately
overlying the granite has been found, and it is probable that the ridge
represents a part of the pre-Cambrian floor.

Table 1 presents the chief stratigraphic divisions of the rocks of
Kansas.

Strata which belong to the Cambrian and Ordovician, consisting of
dolomites, limestones, shales, and sandstones, and aggregating about
2000 ft. (609 m.) in thickness, underlie eastern Kansas and perhaps other
parts of the state. They have been penetrated in a number of wells but
in no place found to contain commercial quantities of petroleum or natural
gas. Upon the eroded surface of the rocks of the older Paleozoic, in the
Great Plains country, is found the Mississippian system, or, as it is called
by drillers, the "Mississippi lime." The Mississippian is a clearly
defined, readily traceable, stratigraphic unit, consisting chiefly of
crystalline limestones containing a rather unusual amount of hard
flinty chert.

RAYMOND C. MOORE

TABLE 1. Geologic Section of the Kansas Region

101

System

Groups

Formation

Character of Rocks

Cenozoic

Quaternary

Recent

Alluvium, dune sands

Pleistocene

Wisconsin stage
Kansas stage

Glacial deposits

Tertiary

Pliocene
Miocene

Ogalalla

Gravel, sand, clay

Mesozoic

Cretaceous

Montana

Pierre

Shale

Colorado

Niobrara
Benton

Limestone, chalk, shale

Dakota

sandstone

Sandstone, shale

Comanchean

Washita

Kiowa
Cheyenne

Sandstone, shale

Ins
Not exposed in Kansas ,
2

zoic

Permian

Cimarron

Greer
Woodward
Cave Creek
Enid

"Red beds," sandstone,
shale, dolomite, gyp-
sum, salt

Big Blue

Wellington
Marion
Chase
Council Grove

Shale, limestone

Pennsylvanian

Missouri

Wabaunsee
Shawnee
Douglas
Lansing
Kansas City

Limestone, shale, sand-
stone

Des Moines

Marmaton
Cherokee

Limestone, shale, sand-
stone

Mississippian

Unconformity
Ordovician

Chester
Unconformity

Osage

Warsaw
Keokuk
Burlington
Pierson

Limestone

Pre-Cambrian

Kinderhook

Limestone, shale

Joachim
Jefferson City
Roubidoux

Dolomite, sandstone,
shale

Cambrian

Gasconade
Proctor
Eminence
Potosi

102 PETROLEUM RESOURCES OF KANSAS

TABLE 2. Divisions of Pennsylvanian Rocks of Kansas

Group

Formation

Member

Thickness,
Feet

Eskridge shale

30-40

Neva limestone

3-5

Elm dale shale

120-140

Wabaunsee formation

Americus limestone

6-10

Admire shale 1

276-325

Emporia limestone

5-10

Willard shale

45-55

Burlingame limestone

7-12

Scranton shale

160-200

Howard limestone

3-7

Severy shale

40-60

Topeka limestone

20-25

Shawnee formation

Calhoun shale

0-50

Deer Creek limestone

20-30

Tecumseh shale

40-70

Lecompton limestone

15-30

Kanwaka shale

50-100

Missouri

Oread limestone

50-70

Lawrence shale*

150-300

Douglas formation

latan limestone

3-15

Weston shale

60-100

Stanton limestone

20-40

Vilas shale

5-125

Lansing formation

Plattsburg limestone

5-80

Lane shale

50-150

lola limestone

2-40

Chanute shale

25-100

Drum limestone

0-80

Cherryvale shale*

25-125

Kansas City formation

Winterset limestone

30-40

Galesburg shale

10-60

Bethany Falls limestone

4-25

Ladore shale

3-50

Hertha lime&tone

10-20

Pleasanton shale

100-150

Coffeyville limestone

8-10

shale

60-80

Marmaton formation

Altamont limestone

3-10

Des Moines

Bandera shale

60-120

Pawnee limestone

40-50

Labette shale

0-60

Fort Scott limestone

20-40

Cherokee shale 4

Undifferentiated

400-500

1 Possibly contains shallow oil sand at El Dorado.

* Includes Chautauqua sandstone member; probably 1500-ft. sand at Augusta and El Dorado.

* Possibly horizon of oil sand at 2400 ft. at Augusta and El Dorado.

* Includes the main oil sand outside Augusta and El Dorado and Peru; contains Bartlesville and
Burgess sands.

RAYMOND C. MOORE 103

In Oklahoma and northern Arkansas, it includes important beds of shale
and some sandstone; but where encountered by the drill in Kansas and
throughout most of Missouri, it is essentially a limestone series. An
exception, apparently, is found in central Kansas, according to recent in-
formation from well records, which indicate a disappearance locally of
the limestone and a replacement by clastic material. The thickness of
the system in the south central part of the Mississippi basin is more than
2000 ft., but in Kansas it is not more than 300 or 350 ft.

The oil and gas deposits of the Mid-Continent field are confined almost
wholly to rocks of the Pennsylvanian system, which outcrop in a broad
belt across eastern Kansas and Oklahoma. The rocks of this system
consist of a thick series of alternating shale and limestone formations,
with irregular beds of sandstone and some beds of coal. Though not
great in thickness, many of the beds are surprisingly persistent hori-
zontally, having been traced in most cases some hundreds of miles along
the outcrop. They have a total thickness of nearly 3500 ft. in the south-
ern part of the state and a slightly smaller amount to the north. A total
thickness of about 3000 ft. has been measured along Kansas River.

Table 2 shows the stratigraphic divisions of the Pennsylvanian that
have been recognized in Kansas, with their approximate thicknesses.

Permian rocks are found in a north- and- south band across central
Kansas. The zone of outcrop is narrow at the north, where it is over-
lapped from the west by the much younger beds of Cretaceous age, and
reaches its maximum width near the southern border of the state. The
lower Permian beds are marine and overlie the upper Pennsylvanian strata
without unconformity or other prominent mark of stratigraphic division.
The upper Permian, which is confined to the southwestern part of the
Permian area in the state, consists chiefly of red beds. The subdivisions
which have been made are listed in Table 3, with approximate thickness.

The remainder of the surface in Kansas is occupied by rocks of Cre-
taceous and Tertiary age. The former consists of an important basal
division of sandstone, the Dakota, and of middle and upper divisions of
chalky limestone and shale. The total thickness is approximately 1300
ft. Seepages of oil have been reported in the Cretaceous area and there
are some excellent structures, but no commercial production of oil has
been obtained from these rocks or in the part of the state in which they
outcrop.

In common with the Mississippian and older systems that underlie it,
the Pennsylvanian strata have a gentle inclination outward from the
Ozark highland. In northeastern Kansas, they dip toward the north-
west; in central eastern Kansas, almost due west; and in the southern
counties, slightly southwest. If the Pennsylvanian is continuous be-
neath the thick overlying formations of Permian, Cretaceous, and Ter-
tiary age in the western part of Kansas, the system is a part of the broad

104 PETBOLEUM RESOURCES OF KANSAS

TABLE 3. Subdivisions of Permian System in Kansas

Group

Formation

Member

Thickness,
Feet

Greer

Big Basin sandstone

shale

Day Creek dolomite

1-5

Woodward

Whitehorse sandstone

175-200

Dog Creek shale

Cimmaron

Shimer gypsum

4-25

Cave Creek

Jenkins shale

5-50

Medicine Lodge gypsum

2-30

Flowerpot shale

150

Enid

Cedar Hills sandstone

50-60

Salt Plain shale

155

Harper sandstone

350

Wellington

Undifferentiated

500-800

Abilene limestone

4-8

Pearl shale

Marion

Herington limestone

12-15

Enterprise shale

35^4

Luta limestone

Big Blue

Winfield limestone

20-25

Doyle shale

Chase

Fort Riley limestone

40-45

Florence flint

Matfield shale

60-70

Wreford limestone

35-50

Council Grove

Garrison shale and limestone

135-150

Cottonwood limestone

shallow sag, or syncline, that characterizes the general structure of the
state. However, when examined in detail it is seen that there are many
irregularities in^the structure of the Pennsylvanian rocks. In many
places in eastern Kansas, the rock strata are absolutely horizontal,
and in a number of places, they are inclined to the east for short dis-
tances. These irregularities are minor waves on the major structure
of the Pennsylvanian but are, in most instances, the controlling feature
in the accumulation of commercial deposits of oil. Most of the minor
structures are of the unsymmetrical dome type, the rocks dipping away
in all directions. Others are merely terraces, or "noses, " where the
western dip is diminished sufficiently to permit local accumulation of
petroleum. None of the structures are very prominent, the vertical

RAYMOND C. MOORE

105

distance from the top of one of the best defined anticlines to the upper
part of the adjacent saddle, that is the closure, being only 160 feet.

The texture of the "sand" is a controlling factor in the production
of areas in southeastern Kansas. Oil and gas wells with an important
production are located in many instances without relation to structure,
the supply of oil and gas being controlled by the lenticular character
or the "patchy" texture of the sands.

TECHNOLOGY

Two types of drilling are employed in the Kansas fields, the standard,
or cable drilling, which is used in all the deeper wells, and the Star, or
Parkersburg type, which is commonly used in the shallow fields of the
eastern part of the state.

On account of water conditions in certain parts of the Kansas fields,
especially in the El Dorado and Augusta districts, the depth to which the
oil-producing sand is penetrated and the casing of the well are important
considerations. If the well is drilled too deep, there is danger of drowning
within a comparatively short time. In most cases, only the ordinary
requirements of casing are met. The use of cement and the mud-
laden fluid has been successful, where employed in the Butler County
wells, but there has been no uniformity of practice, due to varying condi-
tions in the field and to lack of state supervision.

PRODUCTION STATISTICS

Most of the wells in the Kansas fields are not large producers, the
average yield amounting to but a few barrels a day. The largest pro-
duction from individual wells has been found in the El Dorado-Towanda
district, where at least one well is reported to have flowed more than
25,000 bbl. a day. The initial production of many wells in this part of
the state has exceeded 2000 bbl. a day. Table 4 shows the average pro-
duction of oil wells in Kansas from 1910 to 1918 based on available data.

TABLE 4. Average Production of Oil Wells in Kansas, 1910-1918

Year

Total Produc-
tion, Barrels

Total Number,
Oil Wells

Dry Holes

Average Annual
Production per
Well, Barrels

Average Daily
Production per
Well, Barrels

1910

1,128,668

1,831

616

1.7

1911

1,278,819

1,787

715

1.9

1912

1,592,796

1,757

906

2.5

1913

2,375,029

1,812

1,310

3.5

1914

3,103,585

3,054

156

1,016

2.8

1915

2,823,487

3,460

158

810

2.2

1916

8,738,077

3,673

360

2,379

6.5

1917

36,536,125

5,843

420

6,253

17.1

1918

43,253,470

8,950

925

4,833

13.2

106 PETROLEUM RESOURCES OF KANSAS

The crude petroleum has a specific gravity ranging from about 20
Baume*, for some of the southeastern oils, to 40 or slightly higher for
some of the oils in the Butler County district. The specific gravity of the
oil in the vicinity of Chanute, Coffeyville, and Independence is about
30 to 32. This heavy oil has considerably less gasoline than the oils
with higher specific gravity. On account of this there has been a tendency
for some of the refineries to move to points from which a larger supply of
higher grade oil could readily be obtained.

The oil is gathered by pipe lines from the producing fields in the Butler
County district and from other important areas, pipe lines converging
toward the northeast in the vicinity of Kansas City. A considerable
number of tank cars are used both in the transportation of crude oil
from some of the fields and in the distribution of the refined product.

According to the best available records, Kansas had produced to the
end of the year 1918 a grand total of 119,898,233 bbl. of crude oil. The
character of the Kansas oil fields is in part indicated by the statistics of
wells drilled. Throughout the larger part of the producing area, especially
that located in the southeastern counties of the state, the wells are num-
erous, but none have a large output. The average yield for each producing
well is from 1 or 2 to 25 bbl. a day. In the Butler County fields, some of
the wells were credited with a very large individual daily output. In
general, the interest in development and activity in the fields is also shown
by the number of new wells drilled. Field operations follow more or
less closely the fluctuation of the market, periods of greatest activity ac-
companying times of highest crude-oil prices. In the years 1912 to 1918,
inclusive, 13.649 wells were drilled, of which 10,979 were producing and
2670 dry. Of the 4671 wells put down in 1918, 2549 were oil producing
and 272 gas wells.

FUTURE POSSIBILITIES

At the present writing, the rich Butler County fields are past the
zenith of their production, the climax having been reached with the de-
velopment of the Towanda district, which reached its peak in 1918.
The discovery of new fields, east of Elbing and extending toward Peabody,
in Marion County, has given new impetus to development in this part
of the state. Tests south of the El Dorado and Augusta fields, toward
the Blackwell area, have thus far given little encouragement, but satis-
factory showings in structures located in Marion County and northward
into Dickinson County are attracting considerable attention.

Southeastern Kansas fields have been thoroughly tested and, with the
exception of new wells in porous sands that have not yet been drained,
there is little additional production to be expected. It is possible that
new pools will be discovered in part of the state between the old oil and

RAYMOND C. MOORE 107

gas fields in the vicinity of Chanute, lola, and Independence, and the
fields farther west, Butler County and trending toward the north. De-
velopment in this area, however, cannot be foreseen.

In summary, the Kansas oil fields are, in all probability, beyond the
zenith of their production. Much of central and western Kansas may
yet be tested, but conditions are difficult or impossible to predict, and the
result cannot be foreseen.

108 RISE AND DECLINE IN PRODUCTION OF PETROLEUM

Rise and Decline in Production of Petroleum in Ohio and

Indiana

BY J. A. BOWNOCKER,* D. Sc., COLUMBUS, OHIO
(New York Meeting, February, 1920)

THE existence of petroleum in the rocks of Ohio and Indiana seems
to have been first shown by wells dug for salt. The fuel, however, was
objectionable owing to its odor and inflammability. Not until the Drake
well was drilled in 1859 did the people appreciate the value of rock oil, and
then they at once began plans to secure the coveted fuel. The first
successful well in these two states was near Macksburg, in southeast
Ohio, where at a depth of 59 ft. (17 m.) oil was found in commercial
quantity (1860). A year later this fuel was secured on Cow Run, in the
same county, and at about the same time in Noble, Morgan and perhaps
other counties in that part of Ohio.

The second great step in the production of oil in Ohio and Indiana was
taken in 1884 when the reservoir of natural gas in the Trenton limestone of
northwest Ohio was tapped, and where a year later oil was secured in the
same formation. Petroleum in this limestone was obtained in Indiana
in 1889. l

The third step in the production of oil in Ohio and Indiana is associa-
ted with the Clinton sand of Ohio. Natural gas in large volume was dis-
covered in that rock at Lancaster, in 1887, and the area has been extended
until it has become the largest individual producer in the world. The
presence of natural gas in such great volume all but demonstrated to the
driller that oil lay hidden near by. Soon the search for it was started but
not until 1899 was petroleum in commercial quantity found in the Clinton
sand, and a large pool was not located in it until 1907.

The fourth step in the development of the industry was taken in 1913,
when the pool in Sullivan County, in western Indiana, was opened. The
producing rock is the Huron sandstone, which is the topmost member of
the Mississippian system. 2

* State Geologist and Professor of Geology, Ohio State University.

1 Dept. of Geol. and Nat. Res. of Indiana, 2Sth Ann. Rep. (1903) 82.

* Edward Barrett: Dept. Geol. and Nat. Res. of Indiana, ZSth Ann. Rep. (1913)
9-34.

J. A. BOWNOCKER

109

TABLE 1. Production in Ohio and Indiana

1876.
1885.
1889.
1896.
1904.
1914.
1918.

OHIO,
BARRELS

31,763

661,580

12,471,466

23,941,169

18,876,631

8,536,352

7,285,005

INDIANA,
BARRELS

33,375

4,680,732

11,339,124'

1,335,456

877,588

TOTAL
BARRELS

31,763

661,580

12,504,841

28,621,901

30,215,755*

9,871,808

8,162,563

Maximum production for state.

6 Maximum production for the two states combined.

PRODUCTION FROM THE TRENTON LIMESTONE IN OHIO AND INDIANA

When natural gas was discovered in the Trenton limestone at Findlay,
Ohio, in 1884, and petroleum a year later, it marked an epoch in the
geology of petroleum. Heretofore the source of these fuels had been in
sandstones or conglomerates, and limestones were regarded as non-
petroliferous. For this reason the new field was looked on by the prac-
tical oil man with much suspicion, which was increased when he noted
the dark color and bad smell of the oil. It was soon found, too, that the
methods of refining hitherto practiced would not apply, which, of course,

PRINCIPAL PRODUCING OIL ROCKS IN OHIO AND INDIANA

Pennsylvanian

Mississippian

Mitchell sand (Ohio)

First Cow Run or Macksburg 140-ft. sand (Ohio)

Macksburg 500-ft. sand (Ohio)

Macksburg 800-ft. sand (Ohio)

Huron sand (Indiana)
Keener sand (Ohio)
Big Injun sand (Ohio)
Berea sand (Ohio)

Devonian Cornif erous limestone (Indiana)

Silurian Clinton sand (Ohio)

Ordovician Trenton limestone (Ohio and Indiana)

was another objection to the fuel. However, the oil had a market,
which insured further drilling. Wells were completed as fast as the tools
could be forced through the rocks and the production of oil increased
at a rapid rate. In fact, the supply grew faster than the demand so that
the storage of the fuel became a serious problem. To check production,
the Standard Oil Co. reduced the price time and again until, in July,
1887, it was listed at only 15 cents per barrel. In spite of this, drilling
continued and the production kept apace. The development of an
improved method of refining strengthened the market for the crude oil

110

RISE AND DECLINE IN PRODUCTION OF PETROLEUM

and the price advanced, with some fluctuations, until at present (Octo-
ber, 1919) it is $2.48 per barrel.

While the Lima-Indiana field was opened 34 years ago, drilling has
been continuous and is still in progress. In 1917, 534 wells, of which 174
were producers, were drilled in Ohio and 266, of which 174 were producers,
were completed in Indiana. The magnitude of the drilling is well shown

UJ
CC

t/5

z
o
=5

I
z

2T 10
o

o
g 5

m i> r~ co o o
oo of

oo oo

coo> o ruro^iovol"-coc>o cu co ^ LO vO r^ (0
o ~~ --- ---

O o O) <

YEARS
FIG. 1.

by the fact that from June, 1905, to Dec. 31, 1917, 12,514 wells were sunk
in the Ohio part of the field and 15,005 on the Indiana side. 8 Barrett
estimates that 30,000 wells have been drilled to the Trenton in Indiana
and the number in Ohio must have been larger because the producing
area is much greater.

With Findlay as a center, drilling was carried on in all directions,
but it was soon learned that the producing territory had narrow
limits along an east-and-west line and that it was continuous in a

Petroleum in 1917. U. S. Geol. Survey Mineral Resources (1919) 750.

J. A. BOWNOCKER 111

northeast-southwest direction. By 1890, the field had been pretty
definitely delimited and was found to form an arc of a circle from the
western end of Lake Erie southwest through Wood, Hancock, Allen,
Auglaize, and Mercer Counties to the Indiana line, which it later crossed
and extended slightly northwest to near Marion, Grant Co. The total
length of the field is about 150 miles (241 km.) but the width varies
greatly; in places it is only a fraction of a mile while elsewhere it may have
a width of 20 miles.

The maximum production from the Trenton limestone of Ohio
was reached in 1896; it was 20,575,138 bbl. The Indiana part of
the field, as it was developed later, did not attain its maximum until 1904,
when it produced 11,317,259 bbl. Fig. 1 shows the rise and decline of
the entire field.

The size of the wells varied greatly but the maximum seldom reached
10,000 bbl. Initial productions of from 100 to 500 bbl. per well, however,
were common, and the shallowness of the wells made them profitable
though the price of oil was low. Everywhere salt water was found, and
the work of pumping this has been enormous. Streams were made
brackish and the water therefore unfit for use. The oil has a density of
from 36 to 42 Be*., and is consequently heavier than the Pennsylvania
oil. Its base is chiefly paraffin, though some asphalt is present. Sulfur
is an objectionable constituent. The oil is darker than the Pennsyl-
vania product and the odor more disagreeable.

Because of its thickness and continuity, the Trenton limestone may
be thought of as the rock floor of both Ohio and Indiana. It rises to
the surface in only one locality the Ohio Valley from Coney Island (near
Cincinnati) to Ripley, Brown County. From this locality it dips to
the east, north, and west, but rises to the south and forms the surface
rock in part of the blue-grass region of Kentucky. At Findlay, it lies
1092 ft. (332 m.) below the surface; at Columbus, 2035 ft.; and at
Cleveland, 4445 ft. In Indiana similar, though not as large, variations
are found. Everywhere in both states, outside of the narrow area of
outcrop located above, the Trenton has always been found if the drill has
penetrated to its horizon.

In thickness, the Trenton shows much variation, but using the name in
its older and broader sense the rock is everywhere measured by hundreds
rather than by tens or scores of feet. Thus, at Findlay its thickness is
729 ft. (222 m.) 4 ; at Columbus, 475 ft.; 5 and at Waverly, in southern
Ohio, 808 ft. 6

The composition of the Trenton limestone varies both horizontally

<D. D. Condit: Am. Jnl. Sci. (1913) 36, 125.

'Edward Orton: Geol. Survey of Ohio (1888) 6, 107.

J. A. Bownocker: Geol. Survey of Ohio Bull. 12 [4] (1910) 48.

112 RISE AND DECLINE IN PRODUCTION OF PETROLEUM

and vertically. Where the rock yields oil or gas in commercial quantity,
it is magnesian, as is shown by the following analyses :

CaCOi MgCO INSOL. RESIDUE AljOs AND Fe 2 O

Findlay, Ohio 53.50 43.05 1.70 1.25

Bowling Green, Ohio 51 . 78 36 . 80 4 . 89

Lima,Ohio 55.90 38.85 0.75 2.94

Kokomo, Indiana 52.80 39.50 4.60 2.40

In places, at least, the Trenton changes rapidly with depth. Thus,
at Bowling Green an analysis of the rock from 100 ft. (30 m.) below its
top showed more than 88 per cent, of calcium carbonate and less than 7 per
cent . of magnesium carbonate, while the top beds gave less than 42 per cent .
of calcium carbonate and nearly 37 per cent, of magnesium carbonate.
Outside of the producing territory, the Trenton appears to lose its mag-
nesian character, for the calcium carbonate rises in most places to at
least 75 per cent, of the rock. 7 Since there is an increase in porosity with
magnesium carbonate, the composition of the rock may have much to do
with its capacity to store the oil.

The color of the Trenton limestone is dark gray, judging from pieces
thrown to the surface when the wells are torpedoed. It is finely crystalline
and contains numerous veins of dolomite. Cavities, doubtless the work of
solution, are common and greatly increase the storage capacity of the rock.

The depth of wells usually ranges from 1000 to 1500 f t. (304 to 457 m.) in
Ohio; in Indiana the depth averages about 1000ft. The great body of the
oil is in the upper 50 ft. of the reservoir rock, but a second and even a
deeper pay has been found in places ; these, however, have yielded but
little oil. Efforts have been made to find oil in rocks below the Trenton,
but without success. In a well drilled near Findlay, Ohio, in 1912,
work did not cease until the tools had penetrated the rocks to a depth of
2980 ft.; granite or a similar rock was struck at 2770 ft.

The thickness and structure of the rocks are remarkably uniform, and
while there is considerable variation in depth of wells, it results almost
wholly from the anticlinal structure. Naturally, wells located on the
top of the arch are the most shallow. Following are representative well
records from Ohio and Indiana:

TABLE 2. RECORDS OF OHIO AND INDIANA WELLS

OHIO INDIANA

THICKNESS, THICKNESS,

FEET FEET

Drift 43 Drift 50

Monroe limestone 107 Niagara limestone 153

Niagara limestone 140 Cincinnati shales 751

Niagara shale 13 Trenton limestone at 954

Brassfield limestone 89

Gray shale 47

Red shale 45

Cincinnati shales 706

Trenton limestone at 1 190

' Edward Orton: Geol. Survey of Ohio (1888) 6, 103-104.

J. A. BOWNOCKER 113

The petroleum in the Lima-Indiana field is, in places at any rate,
closely related to structure. As is well known, the Cincinnati axis, a
broad fold, crosses the Ohio River about 25 miles east of Cincinnati and,
extending west of north for perhaps 40 miles, bifurcates, one arm running
a few degrees east of north toward the western end of Lake Erie and the
other arm west of north toward the southern end of Lake Michigan. In
Lucas, Wood, Seneca, and Hancock Counties, Ohio, the principal oil
fields are on the summit or eastern slope of this arch. Farther southwest,
in Allen, Mercer, and Auglaize Counties, Ohio, the productive territory
is on the west side of the arch, while in Indiana it is on the north side.
The Ohio part of the field was one of the first to lend support to, if not
to demonstrate, the anticlinal theory that has recently been announced
by I. C. White.

The Lima-Indiana field passed its zenith nearly a quarter of a century
ago. It is still an important producer but is steadily decreasing. While
new wells are completed by the hundreds each year, these by no means
equal the number of old wells abandoned. Manifestly this field cannot
be relied on to meet the present, much less the rapidly growing, demand
for petroleum.

PRODUCTION FROM THE CLINTON SAND FIELDS IN OHIO
The Clinton sand nowhere outcrops in Ohio; hence our knowledge of
it has been obtained entirely from the drill. The rock was first struck at
Lancaster, in 1887, and was considered limestone, but this error was soon
corrected. While still called Clinton, it has been pretty definitely shown
that the rock forms a part of the underlying formation, the Medina. 8
The drill has demonstrated that the Clinton sand does not underlie the
western half of the state and that its place is there occupied by shales.
Since the rocks in eastern Ohio dip to the southeast, the horizon of
the Clinton sand is found at increasing depths as the Ohio River is
approached. Its position at Wheeling is about 6560 ft. (1999 m.) below
the Ohio Valley, though the drill has not penetrated to so great a depth
at that place. While it is probable that the Clinton sand underlies
eastern Ohio, its presence has not been demonstrated in the counties east
of Tuscarawas, Muskingum, Athens, and Gallia. Natural gas is now
secured in this sand in Tuscarawas County at a depth of nearly 4000 ft.,
which is the deepest source of either oil or gas in Ohio.

The Clinton sand is usually light colored and clean, but in places it is
brick-red. The range in thickness is generally from 10 to 40 ft. (3 to
12 m,) but the maximum occasionally reaches 100 ft. Along its western
edge, the sand is thinner and somewhat patchy. According to the tes-
timony of drillers, the sand is free from water when first penetrated,
making the territory unique among the oil fields of Ohio.

8 J. A. Bownocker: Econ. Geol (1911) 6, 37.

114

RISE AND DECLINE IN PRODUCTION OF PETROLEUM

Petroleum is now secured in the Clinton sand of Ohio in Hocking,
Perry, Fairfield, Muskingum, and Wayne Counties and, to a very small
extent, in several others. The pools, however, are nearly all small, the
largest being in Perry County. The oil has a density of from 35 to 46
Be" and much of it is of Pennsylvania grade. Few wells have had an
initial production as large as 1000 bbl. per day; in fact, those starting at
as much as 500 bbl. have been rare. The production, however, is well
maintained, which helps compensate the operator for his great labor and
expense. The maximum production of the sand was about 1,300,000
bbl. per year, but it is now smaller. Much time and money have been
expended in an effort to extend the producing territory to the east, but the
results have been unsuccessful.

The depth of wells varies with surface altitude and with dip. Near
Pleasantville, Fairfield County, the depth to the producing sand is about
2325 ft., while near Crooksville, in the eastern part of Perry County, the
depth is more than 3400 ft. These two wells represent very well the
present extremes for oil production from this sand in Ohio.

The position of the Clinton sand is usually from 100 to 150 ft. (30
to 45 m.) below the Silurian limestone, or "Big lime" as the rock is
known by the driller, and hence it is very easy for him to determine his
position with reference to the desired sand. The following well records,
one in southern and the other in northern Ohio, show very well the rock
succession:

Perry (

bounty

Wayne

County

Thickness,
Feet

To Bottom,
Feet

Thickness,
Feet

To Bottom,
Feet

Mantle rock

Big Injun sand.

100

235

Berea sand

718

495

Bedford and Ohio shales

1032

1750

1335

1830

Devonian and Silurian lime-
stones

798

2548

1085

2915

Clinton sand

2708

3135

The Bedford and Ohio shales form a great wedge-shaped mass with
the apex in central Ohio and the base near Wheeling, W. Va., where its
thickness is at least 2500 ft. The Devonian and Silurian limestones
increase in thickness to both the east and the north. At Columbus
they measure 770 ft.; at Zanesville, 1012 ft.; and at Wheeling, 1900 ft.
To the northeast, the thickness increases from 770 ft. at Columbus to
1085 ft. in Wayne County, and reaches a maximum of 1400 ft. at Cleve-
land. It is the increasing thicknesses of these rocks that give the under-
lying Clinton sand its sharp dip, hence its rapidly increasing depth.

J. A. BOWNOCKEK 115

The structure of this sand, in its broader aspect at any rate, is easily
stated. It dips to the southeast, while in the longitude of Columbus it
thins and is replaced by shales. It may, therefore, be compared with
one arm of an anticline. Along the western, or higher, part of this arm,
great volumes of natural gas have been found; while a little farther east,
and hence at a lower level, reservoirs of oil have been located. How the
oil got into its position is not clear, for the absence or scarcity of water
deprives us of the usual agent. Neither is it plain how the oil is held in
its present location, but possibly it rests in shallow basins.

PRODUCTION FROM THE CORNIFEROUS LIMESTONE OF INDIANA
The Corniferous limestone that forms the base of the Devonian in
Ohio and Indiana is a source of petroleum in the latter state, but not in
the former. However, even in Indiana, the reputation of this rock as a
source of fuel rests on a single well, the Phoenix, which was drilled in
Terre Haute in 1889 and is credited with being the best payer ever
drilled in the state. 9 The limestone was struck at a depth of 1660 ft. and
for at least 12 years the production averaged 1000 bbl. of oil per month.
In 1908, it averaged 340 bbl. per month; few wells in this country have
so large a daily yield after 30 years continuous production. l Later, a few
small wells were secured in the same formation south and southeast of
Terre Haute, but were it not for the remarkable Phoenix well, the terri-
tory would not be mentioned.

PRODUCTION FROM MISSISSIPPIAN AND PENNSYLVANIAN SANDSTONES

IN OHIO AND INDIANA

Since these producing rocks have similar physical and chemical proper-
ties and representatives of both groups may be yielding oil in the same
territory, they will be reviewed together. Next to the Trenton lime-
stone, they have been the largest producers of oil in each state, and at the
present time they are the largest source in Ohio.

The producing territory in Ohio is restricted to the eastern half , since
that is the only part where rocks of this age are present. Trumbull and
Lorain have been the northernmost counties, though neither was ever a
large producer. The large sources of oil, now as in the past, are Jefferson,
Harrison, Belmont, Monroe, Noble, Washington, Morgan, and Perry
Counties, with Monroe and Washington far in the lead. As previously
stated, drilling in this territory started in 1860 and is still in progress.
In 1891, oil in the deeper sands of Monroe County was first secured and
that marked the beginning of the large source of oil in eastern Ohio.
Most of the pools are small, but some of these in Monroe and Washing-
ton Counties compare favorably in size with the largest of the Appa-

W. S. Blatchley: Dept. of Geol. and Nat. Res. of Indiana, 25th Ann. Rep. (1900)
517. Also 33rd Ann. Rept. (1908) 373.

10 This well is still producing between 3000 and 3500 bbl. per year.

116

RISE AND DECLINE IN PRODUCTION OF PETROLEUM

Fbmesv

L A

oAshtabula

Jefferson
O
I . ASMTABULA

O TT A WA

ft> rt Clinton,

SANDUSKY

O. ERIE

Fremont i

Cleveland

i j Chandon|

O Norwalk !

Elyria

' O | _
L O R A I N 1

I
CUYAHOGA i

! GEAUGA I J

I POTAGE

| T RUM BU LL

O Warren

SENECA
T,ff7n

HURON

I r~ IV^E D IN A 'SUMMIT! Rave

p L. 1 f I AkSn I Youngsfown I

M AH ONI NG '

_ |

i - -SU <

, Ashlar**
I O

I C RAWFORD !

BuCya,S | I. ASHLAND WAYNE

RICHLANO^ OWooster

O j '

_ _L Mansf.eld'-i

I - J ! -

i i

(__. J-, H O > M c <s

STARK |

Canton o^ |

J _C O_L U M B I A N A .

V j JACKSON j " l -

S C I T O

Portsmouth
j

Scale of Miles

^ y

THE PETROLEUM FIELDS
OF EASTERN OHIO IN I9f9.

Fio. 2.

J. A. BOWNOCKER 117

lachian field. Wells have been sunk in great numbers and no large area
remains untested. On the Woodsfield quadrangle alone about 2000 wells
have been drilled, and the number is very large on numerous other
quadrangles in Monroe, Washington, and Morgan Counties. The future
discovery of large pools is therefore very improbable, and the production
of 5,586,433 bbl. in 1903 will probaby not be equaled.

In Indiana, the producing territory in rocks of this age lies chiefly in
Gibson and Sullivan Counties in the southwestern part of the state.
This territory assumed commercial proportions in 1913, and in 1914 the
production of the state increased 40 per cent, the increase being from these
two counties. Later, oil was found in Pike and Daviess Counties, and
the territory to be prospected was thus largely increased. Of the 266
wells drilled for oil in Indiana in 1917, 187 were in these four counties.
Notwithstanding the yield from this territory, the production for the state
has decreased, that for 1917 being smaller than for any year since 1892.
While the outlook for an increased production from southwest Indiana is
not so unfavorable as it is from the Trenton limestone, the prospect is
not very promising.

The following composite record of two wells in Washington County
shows the important producing sands in Ohio and their relative positions:

THICKNESS, To BOTTOM,
FEET FEET

Pennsylvanian.

Meigs Creek (Macksburg) or No. 9 coal 5 15

First Cow Run or Macksburg 140-ft. sand 35 378

Macksburg 500-ft. sand 17 702

Macksburg 800-ft. sand 51 826

Salt sand 190 1095

Mississippian.

Mountain limestone (Big lime) 35 1325

Keener sand 55 1430

Big Injun and Squaw sands 115 1545

Berea sand 14 1953

Strenuous efforts have been made by drillers and producers to find
below the Berea sands that are the equivalent of the deep sands of
Pennsylvania, but it has been proved that when the Berea is passed,
in eastern Ohio, the last hope of securing oil is gone. The Clinton
sand should be present, but it lies so deep that the drill has not as
yet reached it.

The persistence, texture, and thickness of the sands in eastern Ohio
vary greatly. The deepest sand, the Berea, may be put in a class by it-
self for persistence and texture. It is extensively quarried near Cleveland
and it outcrops in the middle of Ohio from Lake Erie south to the Ohio
River. From its outcrop, the sand dips to the southeast and it is almost
invariably present in its proper place. In thickness, the usual range is
from 10 to 40 ft.; but in northern Ohio, much greater measurements have
been made. Lying interbedded in shales, the Berea is easily recognized

118 RISE AND DECLINE IN PRODUCTION OF PETROLEUM

and is an important guide, or key, rock of the driller. While this sand is
coarse grained, it is much less so than the higher sands of the eastern
part of the state. The workmen report it much harder to drill than the
overlying sands, and it therefore receives larger charges in torpedoing.
The Berea is productive in spots over much of eastern Ohio. In counties
north of Belmont and Guernsey, it is the only source of oil, and it is of still
more importance farther south. Nevertheless the total yield from this
formation is not large, and it is greatly surpassed by the Keener and Big
Injun sands. v.

The Big Injun and Keener sands are the largest producers of oil in
eastern Washington and in Monroe County where they are at their best.
Where these sands outcrop in the middle of Ohio, they are pebbly or
coarse grained and constitute the Black Hand and Logan formations.
Under cover, the same texture is maintained and the rocks yield readily
to the drill; their storage capacity is large. These sands are everywhere
present where due, but they are not so sharply delimited above and
below as is the Berea.

The Mountain limestone, or Big Lime, where present, is an excellent
guide, or key, rock of the driller. It is well developed in the eastern part
of Washington and in the southern half of Monroe County, but from there
it thins rapidly to the north and west and is rarely if ever reported. Its
thickness seldom reaches 100 ft. Along its outcrop in Muskingum, Perry,
and other counties this reck is known as the Maxville limestone. The
Big Lime is not a large source of oil, but an occasional producer is gotten in
it. The term Big Lime, however, is used by the drillers for two entirely
different rocks or groups of rocks in Ohio. As the following table shows,
the upper one forms the top of the Mississippian system; while the lower
one belongs to the Devonian and Silurian systems.

Maxville limestone, the Big Lime of southern Ohio.

Mississippian (Lower Carbon-
iferous)

f Keener sand
Black Hand and Logan. . | Big Injun sand

I Squaw sand
Berea sand

Devonian ,

Silurian

Olentangy and Ohio shales
Delaware limestone
Columbus limestone
Monroe limestone
Niagara limestone
Brassfield limestone

The Big Lime of the
Clinton sand fields.

The sands of the Pennsylvanian are much alike in properties. They
are coarse grained, light colored, open textured, and easy to drill. Lack
of persistence is a striking feature; this is particularly true of the First
Cow Run sand. They are beach or near-shore deposits, and their varia-
tions are a result of changes in direction and in strength of movement
of the water.

DISCUSSION 119

The sands of the Pennsylvania!! are not productive except in the
southeastern part of Ohio. The First Cow Run, or Macksburg 140-ft.,
sand is an important source of oil in Morgan, Washington, and Noble
Counties. Its place is in the Conemaugh formation and about 160 ft.
below the Pittsburgh coal. The Macksburg 500-ft. and the Macksburg
800-ft. sands are still more restricted in their producing area, which is
limited to northern and central Washington County.

The variation in depth of wells is notable. The range is from 12 ft.
(3.6 m.) to 2200 ft. (670 m.) and one of only 38 ft. is still being pumped.
Compared with other important fields, the wells have been small pro-
ducers. Very few have had an initial production as large as 500 bbl.
per day, and the maximum was about 2500 bbl. The wells are long lived,
which in a measure compensates for their small size. Thus one well, only
98 ft. deep, near Joy, Morgan County, is said to have been producing
continuously since 1872. The oil is nearly all of Pennsylvanian grade and
ranges in density from 42 to 50 Be". The color is dark green, red, or
black. Salt water is everywhere present.

The structural features of the oil-producing sands in eastern Ohio are
not conspicuous. The rocks dip to the southeast at a varying rate, in
most places from 25 to 40 ft. per mi. A few well-marked anticlines or
domes are found, the most conspicuous being the Burning Springs anti-
cline, which crosses the Ohio Valley about 12 miles east of Marietta. An-
other one is at Cambridge, but neither oil nor gas in large quantity has
been found with it. The Cow Run pool, in Washington County, is on a
well-marked dome. Smaller folds have been located in Washington,
Belmont, Harrison, and other counties, and oil or gas in most cases has
been found beneath them. Some of the larger fields, however, are not
known to be on structures of this kind. The contour maps of the oil sands ,
which the Federal Survey has been issuing in recent years, show oil in
almost all positions except synclines. Probably the three most important
features that determine the presence of oil are structure, texture, and salt
water.

Within the past few years Smith and Dunn, of Marietta, Ohio, have
patented a process for increasing the production of oil wells that have
been pumped. They force air into the oil sand under a pressure that
varies in most places from 40 to 350 Ib. to the square inch. This, it is
stated, increases the production on an average from 100 to 150 per cent.,
with a maximum of 800 per cent. 11

DISCUSSION

L. S. PANYITY,* Columbus, 0. (written discussion). Under the
subdivision of "Production from the Clinton sand field in Ohio," relative

" J. O. Lewis: U. S. Bureau of Mines Bull. 148 (1919).
* Chief Geologist, Ohio Fuel Supply Co.

120 RISE AND DECLINE IN PRODUCTION OF PETROLEUM

to the depth to the sand in Tuscarawas County, the wells are in all cases
at least 4500 ft. (1371 m.) in depth and the deepest well producing oil or
gas from the Clinton found that sand at a depth of over 5000 feet.

In regard to "how the oil got into its position," the possibility that
the main accumulations rest in shallow basins is untenable, as structure
maps indicate homoclinal accumulations. The main controlling factor
is lensing and differential cementation. This belief is further strengthened
by the presence of scattered gas wells down dip from the oil. The pres-
ent eastern edge of the oil fields in the Clinton is already at great depths,
which fact has prevented extensive prospecting still farther down dip,
but it is a question of time when deeper tests will be made. If the
water conditions remain as they are, water thus far having been found
in but a few wells, the homocline at lower structural levels promises
that newer pools may be opened up. Another point in favor is that the
Clinton, as well as all other formations, being deposited on the eastern
flank of the Cincinnati anticline, at the same time when the folding was
taking place, i.e., folding and deposition being contemporaneous, the
formations can be expected to thicken away from the axis. Thus, we
may expect a thicker Clinton stratum farther east and down dip. Should
an abundance of water make its appearance in the formation, structural
conditions must be more favorable; and as we have more pronounced
structures eastward, as noted from surface outcrops, they will offer
sufficient inducements for drilling.

Relative to the structure of the eastern, or shallow sand, fields, especi-
ally the effect of the Cambridge anticline upon production, the older
surveys have indicated this arch to take a northeast-southwest direction.
The writer's study of this structure indicates that the main fold takes a
southern and a little easterly direction; commencing at Cambridge, it
passes through Caldwell and Macksburg, and apparently extends farther
southward in the direction of the Burning Springs anticline of West
Virginia, which may prove to be a continuation of this fold. The south-
ward plunging axis brings gas accumulations just south of Cambridge
and oil pools are found all along this axis as far as the Ohio boundary
line at the Ohio River; thus we have good oil pools all along it south of
Caldwell, including the well-known Macksburg pool which is known to all
oil men. The secondary folds, which radiate from the main fold in a
northeasterly direction, also control the accumulations to the east. It
is the writer's opinion that the greatest'number of accumulations have
been directly caused by the general main fold known as the Cambridge
anticline and the secondary folds radiating from it.

It is true that there are many good pools not so situated, where a
different explanation is needed. North and west of the city of Cambridge
small scattered gas wells are found but not' what may be considered as
real pools. Here the anticline loses its prominence and the sand condi-

DISCUSSION 121

tions are entirely different; this phase has been discussed by the writer 12
in a former paper.

The Scio pool is often quoted as one of the large " off-structure"
accumulations. The main controlling factor here is the water level
on a homocline above which the oil is found. That the sand conditions
are not the main factors at Scio is brought out by the fact that the per-
centage of dry holes inside the producing territory is exceedingly small.
We have here a very extensive formation, what may be called a sheet sand
on a somewhat smaller scale than is generally understood. Oil accumu-
lates above the water and is found in almost every well drilled above the
water level, up the dip, until gas showings are encountered. Corning
offers a similar case, where the water level is a factor, however; the
normal dip is arrested to a considerable extent, giving a terrace structure,
and several smaller pools northeastward and along the strike are claimed
to be on small domes.

There have been very few quadrangles mapped by the Federal
and State surveys, thus the impression gained from them should not be a
criterion for the entire shallow sand production of the state. One
noticeable feature of the so-called "off-structure" accumulations here is
the way the pools adhere closely to the direction of the strike, and that
production is found along certain structural levels, which is very evident,
even though there may be considerable barren areas between pools.
In that section of the state where the structural conditions are homoclinal,
the prospector will do well to pay strict attention to these apparent
producing levels, and also to make a careful study of lensing.

12 Trans. (1919) 61, 478.

122 OIL FIELDS OF KENTUCKY AND TENNESSEE

Oil Fields of Kentucky and Tennessee

BY L. C. GLENN,* Ph. D., NASHVILLE, TENN.

(New York Meeting, February. 1920)

IN THE preparation of this paper the writer has drawn freely upon
the writings of Orton, Munn, Shaw, Mather, Miller, Hoeing, St. Clair,
Jillson, and others, as well as upon his own personal knowledge of the
fields of both states. It is to be regretted that certain data gathered by
him and his assistants last fall are not available for publication.

OIL IN TENNESSEE

A few wells drilled for brine for salt making in Tennessee between 1820
and 1840 obtained oil, but no definite search was made for oil until just
after the close of the Civil War. Active drilling was then begun in
Over ton and counties southwest of it on the eastern half of the High-
land Rim. A number of strikes were made at shallow depths in the
basal part of the Mississippian but the wells were soon exhausted and
abandoned. Drilling was revived, about 1892, when the Spurrier dis-
trict in Pickett County was developed and was followed by the Riverton
district in the same county in 1896. A pipe line was laid from the Wayne
County, Ky., fields and about 60,000 bbl. of oil were run before a very
heavy slump in the production, a failure to find an extension of the field,
and excessive local taxation caused the removal of the pipe line in 1906.
There was then no production in Tennessee until the discovery, in 1915,
of oil near Oneida, Scott Co., at about 950 ft. (289 m.) in fissures in
the Newman or St. Louis limestone. This field, however, soon failed
and was abandoned.

In 1916, oil was found at Glen Mary, Scott Co., in the Newman lime-
stone at a depth of 1232 ft. (375 m.) A number of wells have since
been drilled there, some of which were dry while others, close by, were
producers. The largest one yielded, at first, about 340 bbl. per day and
produced for several months, when it suddenly went dry. Several of the
first wells began at 6 or 8 bbl. per day and are still maintaining that
output. Production is from a fissured part of the limestone and varies
greatly in accordance with the size and extent of the ramification of the

* Consulting Oil Geologist and Professor of Geology, Vanderbilt University.

L. C. GLENN 123

fissures. In some areas, the limestone has no fissured zone and wells go
through it without obtaining even a show of oil. Fissuring, when present
is not always at the same horizon in the limestone and failure to obtain
a well in one location does not necessarily mean that the next location may
not be a successful producer. The production at present is probably
not over 1000 bbl. a month. The oil is shipped to Somerset, Ky., in tank
cars and there delivered to the Cumberland pipe line.

The limestone in which the oil occurs has, so far as has been ascer-
tained, a monoclinal structure and rises gently to the west. There is only
a little gas with the oil and little or no salt water is encountered. No
production curves can be given since the wells vary greatly. Some decline
rapidly and fail in a few months while others show scarcely any decline
after several years and bid fair to have a long life as pumpers of about
6 to 8 bbl. per day. The gravity is from 36 to 38 Baume*.

There is now considerable activity in both leasing and drilling, espe-
cially in the western half of the Highland Rim, west and northwest of
Nashville, although the eastern and southern parts of this Rim are also
receiving some attention. The surface of the Highland Rim is almost
everywhere of Mississippian age and is underlaid, at a maximum depth
of not more than a few hundred feet, by the Chattanooga black shale.
Oil shows are often found just above or just below this shale. Much of
the activity has been stimulated by the finding of oil in Allen County,
Ky., under geological conditions very similar to those that obtain in the
adjacent Highland Rim section of Tennessee.

There has been occasional deep drilling in Tennessee for a number of
years, especially in the Central Basin, where the surface rocks are of
Ordovician age, in the hope of obtaining a deep pay usually spoken of as
the Trenton. All such attempts in this part of the state have so far
failed. There have been a few slight shows and a little gas has been
found, but no good sand has been encountered. The only Ordovician
production from Tennessee has been that in Pickett County.

A half dozen holes or more-have been bored in the last 10 years in the
western part about Memphis, and to the north of it, near the axis of the
great trough in which the Gulf embay ment deposits have been laid down.
These wells usually range from 2000 to 3000 ft. (609 to 914 m.) in depth
and several of them reported shows of oil or gas in the lower part of the
section. Very recently, activity in this part of the state has been re-
vived and preparations for further deep testing of the embayment de-
posits in the vicinity of Reelfoot Lake in the northwestern corner of
the state are now being made.

The history of attempts at oil production in Tennessee give meager
data on which to base any predictions of a large future oil production.
No well-defined oil sands of any considerable extent are known, although
large areas of the Newman limestone exist beneath the Cumberland

124 OIL FIELDS OP KENTUCKY AND TENNESSEE

plateau, under conditions very similar to those at Glen Mary, and
remain untested by the drill. Should portions of these be notably
fissured, they might furnish an oil field of much importance. It is
entirely possible that oil may be found in various parts of the High-
land Rim, either in the Waverly rocks close above the Chattanooga
black shale or in Onondagan or Silurian limestones close beneath it.
Such rocks appear to the writer as the most promising for further
drilling. Oil is much less probable in the Ordovician rocks, since sand
and other conditions do not usually seem favorable there.

The surface of the Cumberland plateau consists of Pennsylvanian
sandstones and shales of Pottsville age that attain a maximum thick-
ness of 1000 ft. (304 m.) or slightly more, beneath the general plateau
level. So far, there is no evidence, either from occasional wells that
have gone through them or from their character as they outcrop on
either side of the plateau, that the Pottsville rocks contain oil in
Tennessee. Should it occur, it would most probably be found in that
portion nearest the Kentucky line, as oil is obtained from several Potts-
ville horizons in Knox County, Ky., not far to the northeast.

The Gulf embayment sands and clays of western Tennessee attain
a thickness in excess of 2500 ft. (762 m.), and may be 3500 ft. (1066 m.)
thick along the axis of the trough, before the Paleozoic floor on which
they rest has been reached. The lower part of these embayment rocks
are of Cretaceous age and are the equivalents of the rocks that yield
oil and gas in northwestern Louisiana. It is possible that they may
contain oil in western Tennessee, although structural relations are so
obscured by a blanket of surficial sands and by the general flatness of
the region that drilling there must be largely a matter of chance and
success mainly the result of luck. It is further possible that some part
of the old Paleozoic floor beneath the embayment deposits may contain
oil, although there is no means of determining either the lithologic
character or the structure of the older rocks from surface inspection.
Where they go under the embayment deposits near the Tennessee
river, they vary in age from Silurian to Mississippian. Their surface
is usually regarded as a beveled erosional one, so that it is probable that
the floor of the embayment may, in the deeper parts, be composed of
Ordovician rocks.

OIL IN KENTUCKY

Oil is produced in Kentucky in a large number of separate areas,
most of them small. They are widely scattered through the east central,
eastern, southeastern, southern, and southwestern parts of the state.
Only one of these, situated in Estill and Lee Counties and generally
known as the Irvine field, is of very great size. This includes a recent

L. C. GLENN 125

extension to the southeast known as the Big Sinking Creek field. The
most northeasterly are the Fallsburg and Busseyville pools in Lawrence
County, and the most eastern is the Beaver Creek field in Floyd County.
Closely connected with the Irvine-Big Sinking pool in the central eastern
part of the state are the Station Camp, Lost Creek, Campton, Stillwater,
and Cannel City pools; and a short distance to the northeast is the
Ragland pool. In the southeastern part of the state is the Knox County
area north of B arbour ville, and a number of small pools in Wayne County.
In Lincoln County, there is a small area northeast of Waynesburg. In
the southwest, there are the Barren County fields, a small area in the
eastern edge of Warren County and a number of small detached areas
in Allen County, the most important of which are grouped about Scotts-
ville. Elsewhere, there are a few isolated wells or very small groups of
wells not important enough to be given specific mention.

The first oil in Kentucky was discovered, by accident, in 1819 while
drilling for a salt well near the south fork of Cumberland River in
what is now McCreary County. The oil came probably from the
Mississippian. The next find was made, in 1829, on Renox Creek near
Burksville, Cumberland County, and was from Ordovician rocks. This
well flowed for many miles down Cumberland River, caught fire, and
burned for some time. Later its products were used for medicinal and
other purposes, until about 1860.

Following the discovery of oil in Pennsylvania, discoveries were made
in Wayne and other counties along the Cumberland river, from 1861 to
1866. Most of the oil obtained was shipped by barges down the Cumber-
land to Nashville, although a part was refined locally. Just after the
war, there was renewed interest in the search for oil and additional dis-
coveries were made, especially in Allen and Barren Counties, where oil
was found close beneath the Devonian black shale. Interest waned
between 1870 and 1880, but was revived during the last two decades of
the century, when additional discoveries were made in Barren County west
of Glasgow, in Lawrence County on Big Blaine creek, and in Floyd and
Knott Counties on the right fork of Beaver creek; while in Wayne
County renewed activity led to important discoveries in a number of
localities. The most important production in Wayne was found in the
Beaver sand in the lower part of the Waverly, but some oil was also
obtained below the black shale. During the two decades from 1880 to
1900, the average production for the entire state was not over 5000 bbl.
per year; the maximum production was in 1899 when 18,280 bbl. were
produced.

The modern period in the development of oil in Kentucky may be
said to date from the discovery of the Ragland field in Bath County, in
1900. In this field, oil was found in the Onondaga limestone at a depth
of 300 to 380 ft. (91 to 115 m.) beneath the Licking River valley. By

126 OIL FIELDS OF KENTUCKY AND TENNESSEE

1904, the field was practically drilled up and production since then has
gradually declined until it is very small. The Sunnybrook pool, Wayne
Co., was discovered in 1901. Oil was obtained from the Trenton, which
came to be known locally as the Sunnybrook sand. There was a consider-
able yield, but it was short lived and within a few years the field had been
abandoned. Many further attempts have since been made to obtain
oil from the Trenton, or Sunnybrook, both in Kentucky and in Tennessee,
but so far they have been without success. Following the Sunnybrook
development, much drilling was done elsewhere in Wayne and adjoining
counties, and a number of small pools were developed, chiefly in the
Beaver sand.

In 1901, oil was found in the northern part of Knox County on Little
Richland Creek, near Barbourville. The oil came from three sands
in the Pottsville, named in descending order the Wages, Jones, and
Epperson. The wells were small producers and were practically all
abandoned in a few years. Recently there has been renewed activity in
the Barbourville region, but nothing noteworthy has developed.

In 1903, the Campton pool was discovered and by 1909 had been
drilled up. Oil was found in the Onondaga limestone. Many of the wells
have since been abandoned, but others in the field are still pumping
% bbl. or more per day. Shortly after this, wells were gotten at Still-
water on the eastward continuation of the Campton structure. They
were very similar to the Campton wells and have had a similar history.
The same structure yielded oil at Cannel City in 1912, and by 1913 a
production of 12,000 bbl. per month had been attained. This rapidly
declined, however, and the production today is merely nominal.

For many years oil has been known near Irvine, having been originally
found in borings made for salt wells. Soon after the discovery of oil
at Campton some shallow wells were bored at Ravenna, near Irvine, on
the westward continuation of the structure on which the Campton wells
were located. This structure is now generally known as the Irvine struc-
ture. The wells were very shallow, but yielded considerable oil for a
number of years, until their decline led to the removal of the pipe line
that had been laid in the early years of their development, and they were
entirely abandoned. In 1915, a well drilled 3 mi. northeast of Irvine
started the development of the present Irvine fields and ushered in the
present period of intense activity of oil development in Kentucky. The
producing sand is the Onondaga limestone, just beneath the black shale,
and is generally known as the Irvine sand. The field was rapidly ex-
tended eastward and by 1917 had reached the Pilot section near Torrent,
making the field about 12 mi. long and from 1 to 2 mi. wide. In 1918,
there developed what might be called a southeastward extension of the
Irvine field along Big Sinking Creek. Development in this new area

L. C. GLENN

127

was rapid and by the early part of 1919 its southern limits had been
reached a mile or two northwest of Beattyville.

On Station Camp creek, some 8 mi. south of Irvine, a small pool was
found in 1916, at less than 100 ft. (30 m.) beneath the valley floor. It
was drilled very closely and was soon practically exhausted. In similar
fashion another small, shallow pool was discovered and developed on
Ross Creek. Decline has set in there also but exhaustion has not yet
been reached. About these two are grouped several still smaller produc-
tive areas of like character but of still more recent development.

Meantime, in 1903, oil was discovered at Busseyville and Fallsburg,
Lawrence Co., in the Berea sandstone about 1400 to 1600 ft. (426 to 487
m.) in depth. The wells are small but maintain their production for
years with but slight decline.

Although oil was produced in Allen County about the close of the Civil
War, it was not until about 1915 that the modern period of production
there was ushered in by the drilling near Scottsville of a number of small
wells 200 to 300 ft. deep. The oil came from close beneath the black
shale from either Onondaga or Niagara limestone. Development has
been checked until very recently by inadequate transportation facilities.
Most of the development is to the south of Scottsville, but there are
several small areas in the northwestern part of the county and recently
an important well or two have been drilled just across the line in the
eastern edge of Warren County. Wildcat wells are being drilled in
numerous places in nearly all sections of the state except the central and
northern part, where the surface rocks are of Ordovician age, and in the
extreme western part within the area of the Mississippi embayment
deposits.

GEOLOGY OF KENTUCKY OIL FIELDS

A list of geological horizons designed to include all sands that have at
any time furnished oil in Kentucky would be quite lengthy. A list con-
fined to horizons producing oil today in commercial quantities follows:

PRINCIPAL PRODUCTIVE OIL SANDS IN KENTUCKY

PERIOD
Carboniferous

EPOCH
Pottsville

Mississippian Waverly

OIL AND GAS HORIZONS
Beaver

Horton of Floyd and
Pike ' KnottCo.
Salt
Berea of Lawrence Co.

Jones f of Knox Cos.
Epperson J

Devonian

Onondaga
(Corniferous)

Stray and 1 of Wayne
Beaver } and Mc-
Creek J Creary Cos.

Of Olympia, Ragland, Cannel City, Stillwater,
Campton, Irvine, Big Sinking Creek, Ross Creek,
Station Camp Creek, Lanhart, Buck Creek,
Miller's Creek, Heidelberg, Barren Co., Warren
Co., Allen Co., Ohio Co.

128 OIL FIELDS OF KENTUCKY AND TENNESSEE

In Floyd and Knott Counties, four sands occur in the lower part of
the Pottsville; these, in descending order, are: the Beaver, Horton, Pike,
and Salt sands. They are all sandstones and each varies in thickness
from less than 50 ft. (15 m.) to more than 300 ft. (91 m.). The interval
between them also varies from a few feet to over 100 ft., making it practi-
cally certain that the sands split and reunite in such irregular ways that
correlation of them is uncertain. In Knox County, the Wages, Jones,
and Epperson sands of the lower Pottsville are also sandstones and vary
considerably both in thickness and in interval. Their correlation from
well to well is doubtful at times and no correlation has so far been possible
with the Floyd County sands. The Berea sand of Lawrence County is a
medium grained sandstone that usually runs from 50 to 100 ft. in thick-
ness and lies at the base of the Waverly.

In Wayne and McCreary Counties, the principal oil-bearing horizon
is a cherty, geodal limestone known as the Beaver Creek sand. It lies
just above the Chattanooga black shale and forms the basal member of
the Waverly. It varies greatly in thickness, texture, and porosity and
the production of the wells in it varies accordingly. In some cases, a
similar oil-bearing limestone is found near the top of the Waverly in these
counties and is known as the "Stray sand." It is usually from 10 to 30
ft. (3 to 9 m.) thick.

The Onondaga, or Cornif erous, limestone is by far the most important
oil-bearing horizon in the state. It lies close beneath the Genesee or
Chattanooga black shale. It is a soft brown, porous to cavernous, mag-
nesian limestone which, in the Irvine fields, thickens to the east from 20
or 30 ft. (6 to 9 m.) about Irvine to from 70 to 95 ft. on Big Sinking Creek.
The pay exists in from one to several streaks that have no regular dis-
tribution or position. Between the pay portions, the limestone is hard
and close grained. In Allen County, the pay may extend down into
fissured or porous limestone of Silurian age.

Genuine sandstones occur in Kentucky as oil-producing sands only
in the Pottsville and Berea, and their aggregate production amounts to
less than 2 per cent, of the total production of the state; 98 per cent, of
the production comes from limestones. In a sandstone, the distribution
of porosity is usually more uniform than in a limestone, where the porous,
fissured, or cavernous condition is apt to be irregular in occurrence. This
difference in the nature of the two rocks explains the marked differences
in the amount of pay, in the yield of nearby wells, and the freakish
occurrence of dry holes in the midst of production where the sand is a
limestone.

If one takes the percentage of the present production from the several
sands given in the preceding table, it will become evident that the pro-
ducing horizons in the state vary greatly in their relative importance and
that the one sand of prime importance is the Onondaga, or possibly, the

L. C. GLENN 129

Onondaga linked with the Niagara for Ohio and parts of Barren, War-
ren, and Allen Counties. The aggregate production, however, from these
counties is so small, relatively, that the importance of the Onondaga as
the premier oil horizon of the state is not materially diminished.

APPROXIMATE YIELD OF OIL BY GEOLOGICAL HORIZONS IN KENTUCKY

PER CENT.

Pottsville of Knox, Floyd, and Knott Counties ^ to 1

Berea of Lawrence County 1

Stray and Beaver Creek of Wayne and McCreary Counties . . 2

Onondaga, of Allen, Barren, Warren and Ohio Counties (?)... 4

Onondaga, of Irvine-Big Sinking and other nearby areas 92 to 92>

STRUCTURE IN RELATION TO OIL OCCURRENCE

All of the oil fields in the central eastern part of the state are on the
eastern or southeastern flank of the Cincinnati anticline. The rocks in
which they occur rise gently to the west out of the great Appalachian
trough, whose axis lies along the extreme eastern border of the state.
Oil has migrated up the slope of these rocks to the westward until ar-
rested by an anticline with a northeast-south west axis, whose northwestern
limb has usually been faulted in simple or compound fashion. The
most important part of the great major anticline of this region extends
from near Irvine eastward to Paint Creek, though the extreme limits are
more remote at either end. Subordinate and somewhat parallel anti-
clines occur in the Ragland and in other minor fields near the Irvine field.
There has apparently been some cross folding also that has corrugated
the slope up which the oil has migrated and concentrated it in certain
more favorable localities. The Irvine field, however, presents certain
anomalies worthy of mention in this connection. The axis of the anti-
cline pitches to the northeast at a rate more than sufficient to cause the
migration of oil westward along it and without, so far as the writer knows,
any cross folding sufficiently strong to check such movement; yet oil is
found along this axis at intervals from Irvine eastward to Cannel City
with only a few dry areas between the separate pools. Again, the east-
ern end of the Irvine field proper has a broad southeastward tongue that
extends a number of miles down the dip in the Big Sinking Creek area.
It seems that this oil should have migrated farther up the slope to the
northwest and have been found nearer the axis, since it has salt water
below it to push it onward.

In the Lawrence field, the Berea sand seems to have an anticlinal
structure, which combined, perhaps, with difference in porosity may
explain the occurrence of the oil there.

In the Pottsville sands, in Floyd and Knott Counties, oil moving up
the dip to the westward has been arrested either by slight terraces or by

VOL. LXV. 9.

130 OIL FIELDS OF KENTUCKY AND TENNESSEE

encountering tight places in the sand. There is no anticlinal structure.
Similar structural conditions prevail, so far as the writer knows, in the
Knox County wells north of Barbourville.

In the Wayne County field, the oil favors, according to Munn, the
sides and bottom of synclinal troughs that slope gently eastward.

In Allen County, recently published work by Shaw and Mather show
a number of small anticlines and domes with an area of 2 to 3 sq. mi.
each, superimposed upon a prevalent northwestward dip of perhaps 40 ft.
(12 m.) to the mile. These have a closure of 25 to 30 ft. (7 to 9 m.) or
less, and their location, from a study of the surface, is often difficult or
impossible because of lack of exposures. These same features and lack
of exposures characterize much of Barren County and the eastern part of
Warren County. In the western part of Warren County, exposures are
better and pronounced doming and terracing occurs. These structures
have yielded considerable shows of oil near Gasper River.

Water usually follows the oil in the Onondaga rather closely. It
soon begins showing in the wells in the lowest part of the structure and,
as time passes, invades the field farther and farther up the dip. Water
has thus encroached upon part of the Irvine field and has appeared in
the Big Sinking field. Concerted efforts should be taken by operators
there to combat this invasion.

TECHNOLOGY

Drilling was formerly by standard rig; and in deep tests in wildcat
territory this method is still used. Most of the known production can,
however, more easily be reached by drilling machines. Wells in the Allen
fields 250 to 300 ft. (76 to 91 m.) deep cost about $1000 complete. In
the Big Sinking field, wells 800 to 900 ft. deep cost about $3500; while
those 1000 to 1200 ft. deep cost from $5000 to $6000. Prices for drilling
tend to rise in harmony with all other prices at present.

The size of Kentucky wells varies greatly both for the various pools
and for adjacent locations in the same pool. This is true especially if
the sand is a limestone. The rate of decrease also varies greatly. Re-
liable determinations of this rate are made difficult by the development
of the more important pools having been so recent that their records of
production extend over only a very few years. This difficulty is further
increased by the fact that pipe-line facilities have until very recently been
entirely inadequate to take care of the production. In the Allen County
fields, transportation conditions have been especially bad, and while
partly remedied are not yet entirely satisfactory.

In Lawrence County, wells in the Berea sandstone come in at from
4 to 8 or 10 bbl. and show only a very slow decline over a long period
of years.

In Floyd County, where the oil is also derived from sandstone, the

L. C. GLENN 131

initial production is likewise small but is well maintained. Some of the
wells drilled 10 to 20 years ago show only slight decline.

In Wayne County, where production is from a limestone, the initial
yield varies greatly, though some of the largest wells produced from 100
to 500 bbl. daily for a short time. The average initial production, how-
ever, is well below 100 bbl. These wells soon settle to 20 bbl. or less per
day and then usually show only a slight further decline. In some
cases there has been practically no decline in 15 years; in other cases, the
yield in that time has decreased to a barrel or two or even less. Many
of these old wells have been overhauled recently and put on a vacuum
with a gratifying increase in yield.

In the Irvine district, initial production also varies greatly. The
average, given by Shaw, for successful wells drilled between October,
1915, and February, 1917, is about 39 bbl., and the producing wells were
89 per cent, of the total number drilled. Few exceeded 100 bbl. each.
In Big Sinking Creek a number of wells have had an initial production
of several hundred barrels and a few have probably yielded 1000 bbl.
per day. The decline in the Irvine field by the end of the first year has
been to about 10 per cent, of the initial yield, although some wells have
held up considerably better. This rate of decline has been due to the
porosity of the sand and the close spacing of the wells in many cases.
In parts of the Station Camp and Ross Creek pools, wells have been
spaced one to an acre or less. The well spacing in the Big Sinking field
has also been entirely too close on certain properties and has been at-
tended with a rapid decrease in production.

In the Allen County region, about 75 per cent, of the wells drilled
have been successful. Initial production for the larger wells has varied
from 25 to 100 bbl. per day with a few exceptional wells yielding 200 to
300 bbl. The gas pressure behind these largest wells, however, is quickly
relieved and in a few days they decrease greatly. By the end of the first
month, the larger ones yield from one-fourth to one-third of their initial
production, while the smaller ones hold up somewhat better. These
smaller wells come in at from 5 to 20 bbl. per day.

In Barren County, a well recently abandoned because of decreased
flow and the eating away of the casing produced oil for over 40 years and
during that period showed a remarkably low decline curve. It was prob-
ably next to the oldest well in the country at the time of abandonment. 1

Future production curves and tables have been published by the
Internal Revenue Department for Floyd County, Beaver Creek in Wayne
County, Ragland and Irvine, in its "Manual for the Oil and Gas Industry. "

The oil varies considerably in character. Most of it is dark green
by reflected light, but dark brown when seen by transmitted light in thin
films. A little amber oil has been reported from Barren, and occasion-

1 A well in Wirt County, W. Va., drilled in 1860 is still producing.

132 OIL FIELDS OP KENTUCKY AND TENNESSEE

ally elsewhere, but the quantity of such oil is negligible. In gravity,
it ranges from 26 to 45 Be". In the Floyd field, the average is about 40.
In Wayne county, it varies from 36 to 43. In the Irvine field, the
average range is 30 to 36. In the Ragland field, the average is 26
or 27. Allen county averages from 35 to 38; and Barren about
40 to 42. The gasoline content is usually high.

In the Lawrence, Floyd, Knox, and Wayne County fields, no ab-
normal values have attached to lands; but in the Irvine district values, es-
pecially in Big Sinking field, have rapidly risen until prices of $2000 to
$5000 per acre have been reached with extra royalties at times. In
Allen County and near the Moulder well in the eastern part of Warren
County, high prices have also been given recently for acreage. Wildcat
acreage has, in many places, been held at high figures when compared
with equal grade acreage in many other states and much develop-
ment in certain sections has been retarded by these prices.

The great bulk of the oil in Kentucky is transported by the Cumber-
land pipe line, which has lines serving practically all of the eastern and
southeastern parts of the state. It does not, however, reach the fields of
Allen and adjacent counties. Until recently its capacity was inadequate
to care for the possible full production. A little oil in the eastern fields
is handled by short private lines, by barges, or by tank cars. In Allen
County, several small pipe lines gather the oil and deliver it to loading
racks at Scottsville and Bowling Green for shipment to Nashville, Louis-
ville or elsewhere.

FUTURE POSSIBILITIES

There is a good chance for finding a number of small pools in the Potts-
ville and the Berea in the eastern part of the state on small structures or
under favorable conditions of the sand. Such pools may be expected to
have the general character of those in Lawrence, Floyd, and Knox
Counties, starting with a small production, but sustaining it well for a
long period.

The Onondaga oil is seemingly confined to a narrow belt near the
outcrop of these rocks in the central eastern part of the state, which
has already been pretty thoroughly tested and developed. The writer
looks for no large new pool from that horizon there. Where the Onon-
daga crosses the saddle between the Cincinnati and Nashville domes in
the Barren, Warren, and Allen areas, there doubtless remain a number
of new finds; but the difficulty in determining the structure because of
the prevalent surface soil covering will make their discovery either a
matter of slow detailed work or of chance.

There should be chances of finding oil on the sides of the basin in which
the west Kentucky coal field lies where the Mississippian, Devonian, and
perhaps Silurian rocks rise from that basin to the east and southeast,

DISCUSSION 133

wherever domes, terraces, or other favorable structures can be located.
The chance on the south side of this basin is less favorable because of
the extensive faulting there.

Within the West Kentucky coal field, the writer believes the only
favorable chance of finding oil is along the Gold Hill-Rough Creek dis-
turbance and conditions there are complicated because of the severity
of the folding and faulting. In the Gulf embayment deposits of West
Kentucky, there are no known structures; and it is too soon to make
prediction worth anything until the results of the testing soon to be done
in the nearby Reelfoot Lake district in Tennessee are known. Much
light should then be thrown on the oil possibilities of these embayment
rocks in Kentucky.

Little or no oil need be expected in the Ordovician or in any older
rocks and drilling in any part of the central blue grass limestone region
of the state is practically money wasted.

DISCUSSION

MORTIMER A. SEARS, Huntington, W. Va. (written discussion). In
dealing with the future possibilities for oil and gas in Kentucky, I regret
that Doctor Glenn has failed to mention the Paint Creek Dome, which
lies in parts of four counties, viz., Johnson, Magoffin, Morgan, and Law-
rence. This immense structural uplift has possibilities second to none
in the state. It lies along the line of structural uplift known to extend
from the Irvine field through Kentucky, and into West Virginia, where
it is known as the Warfield anticline.

In an article that I wrote for the Oil and Gas Journal (May 21, 1917),
I stated the geologic facts in connection with this field, which at that time
was strictly a wildcat proposition. It is true that wells have been put
down at various times since about 1860, but such operations were spas-
modic and haphazard. So far as I know there had been no geologic
report relating to oil and gas upon this area at the time I made my exami-
nation (February, 1917) except in the form of a communication from
Prof. J. P. Leslie to the American Philosophical Society in 1865. After
February, 1917, development dragged along slowly until about a year
ago, when more energetic measures were inaugurated, with the result
that about 20,000,000 cu. ft. of gas per day has been developed and
several oil wells having capacities of from 3 to 50 bbl. per day have been
brought in.

Commercial quantities of gas occur in the Weir sand at a depth from
the surface of about 850 ft. (259 m.) ; it varies in thickness from 20 to
40 feet. Part of the product is sold to the Central Kentucky Natural
Gas Co., and part to the Louisville Gas and Electric Co. These two com-
panies have main gas lines extending through the field about 5 mi. from

134 OIL FIELDS OF KENTUCKY AND TENNESSEE

the particular area in which gas has been found. Lateral lines have
been laid and compressor plants are in operation.

The largest oil wells in the field find their product in the Weir sand
also, although commercial quantities of oil have been found in the Berea.
The Weir sand appears to be a l 'genuine sandstone" and seems to prove
an exception to Doctor Glenn's statement that genuine sandstones occur
in Kentucky as oil-producing sands only in the Pottsville and Berea.
It may correspond to one of the oil sands of Wayne and McCreary
Counties, but it certainly cannot be called a "geodal limestone."

The Keener, also, has produced small amounts of oil. It is from this
sand that a well recently brought in produced an oil of 51 Be*, gravity.
The weir oil runs about 38 Be*. The Cumberland Pipe Line Co. expects
soon to lay a line into the field.

The last well brought in showed the Weir sand to be over 60 ft.
(18 m.) thick with a 16-in. (40-cm.) break. Thus far, wells drilled to
the Onondaga (Coniferous) have proved disappointing and no pro-
duction has been found in the Clinton. Comparatively few wells are
drilled below the Weir so that it is yet too early to condemn the lower
formations.

Leases are constantly, changing hands. Very little acreage remains
in the hands of the land owner. Whenever a well is brought in, leases
sold on adjacent property bring from $100 to $150 per acre. With the
opening of spring there is no question but that this area will be the scene
of the greatest activity in the state of Kentucky.

WILBUR A. N. NELSON,* Nashville, Tenn. (written discussion).
Certain pertinent facts in regard to the oil produced in Tennessee in the
past and to the extension of the different formations of Allen County,
Kentucky, into Middle Tennessee are not given in this paper.

The very heavy slump in production that occurred in the old Riverton
Spurrier district of Pickett, Tenn., was due to fresh- water troubles.
A recent study of the water troubles of this field brings out these facts:
Under the Chattanooga " black" shale occurs a practically uniform bed
of Ordovician limestone, bedded or creviced so as to permit a connection
between the different gas shows in the upper part of the limestone
immediately under the black shale and the oil horizons in the base of the
limestone, some 165 to 270 ft. below the black shale. In the old wells,
the casing was set below the gas shows and just above the oil horizon.
That the release of the gas pressure permitted the fresh water to flow
down through the limestone joints, bedding planes, or fractures to the
oil horizon and thus drown out the well, seems to have been proved by
Mr. J. H. Compton, of Riverton. Several years ago he reset the casing
in one well above the first gas show and, after plugging the other wells,

* State Geologist, Tennessee Geological Survey.

DISCUSSION 135

above the gas horizon, started pumping. After several weeks, the well
again commenced to produce oil.

A structural report recently made on this area by the Tennessee
Geological Survey, in cooperation with the U. S. Geological Survey,
shows that the best old producing wells were located on the crest and
north flank of a long narrow anticline extending in a direction of approxi-
mately north 60 east and that the oil probably occurs in pools of small
extent with a radius of about J^ mi. Several similar anticlines were
mapped in this district, which are yet untested. The Cumberland Pipe
Line Co. laid a 2-in. line into this field in 1902, which was removed in
1905, due to a decline in oil production but primarily to the levying of a
$10,000 annual tax on the line by Pickett County. During this time
58,776 bbl. of oil were piped from this field, of which over 36,000 bbl.
came from one well, known as the Bobs Bar well, which shortly went to
water.

In Sumner County, Tenn., and in adjoining counties to the west and
southwest on the Highland Rim, there is at present much drilling going
on, but the majority of these wells have been drilled without paying any
attention to structure. This was recently shown in Sumner County,
which joins Allen County, Ky., on the south. A detailed structural map
of part of this county made by the Tennessee Geological Survey, in
cooperation with the U. S. Geological Survey, shows that of over 30
holes drilled only two were located on favorable structure. But on that
particular dome, one could have little hope of finding oil, as the oil horizon
had been cut through on the south flank of the dome. The structurally
favorable places are still untested.

In Allen County, Ky., around Scottsville, the oil is found at three hori-
zons below the Chattanooga black shale. These three sands are not
always present at one place; and when present, as a rule only one is
producing. The upper, sometimes the two upper, sands are considered
of Devonian ^ge and probably correlate, in Tennessee, with the Pegram
limestone. The lower sand, which produces most of the oil to the south
of Scottsville, is thought to be of Silurian age and to be Louisville limestone,
as this formation outcrops in Sumner County, Tenn., just south of Allen
County, Ky., at the base of the Chattanooga black shale, the Corniferous
beds of Devonian age being absent.

The location of the old shore line of the Pegram limestone, as it is
known in Tennessee, and of the Corniferous limestone, as it is known in
Kentucky, is important. Exposures of this limestone are not known
south of Petroleum, Allen County, Ky. No outcrops are known in
Sumner County, Tenn., but it appears again 12 mi. (19 km.) west of
Nashville, at Newsom Station, where it has a thickness of 3 ft. (0.9 m.) ;
a few miles farther west, at Pegram, in Cheatham County, it has a thick-
ness of 12 ft. From these exposures it would appear that this shore

136 OIL FIELDS OF KENTUCKY AND TENNESSEE

line would extend from Newsom Station northeastward through Cheat-
ham and Robertson Counties, Tenn., probably passing in the vicinity
of Springfield, and crossing the state line in the proximity of the north-
east corner of Robertson County, near Mitchellville. All territory as
far west of this area as the Tennessee River is underlain by Devonian
limestones. A well was brought in, in January, 1920, in Simpson County,
Ky., about 3 mi. from the northeast corner of Robertson County, Tenn.
in a very peculiar sandy limestone 61 ft. below the Chattanooga black
shale. The sand was penetrated to a depth of 7 ft. and may be a
phase of the Harriman chert of Oriskany age, which outcrops about
50 mi. to the southwest near Cumberland City, Stewart County, Tenn.
The shore line of the other supposedly oil-bearing limestone, the
Louisville limestone of Silurian age, is of interest because of the effect
it would have on possible oil territory in the counties on the western
Highland Rim of Tennessee. In Sumner County south of Westmoreland,
it is 20 ft. thick, while about 25 mi. to the southwest near Ridgetop, in
Robertson County, it only shows a thickness of 10 ft. Farther to the
southwest, in southern Cheatham County around Pegram, it is very
thin, having a 15 ft. exposure. On the western edge of the Highland
Rim along the Tennessee River, this formation changes to a shaly phase,
known as the Lobelville, which varies in thickness from 1 to 75 ft. These
facts would indicate that the extent of the limestone phase of the Louis-
ville formation would lie just to the southeast of the present edge of the
Highland Rim on the Middle Basin of Tennessee, as far south as Pegram,
and that at this point the line would turn to the northwest, swinging back
into Kentucky. The extreme thinness of the formation, except in the
northern part of Sumner County and probably in the northern part of
Robertson County, would indicate that only in these two areas would
it be thick enough to act as a commercial oil reservoir. The long narrow
embayments in which this and the overlying formations were laid down
make it probable that there are areas in the northern Highland
Rim counties lying outside of these old embayment areas in which these
formations were never deposited. In the more southern counties on the
Highland Rim west of Nashville, overlapping formations come in between
the Louisville limestone and the Chattanooga black shale, which would
keep this formation from containing oil if such oil is derived from
the Chattanooga black shale. That this formation is probably absent
in the southwestern part of Robertson County is indicated by the fact
that a recent well on Sulphur Fork, 6 mi. southwest of Cedar Hill, which
went to a depth of 1015 ft. and passed through the Chattanooga black
shale at 615 ft., encountered no water, oil, or gas below the Chattanooga.
This hole probably passed through the rocks of Trenton age at 950 ft.
The presence of blue phosphate sand in the limestone above this level
is taken as evidence of the presence of the Hermitage formation of Tren-
ton age at this depth.

DISCUSSION 137

In western Tennessee, two deep tests are being'drilled, one in Lake
County at Proctor City on the west side of Reelfoot Lake and the other
in Obion County near Walnut Log on the northeast side of Reelfoot Lake.
From numerous exposures of the formations just under the loess bluffs
northeast of Reelfoot Lake, it is thought that there is a marked anti-
clinal area just to the northeast of Walnut Log and extending over the
Tennessee state line into Kentucky. The oil and gas rights on Reel-
foot Lake, which belongs to the state of Tennessee, have been leased
by the Governor to the men who are drilling near Walnut Log. This
hole is on land joining the state property. Among other things the state
requires that the well be drilled to a depth of 3000 ft. The Paleozoic
floor of the gulf embayment should be reached inside of that distance,
while the formations producing oil in the northwest corner of Louisiana
should be reached at about 2200 ft.

In Allen County, Ky., detailed structural work done to the south of
Scottsville shows that in the area thus mapped the best production comes
from the northwest or west side of small structural domes, with closures
of about 20 ft., but where the dome has a very steep dip on the north or
northwest side, with gentle dips to the south, the production is obtained
on the south and southwest sides. Such production is always less than
the production from the northwest sides of Allen County domes. In
small wells that are shot, the production often drops off four-fifths after
the first two or three days. In several cases, wells that have come in
producing salt water change to oil after about two weeks pumping, and
make average producers. No fresh water is encountered in the Allen
County wells below the Chattanooga black shale. The average produc-
tion in this section is probably not more than 5 bbl. per pumping well.

STUAKT ST. CLAIR, Bowling Green, Ky. (written discussion).
Doctor Glenn's paper is interesting as an historical resum of the oil de-
velopment in these states, the former of which has come into prominence
during the past few years, producing, in 1919, approximately 8,000,000
bbl. of high-grade oil.

The writer had hoped that Doctor Glenn would give more detailed
data on the accumulation of oil in the Onondaga limestone, as that forma-
tion furnishes about 96 per cent, of the oil production of Kentucky. If
he had, in his discussion of the eastern part of the state, he would have
noticed that his statement that oil has migrated westward up the slope
of the rocks which rise from the great Appalachian trough until arrested
by an anticline with a northeast-southeast axis, would need some modifica-
tion or further explanation. Between the Appalachian trough and the
Irvine District, the latter comprising the oil fields of Lee, Estill, Powell,
and Wolfe Counties, there are a number of well-defined anticlinal struc-
tures that have been drilled upon with unsuccessful results. The Onon-
daga formation does not have a continuous bed of such porosity as would

138 OIL FIELDS OF KENTUCKY AND TENNESSEE

be needed for migration of oil, except within a restricted distance from
its outcrop and from the Irvine fault. Therefore, migration of oil in
this formation took place only over a short distance. As explained
by the writer in a paper 2 on the Irvine Oil District, the greater part of
the porosity in certain beds of the Onondaga from which oil is produced
is caused by solution by circulating meteoric water which has entered at
the outcrop and along fault planes. It is this theory that explains the
position and structural relations of the prolific Big Sinking Creek pool
of Lee County.

In view of what has been said, Doctor Glenn's statement that water
usually follows the oil in the Onondaga rather closely may need partial
revision. It is true that wherever there is oil in commercial quantities
there is also water, for water has in most cases caused the porosity in the
rock in which the oil has accumulated. However, there are areas where
there are very small wells of doubtful commercial value, the oil having
accumulated in the Onondaga where there may have been a little porosity
induced by recrystallization or partial dolomitization, where there is a
total absence of water. Outside of a restricted distance from the outcrop
of the Onondaga or from major faults, wells drilled on anticlines or in
synclines show a general absence of both oil and water.

How far the thought developed by the writer, in his paper men-
tioned above, showing the relation between the area affected by
circulation of meteoric water and oil accumulation in the Onondaga
limestone in Kentucky can be applied to other fields where the oil pro-
duction is from a porous limestone, cannot be stated, but he hoped that
the idea advanced might be used with additions or modifications in
helping to explain accumulation problems in other limestone fields.

Two minor corrections should be made in Doctor Glenn's paper for
the benefit of those unfamiliar with the Kentucky fields. First, the
gravity of the oil for the Irvine field is given correctly but it should not
be thought to include the adjacent Big Sinking field. In the latter the
gravity is much higher, running from 38 to 42 Be. and the gasoline
content is exceptionally high. Second, the great bulk of the oil in
Kentucky is not carried by the Cumberland Pipe Line Co. at the present
time. In the fields of Lee and adjacent counties, the Cumberland runs
but little more than half the production; the balance is handled by six
other pipe line companies, chief among which are the Indian Refining,
Great Northern, and National Refining. In Allen County, the Indian
Refining handles nearly all the production, although recently two other
pipe lines have entered the field.

The writer fully agrees with Doctor Glenn in his outline of the areas
of Kentucky that contain possibilities for future production. In his

2 See p. 165.

DISCUSSION 139

opinion, even the Allen, Barren, and Warren County areas are about
outlined at the present time. In the western Kentucky coal field, de-
velopment will be slow, but something of importance may be opened in
the Chester or lower Mississippian sands. Kentucky cannot hope for a
second Big Sinking, which is the most important field in the history of
oil production in the state. The flush was taken from this pool in 1919
and the production for that year will mark the apex of the production
curve for the state. The decline in the curve will not be great for 1920,
but after this year the decline will be noticeable.

In Tennessee, aside from a probable few small pools along the High-
land Rim in the limestone underlying the Chattanooga black shale and
within a restricted distance from the outcrop of this limestone formation,
or from a major fault, and a possible few small pools in the coal-measure
area in the eastern part of the state, the oil possibilities, in the writer's
opinion, lie in certain areas within the Gulf Embayment province west
of Tennessee River.

140 OIL POSSIBILITIES IN NORTHERN ALABAMA

Oil Possibilities in Northern Alabama

BY DOUGLAS R. SEMMBS,* PH. D., UNIVERSITY, ALA.

(Lake Superior Meeting, August, 1920)

THE possible oil territory of Alabama can be readily divided into
two regions, the Paleozoic area of the north, and the Coastal Plain
province of Cretaceous and younger formations lying to the south.
This latter area has received much attention in the last few years and
has been described by a number of writers. 1 Although the possibilities
of the Cretaceous series have been much emphasized by recent writers,
the fact remains that the two, or possibly three, localities where oil or
gas have been found in anything like paying quantities are confined
to the area of Carboniferous rocks. Moreover, almost all of the oil
seeps and a good percentage of the gas seeps are confined to this area. 2

Topographically, as well as structurally, the Paleozoic area can be di-
vided into three rather well defined provinces: (1) The broad, open
Coosa Valley lying adjacent to the crystalline oldland, with compara-
tively little relief, except for occasional longitudinal ridges and rather
intense folding; (2) the plateau region of horizontal or gently warped
Pennsylvanian strata broken by occasional anticlinal valleys aligned
northeast and southwest, outliers of the Coosa Valley proper, in which
the older Paleozoic formations are exposed a region of much relief (200

* Associate Professor of Geology, University of Alabama.

Eugene A. Smith: Report on the Geology of the Coastal Plain of Alabama.
Geol. Survey of Alabama (1894).

Eugene A. Smith: Concerning Oil and Gas in Alabama. Circular 3, Geol.
Survey of Alabama (1917).

O. B. Hopkins: Oil and Gas Possibilities of the Hatchetigbee Anticline, Alabama.
U. S. Geol. Survey Bull 661 (1917) 281.

Dorsey Hager: Possible Oil and Gas Fields of the Cretaceous Beds of Alabama.
Trans. (1918) 59, 424.

J Among the more important references on northern Alabama are:

Henry McCalley: Report on the Valley Regions of Alabama. Part I. (Ten-
nessee Valley.) Geol. Survey of Alabama (1896).

M. 3. Munn: Reconnaissance Report on the Fayette Gas Field, Alabama. Geol.
Survey of Alabama Bull. 10 (1911).

jEugene A. Smith: Historical Sketch of Oil and Gas Development in Alabama.
Oil Trade Jnl (Apr., 1918) 9, 133.

DOUGLAS R. SEMMES

141

to 300 ft.) and thorough dissection, well wooded, and of little agricultural
importance; and (3) the Tennessee Valley region of horizontal or gently
warped Pennsylvanian and Mississippian strata, where the relief is not
so marked, the wooded area is less extensive, and the country is of more
importance agriculturally.

60 65

Cretaceous

Carboniferous

Isouolue Determined'

Devonian-Cambrian
Isouolue Inferred

H Igneous and
II Metamorphic

GEOLOGICAL MAP OF NORTHERN ALABAMA, SHOWING CARBON RATIOS.

STRATIGRAPHY

The following generalized section gives an approximate idea of the
thickness and lithologic character of the formations of the region as a
whole. The Carboniferous series, especially, shows lateral variations
of striking prominence, but certain horizons are persistent throughout
the area.

Of these formations the Carboniferous cover much the larger
part of the whole region, the Pennsylvanian, or Coal Measures,
forming the surface throughout large portions of Cullman, Winston,
Walker, Blount, Jefferson, and Tuscaloosa Counties, and the Mississip-

142

OIL POSSIBILITIES IN NORTHERN ALABAMA

STRATIGRAPHIC SECTION FOR NORTHERN ALABAMA

AGE

Pleistocene
Pliocene

Cretaceous

FORMATION
NAME

Lafayette

Tuscaloosa

Pennsylvanian Coal

measures

Upper Missis- Mountain
sippian limestone

Lower Missis- Fort Payne
sippian chert

THICKNESS LITHOLOQIC CHARACTER

AND SUBDIVISIONS

0- 50 Unconsolidated and semiconsoli-
dated gravels and sands. Red,
pinkish, maroon, and whitish
clays.

0-1000 Gravels, sands, and clays. Red to
gray or white. Non-marine.

200-2500 Shales, arenaceous shales, massive
sandstones, and conglomerates
near base. Basal conglomer-
ate, or Millstone grit. Coal
seams.

400- 900 Massive bluish crinoidal lime-
stone (Bangor limestone), over-
lying a series of coarse to
medium-grained sandstones with
alternating thinner beds of lime-
stones and shales. Thick, lo-
cally massive, brown sandstones
at base (Hartselle sandstone).

200- 500 Cherty limestone or limestones
with thin chert seams or layers
of nodules. Readily eroded,
valley-making formation (Tus-
cumbia limestone). This over-
lies a series of hard cherts
(Lauderdale chert), very re-
sistant to erosion and forming
prominent ridges.

0- 50 Black, highly bituminous shales
and locally thin sandstones and
bluish shales.

200- 400 Shales, limestones (Niagara), and
ferruginous sandstones and some
conglomerates. Iron ores.
Bluish, thin-bedded limestone (Pel-
ham or Chickamauga) with
coarse-grained siliceous layers,
Unconformity making excellent oil sands.

Sharply folded and faulted thick-
2000-3300 bedded crystalline dolomite with

chert seams, overlying 600 ft. of
thick-bedded non-cherty gray
crystalline dolomite.

1000-1500 Thin-bedded blue limestone and
gray and yellow shales.

pian forming the surface in Madison, Limestone, Lawrence, Lauderdale,
and Colbert Counties. To the west, the Carboniferous strata are over-
lapped by the Cretaceous, which in turn is covered in places by the
Lafayette, but throughout a large part of this Cretaceous area the under-

Devonian Black shale

Silurian
Ordovician

Clinton

Unconformity (?)
Trenton
limestone 500-1000

Knox
dolomite

Cambrian Coosa shales

DOUGLAS R. SEMMES 143

lying Coal Measures are exposed along the courses of the principal
streams. The pre-Carboniferous rocks are only exposed in small
areas in the north, along the anticlinal valleys farther south, and in the
Coosa Valley.

Oil and Gas Horizons

The possible oil and gas horizons throughout the section are rather
numerous; many of these horizons have, locally, given very promising
shows. Owing to the striking lateral variations in lithologic character,
horizons that may at one point be promising have little or no possibilities
at another; this is especially true in the Carboniferous series.

Pennsylvanian Horizons

In the Fayette gas field in Fayette County, the wells encountered
the first shows at about 500 ft. (152 m.) below sea level, or at a depth of
from 850 to 950 ft. (259 to 289 m.). This sandstone, though giving good
shows of oil, proved of no value and the wells were continued 500 ft.
lower and there encountered the Fayette gas sand proper, a soft, white
sand of excellent quality. The best well of this group was estimated at
4,000,000 cu. ft. (112,000 cu. m.) per day. At other points, the sand was
found more tightly cemented and proved less productive. About 200
ft. below the Fayette sand a thick sandstone (250 ft.) was encountered,
which also gave gas shows and is locally known as the Second Gas sand.
Drilling has been continued 900 ft. below the Fayette sand and another
thick sandstone, containing salt water, was encountered near the bottom.
This sandstone has been correlated with the Pine sandstone member of
the Birmingham Folio, in which case the Fayette sand should be under-
lain by some 1000 ft. of shales and massive sandstones to the base of
the Pine sandstone, then 500 ft. of shales and shaly sandstones, and finally
500 ft. more or less of massive sandstones with conglomerates at the base
(Millstone grit). In other words, the Fayette gas sand should be about
2000 ft. above the base of the Pennsylvanian, if maximum thicknesses
were represented. Deep borings in the area have shown, however,
that the total thickness of the Pennsylvanian is not over 2500 ft., or
only about 1200 ft. of sediments underlie the Fayette sand. It should
be remembered, moreover, that in the Birmingham district the Boyles
sandstone (Pine sandstone) is found lying directly on the Bangor lime-
stones of Mississippian age, representing a hiatus of much over 2000 ft.
of sediments. The two basal sandstones of the Coal Measures, the Pine
sandstone and the Millstone grit, can be considered as possible oil hori-
zons, but owing to their great thickness, thorough cementation, and
massive character, as well as the fact that they have no adequate source
of oil below, the writer would not consider them horizons worthy in them-
selves of extensive testing.

144 OIL POSSIBILITIES IN NORTHERN ALABAMA

Mississippian Horizons

As early as 1865, wells were drilled in Lawrence County in the vicinity
of asphaltum and maltha showings in Mississippian strata, and the major-
ity of all such occurrences of bitumen, maltha, and asphaltum that have
been reported since are in these formations. In the Bangor limestone,
many such occurrences have been found and it is not unreasonable to
suppose that a sandy layer in this limestone might prove a paying oil
sand. Below the Bangor comes the Hartselle group of thick sandstones
and interbedded limestones. In Morgan, Lawrence, and Franklin
Counties, numerous seeps have been found in the Hartselle, and, in
many places, this group is found saturated with residual petroleum.
In many localities this sandstone is coarse-grained and friable, with a
large amount of pore space, which should make it an excellent oil sand;
but elsewhere it is fine-grained and highly cemented and has so little
pore space that it is improbable that it would prove a pay sand. Un-
fortunately, no good test has been made in this horizon as none of the
wells started in the Pennsylvanian has reached this depth, while those
started below the Pennsylvanian have usually commenced operations
on the Hartselle itself, or immediately above it. The Lower Mississip-
pian Tuscumbia limestone has given rather promising shows in certain
recent tests. In it are found sandy horizons that, according to the driller's
statement, make excellent oil sands.

Trenton Horizons

The only well that has struck oil in commercial quantities in Alabama
found it in the Trenton (Pelham) limestone. This horizon is, in the
opinion of the writer, the most favorable for commercial oil and gas to
be found in the northern part of the state. The Trenton series is com-
posed of thin-bedded bluish and shaly limestones, throughout which
there are horizons of coarse-grained, sandy limestones making good oil
sands. The well mentioned (Goyer No. 1), drilled in 1891, is located in
the southwest quarter of the southeast quarter of sec. 29, T. 7N, R 6W,
Lawrence County, and was not a geological location. A log of this well 3
is as follows:

FEET

36 Soil 10

35 Limestones; Bangor 290

34 Sandstones; first gas, in the upper part 35

33 Shales; a dark blue color 110

32 Limestone; of a pearly white, sulfuretted hydrogen gas was struck in this
rock at 55 ft. below its top and salt water at 53 ft. from its top; the salt

water on evaporation gave a good flavored salt 80

31 Limestone; of a light drab color 320

* McCalley's Tennessee Valley Report, 239.

DOUGLAS R. SEMMES 145

FEET
30 Limestone; impure, coming out as a coarse powder like corn meal and hence

called "corn-meal sand" 28

29 Shales; Devonian, black 32

28 Limestones; shaly 17

27 Limestones; blue 2

26 Shales; sandy and of a mottled (red and white) color 9

25 Limestone; it carries some little oil 422

24 A gritty calcareous sand, likely from 'an impure limestone 100

23 Limestone; blue 45

22 Limestone; coarse grained, the lower 5 ft. is an oil sand though it carries

no oil 9

21 Limestone; coarse grained, impure and siliceous, a good oil sand 20

20 Limestone; blue 261

19 Limestone; white 32

18 Limestone; blue with greenish specks 6

17 Limestone; white or cream colored 6

16 Limestone; blue 63

15 Limestone; bluish with a slight reddish tinge 26

14 Limestone; white 27

13 Limestone; gray with a slight reddish tinge 4

12 Limestone; white 4

11 Limestone; gray with a few reddish specks 3

10 Limestone; of a light gray color 49

9 Limestone; white 5

8 Limestone; of light gray and reddish specks 2

7 Limestone; of a brownish gray color 5

6 Limestone; white * 4

5 Limestone; of a grayish color with white and blue specks 7

4 Limestone; with large white specks that resemble pieces of fossils 4

3 A dark grayish powder with blue and white specks; it may be shale 5

2 Limestone; with white and light gray colors with reddish specks 22

1 Limestone; white 3

Of this above log, 35 is in the Bangor limestone, from 34 down into
32 is the Hartselle sandstone group; from 32 to 30 is the Tuscumbia
limestone and Lauderdale chert; 29 is the Devonian; and the rest is
Trenton.

The pay sand in this well was found 625 ft. (190 m.) below the De-
vonian. The well was estimated at 25 bbl., but owing to the collapse
of the casing and the letting in of salt water the well was lost. The oil
was of a light greenish color and had a specific gravity of 38.7 Be.

Knox Horizon

The Cambro-Ordovician Knox dolomite has occasionally given small
shows of gas; and since dolomitization with its attendant shrinkage
should indicate increase in pore space and in capacity as a reservoir,
this formation has been tested several times in the hope of its proving
productive. But, as the Knox lies unconformably below the Trenton
and where exposed shows a high degree of deformation, its possibilities
are so slight as to be unworthy of serious consideration.

VOL. LXV. 10.

146 OIL POSSIBILITIES IN NORTHERN ALABAMA

STRUCTURAL FEATURES

The Coosa Valley region and the adjacent outlying valleys are char-
acterized by a rather intense type of parallel folds, trending northeast
and southwest, with which are occasionally associated faults showing
displacements as great as 3000 ft. (914 m.). In many of these folds, the
Ordovician formations are exposed and, consequently, have no pos-
sibilities as oil traps. In addition to the northeastern series of prominent
Appalachian-type folds, there is a series of undulations running northwest
and southeast. These folds, or "waves" as they have been termed by
the earlier writers, are sometimes quite pronounced and show a reversal
of 100 ft. or more. At the intersection of these undulations quaquaversal
structures are formed, such as the Blount Springs dome, which should
make excellent oil traps if the oil horizons themselves are not exposed.
The intensity of the deformation of this area, however, is considered an
unfavorable factor in the development of valuable accumulations of oil.

In the Plateau region, running parallel to the Appalachian folds
farther east and south, there is a series of subsidiary undulations, which
can be traced out in the beds of the Coal Measures. In this area are
likewise developed the series of northwest-southeast waves, and at the
intersection of these two series more or less perfectly developed domes
are occasionally established. Unfortunately, the most favorable portion
of the Pennsylvanian area, the western part, is rather extensively covered
by the Lafayette gravels and the Cretaceous series, or by a mantle of
residual soil, which makes the locating of favorable structures a difficult
task; and after evidence of folding has been found, it is often impossible
to map the structures in detail.

In the Tennessee Valley region, especially in the area underlain by
the Mountain Limestone group (Morgan, Lawrence, Franklin, and Col-
bert Counties), the two series of undulations can be readily detected;
and owing to the character of the surface rock the structure can be
accurately mapped. Since the most favorable oil horizon, the Trenton,
occurs in this area at a depth of 1000 to 2000 ft., the area is considered
very favorable for future prospecting.

SIGNIFICANCE OF CARBON RATIOS OF COALS OF AREA

A recent paper by Fuller, 4 discussing the relation of the carbon ratios
of the Pennsylvanian coals to the oil fields of northern Texas, has interested
the writer in collecting and plotting the fixed carbon percentages of the
Pennsylvanian coals of northern Alabama. 6 In certain localities, a

4 Myron L. Fuller : Relation of Oil to Carbon Ratios of Pennsylvanian Coals in
North Texas. Econ. Geol. (1919) 14, 536.

6 For these analyses the writer is indebted to the publications of the U. S. Bureau
of Mines, to the Geological Survey of Alabama, and to R. S. Hodges, chemist of
the Geological Survey.

DOUGLAS E. SEMMES 147

sufficient number of analyses were obtainable to locate the isocarbs 6
definitely; in other areas, their location was largely inferred. On the
accompanying map, the direct relationship between the fixed carbon
and the amount of deformation is very apparent. Even such outlying
folds as the Sequatchie anticline have their definite effect upon the
percentage of fixed carbon in the coals mined along their flanks. The
degree of metamorphism attending this deformation has been shown by
David White 7 to be definitely related to the distribution and composition
of the oils found in the formations affected. When metamorphism has
reached such an extent that the fixed carbon in the coals, considered on a
basis of pure coal, has reached a percentage of 70, it is very improbable
that oil pools of commercial importance will be found. In the case of
northern Alabama, the writer believes that all areas where the fixed
carbon runs as high as 65 per cent, may be considered as unfavorable
territory and unworthy of extensive tests, until at least the areas of lower
percentages have been tested and oil found in paying quantities. An
examination of the accompanying map shows that the 65-per cent,
isocarb becomes definitely fixed near Huntsville and swings southward
and westward across Madison, Marshall, Cullman, and Blount Counties,
and along the northwestern line of Jefferson County, thence across
Tuscaloosa County, swinging around the southwestern end of Jones'
Valley anticline into Shelby County, thence southward again following
the crystalline area. Farther east, the 70-per cent, and the 75-per cent,
isocarbs swing around the areas of more intense folding and attendant
metamorphism. To the north and west of the 65-per cent, isocarb,
the 60-per cent, isocarb is less definitely located; and owing to the scarcity
of analyses of the coals of Marion and Franklin Counties, the location
of the 55-per cent, isocarb is in part inferred.

Favorable Areas

If we are to consider the relation between metamorphism and oil
distribution and composition as established, we are led to the conclusion
that all the Coosa Valley region and much of the Plateau Region is
unfavorable territory, and would expect in this area only small ac-
cumulations of light oil. West and north of the 65-per cent, isocarb
there should be better chances for larger accumulations, provided we have
the other necessary requirements of favorable section and structure.

The Pennsylvanian series shows a fairly favorable section, several
good sands, and good structure where it can be worked out. Most of the

6 The term " isocarb " has been adopted by David White, to signify a line drawn
through points of equal carbon ratio.

7 David White: Some Relations in Origin between Coal and Petroleum. Jnl.
Wash. Acad. Sci. (Mar. 16, 1915) 6, 189.

David White : Late Theories Regarding the Origin of Oil. Bull. Geol. Soc. Amer.
(1917) 28, 727.

148 OIL POSSIBILITIES IN NORTHERN ALABAMA

area underlain by the Coal Measures lies within the 65-per cent, isocarb;
to the west, the Coal Measures are covered by the Lafayette and
Cretaceous formations. In the Fayette district, which is near the 55-
per cent, isocarb, only gas was found in paying quantities, which would
indicate that the degree of metamorphism was still too great for
accumulation of oil. Considering, therefore, all evidence obtained so
far, the Pennsylvanian area is not considered favorable territory except
toward the western line of the state. In this area a hole drilled to 2500
or 3000 ft. would test the Hartselle sandstone as well as the Pennsylvanian
horizons.

To the north, the Pennsylvanian formations break off forming a pro-
nounced scarp facing the north. Passing down over this scarp, one comes
upon a fairly level plain underlain by the lower members of the Bangor
limestone. The upper, more massive members of this limestone form
the base of the scarp. Farther north, beyond the plain underlain
by the lower Bangor limestone, another scarp is formed by the Hartselle
sandstone, locally known as Little Mountain. Between these two scarps
there might be found favorable structure, where the Hartselle is suf-
ficiently covered to prove productive; this area is rather limited, however,
for which reason practically no tests have been made of the Mississippian
horizons.

By drilling at any point north of the Pennsylvanian scarp, the upper
Trenton horizons (Goyer horizon) would be encountered not more than
2000 ft. (609 m.) in depth. This would give a large territory comprising
most of Morgan, Lawrence, Colbert, and parts of Franklin and Lauder-
dale Counties, in which the type of structures commonly considered
as oil traps are fairly abundant, the degree of metamorphism is compara-
tively low, and the section is decidedly favorable. It is in this area, and
especially in Franklin, Colbert, and Lawrence Counties, that the writer
would suggest that future tests be made. Numerous anticlinal folds
can be found in the Hartselle sandstones and in places definite closure
can be worked out.

Past and Present Development

The extent and results of past development in northern Alabama have
been fully described by Doctor Smith in his historical sketch of develop-
ments already cited. The more important of these tests, with their
dates and producing horizons, are as follows:

1865. Watson wells, southeastern Lawrence County; good shows in two wells;
Trenton horizon.

1890. Newmarket well, Madison County; strong petroleum odor, but no sand;
Trenton horizon.

1891. Goyer wells, southeastern Lawrence County; one estimated at 25 bbl.
a day; Trenton horizon.

DOUGLAS R. SEMMES 149

1893. Allen wells, Florence, Lauderdale County; one dry, the other showed
small quantities of very light oil and some gas, well spoiled by shooting; Trenton
horizon.

1904-5. Huntsville and Hazel Green, Madison County; gas shows at both
localities; Trenton horizon.

1909. Fayette wells, Fayette County; one estimated at 4,000,000 cu. ft. of gas;
Pennsylvanian horizon.

1910-11. Shannon wells, Jasper, Walker County; 50,000 cu. ft. of gas, oil show;
Pennsylvanian horizon.

1911-12. Woodward Iron Co., Russellville, Franklin County; small gas show
in Knox dolomite (?).

1912. Bryan, Jefferson County; oil and gas show; Pennsylvanian horizon.

1916. Cordova, Walker County; good show, black residual oil; Pennsylvanian
horizon.

1917-18. Atwood well, Franklin County; gas indications; Pennsylvanian
horizon.

1917-18. Aldrich Dome wells, 6 mi. southeast of Birmingham, Jefferson County;
gas shows; Pennsylvanian horizon.

1918. Guin well, Lamar County; oil shows in two sands; Pennsylvanian horizon.

1919. Hobson well, Frankford, Franklin County; drilling at 1765 ft. (Dec.),
small oil and gas shows; Trenton horizon.

The evidence of the above tests strongly supports the carbon ratio
hypothesis, as all localities near the 65-per cent, isocarb showed gas
and only small shows of oil. The heavy oil found at Cordova (26.5 Be")
is an exception, but this was undoubtedly a pocket of residual oil, the
lighter volatile constituents of which had been driven off.

Future Prospecting

The area the writer considers most favorable for future testing is the
northwestern portion of the state, where the Trenton limestone would be
the producing horizon. Even this area is not without its disadvantages.
The degree of metamorphism increases not only near areas of deformation
but in depth in any locality. Therefore the degree of metamorphism
of the Ordovician formations, once covered to great depth by the Penn-
sylvanian series, may be much greater than is indicated by the Penn-
sylvanian coals, in which case commercial accumulations would be
improbable. Moreover, there is a possibility of an unconformity below
the Silurian. Nevertheless, considering the structure, the lithologic
character of the section, and the evidence of the carbon ratios of the
overlying Pennsylvanian coals, the area is undoubtedly worthy of further
tests, provided they be well located on carefully determined structure.
In addition to this area, the Coal Measures, where exposed in Winston,
Marion, and Fayette Counties, should be well worth testing, especially
where drilling is continued to sufficient depths to test the Hartselle and
the Trenton horizons.

150 OIL POSSIBILITIES IN NORTHERN ALABAMA

DISCUSSION

DAVID WHITE, Washington, D. C. Pessimism regarding the ca-
pacity of the Hartselle sandstone of Alabama should be discouraged.
The outcropping sandstone south of Tuscombia carries asphalt seepages
that are still fresh. In fact, the sandstone was once drilled near this
outcrop. The Hartselle is remarkably persistent throughout a great
area, and, in regions where the carbonization of the organic debris
has not progressed too far, this sandstone offers oil possibilities in favor-
able structures.

It is possible that the Carboniferous of western Alabama, beyond
the zone of too great carbonization, may contain oil deposits as important
as any to be found in the arches of the Coastal Plain formations.

MOWRY BATES, Tulsa, Okla. Last spring I examined diamond-drill
cores of Hartselle sandstone from holes drilled in nearly every section
of Alabama. Every core showed oil but it was thick and the sand
was so tight that it was impossible to move the oil. Under the microscope
no pore spaces could be found. None of these wells have shown oil in
appreciable amounts.

RESUME OF PENNSYLVANIA-NEW YORK OIL FIELD 151

Resume of Pennsylvania-New York Oil Field

BY ROSWELL H. JOHNSON, M. S., AND STIRLING HUNTLEY, PITTSBURGH, PA.

(New York Meeting, February, 1920)

PENNSYLVANIA will be remembered, as long as oil is produced, as the
cradle of the industry of petroleum in North America. It was on Oil
Creek, near Titusville, Venango Co., that Col. Edwin L. Drake, superin-
tendent for the Seneca Oil Co., brought in the first commercial oil well
on Aug. 28, 1859. Great difficulty was experienced in getting the well
down to the producing depth of 69 ft. (21 m.) with the spring-pole
system then in vogue for punching shallow water wells, so the novel
expedient of driving an iron tube through the surface clays and quicksand
was finally resorted to. The well had an initial yield of 25 bbl. a day
on the pump, but soon went off, though 2000 bbl. were produced by
the end of the year.

With the Drake well a success, a young industry sprang into being,
the rapid growth of which has been second to none in the country and
the value of whose product is only surpassed by that of coal. For
years the only producing territory, the Pennsylvania-New York field
attained its greatest production in 1891, when the bringing in of the Mc-
Donald pool, between Pittsburgh and the West Virginia line, gave a total
of over 33,000,000 bbl. At present the field, combined with West Vir-
ginia and southeast Ohio, gives 25,000,000 barrels.

GEOLOGY AND STRATIGRAPHY

In general, the Appalachian field is a huge geosyncline, the axis of
which runs roughly northeast-southwest, from north of the New York
state line south through Brookeville, Kittanning, Pittsburgh, Wash-
ington, through the southwest corner of the state of Pennsylvania into
West Virginia. Minor folding has accompanied or followed the
dominant fold of the field, and it is from these structures near the
Pennsylvania- West Virginia line and their influence on the accumulation
of oil and gas that I. C. White, state geologist of West Virginia, obtained
his evidence for anticlinal guidance of prospecting.

Many horizons in the geologic column of the field serve as reservoirs,
and there are several pools that have wells producing side by side from
different and widely vertically separated strata. The strata show a
promising succession of porous sand and conglomerate horizons alter-
nating with numerous gray and dark brown or black shales, admittedly

152 RSTJM OF PENNSYLVANIA-NEW YORK OIL FIELD

the ideal section. In southwestern Pennsylvania and northern West
Virginia, for the last few years, deep wells have been drilled in the hope
of revealing new deep gas reservoirs. It is interesting to note that the
last two wells have established deep drilling records for the world, the
last, the Hope Natural Gas Co., on the Lake farm, 12 mi. east of Fair-
mont, W. Va., having reached a depth of 7579 ft. (2311 m.)

As a rule, in the Pennsylvania-New York field, the dips in the pro-
ducing oil fields are very gentle with the exception of the Gaines pool,
producing from a fissured shale horizon, which has dips ranging up to
30. The sand bodies, though locally lenticular, are on the whole
fairly persistent. Indeed, with so many sand horizons, an operator
usually considers that he has a good chance in deeper drilling, even
though his principal sand is poor or absent.

Pennsylvania production runs from the top of the Conemaugh to
the base of the Chemung. The Murphy, Cow Run, and Dunkard sands
are in the Conemaugh; the Maxon appears in the Mauch Chunk shale;
and in the Pocono sandstone, below the Greenbrier limestone, are found
the Big Injun, Squaw, Papoose, Butler, Berea, Gantz, Fifty-foot, and
Hundred-foot sands. In the Catskill occur the Ninevah, Snee, Gordon,
Fourth, Fifth, and Sixth sands; and in the upper Chemung are the
Elizabeth, Warren, Speechley, Tiona, Bradford, Elk, and Kane sands.

In the latter part of 1919, a gas pool was developed south of Mc-
Keesport, Pa. where the dominant structure is the Murraysville anti-
cline, with a northeast-southwest axis. The Foster-Brendel No. 1 had
an extraordinarily high initial flow and unusually favorable marketing
conditions enabled it to yield over 50,000,000 cu. ft. the first day it was
controlled, which was about a week after its completion. The produc-
tion is from the Speechley sand at a little below 3000 ft. Lithology
here seems to play a more important part than structure. Dry holes
drilled along the axis of the structure revealed a dry tightly cemented
sand, which until recently condemned the territory.

The lateral limits of large production seem to be fairly well estab-
lished; and, due to the small area and the close spacing of the wells, it
is expected that the pool will have a short life. The rock pressure has
already been lowered from an estimated pressure of 1450 Ib. to 350 Ib.
and is declining at about 3^ Ib. a day.

The excitement over the one really large well has led to unjustifiable
claims that this is the world's largest gas field; it has also Jed to an
orgy of promotion and speculation. Except the Foster-Brendel lease,
the pool will show a net loss to the producers.

GRADE OF OIL

Nearly all the oil of the field is listed as the Pennsylvania grade and is
taken the world over as a criterion of high-grade crude oil. It is a light,

ROSWELL H. JOHNSON AND STIRLING HUNTLEY

153

greenish-colored oil with paraffine but no asphaltum. It varies around
44 Be*, and has a high gasoline content. It has always commanded a
premium over other grades, and its present price of $5.50 will keep alive
many old wells longer than seemed probable a few years ago, and also
noticeably encourage new production. Little difficulty is experienced
in marketing the oil and gas produced. A number of pipe lines collect
the runs of the field and carry them either to one of the several refineries
along the Allegheny and Ohio Rivers, or to one of the large pipe lines,
such as the Tidewater and the National Transit, which run down to
the huge refineries of the Atlantic seaboard.

TABLE 1. Natural Gas Production of Pennsylvania in 1916-1917

Year

Volume in
1000 Cu. Ft.

Average Price in
Cents per 1000
Cu. Ft.

Value

1916

130 483,705

18 78

$24 513 119

1917

133,397,206

21.53

28 716 492

TABLE 2. Natural Gas-gasoline Production of Pennsylvania in 1916-1917

Year

Number
of
Operators

Plants

Gasoline Produced

Estimated
Volume
of Gas
Treated,
1000 Cu. Ft.

Average
Yield of
Gasoline
per 1000
Cu. Ft.

Number

Daily
Capacity,
Gallons

Quantity
Gallons

Value

Price per
Gallon
Cents

1916
1917

167
287

195
251

46,487
59,164

9,714,926
13,826,250

$1,726,173
2,778,098

17.77
20.01

38,490,621
49,487,056

0.252
0.279

Great numbers of gas-gasoline plants have sprung up and are realizing
handsome returns from the utilization of casing-head gas as a source
of gasoline, before turning^over the dry gas to be used as a fuel. The
residual gas is taken up by public-utility corporations and marketed in
the nearby industrial centers both for manufacturing and domestic pur-
poses. Pennsylvania gas seldom has nitrogen in important amounts and
so gives an average heating value of about 1000 B.t.u.

The increasing scarcity of gas in this field has been a source of con-
siderable worry both to householders and to industries dependent on it
as a fuel. The scarcity has resulted^'n the gradual increase in price to
consumers and a careful redevelopment of old pools and a utilization of
former leakages and wastes. The recent deep drilling was the direct out-
come of this search for deeper 'gas to replace the gas from present
reservoirs, which are, of course, gradually becoming exhausted.

COSTS AND DRILLING

The cable-tool system was developed in this field to present standards
of efficiency. The ranks of drillers in Kansas and Oklahoma are com-

154 R^SUM OF PENNSYLVANIA-NEW YORK OIL FIELD

posed, to a great extent, of men whose apprenticeship was served in this
field. The cost of drilling has risen rapidly in this field, as in all others,
though perhaps not in so great a measure because of the proximity to the
iron and steel supply centers, and the comparatively greater supply of
labor at hand. The Drake well was 69 ft. deep ; the well that has recently
established a new world's record is 7579 ft. About 2000 ft. may be
taken as a fair average for the depth of present drilling. The average
cost of a producing well is about $16,000, although the variation is great.
The percentage of dry holes in 1918 has been estimated to be 22 per cent.

FUTURE POSSIBILITIES

In view of the long period of testing nearly all parts of the field since
its inception, there is little possibility of many new pools of considerable
extent or production being brought in from present producing horizons.
Max W. Ball estimates the present per cent, of exhaustion of the field at
69.5 per cent. One encouraging feature of the field, however, is the re-
markable evidence given by the decline curve of the Appalachian field.
The longevity is good, which is to be attributed mainly to the high price
which keeps the well alive for a long period after the rate of decline has
naturally become slow. Here, as elsewhere, close drilling gives the usual
sharp decline.

It is a remarkable fact that the land near the Drake discovery well
near Titusville, which was drilled in soon after the date of that well, is
still producing. The great richness of the casing-head gas permits some
leases in this field to be operated when it no longer pays to pump the wells.
We should get a much higher extraction. There is still the possibility
of the deep reservoirs of oil and gas, which was the goal of the recent
deep drilling. The disappointing results to date should not be taken too
seriously, in view of the fact that these wells were for the most part not
on the strongly marked domes, which should be chosen for such tests.

DISCUSSION

G. H. ASHLEY, Harrisburg, Pa. There are two or three things re-
garding Pennsylvania that are of interest. Mr. Johnson spoke of the
Gaines oil field which lies far east of the main oil belt. Another oil field,
very small, occurs near Latrobe, well east of the main belt, and over in
Somerset County there is a well that is reported to have yielded some oil.
These suggest the possibility of oil over all of the gas, or eastern, side of
the field. Again, in the southeast corner of this state, during the last
year or two, some oil has been found in seeps, which has raised the
question whether there may not be commercial oil in that section. The
matter is one we are still studying. We are not quite ready to say that

DISCUSSION 155

the oil is actually coming from its apparent source, that is, from the pre-
Cambrian rocks.

Some question has arisen as to the eastward extent of the gas fields
of the state. On the flank of the Chestnut Ridge anticline, there is a
little bench with a gas pool, and a little gas has been found in Cambria
County just east of the anticline. These facts would lead to the suppo-
sition that there might be gas on that anticline, but all efforts so far have
failed to show any. 1 The only explanation we can give for the failure
to find gas in that region is that the rock there is not favorable. There are
other places in the state where the structure and other conditions seem to
favor the presence of gas, but drilling finds none.

1 Since this was written, a drilling of the Peoples Gas Co., in the center of the
anticline where cut by Loyalhanna Creek, has struck 300,000 ft. of gas at 6822 ft.

156 GEOLOGY OP CEMENT OIL FIELD

Geology of Cement Oil Field

BY FREDERICK G. CLAPP, NEW YORK, N. Y.

(New York Meeting, February, 1920)

ALTHOUGH many oil fields have been, and still are being, discovered
in Oklahoma, the geology and structure of most of them have not become
familiar to the general public because of the delay in securing government
geological surveys and the reluctance of oil companies and other inter-
ested parties to give out their "inside information." Therefore, until
official surveys are available, it behooves us to publish geological results
as soon as possible. Fortunately the writer has been authorized by the
Cement Field Oil Co. to publish his data on the Cement field, Caddo
County, at this time.

LOCALITY AND DESCRIPTION

The Cement field is situated in the part of Oklahoma known generally
until recently, as "Healdton fields," and lies 60 mi. (96 km.) northwest
of the Healdton field proper. Like the Healdton field, it forms an ap-
proximate ellipse, trending northwest and southeast through the village
of Cement on the St. Louis-San Francisco Railroad, on which it is reached
in 2J hours from Oklahoma City.

In its geological structure, the field constitutes an anticline over 13
mi. (21 km.) long and from 1 to 3 mi. wide; the point of greatest width
being not far from its intersection by the above-named railroad. The
major axis trends north 75 west from the village of Cement; but east-
ward appears deflected (if field interpretations are correct) to about south
45 east. About 5 mi. south lies an approximately parallel syncline, which
may be conveniently called the Cyril syncline, the south and west bounda-
ries of which may be distant many miles, but forming a closed basin
south of the Cement anticline. The position of the offsetting synclinal
axis, which is believed to lie north and east of^Cement, has not been
discovered.

TOPOGRAPHY

In the southwest part of the state, nearly all maps of Oklahoma show
two mountain areas Arbuckle and Wichita which are conspicuous
geological and topographic landmarks. In addition, some maps show
a third, and smaller, range, named the Keechi Hills, in the vicinity of
Cement. These hills also form a conspicuous feature in the landscape;
but for some reason they have been neglected by geologists, and the

FREDERICK G. CLAPP 157

merest references to them have appeared in state and private reports.
In particular, they have been neglected until recently by oil geologists.
So prominent are Keechi Hills that they can be seen many miles away,
rising above the generally rolling agricultural surface in the form of mesa-
like and conical treeless masses 100 to 400 ft. (30 to 122 m.) above the
neighboring valleys. Perhaps their dwarfing by Wichita Mountains,
visible in the distance, is what has prevented their being studied and
tested for oil years ago; or, perhaps it is the presence of the sometimes
pure gypsum rock which caps the isolated mesas, and in one place caps
the main mass of Keechi Hills. The relief of the land surface in
Keechi Hills is about 500 ft., ranging from about 1150 ft. above sea-
level near the Little Washita River on the east, to 1630 ft. on the crest
of Keechi Hills.

HISTORY OF DEVELOPMENTS IN CEMENT FIELD

The first development took place, many years ago, in the village of
Cement, where a hole was sunk only a few hundred feet in depth and
abandoned. About 1916 a well was started on the Funk farm in section
6, township 5 north, range 8 west, 3 mi. (4.8 km.) east of Cement, and at
1415 ft. it discovered 500,000 cu. ft. (14,000 cu. m.) of gas and a showing
of oil; its total depth is 1685 ft. (513 m.) Shallow tests were also drilled
years ago in township 6 north, range 9 west, 3 mi. northeast of Cement;
and in section 21, township 5 north, range 8 west, 5 mi. southeast of Ce-
ment. The first real excitement, however, was caused, about 1917, by
the drilling of a well by the Oklahoma Star Oil Co., on the Kunzmiller
farm in the southwest quarter of section 32, township 6 north, range 9
west, 2 mi. northwest of Cement. At a depth of about 1700 ft., an un-
known quantity of oil was found which flowed into the tank. The pro-
duction is reported to have been 10 to 25 bbl. per day; but we have no
definite information on the subject, except that it still flowed slightly
when first visited by the writer in the fall of 1917. The main point of
interest is that the oil was found in a comparatively shallow sand of
Permian age, 800 ft. or more above the Fortuna, or next important group
of sands.

In September, 1917, Fortuna Oil Co. completed a gas well at a depth
of 2340 ft. and an initial production of 35,000,000 cu. ft. of gas per day, on
the Thomas farm in the southwest corner of section 31, township 6 north,
range 9 west, 3 mi. west of Cement and 1% mi. west of the Oklahoma
Star well. In 1918, the first weU of Prosperity Oil & Gas Co., in the
southeast quarter of section 5, township 5 north, range 9 west, was drilled
into the same sand at a depth of 2345 ft. and obtained a flow of oil, which
has been variously estimated from 50 to 150 bbl. per day; but the well
was badly handled and was thereafter continued in an effort to reach the
deeper sands. The first well of Gorton Oil & Refining Co., in section 2,

158 GEOLOGY OF CEMENT OIL FIELD

township 5 north, range 9 west was completed in 1918, having an esti-
mated capacity of 15,000,000 cu. ft. of gas per day. The second well of
the Gorton Oil & Refining Co., known as the " Betty G," was completed
later the same year in the northwest quarter of section 32, township 6
north, range 9 west; and while it has flowed oiJ, its production is not known,
because it has not been thoroughly cleaned out, but it was reported to be
good oil well. Fortuna No. 2 well, situated in the northwest quarter
of section 6, township 5 north, range 9 west was completed in December,
1918, with an initial production reported at 150 bbl. per day. The oil
is from the same sand as the gas in Fortuna No. 1, 1 mi. to the north. A
few days later the first well of Gladstone Oil & Refining Co. in southeast
quarter of section 31, township 6 north, range 9 west was finished, with
a reported initial production of 90 bbl. per day. Since that time three
other oil wells have been drilled along the north flank of the anticline, and
two near its center. Three wells are now being drilled or about to be
drilled to deeper sand. About sixty derricks stand in the field at the
time this paper is printed.

The well of the Cement Field Oil Co. on the site of the old Oklahoma
Star well, bought out by the aforesaid company, was only a small gas
well, as was the well of Hill Petroleum Corpn. in the southeast corner
of section 33. Fortuna No. 3, in section 35, township 6 north ; range 10
west, missed the sand but is drilling deeper; while Fortuna No. 4, in
the center of section 6, township 5 north, range 9 west, only had a showing
and is likewise preparing to drill deeper. These facts indicate consider-
able irregularity in the group of sands. Several wells are now being
drilled.

STRATIGEAPHY

The formations at the surface appear to be entirely of Permian age,
being designated technically as the Enid, Elaine and Woodward forma-
tions. The vertical section of the outcropping beds covers a stratigraphic
range of about 300 ft. (91 m.). In this section, two members demand
principal consideration; the Whitehorse sandstone and the Cyril
gypsum bed.

CYRIL GYPSUM BED

The most persistent formation in the field is the Cyril gypsum, which
ranges from 20 to 80 ft. (6 to 24 m.) in thickness. It is believed to under-
lie the Whitehorse sandstone of northern Oklahoma and here overlies
a great mass of generally gray sandstones that m'ght be supposed to be
Pennsylvanian, but which are nevertheless Permian in age. In southern
Caddo County, this gypsum bed is thought to be practically synony-
mous with the Blaine formation. There is no sign of division into three
gypsum beds as in central Oklahoma.

FREDERICK G. CLAPP 159

FORMATIONS OVERLYING THE CYRIL GYPSUM

The strata directly overlying the principal gypsum bed are classified
as Whitehorse sandstone of the Woodward formation, the intermediate
Dog Creek shales of the Oklahoma Geological Survey being generally
absent. Quite outside the limits of the field, however, are great masses of
red shale which may belong in the overlying Greer formation.

The best sections of the uppermost strata are visible south of Cyril
and on the north slopes of Keechi Hills, where deeply cut ravines inter-
sect the surface and expose the beds throughout a thickness of more than
100 ft. These are found to be mainly red sandstones and red sandy shales,
regularly or irregularly stratified, that in some places north of Keechi
Hills are so confused with recent dune sands as to raise the question
whether they too may not have been wind-deposited.

In the vicinity of Wichita Mountains, strong winds are almost con-
stant and sometimes fill the air with such clouds of dust and sand as to
simulate a desert sand storm. In some sections these winds have piled
the sand into considerable hills; for instance, over considerable areas 5 to
10 mi. southeast of Cement and also 1 to 5 mi. north of that town, form-
ing a belt parallel with and north of Keechi Hills. In this belt these
generally prevalent southwest winds have piled up the sands so that few
rock exposures are now visible; and beyond the impression of a synclinal
or homoclinal slope, little can be learned. Just where the Permian sands
end and where the recent dune sands and sandstones begin in these
areas is hard to determine in most cases.

Overlying the red sandstones are great thicknesses of red shales and
shaley sandstones, such as constitute most of the Permian series of western
Oklahoma.

FORMATIONS UNDERLYING THE CYRIL GYPSUM

The Enid formation is a name applied by the Oklahoma Geological
Survey to the lowermost 1500 ft. (457 m.) of Permian red beds up to the
base of the lowest heavy gypsum; therefore, in the Cement field, it in-
cludes all strata up to the base of the Cyril gypsum. So far as the Cement
field proper is concerned, the Enid consists of massive gray sandstones
of great hardness and persistence with overlying red sandstones; but few
shales have been found. The base of the Permian series is thought to lie
about 2700 ft. from the surface but some geologists place it at 1700 ft.
Beyond the east end of the field, a gypsum bed, generally only about 2 ft.
thick, outcrops in a few places; and gypsiferous sandstones occur in the
Enid formation in many localities.

GEOLOGICAL STRUCTURE

The geological structure of the Cement field is better known and more
easily determinable than that of any other known dome in the Permian
series. Only at its east end is there any considerable difference of opin-

160

GEOLOGY OF CEMENT OIL FIELD

ion as to details. It is an excellent anticline, or elongated double dome,
on which the zone of closure appears to be approximately 13 mi. (21 km.)
long and from lj^ to 3 mi. wide. The Cyril gypsum bed, on the basis
of which the structure contour lines of the accompanying map are drawn,
rises from the center of the Cyril syncline, 1 mi. south of Cyril, at an
elevation of less than 1350 ft., to an eroded position of more than 1650 ft.
above the east end of [the main Keechi Hills, 3J mi._north of Cyril.

R IOW

R9W

R 8 W

OILINWCLL LESS THHUtMfttTOU?

SHOHOF6ASINWELL LCSS THAN 2000 FEET DEEP
DRY HOLE I ESS THAN ZOOO FEET DEEP

OIL WELL IH2WO-FEETOKHJP OF SANDS

LAKE GAS WELL IN i300-Ff.F.TGPOUP OF SANDS
SMALL MS WELL IN Z300-FECT GROUP OF SANDS

O WELLS DP/LL/NO Off RIO BUIL T

OW IMP-FEET CROUP OF SA

s wan

PELO

MAP OF CEMENT OIL FIELDS

Ccrdc/o County, Oklahoma.

RIOW

R9 W

R8W

FIG. 1. GEOLOGICAL STRUCTURE'AND DISTRIBUTION OP WELLS IN CEMENT FIELD.
CONTOUR LINES ARE ON THE BASIS OF THE CYRIL GYPSUM BED. CONTOUR INTERVAL
50 FEET.

Descending the north side of the anticline, the gypsum drops below 1400
ft. (426 m.) in a distance of 2 mi. (3 km.) . West the axis plunges to about
1450 ft., 6 mi. north-northwest of the apex, and to 1300 ft. on its eastern
end; the amplitude of closure is apparently about 200 feet. Although
the main apex of the anticline is situated 3J^ mi. west of Cement, a
subsidiary dome with an apex above 1550 ft. centers 1 mi. east of that
village.

In the eastern end of the anticline, the horizon of the main gypsum
bed appears to descend to below 1300 ft., and northeast it drops below
1200 ft. between Ninnekah and Chickasha, and is believed to go much
deeper; but the exact correlations and amount of descent are disputed by
gome geologists.

COMPARISON WITH OTHER FIELDS

When comparing the geological structure of the Cement field with
that of other fields in southern Oklahoma, we must acknowledge that

FREDERICK G. CLAPP 161

its prospects appear excellent. So far as known it appears to be more
symmetrical than the Healdton field; but a buried mountain range may
just as naturally exist beneath the Cement field as at Healdton. The
general trend of the Cement field corresponds with that of the Healdton,
Burkburnett, Fox, Two-Four, Velma, Loco, and other less thoroughly
developed fields. While the general geological structure and attitude of
the formations are rather similar to those in the Kilgore field, which is
being developed in the extreme southeastern corner of Grady County and
in the adjacent edge of Stephens County, the trend of the Kilgore field
is, however, north and south, in contradistinction tojfchat of the Cement
field, which is nearly east and west. &tf

Correlations with the Duncan, Healdton, Loco, Wheeler, and other
southern Oklahoma and northern Texas fields are difficult; but we have
some data, and estimate that the Fortuna or principal producing group
of sands may be identical ^with the principal gas sand of the Graham-
Fox field. On this basis we might expect the deep new sands of that field
at about 3400 ft.; but in the only deep well in the Cement field it has not
been struck at that depth.

ATTEMPTED PREDICTIONS RELATIVE TO POSITIONS OP DEEP SANDS

In connection with studies made in Carter, Stephens, and adjoining
counties, the writer has had occasion to collect, compile, and plot many
well logs. Since these logs, when compared carefully with those in the
Cement, Kilgore, Fox, Graham, and Walters fields, give certain light on
geological conditions previously unknown and since this information
may be of value in the Cement field, it is given herewith.

The wells referred to as being the deepest or nearly deepest in their
respective fields are Prosperity No. 1 in Cement field, Magnolia No. 1
in Walters field, a well of the Kirk Oil Co. (which produced 36,000,000
cu. ft. per day of gas) in Graham field, and Pierce No. 2 of the Oklahoma-
Fox Oil Co. in the so-called Oklahoma-Fox field. These wells will be
referred to here as the Prosperity, Magnolia, Graham and Oklahoma-
Fox wells, respectively. Many logs of the Cement Oklahoma-Fox
fields and of the Santa Fe No. 1 of the Kilgore field have also been studied
in attempting correlations.

It must be acknowledged that the results are far from satisfactory,
on account of the variable nature of the red-bed formations, the uncon-
formity at the top of the Pennsylvanian series, and the personal equa-
tion in the case of records kept by different drillers with differing degrees
of care. There are, however, several sandstones, limestones, and shale
beds of enough persistence and definite characteristics that some sort of
correlations have been arrived at which, although not positive, are definite
enough to give certain ideas in the nature of predictions. The informa-

VOL. LXV. 11.

162 GEOLOGY OF CEMENT OIL FIELD

tion given should be accepted in this spirit, rather than as an absolutely
certain exposition of what will be found by deeper drilling.

First, it is barely possible that the Prosperity and Fortuna No. 5 wells
of Cement field passed through the horizon of the Magnolia 2150-ft.
sand of the Duncan field at about 2550 ft. without finding it. It is
much more probable, however, that the horizon of the Magnolia sand was
passed in the Prosperity well at about 2700 ft.

In the early days of the development of Cement field, we had no basis
by which to predict the position of the top of the Pennsylvanian series of
rocks or the position of the Healdton group of sands, because the records
of wells in the Healdton field were too discordant and the unconformities
of the buried "Healdton Hills" are too enormous to allow of deep-lying
correlations. Now, however, we have the log of Pierce Nos. 1 and 2 of
Oklahoma-Fox Oil Co. in section 7, township 2 south, range 2 west in
northern Carter County. These wells have gone to a greater depth than
others in the region, the producing sands being apparently about 1000ft.
below the producing sands in the Graham and Fox gas fields. One of
these deep sands has produced over 100 bbl. per day of oil into the pipe
line. The oil is of low grade but will presumably be lighter in fields
farther from the Arbuckle Mountains. The sand is a thick one and is
considered as about the stratigraphic position of the best oil sands in that
part of Oklahoma. At least three possibilities exist :

1. The Fortuna sand of the Cement field may have been penetrated
at about 600 ft. (182 m.) in the Graham field and missed entirely in the
Oklahoma-Fox field. In this case the Magnolia sand exists at about
1000 ft. at Graham. Then the horizon of the Graham gas sand (1480
ft.) should lie at about 3200 ft. in the Cement field, and the Oklahoma-
Fox sands at about 4200 ft.

2. The Fortuna sand may lie at 1000 ft. (304 m.) at Graham, and have
been missed in the Oklahoma-Fox wells. In this case the Magnolia
sand is the same as the Graham gas sand (1480 ft.) and probably the same
as the 1540-ft. sand in the Oklahoma-Fox wells. Then the Oklahoma-
Fox deep sands will be found presumably at about 3200 ft. in the
Magnolia well and about 3700 ft. in the Cement field.

3. The Fortuna sand may be equivalent to the big gas sand in the
Graham and Fox fields (1480 ft.) and to the 1540-ft. sand in the Okla-
homa-Fox wells. In this case, the Magnolia sand was missed around
1900 ft. in the last-mentioned wells, and the horizon of the Oklahoma-
Fox deep sands may be expected at about 3400 ft. in the Cement field.
This depth has now been passed by Fortuna No. 3 well in shale.

Whichever hypothesis is correct, there seems no possibility of finding
the Healdton or Oklahoma-Fox sands at Cement at less than 3400 ft.,
and they may be as deep as 4200 ft. The Oklahoma-Fox sands are con-
sidered as constituting a part of the "Healdton group," which are often

FREDERICK G. CLAPP 163

referred to informally but do not correlate satisfactorily in records of
wells in the Healdton field, on account of considerable unconformities
existing there.

These attempted correlations open a wide field for thought and con-
sideration. Our next starting point must be that the Magnolia sand of
the Duncan field appears to be at about the top of the Pennsylvania
series (bottom of the Permian "Red Beds") above which it is not usual
to expect oil in large quantity. In the great fields of Wichita County,
Tex., and to some extent in the Healdton field, large producers were found
in sands above this horizon; but these were, and are generally, believed to
be seepages from lower sands. Because the red beds are not capable of
having originated oil in themselves, geologists generally agree that oil
contained in them has risen from formations of the Pennsylvanian series.
This is the main reason for confidence that the main sands at Cement lie
below anything yet encountered.

Operators in Cement field should not allow themselves to become dis-
couraged over the outlook; they should bear in mind the following facts:

1. Since large gas wells and excellent showings of oil have been found
both at Cement and Kilgore in sands of the Permian series, which are not
normally oil bearing, we may expect something better in deeper sands
lying in the Pennsylvanian series.

2. It will not be necessary to go to the full 3200 or 4200 ft. throughout
the Cement field, as several sands are generally present in the Permian
and Pennsylvanian and some of these are productive at shallower depths.

3. It is decidedly possible that the Fortuna group of sands may be
more productive than usual somewhere in the field, as is the case with
Permian sands in the Healdton and Wichita County fields.

4. The finding of still shallower sands in the so-called Two-Four field
in western Carter County and southeastern Stephens County proves that
the sands of the Permian formations are very irregular, and some of these
lenticular sands may hold oil somewhere in the Cement field.

5. It is possible, and even probable, that the Keechi Hills, which are
coincident with the Cement field, overlie a buried mountain range, as
the Healdton field overlies the buried "Healdton Hills." In such case
the conditions at a depth generally become irregular and unusual
and numerous new sands occur, expanding the field laterally in these
"stray" sands.

6. Deep drilling will not be a permanent obstacle to the development
of the deep sands, as wells have been drilled economically in this
field by the rotary process. The cost of 4000-ft. wells in the future will
be less than the cost of existing wells. New wells started in the field
should be drilled with a rotary prepared to go to 4500 ft. if necessary.

The one fact that appears undoubted is that a considerable series of
oil sands should be expected below the Cement, Kilgore, and other fields
and some of these may be expected to produce oil at Cement.

164 GEOLOGY OF CEMENT OIL FIELD

Most of the statements here made apply also to the Kilgore field.
Although correlations and predictions are only of relative value, it is
believed that since the sands in these fields are deep and that both of
them are surrounded by deep synclines, the chances are good for large
productions as soon as the difficulties in deep drilling have been overcome.

CONCLUDING STATEMENTS

The foregoing is an exposition of conditions, developments, and prob-
abilities in Cement field according to the information and belief of the
writer. As in all fields in the course of development, it is not practicable
for any person other than a resident geologist to have all the facts at hand,
therefore some details may be in error. Especially is it thought some
geologists may have further light on the probabilities and predicted
depths of deeper sands.

IRVINE OIL DISTRICT, KENTUCKY 165

Irvine Oil District, Kentucky

BY STUART ST. CLAIB,* M. S., E. M., CHICAGO, ILL.
(Chicago Meeting, September, 1919)

IN VIEW of the great interest shown in the oil possibilities of Kentucky,
one is impressed with the paucity of reliable literature on the oil fields of
the state. A few brief reports by the Federal and State Geological
Surveys are about the only reliable data available. When the estimated
production figures, for 1918, are published by the U. S. Geological Survey,
they will show a revival of the oil industry in the Blue Grass State during
the past half decade. There will also be an increase in the production for
1919 and 1920, at least. Although as an oil-producing state Kentucky is
small, compared with some of the other oil states, the present production
and the area of undrilled proved territory is large enough to classify it as
one of the important oil states of the Union. This paper will be confined
to the Irvine District and the immediately adjoining areas which have
been prospected with varying success. The Corniferous limestone or
Irvine sand is the oil-producing formation in the area discussed.

In my divisional nomenclature, the Irvine District includes the Irvine
field, which extends from the town of Irvine eastward toward Campton;
the Big Sinking area, which joins and lies to the south of the eastern
part of the Irvine field; the Beattyville area, which lies to the north
and northeast of the town of that name and joins the Big Sinking area;
and the Ross Creek pool, which lies to the southwest of the big production
and across the Kentucky River. Except for the Ross Creek pool, the
main producing area is bounded on the east by the L. & E. R. R. and on the
west and south by the Irvine Branch of the L. & N. R. R. Winchester and
Lexington form the gateways and Torrent on the east, Irvine on the west,
and Beattyville on the south are the principle entrances to the main fields.
Evelyn, on the L. & N. R. R., south of Irvine, is the point of entrance to
the Ross Creek area.

GEOLOGY

The geology of the Irvine District is very simple. The rock forma-
tions with which the oil man should acquaint himself lie between the
lower measures of the Pennsylvanian sandstones and shales and the Devon-
ian or Corniferous limestone, or Irvine formation. Only a very brief
description of these formations will be given, as they have been described
fully by E. W. Shaw. 1

1 U. S. Geol. Survey Bull. 661d.

166 IRVINE OIL DISTRICT, KENTUCKY

Capping the hills, and forming a rim-rock over the eastern part of the
Irvine field, the Big Sinking, and Ross Creek areas, is a cliff-forming
sandstone above which are yellowish-gray and dark colored shales with
irregular sandstone and conglomerate members, and also some valuable
coal beds. Below are dark colored shales, with irregular thin sandstones,
with a thickness up to about 50 ft. (15.24 m.). Underlying these is the
Big Lime of the driller, or Newman or St. Louis limestone. It is typically
exposed along the L. & N. R. R. from a point south of Irvine nearly
to Heidelberg and in this district varies in thickness between 100 ft.
(30.48 m.) and 125 ft. (38.1 m.). The underlying Waverly formation is
composed chiefly of a bluish-green shale and has an average thickness of
about 450 ft. (137.16 m.). The Waverly and the underlying Black
Shale formation increase in thickness eastward and southeastward from
the Irvine field. The Berea sand is found in the lower part of the
Waverly formation in the eastern part of Kentucky and in adjoining oil
sections of West Virginia and Ohio. The Devonian, or Chattanooga,
black shale varies in thickness between 120 ft. (36.57 m.) and 170 ft.
(51.81 mj in the Irvine District. The base of the formation in most
places is a white shale, or fireclay as it is locally called, which varies up
to 20 ft. (6.09 m.) in thickness. In some localities, brown shale from a
few feet to 25 ft. (7.6 m.) in thickness underlies this and directly
overlies the Corniferous limestone, which is the Irvine sand of Kentucky.
This formation is a dolomitic limestone, sandy at a few irregular
strata, and contains chert in varying amounts. Porous beds, irregular
in their continuity, are the oil sands of the formation. The outcrop
at Irvine is brown in color and about 8 ft. (2.43 m.) thick, but eastward
the formation thickens rapidly, attaining about 100 ft. (30.48 m.) at the
eastern and southern edges of the main producing field. In Wolfe County,
near the Breathitt county line, the formation is approximately 175 ft.
(53.34 m.) thick. Underlying the Devonian are the Silurian shales and
interbedded limestones and the Ordovician limestones, one of which is,
perhaps, in part the equivalent of the Trenton.

The Irvine District is affected by the Cincinnati geanticline, which
extends in a general north-and-south direction, and the Chestnut Ridge
uplift, the axis of which crosses Kentucky in an east-and-west direction.
All beds dip away from the former structure, thereby making the general
dip in the Irvine District southeast. The Chestnut Ridge uplift has
been described, by Gardner, as extending from Pennsylvania through
West Virginia, Kentucky, and southern Illinois. This is a general dis-
turbance which has been of paramount importance in the formation of
some of the principal oil structures in this district. The northern boun-
dary of the Irvine field is marked by the Irvine fault, which is part
of the Chestnut Ridge disturbance. The general position of this fault-
ing is shown by Shaw. Most of the anticlines of the district closely

STUART ST. CLAIB 167

parallel the direction of this faulting. An eastward extension (includ-
ing the Ashley pool, the production near Zachariah, and to the east of
Torrent) is similar structurally to the Irvine field. The Camp ton ex-
tension was reported on by Munn. 2

From his observations, the writer is led to believe that there are
anticlinal structures of two ages in this part of Kentucky and very
probably in other parts also. The main structures apparently are the
younger, have a general east-and-west trend, and were formed by the
Chestnut Ridge uplift, which was probably completed in the Tertiary
period. The general trend of the older structures is north-and-south,
but the writer hesitates to venture a statement regarding their age as he
has not had the opportunity of studying all the facts that may bear upon
this problem. Some evidently antedate the last period of general base-
levelling of the region and are probably associated with the Cincinnati
uplift. These conclusions have been reached from a study of the rela-
tion between present topographic features and the structure. The
localization of some of the large producing areas may be due, in part, to
the intersection of the younger with the older structures.

OCCURRENCE OF OIL

Oil men who have had experience in a field where the oil is found in a
limestone will appreciate the eccentricities of sand condition encountered
in development work in Kentucky. In localities where the limestone is
hard and tightly cemented, the whole formation may be barren. Tight
sand conditions may be encountered in the center of an area with pro-
ducing wells on all sides and but a few hundred feet distant. Such a
condition is most unfortunate when encountered in a prospect well in un-
developed territory, as the operator may prematurely abandon the area.
Drilling has shown parts of the Corniferous limestone to be generally
porous over the area described here. Usually a porous bed of variable
thickness, from a few feet to 10 ft. (3.04 m.) or more, occurs directly
under a hard limestone cap-rock. Under favorable structural conditions,
this porous bed may be entirely filled with oil, and under less favorable
structure part or all of it may contain salt water. Over part of the Irvine
District only one pay sand is found but in some localities two or more
with a little, though in many wells without any, intervening salt water.
In some areas abundant salt water may be encountered under the cap-
rock, where the first pay sand should be found, and must be cased off
before lower pay sands can be drilled into. In fact, each locality pre-
sents varying conditions, so an intimate knowledge of the field should
be acquired in order that the operator may know how to handle
the problems confronting him in the development of his property.

2 M. J. Munn: U. S. Geol Survey Bull 471a.

168 IRVINE OIL DISTRICT, KENTUCKY

In general, the oil accumulation has taken place under anticlinal
conditions. In the producing areas, all folds and well-defined terrace
structures have been productive and salt-water wells have been the
result of drilling in the less favorable places. Exception may be taken
to this statement by some geologists when applied to the Big Sinking
area, but when other factors governing oil accumulation in this pool,
which factors will be mentioned later, are considered in association with
the anticlinal theory, this general statement will be found to cover the
case.

Only a generalized description of the Big Sinking area will be given
here, as a complete report on the oil pools of Lee County is being con-
templated. From certain deductions that will be given regarding this
field, the reader may appreciate the writer's reasons for having strongly
recommended the Big Sinking Creek area as early as the spring of 1917,
when the nearest drilling was some miles distant. At that time the
writer outlined on the map of a prominent Kentucky oil producer the
probable western boundary of the Sinking Creek area as being the divide
between Little Sinking Creek and Billy's Fork of Millers Creek, and the
probable eastern limit as the divide between Hell Creek and Walkers
Creek. So far, nothing of importance has been developed beyond
these bounds close enough to be classified as part of the Sinking Creek
area.

From what has been said regarding the anticlinal occurrence of oil
in the Irvine District, the reader has probably formed the opinion that
drilling on such structure outside of the present proved area should also
result in favorable strikes. However, experience has shown the oppo-
site results. Wells located near Beattyville, farther south in Owsley
County, in southern Lee County, in eastern Lee County north of Tallega,
in Breathitt, Wolfe, and Elliott counties, all located on well-defined
anticlinal structures, have struck only shows of oil. In the wells
closest to the producing fields, salt water was encountered; in those
farther away, the Corniferous limestone was hard and, in most cases,
practically dry.

BIG SINKING POOL

The structure of the Big Sinking area is not complicated. The re-
gional monoclinal dip, which is southeast, is crossed by several very low
folds, the axes of which are in a general east-and-west direction. The
resultant would be plunging anticlines with a general southeast-by-east
trend. Minor irregularities have produced terraces. In conjunction
with this type of structure, a broad low fold extends in a general north-
and-south direction and definitely outlines the western and eastern
limits of the Big Sinking pool. The axis of this fold roughly follows
Sinking Creek from Bald Rock Fork northward and the more pro-

STUART ST. GLAIR 169

ductive part of the pool is along the crest and on the southeast flank
of the fold with the most productive points determined by the east-and-
west folds.

The number of pay sands and their total thickness is variable in the
Big Sinking pool. As many as three sands, with a thickness of 40 ft.
(12.19 m.) have been reported but in some places 5 ft. (1.5 m.) will cover
all the actual pay sand encountered. Probably 15 to 20 ft. (4.57 to
6.09 m.) is an average for the more productive parts of the pool. In
general, the pay sand is very porous, although in short distances it may
tighten up materially. The best sand condition for quick recovery ap-
parently lies along the crest and the southeast flank of the north-and-
south fold. Westward from this fold, the sand changes rapidly. East-
ward, the change is more gradual, but with the increasing depth, due
to the regional dip, the sand becomes tighter and the pay is not so thick
nor uniform. However, wells in the tighter sand, although the produc-
tion is smaller pef day, will be longer lived than the wells in the porous
sand. The writer has estimated that from the very porous sand as much
as 1000 bbl., and in a few selected spots 1200 bbl., to the acre-foot of
actual pay sand will be produced. This amount will decrease to 500 bbl.
and probably as low as 200 bbl. to the acre-foot as the tighter sand areas
are approached.

The thickness of pay sand reported by various owners and lease men
is often misleading or in error. In most cases, the thickness of the true
pay sand is much less than it is thought to be when the well is being
drilled. Therefore, in making computations, the thickness of actual pay
sand should be carefully determined or the error in the calculated pro-
duction per acre will be large. This rough method should be used only
when no production data on the property or adjoining properties are
available from which decline and future-production curves can be
constructed.

The writer has been frequently asked why the oil is found, through-
out the Big Sinking area, on the higher and in the lower structural posi-
tions. It is quite evident that this condition is due to water pressure,
chiefly from the south and southeast, which is behind a sufficient body of
oil to cause the sand to be filled with oil over the entire area, thereby
forming one large pool in which nearly every location is proved. Salt
water will encroach upon the field from the south and the wells in that
part of the field and in the lower structural positions will be affected
first.

EXTENSION OF EASTERN FIELDS

The writer's personal experience in the Kentucky oil fields has led to
some deductions that may throw some light on the conditions described,
and which may be of value in prospecting the Corniferous limestone or

170 IRVINE OIL DISTRICT, KENTUCKY

Irvine sand in the eastern part of the state. The area under which the
Irvine sand will be productive of oil in commercial quantities is dependent
on three primary conditions, which are listed in the order of their impor-
tance: (1) Distance from the outcrop of the Irvine sand and from the
major faults. (2) Porous or non-porous character of the Corniferous
limestone. (3) Geologic structure. The writer will probably be criti-
cized for making the second condition less important than the first, but
in this field the porous or non-porous character of the oil formation is
dependent almost entirely on the distance from the outcrop, and espe-
cially from the major faults along which meteoric water is able to reach
the Corniferous limestone. It will be remembered that such a system of
faulting extends along the northern boundary of the Irvine field and on
the eastward occupying a similar relation to the Campton and Cannel
City fields. Water circulating through certain beds of the Corniferous
limestone has dissolved some of the mineral matter and left the rock
porous. The irregularity in the thicknesses of these porous beds indicates
that solution has taken place under non-uniform conditions of underground
circulation. The distance to which this circulation of meteoric water has
taken place from the outcrop or fault will mark the area of continuous
porous formation, which may contain either oil or salt water according
to structural conditions, and will mark the limit of the area that has been
unaffected by water circulation and in which the Corniferous limestone
will generally be tight and hard. The water in the Irvine sand, being
heavier than the oil, will occupy a position farthest down the regional
dip and will be dammed back by increasingly less porous beds. This
would form what we may term a monoclinal trough produced by dif-
ferential cementation of the limestone. Obviously then, a well drilled
on the crest of an anticline near the lower limit of this water area would
encounter water and not oil in the Irvine sand. The position of the oil
on the regional monocline would depend on the amount of water in the
trough. As stated before, it is the writer's belief that this pressure of
salt water to the south of the Big Sinking area, together with very porous
rock conditions underlying the Big Sinking area, is the explanation for
the unusually large concentration of oil in this field and may explain the
presence of oil-saturated sand strata in both higher and lower structural
positions in the Big Sinking pool. The pressure that causes flowing wells
is water pressure and gas pressure combined. Some water has been en-
countered at the southern edge of this pool although none has yet been
found in the main part of the pool.

Outside of the large area that has been affected by circulating waters,
there may be small areas where the Corniferous limestone has sufficient
porosity, either primary or through recrystallization or dolomitization,
or where minor faults have allowed some meteoric water to reach the
Corniferous limestone and dissolve some of it, thus producing porosity in

STUART ST. CLAIR

171

the rock, to allow small accumulations of oil. Chance drilling may
strike small pools of this class, which may be found on anticlines or in
lower structural positions. Tests, however, should be made on the most
favorable structures that can be found. No wells in this category of any
importance have yet been struck unless the Little Frozen Creek produc-
tion is extended beyond its present limits.

^ Paris

^^xingto

urchcad

(/^Raglcntl
^''Pool

S-~\ Frenchburg
i'-'.v'; Menefee

;' \t !f\,
3

i i^V ,^^\_^^^

T ^ . l\ ^( ^^//M'^u.^.Trrr I Torrent, '^' -ffe^

i^V^^^S^^^ c^

i^@^_^g\&<

^^,-f;l;\;^5 e

, J@ i ,,*wiy '^ // " ^

C^M S BcattyoitU L&aloney Oil Pool Litile ***

. ?$ ^roi^ ,/. .p ^c*.

S atitm
Cam}. C

P 0l hoM Creek
Lanhart jr,? p^l *s( Heidelbej-g

TJ_-I JS I

? --'

McKee

SOtu

'Little Frozen Creek

R JUVKSVII
* * VtaA*'

-i.^^>"--^

\^ .

^>i>n<2on

FlG. 1 OlL POOLS PRODUCING FROM THE IRVINE SAND.

Roughly, the probable line of separation of the possible productive
area and the non-productive area for the Corniferous limestone may be
drawn. Inside this line proper structural conditions are necessary for
commercial accumulations of oil. The line should run along the east
side of Ross Creek near the Lee County line to Kentucky River; then
eastward through Heidelberg, Beattyville, and Maloney; then north-
eastward, probably passing close to Holly Creek, Wolfe County; then
paralleling and closely following the Campton-Cannel City anticline.
This line is shown in Fig. 1 as the limit of the area of productive Corni-

172 IRVINE OIL DISTRICT, KENTUCKY

ferous limestone. The approximate position of the Irvine fault and the
outcrop of the Corniferous or Irvine sand are also shown together with
the oil and gas pools producing from the Irvine sand.

If the theory that the distance from the outcrop is of primary impor-
tance in determining whether the Corniferous limestone will be porous
enough for oil to accumulate in is correct, in areas where this formation is
present and of similar character to what it is in the Irvine District, and
if the overlying petroliferous black shale is present, under favorable
structural conditions there should be some accumulation of oil or gas;
provided the structure is far enough away from a fault of any magnitude,
which is on the down-dip side of the structure, to allow a sufficient area
from which accumulation may come. Reference to Fig. 1 will show that
the Menefee gas field, the Ragland oil field, and the Station Camp,
Ross Creek, Buck Creek, and Lanhart oil pools are not far from the out-
crop of the Irvine sand. These fields are located on structures and,
therefore, other small fields may be opened, under favorable structural
conditions, within a restricted distance from the outcrop of the Irvine
sand. 3

ECONOMIC CONDITIONS

For the past two years, Kentucky has enjoyed a great oil boom and
prices for acreage have gone sky-rocketing in certain parts of the state,
following each strike of, importance. Probably no area has had such a
quick advance in speculative prices in such a short time as the Big Sinking
area in Lee County. Two years ago, the Irvine field extending north-
eastward from the town of Irvine to Pilot was receiving nearly all the
attention of the oil men. Acreage along Big Sinking Creek was selling
for a very small bonus. With the opening of the Ashley pool, Pilot
district, the price of acreage began to advance and by the fall of 1917,
acreage in the Big Sinking area was selling from $50 60 $100 per acre.
During the year 1918, prices advanced to $2000 and $3000 per acre,
with extra royalties attached, in some cases. On such high-priced acre-
age, flowing wells are sometimes drilled, but the average initial produc-
tion will probably be between 100 and 300 bbl. per day. The writer
knows of a few wells that produced close to 1000 bbl. the first day and
another that flowed 24,000 bbl. in a little over four months. Although
these are the exceptions, there are many wells that are producing far
above the average.

The practice of additional royalty was started when there was no
valid reason for such action. It has kept many strong, conservative
companies out of the field and has brought in many operators who had

* Since this article was written, several oil wells have been drilled in southeastern
Menefee County on a well-defined structure.

STUART ST. GLAIR 173

the oil business to learn and some stock companies who had to get
production.

The Big Sinking area is a remarkable oil pool. The depths of the
wells vary from 800 to 1200 ft. (243.8 to 365.7 m.), dependent on the
topography. It has two, and in some places three, pay sands with an
aggregate thickness of 10 to 30 ft. (3.04 to 9.14 m.). Much of the pay
sand is very porous and the oil, in parts of the field, is under considerable
pressure. The gravity of the oil is around 40 Baum6 and the gasoline
content above 30 per cent. 4 The cost of drilling and equipping a well
varies from $3000 to $5000. These advantages, however, do not warrant
the payment of such high prices for acreage and additional royalty when
the average size of the initial production is considered. On account of
the porosity of the pay sands, the production will decline rapidly and the
average life of the wells in the Big Sinking field will not be long.

The Big Sinking pool is so young and in the older Irvine pool such poor
records of production were kept that it is difficult to get many accurate
figures from which depletion can be computed. Some leases that were
located on favorable geologic structure and had average sand conditions
were producing about 10 per cent, as much oil at the end of the first
year as they were producing at the point of maximum flush. Others
have declined considerably more where the wells were put too close
together. However, a few of the properties in the older Irvine field have
held up remarkably well, a fact that may be due to a thicker pay and
tighter sand, or inability of the pipe line to take all the oil. The oil sand
in the best parts of the Big Sinking pool is so porous that wells should not
be too close to one another. One well to five acres should be sufficient;
but on many leases the wells are 300 ft. (91.4 m.) apart and not infre-
quently there is one well to the acre. Under such conditions the wells
must decline rapidly, unless there is an unusually thick pay sand.

The writer has estimated that on properties where wells are properly
spaced and where there is an average thickness of pay sand, a well that is
continuously pumped would be producing about 10 per cent, of its initial
capacity at the end of a year. Where the pipe line does not take all the
oil produced, or where protracted shut-downs are experienced, these
estimates must be made proportional to the lengths of the unpumped
periods. Further, the average well, which will have an average thickness
of pay sand, in the very porous sand areas of the Big Sinking pool, that
is pumped regularly to its capacity will probably produce as much in the
first six months as during the remainder of its life. In tighter sand areas
it will probably take a year to produce half the oil under regular pumping
conditions, and to get the maximum recovery the wells should be spaced

4 The writer has been informed that some tests have shown a gravity of 42 Be".
and a gasoline content of 45 per cent.

174 IRVINE OIL DISTRICT, KENTUCKY

closer than in the porous-sand areas. What has been said of the indi-
vidual well may be applied collectively to a lease. Where new wells are
being drilled and production is being added all the time, the decline in the
producing wells is not as noticeable as when the property is fully devel-
oped. Production and decline records of wells and leases should be
carefully kept so that the owner may profit by the depletion allowance for
which he can claim exemption from taxation.

A company purchased a small lease that was producing and only
partly drilled up, paying at a specified rate per barrel of production that
amounted to approximately $30,000 per acre. With a very porous sand
and 20 ft. (6.09 m.) of pay sand, probably 15,000 to 20,000 bbl. per acre
should be recovered, if the pay is as thick as claimed. At the end of
about five months of regular pumping 7000 bbl. per acre was removed,
which is between one-half and one-third the calculated recoverable oil.
At the end of two or three years, the property will be practically exhausted.
A small profit will be shown on the investment if depletion is charged off
each year at a rate commensurate with the decline of the property. The
importance of correct estimates of depletion of properties in the Big Sink-
ing pool and in other pools of similar character in Kentucky cannot be
too forcibly impressed upon the operators.

The producing area north and northeast of Beattyville is but a south-
ern extension of the Big Sinking field and the remarks made are appli-
cable to it. Drilling is a little deeper and the wells are smaller, but
there is room for expansion of area. Care, however, should be taken in
drilling to avoid the salt water. The Ross Creek pool is the Big Sinking
on a small scale. It has been greatly overdrilled and must, necessarily,
have a short life. The area is rather limited but there are possibilities
for a small extension southward. Prospects for a few smaller areas of
production in this general region are good. 5 The Irvine field has been
quite fully exploited and only drilling up of proved territory remains.
This field has now been extended eastward several miles beyond Torrent,
the eastern entrance to the producing areas. Efforts to carry production
north of the fault in this field have failed.

Kentucky was a poor-man's field during the early stages of its recent
oil development and many have made comfortable fortunes. To get
acreage anywhere near the proved fields today requires capital. Wild-
cat acreage can be gotten cheap but the chances of success are commen-
surately lessened. There are opportunities for consolidation today that
did not exist a short time ago. Many local organizations could be
handled much more economically and efficiently if they were under larger

6 Since this article was written, in the fall of 1918, a pool has been opened on Buck
Creek, Estill Co., about 4 mi. (6.4 km.) north of Ross Creek. The area is one of the
prospects referred to and promises to furnish a number of small producing wells.

STUAKT ST. CLAIR 175

managements. Conservation is a pertinent question; mismanagement
and waste can be seen in many places and must cause injury to the field.
Considerable gas, which should be rich in gasoline, is allowed to go to
waste by the thousands of cubic feet per day. However, the field is
young and such conditions are remedied with time.

CONCLUSION

The object of this paper is to call attention to the probability that the
area of production from the Irvine sand in eastern Kentucky is a function
of the distance from the outcrop of the oil formation and from the major
faults. The results of many wells drilled to the south, southeast, and
east of the producing Irvine sand pools uphold this theory. However,
the writer does not wish to discourage prospecting in the deeper areas
as there are possibilities of opening up small, isolated pools. Prospecting
should also be carried on with a view to opening up production in sands
higher than the Corniferous limestone. Southeast and east of the Irvine
District, the Berea, the Big Injun, and sands higher than the Big Lime
may be found to contain oil in commercial quantities. In Knox, Floyd,
Magoffin, and Lawrence counties, there has been small production from
these higher sands for many years. A number of wells have been drilled
below the Corniferous limestone in the Irvine District, but no oil
formations were found. Sands are reported but oil shales apparently are
absent. The possibility of finding a deeper pay sand is not very promising.

176 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

Genetic Problems Affecting Search for New Oil Regions

BY DAVID WHITE,* WASHINGTON, D. C.
(New York Meeting, February, 1920)

IN THESE days, when detailed investigations of stratigraphy, structure,
and sand conditions so frequently result in the discovery of new oil fields,
and applause from oil companies and the public, geologists do well to
walk humbly, and punctiliously to admit that the geologic principles
controlling the distribution of oil and gas have as yet been discovered
only in part, and that what remains yet to be learned is probably vastly
more than what is already known. The few experiments already at-
tempted have been fragmentary, and somewhat desultory, and however
positive each of us may be with respect to certain theoretical conclusions,
many of the fundamental questions as to the origin and mode of occur-
rence of petroleum are subject to radical disagreement. Of the chemical
changes attending the generation of petroleum from organic matter,
little is actually known. Most of the postulated formulas are liable to
be misleading, through ignorance of essential factors. Open-minded-
ness is therefore a prime essential at the present stage of our science.
Nevertheless, adopting the hypothesis that oil originates in some man-
ner fundamentally connected with the organic theory, and in possible
departure from such open-mindedness, the writer will pay no attention to
the so-called inorganic theory, since every attempt to apply this theory
to the study of old oil fields, or to the discovery of new ones, affords
cumulative evidence of its inadequacy.

In this paper, some of the factors affecting the occurrence of petro-
leum that the writer believes worthy of consideration by the prospector
for oil in any new region will be discussed. Some of these, which are
less generally understood, will be considered somewhat in detail. Other
points, the significance of which cannot now be determined, require more
field study, and for that reason are here brought to the attention of the
field geologist. On the other hand, certain theoretical points which do not
bear especially on the oil possibilities of a new region will be given little
or no attention. The main topics that will be discussed are: (1) suffi-
ciency of carbonaceous detritus and residues in the oil-forming rocks; (2)
stage of carbonization of the organic matter in the oil-bearing formations;
(3) folding of the strata; (4) thickness of sedimentary formations; (5)
conditions of deposition.

* Chief Geologist, U. S. Geological Survey.

DAVID WHITE 177

SUFFICIENCY OF CARBONACEOUS DEBRIS AND RESIDUES IN
THE OIL-FORMING ROCKS

Most oil and gas geologists agree that in those formations in which oil
is found there must be sufficient organic matter genetically to account as
mother substance for the oil, which is believed to have escaped from its
mother rock into some suitable and accessible reservoir rock where it is
confined beneath impervious strata. However, very little seems to be
known as to the requisite quantity of mother substance or as to the maxi-
mum distance at which this substance may be situated from the reservoir.

Most geologists assume that this mother substance is carbonaceous,
but others hold that recognizable carbonaceous debris or visible residues
are not necessarily present. "Bituminous" or other carbonaceous shales
and milestones are almost invariably searched for because, seemingly
with good reason, such deposits are regarded as the principal materials
from which petroleum may be generated; certainly they are the rocks
from which oils nearest to typical petroleum may be artificially produced
by distillation. As shown by Orton and others, similar carbonaceous
matter adequate for supplying oil and gas may be found in most regions
disseminated through the rock or concentrated in certain layers; it is
present in ample amounts even in less distinctly carbonaceous shales and
limestones, and in some sandstones, and there seems no room for doubt
that oil in commercial amounts has been derived from such deposits.
Most dark limestones, sandstones, and shales, as well as ordinary black
shales, owe their dark tones to the presence of carbonaceous residues,
which are easily recognized under the microscope. Yet it remains to be
seen how much of such organic matter is requisite, as a minimum
probably, in reality, an average minimum. Circumstantial evidence
the conditions actually presented in certain oil fields seems to indicate
that the carbonaceous matter need compose but a very small percentage
of a supposed mother formation, if the matter is of the right sort, and if
other requisite conditions are fulfilled, and that a very great thickness of
the mother formation is not indispensable. In general, however, our
most productive oil deposits are found in districts containing formations
in which there is evidence of abundant life, with ample vegetal
matter. That only smaller productions are found in districts con-
taining little carbonaceous matter may prove to be a rule with
numerous exceptions.

In the search for oil in regions containing thick series of strata so
barren of carbonaceous matter as the "Red Beds" of New Mexico,
Arizona, and the northern Rocky Mountain States, or as the Jurassic of
Utah, southwestern Colorado, northern Arizona, and northwestern New
Mexico, or as the Newark formation of the Connecticut Valley and Penn-
sylvania, the question as to the quantity of organic matter appears, at the

VOL. LXV. 12.

178 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

present moment, to be somewhat insistent. As bearing in a practical
way on this problem, the demonstrated occurrence of oil in the Conemaugh
of the Appalachian Basin, in the Embar and associated beds of Wyoming,
in the "Red Beds" of north Texas and Oklahoma, and in small amounts
in red beds near Roswell, New Mex., may be cited. It must be admit-
ted, however, that the Conemaugh carries thin coals and carbonaceous
shales; that the Permian reds of Oklahoma and Texas contain rare beds of
coal and carbonaceous shales, usually of limited horizontal extent; and
that disseminated carbonaceous matter, in aggregate amounts larger
than at first thought, may be present in portions of the Embar and in
intercalated shales or sandstones in the "Red Beds" of New Mexico.
On the other hand, it is a question whether, in at least some of these
cases, the oil has not migrated upward from more carbonaceous beds in
relatively remote, underlying formations; or even whether the oil has
not migrated downward. The presence of other oil sands lying in more
richly carbonaceous formations, at different and sometimes great depths
beneath the "Red Beds" sands in the Appalachian Basin and in the Mid-
Continent field, lends weight to the supposition that in some cases the oil
has migrated upward instead of originating in the " Red Beds " themselves.
If the oil in the latter regions has ascended into the "Red Beds," deeper
sands should be tested in the possibly less forbidding shales beneath the
Embar of Wyoming and the Abo of New Mexico, and beds to the base
of the Percha will be explored in southern New Mexico, if the Percha is
present and not too greatly altered.

A. W. McCoy, who has had most excellent opportunities for studying
the composition of the beds penetrated by the drill in the Mid-Continent
field, points out 1 the presence of ample carbonaceous material, including
oil shale, intimately associated with the Bartlesville sand in northern
Oklahoma, and suggests that closer inspection will reveal the presence of
sufficient mother substance in close proximity to the oil sands in other
regions. The discovery, somewhere, of oil in a series of distinctly non-
carbonaceous "Red Beds," directly underlain by metamorphic rocks or
igneous masses, with no possible source in nearby unaltered sediments,
would have an important bearing on this problem, and should be recorded ;
drilling under such conditions, however, will probably be done with great
hesitation. The argument that oil in the above-mentioned "Red Beds"
has migrated downward suggests the inquiry whether the associated gas
also gravitated. Certainly, if oil has not been generated in beds which,
on casual view, appear to contain very little organic matter, the petro-
leum in some of our sands must have migrated across many hundred
feet of strata before finding hospitable storage in its present reservoirs.

l Jnl.Geol. (1919)27, 252.

DAVID WHITE 179

The term "organic matter" should be restricted to carbonaceous
debris and residues, as distinguished from non-carbonaceous mineral
deposits of organic origin, such as shells, diatoms, etc., which may now be
devoid of any associated hydrocarbons. Such mineral deposits do not,
I believe, serve as mother substance of oil, although, when porous, they
may offer excellent storage. In many, perhaps most cases, however, lime-
stones contain some matter that is strictly organic and may have been
mother substance. Impure, especially argillaceous, bituminous lime-
stones should well serve the purpose of mother rock, and have un-
doubtedly done so.

The question as to whether oil may not have been generated in the
biochemical stage at the time of the decay and deposition of the organ-
isms, such as mollusca or diatoms, as believed by Stuart and many other
oil geologists, is a debatable point germane to this subject, but will be
considered in connection with the influence of diastrophic movements.
The discovery of oil pools in a great thickness of strata actually barren
of carbonaceous or so-called bituminous matter, but containing lime-
stones largely of " organic" origin, and underlain by metamorphic or
igneous basements, would give force to this theory.

STAGE OF CARBONIZATION OF THE ORGANIC MATTER IN THE OIL-BEARING

FORMATIONS

A study of the incipient regional metamorphism of carbonaceous
deposits in the coal and oil fields of the United States and other countries
shows that no commercially important oil fields have yet been discovered
in any area where the fuel ratios of the coals, occurring in the formations in
which oil is sought or in overlying formations, exceeds 2.3. The progres-
sive devolatilization by which the coals in any region or formation have
been transformed from peats to lignites, bituminous coals, etc., and
finally to graphite, is the first indication of incipient metamorphism 2 of
the rocks of the area. The proximate analysis of the coal or coaly deposits,
as the writer has shown, 3 is a sort of "ultra-violet" method of observing
this initial stage of regional metamorphism of the ordinary type. Other
attending criteria include the stages of dehydration, consolidation or
lithification, development of jointing and cleavage, and, in due time,
schistosity and mineralization.

More observations and tests are necessary to fix more exactly the
stage of regional alteration beyond which commercial oil pools, though

2 In this transformation the mass of organic debris (coal or coaly matter) is altered
both in chemical composition and physical characters. In other words, technically,
it is genuine metamorphism.

3 Jnl Wash. Acad. Sci. (1915) 6; Bull Geol. Soc. Amer. (1917) 28, 727-734-

180 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

formerly present, will not have survived, but it is probable that the
limit falls, in general, slightly lower than the point at which coals of the
ordinary bituminous type show a fuel ratio of 2.2, or 68 per cent, of fixed
carbon in the pure coal; it may approach nearer the ratio of 2.0, or 66
per cent, fixed carbon. Coals verging toward the sapropolic type, such
as are believed by many to approach more closely the typical mother
substance of oil, are more fatty and accordingly richer in hydrogen and
lower in fixed carbon (pure coal basis) than the other types, until, in the
course of alteration by geologic processes, they approach the above limit,
when the volatile matter seems to disappear rapidly. At the semi-
bituminous stage (fuel ratio 3.0, fixed carbon 75 per cent.), their carboni-
zation is approximately on a parity with typical bituminous coal.

It is important that, in a new region under consideration as to oil
possibilities, every precaution be taken to ascertain whether the alteration
of the rocks, as indicated by the stage of carbonization of the carbonaceous
deposits, has not gone so far as to preclude the survival of oil in commer-
cial amounts. As I have shown in the papers already cited, drilling in
regions of greater metamorphism will find only gas or mere showings of
"white oil " approximately kerosene generally little more than samples,
and nowhere in commercial amount. This principle appears to be proved
by thousands of tests in the Appalachian field, in the Mid-Continent
region, and in other parts of the world.

Oil in commercial amounts should not be expected in the Devonian
of east-central and southeastern New York and eastern Pennsylvania;
in the Paleozoic regions of Georgia; in the Arkansas coal field; 4 nor in
those areas of northeastern Kentucky, of eastern Tennessee, of Alabama,
of the Paleozoic region in southeastern Oklahoma, and portions of New
Mexico, Colorado, Montana, Utah, and Washington, as well as of Penn-
sylvania, Maryland, Virginia and West Virginia, where the regional
carbonization has passed the stated limit. The Utica, Genessee,
Hudson, Ohio, Chattanooga, and Woodford shales are splendid de-
positories of mother substance, but it is futile to search for oil in the
associated "sands" in regions where the organic matter of these shales
is too far altered.

It is unfortunate that so little attention has been given to this factor
of control of the distribution of oil, and so little systematic effort has been
made to secure such evidence as might have been gained. Data are
needed, for example, as to the carbonization of the organic matter in the

4 Over 300 holes have been drilled in the Arkansas coal field with but a showing of
"white oil" in a single instance, although, as in Pennsylvania, West Virginia and
other areas, gas may be present in commercial amounts in anticlines, where the car-
bonization has progressed too far for the survival of oil pools. An asphaltic dyke at
Mena, in the altered region of Arkansas, has been anthracitized.

DAVID WHITE 181

Percha (Devonian) shale and the Magdalena limestone and Sandia
formations in portions of New Mexico, 5 for the information concerns not
only the probability of finding oil pools in or adjacent to these forma-
tions, but also the problem as to the source of oil that may be found in
the overlying Red Beds. It is known that the coals of the Mesa Verde,
in portions of the Trinidad, Crested Buttes, and Durango coal fields,
approach, if they do not pass, the fuel-ratio limit, but the boundaries of
the areas in which oil should not be expected in this or the underlying
formations have not been determined for lack of sufficient and properly
distributed coal analyses. The high probability that the abundant
organic debris in formations like the Mancos and Graneros, and the still
older formations beneath the Mesa Verde, have been still more altered
must not be overlooked in any search for oil deep below the coals in these
regions of relatively high carbonization.

Also, in the lower Saline River Valley, in southeastern Illinois, where
the carbonization advancing toward the south approaches the oil limit,
some uncertainty will attend exploration for oil in anticlines of the Miss-
issippian, Devonian, and Trenton, which furnish oil in other parts of
the state. The degree of carbonization of organic deposits in the exposed
beds, and the probably greater alteration of the underlying beds, deserve
further consideration, wherever the data are procurable, in the regions
of some of the anticlines located in the direction (southwest) of advancing
carbonization in Montana; and it should not be ignored in the vicinities
of the coal fields near Sunnyside, Utah, and in Washington and Oregon.

Disregarding contact metamorphism, which from the present stand-
point is unimportant, it is probable that regional alteration in much of
the Newark formation of the Atlantic States has advanced too far to
encourage the driller, even where the series has great thickness, contains
ample carbonaceous matter, and is not too closely folded. If found to be
not too far altered, it should, where sufficiently thick, be reviewed by the
oil geologist. Reliable information, if it can practicably be obtained,
is to be desired, as to the stage of alteration of the Upper Paleozoic
in portions of Montana, Utah, and Arizona, though it is possible that
in some areas inferences based only on cleavage, induration, incipient
schistosity, and mineralization (not contact alteration), can be drawn.
In many instances, valuable deductions may be based on distillation
tests of oil shales or other richly bituminous shales which, if far
devolatilized, will yield little oil, though containing much carbon.

In passing, it should be noted that: (a) local, slight variations of
carbonization are not to be ignored, for they are to be expected, especially

6 The coal of the lower Pennsylvania!! appears to be too far altered in the Pecos
Valley, about 10 miles above New Pecos, and samples from Bernalillo County cast
suspicion on the same formation in that county.

182 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

in closely folded and faulted areas; (6) in general, carbonization advances
downward, according to the law of Hilt, 8 so that the fuel ratios of coals in
underlying formations will, in most cases, be higher than in the exposed
formations, thus offering no hope of getting oil at greater depths where
the regional alteration of the exposed rocks is too great; (c) the carboni-
zation rule applies only to areas in which the alteration is regional, not
contact metamorphism ; (d) the fuel ratios are typically based on coals
or coaly deposits of the so-called bituminous group, and may be satis-
factorily determined in coaly streaks, in very earthy and bony coals,
and in shales containing great amounts of organic matter, though it is
not yet proved that they can be determined in shales carrying but small
percentages of carbonaceous matter. Attempts to determine the per-
centage of fixed carbon in the organic matter of ordinary carbonaceous
shales have not yet been wholly successful, but experiments are now in
progress with the object of learning the minimum of carbonaceous matter
that may be reliably subjected to proximate analysis in the average
carbonaceous shale. If methods can be devised for successfully ascer-
taining the fuel ratio in the organic matter of even moderately carbonace-
ous shales, criteria of the greatest value will be available to the driller.

As bearing upon the grade of oil that may be expected in a new
region, attention may again be called to the observation that, in general,
the oils in regions of relatively high, but not too high, carbonization are
characteristically of the highest grade, that is, of low gravity; while in
regions of less carbonization the oils average higher in gravity. Going
still further, as the writer has elsewhere pointed out, the oils found in
regions of low-rank coals, such as lignites (brown coals), are also character-
istically, though not without exception, lowest in rank, notwithstanding
the lack of satisfactory explanation of the fact, on what may at the present
moment be considered a reasonable chemical basis. The true explana-
tion may come from the thorough application of experimental physics
and physical chemistry to the oil problem.

The causes of carbonization (alteration) of the organic debris and resi-
dues in sedimentary formations have been more fully discussed in my
previous papers, but will be briefly reviewed in the following section.

FOLDING OF STRATA

Folding of the strata, or the development of structure, is almost
universally regarded as an essential feature of any oil region. The
migration and "gravitational" segregation of oil, gas, and water are
commonly supposed to be connected with the existence, if not
indeed with the origin, of folds, and in particular with minor local

U. S. Bureau of Mines Bull. 38 (1913), 125.

DAVID WHITE 183

anticlines and domes. Therefore, folding is always looked for and
analyzed in detail.

However, to what extent and through what processes folding operates
as a cause, or a means, or, on the other hand, whether it is to be regarded
only as an effect or a mere indication, is yet to be shown. Most of us
hold that folds facilitate the segregation and localize the distribution of
oil and gas pools, 7 and are therefore of great consequence in the search
for new oil fields; contrasted with this view, folding seems to be regarded
by some geologists mainly as an effect of questionable importance.

One of the most thoughtful advocates of the operation of folding as a
cause of the migration of oil and gas is Marcel R. Daly, 8 who starts with
the assumption that the oil already exists, presumably from the date of
deposition of the terrane, disseminated in the clays, sands, etc. in the
form of minute spherical globules between the mineral particles. Under
increasing loading by deposition of superincumbent strata, the argillace-
ous and organic deposits are compressed and the water, oil, and gas are
gradually squeezed out of the compacting deposits, moving in the direc-
tion of least resistance into the less compressible sandy beds and sand-
stones. Coalescence of the globules and concentration of the liquids
proceed en route. In the sandstone, separation of the water, oil, and
gas tend to go forward according to the size of the pore spaces, the water,
with its greater capillary tension, tending to occupy the fine-grained
portions and forcing the oil and gas into the larger voids. Horizontal
stresses of diastrophism, causing new and greater differential compression
of the beds, produce waves of unequal compression and, overcoming
friction, drive the water and hydrocarbons into the zones of less pressure,
some of which are the forerunners of anticlines as buckling proceeds,
the tops of the anticlines offering zones of least compression, while the
bottoms of the synclines are most squeezed.

The important point of Daly's presentation is the function of loading
and thrust pressure in causing the escape of the water and oil from its
matrix into the sands, and in overcoming capillary resistance to further
migration into reservoirs and anticlines. It is hoped that this paper will
bring partial support to some of Mr. Daly's conclusions.

In previous discussions 9 of the features common to the genesis of coal
and of oil, the writer has insistently pointed out that the evolution of each
is brought about through the common agency of dynamic forces mainly
horizontal stresses acting on loaded strata and causing the progressive

7 Preliminary compilations by K. C. Heald indicate that over 88 per cent, of the
anticlines and domes in the Osage Nation are oil-bearing, as compared with about
15 per cent, of the synclines.

8 Trans. (1916) 66, 733-753.

Jnl Wash. Acad. Sci. (1915) 6; U. S. Bureau of Mines Bull 38 (1913) 91;
Bull Geol. Soc. Amer. (1917) 28, 727.

184 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

devolatilization of the organic debris and residual products buried in the
sedimentary deposits. Both coal and oil are products of alteration, by
geologic processes, of organic matter not only similar, but, at least, in part,
identical in composition. Coal consists of the mass or stratum of rela-
tively pure organic debris, including the residual solid hydrocarbons
left in the process of transformation from peat, or its genetic
equivalent (deposited under different conditions), to graphite. Oil,
on the other hand, is a volatile product of this natural "distillation"
by the same agencies, of the organic debris and residues buried in
the sedimentary deposits.

The transformations or geochemical changes are intimately associated
with, if they are not actually caused by mainly horizontal stresses, under
loading, with consequent molecular displacement, and some incidentally
generated heat. The temperature developed during the process was
probably very moderate, and almost certainly was not great enough to
distil the organic matter at slight pressures. 10 There is generally but
little trace of alteration of the rock except progressive dehydration, com-
pression, and lithification in the earlier stages, with some sericitization;
the latter can, however, hardly be attributed to hydro thermal action, 11
since there is no evidence of the percolation of magmatic waters. De-
formation of crystals has not yet been observed, except in sands of regions
where the carbonization is approaching anthracitization, in which case a
change to quartzite, and some deformation of quartz grains, may be
noted, as well as occasional thin platy cleavage, probably representing
incipient schistosity. As the regional alteration approaches the gra-
phitic stage, mineralization and considerable deformation of the rock
grains, including pebbles, may locally be noted. In short, the trans-
formation of the organic debris and the concomitant changes in the sur-
rounding rock are such as are characteristic of the earliest phase of normal
regional metamorphism. The chemical reactions in the organic matter
are not yet convincingly explained. The processes are now in opera-
tion, though they are more energetic and efficient in regions and during
periods of dias trophic movement.

Experimental evidence strongly, but not conclusively, supporting

10 Observations by C. E. Van Orstrand, of the U. S. Geol. Survey, of temperatures
in several deep wells in the Northern Appalachian region indicate temperatures, at
the present time, of approximately 170 F. (77 C.) at depths of 7500 ft. (2286 m.),
the increase averaging 1 to 50 ft. in depth. [See Ohio Gas & Oil Men's Jnl (Sept.,
1919) 1, 22.] The temperature gradient is found to be steeper in other regions. Thus,
at a depth of 3000 ft. (914 m.) at Newkirk, Okla., it is 128.1 F. (53.5 C.) or 1 F. per
46 ft., while in the Ranger, Tex., field, at 3000 ft. the temperature was 134.9 F.
(57. 1 C. ) , the rate of increase being 1 to 45 ft. No doubt very much steeper gradients
will be found in regions of more recent movement.

11 Studies of the petrology of oil sands are now in progress by M I. Goldman, of
the U. S. Geol. Survey.

DAVID WHITE 185

the pressure theory of the origin of oil has recently been adduced 12 by
Alex. W. McCoy, geologist of the Empire Gas and Fuel Co. By means
of pressure on the ends of a cylinder of oil shale enclosed in a tube, the
walls of which were thinner in the central zone than at the ends, so as to
allow bulging, Mr. McCoy was able to induce flowage in the oil shale, and,
without causing an appreciable amount of heat, developed small globules
of oil in the shale which were visible with a hand lens. The material
used in the experiment was typical oil shale, capable of yielding 25 gal.
(94.6 1.) of oil to the ton, and having a crushing strength of about 3000 Ib.
per sq. in. (211 kg. per sq. cm.). No oil could be removed by solvents
prior to the experiment. From this and other experiments, Mr. McCoy
concludes: (1) that the solid bituminous material in the rocks is only
changed to petroleum by pressure in local areas of differential movement ;

(2) that "the accumulation of oil into commercial pools is accomplished
by capillary water; and this interchange only takes place in local areas
where the oil-soaked shale is in direct contact with the water of the res-
ervoir rock," such conditions being explainable either by joints or faults;

(3) that "some adjustment takes place" until the oil in the sand has
found the larger openings, where it remains indefinitely; (4) that "the
amount of oil in any field could have been derived from normal bitu-
minous shales in close proximity to the pay horizon;" (5) that areas of
maximum differential movement are in accord with anticlinal structures,
that the maximum sub-surface faulting is on the flanks and sides of the
anticlines, and that the best production runs in trends parallel to the
faulted zone. The most important part of Mr. McCoy's experiments,
as it seems to me, is the production of petroleum by pressure alone acting
on unaltered shale.

As noted in my discussions of coal, regional carbonization results from
the progressive devolatilization of carbonaceous matter in the strata
on a regional scale under dynamic stresses, dominantly horizontal thrusts,
probably with development of moderate temperatures. It is most
advanced in the regions of apparently greatest thrust compressions
and hence of greatest molecular displacement; and in any region it
is seen to be greatest on the side of greatest cumulative and sustained
horizontal stresses.

With reference to both carbonization and folding, it is important for a
field geologist, prospecting for oil in new regions, to remember that folds
are likely to mark lines of pre-existent weakness resulting from former
anticlinal buckling or faulting in the deeper strata, or that they may occur
in zones of less competence, such, for example, as along zones of marked or
abrupt unconformities; also that buckling and, in particular, overthrusts
are the structural changes (really strains) that compensate and relieve

14 Notes on Principles of Oil Accumulation: Jnl Geol (1919) 27, 252-262.

186 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

the pressure stresses and tend to neutralize them through a relatively
easy and quick shortening of the arc which would otherwise take place
through compression only. The buckling may occur at an early stage
of the thrust, giving comparative relief through the remainder of the
movement and even through the periods of greatest intensity of move-
ment. Accordingly, a buttress of horizontal competent strata under
adequate loading may endure, and undoubtedly has in many cases,
more vigorous and long continued differential stresses, and has sustained
greater molecular displacement and compacting of the rock, incident to
actual compression, than a folded series, even though the thrust may
actually have been stronger and covered a greater distance in the latter
region. The study of the carbonization in a number of coal fields shows
this to be true.

It appears probable that, in regions where the thrusts have been
sufficient to cause well loaded strata to form anticlines, the stresses have
been great enough to cause the generation of petroleum. If these
deductions are well founded, the earlier and minor stresses are connected
with the production of the heavier oils, anomalous or even inexplicable
as this may seem from the chemical standpoint, while the highest grade
oils are usually found where the carbonization, resulting from more intense
stresses, has approached the limit of oil production.

According to these observations, and contrary to the views of most
geologists and chemists, it would appear that the heavy oils, occurring
in regions of less thrust and alteration, are the first products of oil genera-
tion, while the light oils, occurring in the regions of greater thrust, are
the more refined products. Whether the latter are to be regarded as the
direct result of the greater compression of organic matter or, perhaps more
likely, as oils that have undergone subsequent migration, probably with
fractionation by geologic processes, remains to be proved. In this
connection, it is to be borne in mind that the solid residues of heavy
hydrocarbons, devolatilized in the shales and other strata during the
destructive stages beyond the oil limits, are now in evidence as particles
of carbon, causing the blackness of slates, some of which were once
richly carbonaceous shales, and undoubtedly productive deposits of oil
mother substance.

On the other hand, it would appear probable that, in general, oil
either is not present or is not segregated in series of sedimentary forma-
tions that have never been thrust sufficiently to cause some buckling or
undulation under favorable conditions, with the requisite amount of
loading. If not sufficiently loaded, they are likely to remain unconsoli-
dated though they may have been folded. In the Coastal Plain forma-
tions of the Atlantic States, which appear to be but slightly warped and
possibly lack good anticlines and domes, as though the region had been
lifted bodily, without local disturbance, on the back of the metamorphic

DAVID WHITE 187

basement complex, the apparent absence of oil pools is attributed by some
geologists to the lack of folds; this explanation is more likely to be correct
than the view that it is due to the absence of sufficient organic matter
in the formations. But it is also probable that, over much of the area,
the unaltered sedimentary strata have not been thick enough to assure
the requisite loading had moderate folding taken place.

In the genesis of an oil pool not only is the organic debris altered and
devolatilized, with the generation of petroleum and natural gases, as the
result of dynamic thrust stresses attending diastrophic movements, but
the migration and segregation of these hydrocarbons, disseminated in
their place of origin in the mother rock, are promoted, if not caused, by
the molecular rearrangement and the movement of rock grains consequent
to these stresses. Most, by far, of the oil and gas is generated under the
influence of differential stresses in " impervious" beds, the larger part
being formed in the midst of typically impervious deposits, mainly organic
muds, carbonaceous clays, fine-grained shales, and dense organic strata,
such as oil shales, than which few unaltered sediments can be more im-
pervious. The molecular displacement and the readjustments of the
particles of the rock are essential to the migration of the newly formed oil
and gas, and of the water, in the directions of least resistance, which,
other things being equal, will be toward those beds, or regions of beds, most
resistant to pressure and within the pore spaces of which the pressure will
be relatively less. Sandy strata, sandstones with grains varying in size
and shape, porous limestones ; lavas, and, finally, coarse sandstones com-
posed of round grains of uniform size, display varying resistances to
compression, with corresponding variation of pore-space pressure. Coa-
lescence of the infinitesimal globules of oil will take place enroute from the
yielding to the resistant strata; and as the porous resistant beds with
stable grains are traversed, concentration and segregation of the oil, gas,
and water will ensue, the water driving the oil and gas into the larger
voids by reason of its greater capillary tension, whereby it tends to seize
and hold the smaller ones.

The extent to which argillaceous and organic sediments are reduced in
volume under pressure is better realized when one recalls that the sub-
surface layer of a peat bog contains from 80 to 90 per cent, of water, and
sub-surface slimes and muds carry nearly as much. At the lignitic
(brown coal) stage, the average water contents of the coal bed approaches
38 per cent.; the proportions of water in sub-bituminous, low-rank
bituminous, high-rank bituminous, and semi-bituminous coals average
23, 15, 6, and 3 per cent, respectively. 13 To the water losses, a part
of which may be attributed to mere loading soon after deposition,
are to be added the progressive losses of organic volatile matter, including

" G. H. Ashley: Trans. (1920) 63, 782.

188 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

petroleum. The necessity for readjustments of the rock material, as the
process goes forward under heavy loading and powerful lateral thrusts, is
obvious. 14 Rearrangement of the grains in an impure sandstone, or in one
composed of grains varying in size and irregular in shape, will permit less
compression than purer coarse sandstone; while a coarse, porous sandstone
composed of round grains, if not too rigidly cemented, may even change
its shape under lateral thrust without change of volume, until the stresses
become so great as to deform the grains, at which stage carbonization
will have passed the oil limit. All these conditions tend to drive the oil
into the sand having the largest, roundest, and most uniform sized grains.

It may not be out of place here to note that diastrophic movement is
not simple or cataclysmic. It is always in progress in one region or
another, though its magnitude and vigor are specially noticeable in periods
of most marked isostatic adjustment. These periods, though for the
most part relatively short, geologically speaking, doubtless span thou-
sands or perhaps hundreds of thousands of years. The complex movement
of a lateral thrust may be considered as the product of a cycle, or perhaps
a series of cycles of complex differential stresses, possibly cumulative for a
period, then decreasing in force, probably to be renewed again and again
in greater power, until compression, buckling, or displacement have so
far relieved the stresses that they are no longer able to overcome the
rigidity and friction of the strata. There is an obvious contrast between
those strata which relieve the intensity and continuity of a thrust by
buckling, folding, or faulting, and those more competent strata which,
though enduring even more intense stresses, are able to relieve them only
by horizontal compression.

Plainly, then, during these periods of horizontal diastrophic stresses,
the opportunities for progressive readjustment of the particles may have
been almost without number. It is reasonable to conclude also that mo-
lecular rearrangements have attended these stresses, since the chemical
composition of the organic debris and residues has from time to time cer-
tainly been altered, with the generation and expulsion of volatile matter, in-
cluding oil. A study of coajs shows an apparently uninterrupted gradation
from lignite to anthracite and graphite. It would appear, therefore,
that during a period of diastrophic stresses, the conditions have repeat-
edly been favorable for the evolution of the oil, the displacement and
rearrangement of the organic particles and rock grains, the coincident

14 Lateral transfer or flowage, under differential pressures, of the more plastic
argillaceous and organic strata in a series of beds varying in composition and thick-
ness is most natural, and is illustrated by the "horses," " squeezes," "ve:ning,"and
"pocketing" of coal and clays, so familiar to the miner in the bituminous, semi-
bituminous and anthracite fields. Such local flowage may cause thin included sand-
stones or even environing shales to bend in accommodation, thus producing small
local anticlines, some of which may be misinterpreted as depositional.

DAVID WHITE 189

rupture, enlargement, decrease or rearrangement of the pore spaces and
capillaries, the development of zones of varying pressure, the overcoming
of friction, and the disorganization of capillary resistance. In short, the
conditions must have been most favorable (a) for squeezing oil, gas,
and water out of their impervious source, through the intervening, im-
permeable, organic and argillaceous deposits, into the less compressed
regions of the sandy rocks, sandstones, and porous limestones; (6) for
their migration in spite of capillary resistance; and (c) for their eventual
escape into the most porous, coarse-grained reservoir available, where,
under a relative stability of the rock material, segregation and gravita-
tion may be assumed to have taken place, subject to the effect of capil-
lary tension. In some respects, the effects of diastrophic stresses in
compressible sedimentary strata may be likened to a jigging of rock
particles and mineral grains, in which process existing capillaries may
become unstable and disrupted, pore spaces reorganized as to number,
form and size, and friction repeatedly overcome; thus the escape, migra-
tion, concentration, and segregation of water, oil and gas, into less
compressible sandstone and limestone reservoirs were promoted.
Consistent with this interpretation, it would appear that:

1. Oil will be generated only at depths sufficient to assure the neces-
sary loading, which may vary somewhat with the composition and
rigidity of the strata and, to some extent, with the intensity of the
thrust.

2. In oil fields where the stress has been slight and probably confined
to a single period, carbonization (alteration) being in the early stage, the
oil is not likely to be found far, stratigraphically, from the carbonaceous
sediments. If the thrusts have not been sufficient to drive the water, oil,
and gas to a suitable storage "sand," the disseminated oil may not be
recoverable. Water, with its stronger capillary tension, will tend to
drive the oil into the largest pores available. Accordingly, a lenticular
body of open-pored coarse sand may be filled with oil under heavy pres-
sure, independently of anticlinal structure, or even in a shallow struc-
tural depression.

3. The largest oil pools normally occur where ample suitable storage
is convenient to abundant organic mud or mother substance, unless the
thrusts have been too great and carbonization has gone too far. Insuffi-
cient storage in very thin or fine-grained sands may be found in extensive
carbonaceous formations; for example, the thin sands of the Graneros
in the Thornton field, Wyoming, and the fine-grained sands in the Mancos
shale in northwestern Colorado and in the Chattanooga shale in Barren
County, Ky.

4. The stresses of a diastrophic movement may be sufficient to gene-
rate only a part of the oil and gas derivable from the organic mother sub-
stance, leaving some to be evolved under later stresses, until oil is no

190 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

longer produced, though gases may continue to be eliminated until the
organic substance is wholly devolafcilized, leaving only the "fixed car-
bon." 15 From field observations on the progress of devolatilization of
organic matter, it is concluded, as already noted, that the first oils are
generally heavy, usually with considerable asphalt; the later products,
generated in areas of more advanced alteration, are lighter; while the oils
from formations and regions where the carbonization limit has been
approached are characteristically of the highest grade. This is the
reverse of the order in which fractions are obtained by heat distillation.

5. In the course of successive periods of lateral diastrophic stresses,
the water, oil, and gas, under cumulative pressures, may be carried through
relatively impervious rocks for long distances in the direction of least
resistance, if the thrusts and consequent pressures are sufficiently ener-
getic, capillary tension and friction being to some extent counteracted
by the forces which cause rearrangement of the rock particles. For this
reason, several sands may yield oil generated from a single deposit.
Enormous pressures should develop in the lower sands. In fields con-
taining many oil sands, the oil is more likely to be of deep origin.

6. Oil pools generated and localized during one period of stress may be,
and probably have been, carried on to new reservoirs, possibly at differ-
ent horizons, at a later period of greater stress. This may be termed
secondary migration and secondary storage. It seems within the limit
of probability that some of the oil found in sands stratigraphically
remote from recognizably carbonaceous beds may have come from the
latter by secondary if not by primary migration. Given sufficient
stresses in a great thickness of compressible strata, or pressures sufficient
to compress the interlaminated somewhat arenaceous beds, it would seem
possible that some of the water, oil, and gas may be forced comparatively
near the surface before they are trapped in a sandstone beneath im-
pervious cap-rock; finally, if these sandstones lie sufficiently near the
surface to crack, fracture, or buckle under thrust displacement, the oil
and gas may even escape from the strata. Consideration must be given
to the probable depth of erosion that has occurred in a field, where
sands now near the surface are productive.

Whether there is a sort of natural fractionation when the oil pool, at
a later period of stresses, is forced into new and perhaps stratigraphically
higher reservoirs, cannot now be answered definitely. The facts that
(a) the oil disappears eventually in a process of advanced carbonization,
leaving only its solid residues as dark carbonaceous matter in the rocks,

16 This is indicated by the artificial distillation of oil from oil shales in regions
which have undergone varying degrees of carbonization, up to the oil limit; only small
amounts of oil can be obtained from shales which have been carbonized beyond this
limit.

DAVID WHITE 191

and that (6) a thin film of oil, including some of the heavier hydrocarbons,
is left on the grains around which oil has stood, point toward the improve-
ment of the product with each such transfer. This might account for
the progressive refinement of the oils in the course of recurrent periods
of thrusting, as mentioned under paragraph 4. The possible depreciation
of the oil by percolating surface waters, especially those carrying sul-
fates, or by escape of the lighter matter to the surface, must not be
overlooked.

The problems of secondary migration of oil may be as important
as they are interesting, and require further study in both field and
laboratory.

The disappearance of oil pools in areas of too advanced carbonization
may be due to leakage when jointing and cleavage become more highly
developed; or the oil may have been driven to the surface up the dip of
the sands; or, as I am inclined to believe, it may have been volatilized,
the solid residues remaining in the rock.

Whether it is possible for oil and gas to pass through impermeable
clay shales or other cap-rocks except at times of diastrophic readjust-
ment may well be doubted. The extent to which such readjustments
are essential to the migration of oil, gas, and water along a stratum so
composed, as to size of grains and porosity , as to comprise an oil sand,
remains to be experimentally proved; but I am disposed to believe that
their migration through " tight " sands and other so-called impervious
beds takes place under dynamic stresses of diastrophism.

C. E. Van Orstrand suggests that the geologists of the country may
not have given due consideration to the possible influence of osmotic
pressure in moving the oil from deeper and warmer strata, in which it
originates, to the overlying cooler strata or up the dip into the zones of
lower temperature at the apex of an anticline or dome. This subject
has been mentioned by Mr. Van Orstrand in the record of his temperature
observations in several deep wells of West Virginia and southwestern
Pennsylvania. 16 In this connection, attention is called to a brief
discussion, by H. B. Gillette, 17 of the influence of osmotic pressure in
transferring rock solutions from warmer to cooler zones, as relating to
the deposition of orebodies.

The oil in the salt domes of the Gulf Coastal Plain may have originated
in the strata in which the salt plug is found, or it may have ascended
more or less of the distance traversed by the salt. The pressure theory
as to the origin of the salt plugs, which seems to demand acceptance,

16 Discussion of the records of some very deep wells in the Appalachian oil fields
of Pennsylvania and West Virginia, by I. C. White, State Geologist, with temperature
measurements by C. E. Van Orstrand.

Trans. (1903) 34, 710.

192 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

premises local pressures in the surrounding rocks which might be sufficient
to cause the generation of such low-grade oils as are usually found in
these domes. Oil of higher grade would be expected, in general, at
great depth. On the other hand, it has not been proved that the oil did
not ascend with the salt, which seems possible. In the latter case the
domes may deserve testing to a maximum depth. Proof that the oil
was disseminated in the strata, in readiness to migrate horizontally into
the monoclines about a dome when the latter was formed, would support
the theory that the oil was biochemically formed at the time of deposi-
tion of the strata, as suggested by Murray Stuart, 18 separated by
pressure, and segregated gravitationally in the upturned beds
surrounding the plug.

THICKNESS OF SEDIMENTARY FORMATIONS

Whether or not the geologist follows my conclusion as to carboniza-
tion, and its use as an index of incipient regional alteration, the degree of
which approximately determines the limit beyond which productive oil
fields will not be found, he must in any case take into account not only the
alteration of the sedimentary formations, according to his own concep-
tion of the metamorphic limits, but also the thickness of sediments that,
according to his judgment, are not too altered, and hence must furnish
the oil. However, this subject has awakened less discussion, and there-
fore less systematic observation, than its very great importance demands.

It will probably be generally agreed that the requisite thickness of
sedimentary strata in any oil basin depends on the character, composi-
tion, and competence of the strata; the position of the sands and the cap-
rock; the distribution of the mother substance; the structure, the jointing,
faulting, erosion, conditions of deposition, etc. Mother substance, reser-
voir sands, or cap-rock may, of course, be lacking, but for purposes of
discussion, it must be assumed that they are all present and favorable,
i.e., the organic matter is near but not at the bottom, and the reservoir
and cap-rock are next above it. Further, a consideration of the requisite
thickness must take into account the probable depth of strata eroded since
the oil was generated and brought to its present storage. In other words,
the original thickness at the time of deformation by horizontal stresses
is to be regarded, rather than the present thickness in the producing
basins, for the original thickness is what determined the amount of load
on the organic beds when dynamic action occurred.

A review of the field evidence circumstantially presented by oil fields
possessing relatively thin and not too altered strata, lying on a crystal-
line or thoroughly metamorphosed basement complex, would be both

18 Records Geol. Survey India (1910) 40, 320-333.

DAVID WHITE 193

interesting and valuable, but the data seem insufficient for definite con-
clusions. I do not recall any oil field, meeting the conditions above men-
tioned, in which the non-metamorphosed sediments originally aggregated
less, in round numbers, than 2000 ft. (600 m.) ; in most cases the thickness
is over 2500 ft. (760 m.). ' Exceptions should be made of series marginally
overlapping on metamorphics, like the Pennsylvanian and Permian on
the buried igneous and metamorphic rocks in portions of the Mid-Conti-
nent region, where the hydrocarbons may have migrated diagonally
through the littoral sands of the relatively steeply transgressive
formations.

The question of thickness is possibly of great importance in regions
like the Atlantic Coastal Plain, where unaltered and largely unconsoli-
dated sediments lie on pre-Cambrian complexes; also in portions of the
Atlantic Trias. As to the Atlantic Coastal Plain, over the greater por-
tion of which the thickness of the Coastal Plain deposits is almost cer-
tainly less than 2200 ft. (670 m.), while throughout large areas it is less
than 1200 ft. (366 m.), it may be questioned whether, if thrusts sufficient
for the generation and migration of oil into coincidentally induced folds
had been exerted, the sediments were sufficiently thick to provide
enough loading to favor the generation, segregation, and retention of
the oil and gas. Almost surely the thickness has been too little, also,
over considerable areas in those marginal zones of the Coastal Plain
formations in the Gulf embayment, where the Cretaceous and Tertiary
sediments lie on metamorphic or crystalline series.

On the other hand, the presence of oil in relatively thin sediments
overlying other sedimentary formations, in which the carbonization has
not gone far beyond the limit cited above, may not be precluded, in
accordance with the suggested migration of hydrocarbons during recur-
rent periods of thrust stresses. The Madill, Okla., field seems to offer
an illustration. The stresses inducing incipient metamorphism in an
unconformably overlying formation must further alter the lower forma-
tion, which may already have nearly reached the carbonization limit.
However, the presence of oil pools in thin unaltered sediments, where the
alteration of the carbonaceous debris in underlying formations has
progressed considerably past the carbonization limit say, into the
semi-bituminous (fuel ratio 3.0 or more) or the semi-anthracite rank
would be very interesting and worthy of record. In such an occur-
rence, the questions will be: Did the oil (a) originate in the lower series
and pass into the younger by primary or secondary migration, as seems
most probable; (6) condense from vapors generated in the lower series
during the progressive alteration after the upper sediments were laid
down; or (c) originate in the upper series?

The evidence bearing on these questions is not sufficiently complete
and coordinated to encourage a satisfactory discussion at this time, due

VOL. UCV. 13.

194 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

largely to the lack of observation on carbonization and other indices of
incipient metamorphism of the sediments, including the carbonaceous
deposits. Factors to be considered in this connection include uncon-
formities at erosional intervals, as affecting the escape or deterioration
of oils near the old erosion surfaces; migration of oil and gas up the dips
to the margins of transgressing formations or through littoral zones to
higher formations; thicknesses of rock eroded from producing formations;
and the effects of sealing on oil pools in the sands. The application of
the problem to many regions is obvious.

CONDITIONS OF DEPOSITION

Aside from such facts as the presence of adequate organic matter,
of sands suitably composed and situated for service as oil reservoirs, of
cap-rocks properly located, etc., some of which have already been men-
tioned, a question which should not be ignored in the search for oil
in a new region, such, for example, as the Tertiary freshwater basins of
eastern Washington and Oregon, or in the Great Basin region, is whether
or not the beds concerned in the generation and storage of the oil are
strictly of freshwater origin, and particularly whether the oil-bearing
series was laid down in an exclusively non-marine basin. Inseparably
connected with this question is the related one as to the importance of the
association of salt water or gypsum in the oil-producing formations, as is
so insistently urged by some geologists, with citation of circumstantial
evidence. On these matters opinion differs widely, possibly without
succinct data sufficient for a final decision.

As criteria to be considered in the answering of this problem the
following may be noted:

(1) Ample organic matter undoubtedly suitable for the generation
of oil and gas was deposited with the sediments in many of the fresh-
water basins. These deposits contain oil shale of high quality, which,
on distillation, yields oil essentially like and possibly indistinguishable
from that obtained from oil shales of marine origin. Many of the organic
products are common to both habitats.

(2) The mechanical constitution of the deposit in both marine and
freshwater formations is essentially the same.

(3) Important oil-bearing sands and organic remains were deposited
during intervals, sometimes of considerable length, during which only
freshwater sediments were laid down, these deposits being intercalated
in brackish water or marine sediments.

(4) Oil-bearing sands and organic deposits were laid down in waters,
but slightly saline, in the younger formations of the Appalachian trough.

(5) Some salts are present in freshwater deposits.

(6) Natural gas is present in freshwater basins, and has been devel-
oped at considerable depth in such basins.

DISCUSSION 195

(7) While it may be true that, in the geologic processes of oil genera-
tion, salt in amounts premising marine or brackish water deposition may
be essential as a catalyzer or otherwise, the fact remains to be demon-
strated, possibly in the laboratory. The absence of salt does not appear
to affect the artificial production of oil by distillation of shale.

It is possible that in some of our oil fields, salt water may have found
its way downward through joints or along the dip into fresh- water beds
subsequently submerged beneath the sea, somewhat like the invasion
of fresh water down the dips of some of the marine oil sands in California.
On the other hand, fresh- water basins in which the requisite conditions
as to depth, organic matter, sands, cap-rocks, thrusting, and incipient
alteration favorable for oil pools are fulfilled, and which have never sub-
sequently been submerged beneath the sea, have been too little tested
to justify conclusions as to their possibilities for oil production. Such
basins, if actually closed and without outlet, will be more or less dis-
tinctly alkaline. At the present stage of our knowledge, fresh-water
basins appearing otherwise to meet the requirements should be wildcatted
without prejudice.

DISCUSSION

R. H. JOHNSON, Pittsburgh, Pa. It seems to me that the case for
the fresh-water origin of natural gas must be accepted, since the coal
progressively loses methane. We know that much natural gas must
have arisen in that way. My reserve in connection with petroleum in
contrast with natural gas comes from the fact that if the fresh-water
deposits have been as productive of petroleum as the marine, the field
evidence ought to show us more petroleum in close proximity to the coal;
it is this that leaves me skeptical as to very much fresh-water petroleum,
although we must admit a great deal of fresh- water natural gas.

H. W. HIXON, New York, N. Y. In the Appalachian field, how
much oil and gas do you find above the coal? I am not well informed
on that subject, but I have not heard of a case where oil and gas occurred
above the coal in Pennsylvania or West Virginia, except possibly that
which had migrated there along a fault. There is another thing, you
cannot saponify petroleum and you cannot make glycerine out of petro-
leum. If you could do that, why should we have paid such high prices
for glycerine during the war? You can saponify organic oil and you can
make glycerine out of animal fats, so that the petroleum and animal
fats differ entirely. Also, petroleum has no food value.

We differ fundamentally as to our ideas about the origin of petro-
leum and natural gas, and I think we will have to let it go at that. As
regards the origin of the force, the dynamic force, that causes these
deformations, the elevation and folding, I consider that these gentlemen

196 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

are laboring under the impression that it is contraction. I have studied
that question for a number of years and find that the best authorities on
the subject state that the total amount of contraction of the interior of
the earth, due to loss of temperature, in 100,000,000 years would prove
a circumferential contraction of about 7 miles, and that if all of the folding
and faulting and overthrust of the various mountain ranges of the earth
were ironed out, they would amount to something like 150 to 200 miles.
There is a decided difference that has to be accounted for. I account for
it in an entirely different way; that the gases which cause elevation by
reduction of density, as the surface of a loaf of bread is raised by reduction
of density, tend to accumulate and migrate toward the axis of elevation.
They carry the crust in two directions and, because of the reduced den-
sity, creep toward the axis of elevation or toward the center of the
dome. The hydrocarbons are in the gaseous interior of the earth for
exactly the same reasons as all the other gases because of the diffusion
of gases in the original gaseous planet in that gaseous core, and they have
remained there ever since, being held by the power of diffusion. The
change from the gaseous to the solid condition is by loss of temperature.
It then becomes lighter at the same time, because the gaseous core must
be denser than the solids that lie upon it.

My contention is that petroleum, natural gas, and the helium with
them are of volcanic origin. The origin of oil and gas is connected with the
whole theory of earth physics, which is entirely different from the old
contraction hypothesis, on which most of the geologists base their theory
of mountain formation.

The authorities on the subject state that the earth's crust, considered
as a dome, is not capable of supporting one five-hundredth part of its
own weight. If it is not capable of supporting any more than that por-
tion of its own weight, it must be supported by the material below it at
all time?, whether it is above sea level or below sea level. We find rocks
of marine origin in the highest mountains. They did not get there by
accident; and if they were supported by the material below them at all
times, and they are above sea level at one time and below sea level at a
previous time, the only possible solution of that problem is that the
matter below the zone of fracture has varied in density between those
two periods. So that you come to a question of accounting for that
variation in density between two geological periods; that, I maintain,
is due to the accumulation of magmatic gases derived from the gaseous
core denser than the solids which will form out of it when cold.

DAVID REGER,* Morgantown, W. Va. Regarding the statement just
made that oil has not been found above the coals in the Appalachian
Basin, I would like to say that one of the first wells in the West Virginia

* Assistant Geologist, West Virginia Geol. Survey.

DISCUSSION 197

fields was about 300 ft. deep, at Burning Springs on the Little Kanawha
River in 1860. When I visited the well in 1909, 49 years after its com-
pletion, it was still producing 30 bbl. of oil a month and 10 years later,
in 1919, was still producing. Only the owner knows how many thousands
of barrels the well has actually produced in that time. The producing
formation there was the Cow Run sand, which is right in the middle of
the Coal Measures. This well is on the Burning Springs which extends
half way across the state. The great producing sands have been the
two Cow Runs, which have coal measures above and below them. It
is my opinion that while the first oil in the state was found in the coal
measures, it is entirely possible that the last drilling and the last produc-
tion of oil to be eventually found in the state will be in the same coal
measures.

H. W. HEXON. I believe I stated that if the oil or gas migrated to
that particular place along a fault it might be found there, but it all comes
from below the coal.

DAVID REGEB. There is no fault there.

J. F. DUCE, Denver, Colo, (written discussion). The question
of the presence of carbonaceous material in the "Red Beds," is an old
one. The Triassic " Red Beds " of New Mexico are certainly carbonaceous
and at times bituminous. Certain of the sandstones are crowded with
fossil wood, while directly above these wi^ be found bituminous sands.
This is true also in the Dockum of Texas. Of the underlying strata
in northern New Mexico we cannot be so certain, as they are largely
arkoses. The basal members of the Manzano group contain some lime-
stones, but M. G. Girty states that the fossils are not well preserved,
which suggests erosion on the sea floor before entombment.

In the southern part of New Mexico, the occurrence of the limestones
and bituminous shales of the Guadalupe Group at the base of the Triassic
and the great thickness of limestones in the Manzano (Hueco) suggests
the presence of petroleum; these same rocks are probably the source
of the oil in the artesian wells of the Roswell area.

It is perhaps well to bear in mind that the criterion that White sug-
gests concerning the state of metamorphism of the coals in an area is
applicable but locally in the Rocky Mountains. We are confronted
there with exceedingly rapid structural changes, and it is along the axes
of these changes that the coal fields White has mentioned occur. Recent
investigations by Richardson, Lee, and Ziegler have changed our con-
ception of Rocky Mountain structure. The steep monoclines that form
the mountain front die out abruptly both east and west, and seem in
some cases to have been accompanied by strike faults. The zone of
intense folding is therefore narrow and is frequently associated with

198 GENETIC PROBLEMS AFFECTING SEARCH FOR NEW OIL REGIONS

volcanic activity. Along the flanks of these sharp folds most of the pro-
ducing Rocky Mountain coal fields are grouped; here, too, there is the
maximum metamorphic effect, so that the coals are of high grade. As
we pass from the folding, the coal becomes poorer and poorer. The
coals in the Trinidad field are associated with the intrusives of the
Spanish Peaks group, the coals of the Durango field with the intrusives
of the San Juan group, the coals of Crested Butte with the Crested
Butte intrusives, and those of the Anthracite Range with the Elkhead
Mountain intrusives. This connection is surely not accidental. In
one case, however, at New Castle, the high-grade coals are not associated
with eruptives but with sharp folding alone. (Basalt flows are present
in the near vicinity but I am speaking here of intrusives). If now we
pass from the focus of folding and igneous activity but a short distance,
the grade of the coal changes markedly, and in accordance with White's
theory. We musJb, therefore, restrict this criterion of the fuel ratio of
the associated coals to the locality in which the coals occur and cannot
extend it generally to formations beyond the field in which the high
fuel ratio coals occur. Further than this, if petroleum migrates up
the flank of Rocky Mountain monocline, we would expect even within
the metamorphic areas petroleum that had migrated from farther down
the slope where unmetamorphosed sediments occur, unless the metamor-
phism has reached a point where the porosity of the strata through which
it must migrate has been affected. Lighter oils would, however, be
expected, as the long journey would result in the fractionation of the
original oil.

In connection with the origin of petroleum, it is interesting to note
that almost all the Cretaceous oil of Wyoming is produced from the
lower Colorado group, and that the oil sands are directly associated with
the bituminous shales of the Mowry and equivalent formations.

PETROLIFEROUS PROVINCES 199

Petroliferous Provinces *

BY E. G. WOODRUFF, f TULSA, OKLA.
(Chicago Meeting, September, 1919)

THE earlier struggles in petroleum geology were directed to solving
the origin and method of accumulation of petroleum. We are now
fairly well agreed on those subjects. Most of us think that the great
mass of petroleum commercially produced comes from plants or animals,
or possibly from both. We are confident that the oil was not produced
where it is now found but has accumulated in reservoirs of various kinds.
The types of reservoirs are certainly variable but they just as certainly
follow definite geologic laws. Some of these types of reservoirs can be
determined from surface study; others cannot. We know, too, that these
types of reservoirs (largely structures such as anticlines, domes, and
terraces) are much more widespread than the oil pools. In other words,
there are many places where good sands and good structures exist but
where oil is not found. It is the purpose of this paper, therefore, to
attempt to analyze, from a regional standpoint, some of the conditions
that control the presence or absence of oil pools and to group them in a
regional way, hence the term "Petroliferous Provinces." The paper
lays no claim to presenting new facts but attempts to group and classify
the information that so many have expressed again and again.

The essential factors for an oil field are petroleum, a reservoir material,
and conditions under which the petroleum can enter the reservoir but
cannot escape except through the drill holes. The paper will first dis-
cuss the source of petroleum as it occurs in definite regions, then the
regional arrangement of reservoir strata, and finally the areal arrange-
ment of structures.

To have petroleum, there must be a source. Since living matter
is considered the source of the petroleum, geological conditions must
have been such that living organisms were abundant. Arid regions
on the earth's surface have not given rise to living things in sufficient
abundance to produce oil; similarly, too cold regions and saline inland
lakes. The converse of this is that warm moist conditions must prevail
to produce an abundance of vegetable matter. Before an area can be

* Paper prepared for meeting of Tulsa Section, Feb. 25 and 26, 1919.
t Chief Geologist, Oklahoma Producing and Refining Co.

200 PETROLIFEROUS PROVINCES

considered a petroliferous province, it must have had an abundance of
living things from which the oil could have been derived. On this basis,
certain classes of petroliferous provinces may be distinguished.

Igneous Rocks. It is evident at once that petroleum cannot come
from provinces in which there are nothing but igneous rocks. One does
not expect petroleum in the granite regions of the Rocky Mountains
or the Hudson Bay, large areas in western Georgia, North and South
Carolina, central Maryland, southeastern Pennsylvania, and north-
eastern New York. If life was ever abundant in these provinces, the
remains have been eroded away. They are certainly non-petroliferous
areas.

Metamorphic Rocks. Organisms may have been abundant in the
rocks from which the metamorphics came but the geologic processes are
such that the petroleum must have been driven from the rocks if there
was ever any in them. Geologists exclude these areas of metamorphic
rock from the petroliferous provinces, because there can be no source
for the oil in them.

Sedimentary Strata. Almost any sedimentary rock may be a source
of petroleum but to the commercial geologist some are impossible
of petroleum production, whereas others are improbable and others
probable.

Lower Paleozoic Strata. The very old sedimentaries, pre-Cambrian,
Cambrian, and Ordovician, have not been productive of petroleum to
any considerable extent. It is probably because, during those ages of
the earth, life was not sufficiently abundant to accumulate in quantities
large enough to produce petroleum in commercial quantities. Possi-
bly, too, the geological forces have been operative so long and locally
so intensively that the petroleum has been driven from the strata if any
ever existed in them. On this basis, we look with doubt on a large part
of Arkansas, part of Missouri, certain areas in Ohio, Tennessee, Kentucky,
most of Minnesota and Wisconsin, northern Illinois, the belt of closely
folded strata from northeastern Alabama to New York, and practically
all of New England. By this process of elimination, possible petroliferous
provinces are greatly restricted.

Middle Paleozoic. The Middle Paleozoic strata have been produc-
tive but have produced only locally. It is probable that, by that geolog-
ical time, the animal life had become sufficiently abundant locally but
only in the most favorable localities to be a source for the oil; therefore,
if the province under consideration has only Silurian or Devonian strata it
should be considered and probably classed from the standpoint of the
life condition that prevailed during the period of deposition. If the
paleogeographic conditions were such that life was abundant, the prov-
ince may be petroliferous; but if life could not abound, then the prov-
ince must be non-petroliferous.

B. G. WOODRUFF 201

Carboniferous and Younger Strata. The upper Paleozoic and all
younger strata must be classed as possibly petroliferous. But in classify-
ing provinces embracing these strata, a criterion that should be applied
is the presence or absence of such paleogeographic conditions as supported
life in abundance or suppressed it. Largely on this basis the writer has
tentatively classed areas in Iowa, Nebraska, Kansas, and Arkansas as
non-petroliferous. He is fully aware that the facts are as yet meager and
incompletely studied and that petroleum may be produced in some of
them, but certainly they must be considered doubtful. Areas classed
as promising on this basis are in Pennsylvania, West Virginia, Kentucky,
Tennessee, Alabama, Ohio, Indiana, Illinois, Kansas, Oklahoma, and
Texas. Even some of these must be classed as non-petroliferous on the
basis considered later in this paper.

Our second broad division in classifying any province as petroliferous
or non-petroliferous is the character of the reservoir stratum. As
we know, the most reliable stratum is a sandstone, its continuity of
porosity and the resistance to closing of pores under compression render
it the most reliable; next to the sandstone is porous limestone or dolomite;
and, finally, shale. Other classes of reservoirs are practically negligible
because the amount of oil reservoired in them is very small.

The ability of a sandstone to reservoir petroleum depends on its
freedom Irom material that will fill the pore spaces. This may be diffi-
cult to prophesy in advance of actual drilling, but we can achieve a
considerable degree of success by studying the conditions under which the
material was deposited. Sandstone composed of quartz derived from
the granites must be open, if deposited in fresh, or comparatively fresh,
water not far from the source. On the other hand, if the sand has been
transported a long distance from the source or deposited in land-locked or
very saline basins, its pore spaces are filled and it cannot become a reser-
voir stratum. As a concrete example, the sandstones now forming along
the rivers debouching from the front range of the Rocky Mountains are
almost universally porous but none of us will expect the sandstones form-
ing in Great Salt Lake to be porous. My associates who studied the
petroleum conditions of Cuba found the sand there to be derived largely
of fragments of gabbro from the great gabbro masses nearby. Appar-
ently, these fragments were fresh when deposited as sand but after deposi-
tion they disintegrated sufficiently to allow enough clay to fill the pore
spaces and compact the whole mass, thus closing the porosity of the
sand and preventing it from becoming a reservoir stratum. Some sand
reservoirs are derived by the disintegration of previously deposited
sandstones, such as the Tertiary sands along the Texas Gulf Coast. They
follow the same laws as the sands deposited primarily from the granites.

Thus, the basis on which to classify sand reservoirs must rest on
paleogeography or on the character of the sand and the relation of the

202 PETROLIFEROUS PROVINCES

present position of the sand to the source. Let us look at it in another
way. Take the map of the oil fields of the United States, with the
possible exception of the Gulf Coast; in the fields in which sandstones
are productive, the sandstone beds were laid down just off the flanks of

LEGEND.

Pel-roll farous Provinces.

Areas in which onlu non-pS
roliferous sedimnv s occur.
Ar s in which sedimentar
atrucrural condition*
are unfavorable.

FIG. 1. MAP OP NORTH AMERICA SHOWING PETROLIFEROUS PROVINCES.

paleozoic mountains. The converse of this is that sands far from their
source are not productive because the pore space is closed by clay or salts.
The writer feels that even the Gulf Coast fields are an apparent exception
only because those sands are secondary and derived from the breaking up

E. G. WOODRUFF 203

of strata not far away. On the basis of sand study, the petroliferous
provinces outlined on the accompanying map are presented.

With our present very limited knowledge of the condition of limestones
underground, no reliable classification of provinces can be made. Some
geologists have presented data to show that the limestones are cavernous
or porous, whereas others have shown that they are creviced only. At
present we must consider all limestone possibly capable of reservoiring
petroleum until proved otherwise, but the writer clings to the idea that
the time will come when certain provinces will be delimited in which
the limestones will be known to be non-petroliferous because the lime-
stones are non-porous or non-creviced.

The writer is beginning to feel that possibly one distinction may be
made, based on the purity of the limestone, which, of course, again de-
pends on the paleogeographic conditions that prevailed when it was
deposited. The limited number of petroliferous limestone cuttings
that have come under the writer's observation are very siliceous (generally
cherty). The writer is inclined to believe, though he is not ready to
apply it as a criterion, that only cherty limestone beds produce petroleum
in commercial quantities. The crevices in shale offer a very limited
reservoir space, so limited in fact that shale beds as such must always be
considered as having doubtful commercial petroleum value.

If the third, but probably the most important, set of criteria to be
applied in delimiting petroliferous provinces is structure, the types of
structure necessary for the accumulation of petroleum have been so
thoroughly discussed that a repetition is unnecessary. These structures
are the results of tectonic forces and are, therefore, grouped according to
certain laws. Again we are without sufficient data on which to base a
grouping of these structures. Certainly structures are most numerous
on the periphery of the great structural basins. They are not too close
to the mountains surrounding the basins but certainly not far away.
They seem to bear a certain zonal arrangement.

To apply these criteria a set of maps may be constructed: first, to
show the petroliferous provinces on the basis of geologic age; then to
restrict the petroliferous provinces thus outlined by striking from them
the overlapping parts of the non-petroliferous provinces on the basis of
reservoir material; and, finally, to restrict on the basis of structural
groupings. On these bases the writer presents the accompanying map
of North America. He recognizes that it is imperfect but hopes that it
may form a basis on which an accurate map may be constructed.

This map shows petroliferous provinces as follows:

1. In Western Alaska. Oil seeps are known in this province; there
has been some drilling but as yet no considerable production.

2. In Western Canada from the Arctic Ocean to and including

204 PETROLIFEROUS PROVINCES

Canada. Some commercial production may be found in the northern
part of this province; the southern part is of doubtful value.

3. Along the Pacific Coast in California, Oregon, and Washington.
Only the southern part of this province seems important.

4. In Wyoming, Colorado, and a part of New Mexico. Only small
areas in this province will be productive.

5. In Oklahoma, Texas, and Louisiana. Considerable areas in this
province are productive and others probably will be found.

6. From Pennsylvania to and including Illinois and extending south-
ward into northern Alabama and Mississippi.

7. In Lower California. This province seems of doubtful value but
may be productive.

8. On the eastern coast of Mexico.

These are the broader subdivisions of North America. On the same
basis and by the same methods each province may be subdivided in
areas in which petroleum may be found and thus a set of maps built up
that will limit the areas in which the geologist and prospector may hope
for success. Then, as our knowledge is perfected, the principles may be
applied to South America, Europe, Asia, Africa, and Australia, thus
greatly aiding pioneer work in those countries and rendering the fuller
application of geology immensely valuable in the ultimate development
of the world's petroleum resources.

DISCUSSION

CHARLES SCHUCHERT,* New Haven, Conn, (written discussion).
I embrace the opportunity to take part in a discussion of Mr. Woodruff's
paper because a successful discerning of what actually constitutes petro-
liferous areas from the geologists' standpoint is worthy of our endeavors,
not only from the intellectual side, but also because it may lead, as Mr.
Woodruff hopes, to the more certain establishment of principles that
can be applied to other continents in exploiting them for petroleum.
This discussion will also embrace the results of two other recent papers,
one by Alexander W. McCoy and one by Maurice G. Mehl. 1

Sources of Petroleum. Mr. Woodruff is agreed that petroleum comes
from plants and animals, or possibly from both, and that it has ac-
cumulated by migration into reservoir rocks. These reservoir rocks
must of course be porous to become catch basins for the oil and gas,
and then, too, their present structures are variable, as they occur in
anticlines, domes, terraces, etc. The structures, he states, are more

* Curator, Geological Dept., Peabody Museum of Natural History.

1 A. W. McCoy: Notes on Principles of Oil Accumulation. Jnl Geol (1919) 27,
252-262.

M. G. Mehl: Some Factors in the Geographic Distribution of Petroleum. Bull.
Sci. Lab., Denison Univ. (1919) 19, 55-63.

DISCUSSION 205

widespread than are the oil pools, and the same is true for the reservoir
rocks. Accordingly, there must be many good sands and structures
that have no petroleum. On the other hand, there are conditions in the
making of the hydrocarbons that are not formulated by Woodruff or
are not clearly in mind. These are: Petroleum is not formed in sufficient
quantities to be commercially available in the fresh-water or subaerial
deposits of the lands, the continental deposits. For practical purposes
all such should therefore be excluded, at least for the time being
from further consideration. Moreover, land climates have but little
direct bearing on the temperature necessary for life in the seas where
the petroleums are formed, because there is an abundance of life in all
shallow, marine waters of whatever clime. Again, there has been abun-
dant life in the seas of all times, not only since the Cambrian, but ever
since the Archeozoic. The proof of this is seen in the high state of
organic evolution attested by the earliest Paleozoic fossils, and in the
nature of the marine formations of the Proterozoic and Archeozoic strata,
with their high carbon content. All of these differences between us will
be discussed later.

Areas With and Without Petroleum. Mr. Woodruff is seeking for the
regional conditions that originally controlled the formation of the hydro-
carbons and their later storage into oil reservoirs. In this way he is led
to point out the petroliferous provinces. The conditions that make for
oil provinces he holds to be three:

1. The source of petroleum lies in the end-results brought about
through the decay of organisms, and the preservation of the residues
is limited to certain environmental conditions. There are great areas
that have always been devoid of the required life conditions, and others
where the entombed organic residues have been dissipated by the defor-
mational processes.

2. Petroliferous areas are limited by more or less definite characters
in the oil-preserving and oil-storing strata.

3. Petroliferous strata have more or less definite deformational
structures.

The ideas which, in our opinion, lead to the ascertaining of the pet-
roliferous and non-petroliferous rocks of North America are :

1. The impossible areas for petroliferous rocks.

(a) The more extensive areas of igneous rocks and especially

those of the ancient shields; exception, the smaller dikes.
(6) All pre-Cambrian strata.

(d) All regionally metamorphosed strata.

(e) Practically all continental or fresh-water deposits; relic seas,
so long as they are partly salty, and saline lakes are excluded
from this classification.

206 PETROLIFEROUS PROVINCES

(/) Practically all marine formations that are thick and uniform
in rock character and that are devoid of interbedded dark
shales, thin-bedded dark impure limestones, dark marls, or
thin-bedded limy and fossiliferous sandstones.

(gr) Practically all oceanic abyssal deposits; these, however, are
but rarely present on the continents.

2. Possible petroliferous areas.

(a) Highly folded marine and brackish water strata younger than
the Jurassic, but more especially those of Cenozoic time.

(6) Cambrian and Ordovician unfolded strata.

(c) Lake deposits formed under arid climates that cause the
waters to become saline; it appears that only in salty waters
(not over 4 per cent.?) are the bituminous materials made
and preserved in the form of kerogen, the source of petroleum ;
some of the Green River (Eocene) continental deposits (the
oil shales of Utah and Colorado) may be of saline lakes.

3. Petroliferous areas.

(a) All marine and brackish water strata younger than the Ordo-
vician and but slightly warped, faulted, or folded; here are
included also the marine and brackish deposits of relic seas
like the Caspian, formed during the later Cenozoic. The
more certain oil-bearing strata are the porous thin-bedded
sandstones, limestones, and dolomites that are interbedded
with black, brown, blue, or green shales. Coal-bearing strata
of fresh-water origin are excluded. Series of strata with dis-
conformities may also be petroliferous, because beneath
former erosional surfaces the top strata have induced porosity
and therefore are possible reservoir rocks.

(6) All marine strata that are, roughly, within 100 miles of former
lands; here are more apt to occur the alternating series of thin-
and thick-bedded sandstones and limestones interbedded with
shale zones.

Experience has shown that commercial quantities of petroleum do
not occur in areas of igneous rocks, nor in regions of highly folded, mashed,
and decidedly metamorphosed strata that as a rule are older than the
Tertiary. Nevertheless, it will not do to say, because strata are decidedly
folded and faulted, that in the areas of mountains there can be no commer-
cial quantities of oil, for we know that the petroleum fields of the Coast
ranges of California and those of the trans-Caspian countries have yielded
vast quantities. Here, however, the oil-yielding strata are essentially
of Cenozoic age. It appears that the main regions for oil production in
North America will be the more or less flat-lying sedimentary formations
the vast geologically neutral area to the east of the Rockies and to
the west of the Appalachians. Also, in a broad and general way, the

DISCUSSION 207

older the geologic formations, the more devoid they are apt to be of pe-
troleum; and the more often a given area has been subjected either to
mountain folding or to broadly warping movements, the more certain
it is that all or most of the volatile hydrocarbons have been dissipated.
Such places are apt to have the hydrocarbons only in fixed form and not
as kerogen. In strata older than the Cretaceous, the deformed geologic
structures of varying sorts should be rather of minor than of major
strength as an essential to oil accumulation in commercial quantities.

Original Oil Strata. It appears that zones of petroleum, in general,
do not occur in thick deposits that are continuously of the same kind of
material, as sandstones, limestones, or shales, but in or near sandstones
and thin-bedded porous limestones that are interbedded with bituminous
shales. McCoy says that in the mid-continent field the petroliferous
shales "are generally dark colored, often black, and carry bands of highly
bituminous material." Such bands "are often described by the drillers
as coal, asphalt, or black lime, according to the hardness and appearance
of the material. The shales are typical oil shales, quite similar in char-
acter to those (of the Cenozoic) of Colorado and Utah."

Petroleum of Organic Origin. The hydrocarbons are the chemical
end-results of organisms and, in the main, are the fatty substances de-
rived through bacterial decomposition from the plants and animals once
living in the sea waters. This is a conclusion not always clearly in the
minds of petroleum geologists.

One is led, Dalton 2 states, "to regard the great majority of oils as
derived from the decomposition during long ages at comparatively low
temperatures of the fatty matters of plants and animals, the nitrogenous
portions of both being eliminated by bacterial action soon after the death
of the organism. The fats and oils from terrestrial fauna and flora may
have taken part in petroleum formation, but the principal role must, from
the nature of most petroliferous deposits, have been played by marine
life."

The decomposition bacteria attack the cellulose of the plants and the
nitrogenous tissues of animals, leaving untouched the fatty materials.
The reason why the fats remain untouched is probably because the feeding
of the bacteria is stopped by sedimentation, which buries and kills the
decomposing organisms living beneath the surface of the sea bottom.
Dalton further states that "Peckham's view, that asphaltic oils are
mainly of animal origin, while paraffin is largely derived from vegetables,
is worthy of acceptance on general chemical as well as geological grounds,
since Kramer and Spilker, and others, have shown that vegetable fats
produce paraffin either with or without artificial distillation, and the
limestone oils, which on geological grounds are generally held to be mainly

2 Leonard V. Dalton: On the Origin of Petroleum. Econ. Geol (1909) 4, 603-631.

208 PETROLIFEROUS PROVINCES

of animal origin, are notably asphaltic." In general, the Palaeozoic
petroleums have paraffin bases, and it seems probable that all those de-
rived from black petroliferous shales are largely, if not wholly, of marine
algal origin. Usually we do not realize the extraordinary importance
and abundance of plant life, but when we think that all animals are in the
ultimate dependent for their existence upon plants, we begin to perceive
the truth of the following forceful statement by the English botanist,
F. F. Blackman, 3 who recently said that "Botany, as the science of plants,
claims dominion over some 99 per cent, of the living matter on the
surface of the earth and over most of the fossil remains under the
surface."

Petroleum Essentially of Marine Origin. It is, however, plain to all
who have looked into the matter that petroleums cannot accumulate
upon the dry land in deserts, grassy plains, or forests, for here the oxidiz-
ing influences are so active that all the volatile parts must be taken away
or completely changed. In lakes, organic decay is, as a rule, so rapid
that limy marls are deposited, and it seems to be exceptional that black
petroliferous muds are of fresh-water origin. The extensive oil-shale
deposits of the Green River series of Utah and Colorado are certainly
not of marine origin, as they are devoid of marine organisms and are
underlain and overlain by river flood-plain deposits of early Eocene age,
as is shown by their contained land animals and plants. The hydro-
carbons appear to be of drifted plant origin, according to Charles A.
Davis, and as kerogen does not form in large quantities, the evidence
appears to indicate that the water in which the Green River shales were
deposited was slightly saline. Therefore the chemical end-result of or-
ganic decay, the kerogen, cannot accumulate in commercial quantities
except beneath a sheet of salt water, and these sheets of water probably
are in the main within the limits of a few hundred feet of depth; the
deeper the water basins, the more certain the amount of oil accumulation,
under these given conditions. Salt water and organisms are the first
requisites for kerogen making in nature and, accordingly, the hydrocar-
bons are stored almost always in marine sediments; these are chiefly
the black and brown shales and the impure dark thin-bedded limestones.
All rock formations accumulated directly beneath the atmosphere, as
the pure continental deposits, must therefore be devoid of commercial
quantities of petroleum. Then, too, all deposits, either of the fresh
waters or of the seas, which are periodically subjected to atmospheric
weathering during their time of accumulation, are also lacking in oil in
paying quantities. Hence we may further conclude that all red or reddish,
yellowish or white, rain-pitted or sun-cracked deposit, either of conti-

*New Phytologist (1919) 18, 58.

DISCUSSION 209

nental, fresh-water, or semi-marine origin, are lacking in petroleum in
large amounts.

McCoy informs me that an average oil shale yields, at temperatures
between 500 and 1200 F. (260 and 648 C.) about 20 gal. (75 1.) of oil,
and from 15 to 18 Ib. (6.8 to 8.1 kg.) of ammonium sulfate per ton of shale.
In the spent shale there still remains from 15 to 20 per cent, of fixed
carbon, but no ammonium sulfate. The bituminous material in unspent
shales, he states, "occurs in solid form, as none of the ordinary solvents
show coloration after solution tests. Upon distillation, such shales have
given off petroleum." This "solid organic gum called kerogen" can be
changed in the laboratory to liquid hydrocarbons by heat. In nature,
this may be brought about possibly by intense friction developing heat,
but more probably only in deep-seated water-bearing strata accordingly,
in formations that are under greater pressure. However, " pressure alone
can cause no change in this material when the included water is not
allowed to escape." On the other hand, "the maximum static pressure
available in any porous zone is a function of the size of the openings
around that stratum. The determining factor is the capillary resistance
of the water in the adjoining small openings." In other words, the solid
kerogen "is only changed to petroleum in local areas of differential move-
ment. . . . After such a change is made, the accumulation of oil into
commercial pools is accomplished by capillary water; and the interchange
only takes place in local areas where the oil-soaked shale is in direct
contact with the water of the reservoir rock. Such conditions are
explainable either by joints or faults." A. B. Thompson, however, in
"Oil Field Development," states that, according to the observations
of C. W. Washburne, "since water has a surface tension of about three
times that of crude oil, capillary attraction exerts about three times the
force on water that it does on oil. As the force of capillarity varies
inversely as the diameter of pore, it is contended that this force tends
to draw water into the finest tube in preference to oil and displaces
contained oil and gas: the result being that oil would be expelled from
fine-grained material like clays into coarse-grained beds like sand."

How thick must a petroliferous shale be to furnish the necessary
amount of oil for a productive field? McCoy states that "the amount of
oil in any producing field could have been derived entirely from shales
immediately surrounding the oil sand. A series of shales aggregating
10 ft. (3 m.) of bituminous sediment, yielding 25 gal. (94 1.) to the ton,
would furnish 17,000 bbl. of oil per acre. Assuming a 25 per cent, ex-
traction, the acre yield would be over 4000 bbl. The average acre yield
in Oklahoma and Kansas ranges from 2500 to 3000 barrels."

Petroleum is probably forming today in many marine waters. Dalton
says it is present "in the mud of the Mediterranean sea-floor between
Cyprus and Syria. ... It was also found in the Gulf of Suez, and in

VOL. LXV. 14.

210 PETROLIFEROUS PROVINCES

each case ammonia and iron sulfide or sulfur occur with the oil." Po-
tonie" showed its presence in the Gulf of Stettin, Germany, and Fritsch
showed that humus is forming rapidly in the salt marsh in the Bouche
d'Erquy, Brittany. In all these cases, the muds are of the black, putrid
type that Potonie* calls sapropel. Why, then, does petroleum not occur
more uniformly in the geologic deposits? Because the hydrocarbons
universally tend to escape into the air or water from which they were
originally taken by the living entities. Muddy waters with the finest
of silts and not too much agitated by currents or winds are the places
where the hydrocarbons naturally may accumulate, because here the
organic fats and oils have great affinity for, and unite with, the minute
clay flakes, and are thus held in more or less solid form and deposited as
kerogen with the shale formations. Evidently, the hydrocarbons can
accumulate and be preserved in large quantities only in areas of argil-
aceous sedimentation. Therefore, in order to accumulate petroliferous
deposits, the waters must have life in them; and the freer they are from
oxygen, the more certain will be such accumulations. On the other
hand, almost all life fails to exist where there is no oxygen, because oxy-
gen is the first essential of nearly all life, and where the petroliferous
materials are gathering in greatest quantities, there the waters are free
of this gas and the bottoms are black and foul putrid muds reeking with
odors. Where, then, does the life come from in these places of hydro-
carbon-gathering? It develops in great abundance in the sunlit, agitated,
and oxygenated surficial areas of the water basins, and after death the
organisms rain into the deeps, where they very slowly decompose, due to
peculiar forms of bacteria existing in the stagnant waters that are de-
pleted of oxygen. Are the surficial waters the only source for the life
that is gathered into the oil shales? No. The life may develop hun-
dreds of miles away from the place of accumulation and be drifted by
winds, or by tidal or even oceanic currents into bays, cul-de-sacs of the
seas, and into the shallow but extensive depressions on the sea bottoms.
The petroliferous deposits are accumulating today in greatest amount in
the shallow waters bordering the lands rather than in the greater depths.

However, not all shales are oil shales. As all geologists know, about
80 per cent, of the sedimentaries are mudstones, and yet petroliferous
shale formations are not common. If forced to guess what percentage
of shales are decidedly petroliferous, I should reluctantly say probably
not more than 10 to 15 per cent. The combination of conditions neces-
sary to deposit an oil shale is present in but few bays or other deeper,
stagnant areas where clay muds are collecting. Therefore the import-
ance to all petroleum geologists of knowing the nature of the sedimentary
formations of the areas they seek to exploit.

The rich oil shales of Utah and Colorado appear to be of fresh-water
origin shallow lakes that existed in Eocene time. We are told that

DISCUSSION 211

they yield on distillation up to 90 gal. (340 1.) of oil, about 18 Ib. (8 kg.) of
ammonium sulfate, and up to 4500 cu. ft. (126 cu. m.) of gas per ton of
shale. 4 This is the only striking occurrence known to me of fresh-water
deposits in North America with an abundance of hydrocarbons. The or-
ganic materials are, in the main, plants and their present condition sug-
gests peat deposits. But we must again point out that the age of the
rocks is comparatively recent (Green River = early Eocene), and that
they have undergone but one slight deformation. Therefore the kerogen
still remains.

Abundance of Life Necessary to Petroleum Gathering. The petroleum
geologist thinks that there must have been a vast abundance of life to
make such great storages of oil as are now still present in the shales.
In this he is undoubtedly correct, but what he does not keep in mind is
the long time it has taken to accumulate the black shales. Accordingly,
the quantity of life necessary to oil accumulation need not be so vast at a
given time as he thinks. On the other hand, he holds that life did not
become abundant enough to result in petroliferous deposits until Middle
Paleozoic time. In this connection it should be said that paleontologists
have long been familiar with an abundance of macroscopic fossils in rocks
dating from the very beginning of Cambrian time and hence from the
beginning of the Paleozoic. The seas ever since that period have been
filled to their limit with life, microscopic and macroscopic, and in con-
stantly increasing variety. What the geologist sees and gets are the
larger fossils; but for every one of these individuals there certainly existed
hundreds of thousands and probably millions of invisible plants and ani-
mals. It is this minute life, and especially the plants, that is so important
in the life cycle, for these microscopic organisms make alive in their bodies
the inorganic materials on which they feed. The micro-plants are the
basis not only of the subsistence of all the animals of the seas and oceans
but, what is equally as important, the accumulation of the hydrocarbons.
In this connection we may also add that the almost pure chemically
precipitated limestones are due to the metabolic processes of minute
plants, the denitrifying bacteria. Accordingly, it is the invisible, and not
necessarily the visible, fossils that have gone to the making of the petro-
liferous deposits of the geologic ages. Most of these forms are short-
lived and propagate quickly and in prodigious quantities; the great
majority pass through the life cycle in from a few hours to a few days or
at most a few months. In this way they make up in quantity what they
lose in individual size.

We know of some animal fossils in the late Proterozoic, and even
though they are as yet few in number, their high organization teaches
unmistakably that there was a host of greatly varying organisms. Of

4 Dean E. Winchester: U. S. Geol. Survey, Bull 641-F (1916).

212 PETROLIFEROUS PROVINCES

lime-secreting algal plants in the Proterozoic, we know vastly more; and
from the course of all organic evolution as revealed by the living world,
supported by the chronogenesis of the geologic past, we can safely state
that at all times, even as far back as the beginning of the Archeozoic as
now known in the oldest of geologic deposits, there must have been an
abundance of life in the waters of the earth. Hence the abundance of
graphite in the Archeozoic and the vast amounts of dark carbonaceous
strata in the Proterozoic. Even so, it is hardly probable that commercial
quantities of petroleum will be found in the rocks of the Proterozoic,
and certainly none at all in those of the Archeozoic, because these very
ancient deposits have either been subjected to frequent deformation, or
because, due to their great antiquity, the volatile hydrocarbons have
long since been liberated into the atmosphere.

The Climatic Factor in Petroleum Making. The question of land
climates probably does not enter at all into the matter of petroleum
accumulation, because it is not in the land deposits that the commercial
quantities of oil are found. As has been said before, the oils occur nearly
everywhere in marine deposits and only rarely in fresh-water ones. This
being so, and as the marine shallow waters of today abound in life,
whether in the warm, cool, or coldest areas, it follows that we may look
for petroliferous formations in almost all continents where the ancient
oceans have spilled over them; and this without paying much attention
to the changing climates of geologic time. On the other hand, as the
greatest amounts of carbon and carbonaceous deposits occur in the
north temperate belt, we should seek here in the main for the petroli-
ferous strata. This does not mean that petroleum is absent in tropical
lands far from it. It only points out that the greater quantities will
not be found in the deposits of former tropical seas, and for reasons to
be setf orth.

Since the previous paragraph was written, there has appeared the sug-
gestive paper by Mehl, already cited, in which he points out that all of
the major oil fields of the world are situated between 20 and 50 north
latitude. Further, that there are no major oil areas within the tropics
or in the southern hemisphere. As the known major oil fields lie between
the present isotherms of 40 and 70 F., he thinks this distribution "does
suggest a distinctly zonal distribution of petroleum in which temperature
may have been an important factor." The question that here arises is, Is
this suggestion of present climatic conditions also true for the times when
the oil was deposited in the strata in which it is now found, remembering
that the oil fields were not made recently but are the accumulations of
hydrocarbons of the seas of the geologic ages? The answer is not at all
in harmony with MehFs suggestion, for we are living in an exceptional
time of stressed climates and marked zonal conditions, while the mean
temperature conditions during the geologic ages were warm and equable

DISCUSSION 213

throughout most of the world. And this is even more true of the tem-
perature of the oceans than of the lands. This being so, much of the
value of Mehl's surmise falls away. On the other hand, it is undoubtedly
true that high temperatures in clear waters and well oxygenated seas
make, as a rule, for complete destruction of the volatile hydrocarbons,
while those of temperate waters in currentless and muddy areas tend to
preserve them. The temperature factor, when high, appears to be de-
structive of volatile hydrocarbon preservation, but in this connection it
should not be forgotten that the seas are far more equable in temperature
than are the lands, and that during most of geologic time the seas were far
more equable in heat content than they are today. This is thought to
mean that the ancient tropical seas were somewhat less warm than they
are now, while those of the polar areas were no colder than the present
temperate shallow-water areas. Corals were common in Alaska in
Silurian and Devonian times, corals and warm-water fusulinids lived in
the Carboniferous in Spitzbergen, and there were magnolias and bread-
fruit trees in Greenland during the middle Tertiary. The writer also
knows that hydrocarbons have accumulated in large amounts in seas
within the tropics, yet seemingly the amount is far the greatest in what
is now the north temperate zone. That this zone has the greatest amount
of petroleum is apparently due wholly to the greater land masses here,
along with the necessary storage strata accompanied by the proper
amount of deformation.

Even if Mehl's suggestion were correct, and we should accordingly
think of next exploiting the temperate region of the southern hemisphere,
we must not overlook the fact that the northern hemisphere is the land
hemisphere, while the southern one is the water hemisphere, and there-
fore has greatly reduced continents. Therefore between latitudes 20 and
50 south we have only the attenuated southern half of South America, the
southern tip of Africa, the southern half of Australia, and New Zealand.
Southern Africa and most of Australia are, furthermore, continental
nuclei or "shields" and therefore have hardly at any time been under the
sea, but in regard to South America the story of marine submergence is
very different. Even now petroleum fields are known in Peru ("one
of the finest oil fields in the world," according to Thompson), Bolivia,
and Argentina. Then, too, the fact should be emphasized that "shields "
are largely made up of pre-Cambrian rocks and therefore are barren of
petroleum.

In regard to Mehl's other suggestion of a "barren equatorial belt,"
I am inclined to believe that he is correct in the main; not, however, on
the ground of temperature and climate, but on that of the tectonic geo-
logic and physiographic conditions of the continents. On the other hand,
attention should be directed to the fact that productive petroleum
fields occur in the Tertiary strata of the tropical zone in the Lake Mara-

214 PETROLIFEROUS PROVINCES

caibo area of Venezuela and in the Caribbean Piedmont of Colombia,
Trinidad, and Ecuador. Further, highly productive fields are those of
the Indo-Malay region, in Java, Borneo, Ceram, and New Guinea. We
know that Africa is a continent that was more continuously high above
the strand-line than any other, and is loaded with continental deposits,
while South America and more especially Australia are not especially
rich in marine sediments, and when these are present they have been
subjected to mountain-making to such an extent that all of the volatile
hydrocarbons have long since vanished into the air or been transformed
into fixed carbon. In the northern hemisphere, most of Asia east of the
Caspian has also been too much the seat of crustal movements to have
much petroleum accumulation in the Mesozoic and Paleozoic formations.
From these observations, it appears that the northern hemisphere will
always remain the greater for favorable petroleum possibilities.

In all that has so far been said, the statements relate in the main to
folded continental masses, but as some most wonderful oil fields, like that
of the Baku area in Trans-Caucasia, are of very small extent, it follows
that many restricted and highly productive fields are possible even in
areas of decided crustal movements, but I should look for such places
only in regions of Cenozoic marine formations, and mainly in Asia.

Paleogeography as an Aid in Locating Oil Areas. The importance of
paleogeography in petroleum geology is as yet but little appreciated.
Foul sea bottoms, where the hydrocarbons accumulate, and sandstones,
in which they are stored, are usually connected with nearness to land.
Their physical characters have to do with shallow seas and more espe-
cially with headlands, off-shore spits and bars, barrier beaches and river
mouths, which divert and from time to time change the currents of the sea.
On the other hand, the open seashores, with their more or less long
"fetch of the winds," are the washeries of the land-derived detritus.
Here the cliff-derived materials are broken up by the waves of the seas
in their grinding mills, and the finer erosion materials of the weathering
lands, brought by the rivers, are assorted and reasserted many times
according to specific gravity and size of grain. The coarsest material lies
on the strand and near the shore, and seaward the material becomes,
broadly stated, finer and finer of grain. All of this assorting and sea-
transporting depends on the size of the waves " kicked up" by the winds,
and the shallowness of the waterways. It makes no difference whether
it is long or short rivers that deliver the unassorted muds and sands to
unagitated and stormless seas, the deposits will be neither petroliferous-
making areas nor good rock reservoirs for oil. If, however, such materials
are delivered into the open and stormswept seas, there will be assorting
according to size of grain, and the sandbars will make headlands behind
which current-less waters will accumulate the hydrocarbons. In all this
we see that as the places of natural hydrocarbon manufacture and its

DISCUSSION 215

future storage are conditioned by the nearness of the shore and the depth
of water, it behooves petroleum geologists to pay close attention to the
discerning of the myriads of constantly changing geographies of the geo-
logic past.

Petroliferous Provinces. We have now defined the essential principles
that underlie, in nature, the gathering of petroleum in commercial quanti-
ties and can next consider the question, What constitutes a petroliferous
province? Clearly it cannot be merely an area that produces oil, because
the word province is significant of embracing things more or less of a kind.
Shall the criterion be whether the area has solid or fluid-gaseous hydro-
carbons? Or whether the strata are dry or wet? Probably neither.
Shall it be the nature of the oil, whether it is light or heavy? Probably
not. Seemingly it should rather be the age and time of deformation of
the strata having oil, combined with their governing structures. In
other words, the classification should express the chrono-orogenetic
origin of the oils. For instance, in the Ohio Basin province, a subprovince
would be the oil fields in the vanishing Appalachian folds along the
western sde of the Allegheny area; another, the eastern Ohio oil fields;
and a third, the Trenton area of Ohio and Indiana. A beginning in
such mapping has been made by Johnson and Huntley in their " Oil and
Gas Production/' plates 91 and 92. However, in the course of time we
shall here, as in other studies, undergo an evolution in our classifications.

In general, Mr. Woodruff's map and plate 92 of Johnson and Huntley
bring out the areas of worth-while exploiting, those of improbable value,
and the regions that can have no petroleum. However, these maps
are so small that other and even more essential features cannot be
depicted; these are the structural trend lines, the periodically rising areas
or "crustal highs," the long-enduring ancient lands and their shore-lines,
and whether the region has strata of more than one era. Of course, all of
these things cannot be plotted on a single map, however large, but until
this is done on a series of maps, we cannot define what are the genetic
characteristics of each petroliferous province and the proper guidance to
its exploitation.

The most important of all geologic problems connected with oil
exploitation, the geologic structures, will not be discussed here. Among
the most important maps necessary for the broad guidance of petroleum
geologists is one to show the "highs" or positive areas and the deforma-
tional structure lines, drawn in symbols according to geologic age, i.e.,
to show the trends of the mountain folds, the many low axes, like the
Cincinnati axis, and the greater fault lines. Such a map, of even a
limited area, would be a prophetic guide to oil exploitation in the region
so mapped.

Can such highly desirable maps be made quickly? Naturally no one
geologist can alone make such maps of the North American continent,

216 PETROLIFEROUS PROVINCES

or even of the United States. They can be made only through coopera-
tion. A special commisson for this work should be organized by the
larger oil companies and a philosophical study made of all of the geologic
problems involved in petroleum discovery. For this we have an example
in the study of the principles underlying copper genesis made by the cop-
per-producing companies of the United States, at a cost of about $50,000.
A similar contribution by the oil companies would go far and might,
even in a few years, make all of the required generalizing maps. But will
the companies believe in these possible solutions, and that they will
undoubtedly lead to a more certain and a more constantly successful
exploitation of petroleum in North America? We have faith in our
prophecy, but will the operators have faith in the prophets?

IRVING PERRINE, Hutchinson, Kans. I think in reading this paper
one should bear in mind its relation to Dr. David White's paper on "Some
Relations in Origin between Coal and Petroleum." 5 In that paper he
discusses the relationship between the percentages of fixed carbon in the
coals, the gravities of the oils, and commercial gas possibilities. His
paper has amap showing certain areas which Doctor White believes to be
hopeless as far as oil and gas possibilities are concerned.

THE CHAIRMAN (C. W. WASHBURNE, New York, N. Y.). I would
like to emphasize one point brought out by Professor Schuchert. The
southern hemisphere has had an exceedingly monotonous geological his-
tory, except the northern border of Africa, the eastern border of Aus-
tralia, and the western and northern borders of South America. In
other parts of these continents there has been little deposition of marine
sediments and very little deformation since Paleozoic time. Therefore
they are not attractive places to the prospector for oil.

There is probably truth in Schuchert's idea that the composition
of the sea water may have had something to do with the preservation of
organic matter. I followed the outcrop of an oil sand about 700 kilo-
meters along the western coast of Africa. The fossils in it are exceedingly
minute, showing that the condition of the sea water was not suitable
for vigorous life, the oysters are not much larger than the head of a lead
pencil, and nearly all forms are dwarfs. In Madagascar there is the
same formation with similar faunal conditions. If the water in semi-
enclosed basins is very salty water, bacteria cannot thrive in it much
better than the molluscan forms of life. This is probably an indication
that the composition of the sea water in enclosed basins may have some-
thing to do with the preservation of fats and waxes in the sediments of
certain areas.

. 6 Jnl Washington Acad. Sciences (Mar. 19, 1915).

NATURE OP COAL 217

Nature of Coal

BY J. E. HACKFORD, LONDON, ENG.

(St. Louis Meeting, September, 1920)

IN SOME research work carried out by the writer, certain results have
been obtained which bear on the fundamental nature and origin of coal
and the relationship between coal and petroleum. Without entering
into a discussion of the details of the experiments, which were conducted
on petroleum and derived bitumens, there are given here, by way of
definition, some of the relations that the writer has established between
certain classes of bitumens of petroliferous origin.

Bitumen. A natural organic substance, gaseous, liquid, or solid,
consisting of hydrocarbons and the oxy-or thionic derivatives of the same,
or of a mixture of all three.

Diasphaltenes. Those portions of bitumens that are soluble in
ether or carbon disulfide, but are insoluble in a mixture of equal parts of
ether and alcohol. Diasphaltenes are produced by the oxidation or
thionization of petroleum oils; they have, as the name indicates, twice
the molecular weight of asphaltenes, into which they are converted when
subjected to moderate temperature. For example, an artificially produced
diasphaltene, which was readily soluble in pentane and ether, was
quite insoluble in either of these solvents after heating for three weeks at a
temperature of 100 C., and was converted into an insoluble asphaltene.

Asphaltenes. Those portions of bitumen that are insoluble in
ether or ether alcohol but are soluble in carbon disulfide.

Asphaltites. Those solid or semisolid natural bitumens that are
composed, for the most part, of asphaltenes or diasphaltenes. A pure
asphaltite 1 would be composed wholly of asphaltenes and diasphaltenes,
but most asphaltites contain small percentages of oil and wax, which have
not yet been converted into asphaltenes; they may also contain a small
percentage of kerotenes, which represent the next stage of the metamor-
phosis of asphaltenes. Among the naturally occurring oxyasphaltites
may be mentioned grahamite; and among the thioasphaltites, gilsonite.

1 The term asphaltite, as recommended by Eldridge (22nd Ann'jal Report, U. S.
Geol. Survey, 1901) is preferable to Dana's term "asphaltum" ("Descriptive Mineral-
ogy," 6th edition, 1906, 1017), for the reason that the naturally occurring represen-
tatives have the generic ending "-ite," e.g., gilsonite, grahamite, etc.

218 NATURE OF COAL

Kerotenes.' Those portions of bitumen that are insoluble in carbon
disulfide. They are produced, by gentle heat, from asphaltenes. It
can be demonstrated experimentally that artificially produced thio-
asphaltenes and oxyasphaltenes, when kept at a temperature of 100 C.
for three months, are converted, with but slight gaseous losses and without
change in sulfur content, into kerotenes. 2 Most of the kerotenes pro-
duced by gentle heating from asphaltenes in this manner were entirely
insoluble in any known solvent, including pyridine, chloroform, and
quinoline.

Kerok. Those portions of kerotenes that are soluble in chloro-
form as well as in pyridine.

Keroles. Those portions of kerotenes that are soluble in pyridine
but insoluble in chloroform.

Kerites. Natural solid bitumens composed, for the most part, of
kerotenes. A pure kerite would be composed wholly of kerotenes, but
the natural kerites generally contain small percentages of one or more of
the following: asphaltenes, diasphaltenes, wax, and oil, whose conver-
sion to kerotenes has not been completed. Of the natural examples,
wurtzilite may be mentioned as a thiokerite and albertite as an oxy kerite.

It has been demonstrated, in the course of these experiments, that
either sulfur or oxygen can play a predominating role in the formation
of these classes of bitumens. If a straight Pennsylvania lubricating oil
with a negligible sulfur content is digested at a temperature of 100,
with either sulfur or oxygen, a darkening in color first takes place (owing
to the formation of thio- and oxydiasphaltenes) ; this discoloration gradu-
ally increases to black with the formation and precipitation of asphalt-
enes, which constantly increase until the whole, except for gaseous losses,
is converted into kerotenes. Similar results have been obtained from
sulfur-free paraffme wax 3 and from natural petroleum oils of all characters;
that is, by oxidation or thionization, accompanied by gentle heat, any
natural petroleum oil may be converted first into oxy- or thioasphaltenes
then into kerotenes. Certain kerotenes are wholly insoluble in any of

* This term is derived arbitrarily from the word "kerogen, " the term introduced
by Crum Brown (Oil Shales of theLothians, Geol. Sur. of Scotland, 1912, 43) to denote
the organic matter present in oil shales, in ordinary solvents, and from which hydro-
carbons are obtained by dry distillation. It was at first proposed to use the term
kerogen, which would be entirely appropriate in this general sense, but it was felt
that some confusion might arise because the word kerogen has become associated
with the bitumen of the oil shales alone.

8 Allen (Pet. Rev., Apr. 26, 1913) and Redwood ("Treatise on Petroleum" 1, 275)
consider the black precipitate formed in paramne wax, when heated with sulfur, to
be carbon, but the writer has demonstrated that this precipitate dissolves entirely
when heated with benzol; it therefore cannot be carbon. The addition of an excess
of ether or pentane to this benzol solution throws down a black precipitate, which is
simply a thioasphaltene.

J. E. HACKFORD . 219

the known solvents, including chloroform, pyridine, and quinoline.
As these experiments progressed, it became evident that bodies closely
analogous to coal were being produced from petroleum in the laboratory
by oxidation, thionization, and gentle heat; this gave rise to certain in-
ferences, which it is the purpose of this paper to state.

RESULTS OF PREVIOUS INVESTIGATORS

The elucidation of the nature of a body, like coal, that is only sparingly
soluble in solvents and cannot be made to yield crystalline derivatives
without previous violent manipulation has naturally presented no little
difficulty. During the past five years a large amount of work has been
accomplished respecting the nature of coal by numerous investigators. 4

These investigations have been mainly along two lines: one was
the examination of solvent extracts, and the other was the study of the
products of low-temperature distillation. The results are scattered
and the inter-relationships have not been fully pointed out. Briefly
stated, the studies of these investigators have shown:

1. That by low-temperature distillation work and by the examination
of solvent extracts, paraffine, olefines, and naphthenes have been isolated
and identified.

2. That the tar distilled from coal at high temperatures is a decomposi-
tion product of coal tars previously formed at low temperatures.

3. That the cellulosic compounds present in coal result in the forma-
tion of phenols upon dry distillation.

4. That the temperature at which coal was formed cannot have
approached 300 C.

RELATION OF SOLUBLE PORTIONS OF COALS AND KERITES

In 1913, Messrs. Clark and Wheeler 5 described experiments in which
a soft bituminous coal, upon extraction with pyridine, yielded a substance
representing by weight a percentage of the original sample, which upon
subsequent low-temperature distillation yielded a mixture of paraffine-
hydrocarbons and hydrogen. In view of his research, the writer sus-
pected that the portions of coal extracted in this manner by pyridine
consisted, largely, of asphaltites and the soluble kerites; accordingly the
following experiment was carried out:

4 D. T. Jones: Jnl. Soc. Chem. Ind. (1917) 36, 3-7; Jones and Wheeler: Chem.
Soc. Trans. (1916) 109, 707, 714; Burgess and Wheeler: Chem. Soc. Trans. (1910)
97, 1917-1935; (1911) 99, 649, 667; (1914) 105, 131-140; Clark and Wheeler: Chem.
Soc. Trans., 103, 1704-1713; R. Maclaurin: Jnl. Soc. Chem. Ind. (June, 1917);
Pictet and Bouvier: Compt. Rend. (1913) 167, 779-781; Pictet, Ramseyer and Kaiser:
Compt. Rend. (1916) 163, 358-361; Fischer and Glund: Berichte (1916) 49, 1469-1471;
and Fraser and Hoffman: Tech. Paper 5, U. S. Bureau of Mines.

6 Chem. Soc. Trans. (1913) 113, 1704-1713.

220

NATURE OP COAL

A sample of 250 gr. of Yorkshire coal was extracted with pyridine. The
bulk of the pyridine was then distilled off under reduced pressure and a
large excess of ether added. A voluminous black precipitate was thrown
down, which was pumped, washed with ether, and weighed. By weight,
it represented 5.1 per cent, yield. This black powder was found to
be 15 per cent, asphaltenes and 84.9 per cent, kerotenes. The 84.9 per
cent, of kerotenes was found to be a combination of 17.9 per cent, of
kerols and 67 per cent, of keroles. We thus succeeded in splitting up
this black precipitate in a similar manner and in similar fractions to those
obtained when working upon natural kerites, as, for example, albertite
and wurtzilite, which gave the following results :

OXYKERITE THIOKERITE
(ALBERTITE) (WURTZILITE)
PER CENT. PER CENT.

Asphaltenes.
Kerotenes. . .

Sulfur

Oxygen

9.0
89.03
Trace

6.97

12.8
81.37
5.83
0.00

The similarity, however, does not end here, for many of the fractions
upon heating melted with decomposition, evolving oil containing (in the
case of albertite) quantities of paraffine wax; while the asphaltenes and
kerols evolved sulfuretted hydrogen. The most sparingly soluble frac-
tion, keroles, do not intumesce to any extent upon heating, as do the
asphaltenes. The solubilities of these substances are exactly the same
as those similar fractions derived from natural kerites, e.g. the asphaltenes

TABLE 1. Analysis of Unfractionated Precipitate

Asphaltenes and
Kerotenes from
Coal
Per Cent.

Natural Kerite, e.g.
Albertite from
New Brunswick
Per Cent.

Kerite in a Trans-
former Sludge
Naturally Pro-
duced by Oxida-
tion of Trans-
former Oil
Per Cent.

Synthetic Oxy-
kerite Prepared by
Passing Oxygen
Through Lubri-
cating Oil
Per Cent.

Asphaltenes and
kerotenes

100

98 03

100

Carbon

73.64

Hydrogen.

4 87

7 1

6 2

Sulfur

1 07

trace

1 58

Nitrogen

2 83

1.4

Oxygen

16 67

6 97

16 97

18 22

Dr. A. C. Michie [Jnl Inst. Elec. Engrs. (1913) 51, 213] gives an analysis of a
sludge deposited by a transformer oil when'used in an auto-starter for a considerable
period. The writer has carried out detailed experiments on a similar sludge. The
original oil in this case was known to be a straight cut oil. The sludge was found to
consist of 10.1 per cent, of oxykerotenes and 79.9 per cent, of oxyasphaltenes. The
oxyasphaltenes, after gentle heating for a month, were converted into oxykerotenes,
portions of which were insoluble.

J. E. HACKFORD 221

both from the coal and from a sample of a natural kerite were soluble in
carbon disulfide, benzene, phenol, nitrobenzene, chloroform pyridine, etc.
but were insoluble in petroleum ether, ethyl ether, ethyl alcohol.

The analysis of the whole unfractionated precipitate is given in Table
1, and, for the sake of clearness, is contrasted with a natural kerite, a
naturally produced kerite, and a synthetic kerite.

RELATIONS OF INSOLUBLE PORTIONS OF COALS AND KERITES

It has been found that, upon prolonged heating, a portion of the
kerotenes becomes insoluble in pyridine or any known solvents; by in-
ference it is believed that most of the insoluble portion of coal consists
of a true bitumen that has been transformed by gentle heating into an
insoluble kerotene, and that a small portion is due to the decomposition
products of cellulose, as shown by the formation of phenol upon dry
distillation. 6 The writer has proved that the kerites experimentally
produced from petroleum yield, at both low- and high-temperature dis-
tillation, exactly the same products as are obtained under the same tem-
perature conditions from the kerites of coal.

THEORY OF FORMATION AND NATURE OF COAL

The following theory is put forward as to the mode of formation and
nature of coal, comparing it at the same time, for the sake of clearness,
with the mode of formation of oil.

First, consider a stratum containing a deposit of either animal re-
mains or marine vegetation. These substances, on decomposition, form
oil and gas which, if contained in a sandy bed, are swept away from their
source by either gravity or water as rapidly as formed, since neither the
animal remains nor the marine vegetation contain cellulosic material
capable of forming a spongelike mass, which would hold the oil in situ
during the decomposition stage.

Second, assume a buried deposit of terrestrial vegetation. De-
composition takes place, resulting in the formation of oil and gas, as in
the case of the marine vegetation. However, owing to the cellulosic
nature of the material and its porous spongy nature, the oil is kept in situ
while decomposition proceeds. Accompanying this decomposition,
there is probably a rise in temperature, which even if not above 100 C.
is quite sufficient, as we have proved in the laboratory, to convert into
kerotenes the oxy- or thioasphaltenes that are simultaneously formed with
the oil. As the process goes on, the kerotenes become more and more
insoluble until they are insoluble in pyridine and quinoline and so remain
as a solid in the spongelike mass afforded by the cellulosic structure of
the terrestrial vegetation.

6 Jones and Wheeler: Chem. Soc. Trans. (1916) 109, 707-714.

222 NATUEE OP COAL

It has been recorded by Hodgland and Lief 7 that the algae on which
they made tests contained from 5 to 13 per cent, of sulfur. It therefore
follows that in those coals that contain algal ingredients in quantity, some
undoubted cases of which White 8 puts on record, a larger amount of thio-
bitumens should be present with a corresponding reduction in the oxy-
bitumens and the cellulosic residues.

According to this theory, the amount of soluble bitumens should be
greatest in peat and should decrease through lignite, sub-bituminous,
bituminous, and semibituminous coals to anthracite, which indeed is the
case. It is interesting to note that where pure kerite deposits have been
found, they have nearly always been mistaken for coal. It took ten
years' litigation to decide whether the New Brunswick oxykerite was coal
or bitumen. Similar instances are given by L. L. Hutchison 9 in the case
of the Jackfork Valley, the Impson Valley, etc. A similar case of a thio-
kerite is a deposit in Nova Zembla, where coal suitable for metal smelting
was reported to be situated near an ore deposit. Samples of this deposit
were forwarded to the writer and yielded on analysis: ash, 0.72 per cent.;
sulfur, 15.54 per cent.; nitrogen, 0.76 per cent. The sample possessed
a bright luster and had the appearance of a bright soft coal. It was,
however, totally insoluble in solvents and on heating gave off little gas.
No oil whatever was evolved; in fact, the sample behaved in nearly
every respect like anthracite. The volatile matter was only 1.8 per
cent. However, from a comparison with certain experiments then in
progress, it was decided that the material was a kerite. A subsequent
geological examination showed the deposits to occur in small lenses in a
metamorphosed deep-sea limestone, which contained none of the depo-
sitional associate of coal and, in fact, confirmed the oil origin of the
deposit. This is regarded as a pure sample of a thiokerite. It is
probably true that certain so-called coals from Colombia that have a
sulfur content of 13 per cent, are simply thiokerites.

The main differences between these so-called coals and true coal rests
in the fact that they possess no cellulosic residue, which upon distilla-
tion can produce phenols, as is the case in true coals. It is conceivable
that a kerite produced from microscopic vegetal remains containing some
cellulose but not in sufficient quantities to act as a sponge would yield
phenols on dry distillation; this would be but another connecting link
between coal and petroleum.

Petroleum oils, such as occur in nature, are clearly not derived from
coal; but given a quantity of vegetal material, petroleum may be pro-
duced under a given set of circumstances if no cellulose is present and
coal will be formed if the vegetal matter contains sufficient cellulose to
form a sponge.

7 Jnl Biol Chem. (1915) 23, 287-297.

8 David White: TJ. S. Geol. Survey Bull 29, 48 et. seq.

9 Oklahoma Geol. Survey Bull 2, 81-89.

DISCUSSION 223

DISCUSSION

W. E. PRATT, * Houston, Tex. Mr. A. W. McCoy some time ago, after
pressing or squeezing, extracted oil with ether from oil-shales which before
squeezing yielded no oil upon extraction. Mr. C. W. Washburne, in
discussing McCoy's results, attributes the formation of oil in the shale
to heat induced by pressure rather than to pressure directly. This seems
to be McCoy's idea also; that is, the ether-soluble content increased upon
the application of heat (through pressure). Mr. Hackford finds that
similar materials which have a certain ether-soluble content suffer a
decrease in ether-soluble content through the direct application of heat.
There is an apparent contradiction in this situation which may be
explained, perhaps, by assuming that heating "cracked off" new ether-
soluble combinations in each set of experiments, but that these new
compounds were allowed to escape in Mr. Hackford's work, leaving the
residual material less ether-soluble, whereas Mr. McCoy retained
the cracked products in the original material until he extracted them
with ether.

DAVID WHITE, Washington, D. C. The theory that beds of coal are
bituminized from outside sources is, I believe, to be regarded with great
skepticism. That the bitumens, so called, are generated in the process of
the evolution of the coal bed itself appears more tenable, and will, I
anticipate, be ultimately proved.

The distinction between the origin of the normal series of coals, namely
from terrestrial or vascular vegetation, and of the oil-shales, from aquatic
and largely cellular plant debris, is emphasized very properly by Mr.
Hackford. Putting the distinction in terms related to the chemical
distinctions, coals may be said to be characterized by ingredient carbo-
hydrates, while oil-shales embrace waxy, resinous, gelatinous, and other
plant products.

E. DEGOLYER, New York, N. Y. Since it had always been held that
the oil found in the coal mines of England was distilled from the coal, it
became extremely important to prove whether or not it was a coal-tar
distillate or true petroleum. This was Mr. Hackford 's contribution to
that work.

He has given also some interesting suggestions as to the origin of
Mexican oils and the Gulf Coast oils. His theory provides for the sulfur
content of the oils of coastal Texas and Louisiana, the Isthmus of Te-
huantepec District and the Tampico District. The Tampico area is not a
salt-dome region, but its oils have a high sulfur content.

I have not paid much attention to oil-shales, but I have observed that
the English chemists and geologists, who are best acquainted with oil-

* Chief Geologist, Humble Oil & Refin. Co.

224 NATURE OF COAL

shales and not so well acquainted with petroleum as their American
colleagues, think that the oil-shales are derived from petroleum; the
petroleum came first and the oil-shales as some sort of secondary product.
American geologists and chemists seem to argue in the other direction.
We are better acquainted with petroleum than with the oil-shales and
there is a marked tendency at present to regard petroleum as resulting
from the natural distillation of oil-shales. Both groups are trying to
explain the known by the unknown.

REINHARDT THIESSEN,* Pittsburgh, Pa. (written discussion f). The
writer agrees with three of the conclusions drawn from investigations of
coal by means of solvent extracts and low-temperature distillation, but
does not fully agree with the conclusion that the cellulosic compounds in
coal result in the formation of phenols upon dry distillation. He believes
that there is not enough proof to warrant so definite a conclusion. Ex-
perimental proof does not indicate that phenols result entirely or ex-
clusively from the cellulosic derivatives of coal. Only relatively small
amounts of tar are formed in the dry distillation of cotton; according to
Cross and Bevan, 10 this tar is composed of water, furfurol, phenols,
liquid and solid hydrocarbons; according to Tollens 11 it also contains
allyl alcohol and creosote. Schwalbe' 2 questions whether any of these
products are formed from pure cellulose; he believes that they are dis-
tillation products of the substances associated with the cellulose. Why
should the cellulosic derivatives in coal be considered the source of the
phenols when the plants, as a whole, contain so much and so many
phenols?

The writer has given considerable time to the study of the origin and
constitution of coal and allied substances by examining thin sections
under the microscope which has given abundant proof that the important
coal beds have been formed from woody plants, trees, and shrubs, rather
than from herbs, grasses, mosses, and algse or similar organisms.

The mode of deposition and formation of the peat bogs that formed
the present coal seams may be studied by examining the various types of
existing peat deposits. It is probable that each kind of coal seam has its
analogous deposit in present deposits of peat. For example, the ordinary
bituminous and subbituminous coals and lignites in the arboreal-peat
swamps; the cannel and boghead coals in the quaking bog or marsh; and
the bituminous or oil-shales, in the open bog.

A study of arboreal-peat deposits, such as the Dismal Swamp and

* Research Chemist, U. S. Bureau of Mines.

t Published by permission of the Director, U. S. Bureau of Mines.

" C. F. Cross, E. J. Bevan, C. Beadle: "Cellulose," 69, 1895.

11 B. Tollens: "Handbuch der Kohlenhydrate," 1, 233, 1891.

12 Carl G. Schwalbe: "Die Chemie der Cellulose," 33, 1911.

DISCUSSION 225

those found abundantly in Wisconsin and Michigan, shows that they are
composed of semi-decayed logs, branches, twigs, and stems. These are
embedded in a general debris consisting of semi-decayed chips or frag-
ments of wood and bark, leaves, cuticles, rootlets, small twigs, mosses,
lichens, in all degrees of fragmentation, and of spores, pollens and resins
which, in turn, are embedded in an attritus derived from all kinds of
plant parts and the whole mass has been transformed into peat by means
of putrefying organisms. The resinous contents of the woody parts are
still in place.

There is only a relatively short step from peats to the lignites. A
description of the composition and the constituents of peat will do equal-
ly well for that of lignite, except that in the transformation from peat into
lignite, coalification process has taken place and the mass has been greatly
compressed and hardened.

The subbituminous coals are formed from the same or similar
kind of plants and plant products laid down under the same or similar
conditions, and often during the same time as the lignites. In certain
cases a lignite bed and a subbituminous coal bed are parts of the same
deposit, but the transformation, or coalification, has gone further and the
mass has been further condensed and compressed in the one part than
in the other. The ordinary bituminous coals form but another step
in the chain of the transformation of peat into coal. The chemical
nature and structure must necessarily differ widely from those of peat or
lignite for the coalification process has been carried on for a longer period.

By far the largest part of coal is derived from logs, stems, branches,
twigs, and roots, which are represented in the coal by the black glistening
band of varying thicknesses and widths. The thicker and wider bands
represent logs and stems, while the thinner delicate black glistening
bands represent smaller chips or fragments. The duller bands between
these represent the general debris, which consists of coalified fragments of
all kinds of woody plant parts and smaller fragments of wood, bark,
leaves, petioles, cuticles, and macrospores, and an attritus. The attritus
consists of finely macerated coalified plant degradation matter, spores,
pollens, resins, and cuticles.

The bituminous coals are generally of the Paleozoic age, when the
.plants were chiefly Calamites, plants belonging to our modern horsetails;
Lepidodendrons, and Sigillarias, plants belonging to our modern club
mosses or lycopods; and secondarily of Cycadophytes, plants belonging
to the modern Cycads; Cordaites, trees belonging to the recent conifers
and ferns. The lignite-forming plants consisted chiefly of conifers.
This difference in the kind of plants does not necessarily account for the
chemical differences since the chemistry of plants is, in general, quite
the same.

The cannel and boghead coals are composed largely of attritus,

VOL. LXV. 15.

226 NATURE OF COAL

which consists chiefly of spore matter, some resinous matter, and finely
divided plant degradation matter, of which the spore matter usually
forms by far the largest part; they usually contain a large amount of
inorganic matter. Anthraxylon is but sparingly present in the boghead
and cannel coals. Beds of ordinary coals often include layers that are in
every respect like cannel coal. When such layers are thick enough to be
easily noticed, they are called bone or cannel coal.

The oil-shales are in many respects similar to the cannel coals; the
chief difference is in the higher mineral contents of the oil-shales. Tor-
banite is called both a boghead coal and a rich oil-shale; before
petroleum was discovered it was extensively distilled for oil.

Oil-shale, examined with the microscope, is seen to contain the same
kind of objects as cannel coal but present in different proportions. In
many shales, spore-exines form the largest part of the organic matter; in
others, spore-exines and plant degradation matter are present in about
equal proportions; in some, few or none are recognizable.

As deposits that contain constituents very similar to those contained
in oil-shales are being laid down at the present time, much may be learned
through their study. Such deposits are being laid down in depressions
without proper drainage containing a rather shallow body of water.
The water is not deep enough to prevent vegetable growth, but it is too
deep for a woody plant growth, consequently a luxurious aquatic plant
and animal life is sustained. As long as this area is maintained, the
dead plant and animal matter largely decays and disintegrates. Certain
parts of the plants and certain plant products, though, resist decay;
pollen grains, spores, resinous matter, waxes, cuticles, certain woody
parts, etc., are among these. But even in the decay of the more delicate
parts a resistant degradation matter is left. All of these, together with
the mineral matter of the plants and that blown into it as dust and washed
into it by streams, form a slimy ooze at the bottom, which on drying has
much the appearance and consistency of art gum. In many respects
it is similar to peat. The constituents are of the same kind as those of
the oil-shales.

Plants consist mostly of cellulose and its modified form known as
lignocellulose; unfortunately, too little of the chemistry of this substance
formed through decay is known. After wood has partly decayed, as
the wood in peat, it is no longer cellulose nor lignocellulose; nobody knows
what it is. In addition to lignocellulose, plants contain resins, gums,
waxes, fats, oils, tannin, proteins, chloroplasts, various kinds of alcohols,
ketones, aldehydes, acids of the aliphatic series; and phenols, quinones,
alcohols, aldehydes, ketones, acids, turpenes, camphors, glucosides, tan-
nins, alkaloids, and others of the aromatic series. Many of these are stable
compounds and resist decay; others have resistant radicles and, after the
end products or side chains have been torn away through putrefying and

DISCUSSION 227

coal-forming agencies, leave a resistant substance. Particularly significant
in this respect are the heterocyclic and the cyclic plant compounds and
their derivatives. All organic plant substances are organic, or carbon,
compounds either in a straight carbon chain, a carbon ring or rings with
side chains or end groups, and all are capable of losing their side chains or
end groups and leaving a hydrocarbon compound. During the trans-
formation of plant substances into coal, cannel coal, or oil-shale, there is a
reduction reaction and the organic compounds tend to form hydro-
carbons ; geologists term this deoxygenation. This process also constitutes
what is generally termed bituminization. But we have no clear idea of
what bituminization is nor what constitutes a bitumen.

We have some knowledge as to what is going on in the transformation
of the plant substance into peat. Many of the organisms bringing about
fermentation and putrefaction have been isolated and their activities
studied and their products have been analyzed and are known. But
after the deposits have been covered for years, and the activities of the
organisms have ceased, changes continue. What these changes are and
how they are brought about should be a fruitful field for research.

C. E. WATERS,* Washington, D. C. (written discussion). The paper
is of interest because of its bearing on the behavior of petroleum oils when
used as lubricants in internal-combustion engines. Up to 90 or 100 C.,
petroleum oxidizes very slowly in the dark; at 200 C. and above, the oxi-
dation may be very rapid, with the formation of compounds that are pre-
cipitable by the addition of petroleum ether. "Sludging" tests for trans-
former oils, Kissling's tar- and coke-forming tests, and the writer's
"carbonization" test are based on this fact.

The rate of oxidation is accelerated by increasing temperature and by
the presence of alkalies, iron oxide, sulfur and sulfur compounds, and the
oxidation products. Filtration through bone black or fuller's earth
largely removes these oxidation products, which are in solution, or per-
haps more correctly in colloidal suspension, in the oil.

The precipitates thrown down by petroleum ether are almost com-
pletely soluble in benzene. They are usually dark brown and fine grained ,
so that they form porous lumps after the oil is washed out and they are
dried in an air bath. Some of the precipitates are granular and some,
after drying, are jet black with a coaly luster and look as if they had been
fused, or at least sintered together, during the drying.

Some chemists reject the idea that the carbon deposits in an engine
can be formed by partial oxidation of the oil, with formation of asphaltic
matter. They regard cracking and incomplete combustion, both of which
reactions deposit carbon, as the causes. But these deposits, after the
removal of the adhering oil by extraction with petroleum ether, contain

* Chemist, Bureau of Standards.

228 NATUJRE OF COAL

much soluble matter. Benzene extracts several per cent. Following
this pyridine gives a dark-brown solution that filters easily. Five per
cent, caustic soda yields a dark-brown solution that is difficult to filter,
evidently on account of its colloidal nature. When the residue on the
filter is washed, enough runs through to render the filtrate turbid. The-
addition of sodium chloride makes caustic-soda solution easier to filter
because the colloids are partly precipitated, as is shown by the lighter
color of the solution.

VALUE OF AMERICAN OIL-SHALES 229

Value of American Oil-shales*

BY CHARLES BASKERVILLE, f PH. D., F. C. S., NEW YORK, N. Y.
(Chicago Meeting, September, 1919)

SHALES containing "kerogen," or bituminous matter, which on destruc-
tive distillation yield oily and tarry matters resembling petroleum are
here designated as oil-shales. They differ from oil-bearing shales from
which petroleum may be obtained by so-called mechanical means. The
educts obtained by the destructive distillation resemble some or all the
varieties of petroleum, depending on the character of the shale and
the mode of treatment. Some shale oils have a paraffin base, some
an asphaltic base, or a combination; some run high in sulfur compounds.
The methods of refining and cracking, therefore, are essentially the same
as are used in refining petroleums.

In 1860, in this country, over fifty companies were successfully dis-
tilling various natural bituminous materials for the production of " coal
oil," used for illuminating purposes. The discovery of petroleum and the
failure of these companies to save and utilize the valuable byproduct,
ammonia, brought about their inevitable doom. Prior to that time,
more or less successful efforts were made to produce from the shales
of Scotland oils for illuminating and heating purposes. Competition of
native petroleum from the United States early eliminated some of these
companies and with the entrance of oil from the Russian and other fields
into the world's markets, the Scottish oil-shale industry underwent
serious and trying experiences until, in 1916, only four (Scottish) were
paying concerns. These survived only through energy and the appli-
cation of skill in saving valuable byproducts.

A few companies have successfully operated in France and New
Zealand. The Canadian Government showed active interest in the New
Brunswick shales, which exist in quantity and are more valuable than the
Scottish shales. The retarded development of that valuable asset of
the Province of New Brunswick was most unfortunate, especially when
the product was so much needed in the prosecution of the war.

The economic success of a shale-oil industry depends on the follow-
ing factors :

* This paper was presented by request at the Denver meeting of the Institute.
Delay in its publication gave the author an opportunity to revise that part which had
to do with the prosecution of the war. However, the fundamental features concern-
ing the economic development of an important natural resource are given as indicated
in the original communication.

t Professor of Chemistry and Director of the Chemical Laboratories, College of the
City of New York.

230 VALUE OF AMERICAN OIL-SHALES

1. The shale, on distillation, must yield an oil simulating petroleum
in character and composition. The distillation is carried on in retorts
variously designed, preferably to make the process continuous. Nor-
mally the shale, in pieces of suitable size, is fed into a retort near the top of
which the shale is subjected to a fairly low lateral heat. The products
of distillation thus produced are swept out by a current of gas produced
below. As the shale passes through the retort it is subjected to a more
intense heat, which brings about the distillation of the heavier products.
The carbonized residuum then comes into contact with regulated blasts
of steam (and air), which generate water (or producer) gas. This gas
passes through the cooler parts of the retort and assists in sweeping out
the products evolved at the lower temperatures. The entire gaseous
product passes through suitable condensers to remove" the oils, paraffin,
tar, etc., and through scrubbers to remove the ammonia; and the residual
gas is then burned in annular chambers to provide the lateral heat re-
ferred to. The ash, often more than 50 per cent, of the original shale,
is automatically removed from the other end of the retort by various
mechanical devices, somewhat similar to the Mond-Lymn sealed gas
producer. The Scottish practice involves four retorts in a unit, which
units are multiplied into banks. A unit, four retorts, handles about 10
tons of shale per day of 24 hr. The condensers and scrubbers resemble
those of ordinary gas (coal and water) works. In other words, there is
no great necromancy in distilling oil-shales and refining them, as some
might have one suspect or believe.

2. The shale must yield oil in such abundance as to pay the costs of
mining and treatment, or the character of the oil must be such that it pos-
sesses unusual value; for example, a high percentage of paraffin, or a
notable amount of ichthyol.

3. Since the last-mentioned conditions are comparatively rare in
the oil-shale industry, a valuable byproduct is essential to carry the
burden of mining and treatment. The combined nitrogen, which is
largely converted into ammonia in the distillation, has been the salvation
of the few surviving Scottish companies and must be an important con-
sideration in any shale-oil industry anywhere.

4. Assuming adequate oil educts (30 to 60 gal. per ton of shale dis-
tilled) and a supporting ammonia output, the oil shale must be in ample
quantity and so situated as to be mined in the cheapest manner. Ade-
quate water supply is essential for condensing and other purposes for the
crude-oil works.

5. An adequate supply of sulfuric acid for the absorption of the am-
monia is essential. If 30 Ib. of ammonium sulfate were obtained per
ton of shale, it would call for some 25 Ib. of sulfuric acid per ton of
shale treated (round figures are used), or 12,500 tons of 92 per cent,
sulfuric acid for every million tons of shale treated. A 50,000,000 bbl.

CHARLES BASKERVILLE 231

annual production would thus call for 625,000 tons of sulfuric acid, which is
no mean quantity. An annual increase of over 800,000 tons of ammonium
sulfate from such an operation would materially affect the market for
that substance. However, the product has a variety of valuable uses,
not only in agriculture and chemical manufacturing, but in refrigeration.

6. As observed, the character of the shale and the mode of distilla-
tion determine tfre quality of oil obtained. Although the process and
its products are simple in outline much unknown along these lines awaits
investigation. It is known, however, that different modes of treatment
yield crude oils of entirely different composition. Furthermore, the
field-test methods practiced, while giving valuable empirical information
as to the character of the shale under a uniform system, fail utterly to
tell the proper procedure to be followed to secure the best values. Labo-
ratory methods come nearer the truth, but the only truly accurate way
is by commercial tests in full-sized units.

The character of the shale, whether caking or non-caking, is important
in determining the proper mode of treatment. For the present we may
dismiss consideration of the "caking" shales, which really involve
methods for treating cannel coals, and consider only the non-caking;
that is, the "curly" (massive) and "paper" shales. Curly and slicken-
sided shales are characteristic in Scotland; these and paper shales are
found in Canada. The paper shale appears to predominate in certain
parts of the United States.

Much discussion has arisen as to the best method of treating the shales
found in very large quantities in Colorado, Nevada, Utah, and Wyom-
ing. 1 It has been claimed that the Scottish practice is not the best for
our American shales. To be sure, a successful industry in one environ-
ment may fail when transplanted, but experience has led me in. a new
field to adopt the best practice of a given environment and then allow
it to evolve with the changed conditions. There is reason to believe that
this procedure will be pursued by the Bureau of Mines, which is expected
shortly to erect a commercial experimental plant in the field. Initiative
has already been shown by some companies, whose engineers, as a result
of research, have erected small experimental plants.

Several processes have been devised to strip the oil of its gasoline as
fast as it is produced. Some attempt to fractionate even further (light
oils, fuel oils, and residuum) during production; this line of attack does
not commend itself to me. The crude oil, stripped of gasoline, will
have an inferior value and will still require refining, as will also the gaso-
line thus stripped. One of the most noteworthy processes is based on
a circulation of gas, which, after scrubbing, passes back through the
distilling mass, thus taking advantage of the vapor pressure of the dis-

1 See the reports of the Bureau of Mines and the Geological Survey of the United
States, especially Bull. 641-F by Winchester (1916).

232 VALUE OF AMERICAN OIL-SHALES

tillation. The distillation is thus accomplished at a much lower tempera-
ture, with a saving of fuel and a larger yield of valuable products.

Whatever process may be proved to be most suitable, and no doubt
several may be shown to possess distinct advantages, it must be re-
membered that the production of shale-oil in the West is not so much a
problem of mining as of manufacturing. Indications point to the easy
application of the simplest mining methods to this field. The mining
question has been dealt with in reports by Winchester, 2 Hoskins, 3 and
others, especially George, 4 whose advice in regard to oil-shales in Colo-
rado in particular should be sought.

The production of petroleum in the United States is not keeping pace
with consumption. This condition, while it was accentuated by the
war, is not an actual outgrowth of it. The extension in the use of the
gas engine and the development of oil-power energy producers have
caused notable increases in the consumption of liquid fuel. The rich
Mexican fields may supply the deficit in production within the United
States and the untapped oil reservoirs of South America may yet flow
to our refineries, but the difficulties of transportation and the establish-
ment of satisfactory trade relations, which are not unsurmountable, im-
press one with the importance of self-containedness, especially in con-
nection with a raw material on which so much of our national industry
depends.

The annual production of crude petroleum within the United States
for 1918 is estimated at 300,000,000 bbl. This will require a material
addition to keep the 477 refineries in operation up to their capacity of
490,000,000 bbl. annually. Hence new oil fields or new sources of crude
oil, or both, must be developed. Rumors of prospecting in some new
fields and of active attempts to open up new pools in old oil regions are
current. War demands, which obtained and are likely to continue for
some time, and the lack of a universal carburetter inhibit the use of such
substitutes as benzene and ethyl (grain) and methyl (wood) alcohols
for the time being. To meet the deficiency, within recent months at-
tention has been directed acutely to the enormous latent fuel-oil resources
dormant in American oil-shales.

Recently my attention has been drawn to a variety of flamboyant
advertisements in connection with the shale-oil industry, which were
so misleading that I hope the Institute will take adequate steps to safe-
guard, as well as foster, a promising industry. It is no business for an
individual who expects quick returns. Too much stress cannot be laid
upon the fact that it is a manufacturing industry requiring ample capital
for large operations with the very best of technical skill. With these and
with patience, the enormous resources now dormant in American oil-
shales may be developed into a great and profitable industry.

2 Op. cU. ' ^tate Geologist of Colorado.

* Min. & Sci. Pr. (Apr. 13, 1918).

DISCUSSION 233

DISCUSSION

ARTHUR L. PEARSE, London, Eng. (written discussion). In the
last paragraph Professor Baskerville correctly sums up an important
position. The paper was probably written some months ago, as is
indicated; if it were written today he would have further emphasized
these conclusions. The oil-shale is a great industry, has been for many
years, and bids fair to become one of the most important. This industry
and its twin the carbonization of coal are the most important
unorganized industries in the world today.

We are not precise enough when we talk about the Scotch shale-oil
practice. If reference is made to the system of retorting that reached
an assumed standard some 10 yr. ago, I would say that no one would
build such retorts today; but they are good enough to wear out and
there are more of them in Scotland than there is shale to keep them
going. If the reference is to the Scotch system of treating the oil,
evolved out of much experience and generally adopted as standard 6 yr.
ago, I would say that this method has been replaced by fractional dis-
tillation and cracking plants. The old Scotch re tor b is not the best to
use on either American or any other shale. The adoption in the latest
English plant, of which the first unit is 1000 tons daily, of an entirely
different retort proves this.

Principally owing to better practice, evolved out of work on the car-
bonization of volatile coals and other hydrocarbons, to say nothing of
shale, we have learned a great deal. With the exception of the cases when
the carbonized residue is required in such shape as metallurgical coke,
for instance, and for which the coal or material is primarily treated, all
the older methods of carbonization in ovens, intermittent or continuous
verticals, etc., and where mass carbonization is adopted, are obsolete.
By mass carbonization is understood the heating of a body of material,
the particles of which are in close contact with each other, in contra-
distinction to a condition in which each particle is unconfined. Mass
carbonization involves the passage of the heat units from the wall of the
retort into the center or through the charge; as this action proceeds, it
sets up the best heat screen with the corresponding costly results. This
is why the consumption of heat is so great in coke ovens or vertical
retorts. The act of carbonization under proper conditions is almost
instantaneous. The aim of modern designers is to approximate this
condition. It has been proved that, provided the gases are properly
taken care of, the product is better and there is more of it. Besides, if
gasoline, or motor spirit, is a desideratum, the faster the carbonization,
the better the spirit, for the destruction of olefines is less, especially at
low and similar temperatures.

It must not be forgotten that the whole tendency of destructive dis-
tillation, or as an authority has recently named it, "constructive" dis-

234 VALUE OF AMERICAN OIL-SHALES

tillation, is toward lower temperatures. In the United States 700 F.
is used by one plant as its standard; while in England 600 F. is used
with the best of results; but these temperatures necessitate other consid-
erations if a reasonable recovery of ammonia is required.

The adoption of the principles mentioned have resulted in low first
cost per ton-day for retorts because the "through put" is greater owing
to better heat application. The amount of heat used is one-third less
and the quality of the product is better, for the gases are withdrawn
nearly as and when evolved.

While the retort has been the most serious question to many, the
disposal of the gases has also been troublesome, especially where there is
a shortage of water. The ponderous and, usually, leaky air and water
condensers formerly so universal have been replaced, even in Scotland,
by systems of fractional condensation, whereby the products are taken
down in nearly the fraction or fractions desired. The cost of this
section of a plant is practically cut in half and so is the trouble and
expense of running.

A big through put, or divisor, is essential to the best plants; the neces-
sary capital involved, even for a Scotch plant, was enormous, and the
plant was very complicated. Today the cost of a modern plant can be
reduced to 70 per cent, of what it would have been 2 yr. ago and at least
the same reduction can be made at the operating end.

Although a great deal has been done toward cheapening and simpli-
fying the process of carbonization, Professor Baskerville is right when
he says that it is an industry requiring capital and skill. There are
many angles and many economic conditions to be considered; not the
least of which is " distribution. " Notwithstanding all these, it may now
be safely assumed that it is quite as easy to distil oil from shale as to
drill for and distil oil for its products, and on the whole it will be quite as
profitable commercially.

E. A. TRAGEB, Bartlesville, Okla. I have distilled something over
800 or 900 samples of western oil shales and find that it is possible to
get different products by different types of distillation. I have also
found that by the same method of treatment the shales are divided into
different groups. One type of shale tends to yield gas almost entirely;
the majority of them yield mostly oil; while there are some that give a
good yield of both gas and oil. This summer I found a type that by
dry distillation will yield B. S. almost entirely.

THE CHAIRMAN (C. W. WASHBURNE, New York, N. Y.). What
conditions do you find give the best results in distillation?

DISCUSSION 235

A. W. AMBROSE, Washington, D. C. The matter of heat control is
perhaps one of the biggest factors in determining the quality of the
different byproducts.

E. A. TRAGER. You can produce all gas and no oil from any shale by
heating too rapidly, but as near as it is possible to tell, by a uniform
method of distillation the different shales will divide themselves into
different groups, this division being based on the resultant products.

A. W. AMBROSE. Did you try any experiments by grinding shales to
different sizes?

E. A. TRAGER. Yes; but the size does not seem to affect the
product. We tried everything from J in. to Moo i n - mesh and
the product is very much the same. The method of heating is the im-
portant factor.

CHAIRMAN WASHBURNE. It is evident that this matter of distil-
lation of oil shales is something for our grandchildren, possibly our great-
grandchildren, but let us hope that scientists will begin to study the
problem so that the next generation may have some good out of it. I
believe that there has never been any gasoline or kerosene of good com-
mercial quality produced from our Western oil shales in any quantity.
The best American shale, with the best method we have, would take too
much sulfuric acid in treatment. What little first-class oil would be
left after the treatment would not pay for the cost of the operations.

E. A. TRACER. I found some oil shales that yield from 30 gal. to
60 gal. per ton, which on distillation will yield about 23 per cent, gasoline
and 33 per cent, kerosene; this was treated with H 2 SO4 and the loss
wasn't very great. The samples of shale which contain only a small
amount of oil yield a low grade of oil; while at the same time, the better
shales will yield more oil and contain a larger percentage of light con-
stituents. The best shales which have been found to date come from
Colorado. The gasoline is apparently of very good grade but the great
objection is the offensive odor it is very undesirable just what it is, I
don't know.

CHAIRMAN WASHBURNE. Does that last remark apply to most oil
shales in Colorado or to just a few samples?

E. A. TRAGER. It applies to all Colorado shales. We have studied
quite a number of samples and in every case the shale that yields a low
amount of oil will yield a heavy gravity oil. Some of the crude shale oil
is quite light; the first of the yield looks somewhat like the old fashioned
kerosene. It is only the odor you will have to contend with.

236 VALUE OF AMERICAN OIL-SHALES

R. A. SMITH, Lansing, Mich. Mr. H. A. Buehler recently told me
that a new type of retort for coke manufacture has been developed by
G. W. Wallace of the St. Glair County Gas Co. of East St. Louis, 111.
This retort has been found to be especially adapted to oil shales. It is
entirely different from the standard types in use at the present time.
Coke is produced in 4 hr. and the treatment of oil shales is completed in
about the same time.

INDUSTRIAL REPRESENTATION IN THE STANDARD OIL CO. (N. J.) 237

Industrial Representation in the Standard Oil Co. (N. J.)

CLARENCE J. HICKS,* NEW YORK, N. Y.

(Lake Superior Meeting, August, 1920)

THE labor policy of the Standard Oil Co. (New Jersey) is founded
first of all on paying at least the prevailing scale of wages for similar
work in the community; on the eight-hour day at the refinery, with
time and one-half for overtime; one day's rest in seven; sanitary and
up-to-date working conditions; just treatment assured each employee;
opportunity for training and advancement; payment of accident benefits
beyond the amount prescribed by the State compensation law; health
supervision by a competent medical staff; payment of sickness benefits
after one year's service; cooperation with employees in promoting thrift
and better social and housing conditions; and assurance of a generous
annuity at the age of 65, guaranteed for life after 20 years of service.
Most of these features have been a part of the company's policy for
many years, but it is only during the past two years that the cooperation
of employees in determining these matters has been definitely assured
through industrial representation.

Industrial representation, in the Standard Oil Co. (N. J.), is a principle
rather than a procedure. It is built upon the belief that personal as-
sociation of those interested in any problem leads to a mutual under-
standing and a fair decision as to what is right. Fully believing in
this principle, representatives of employees and representatives of manage-
ment evolved a simple plan, the basis of which is that it gives every
individual employee representation at joint conferences on problems and
fundamental principles affecting all those interested in the industry.
It is based on cooperation, not antagonism; its operation makes per-
fectly clear both to management and to employees that their interests
are identical, and not at variance with the interests of the stockholders,
and that mutual understanding and cooperation insure progress and
success for all. Furthermore, experience has definitely shown that
representatives of the employees are not only alert for the employees'
interests but are as keen as the representatives of the management
in determining and insisting upon fairness to the employer.

Though the plan has been in operation nearly two years, it is an
experiment, in that, being based on a principle rather than on cut-and-

* Executive Assistant to the President, Standard Oil Co. (N. J.).

238 INDUSTRIAL REPRESENTATION IN THE STANDARD OIL CO. (N. J.)

dried formulas of procedure, it is still subject to change and improvement
It has proved to be equally applicable in a refinery, where thousands
of men are assembled, and in the sales department and the producing
field, where men are scattered in small groups over a wide territory.
It is also in operation in several subsidiary companies. This adjustment
to diverse conditions is possible because hard-and-fast rules were avoided,
in the belief that the human element must play an important part.
Therefore the plan, to a large extent, has been permitted to build itself
through experience, and trial.

The plan was brought into operation by an invitation to employees
to cooperate in maintaining the company's established policy for fair
treatment in matters pertaining to wages and working conditions.
This invitation outlined a simple method by which the employees,
by secret ballot, might elect from their own number men in whom they
had confidence to represent them in conference with representatives
of the management. At the first joint conference a brief plan or agree-
ment was evolved, which provided that adjustment of wages, including
matters affecting working hours and working conditions, shall be made
in joint conference between the employees' elected representatives in
the division affected and the representatives of the company. From
the beginning, the plan stipulated that no discrimination shall be made
by the company or its employees against any employee on account of
membership or non-membership in any church, society, fraternity, or
union. Agreement was made as to offences for which employees may be
dismissed without notice and also as to the offences for which an employee
should be warned or suspended. Further, each employee was guaranteed
recourse against unjust treatment or unfair conditions by means of a
definitely prescribed method through which he, personally, or his repre-
sentative, may appeal his case to joint conferences of employees' and
management's representatives and, if necessary, up to the highest officers
of the company.

The joint works (or plant) conferences are held at regular intervals
to consider all questions relating to wages, hours of employment, work-
ing conditions, and any other matters of mutual interest that have not
been satisfactorily settled in the joint division conferences. These
joint division conferences meet whenever needed to discuss and adjust
matters within the smaller confines of a division. Many problems never
go beyond the joint conference, unless the problem develops into one
that concerns other divisions. In case any matters were to come up
on which the joint works conference could not agree, they would be
referred to the Board of Directors for final decision. But as yet not a
single case has been referred in this manner. The decisions of the joint
works conference, when they involve serious matters, such as a general
increase in wages, are subject to the approval of the Board of Directors.

DISCUSSION 239

At the inception of the plan, a basis of representation was determined
upon that would allow one employees' representative to be elected by
approximately 150 employees, with provision for a minimum of two em-
ployees' representatives from each division. In extending the plan to
other departments of the company, such as the producing field and a
refinery where fewer employees are required, this basis was amended
to meet the conditions obtaining in that field. On this point two es-
sentials have been borne in mind: First, that an elected representative
must not have more constituents than he can easily keep in touch with ;
second, that the joint conferences must not be so large as to be unwieldy
at times when important discussion and decisions must be had. Ex-
perience has shown that there are many advantages to be gained by
personal contact of employees' representatives and managements'
representatives, and therefore full joint conferences are preferable* to
numerous smaller subcommittees.

Entirely apart from the industrial representation plan, but equally
established as a policy in the Standard Oil Co. (N. J.), is a method of
protection for employees and their families. This is attained in several
ways: Group life insurance covering, at the company's expense, every
employee after one year's service, affords some financial resources to
dependents in case of death of an employee a provision that was greatly
appreciated during the influenza epidemic of 1918-19. There is a fully
equipped and competently manned medical department to look after the
health of all employees; and there is provision for half pay during a
period of sickness. An annuity plan provides for employees who retire
after 20 years of service or who are incapacitated after even shorter
service. These forms of financial security are considered by the company
as being good business and therefore are maintained solely by the
company's funds, not by either voluntary or involuntary assessments
on the employees.

The company is committed to a policy of training for employees
as a means of assuring, to each one who desires, an opportunity for fair
advancement to greater responsibilities. The administration of training
is coordinated with other personnel functions, such as selection of new
employees, transfers and promotions. Thus each employee not only has
the feeling of security in his position and his earnings but also knows
that the company is ready to help fit him for advancement to any posi-
tion within his capacity.

DISCUSSION

R. A. CoNKLiNG,*St. Louis, Mo. After three months' service with
our company, on the recommendation of the head of the department,
any employee can join the provident fund; then a fixed percentage of

* Head Geologist, Roxana Petroleum Corpn.

240 INDUSTRIAL REPRESENTATION IN THE STANDARD OIL CO. (N. J.)

his salary is retained and deposited with the parent company, with a
record of the fund. The maximum is 10 per cent, and the minimum is
5 per cent. The company sets aside an equal amount, which is invested
at about 5 per cent. If the subsidiary has been successful during the
year, the company declares a bonus which is deposited in this fund.
For the last three years the bonus was 15 per cent., this year it was 20 per
cent. That makes 40 per cent, of our salaries going into a fund into
which the employee only pays 10 per cent. This money can only be
drawn out after three years, if the employee leaves the company. If he
leaves the company before that time, he gets only his 10 per cent.

W. E. PRATT,* Houston, Tex. A point worthy of note is that this
company has undertaken to insure its men against sickness, to pay
reasonable insurance policies in case of death, and to retire the men
after various periods of service on livable wages. A few years ago,
although we heard a great deal about sick benefits and annuities, most
of the plans called upon the employees to contribute something from
their salaries, but at the present time, as exemplified by the policy of
this corporation, general opinion seems to hold it to be fairer practice,
as well, perhaps, as better business, to supply these benefits without
placing any share of the burden involved on the employee.

* Chief Geologist, Humble Oil & Refin. Co.

PETROLIFEROUS ROCKS IN SERRA DA BALIZA 241

Petroliferous Rocks in Serra da Baliza

BY EUZEBIO P. DE OLIVEIBA,* Rio DE JANERIO, BRAZIL

(Wilkes-Barre Meeting, September, 1921)

ONE of a recent batch of samples from the Serra da Baliza, in the
state of Parand, Brazil, contained asphalt and a dark heavy oil; and
workmen on the railway from Porto Uniao to Uruguay discovered asphalt
coming from eruptives that outcrop along the Rio de Peixe. The occur-
rence of asphalt in the triassic eruptives of southern Brazil, however,
has been known a long time, according to Dr. Gonzaga de Campos.

It is generally believed that the Botucatii sandstone is always a
hard vitrified rock, from the metamorphic action of the overflowing
eruptive contacts. In this region, however, the contact met amor phism
is almost nil; the sandstone is slightly hardened in a narrow zone about
20 to 30 cm. wide. In many places, the sandstone is so friable as to be
easily reduced to sand, which is used in mortar for building in Guara-
puava and Palmas. South and west from Porto Uniao, this bench of
sandstone is about 50 m. thick, and is capped by a heavy bed of basic
eruptives, many of which are amygdaloids.

NATURE OP ROCKS

Dr. Geo. P. Merrill, after studying the triassic eruptives collected by
the Coal Commission, reached the conclusion that "All these rocks are
of typical basalt-diabases, not in any essential different other than in
structure. An interesting mineralogical phase is its paucity in olivine,
which in many cases is completely lacking."

Professor Hussak, who carefully studied these rocks and their acces-
sory minerals, decided that in the dikes they are granular (diabase) and
that in the lava sheets, porphyritic (augite-porphyrite or melaphyre),
and that the latter pass evidently to normal diabases and are always
typical of effusive rocks. The examination of many slides from dikes
and sheets leads us to adopt the opinion of Professor Hussak; the rocks of
the dikes are of ophitic structure, while that of the sheets show a great
variety of structure and may vary from almost granular to basaltic.
The great paucity in olivine had been noted by Hussak, who classes
as melaphyres, the porphyritic triassic rocks in Brazil which contain
olivine.

* Geologist, Servigo Geologico e Mineralogico do Brazil.

VOL. LXV. 16.

242 PETROLIFEROUS ROCKS IN SERRA DA BALIZA

Between Porto Uniao and the Serra da Baliza, all the rocks,
apparently, are in sheets, i.e., they are all porphyritic, containing plagio-
clase, augite, iron, etc. in a variable proportion as well as the many
decomposition products. The predominant rock is black, or greenish
black, and so fine grained that even with a lens, none of the essential
constituents can be made out; it contains, however, cavities or amygdules,
empty or full of various accessory minerals, products of its decomposition.
Another rock type is chocolate colored, of a cavernous structure, con-
taining many geodes full of accessory minerals. This rock is intercalated
in a black porphyry, in a cut in the Serra da Baliza. In a cut made below
the humus and surface-earth, rounded blocks of decomposed eruptives
and blocks of metamorphosed sandstone were found, and, below this, the
more or less decomposed eruptive porphyry, in situ.

The Serra da Baliza (1040 m.) is a ridge resulting from erosion and lies
between the Rios Jangada and Iratim and the creeks Antas and Janga-
dinha. From a geological point of view, it is constituted essentially
of the two types of eruptives noted, with the metamorphosed sandstone
alongside.

All the samples of sandstone have, when freshly broken, a distinct
petroleum odor and many of them show small cavities from which exude
a heavy dark oil. Different samples of the compact black eruptive
contained asphalt in the crevices; while the chocolate-colored rock
showed not only asphalt, but a heavy oil that came out with effervescence
when heat was applied. In a piece of quartz, almost hyaline, a cavity
full of asphalt was found.

Having made excavations in all the hollows and ravines from the top
of the Serra to the foot we concluded that the sandstone does not form a
continuous bed. Probably a bed was broken into large blocks which
were carried to different levels in the molten mass during the eruptions
of the porphyrites. After an examination of a part of these rocks, Dr.
Gonzaga de Campos decided that the occurrence of petroleum is in the
contact zone of both the sedimentary rocks and the eruptives where
these are completely modified by endomorphism.

INDICATIONS OF PETROLEUM MOST IMPORTANT IN BRAZIL

These indications of petroleum in the Serra da Baliza are the most
important known in Brazil. Until now, the greater part of the known
occurrences consisted of impregnations in clayey and calcareous beds
of the Iraty shales and limestones or of asphalt, or its varieties, at different
points in the states of Sao Paulo, Parana", and Santa Catharina. Some
rocks above the Iraty horizon also have a distinct petroleum odor when
freshly broken. One such occurrence was found in Sao Paulo, by Dr.
Gonzaga de Campos. But none of these rocks show petroleum immedi-

EUZEBIO P. DE OLIVEIRA 243

ately, when freshly broken, as do those of the Serra da Baliza. Owing
to the nature of the rocks of the region, it does not seem wise to make
borings for petroleum, however, until more minute studies have been
made.

All the petroleum indications are found in the Iraty beds or in beds
above these. As far as known, there are no indications of oil in the
underlying Permian rocks nor in the Devonian beds, except a slight
impregnation at the top of the fossiliferous shales of Ponta Grossa.

It is true that the Bofete well log, registered in Doctor White's report,
mentions an oil horizon below this level; but it is quite possible that the
heavy oil given as coming from this horizon really came from the Iraty,
the rocks of which show oil only after the lapse of some time after breaking
or boring sometimes this occurs only after the application of heat.

Near the Colonia do Rio Claro, the existence of albertite penetrating
the Estrada Nova and Rio Rasto beds has been known some years.
This occurs near an eruptive contact. Albertite seems to be generally a
good indication of petroleum, as shown by Doctor White in the same
report: "That this was the origin of grahamite, albertite, uintahite or
gilsonite is certain, since recent drilling near the Ritchie mine in West
Virginia has revealed a productive oil sand (salt sand) at 1500 ft. below
the valley, and what is most significant is the fact that only a little oil is
found in the underlying sand until the wells are located from 500 to 800 ft.
distant from the fissure, thus showing that the rock has been drained in
the immediate vicinity of the latter." In the same report, he says:
"Record of a well drilled within 300 ft. of the Ritchie mine (fissure
holding grahamite), on the Macfarlan run. In this well only a small
quantity of oil was found. This sand was good but the well acted as
though the sand had been drained. Wells drilled farther from the
fissure, however, secured good producing sand as shown by the following
records. . . "

Thus drilling for oil in a region where asphalt occurs, as at Colonia
de Rio Claro, is promising but should be located some distance from
such veins of albertite, in order to avoid boring through rocks from
which the petroleum has been drained.

In Sao Paulo, also, other borings in the Bofete region would be
interesting. Though Horace E. Williams, who knows the region well,
is of the opinion 1 that the bituminous sandstones of the Bofete region
represents a fossil pool, eroded and oxidized, and that the existing strata
above the Iraty in that immediate region are, perhaps, unfavorable for
such accumulations. Whether or not this is true can only be determined
by considerable drilling. Corroborating this point of view, in part, we
find in the Diario Official the following considerations by Doctor White,
written while he was on the ground: "When I learned that the boring

1 Oil Shales and Petroleum Prospects in Brazil. See page 75.

244 PETROLIFEROUS ROCKS IN SERRA DA BALIZA

near Rio Bonito, in Sao Paulo, had found some genuine petroleum, I
was not surprised; but, as the boring had been made near a fissure in the
rocks, which permitted a great quantity of the petroleum to escape
toward the surface and saturate the sandstone with its residual products
(asphalt etc.) no oil might reasonably be expected to be found in com-
mercial quantities in this boring. The drilling should be made some
distance from this break in the rocks where the flow of eruptives has
not emptied the deposits of the underlying rocks."

ANALYSIS OF OIL-FIELD WATER PROBLEMS 245

Analysis of Oil-field Water Problems*

BY A. W. AMBROSE,! BARTLESVILLE, OKLA.
(St. Louis Meeting, September, 1920)

THE underground losses of oil exceed by hundreds of thousands of
barrels all the oil that has been lost in storage, transportation, or refining.
The quantity lost is, of course, indeterminate; but when it is considered
that the contents of an entire oil field have been excluded from recovery
by invading waters, some idea of the amount wasted may be gained.
Similarly, enormous quantities of gas have been lost underground.
Conservation of the oil, therefore, should start before it is brought to the
surface rather than after it is placed in storage tanks.

Water is one of the most important causes for underground losses and
the operator should give as serious consideration to an underground flood
of water as he would to a destructive surface flood. The best insurance,
of course, is to have the wells drilled in such a manner that water has no
access to the productive oil and gas horizons, and on abandonment the
wells should be properly plugged.

The encroachment of edge water and the occurrence of waterin;the base
of an oil sand present a very serious problem to an oil company sooner
or later these waters are bound to cause considerable damage, if they do
not entirely destroy the possibilities of further production. Too often,
however, a field has been considered to be in a hopeless condition, whereas
wells in as bad a condition in other areas have been repaired and the life
of the field appreciably lengthened. The corrections are very often
suggested by technical study. Very successful results have been accom-
plished by detailed underground work in the California oil fields, in
Gushing, Oklahoma, and in other areas.

The purpose of this paper is to outline briefly 1 general methods of
analyzing oil-field water problems in a producing or in a producing and
developing oil field, with a view to suggesting repair work on offending
wells. Reference is continually made to producing oil wells; the same
general method of procedure, however, should be adopted in a gas field.

* Published by permission of the Director of the U. S. Bureau of Mines.

t Superintendent, Petroleum Experiment Station, U. S. Bureau of Mines.

1 A bulletin, "Underground Conditions in Oil Fields," prepared by the writer,
will be published shortly by the U. S. Bureau of Mines, which goes into much more
detail than this outline.

246

ANALYSIS OF OIL-FIELD WATER PROBLEMS

OBJECTIONS TO WATER IN PRODUCING WELLS

The prime necessity of mastering the underground-water problem is
to prevent water from entrapping the major portion of the oil still under-
ground. But if this point were entirely lost sight of, there are sufficient
reasons for studying the water problems, provided the study is followed
by corrective measures.

Water is objectionable because its presence in an appreciable amount
means: (1) The ultimate loss of thousands of barrels of oil which may

7000

6000

1911 g 1912 g 1913 g 1914 g 1915

FIG. 1. EFFECT OF WATER ON OIL PRODUCTION OF A WELL.

be trapped underground; (2) the loss of casing-head gas; (3) the in-
creased lifting costs, as wells producing water cost more to pump and
the life of the tubing, pump, and sucker rods is shorter, also the
additional cost for replacement of corroded pipe lines and fittings; (4)
the possibility of water flooding the sands and driving the oil to neigh-
boring property; (5) the forming of emulsion, which necessitates expen-
sive dehydrating plants to separate the oil and water.

Fig. 1 shows the effect of water on oil production in a well. Water
appeared in this well in January, 1912. The oil production held up
during 1912, but from December, 1912, to May, 1913, it declined from
4800 to 500 bbl. per month. Water constantly increased during 1912,
and seriously interfered with the oil production during the first part
of 1913.

DIFFERENT WATERS IN A WELL

In an area drilled with a hole full of mud or fluid, the operator should
consider the contents of a sand as an unknown quantity, unless the

A. W. AMBEOSE

247

sand has been tested in a neighboring well by bailing or pumping. In
an area where the hole is filled with water while drilling, the hydro-
static head of fluid in the hole is usually greater than that of the water
or oil in the sand, hence oil or water will not come from the sand into the
drilling well. Fig. 2 is a hypothetical sketch showing several possible
waters in a producing oil field.

Those waters A and AI occurring in the sand above the producing
oil horizon are generally known as top, or upper, waters. Top water may
have access to the hole by: The shut-off being too high; the water leaking
around the shoe of the water string; poor coupling connections, due to

EJgeD 1

-Bottom

FIG. 2. HYPOTHETICAL SKETCH SHOWING DIFPEEENT WATER SANDS

cross-threading or the pipe not being screwed tight; collapsed casing;
a split in the casing; pipe worn through by drilling-line wear; or corrosion
of the casing due to strong corrosive waters in the sands.

Bottom waters E are those occurring in sand below the producing
oil horizons. To avoid bottom water, it is necessary to learn the exact
distance between the top of the water sand and the base of the oil zone,
so that the operator can avoid drilling too deep.

Where there are several producing oil or gas horizons, the water C
occurring between the producing sands is generally referred to as inter-
mediate water. 2

Edge water D occurs in the down-slope portion of an oil or gas stratum.
Edge water may be middle water in one well 8 and bottom water in a
well in another part of the field. It usually encroaches as production is

2 If there are only two producing sands, the term middle water is often applied
to the water occurring in a sand between them.

248 ANALYSIS OF OIL-FIELD WATER PROBLEMS

drawn from the wells up slope. The sand is termed an oil producer up
slope, but wells drilled into the same sand down slope will produce water.
Water may occur in the base of an oil sand, although before drawing
such conclusions it is advisable to consider carefully whether or not there
is a small formational break of an impervious bed between the oil and
water. Water, also, may occur in a lenticular body of sand and should
be treated as top, bottom, or intermediate water, according to its location
with respect to the productive sands.

DATA FOR ANALYZING OIL-FIELD WATER PROBLEMS

The following outline is suggested for the preparation and use of data
in the study of water problems and corrective work in a producing field
where drilling is still taking place and where little or no data have been
compiled.

1. Prepare forms for recording important information.

2. Assemble all drilling and redrilling records, daily well reports,
production records of oil and water, tubing depths, fluid levels, and other
data, for the purpose of compiling a complete log for each individual well.

3. Obtain the elevation and location of all wells and prepare field
maps.

4. Present underground conditions graphically by means of cross-
sections, underground structure contour maps, convergence maps, peg
models, stereograms, and miscellaneous graphic plots.

5. Study data on drilling and behavior of neighboring wells.

6. Collect and compile individual well records showing monthly
production of oil and water.

7. Review the histories of abandoned wells.

8. Carry on certain field work, such as collecting samples of forma-
tion, water, and oil from drilling wells.

9. Conduct field tests for determining the contents of different sands,
also test out "wet" wells for top, bottom, intermediate, and edge water
and water in the base of an oil sand.

10. Study the chemical properties of the waters in different sands.

11. Investigate the possibilities of using dyes or other detectors to
determine the source of the water in wells.

12. Study the indications of a field going to water.

13. Consider the source of water in individual wells or groups of wells.

14. Correct or repair wells making water.

Keeping of Records

Records form the basis for the successful operation of any property
and may be considered the yardstick by which the past and present

A. W. AMBROSE 249

conditions and future possibilities may be measured. Where a company
has no complete system of records, immediate attention should be given
the preparation of forms upon which to record important data and to the
collection of information for these forms. The forms used should be
those necessary to keep the data brought out in the following pages.

Well Logs

A well log should contain, in addition to the formations, location,
and elevation of the well, etc., a history giving complete data of the tests
and all work done on the well that will in any way serve to show the
contents of any of the sands or the condition of the casing, etc. This
history should be arranged in a chronological form in which each piece
of work is set out by itself.

Field Maps and Cross-sections

Field maps should be prepared, showing the elevation and location
of wells, on such a scale that the wells can be measured or scaled off as
accurately as the results of the survey.

Pins, with colored glass heads or with numbers on the head, may be
stuck into certain well locations to serve as legends to designate the
status of different wells. A certain color or number indicates the condi-
tion of the well, as drilling, redrilling, abandoned, etc.

In order that cross-sections may be of the greatest use, they should
be clear and simple and should emphasize the important features and
omit the unimportant. The occurrence of oil, gas, and water should be
emphasized and the casing depths should be noted. All unnecessary
figures, as depths of formations, 3 should be omitted, as these tend to
obscure the more important data.

Considerable care should be exercised in the adoption of symbols to
be used in cross-sections, as symbols avoid much lettering and furnish
the basis for easy correlation of the different logs. The symbols selected
should be in contrast with each other, easy to recognize and easy to
plot. Once a satisfactory set is adopted, the same symbols should be
used throughout the work.

The lines of cross-section selected should be such as will depict the
underground structure. Every well on the property should be included
in some cross-section, as one well may furnish a key to the situation.
In case an isolated well is located off the line of a cross-section, consider-
able care should be exercised to see that it is projected to the line of section
in a proper manner.

3 It is often advisable to record the depths of the more important formations, as
top and bottom of oil sands, markers, etc., but the practice of arbitrarily recording
the depths of formations should be discouraged.

250 ANALYSIS OF OIL-FIELD WATER PROBLEMS

A satisfactory scale for plotting cross-sections has proved to be 100
ft. to the inch; this allows sufficient detail to show a 2- or 3-ft. change in
the formation, which is about as close as is ordinarily detected by the
drill. It is only in exceptional cases that there is justification for a
different horizontal and vertical scale, because where the two scales are
different the actual conditions are not properly shown.

Correlation is based on an identification of one or more identical
strata in the logs of many wells. The term " marker" or "key bed"
has been applied to formations that are constant in thickness and occur-
rence over large areas and can be recognized in most of the wells. An
ideal marker is a .formation that carries from well to well, is of uniform
thickness, and can be readily recognized by its color, hardness, or tough-
ness. From the cross-sections, the engineers should try to trace the
marker from one well to another. In regions where there is no marked
variation in the thickness of the formation, the producing sands are
usually a certain distance below the marker. This interval will serve as
a guide in new wells to indicate at what depth the water string should be
landed and the producing horizons will be encountered. Similarly,
bottom water and other features should be noted in relation to this marker
Faults and unconformities throw the beds out of their logical place and
cause mistaken predictions. Formations may thicken or thin, causing
irregularities in the occurrence of different beds.

Where few wells have been drilled, the surface structure may offer
helpful suggestions in correlating the underground beds, as frequently
the general surface dip will indicate the attitude of the beds underground.
Unconformities and other irregularities, however, may cause underground
and surface formations to dip at different angles, but until this has been
established very often the engineer has no other guide at the start.

Underground Structure Contour Map

The underground structure contour map is useful for showing the
attitude of beds in regions of low folds and faults of small throw. The
structure is shown by means of contour lines, which are used to connect
points of equal elevation on the surface, bottom, or other definite horizon
of a key bed or marker. A structure contour map is made up, there-
fore, of a series of contour lines used to show the configuration of such a
bed. A contour interval is the vertical distance between the different
points of elevation as represented by contour lines. The accuracy of a
contour map depends largely on the number and distributions of eleva-
tions over a given area, also on the accuracy of the well logs, their loca-
tion, and elevation. The universal recognition of a marker or key bed
in an area is also a factor. The main function of the structure contour
map is to show broad structural relationships over a large area in a way

A. W. AMBROSE 251

that usually is not given by the most careful study of geological cross-
sections; it is also used in selecting well locations, in the prediction of
casing depths, well depths, etc.

Convergence Maps and Peg Models

Where the surface and underground beds are not parallel, as in some
fields, a convergence map is necessary to take account of the convergence
or divergence of different beds.

Peg models are used extensively in the California oil fields, also in
the Gulf Coast, for showing structural conditions underground. These
models are used for correlation, for the determination of proper water
shut-off points, location of water, gas and oil sands, and for bringing
out any marked irregularities of well depths, water shut-off s, etc.

Stereograms and Miscellaneous Graphic Plots

Stereograms are used to show graphically, and in three dimensions,
the broad general relationships underground. They have been used
very little to determine casing depths, water shut-off s, etc.

Miscellaneous graphic plots can be used to emphasize certain fea-
tures. For example, if considerable material has been left in the hole,
its location in relation to the producing sands may be shown by an
individual graphic plot, which brings out in consecutive order the work
done on the well at different times. The history may be shown on the
same sheet; then, by a combination of the graphic drawing and the written
history, the engineer may more easily realize the tests made and the
work done on the well.

After the marker has been definitely established in a group of wells
in a district, a set of graphic logs may be plotted to a common strati-
graphic datum. The marker of different wells is plotted on a horizontal
line and then the correlation should be along the horizontal, consequently
any irregularities of well depths, water shut-off s, tops of plugs, etc. are
readily noted.

Study of Neighboring Wells

Neighboring wells should be carefully studied, for they may furnish
information that will help to solve the problem. Cross-sections, par-
ticularly of adjoining line wells, should be made, and the casing depths
and histories of these wells carefully studied in order to obtain the
same information as is gathered on the company wells. There should
be a complete exchange of well data between neighboring companies,
particularly line wells. It has been proved many times that the exchange
of information is beneficial to both sides.

252 ANALYSIS OF OIL-FIELD WATER PROBLEMS

Monthly Individual Well Production Records

The production records of wells should be compiled in convenient
form and should show the production of oil and water for each month
during the life of the well. If there are no records, information should
be collected from the foremen and pumpers. Information so recorded,
however, should have a note telling the source of the information.

Abandoned Wells

In preparing data on different wells, special attention should be given
to the histories of abandoned wells, because these may be allowing water
to enter the producing sands. Where records of such wells are not avail-
able, it is often necessary to collect information from drillers, pumpers,
etc. Every abandoned well should be properly plugged.

Collection of Samples of Formation, Water, and Oil

Samples of formation from different horizons should be collected
from the drilling wells. These samples should be examined, marked,
and saved for future reference. Glass bottles may be used as containers;
they should be labeled to show the well number, depth, name of forma-
tion, and date collected. Samples of water representative of that in a
sand should be collected, even though there may be no need for a chemical
analysis at the time. Samples of showings of oil from any unexpected
horizon should be collected for possible analysis or need later.

Field Tests

A series of field tests of wells making water and of drilling wells should
be carried on simultaneously with the study of the data. The water
strings of oil wells making water may be tested, bottom of wells may be
plugged where bottom water is suspected, and the sands of a drilling
well should be tested. The same sand need not be tested in several
wells as one good test on a horizon in a certain area will often suffice .
The necessity for knowing the results of former tests emphasizes the
value of good records.

The location of oil sands and water sands can be determined most
satisfactorily in a drilling well because it is possible to have only one sand
exposed. The number of sands that can be tested in a drilling well are
limited only by the practicability and expense of the operation. Once
the sand is cased off, it is usually difficult to make a test of it. After a
water string has been landed, a very careful test should be made by drill-
ing a pocket below the casing shoe, bailing out water and allowing the

A. W. AMBROSE 253

hole to stand at least 6 hr., and preferably 12 hr., to see if any water
enters.

In testing the water string of a producing well, first test to see if there
is a leak in the pipe. If the casing does not leak, a bridge may be set a
few feet below the casing and a test made to see if the water is coming
around the casing shoe.

If a well is suspected of making bottom water, the bottom of the well
can be plugged in successive stages, with cement, until some definite
information is gained regarding the source of the water. Packers and
lead plugs have also been used. In plugging up the bottom of the well
to test for bottom water, it may be necessary to shoot the hole if there is
any old side-tracked casing which may serve as a conductor for the water
to work up into the well.

A bridge may be used to test out where desired. If a sand midway
between the water shut-off point and the bottom of the well is suspected
of making water, a bridge can be set in the sand suspected of carrying
water, cement dumped in to fill the hole several feet above the sand and,
after the cement has hardened, a bailing or pumping test made to deter-
mine whether or not the bridge has shut off the water. Very often a
bridge saves a great deal of needless plugging. Often intermediate water
can be located by deepening and testing successively lower sands in a
drilling well.

Testing for water in the base of an oil sand is similar to plugging and
testing for bottom waters, although much more care must be exercised.
It is important to plug the wells with cement in successive stages in order
to avoid shutting off the oil production. If, after plugging, the amount
of water is retarded only temporarily, it is evident there is water in the
base of an oil sand.

The field tests for edge water or water in a lenticular sand are neces-
sarily guided by the suspected location of the water; that is, whether the
water occurs in the top, bottom, or intermediate sands.

Water Analyses

The chemical analyses of oil-field waters can be used in solving oil-
field water problems. They are particularly useful in distinguishing
waters in different sands, and hence in determining the source of water
in a "wet" well. Perhaps the most practical use of chemical analyses
has been in the oil fields of the Gulf Coast and of California, where their
use has saved costly work that otherwise would have been necessary to
determine the source of the water in some of the wells.

The waters of each field are chemically different from those of another,
and the engineer will find that the distinguishing features of different
waters will probably vary in each field. He will undoubtedly find, how-

254 ANALYSIS OF OIL-FIELD WATER PROBLEMS

ever, some particular feature, as high chloride content, total solids, or
primary salinity, that will serve to identify one water from another.
It may be found that the properties, such as primary salinity, primary
alkalinity, etc., are not the determining characteristics of a water in
a field. In one field, the writer found that the top waters, in general,
were high in sulfates. The sulfate content decreased as the sand
approached the oil zone; and as the chlorides were negligible in the
top waters, there was a decreasing primary salinity percentage with
depth. The very bottom waters, however, had a high chloride content;
hence the bottom and the top waters would have high salinity, because
primary salinity is determined by adding the sulfate (SO^ and chloride
(Cl) percentages together and multiplying the resulting figure by 2.
The operator might be confused if he relied only on primary salinity to
determine the characteristics of the water.

In this work, the writer found it necessary to consider the chloride
content in wells before giving too much value to primary salinity percent-
age. The most satisfactory results were obtained by using the percent-
age of reacting value for comparison rather than the figures of salinity
and alkalinity. Again, it may be found that other factors will readily
distinguish the waters. For example, the bottom water of the Augusta
field, Kansas, shows total solids averaging about 36,000 parts per million,
while the upper waters average nearly four or five times as much.

Collection of Samples of Water for Analysis. A sample of water for
analysis is of no value unless it is representative of the water found in the
sand. The samples to be analyzed should not be mixed with drilling
water and a sample is of little value where several water sands are exposed
in the hole. When starting the work, the engineer should collect samples
of unmixed waters from each sand, if possible, so that he may know the
properties of the waters in definite water sands.

Where a producing well has made water for some time a true sample
may be obtained from the flow tank or sump, as other water has been
flushed out. If the well has just started to make water, and other water
has been in the tanks, it is best to take a sample from the lead line.

Application of Water Analyses. After a sample is collected and a
chemical analysis made, the engineer should interpret the analysis
according to Doctor Palmer's method. When there are several analyses,
a tabulation should be made of the properties of the waters in known
sands and of the distances of these sands from the marker. Then, when
a well starts to make water, its source can be determined by comparison
of the chemical properties of the water with those in the tabulation to
see if it is the same water as any of those recorded in the tabulation .

To show the possibilities of using water analyses, the writer will cite
one or two examples, taken from a report of the waters in the East Side
Field, Coalinga, Calif., by the writer in September, 1916, to Mr. B. H.

A. W. AMBROSE

255

van der Linden, field manager of the Shell Company of California. It
was based upon forty samples of water taken from sands of different
wells, the samples being collected from as many different sands as were
accessible. By studying the analyses in connection with the graphic
sections and well histories, it was possible to locate very definitely most
of the water sands associated with production. The results of this work
show how water sands may be definitely located; a prime necessity to
avoid drilling difficulties and future water troubles. Table 1 demon-
strates how it was possible to distinguish between the different waters
by reference to the sulfate (S0 4 ) and carbonate (CO 8 ) columns.

TABLE 1. Characteristics of Water Sands, Arranged in Stratigraphic

Sequence

Well

Source of
Water, in
Feet below
Marker

Na,
Per
Cent.

Ca,

Per

Cent.

Mg,
Per
Cent.

S04

Per
Cent.

Cl,
Per
Cent.

C03,

Per
Cent.

3,
Per
Cent.

Record 5

Above

Shell 31/34, sample No. 1. .
Shell 31/34, sample No. 2. .
Shell 31/34, sample No. 3. .
Shell 10/2

355-365
416-418
420-438
705-724

48
46

49
48

2
2
1

28
8
1

10
6

12
24
29
31

The water from Record 5, which is above the tar sand and producing
sands, has 39 per cent, sulfates and 9 per cent, carbonates. The sulfates
decrease in the successive lower water sands to Shell 31/34 No. 3 while
the carbonates increase. This particular sand in Shell 31/34 No. 3
lies just above the producing sands but below the tar sands of that well.
The sand of Shell 10/2 lies below the producing oil zones, the top of which
is 267 ft. (81 m.) lower, stratigraphically, than the bottom of the water
sand in Shell 31/34 No. 3. This bottom water is low in sulfates and high
in carbonates, as would be expected in a bottom water in this field,
but there is a chloride content of 17 per cent.

Another example of the practical application of water analyses to
producing wells is shown in Fig. 3. This well was drilled to 2677 ft.
(816 m.). All sands were perforated and the well put to pumping. The
well produced for seven days, yielding an average of 83 bbl. of oil
and 104 bbl. of water per day. It was expected to produce oil and
no water, as the other wells in this area were producing from the same
horizons and making no water. The water would have been much
more with a larger pump, but the2j^-in. (6.4.-cm.) pump would not han-
dle over 200 bbl. of fluid per day. If the water had not been shut off
it would have worked back into the oil sands and probably would have
done great damage.

A chemical analysis of the water showed it to be a decided bottom

256

ANALYSIS OF OIL-FIELD WATER PROBLEMS

water as the sulfate content was 0.1 per cent., the chloride content
24.4 per cent., and the carbonate content 25.5 per cent. The bottom
waters in this area were high in carbonates and chlorides and low in
sulfates. Accordingly, the very bottom sand was plugged off by ripping
the casing and filling the hole with cement up to the base of the next
sand 2620 ft. (798 m.). The cement was allowed to set eight days
and the well again put to producing. The well then made 80 bbl. of oil
per day and 1 bbl. of water.

0.8.

O. S.

O.S.-Sea Shells

BE! ORE PLUGGING

Shale -Sea Shells
Coarse
Fine Hard
Sea Shells

Sdy.

AFTEE PLUGGING
Total Fluid

7 Days

Jiin Eipptd and plugged
to 2620ft with cement
WATER ANALYSES

SO 4 ____ 1
CL---24.4
C0 3 ._26,5

FIG. 3. PRODUCTION OP OIL WELL BEFORE AND AFTER PLUGGING OFF BOTTOM
WATER; SOURCE OF WATER WAS DETERMINED BY CHEMICAL ANALYSIS.

Use of Detectors for Tracing Movement of Underground Waters

Some idea of the rate of flow of water from one well to another may
be gained by the use of dyes or other flow detectors. Water may come
into a well from various sources and then get into an oil sand from which
other wells are producing, thereby causing considerable damage. In an
effort to trace this water from one well to another, severa 1 means have
been used and others suggested. Certain .flow detectors have been used
with a fair degree of success in some oil fields. If the detector placed
in one well appears in another well, it shows the direction and rate of
travel of the water; but where the detector does not appear nothing is
established. The best organic dyes are not infallible, primarily because
their introduction into the oil sand through any well is not certain, rather
than because the dye may be destroyed underground. It is of the
greatest importance that any dye or detector be properly introduced

A. W. AMBROSE 257

into the water and mechanical means for insuring this can probably be
developed.

There are two general uses of dyes or other flow indicators in deter-
mining the movement of oil-field waters: To determine whether or not
water is migrating from one well to another; and to determine whether
or not the water is entering the well through a leak in the casing or around
the shoe of the water string.

In studying water migration from well to well, the dye is placed near
the bottom of the well that seems to be flooding the other well or wells,
generally in solution form, by means of a proper container in order to
prevent dilution of the dye by its coming in contact with the long column
of fluid in the hole. Often production is suspended at this well so that
the dye will not be pumped out. Neighboring wells should be pumped
vigorously and close watch made of the water for any evidence of
the dye.

Dyes and detectors have also been used in an endeavor to find out
whether or not the water string is leaking. In this case the dye, or other
material, is placed on the outside of the water string and observations
made of the fluid bailed or pumped from the wells to see whether or not
the dye has worked its way into the well. Its appearance in the water
in the well shows the existence of a leak in the water string; but its non-
appearance does not prove the effectiveness of the shut-off, for if the
formation has caved in against the outside of the pipe a few hundred
feet below the surface, the dye may be held there.

Methods that have been used and suggested for determining the
movement of underground waters are : Dyes and other materials recog-
nized by their color; chlorides, nitrates, or other salts recognized by chem-
ical analyses; lithium salts, which can be detected by the spectroscope;
Slichter electrical method.

Value of Dyes. It is customary for the operator to refer to fluorescein,
eosine, and other organic dyes as " aniline dyes" although some of them
are derived from substances other than aniline. Fluorescein, eosine,
methylene blue, magenta or fuchsine, and Congo red have been suggested
as dyes which could be used.

Fluorescein is perhaps the best organic dye that can be used, primarily
because it is noticeable when present in very minute quantities and
because it is not adsorbed by clays. Fluorescein will penetrate an acid
solution further than eosine and will give a color reaction that eosine
may fail to do. It will also stand sulfureted hydrogen and sulfurous
acid. It can be detected with the naked eye when present in the pro-
portion of one part in forty million; and by the aid of the fluoroscope when
present in the proportion of from one part in five hundred million to one
part in two billion. Congo red is too sparingly soluble. Methylene
blue and magenta are basic colors and all basic colors are adsorbed by

VOL. LXV. 17.

258 ANALYSIS OF OIL-FIELD WATER PROBLEMS

clays and are, therefore, unreliable. Fluorescein and eosine are not
adsorbed by clays.

Fluorescein and other organic dyes have been used with success in
certain cases and show that water travels from one well to another, but
so far as the writer knows, the dye has failed, in the majority of cases, to
appear in adjoining wells or in a well into which it is placed when it was
inserted behind the pipe.

Certain inorganic substances, such as potassium dichromate and
Venetian red, have been suggested as flow detectors. The use of potas-
sium dichromate in oil-field waters is questionable, however, because
many oil-field waters have a yellowish tint; it is decolorized by reducing
agents, such as hydrogen sulfide; and it would require an exceedingly
large amount of the compound to color such a large volume of water.
The use of Venetian red also is limited because it would filter out quickly
when passing through a sand; furthermore, it is not detected when pres-
ent in as small quantities as is fluorescein.

Chlorides, nitrates, and lithium salts, also, have been suggested as
flow detectors but, for various reasons, their use is limited.

Slichter Electrical Method

Slichter has described 4 an electrical method of measuring the velocity
and direction of flow of underground water in shallow wells (about 50 ft.
in depth) . The method has been suggested as of possible use in detecting
the movement of underground waters in oil fields, but it shows no promise
of practical application in tracing the movement of underground oil-field
waters in deep wells.

INDICATIONS OF A FIELD GOING TO WATER

The flooding of the oil sands of an area by top, bottom, or intermediate
water can often be prevented by the correction of a few offending wells
when the trouble starts. The operator should, therefore, investigate
promptly any marked increase in the water content of a well.

The indications of a field going to water vary with each locality, but
the most common and positive evidence is for the oil wells to start produc-
ing water. When a group of wells located high up on the structure, for
instance on the top of a dome, show water while wells down slope do not,
some well is at fault. In such a case the cause may be due to improper
water shut-off points, leaky water strings, wells drilled into bottom water,

4 Charles S. Slichter: Description of Underflow Meter Used in Measuring the
Velocity and Direction of Underground Water. U. S. Geol . Survey Water Supply
Paper No. 110 (1905) 17-31; or Field Measurements of the Rate of Movement of
Underground Waters. U. S. Geol. Survey Water Supply Paper No. 140 (1905).

A. W. AMBROSE

or wells improperly plugged when abandoned. Top water, bottom water,
and water in a lenticular sand may show in wells scattered irregularly
throughout a field; these three waters usually lend themselves to repair
work on the wells.

Water in the base of an oil sand and edge water present a much more
serious problem, for as the oil and gas are withdrawn they will be replaced
by water. Water in the base of an oil sand often occurs in abundant
quantities; as a hole is carefully plugged up with cement, and by stages,
the water production is only temporarily retarded. When the wells
farthest down slope, located along a line parallel in general to the under-

8CCO

?iote:-UU production
increased 1940 bbl.
per month just pre-
ceding and foUovine
i(pearai.ce of water

1915

FIG. 4. INCREASE IN OIL PRODUCTION FROM OIL WELL PRIOR TO ENCROACHMENT

OF EDGE WATER.

ground contours, show an increased water content, there is suspicion of
of the encroachment of edge water.

A sudden increase in oil production has been noticed in wells just
before edge water appears. This is shown in Fig. 4. It will be noticed
that the average production per month was 1940 bbl. more following the
appearance of water in appreciable quantities in January, 1912.

SOURCE OF WATER IN INDIVIDUAL WELLS OR GROUPS OF WELLS

Determination of the source of water in a field is dependent on accu-
rate and complete records. Each well presents its own problem, but
there are certain fundamentals that may be outlined here. Prob-

260 ANALYSIS OF OIL-FIELD WATER PROBLEMS

lems should be attacked from two sides study of old data and field tests.
As the problem is studied from the records and graphic data prepared,
the suggestions of the source of water in any well should be checked and
tested by mechanical and field tests on the wells.

Production records indicate the wells that are making large amounts
of water and complete records show when and where the water first
appeared. Fluid-level records may possibly indicate what well is causing
trouble afcd, often, water analyses will show immediately the source of
the water. The history of an abandoned well may indicate that the well
was not properly plugged, hence it may permit water to flood adjoining
wells. It is advisable to consider whether a chemical dye has been used
to trace the water, and, if so, what were the results? Careful consider-
ation should be given to the field tests made on the different water strings.

With the correlated cross-sections before him, the engineer can make
a detailed study of each well and prepare a tabulation showing: (1) The
distance between the marker and the bottom of the hole; (2) the distance
between the marker and the bottom of the water string ; (3) the distance
between the marker and the top of a plug; (4) the water production before
and after the plug was put in; (5) the water production before and after
any deepening job; (6) the initial and present production in oil and water;

(7) date at which the well started to make a serious amount of water;

(8) remarks as to what any field tests showed; and (9) the source of the
water according to the analysis, etc. All of this information may be
tabulated under each well on the cross-section, as well as on a sheet of
paper, where there are many wells to investigate.

In studying histories, it may be noticed that water appeared at a
time after the pipe was pulled from an adjoining well which was improp-
erly plugged upon abandonment.

The question whether or not a well is making top water should be
considered from two phases: First, whether the water string leaks and,
second, whether the casing shoe has been landed too high. The history
will also indicate whether a well made water when it was drilled in or
whether the water started later. The history will also show what bail-
ing tests were made on the wells at the time the water string was
landed. If the original tests were satisfactory, the chances are that
water has not broken in later.

The casing may be tested by a casing tester or by setting a plug in
the casing shoe; again, a plug may be placed several feet below the casing
shoe of the water string; then a bailing test would test not only the casing
but the effectiveness of the water shut-off job as well.

In looking for top water, the engineer should first select a well at
which the water string is landed highest stratigraphically, but still
makes no water. After the proper landing point for the water shut-off
strings has been determined, this distance should be expressed with

A. W. AMBROSE 261

reference to the marker, so that by the use of sections and tabulations
it can be readily told whether or not the shut-off point is too high in
other wells.

The possibilities of bottom water should be considered. To deter-
mine if the well has been drilled too deep, as indicated by the tabulation,
showing the safe point to which wells may be drilled without encounter-
ing bottom water, the well that has been drilled deepest stratigraphically
but still makes no water should be selected. This then determines a
depth to which a well can be drilled with safety. The engineer must
bear in mind that often comparison can not be made of wells located a
great distance apart because, where there is an edge-water condition,
the sand down slope may have water while up slope it contains oil.
Plugging jobs also give information concerning bottom water. If the
well has been plugged, the engineer should review the tests made after
any plug was put in to see whether or not there is good evidence that
the plug was tight. If bottom water is suspected, and it has not been
plugged off, a test may be made with a plug, preferably cement. Bottom
water may be indicated by deepening jobs shown in the history; if a
well made no water until deepened, a marked increase in water after-
wards would indicate that this well had encountered bottom water.
Bottom waters usually have distinct chemical properties.

When all information and tests indicate that it is not bottom water,
the possibility of water coming from a middle horizon should be con-
sidered. This is a difficult water to test. When middle water is pres-
ent, it is necessary to make certain first that the water is not coming
from top or bottom. If the water string is landed low enough and the
ori inal bailing tests indicate a tight job, and, furthermore, if the well is
not drilled deep enough for bottom water, evidently the water is coming
from an intermediate source. Evidence is also gained by considering
histories of adjacent wells, to note whether these wells have a similar
water and, if so, if the bottom of any of the holes has been plugged. If
a plug that should have held back any bottom water was once placed
in the bottom of the hole, but the well still made water, there is indica-
tion that the water is coming from higher up the hole. In looking for
the water of the middle horizon, it may be that adjoining wells were
deepened in successive stages and the histories of these wells may in-
dicate the depth below the marker at which middle water is encountered.
The middle-water sand often has definite properties distinct from those
of the top and bottom waters, which differences are brought out by water
analyses.

Edge water may be suspected when a group of wells down slope show
increased oil production. In addition, a group of wells located roughly
parallel to a structure contour may show a sudden increase in water.
It may be noticed that wells will produce oil from a certain sand in one

262 ANALYSIS OF OIL-FIELD WATER PROBLEMS

locality while down slope this same sand contains water; some place
between these wells there is an edge-water line and in time the water
will encroach on the oil wells.

There remains, of course, the possibility of the wells making water
from the base of an oil sand; a water analysis may indicate a new water
which lies in the base of the sand. These wells usually turn from oil
to water very suddenly. Where the water occurs in the base of a sand
in a flowing well with large production, there is little evidence of gas and
the well often flows very evenly. The production of water coming from
the base of an oil sand is only temporarily retarded by plugging.

A lens of water will be detected by a different kind of water, as shown
by water analyses; a study of well histories will show that only a small
number of wells in a certain locality have this water. Inasmuch as a
lens of water may occur in any part of the geologic column, it is often
referred to as top, bottom, or intermediate water, depending on its loca-
tion in reference to the oil sands.

CORRECTION OF WELLS MAKING WATER

In the various studies and field tests, the engineer should have ideas
of the sources of water in the different wells and the location of the differ-
ent oil sands. Recommendation should be made for correction of wells
that may be letting water into any producing oil well.

Top Water

In case of a leak in the casing, one remedy is to place a packer between
the tubing and the water string. Where there is a full oil string, it may
be necessary to cut the casing and leave only a liner in the hole so that
the packer may fill the annular space between the tubing and the water
string.

The water string may leak because it was not screwed together.
By screwing pipe together, it has been possible to shut off a leak in the
casing.

If the casing leaks because of a collapsed water string, it may be
swaged out; but very often it is difficult to repair such a leak. A packer
may be used or some cement forced through the hole in the casing behind
the pipe, but often another water string must be landed deeper to shut
off the water, especially in a drilling well.

A leak in the pipe may be caused by a split joint in the casing or by
corrosive waters eating through the casing or, possibly, line wear. If
the split is large, a bridge capped with a cement plug may be placed in
the pipe and cement forced through the leak. If the hole is small the
casing may be ripped and cement forced in behind the pipe.

A. W. AMBROSE 263

Where water is leaking around the shoe of the casing it may be pos-
sible to place a bridge several feet below the shoe of the water string and
then fill the top of the bridge with brick, stone, or cement. After the
cement is set, cement may be forced behind the pipe under pressure,
although usually this is not an efficient and satisfactory means. If cir-
culation is possible, cement may be pumped in behind the pipe, as de-
cribed by Tough. 5 Where circulation cannot be obtained, cement may
be forced through the tubing behind the pipe under pressure. Often-
times when the water is leaking around the pipe it may be necessary to
cement a smaller-sized string of casing a few feet deeper, provided the
oil sand is not too close; if the oil sand is too close, redrilling is often
necessary, after shooting the bottom of the casing, and then recementing
the string at the same depth. On some occasions, it has been possible
to drive the pipe several feet to make a lower formation shut-off; also
a liner has been landed with cement around the outside, so as to shut
off a water sand directly below the casing shoe.

Bottom Water

Cement is recommended for plugging the bottom of the well where
it has been established that the water is coming from bottom. Mud-laden
fluid has been used, but is not to be recommended generally; likewise, a
lead seal or packer has shut off bottom water, but the writer prefers
cement.

Intermediate Water

When intermediate water is present, the operator must exercise great
care in protecting the upper oil sands while producing from the lower
sands or vice versa. In producing oil from the lower sands only, the
upper oil sands should be protected either by the use of mud-laden fluid
behind the pipe or by pumping a liberal amount of cement behind- the
water string. The producer should make certain that a sufficient quan-
tity is pumped in so that the top of the cement is actually above the
upper oil zone; this will prevent the middle water from entering the
upper oil horizon.

Where a well is making a large amount of water from an intermediate
sand and is producing from both the upper and the lower oil zones, the
well must be plugged up from the bottom to above the middle water and
production taken from the upper sand, or else redrilled and a string of
casing landed below the intermediate water. In plugging, it is best to
use a large amount of cement to protect the lower sand; and where a
new string is landed below the intermediate water, sufficient cement or

6 F. B. Tough: Methods of Shutting Off Water in Oil and Gas Wells. U. S. Bureau
of Mines Bull. 163.

264 ANALYSIS OF OIL-FIELD WATER PROBLEMS

mud-laden fluid should be placed behind the pipe to assure proper pro-
tection of the upper oil zone.

Goodrich suggests the use of a liner with packers on the outside of the
pipe at the top and bottom to shut off an intermediate water. The
liner would be set opposite the water sand, as the packers would be
expected to confine the water to the sand. Where the water has any
appreciable head, it is very doubtful if this method, in the majority of
cases, will prove satisfactory.

Edge Water

The following are suggested methods for restraining encroaching
edge water: (1) Use of compressed air to hold back the water by forcing
air into those wells nearest the edge-water line, thus holding back the
water while allowing increased production in the wells up slope. (2)
Drilling ahead of the approaching water and plugging the well as soon
as the water becomes troublesome.

For the purpose of obtaining a maximum production, a careful study
should be made of drilling costs and production in order to arrive at an
economic cost balance that will determine the maximum number of wells
that can be drilled in order that the production may yield the largest
profit possible. In short, the encroaching edge water will entrap much
of the oil underground, so the operator should plan to get the greatest
profit per barrel of production. In the case of edge water, this study
should be made before water becomes the master.

Edge water may occur in the top, middle, or bottom oil sands. If
edge water occurs in the top sand and the water has advanced to the well,
it is-, of course, a matter of treating the upper sand as a top-water sand
and then making a shut off below it.

Where there are several producing sands and the edge water occurs
in an intermediate sand, it may be handled by plugging, with cement,
from the bottom to a point above the water sand, after which the operator
can produce from the top sand in that well. In doing this, great care
should be taken that no water is allowed permanent access to the lower
oil zones. Another way is to redrill the well and land a water string
below the edge-water sand and the well made to produce from the lower
zone. It is important in such a case that the top oil sands be properly
protected.

If edge water appears in the bottom sand of a well, it should be plugged
off by cement and production taken from the sands above.

Water in the Base of an Oil Sand or in a Lenticular Sand

The operator should be certain that the water and oil are not separated
by a small break before deciding that the water occurs in the base of an

DISCUSSION 265

oil sand. It is very difficult to place a thin cement plug of an exact
thickness by ordinary dump bailer methods, but cement should be used
and the well plugged in stages and tested. In each test the operator
should see if the cement is hard and should plug only a few feet at
a time

The McDonald method of shutting off water in an oil well has been
very successful in the Illinois field and has been described in a bulletin
of the Illinois Geological Survey. 6 A description is also given in an
article by Tough. 7 When the water and oil together occur in the same
sand, the application of the McDonald method or any other can at best
only delay its approach, for eventually water will cause much trouble
and expense.

A lens of water may occur any place in the productive zone and
should be handled as a top, bottom, or middle water, depending on its
location.

DISCUSSION

R. A. CONKLING,* St. Louis, Mo. We have found it more helpful
to observe the amount of water by the sands above the oil than to analyze
the water. A well in Texas came in at 1000 bbl. but in about a week
began to show water. After the fourth day about 30 bbl. of water were
produced. The field department thought it was bottom water and
wanted to plug immediately. It has been producing for the last three
months and has been making about the same amount of water that the
water sands were thought able to produce.

In another case we went through a couple of water sands and ran
into an oil sand about 200 ft. below.' We have been trying to get the
field department to repair that well, because we know the water will go
down when we get to the shallow oil sand. This shows that the geologist
in the field should keep close records while drilling, for such records will
help solve problems that will come up later.

E. DEGOLYER, New York, N. Y. One point in connection with the
question of bottom water that has not been considered much in American
practice is keeping down the water by checking the flow of a well. In
Mexico, especially in the southern part of the Tampico-Tuxpam region,
oil occurs in very porous limestone and probably moves with an ease and
freedom that is not equalled in any knwn field of the United States.

6 F. H. Kay: Petroleum in Illinois in 1914-1915. Illinois State Geol. Survey
Bull. 33 (1916) 87-88.

7 F. B. Tough: Methods of Shutting OS Water in Oil and Gas Wells. U. S.
Bureau of Mines Bull 163, 82-85.

* Head Geologist, Roxana Petroleum Corpn.

266 * ANALYSIS OP OIL-FIELD WATER PROBLEMS

Under the oil is the bottom water, which is practically the only water.
Conditions are more or less artesian. If an oil deposit is trapped over
water having an artesian head in an anticline, you have a condition simi-
lar to that existing in Mexico. In a certain field where the deposit of oil
was possibly only a few feet thick, the entire field was practically ruined
by trying to make 10,000-bbl. wells out of what were probably 100-bbl.
wells. One well produced 6000 bbl. of clean oil in the first few hours,
but water then broke through and in three or four minutes the product
turned through the various shades from jet black to a dirty lemon yellow
as the percentage of water increased and the well was ruined.

In one of the larger fields, when a well making 18,000 bbl. of clean oil
began to show water, its production was reduced to 16,000 bbl., which
checked the flow of water for a few months. Whenever water appeared,
the production was checked and the oil cleared. The well is now pro-
ducing 900 to 1000 bbl. of clean pipe-line oil. Over 2,500,000 bbl. of
clean oil have been obtained since water first appeared by thus nursing
the well along. We have made a set of curves showing temperature,
water and sediment, flow-line pressures, etc., that demonstrates clearly
the conditions governing occurrence of oil in Mexico.

Until the Potrero del Llano well began to show water there were only
slight variations in the temperature of the oil. When water appeared,
the temperature of the oil increased 18 to 20 F. within twenty-
four hours.

MR. REILLEY. Isn't it just as necessary to curb a well making a
large volume of gas with the oil as it would be to curb a well with less gas
making the same volume of water?

E. DEGOLYER. My whole consideration of this subject bears on
the question of raising the critical cone in the water table and of
lowering the top of that cone. I think that if there is a lot of gas with
the oil, the cone is likely to be much sharper than with the dead, heavy
oil. The worst condition resulting from water coming is when the
crest of the cone reaches the bottom of the casing in a well and thus cuts
off any remaining oil.

R. VAN A. MILLS,* Washington, D. C. The Bureau of Mines has
made a large number of experiments with oils of different viscosities
under different rates of recovery that tend to substantiate many of Mr.
DeGolyer's remarks. It is necessary to study the differences in the be-
haviors of oils of different viscosities as influenced by the rates of recovery
under various conditions. In doing this work the Bureau of Mines is
studying the relative times required to form water cones under different
conditions of flow, together with the time required for the cones to

* Petroleum Technologist, U. S. Bureau of Mines.

DISCUSSION 267

flatten out under retarded conditions of flow, as well as during periods
of rest. As a rule, water cones are accentuated by increased rates of flow,
and decreased or eliminated by reductions in the rates of flow. My
experiments indicate that under certain conditions water cones form
more readily with dead oils than with oils heavily charged with gas.
In attacking these problems it is dangerous to generalize because of the
many factors and different sets of limiting conditions involved in the
different fields.

R. A. CONKLING. Our department has an exploration geologist,
who has charge of the drilling of all wells; the total depth is always sent
out from the St. Louis office. A geologist in the field sends in samples
and works up as much data as possible. We have a lease 1 mi. long and
y mi. wide with four operators operating around, offsetting it. On the
north, the wells began making water almost as soon as they were drilled
in. Wells come in from 1000 to 3000 bbl. Until a week ago, we did not
have 0.5 per cent, water, by analysis, in all of the oil on that lease; the
adjoining leases have from 5 per cent, to 100 per cent, water; three wells
are all water.

We simply stop the wells above water level when the edge water has
just begun to come; the field department will plug back, because there
is plenty of sand and the water will soon rise to that level.

At one time 30,000 bbl. of crude oil were turned out by one operator.
He did not have any place to keep it so he had to turn it loose to take
care of the other oil. That is what we save the company.

In another case the field department struck water and wanted to
know whether to plug back. It was above our water level, and we
had two other wells going down to deep sand nearby. Knowing that
that was not the true water level, we told them to bail for a week. After
bailing four days, the water was gone, so we deepened the wells to the
proper horizon.

R. VAN A. MILLS. In considering the determination of the source of
oil-well water by chemical analysis, one must bear in mind the fact that
the water produced from an oil-bearing horizon in a new field may be
different from the water produced from that same bed a year or two later;
not because water has leaked into that bed through wells, but because
the water in that bed has undergone induced changes. Water associated
with oil and gas in the pays undergoes induced concentration through
the removal of water vapor in expanding gases, the concentration being
accompanied by changes in the relative proportions of the dissolved
constituents. The fact is emphasized that differences in the analyses of
waters collected from the same well at different times do not necessarily
indicate the infiltration of top or bottom water, especially if edge water
accompanied the oil and gas in the pay when the well was brought in.

268 ANALYSIS OP OIL-FIELD WATER PROBLEMS

Again, we must consider the relations that the viscosities of oils,
the pressures and proportions of gases accompanying the oils, and the
textures and bedding of sands bear to the differential movements between
oils and water. For instance, the differential movements between
Appalachian crude oils of low viscosity and water are comparatively
slight, whereas with oils of higher viscosities the differential movements
are so pronounced as to lead operators to think that wells or entire fields
have gone entirely to water, when in reality the wells are affected only
by water cones, a large part of the oil still remaining to be recovered.
Experiments show that an Appalachian oil of low viscosity migrates
readily under the propulsion of hydraulic currents, whereas under the
same conditions a California crude of high viscosity fails to migrate at
all. Obviously the effect of water on oil recovery depends largely on
the viscosities of the oils the more viscous the oils, the more detrimental
is the effect of water.

Oil is propelled to wells by the expansive force of gas. Under certain
conditions the oil is thus propelled to the wells ahead of water, but
as the gas is exhausted, this relationship may change so that the water
advances to the wells ahead of the oil. This is illustrated by gushers
in which we have slight, if any, shows of water until a large proportion
of the gas is exhausted.

The sizes of pores through which the fluids pass also have a decided
influence on the relations of water to the recovery of oil. Under various
conditions, the differential movements between oil and water are accentu-
ated as the sizes of the pores are diminished. Where the sizes of pores
are sufficiently diminished by induced cementation, the recovery of oil
may be greatly retarded or entirely prevented It is imperative that
we consider these fundamental principles in attacking oil-field water
problems.

OIL-FIELD BRINES 269

Oil-field Brines

BY CHESTER W. WASHBURNE, NEW YORK, N. Y.

(St. Louis Meeting, September, 1920)

RECENTLY, Messrs. Mills and Wells 1 published a thorough chemical
study of the waters associated with oil in parts of the Pennsylvania,
Ohio, and West Virginia region. Many of their conclusions are of gen-
eral application and the writer wishes to discuss some of these.

Messrs. Mills and Wells show that the composition of the deep brines
of the Appalachian fields is such as would be produced by the evaporation
of sea water and the precipitation of sodium chloride, combined with
reactions with hydrocarbons and other substances. The brines are
altered, also, by considerable mixing with meteoric water. They give
good reasons for believing that the concentration of the brines was pro-
duced by evaporation in the rock pores induced by migrating gas, much
of which probably escaped to the surface of the ground.

This hypothesis was considered by the writer in a former paper, 2
in which main stress was laid on a second hypothesis, that the excess
of chlorine in the deep brines may have been due to the entrance
of solutions rich in magnesium and calcium chloride which ascended
from a deep, possibly intratelluric, source. Messrs. Mills and Wells
present good arguments for the first hypothesis. Underground evap-
oration by ascending gases probably will be accepted as the best
available explanation of the concentration and composition of deep well
waters.

They have not considered the possibility that salt waters in deep
sands may be concentrated by the diffusion of water vapor through gas
into shale. The writer has given reasons 3 for believing that capillary
forces concentrate gas and oil in the larger openings of rock, such as the
pores of sandstones embedded in shale. The gas underground must be
nearly saturated with water vapor at all times, because it always is in
contact with the interstitial water of enclosing shales and of the sand-
stone. Experimental studies of soil moisture have shown that approxi-

1 R. Van A. Mills and Roger C. Wells: The Evaporation and Concentration of
Waters Associated with Petroleum and Natural Gas. U. S. Geol. Survey Butt. 693
(1919).

2 C. W. Washburne: Chlorides in Oil-field Waters. Trans. (1914) 48, 689, 690.

3 C. W. Washburne: The Capillary Concentration of Oil. Trans. (1914) 60, 829.

270 OIL-FIELD BRINES

mately saturated soil air deposits its moisture on concave water surfaces
of sharp curvature, such as the capillary surfaces in the pores of clay,
while it is absorbing or evaporating water from concave surfaces of
larger curvature, as in sands, where the water films are relatively broad. 4
In this way there is probably a slow migration of water vapor from sand-
stone into shale. The process is essentially a diffusion of water vapor
through gas. It is effective only to the extent that the shale contains
gas to exchange for the water it receives from the sand. Nevertheless,
this process of vapor diffusion operating through geological periods would
be a potent factor in evaporating the water in sands. It would operate
in either stagnant or moving gas, and is regarded as supplemental to
the process of evaporation by convection in moving currents of gas
postulated by Messrs. Mills and Wells. This process of diffusion of
water vapor and its condensation in shale would increase the concentra-
tion of the brines.

ORIGIN OF SALT CORES

Messrs. Mills and Wells carry their theory to its ultimate limit in
trying to explain the origin of the salt domes of the Gulf Coast and other
regions. They show that the volume of gas required to deposit salt
under a pressure of 100 atmospheres and " under reasonable conditions"
is from 145 to 1550 times the volume of salt deposited. The smaller
figure is for temperatures of 100 C. and the larger figure is for 40 C.
From the depth of the upper part of the salt cores, the temperature of
deposition probably did not exceed 40 C. unless deep-seated hot waters
were involved; hence, the volume of gas required would be about 1500
times the volume of salt.

Do they realize that the volume of most of the salt cores probably is
over one cubic mile? Some of the domes, such as Humble and South
Dayton, have proved volumes of five cubic miles or more, and possibly
of many times this amount if they extend as far downward as commonly
thought. Could the required 1500 or 7500 cu. mi. of gas be furnished
by the thick sediments underlying the region tributary to any salt core?
If this volume of gas, measured under 100 atmospheres pressure, escaped
in one geological period at the site of any salt dome, it could be only
through vertical channels which would necessarily be so free and open
that there could have been no accumulation of oil and gas at these places.
Moreover, the salt cores are at least a few thousand feet in height and
cut so many water-bearing sands that the writer doubts if any process
could concentrate the solutions to saturation. The water in these sands

4 Lord Kelvin. Referred to by Lyman J. Briggs: The Mechanics of Soil Moisture.
U. S. Dept. of Agric., Div. of Soils, Bull. 10 (1897) 12, with reference to Maxwell:
Theory of Heat, 287. Important later references not at hand.

CHESTER W. WASHBtTRNE 271

generally is only moderately saline, and commonly is under artesian
head. At least some of the sands outcrop in higher country farther
inland. Some of them furnish potable artesian water in the same gen-
eral region, but not in the oil fields, where potable water occurs only in
the shallower sands, although a few of the flows of deep waters are only
moderately saline.

The region where the sands outcrop has not been submerged since
they were deposited by fresh-water streams. The region of most of the
productive salt domes probably was temporarily covered by the sea in
Neocene time. Possibly the coastal parts of many of the oil sands are
marine; marine shells occur in the lower water-bearing sands of the
Goose Creek field. Some of the sands appear to be local and not to
extend far inland, being possibly beach sands that spread laterally along
the Tertiary sea shores. Other lenticular sands may occur. However,
there are several wide-spread sands and it is probable that their outcrop
always was higher than the region of productive salt cores. Hence, the
water in the outcropping sands always tended to flow toward the sea,
maintaining a certain degree of freshness in the sands. If this inference
is correct, it would be impossible for salt cores to grow upward across
the sands by any process of precipitation, because there must have been
sufficient artesian circulation in the sands to keep the waters dilute.
This artesian circulation would be set up as soon as fissures or other
vertical channels were opened for the ascent of the hypothetical salt
solutions. 5

The mixing of the meteoric waters from the sands with the hypothet-
ical rising salt solutions would keep the latter from reaching a state of
saturation. All theories of the chemical origin of the salt cores postulate
a period of free upward circulation at the loci of the domes. Such free-
dom to move upward would release the partly meteoric waters in the
Tertiary sands and would let them circulate more rapidly down the dip,
increasing their freshness. These waters would enter any vertical fis-
sures and would prevent the deposition of salt therein; in fact, they prob-
ably would be fresh enough to dissolve any salt previously deposited.
Hence it seems impossible that the salt cores could have been precipi-
tated from waters that rose along fissures cutting all of these water-
bearing sands. A better explanation is that presented by van der
Gracht, 6 that the salt cores are essentially intrusive masses that were

6 Vigorous natural artesian circulation of this type is taking place at the salt
dome at West Point, Tex. This dome is surrounded by a ring-shaped valley full of
fresh-water springs. The water comes from sands in the Wilcox formation. There
are also some salty springs. See E. De Golyer, JnL Geol (1919) 28, 653.

6 S. W. Assoc. Petrol. Geol. Bull 1 (1917) 85. See also G. S. Rogers: The Origin
of the Salt Domes of the Gulf Coast of Texas and Louisiana. Econ. Geol. (1918) 13,
447; DeGolyer, Trans. (1919) 61, 456; Rogers, Econ. Geol (1919) 14, 178.

272 OIL-FIELD BRINES

squeezed up in semiplastic condition from hypothetical salt beds in the
Permean or other underlying strata.

There seem to be only two dubious ways by which the fresh-water
sands could be sealed sufficiently to prevent them from flooding the
fissures. The first would be by clogging their pores with salts next to
fissures in which large quantities of warm gases were rising from below.
This method might effectively seal off the sands that contained nearly
saturated solutions, but many sands are involved, and it seems probable
that some of these that outcrop inland must have furnished strong flows
of comparatively fresh water, which would prevent their becoming
clogged by salt. The second way is as follows: Gas rising from great
depths tends to maintain some of its original pressure by expanding.
The gas rising in a fissure might be under higher pressure than the water
in any artesian sand cut by the fissure. It would seem, therefore, that
the gas would enter the water sands and drive back the water. The gas
would enter the sands to a certain extent, especially through the larger
pores where capillarity exerts less resistance to flow. The gas could not
hold the water back in the finer pores of the same sand. Thus, circula-
tions would be set up whereby water in the sand would be exchanged for
gas in the fissure, until the pressure in the sand nearly equaled that in
the fissure after which large quantities of water could enter the fissure
from the sand. This method would be no more effective than an attempt
to use gas to seal off a water sand in a deep well.

In other words, it seems impossible to postulate the precipitation of
salt from solutions ascending in fissures many thousand feet across the
broken edges of the Tertiary strata of the Gulf Coast. There are, and
always have been, too many sands in these formations that contain fresh
or moderately saline artesian waters, which would enter the fissures and
would prevent precipitation of salt.

ORIGIN OF GYPSUM IN SALT DOMES

Thick bodies of gypsum are present near the tops of some of the salt
cores of the Gulf Coast. These generally overlie the salt, having thus
the same position that is commonly occupied by gypsum in the salt
mines of Germany and other places. This suggests that the gypsum
may have ascended en masse on top of the intrusive body of salt, but it
is not a conclusive argument against other theories.

Messrs. Mills and Wells have observed the deposition of calcium
sulfate in the bottom of wells, where sulfate waters had leaked down the
casing from upper levels and had mixed with brines rich in calcium
chloride. This suggests that the tops of the salt cores of the Gulf Coast
may have been the places where descending sulfate waters mingled with
brines of the oil-field type rich in calcium chloride, which would cause
the precipitation of gypsum at that horizon. The latter explanation is

CHESTER W. WASHBURNE

273

necessary only if one adopts the theory that the salt cores were deposited
from solutions. It is a possible source of the gypsum under either theory.
E. DeGolyer, 7 referring to the chemical work of Frank K. Cameron, 8
shows that the gypsum may have been deposited against the salt mass
where the sulfate-bearing waters dissolved sodium chloride until they
became highly concentrated therewith. Cameron showed that in a
highly concentrated solution of sodium chloride gypsum is much less
soluble than in a moderately concentrated solution. This doubtless
would be an efficient method of precipitating the gypsum which had been
dissolved from surrounding strata by moderately concentrated solutions
of sodium chloride. However, a study of the following table by Cameron,
copied from DeGolyer, 9 shows that the addition of sodium chloride,
however great the amount, could not precipitate the gypsum dissolved

Solubility 10 of Calcium Sulfate in Aqueous Solutions of Sodium Chloride

a* 23

NaCl,

Grams per
Liter

CaSO,,

Grams per
Liter

Gypsum,
Grams per
Liter

NaCl,
Grama per
Liter

CaS0 4 ,
Grams per
Liter

Gypsum,
Grams per
Liter

0.99

2.37

2.99

129.50

7.50

9.42

4.95

3.02

3.82

197.20

7.25

9.17

10.40

3.54

4.48

229.70

7.03

8.88

30.19

4.97

6.31

306.40

5.68

7.19

49.17

5.94

7.51

315.55"

5.37

6.97'

75.58

6.74

8.53

a The solution in this case was in contact with both gypsum and sodium chloride
in the solid phase.

from surrounding strata by solutions containing less than about 40 gm.
per liter of sodium chloride. In other words, the original solution of
the gypsum must have been effected by solutions of sodium chloride
stronger than 40 gm. per liter. This restriction may limit the possible
source of gypsum to a small zone immediately surrounding the salt mass,
because there is reason to believe that most of the water in sands remote
from the salt cores contain less than 40 gm. per liter of common salt.
The table also indicates that anhydrite would be the mineral generally
deposited, rather than gypsum, but the former readily converts into the
latter under certain underground conditions. Both minerals occur in
the cap rocks.

7 Origin of the Cap Rock of the Gulf Coast Salt Domes. Econ. Geol (1918) 13,
618-619.

8 Various papers, U. S. Dept. of Agric., Div. of Soils, Bull. 18, 33 and 49; also
Jnl Phys. Chem. (1901) 6.

9 Loc, cit.

10 Frank K. Cameron: Solubility of Gypsum in Aqueous Solutions of Sodium
Chloride. U. S. Dept. of Agric., Div. of Soils, Butt. 18 (1901) 25-45 (Table IX).

VOL. IAV. 18.

274 OIL-FIELD BRINES

ORIGIN OF GYPSUM IN THE RED BEDS

The structure of the thick masses of gypsum found in the Red Beds
of the Western part of the United States and other regions is strongly
suggestive of a secondary origin. Some gypsum beds spread with fairly
uniform thickness over broad areas, as the main gypsum bed of the
Permean of southern Oklahoma. Beds of this type appear to have been
deposited in semi-enclosed basins, possibly near the margins of the sea.
In other cases, remote from known seas of the same age as the gypsum,
as in the Big Horn Basin of Wyoming and south of the Owl Creek Moun-
tains, the gypsum beds in the Triassic Red Beds are lenticular and irregu-
lar. There is much contortion of layers and considerable impurity.

Frequently the surrounding beds have forms which suggest that they
have been shoved apart by the more or less concretionary growth of the
mass of gypsum. The bedding is imperfect and the individual layers
of the gypsum are imperfectly developed, and are exceedingly variable
in thickness. It is quite possible that these gypsum beds have grown
by accretion through the deposition of calcium sulfate precipitated by
the mingling of underground brines rich in calcium chloride with sulfate
waters of meteoric origin. Some of these lenses of gypsum give the im-
pression of having been deposited in desert lakes and of having under-
gone a secondary growth after burial, in the same way that concretions
of the pure mineral type grow in sedimentary rocks by shoving the
matrix aside.

ORIGIN OF LIMESTONE CAPS

The uppermost level of a salt core commonly is a bed of porous lime-
stone, which varies in thickness from 20 to over 100 ft. (6 to 30 m.)
No fossils have been observed in this limestone. Fragments of it suggest
that the limestone is of secondary origin and that it was deposited from
solution. Its deposition might be explained either on the theory of the
mixing of oil-field brines with waters containing carbonates or from the
release of carbon dioxide carried in solution by ascending brines. It is
possible also that the limestone caps may have lain above the gypsum
of salt in their original positions in the Permean or other deeply buried
formation. However, secondary limestones are rare in the Permean of
western Texas.

There are difficulties in both of these explanations. If the limestone
caps were deposited from solution, it is hard to see why they do not
extend generally down the sides of the salt cores and why the deposition
of lime did not spread laterally between the sand grains, converting the
sandstones into solid bodies of calcareous sandstone or sandy limestone,
instead of leaving them so completely friable and uncemented. In some
cases, DeGolyer says, the limestone caps extend at least a little way

CHESTER W. WASHBURNE 275

down the sides of the domes and have what appears to be a "thimble
shape."

The theory that the limestone caps rose on the top of intrusive masses
seems hard to accept, because there is practically no evidence of the
breaking up of the cap by faulting or brecciation, which would seem to
be a necessary accompaniment of its ascent at the top of the intrusive
salt plug. The cap rock, however, may be broken and fissured more
than is commonly thought, since in studying Coastal well logs one can
recognize only large displacements. The locally high production of oil
or sulfur from the cap rock may be an indication of brecciation or ex-
tensive fissuring.

Limestone caps do not characteristically occur in great thickness
above the salt and gypsum beds that have been explored in Germany
and other foreign fields. Thin caps of this kind occur in some places
above thick beds of rock salt, but I do not know of any salt mine in
the world where there is a cap of secondary limestone that approaches
the thickness of these caps on the salt cores of the Gulf Coast. The origin
of the limestone caps of the salt cores remains an open question.

Lately, DeGolyer 11 has suggested that the calcium carbonate of the
cap rock may have been precipitated by the action of sodium chloride,
basing his suggestion on Cameron's observation that very concentrated
solutions of sodium chloride can hold less calcium bicarbonate than
weaker solutions. He quotes the following figures:

SOLUBILITY OF CALCIUM BICARBONATE IN AQUEOUS SOLUTIONS OF SODIUM CHLORIDE

SODIUM CHLOR:DE, CALCIUM BICARBONATE,

GRAMS PER LITER GRAMS PER LITER

0.0 0.06

39.62 0.101

267.60 0.04

The experiments were made in equilibrium with atmospheric air.
Their direct application to the problem is weakened by our ignorance
of the amount of carbon dioxide in the underground gases that accom-
panied the solutions which deposited the limestone caps. The table
seems to allow for the precipitation of 0.061 gm. of calcium bicarbonate
per liter of salt solution when the sodium chloride in solution increases
from 39.62 to 267.60 gm. per liter. A nearly equal amount, or 0.04 gm.
of bicarbonate remains in solution. The general nature of the problem
is similar to that of the precipitation of gypsum by salt, mentioned
above. It requires the previous solution of calcium bicarbonate by
rather strong salt solutions. Although the amount of limestone that
would be precipitated by this process is small, it could build up thick

11 Econ. Geol (1918) 13, 619. Reference to Cameron and Seidell, U. S. Dept. of
Agric., Div. of Soils, Bull 18, 58-64; also Jnl. Phys. Chem. (1901) 6, 643.

276 OIL-FIELD BRINES

limestone caps in geological time, if the salt solutions penetrated far
enough through the sediments to gather nearly twice the required amount
of bicarbonate.

In other words, all present theories of the secondary chemical origin
of the substances in salt cores require extensive circulation. Extensive
circulation, by releasing artesian waters, must promote solution rather
than precipitation of salt. The gypsum and limestone may be precipi-
tated in situ. The salt must be intrusive en masse.

SOLUTION AND DEPOSITION OF LIME IN SANDS

Messrs. Mills and Wells' 2 describe processes by which calcium car-
bonate is deposited in the sands. They show that this may result either
from the mingling of waters containing calcium chloride with waters
containing alkaline carbonates, or through the liberation of carbon diox-
ide from the waters. The deposition of lime carbonates probably
explains the occurrence of the numerous non-productive or slightly pro-
ductive areas that occur in all highly calcareous oil sands. It is probably
also the explanation of the presence of cap rocks on the tops of pay sands.
Nearly all drillers believe that there is a hard streak, or cap rock, along
the top of nearly all productive oil sands. This belief is so universal
that it must be based on fact, but the origin of the cap rock remains to
be explained. The writer is unable to advance any reason why lime
cement should be deposited between the sand grains along the tops of
the sands or in the immediately adjacent base of the overlying shale.

Calcareous sands, commonly, are firm hard rocks at the outcrop, but
most oil sands in Oklahoma, California, and the Appalachian fields
appear to be much softer and more easily drilled than the water-bearing
parts of the sand or the cap rock. The writer has regarded this as at
least an indication that the carbonate cement had been dissolved out by
circulating water previous to or during the time of concentration of the
oil in the sand. The effect may be due also to the deposition of carbonate
in parts of the sand near the outcrop and in parts of the sand remote
from production.

Further evidence of the solution of calcareous matter in oil sands is
furnished by the general absence of fossil shells from these sands. It is
often observed that fossil shells are absent in the outcrops of oil-saturated
sands, although casts of fossils may be common. Hoefer has recorded
this same fact as characteristic of all oil regions. Fossil shells appear
to be found in the outcrops of oil-saturated sands only where the sand
consists mainly of calcareous material. In these cases there was prob-
ably more calcite present than the solution could remove. The only ex-
planation of this solution of calcite that the writer has observed in

" U. 8. Geol. Survey Bull. 693 (1919) 50, 100.

CHESTER W. WASHBURNE 277

previous literature is Hoefer's hypothesis that the carbonate is dissolved
by the waters associated with the oil because of the liberation of carbon
dioxide formed by slight oxidation of the oil, possibly aided by solution
in the organic acids that exist in traces in many oils.

This explanation does not appear to be wholly adequate. The reac-
tions given by Mills and Wells 13 for the hydrolysis of magnesium car-
bonate and magnesium chloride, resulting in the formation of free car*
bon dioxide and hydrochloric acid, would explain the solution of calcium
carbonate very readily, as shown by the following equations:

MgC0 3 + H 2 = Mg(OH) 2 + C0 2
CaC0 3 + H 2 C0 3 = CaH 2 (C0 3 ) 2
Also,

MgCl 2 + 2H 2 = Mg(OH) 2 + 2HC1
CaC0 3 + 2HC1 = CaCl 2 + C0 2 + H 2 0.

Both of these reactions probably would result in the deposition of
magnesium carbonate in the place of the dissolved calcium carbonate,
but Messrs. Mills and Wells cite an example in which crusts of calcium
carbonate were dissolved from the water jackets of gas engines by pump-
ing brines rich in magnesium chloride through the jackets. The reactions
take place readily in warm solutions and they probably operate very
slowly in cold solutions.

There is a translation or diffusion of dissolved calcium carbonate
through the water in an oil sand, from points of solution to points of
deposition. As long as the water is in contact with calcium carbonate,
it must be nearly saturated with that substance. It is probably capable
of dissolving small particles of calcite and of depositing the dissolved
carbonate on larger masses, as in the process of laboratory "digestion"
to increase the size of precipitated crystals. This appears to be the main
cause of the growth of concretions in shale and sandstone. That the
process may be extensive is proved by the abundance of concretions in
many formations, including shales that appear almost impervious. The
magnitude of the process is demonstrated also by the occurrence of great
concretionary masses, scores of feet across, found in some of our western
formations. These must have drawn their supply of carbonates from
considerable distances. The transfer of carbonate through sands may
be due either to the movement of the water or to the diffusion of dis-
solved^carbonates and bicarbonates through the water, or to both proc-
esses combined.

The solution of calcium carbonate would be promoted by the presence
of magnesium chloride, as shown by Mills and Wells, and magnesium
would be exchanged for calcium in solution. The formation of dolomite
in this way has long been regarded as a cause of the porosity of the oil

" U. S. Geol. Survey Bull. 603 (1919) 72.

278 OIL-FIELD BRINES

pay of the Trenton limestone of Ohio and of the Corniferous limestone
of the Irvine field, Kentucky. Bownocker has demonstrated that the
percentage of magnesium in the Trenton limestone increases as one
approaches an oil field, and that it reaches a maximum in the productive
area. The writer has observed that the limestone adjacent to oil-filled
crevices in the outcrop of the Tamosopo limestone of the Sierra Madre
Oriental, Mexico, is dolomitic, although the rest of the limestone, begin-
ning a few inches away from the crevices, was practically pure calcium
carbonate. This indicates that the original waters in oil fields were rich
in magnesium and that the magnesium had been lost from solution by
the replacement of calcium in solid carbonates.

This process does not explain all of the features of solution. Some
fragments of the Corniferous limestone blown out of wells in the Irvine
field, Kentucky, contain solution cavities an inch or more across. The
same is true of the cap rocks of the Gulf Coast oil fields. The presence
of these large cavities in solid limestone demonstrates that underground
waters have dissolved much calcium carbonate besides that replaced as
dolomite. It would be of great interest to students of oil geology if
Messrs. Mills and Wells would devote attention to this subject of solu-
tion of calcareous cement.

In certain oil fields the process of solution has been very extensive.
Some of the oil sands of California which are hard calcareous sands at
their outcrops are only loose, friable, unconsolidated sands in the pay
parts underground. The same is true of the Woodbine sand of Louisiana
and of many other sands. Frequently these sands are so loose that they
will flow into the wells with the oil and clog the holes. As a general
rule, nearly all oil sands are so loose that sand grains work into the valves
of the pumps and wear them out within a few months; this is more rarely
the case with pumps that lift water. It appears to the writer that there
is a general process of solution of carbonate cements in oil sands.

At the same time there is probably deposition of calcium carbonate
between the sand grains along the top of the sand and in the parts of the
sand that lie outside of the productive areas. Very commonly, the parts
of a sand that lie structurally far below the oil-producing levels are so
tightly cemented that they appear dry to drillers. There seems to be
no reason to doubt that these barren parts of the sand are filled with
water, rather than with oil or gas, and that the water is under pressure
equivalent to that in the productive areas. The only reason why the
water does not enter the wells in noticeable quantities must be because
the pores are so fine and so clogged with mineral matter that it will not
move with sufficient velocity into the wells to be noticeable. This con-
dition is true of a broad area of the Bartlesville sand northwest of the
Gushing oil field, Oklahoma. It is true also of most of the synclinal
areas surrounding Ranger, and other fields of Eastland County, Texas,

CHESTER W. WASHBURNE 279

but it is not true of the more porous "lime pays" of Stephens County.
In both the Gushing and Ranger regions, the water in the parts of the
sand immediately surrounding the productive areas will flow rapidly into
the well, but when one gets a few miles away from the productive areas
the sand is so tight that the drillers call it "dry." The natural inference
is that the solution of lime cement in the oil-producing areas of a sand is
accompanied by the deposition of interstitial calcite in the non-productive
regions.

Some persons doubt that fine pores can prevent the appreciable
flow of water into a well under the pressures which exist at depths
of 2000 or 3000 ft. (609 or 914 m.). That this is a fact they will
probably appreciate when they consider that clay shales commonly have
a porosity of 5 to 10 per cent., or about half that of the sands of the
Appalachian fields. No water is observed flowing into the wells from
these shales, and it is doubtful if any does enter except from fissures.
The main reason why fine pores prevent the flow of water probably is
the fact that there are numerous bubbles of gas scattered through the
pores. Each little bubble of gas is bordered by a capillary film of water,
which clings to the walls of the pores and requires great pressure to move
it. If one takes a fine capillary tube through which water will flow
slowly and causes a few bubbles of air to enter, like a string of beads, the
flow of water will stop, even though a much higher pressure is applied.
This is the main reason why shales are capable of sealing deposits of gas
and oil. If the pores of the shale were not filled with water, cfpillary
action would quickly draw all of the oil out of the sand into the shale.
Through capillary action and through the principle of the diffusion of
water vapor into shale described above, all clay shales must be full of
water. Migration of oil and gas across them can be only through
fissures.

INDUCED SEGREGATION OF OIL ABOVE WATER

M. J. Munn and Roswell H. Johnson independently have shown that
there will be no gravitative rearrangement or stratification of oil above
water in a sand that contains water above oil, or in a sand containing a
mixture of water and oil, unless the sand is shaken or unless movements
of some kind are set up in the sand by external action. Recent experi-
ments by McCoy strengthen this conclusion. Messrs. Mills and Wells 14
have shown that an induced segregation of this kind takes place when a
mixture of oil and water flows through an oil sand into a well. As
thought by Johnson, it is quite probable that the underground circulation
of waters may promote this segregation of oil and gas above the water
in productive sands.

14 U. S. Geol. Survey Bull 693 (1919) 94, 95.

280 OIL-FIELD BRINES

This segregation promotes the anticlinal accumulation of oil. The
process may be accelerated by leakage upward across the shale on the
tops of anticlines. In many fields there is little indication of this leakage
along the crests of anticlines, and if it occurs the oil probably is too widely
scattered in minute joints to be noticed in drilling. In sharply folded
regions, such as the Rocky Mountains, oil seeps are common on the axes
of anticlines. In these regions, as in the Salt Creek and Grass Creek
fields of Wyoming, one finds many shows of oil in drilling through the
shale, and frequently there is sufficient oil in the shale crevices to make
commercial wells. In such fields there is no accumulation of gas along
the tops of the anticlines. Many volumes of gas must be formed for
each volume of original oil; hence, all of the gas and some of the oil has
leaked out of the productive sands. Some of the oil accumulated in
higher sands, as in the Shannon sand of Wyoming; some of it is scattered
through small fissures in the shale; some of it reached the surface of the
ground. The paraffine wax and tar found along crevices at the ground
surface of the Salt Creek field probably is the residue of oil that has
leaked up from the Wall Creek sand.

Oil-field anticlines appear to be the result, mainly, of direct uplift
from the folding of stronger formations that lie at greater depths. Evi-
dently there must be much fracturing along their crests. The series of
numerous small faults that cut across the axes of Rocky Mountain anti-
clines and die out on their limbs is an indication of the type of fissures
through which most of the upward migration or leakage has occurred.
Most of the accumulation occurs in the first sands above the source of
oil. The accumulation in higher sands is in smaller quantity and the
oil generally has become heavier because of the oxidation it has suffered
en route. This upward leakage along the tops of the folds may have
been more extensive than commonly thought. It would cause circula-
tion, thereby promoting the gravitative segregation of oil above water
in the sands, in a manner similar to that which Messrs. Mills and Wells
have observed in producing oil wells.

SUMMARY *

The concentration of the brines in deep wells probably results in part
from evaporation in gas that ascends through fissures or that comes in
contact with the deep water in any way.

Water vapor, also, is transferred from sand to shale by diffusion,
when the sand is partly filled with gas. The water vapor is evaporated
from the broadly concave water surfaces in sands, and precipitated on
the relatively sharply concave surfaces in shale. This process also con-
centrates the water solutions in the sands.

DISCUSSION 281

The salt cores of the Gulf Coast could not have been formed by the
precipitation of salt from solution, because they cut across many sands
that outcrop inland at higher elevations. Any upward movement of
water at the site of a salt core would set up a vigorous artesian circula-
tion of fresh water through these sands, which would destroy the con-
centration of the ascending solutions and would prevent the precipitation
of salt. The salt cores seem to be intrusive plugs of salt.

The gypsum on top of the salt plugs may be uplifted parts of deeper
gypsum beds, or may be secondary precipitates. The gypsum deposits
in the Red Beds of our Western States appear to be primary precipitates
in lakes, but some of them show structural indications of subsequent
growth by the secondary precipitation of gypsum.

The origin of the limestone caps of the salt cores remains to be ex-
plained.

Carbonate cement has been dissolved from many pay sands, leaving
them softer and more friable than neighboring dry areas of the same sand.
The solution is probably due to the formation of bicarbonates from oxida-
tion of the oil by sulfates, etc. Organic acids may slightly assist the
solution of the cement. The entrance of brines containing magnesium
chloride would cause solution of calcium carbonate by hydrolysis, as
shown by Mills and Wells, but part of the calcite would be replaced by
dolomite.

Carbonate cement appears to be deposited along the tops of oil sands,
forming the so-called hard caps or cap rock of drillers. No reason for
this action comes to mind.

DISCUSSION

R. VAN A. MILLS,* Washington, D. C. (written discussion f). Mr.
Washburne's paper is essentially a discussion of certain parts of a Geo-
logical Survey Bulletin. 15 The problems under discussion are so difficult
to solve, and are of such scientific interest and economic importance as
to demand our continued efforts toward their study. It is to be regretted,
however, that the author has not presented more data resulting from his
own investigations. Real progress in petroleum geology at the present
stage of its development demands investigative rather than speculative
study.

Messrs. Mills' and Wells' conception of the origin of the brines asso-

* Petroleum Technologist, U. S. Bureau of Mines.
t Published by permission of the Director of the Bureau of Mines.
15 R. V. A. Mills and R. C. Wells: Evaporation and Concentration of Waters
Associated with Petroleum and Natural Gas. U. S. Geol. Survey Bull 693 (1919).

282 OIL-FIELD BRINES

elated with petroleum and natural gas in the Appalachian fields is sum-
marized as follows: 16

Marine water of sedimentation and ground water from other sources have been
included and deeply buried in the sediments, where, in association with gas and
oil, they have migrated and undergone concentration, accompanied by changes in
the nature and relative proportions of the dissolved constituents. Concentration
is due in part to the leaching of the sediments by the migrating waters, but mainly
to the evaporation of water into gases that are moving and expanding through natural
channels. Reactions between the dissolved constituents of different types of waters
and between the dissolved constituents of the waters and the organic and inorganic
constituents of the sediments, have been important factors in the formation of the
brines, and so also have mass action and reactions due to deep-seated thermal
conditions.

The fact is emphasized that deep-seated evaporation is only one of
many factors entering into the formation of the brines. The factors
governing the formation of the Appalachian brines cannot be the same as
those giving rise to the primary alkaline waters of certain California
fields or the sulfate-bearing brines of Wyoming, Kansas, and Oklahoma.
Generalizations upon the formation of oil-field brines should follow
rather than precede intensive studies in different fields.

The diffusion of water vapor through natural gas as an attribute to
the deep-seated evaporation and concentration of the brines has also been
considered. 17 Mr. Washburne's hypothesis upon the condensation of this
diffused water vapor in shale and the influence of such a process upon the
concentration of the brines remaining in the sands is too speculative to
be accepted without substantiative field and laboratory data.

The writers of the Government Bulletin pointed out that deep-seated
concentration and precipitation caused by the evaporation of brines in
ascending gases, together with precipitation by the geochemical proc-
esses outlined in that paper, have probably played important roles in
the formation of the salt masses and associated cap rocks. These con-
ceptions hold true, no matter what theories may be regarded as best
explaining the origin of the domes. Mr. Washburne's selection of the
maximum volume of gas (at a pressure of 100 atmospheres) required to
cause the deposition of a unit volume of salt by evaporation is some-
what misleading. The fact is emphasized that as gas expands from a
pressure of 100 atmospheres to a pressure of 1 atmosphere (at constant
temperature) , the volume of the gas and hence its capacity to carry mois-
ture is increased a hundredfold. A gradual, and possibly slight, lowering
of temperature during the upward passage of the gas would make com-
paratively little difference in the evaporation effects of the ascending gas.

"Bull. 693, 6. "Butt. 693, 80.

DISCUSSION 283

As pointed out 18 1 cu. m. of gas expanding from 100 atmospheres to 1
atmosphere at a constant temperature of 40 C. would be able to evaporate
3800 gm. of water from a saturated solution of sodium chloride, thus
causing the precipitation of 1400 gm. or 658 c.c. of salt. In this case the
original volume of the compressed gas required to cause the precipitation
of 1 cu. m. of salt at or near the earth's surface would be 1500 cu. m., but
at deep-seated temperatures and pressures, the original volume of the
compressed gases required to cause such a deposition of salt by evapora-
tion would probably be less than 145 cu. m. Should the gas expand from
an initial pressure of 200 atmospheres at a temperature of 100 C., only
72.5 cu. m. of compressed gas would be required to cause the deposition
of 1 cu. m. of salt. At higher temperatures the initial volume of the
compressed gas required to accomplish this evaporation would be less
than 72.5 cubic meters.

To avoid the misunderstanding that may arise from Mr. Washburne's
paper, the entire paragraph from which he takes his data on the volume
of gas required to cause the deposition of a unit volume of salt is given: 19

On the hypothesis of a cooling brine, then, we calculate that 1 cu. m. of saturated
brine would deposit 11 kg. of salt on cooling from 60 to 20 C., whereas the same
amount of salt could be deposited from such brine, through evaporation, by the es-
cape of 790 cu. m. of gas at 40 C., 307 cu. m. at 60 C., or 74 cu. m. at 100 C. If the
gas expands a hundredfold at the temperatures mentioned, the volumes of compressed
gas required would be only about a hundredth of those mentioned. In short, the
volumes of compressed gas would have to be from 24 to 260 times greater than a given
volume of brine to leave salt as the final product under reasonably favorable condi-
tions. The volumes of gas required are 145 and 1550 times the volume of salt formed
at 100 C., and 40 C., respectively. Looked at in another way, 1 cu. m. of brine could
deposit 11 kg. of salt by cooling or 330 kg. by evaporation.

Mr. Washburne's assumption that the salt masses were formed at
temperatures not exceeding 40 C. is unjustified. Also, his statement
that the escape of the gas causing evaporation "could be only through
vertical channels which would necessarily be so free and open that there
could have been no accumulation of oil and gas at these places," does not
accord with present conditions in the salt-dome region where there are
today many natural exudations of gas though the fields are produc-
tive. In Washington and Morgan Counties, Ohio, gas is escaping from
sands only 30 to 100 ft. beneath the surface where little, if any, oil
escapes except where the oil sands are actually exposed at the surface.
Oil is being recovered from wells drilled to these oil sands only a few
hundred feet from their outcrops and at similar distances from the places
where the gases are escaping.

i*Bull 693, 84. " Bull. 693, 92-93.

284 OIL-FIELD BRINES

A concrete example of the amount of salt that may be deposited
through the evaporative effects of expanding gas is given in the Govern-
ment Bulletin. In a gas well that was "shut in" but in which there was
underground leakage of both salt water and gas, more than two tons of
salt were deposited during four months. The well cavity was filled with
salt to a height of several hundred feet from the bottom.

Mr. Washburne's generalizations upon the effects of fresh water in
the strata surrounding the salt domes do not seem to be warranted be-
cause there is no certainty as to how long these conditions have prevailed.
They may not have existed when the domes were formed; also it is a
matter of speculation as to whether the water conditions outlined are at
all general. The subject requires intensive field and analytical study in
conjunction with deep drilling.

In outlining the various theories advanced to explain the origin of
the salt domes, the authors of the Government Bulletin say:

Several European geologists have recently revived the old and long-neglected view
that salt-dome structure is due to the flow of salt made plastic by pressure. 20 Lach-
man sl calls attention to the variety of deformations found in the German salt deposits
and shows that the structural features range from those that are entirely conformable
to the strata in which the salt deposits are found to those of domes which show prac-
tically no relation to the adjoining strata, having apparently been formed by the
flowage of salt. Arrhenius 22 has discussed some of the physical and chemical problems
involved in the formation of the German salt deposits and applies the principles of
isostasy to explain the salt column in Drake's Saline, Louisiana. Before this ex-
planation can be accepted, experiments upon the plastic flow of salt, with special
reference to the effect of temperature and pressure, the action of water, and the pos-
sibility of flow by fracturing and granulation, followed by recementation and re-
crystallization are needed. Inasmuch as Arrhenius assumes that solutions have acted
to some extent as a lubricant for the movement of the salt, and also that many of the
unusual structural forms found in the German potash salts are due to rearrangements
brought about by water given off from hydrated minerals at depth, we feel that, even
if the preceding views are accepted, the evaporation of solutions by gases is worthy
of consideration.

Conditions of comparative weakness that might permit the plastic flow of salt
under great pressure would also permit the movement and probably the escape of solu-
tions and gases, especially where the movements of salt were accompanied by faulting
and fracturing of the overlying strata. Probably no one of the theories we have cited

* O. Grape : Zechsteinf ormation und ihr Salzlager im Untergrunde des hannover-
schen Eichsfelds: Zett. praK. Geol. (1909) 17, 185. E. Harbort: Geologic der
nordhannoverschen Salzhorste: Deutsch. geol.Gesell. Monatsber. (1910), 326; Richard
Lachmann: Salinare Spalteneruption gegen Eksemtheorie : Idem, 697; H. Stille:
Aufsteigen des Salzgebirges: Zeit. prak. Geol. (1911) 19, 91.

11 Richard Lachmann: Der Salzauftrieb, Halle, 1911. Separate from Kali.
(1910) 4, Nos. 8, 9, 22, 23 and 24. Studien ueber den Bau von Salzmassen: Idem.
(1913) 6, pp. 342-353, 366-375, 397-401, 418-431.

18 Arrhenius, Svante, Zur Physik der Salzlagerstatten: Meddelandenk.v. Nobel-
institut (1912) 2, No. 20.

DISCUSSION 285

will suffice to explain all the unusual phenomena of salt domes, but it is evident that
in conjunction with any of the processes mentioned the evaporation of water into
moving and expanding gas must be regarded as important.

In the light of present information, the origin of the cap rocks, gyp-
sum and limestone, may well be regarded as geochemical, according to the
principles cited by Mills and Wells 23 and by DeGolyer. 24 A geochemical
theory for the origin of the cap rocks may also furnish an explanation
for the failure of fresh waters to dissolve the salt masses. Salt deposits
in oil and gas wells are frequently covered and protected against solution
by calcium carbonate and calcium sulfate precipitated by infiltrating
fresh waters. The introduction of primary alkaline and sulfate-bearing
waters into wells to dissolve salt frequently fails to accomplish this pur-
pose. Sometimes the reactions are such as to contribute more salt to
that already in the wells, as in the reaction:

2 NaHC0 3 + CaCl 2 = CaC0 3 + 2 NaCl + C0 2 + H 2

If the solutions are not saturated with sodium chloride, the calcium car-
bonate around deposited salt protects it against solution. These princi-
ples may well apply to the cap-rock phase of the salt-dome problem.

The writer cannot agree with Mr. Washburne's generalization that the
tightly cemented sands along the tops and bottoms of productive sands
are characteristically calcareous. The examination of several hundred
samples of pay sands and their associated rocks of Pennsylvanian, Missis-
sippian, and Devonian ages in Ohio, Pennsylvania, and West Virginia
has shown the breaks and caps of pay sands to be characteristically
quartzitic and lacking in lime. In samples of sandstone and shale for-
mations from deep wells in those fields, most of the calcium carbonate
found appears to have been deposited through induced cementation sub-
sequent to the drilling and operation of wells. The analysis of oil- and
gas-bearing sands and their associated rocks and the discussion of deep-
seated waters as agents of cementation and of induced cementation 26
should make these points clear so far as the fields examined for that
report are concerned. The original lime content of the deep-seated sands
and shales has evidently gone into solution as chloride and bicarbonate.

While engaged in field work, during the preparation of Bull. 693, the
writer observed that the sandstones exposed to salt waters pumped from
old oil wells in Butler County, Pennsylvania, were being disintegrated
and rendered more porous and friable by leaching and etching.
Lumps of sandstone, the size of a man's fist, from the paths of the salt
waters trickling from the tanks around these wells, could be crushed
when slightly squeezed in the hand. The waters not only dissolved the
cementing material but etched the quartz grains. The fact that
oil-field waters are agents for the solution as well as the deposition of

23 Bull. 693. "Econ. Geol (1918) 13. Bull. 693, 16-18, 76, 44-50, 98.

286 OIL-FIELD BRINES

mineral matter is thoroughly established but, except for the work of
Chase Palmer, the geochemistry of some of the processes involved has
yet to be made clear.

In regard to the unconsolidated sands of the California fields, has not
Mr. Washburne put the cart before the horse? That sands at their out-
crops have been cemented through surface agencies in no way signifies
that the beds were ever similarly cemented at depth.

Recent experiments 26 made by the writer tend to disprove Mr. Wash-
burne ; s opinion that oil does not segregate "gravitationally " above water
under hydrostatic conditions in sands. Such segregation occurs very
readily with certain oils and brines, even in sands of extremely fine texture.
It is recognized, however, that where the segregation of oil above water is
incomplete, currents induced by the drilling and operation of wells may
cause the oil to migrate and to segregate more completely above the
water; it is this that the writer has termed induced segregation.

The principles of induced segregation are worthy of consideration
in the practical recovery of oil and gas as well as in the study of oil and
gas accumulation. It seems probable that favorably situated parts of
pay sands are enriched by induced migration and segregation. Again,
the escape of gases, oils, and waters through natural passages such as
fissures has evidently caused the migration and accumulation of the re-
maining hydrocarbons into favorable entrapments. 27 Some of the ac-
cumulations associated with faults have evidently originated in this way.
Apparently Mr. Washburne accepts these views as he repeats them in
his paper.

R. VAN A. MILLS (oral discussion). The investigation outlined in
U. S. Geol. Survey Bull. 693 was based largely on studies of the changes
in Appalachian oil-field waters incident to the drilling and operation of
wells. One of the principal changes is concentration due to the evapo-
ration of the brines in expanding gas, the brines becoming sufficiently con-
centrated to cause the precipitation of a part of their dissolved mineral
matter. Realizing that the mineral deposits in wells could not be formed
without changes in the proportions of the dissolved constituents in the
waters that contributed the deposits, the next step was to determine the
character of these changes. It was found that the changes occurred
through chemical reaction as well as through concentration. The loss
of sodium chloride is not the only change; various dissolved constituents
are lost from solution, the changes are complex, many factors being
involved.

I regard the hypothesis that diffused water vapor is condensed in the
shales as rather speculative. More data are needed to establish such a
theory.

As to the salt-dome problem; it was far from the intention of the

* Econ. Geol. (1920) 15, 39&-421. r Butt. 693, 94-95.

DISCUSSION 287

authors of the Government bulletin to attribute the formation of the
salt domes entirely to evaporation. We must attack this problem upon
a basis of the multiple hypothesis, without restricting ourselves to any
one theory. I believe that the theory of the deposition of salt due to
the evaporation of brines by expanding gases is one of the theories
worthy of consideration.

At present there is a considerable natural escape of gas in the salt-
dome region where oil is being produced; consequently, Mr. Washburne's
statement that the oil would have escaped with the gas causing the
evaporation is not upheld by present conditions. In many fields where
we now have production, we also have the natural escape of gas. In
Morgan and Washington Counties, Ohio, within a few hundred feet of
gas exudations, we have good oil production in the sands from which the
gas is escaping. We also have good oil production within similar dis-
tances of the outcrops of the oil-bearing sands. In one case, where an
operator has installed a barrel which catches oil (3 qt. in 5 hr.) from an
outcrop of the Cow Run sand, he is also producing oil from wells tapping
the same sand 400 or 500 ft. away from that outcrop.

The origin of the cap rocks overlying the salt masses appears, to me,
to be distinctly geochemical. In various parts of the Appalachian field,
waters from shallow beds, leaking into oil wells and coming into contact
with deep-seated brines, cause the deposition of mineral matter not un-
like that of the cap rocks of the salt domes. Thus in the mineral crusts
formed in oil wells, we frequently have calcium carbonate and calcium
sulfate associated with salt. Salt is occasionally coated with calcium car-
bonate and calcium sulfate. Under these conditions the dissolving of the
salt might produce pores similar to those in the cap rocks of the domes.
The failure to remove salt, by introducing fresh water into "salted-up"
wells, is frequently due to the reactions between the dissolved constituents
of the deep-seated brines and those of the fresh water introduced into the
wells. The water introduced into the wells may not only cause the pre-
cipitation of carbonates and sulfates, but may also cause the formation
of more sodium chloride according to the reactions quoted in Bull. 693.

I wish to emphasize the advisability of avoiding generalizations in
attacking these problems. For instance, it is erroneous to assume that
all of the relatively impermeable caps overlying oil pays are calcareous.
Several hundred samples of oil-bearing sands and their associated rocks
in the Appalachian fields have been found to be characteristically siliceous ;
carbonates are for the most part absent, even in the caps and breaks,
except where the sands were very shallow or where they had undergone
induced cementation subsequent to the drilling and operation of wells.

E. DEGOLYER, New York, N. Y. As I understand it, Mr. Wash-
burne objects to Mr. Mills' theory, and Mr. Mills agrees with Mr. Wash-

288 OIL-FIELD BRINES

burne, yet he answers rather extensively Mr. Washburne's arguments.
I would like to know to what extent Mr. Mills proposes his theory to
account for the salt masses.

R. VAN A. MILLS. The evaporation theory is advanced simply to
supply one of the factors entering into the formation of the salt domes.
The last paragraph of the discussion of the salt-dome problem 28 reads as
follows: " Conditions of comparative weakness that might permit the
plastic flow of salt under great pressure would also permit the movement
and probably the escape of solutions and gases, especially where the move-
ments of salt were accompanied by faulting and fracturing of the over-
lying strata. Probably no one of the theories we have cited will suffice
to explain all the unusual phenomena of salt domes, but it is evident that
in conjunction with any of the processes mentioned the evaporation of
water into moving and expanding gas must be regarded as important."
In the introduction we say that evaporation has played a large part in
the formation of the domes, but we do not say that this one theory fully
explains their formation.

E. DEGOLYER. Mr. Washburne has objected to all theories of the
precipitation of salt from solution by pointing out that the salt plugs
cut through various sand strata; and by inference, if the salt was deposited
from solution, the solution should have saturated these porous strata,
deposition of salt would have occurred and the sands also should have
been filled with salt. I think the point is well made, and the objection
seems to me to be valid against theories of deposition.

R. VAN A. MILLS. I do not remember that these points were raised
in the paper under discussion. Several years ago Mr. Washburne sug-
gested the hypothesis of concentration of oil-field brines by evaporation
into ascending gases. One of his principal reasons for rejecting that
hypotheses was the supposition that the interstices in the porous strata
would be plugged by the deposition of salt incident to the concentra-
tion. Now that has not proved to be the case. If the salt solutions
associated with oil and gas become concentrated sufficiently to deposit
tons of salt in individual gas wells before the water-bearing strata are
sealed, I think we have Mr. DeGolyer's objections answered, in some
degree, by facts. The "salting up" of strata yielding unsaturated
brines is a final stage in the plugging process. I understand that Mr.
DeGolyer also supports Mr. Washburne's objection to^the evaporation
theory based upon the diluting and leaching effects of the so-called
"artesian" waters.

i E. DEGOLYER. That was not what I intended to state; I was not
talking about artesian waters but about the deposition of the salt masses

DISCUSSION 289

from any form of solution. Mr. Washburne states that we know that
the salt masses pass through various porous strata which are now in
contact with the salt and he contends that if the salt was deposited from
solution, such solution would have saturated all of the porous strata which
it penetrated and would have deposited salt in them. If you could get
salt masses deposited from solution in a vertical core there would doubtless
have been motion of the solution through the channel which is now oc-
cupied by the salt and which penetrates various porous sand lenses, thus
giving the solution access to them. I am not talking about the solu-
tion moving through the sand, under ordinary conditions, but about
its moving into the porous strata from such a channel.

R. VAN A. MILLS. I cannot quite grasp Mr. DeGolyer's point of
view. It must be remembered that theories on the deposition of salt
from solution embrace only a certain group of the factors that prob-
ably entered into the formation of the domes. To assign undue weight
to these contributory factors and then to reject them altogether because
they fall short of their assigned values, is erroneous. It is my impres-
sion that fissures associated with the salt domes have constituted
channels for the movements of solutions and gases toward the regions
of least pressure which would be upward. New passages for these
movements doubtless have been created as the salt masses forced* their
way upward through the overlying strata.

In regard to the failure of the shallow fresh waters to prevent the
formation of the salt masses or to dissolve away these masses after they
were formed, it should be remembered that when, in porous rocks, cer-
tain natural waters having different properties of reaction come into
contact with one another, chemical reaction and precipitation frequently
cause dense cementation along the zones of contact between these solu-
tions. Thus the fresh waters coming into contact with salt brines or with
the salt masses may cause barriers to form, through precipitation and
cementation, that prevent further dilution or leaching.

W. E. PRATT,* Houston, Tex. Mr. Washburne mentions a "shell"
or hard upper crust on the top of many oil-bearing sands, for which
he has no explanation. I understood Mr. Mills to say that he had not
observed that condition.

R. VAN A. MILLS. In the Appalachian field, the shells and caps are
usually siliceous rather than calcareous.

W. E. PRATT. I am under the impression that it is a general condi-
tion. Very often the "shell" is simply more firmly cemented with cal-
cium carbonate than the lower part of the same sands. I wanted to
ask whether other people's observations bore out my impression.

* Chief Geologist, Humble Oil & Refin. Co.

VOL. UCV. 19.

290 OIL-FIELD BRINES

R. A. CONKLING,* St. Louis, Mo. The shell is usual. There may
be a little poor sand almost on top of the oil sand. In other cases, the
pay may be almost at the top of the sand. We usually have cementa-
tion, but the top part is cemented irregularly.

R. VAN A. MILLS. We have waters and rocks of different types in
different fields. I have accepted Mr. Washburne's paper as being essen-
tially a discussion of Bull. 693, which was based on field and laboratory
work in the Appalachian field, and I maintain my statement regarding
the oil and gas-bearing sands of that region. In southeastern Ohio, we
find the shallow pay sands carrying carbonates which may have been
formed partly through the escape of gases and the infiltration of shallow
ground waters which would be of the same order as induced cementation,
that is, cementation subsequent to the drilling and operation of wells.
The causes and effects of induced cementation by carbonates have been
outlined in Bull. 693.

For the most part, the caps and breaks in the deep-seated sands of
the Appalachian fields are densely cemented sands and shales that are
characteristically siliceous. Carbonates are usually lacking. I think
most of the carbonates you will find in these deep sands are due to induced

cementation.

C. W. WASHBURNE (author's reply to discussion). It is surprising
to find Mr. Mills disparaging speculation, as compared with investiga-
tion, because the part of the bulletin 29 under review is essentially a de-
velopment of the idea of evaporation of oil-field water by underground
gas, which idea first appeared as a working hypothesis in a purely specu-
lative study. 30 Mills and Wells prove the value of speculation by testing
this idea in the field and laboratory. The new facts they present will
lead many geologists to seek explanations, or to speculate. Speculation
has nothing to do with our daily work; yet it is the mind and soul of
geology. Like all science, it feeds on facts.

Caution against over-zealous application of the idea of underground
evaporation of water is found in the persistence of gasoline in crude oils ;
it is hard to evaporate water without evaporating the volatile parts of
contiguous oil. Practically all crude oils retain volatile components.
Light gasoline is absent in a few heavy crudes, such as the Topila and
Panuco oils of Mexico and the Comodoro Rivadavia oil of the Argentine.
The lightest commercial crude that has no gasoline probably is that of
the Pine Island field, Louisiana, which has a specific gravity of about 28
Baume". The light oil of the new Cat Creek field, Montana, which has a
specific gravity of 50 Baume*, is said to contain no volatile gasoline,
such as enters natural gas, but to have over 60 per cent, of heavy gasoline

* Head Geologist, Roxana Petroleum Co.

R. Van A. Mills and R. C. Wells: U. S. Geol. Survey Bull 693 (1919).

C. W. Washburae: Chlorides in Oil-field Waters. Trans. (1914) 48, 687.

DISCUSSION 291

of high initial boiling point but low ignition point, adapted to blending
with casing-head products. There is little gas with the oil, which flows
from the wells with a strange smoothness, like the oil in the southern
part of the Peabody Pool, Kansas, and much like artesian water.

Gas probably accompanies the formation of all petroleums. Where
it is absent, we may infer that the escaping gas carried away some of the
volatile constituents; cases of this kind are rare. Moreover the under-
ground waters of these fields are not very concentrated; the waters of the
gasoline-rich Appalachian province are much more concentrated. The
absence of gasoline in the rare exceptions mentioned may be explained
by assuming that no gasoline occurred in the original oil, or else that it
was of types that combined into heavier hydrocarbons.

Evaporation of oil doubtless is common at shallow depth, where the
gasoline content generally is low. However, there is too much gasoline
in deep oils to warrant the assumption that very much gas has passed
through them. The deep oil sands contain the more concentrated brines.
Hence the evaporation of water by gas passing through it in the oil
sands cannot be a very important cause of its concentration. Most of
the concentration probably took place in sands and other storage zones
far below the present oil sands. The principles of capillarity and adsorp-
tion furnish good reasons for believing that the pores of clay shales gener-
ally are wet and incapable of penetration by gas and oil, except under
unusual force, such as that of deformation. This view is confirmed by
the geological preservation of gas and oil in sands protected by shale.
The high temperature of great depth lowers the surface tension of liquids
and weakens all effects of capillarity. So far as it goes, observation indi-
cates generally greater dryness in the deeper sands and greater concen-
tration of their brines. The exceptions seem to consist of continuous
sands, such as the Saint Peter, that have artesian flow, which is diluted
with comparatively recent surface water. Any complete explanation
should take account of the fact that Lane and others have observed
similar relations in the deep mines of the Lake Superior and other dis-
tricts, where water decreases with great depth and becomes more con-
centrated. The apparent explanation is that the concentration was
induced by evaporation at greater depth and that the brines largely as-
cended to their present position.

The water in shale pores seals them against penetration by gas and
oil, but does not prevent the passage of water. Water, rather than gas
or oil, escapes through shale pores. Vertical fissures, if present, would
furnish the least resistance to the escape of water, oil, or gas; they would
also permit the ascent of gas and oil, which is otherwise impossible,
except under unusual force. Hence, the settling and compacting of
strata by loading and deformation expels water, rather than gas. The
water passes upward through the shale pores, at least until it meets a
continuous sand through which it can move laterally toward the outcrop.

292 OIL-FIELD BRINES

Any rise of temperature, as from deep burial, expands interstitial gas and
forces more water upwards. The generation of natural gas and oil must
displace water, driving it upwards. |

The following factor is more hypothetical. Any leakage from abyssal
crevices and any "sweating" through connecting pores would let the
liquids of the earth's interior press upwards against the gas and brine
in basal sediments. Juvenile water is of recognizable purity only in
regions of marked diastrophism or of vulcanism, but it seems improbable
that the rest of the earth is so tight that juvenile gas and water can not
filter very slowly into the basal strata at many places. At the tempera-
tures of great depths viscosity probably is more important than capil-
larity in resisting migration through pores. At depths of a few miles,
such abyssal gases as helium-rich nitrogen and carbon dioxides are to be
expected to escape in greater volume than water.

The ascending juvenile liquids would mix with the interstitial liquids
of the sediments and would be altered chemically in the new environ-
ment. In the course of geological time, they would force all earth liquids
some distance upwards, except where the latter are effectively sealed.
Thus in some degree they add to the ascent of rock brines, which are
driven upwards by the expansion of original gas from heating, by the
generation of new gas and oil, and by the settling and compacting of
strata from loading and deformation. A part of each brine is regarded
as connate with unknown deeper strata, rather than with the sand in
which it now occurs.

Mr. Mills says: "Mr. Washburne's assumption that the salt masses
were formed at temperatures not exceeding 40, is unjustified."
This figure was used because it is the lowest for which Mills and
Wells give the constants needed. It is too high, at least for the
probable temperature of the hypothetical precipitation at the top of
shallow salt cores; admittedly the temperature at the bottom of the cores
was much higher. Many of the salt masses reach the present ground sur-
face, except for a thin cover of recent clay. Most cores of this type are
marked by a semi-circular lake or depression within an enclosing low
ridge, suggesting that their tops have suffered solution. Many cores
are marked by a low mound, due to recent settling of the porous sedi-
ments around the compact core, or else to uplift of the latter. The
ridges encircling the lakes appear to be marginal remnants of collapsed
mounds, undermined by solution.

Recent deposition has obliterated the surface manifestation of many
domes. The region of the salt domes was characterized by an excess of
deposition over erosion throughout most of Tertiary time, when they were
formed. There is no very great break or hiatus in the record; every
Tertiary epoch is represented. The formations are so uniform in thick-
ness, distance considered, that we must conclude there was no great ero-

DISCUSSION 293

sion of 'the salt-dome region in Tertiary time. Deposition prevailed.
Post-Tertiary erosion is more important, but both stratigraphy and
physiography favor the idea that not over 100 or 200 ft. of cover had been
eroded from the salt domes near the coast. Some of the cores probably
reached the ground surface, as they do today; chemical deposition of
salt at the tops of such cores would have to take place nearly at surface
temperatures. The mean annual temperature of the region is about
25 C. so that those who favor the hypothesis of salt precipitation must
admit that much of the shallow precipitation took place at temperatures
below 40 C.

Mr. Mills thinks it too highly hypothetical to assume that when the
salt cores were formed the water of the artesian sands was essentially
of the same composition as today. What assumption could be less
hypothetical? The physiographic and structural conditions of the Texas
coast have undergone little change since that time. There has been no
diastrophism, other than small epirogenic movements. The salt cores
were formed in middle and late Tertiary time; the seacoast then lay
farther inland, but it did not cover the outcrops of the Cretaceous sands,
nor even those of the Wilcox formation. These outcrops being on land
and lying toward the source of the sediments, must have been higher
than the sea, which then covered some of the coastal belt. There is no
hypothesis involved in saying that the Wilcox sands under the salt domes
outcropped at a higher elevation inland at the time the domes were
formed. The present artesian condition of these sands is shown by many
fresh-water springs and wells. The same is true of the widespread Trinity
sand. The same artesian conditions must have existed in these sands in
mid-Tertiary time, because the character of the sediments prove that they
were derived largely from the northwest and were deposited on surfaces
that sloped in the same general direction as the present plains. There is
little hypothesis involved in the statement that, if these artesian sands
were punctured by fissures at the loci of salt domes in mid-Tertiary or
later time, they would let loose a flood of fresh water that would prevent
precipitation of salt. The first water released from a sand might be very
salty, but a continuation of the precipitation of salt long enough to pro-
duce salt masses of several cubic miles surely would draw much fresh
water from the higher inland parts of the sand. This statement seems
less speculative than that of Mills and Wells, that expanding gases
may have concentrated ascending brines, helping to precipitate them as
salt cores. The adverse conditions seem too strong for any theory of
precipitation.

Mr. Mills' attempt to nullif y the dissolving effect of artesian water by
suggesting that it may have consisted of primary alkaline and sulfate
water in which common salt is not very soluble, does not help his case.
The climate of mid-Tertiary time was less arid than at present and the

294 OIL-FIELD BRINES

ground water probably was fresher, otherwise I can see no reason for
believing that its chemical nature was different. The same formations
then surrounded the outcrops of the sands. The artesian water of the
Trinity sand is not characterized by high primary alkalinity nor by high
content of magnesium and calcium chlorides. I can find no analyses of
the water of the Wilcox sands, but I have found it good to drink in
many wells. Either water would dissolve common salt.

Mr. Mills is quite right in saying that my idea of the vapor transfer
of water from sandstone to shale cannot be adopted as proved fact.
Nothing ever is proved; things are established as true only for the time
that they satisfy knowledge. I hope only that this working hypothesis
of vapor transfer will be tested, as Messrs. Mills and Wells have tested
that of underground evaporation. Analysis of the forces exerted on
concave water films of very sharp curvature, as those of capillary water
in shale, indicates that they promote condensation of water vapor to a
greater degree than the relatively broad concave surfaces of water in
sandstone. With reversed control, on account of reversed curvature,
the principle is essentially the same as that of "digestion" and the pre-
cipitation of crystals in a laboratory beaker, or the growth of lime con-
cretions with solution of disseminated calcite in rocks or the* growth of
raindrops in clouds. The idea is sound in theory. I believe the Bureau
of Soils used it as a partial explanation of the transfer of soil water from
and to clay. Any experimental test of the idea will be appreciated.

SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES 295

Secondary Intrusive Origin of Gulf Coastal Plain Salt Domes

BY W. G. MATTESON, E. M., E. MET., FORT WORTH, TEX.

(New York" Meeting, February, 1921)

THE origin of the salt domes of the Gulf coastal plain has been
investigated by many of the most able geologists, but the problem
cannot be said to have been satisfactorily solved. Since 1860, numerous
theories have been presented, only to be discarded, at least in part, as
more complete information revealed their fundamental weakness.

Real progress toward solution dates from 1902, when Hill 1 advanced
the theory of secondary deposition of the domal materials from saturated
solutions of hot saline waters ascending from great depths under hydro-
static head along structural lines of weakness. Shortly thereafter,
Harris, 2 using HilPs hypothesis as a basis, explained the doming and
pronounced uplift associated with these salt cores as the result of forces
exerted by growing salt crystals. This was a marked advance over the
ideas of Coste 3 and Hager, 4 since no evidence of igneous intrusives, as
they assumed to explain the uplifts, had been found associated with the
domes. Harris 5 developed his theory until it offered such apparently
plausible explanations of so many details of dome phenomena that his
hypothesis and conclusions received widespread acceptance, despite
some serious objections, and today his theory, somewhat modified, is
considered by many able investigators to be the best explanation of the
origin of these domes.

The immense production of oil per acre, the recognition of the high
lubricating quality of the oil, the development and recognition of the
efficiency and advantages of oil-burning vessels, with the subsequent
exceptional demand for fuel oil, and the resultant advance in the price
of coastal crude, have been responsible for a prospecting and develop-

1 Robert T. Hill: Beaumont Oil Field with Notes on Other Oil Fields of the Texas
Region. Jnl Franklin Inst. (1902) 154, 143.

'Gilbert D. Harris: Rock Salt in Louisiana. Louisiana Geol. Survey Butt. 7
(1907) 76.

8 E. Coste : Volcanic Origin of Natural Gas and Petroleum. Jnl. Canadian Min.
Inst. (1903) 6, 73.

4 Lee Hager : Mounds of the Southern Oil Fields. Eng. & Min. Jnl. (July 28,
1904) 78, 137, 180.

6 Gilbert D. Harris : Geological Occurrence of Rock Salt in Louisiana and East
Texas. Econ. Geol. (1909) 4, 12.

296 SECONDARY INTRUSIVE ORIGIN OF GULP COASTAL PLAIN SALT DOMES

ment campaign throughout the coast country, during the last 5 years,
that has seldom been equaled when the present depth of drilling is
taken into consideration. This drilling has produced much information
relative to the peculiar characteristics of these salt domes, with the result
that several new theories of origin have been promulgated.

One of the most ingenious of these new hypotheses is that of Norton, 6
who thinks that these salt masses and their associated materials, limestone
and gypsum, have been deposited near the surface by highly saturated,
thermal, spring waters, such deposition taking place contemporaneously
with the sedimentation of the region. He presents new ideas in contend-
ing that the limestone cap rock, associated with many salt domes, is
due to deposition of calcareous sinter by these thermal springs; he also
suggests that the gypsum may result from the alteration of this calcareous
sinter through chemical reaction with acid sulfate waters and hydrogen
sulfide. He fails, however, to offer an adequate explanation of the
factors responsible for the structural deformations connected with the
salt cores so that his theories have not received the recognition they
deserve.

Kennedy, 7 in 1917, advocated practically the same theories but he
advanced a step when he contended that the domal uplift was due to
increase in volume resulting from the conversion of limestone into
gypsum. Mills and Wells, 8 shortly thereafter, supported Harris'
theory, removing one of the chief objections to it by presenting evidence
to show the effect of expanding gas on the deposition of sodium chloride
from concentrated solution. Lucas 9 later maintained that the uplift
was due to laccolithic intrusion at great depth.

Early in 1917, van der Gracht 10 called attention to the fact that
salt domes in northwestern Europe, of somewhat similar character to
those of the Gulf coastal plain, had been subjected to diamond drilling,
mining, and such extensive development that their origin had been
determined beyond much question. Their formation was ascribed to
the intrusion en masse of solid rock salt into the overlying strata, the
salt originating in deeply -buried, primary, bedded deposits, 10,060
(3040 m.), 15,000 up to 22,000 ft. below the present surface. His

Edward G. Norton: Origin of the Louisiana and East Texas Salines. Trans.
(1915) 51, 502.

'William Kennedy: Coastal Salt Domes, Southwestern Assn. Pet. Geol. Bull.
1 (1917) 34.

R. Van A. Mills and R. C. Wells: Evaporation at Depth by Natural Gases.
Abstract, Wash. Acad. Sci. Jnl (1917) 7, 309.

A. F. Lucas : Possible Existence of Deep-seated Oil Deposits on the Gulf Coast.
Trans. (1919) 61, 501.

10 W. A. I. M. von Waterschoot van der Gracht : Salt Domes of Northwestern
Europe. Southwestern Assn. Pet. Geol. Bull. 1 (1917) 85.

W. G. MATTESON 297

suggestion of considering a similar origin for the American domes was
not received with much enthusiasm until tentatively accepted by De-
Golyer, 11 in 1918, after rejecting a volcanic origin. E. T. Dumble, 12
whose investigations in the Gulf coastal plain region have extended over
30 years and have made him an authority on this area, became con-
verted at the same time as DeGolyer but it remained for G, Sherburne
Rogers, 18 of the United States Geological Survey, to propound and
apply in detail, through analogy and otherwise, the European theory to
the American domes. Since then, nearly all opponents, and some
advocates, of the theories of Hill, Harris, Norton, and Kennedy have
accepted the primary intrusive origin so that opinion now seems to be
about equally divided between this and the theory of secondary origin
from ascending saline waters.

Rarely has any theory gained so many active supporters in so short
a time, especially where there had been previously such a wide divergence
of opinion. The primary intrusive theory eliminates some of the old
difficulties of long contention connected with the previously accepted
American hypotheses and to some, this has evidently been sufficient for .
its acceptance. Washburne 14 apparently has recognized some of the diffi-
culties involved in this theory but his supporting argument fails to
strengthen the case.

The purpose of this paper is to show that the European intrusive
origin of salt domes, as applied to American occurrences by Rogers, does
not comply with facts and does not satisfy fundamental conditions as
observed in the field and is, therefore, not directly applicable; also, to
propose a theory that apparently complies with all field observations and
eliminates many of the objections to the present theories.

INTRUSIVE ORIGIN AS PROPOSED BY ROGERS

Rogers 16 contends that the salt plugs of the Gulf coastal plain are
off shoots of deeply buried bedded deposits of salt that have been subjected
to great pressure or thrust, and have been partly squeezed upwards in a
semiplastic condition along lines of weakness. He admits that he has
no adequate explanation for the formation and intimate association of the
cap-rock materials and the salt but suggests that the cap rock might have
been formed subsequent to the salt or that an overlying anhydrite bed or

11 E. L. DeGolyer: Theory of Volcanic Origin of Salt Domes. Trans. (1919) 61,
456.

18 E. T. Dumble: Discussion on paper noted in Footnote 11.

18 G. Sherburne Rogers: Intrusive Origin of the Gulf Coast Salt Domes. Econ.
Geol (1918) 13, 447.

14 Chester W. Washburne: Oil-field Brines. See page 269.

"Rogers: Op. tit.

298 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

block was brought up with the salt during intrusion. Since the presence
of nearly a hundred salt domes has been recorded in the Gulf coastal
plain province and practically all show varying thicknesses of cap rock,
the theory which postulates that nature should perform with such har-
mony and cooperation as to provide an overlying bed of anhydrite at
just the specific point of intrusion for every salt-dome occurrence is
constructed on rather a precarious foundation of probability.

Rogers prefaces his discussion by admitting that any acceptable
theory must consider and explain plausibly:

1. The source of the salt and the manner in which it attained its
present position.

2. The sharp local upthrust of the sediments surrounding the salt core.

3. The source and relations of the gypsum, anhydrite, limestone,
dolomite, and sulfur usually found above the salt.

4. The alignment of the domes and their relationship to the main
structural features of the region.

5. The origin and mode of accumulation of the oil associated with
most of the domes.

In attempting to prove his theories, four points are cited by Rogers 16
as favoring his hypotheses ; namely :

1. The sharp local doming of the sediments above the salt doming
of a type that several writers have stated is known to have been produced
elsewhere only by (igneous) intrusion.

2. The flow structure, crystal orientation, and cleavage of the salt
itself, indicative of pronounced movement in a vertical direction.

3. The plasticity of salt, which is considerable at ordinary tempera-
tures and increases rapidly with heat.

4. The clear evidence that similar domes in other countries have
actually been formed under the conditions postulated.

In addition, Rogers admits that the proof of his conclusions and the
acceptance of the primary intrusive theory depends on the ability to
show: A reasonable possibility that bedded salt deposits exist at depth
beneath the Gulf Coast and the possibility that forces competent to pro-
duce the results observed have been operative.

Possibility of Bedded Salt Deposits at Depth Within Gulf Coastal Plain

Province

The reasonable possibility of the existence of bedded deposits of rock
salt at depth underlying the present Gulf coastal plain province is the
foundation on which the present accepted intrusive origin of these salt
domes has been erected. Eliminate this possibility and the superstruc-
ture of the theory crumbles.

" Op. tit., 468.

W. G. MATTESON 299

Rogers 17 assumes the existence of Permian salt deposits in Permian
strata underlying the Gulf coastal plain province. He concedes that
positive evidence to indicate even the existence of Permian rocks has not
been forthcoming although over a thousand deep tests have been drilled,
some of which, in the Cretaceous belt bordering the coastal plain, pene-
trated the full measure of Cretaceous rocks but failed to find underlying
beds of Permian age. The Texas Panhandle region, an entirely different
province with different conditions of sedimentation and 200 mi. (321 km.)
removed, is made up of Permian strata, which contain beds of gypsum
and salt. Rogers 18 cites N. H. Darton, who has studied the deposits of
the Panhandle, to the effect that he regards the existence of another and
similar salt-bearing basin to the southeast as conjectural but entirely
possible. In addition thereto, Rogers adds:

There is but little positive evidence either for or against the supposition that deep-
seated bedded salt deposits exist in the coastal region. Wells penetrating 4000 ft. of
Tertiary sediments have found no salt and it is evident that if any exists it is in the
Mesozoic or Paleozoic rocks. No bedded salt deposits of any consequence are known
to occur in the Cretaceous or Triassic beds and there seems little real basis for assuming
their presence. In view of the lack of positive evidence, it is perhaps permissible to
beg the question and argue that the best evidence of buried salt beds is the domes
themselves.

This seems to be arguing in a circle and is proof of the insecure and
uncertain foundation on which the theory is built. E. T. Dumble, 19
in a paper written three years previous to that of Rogers, discusses and
makes comparative notes on the occurrence of petroleum in eastern
Mexico and the Gulf coastal plain, as follows :

To the southward in Central Mexico, very complete sections are found of both
Trias and Jura, but if the waters of those periods ever reached the Texas coast, no
evidence remains to prove it.

Referring to the oil-bearing Woodbine sands in northern Louisiana,
he says:

Between this great Louisiana field on the north and the greater Mexican field on
the south, there is an interval of more than 600 mi. in which these formations are not
found within the Coastal area, unless some portion of the basal Eagle Ford shale may
represent a time equivalent, and even if that be the case, no oil deposits are found.
We have no evidence whatever of any Permian deposits southeast of the Lampasas
geanticline nor of the continuation of the Woodbine as an oil horizon as far southward
as the coast.

Dumble 's statements have an important bearing because if conditions
in the Texas-Louisiana region prevented the deposition of the Triassic and
Jurassic observed farther south, the most reasonable deduction points to

17 Op. cit., 476-477. " Op. tit., 476-477.

19 E. T. Dumble: Occurrences of Petroleum in Eastern Mexico as Contrasted
with those in Texas and Louisiana. Trans. (1915) 52, 250.

300 SECONDABY INTRUSIVE ORIGIN OP GULP COASTAL PLAIN SALT DOMES

such conditions maintaining during Permian times, thereby eliminating
the possibility of the presence of Permian strata. This conclusion seems
inevitable when the negative character of hundreds of well records are
considered.

In a much later paper, Dumble 20 agrees with Rogers as to the intru-
sive origin of the salt domes from bedded deposits of rock salt at depth,
but realizing the extremely weak nature of the foundation on which
Rogers builds his theory by assuming the presence of Permian beds,
Dumble cites what he believes is more logical evidence as to the possi-
bility of buried salt strata. From general stratigraphic considerations,
he believes there were three periods in Mesozoic and Tertiary times that
were favorable for the development of salt deposits:

The association of the gypsum, salt, and anhydrite suggest their derivation from
sea water by evaporation. The Trinity in Arkansas carries considerable beds of
gypsum, a condition which was duplicated in west Texas, where, in the Malone Moun-
tains, we have hundreds of feet of gypsum of Lower Cretaceous age. There is, there-
fore, no reason why salt and gypsum deposits of this age may not be expected in the
area of northeast Texas occupied by the interior domes.

A second period favorable for such deposits is found in the interval between the
Comanchean and the Upper Cretaceous. While we have no such positive evidence
of the accumulation of such deposits of sea salts at this period, the fact that for hun-
dreds of miles the contact between the Buda Limestone, which marked the close of
Comanchean deposition, and the Eagle Ford shows no sign of erosion proves that
during the long period that elapsed between them, the top of the Comanchean must
have remained at or near sea level and in such relation to it that no terrigenous sedi-
ments could be laid down on it. In the more littoral zone of northeast Texas, the
Buda is represented by clays and the conditions would be even more favorable for the
formation of salt basins and the accumulation of gypsum and salt prior to the begin-
ning of Upper Cretaceous sedimentation. There is every reason to believe, therefore,
that the gypsum and salt found in connection with the interior domes may have been
deposited during the Lower Cretaceous or in the Mid-Cretaceous interval.

That the withdrawal of the sea at the close of the Eocene was accompanied by the
deposition of beds of massive gypsum is clearly shown at the southern end of the belt
of the Gulf Coast Eccene on the Conchas River in Mexico. Here the Frio clays, which
are the uppermost Eocene beds and probably of Jackson age, form a large portion of
the Pomerane Mountains. They carry in their upper portion heavy beds of gypsum,
alabaster, and selenite, interbedded with clays . While similar conditions are not known
to have positively occurred in eastern Texas, it is probable that they did, and that
salt and gypsum, which occur in connection with the coastal domes, was deposited
at the time of this emergence and prior'to the deposition of the Corrigan sands.

Since the publication of the papers by Rogers and Dumble, the
development in these areas has furnished sufficient reasons for believing
that salt deposits do not exist and were not formed in the epochs outlined
by Dumble:

1. Numerous wells, scattered over the coastal plain province and drilled

10 E. T. Dumble : Discussion on Theory of Volcanic Origin of Salt Domes. Trans.
(1919) 61, 470.

W. G. MATTESON 301

as deep as 5000 ft. (1520 m.), have failed to record the presence of salt
beds although the formations in which Dumble predicts their presence
have been penetrated.

2. Deep wells, miles from the Trinity contact, have encountered
neither gypsum in quantity nor rock salt in eastern Texas.

3. Deep wells, penetrating the Lower Cretaceous on the Sabine uplift,
have given no indications of gypsum and rock salt.

4. The Cretaceous deposits of the Malone Mountains are in a belt
where Permian rocks, carrying salt and gypsum, occur in vast quantity;
no such association is known in eastern Texas. Moreover, the Malone
Mountains are in a different physiographic and stratigraphic province
and such deductions as are suggested by Dumble are dangerous and not
justified. Intimate studies of the sedimentation processes affecting the
Gulf coast province show such processes to be complex and varying in
character to such an extent that even the same formation, within short
distances, may be hardly recognizable from its lithologic character. A
good illustration is the Fleming clays, which are palustrine at their out-
crop and non-bituminous and marine a few miles south of their outcrop
and bituminous. Therefore, even if certain conditions existed in Ar-
kansas or western Texas, this fact is no safe basis for assuming similar
conditions to exist in adjacent territory owing to the factors influencing
sedimentation.

5. Recent deep tests have proved that the conditions obtaining at the
end of the Eocene in Mexico probably did not continue northward into
Texas. A well recently drilled by the Kleberg County Oil & Gas Co., 7
mi. (11 km.) south of Kingsville, Tex., to a depth of nearly 4000 ft.
(1200 m.) penetrated the Yegua clays probably at around 1850 ft. and
probably stopped in the Marine beds or the Wilcox; it showed insigni-
ficant quantities of gypsum and no beds of rock salt. Two tests of 3300
and 3500 ft., drilled by the Gulf Production Co. at White Point, near
Corpus Christi, were abandoned close to the bottom of the Yegua, half
way through the total thickness of the Eocene formations; they showed
insignificant amounts of gypsum and no rock salt. The evidence is clear
that the gypsum is thinning rapidly to the north from the Mexican
border and the salt beds presumed by Dumble do not exist. The author
recently collected fossils from the well of the Texas Oil, Gas & Mineral
Products Co., in Grimes County, which Kennedy and Dumble identified
as probably of Cook Mountain age. The author examined the samples of
cuttings taken from this well but found absolutely no evidence of rock
salt. Another well in the same county and several hundred feet deeper
records the same results. If the quantity of salt necessary for the
formation of so many salt domes existed in the form of bedded deposits,
some of the numerous, deep, wildcat tests drilled during the past 5 years
throughoutjthe Gulf coast province would record the fact. It should also

302 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

be borne in mind that gypsum and salt are not always associated together,
even if the combined occurrence is common. The presence of gypsum,
therefore, does not necessarily signify the presence of salt.

In presenting this controvertive evidence, over a thousand well logs
have been examined by the writer. Beginning with the 5000-ft. deep test,
starting at the Fort Worth limestone horizon of the Lower Cretaceous
formation at Polytechnic near Fort Worth, Tex., and including an area
as far as New Iberia, La., to the southeast, and Brownsville, Tex., to the
southwest, not one deep test, except those on defined salt domes, has
encountered deposits of salt so as to warrant the reasonable conclusion
that extensive bedded deposits of such substance existed at depth.
Hence the foundation of the intrusive theory of salt domes, as promul-
gated by Rogers, must be rejected.

Intensity of Forces Producing Intrusiort

Rogers, 21 in developing the theory of intrusive origin, states that it is
necessary to show that forces competent to produce the results observed
have been operative, and suggests three possible causes that might pro-
duce the pressure and force demanded, namely, igneous intrusion at
great depth, the weight of the overlying sediments, and lateral or com-
pressive thrust. He dismisses the first two causes as either improbable
or not sufficiently competent to produce the results observed but concen-
trates on the third cause as the most plausible, basing his belief on
analogy with European conditions. Van der Gracht 22 describes the
salt-dome area of northwestern Europe as a geosynclinal basin, in-
tensely folded and faulted. So intense has been the folding that some
of the folds have been overthrust. In discussing the Roumanian salt
domes, van der Gracht states "that orogenetic pressure was the cause of
these upthrusts is evident from the whole structure of the region. We
find, however, that fairly often the continuing lateral compression has
squeezed out the stem of the salt core, perhaps even to the extent of
separating the saline mass at the surface from its roots in the Miocene."

Evidently the lateral compression forces brought into play in the
European areas have been enormous and much more intense and complex
than anything observed in the Texas-Louisiana area, which is also mono-
clinal in structure as compared to the geosynclinal condition in Europe.
Drilling adjacent to the American domes shows conclusively that these
domes are not situated along the axes of highly compressed and arched
folds, as van der Gracht describes for Germany, Holland, and Roumania.
The disturbances in the Gulf coastal plain province apparently partake
largely of the nature of block faulting. Lateral compression on a small
scale has undoubtedly been a complement. While these disturbances

81 Op. cit., 481. "van der Gracht: Op. cit.

W. G. MATTESON 303

are probably sufficient to cause intrusion of salt masses to some extent,
the evidence is strongly against such stresses being sufficient to cause
movement of a salt plug from a depth of 10,000 to 20,000 ft. through
thousands of feet of overlying strata, as claimed by Rogers. On this
point, Norton 23 says, "If salt in regular bedding exists in Louisiana and
Texas, it has never been penetrated by the drill. If we assume that it
exists at depths greater than have been reached, and has been elevated
to the surface by an anticlinal development, the assumption is not sup-
ported by evidence that such mountain-building forces have been at
work."

Analogies between European and American Domes

So much has been said about the European domes and such constant
reference has been made to the origin, character, and the similarity of
these domes, in many ways, to the American occurrences, that it might
be well to present briefly the evidence on which the origin of the European
domes has been formulated.

1. The undoubted presence of a great thickness of upper Permian
red marls and dolomites, lying at a depth of a few thousand up to 22,000
ft., and containing a nearly continuous deposit of rock salt averaging
about 1000 ft. in thickness in the southern area of its deposition but in-
creasing to more than 2000 ft. farther north, and possibly considerably
more in deeper basins, where the original mother bed has not been reached.

2. The presence in and throughout the salt cores of the domes of
Europe of anhydrite and intercalations of valuable potassium salts such
as is found in the original beds.

3. Areas and blocks of Permian, Triassic, Jurassic, and Cretaceous
rocks exposed at or lying close to the surface, having been pushed up
through thousands of feet of overlying Tertiary and Quaternary deposits.

4. The domes occur in and along folds or faults in geosynclinal basins
where compression and folding have been very intense.

5. Lines of weakness have been developed in two main directions,
northwest to southeast and northeast to southwest; wherever these in-
tersect high uplifts occur.

To quote van der Gracht : 24

As a rule, red Permian marls and often blocks of massive Triassic sandstones or
limestones have been pushed upwards with the salt, and now appear near, or some-
times even at the surface, sometimes standing out in relief as curious red rocky hills
amidst the Quaternary plain. The most striking of these is the red, rocky island of
Helgoland in the North Sea, off the mouth of the Elbe River. . . . The main
point is, however, that invariably the rocks associated with the saline core prove that
the plug has its roots in the Permian rock salt, however great the depth of this latter
may be, even up to 20,000 feet.

23 Norton: Op. tit., 503. " Op. tit., 88.

304 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

In comparing the evidence presented by the Texas-Louisiana domes, it
is to be noted that: p

1. There is no direct, positive, or probable evidence of the presence
of deeply buried bedded deposits of rock salt nor has deep and extensive
drilling revealed a reasonable possibility of the existence of the same.

2. Potassium salts, such as are commonly associated with bedded
deposits of rock salt, are practically missing and only small quantities
of anhydrite, not at all comparable with what should accompany bedded
deposits, are observed. This anhydrite is practically always found as
part of the cap rock and not embedded in the salt.

3. Areas and blocks of older, underlying formations have not been
upthrust so as to be exposed at or to lie near the surface. The only
foreign material observed in connection with the American domes was
a small mass of red sandstone at Avery's Island, the presence of which
can be explained in various ways.

4. The American domes are on a gently dipping monocline and, in
general, orogenic disturbance has not been intense.

5. Lines of weakness have been developed in the American domes in
two main directions, northwest to southeast and northeast to south-
west; wherever these intersect, doming is apt to occur.

Thus of the five fundamentals affecting and determining the origin
of the European domes, only one is in any way similar and is duplicated
in the Texas-Louisiana area. It is true that the American domes have
cores of salt as in Europe, that the salt is overlain by gypsum and lime-
stone as in Europe, and that the deformation partakes of a quaquaversal
nature; in other words, the form and the material of the domes bear close
and striking similarity in general features, like two veins of copper, but
as the veins of copper may have widely divergent origin, so does the origin
of the European domes, according to evidence presented, vary consider-
ably from what facts observed in the field must establish for the American
occurrences.

Conclusions

The intrusive origin of the Gulf coast salt domes, as promulgated by
Rogers, is not tenable, in that sufficient, well-established, definite data
cannot be adduced to substantiate the fundamental requirements con-
stituting the basis of the theory, and the theory does not conform to nor
satisfy the numerous facts and details observed in association with the
coastal domes.

SPECIAL CHARACTERISTICS ASSOCIATED WITH SALT DOMES OF
THE GULF COASTAL PLAIN PROVINCE

Any acceptable theory relative to the origin of the Texas-Louisiana
domes must conform to and explain, even to a reasonable degree of detail

W. G. MATTESON 305

the unusual structural, stratigraphic, and mineralogical peculiarities of
these domes. A tabulated, descriptive review of their characteristics
shows the following features :

1. A core of domal materials which includes rock salt, gypsum, anhy-
drite, limestone, dolomite, and sulfur.

2. Pure rock salt forms the greater portion of the core. This salt
is generally overlain and in direct contact with a thick, massive core or
bed of gypsum. Small quantities of anhydrite are found occasionally
in this gypsum. Sometimes the gypsum is capped by a thin to thick
deposit of limestone, and limestone is generally found intermixed, in-
cluded within, and scattered throughout the gypsum. The sulfur occurs
as crystals or crystalline masses in cavities in the limestone and gypsum.
The dolomite is due to the alteration of limestone masses.

3. The salt is relatively pure; it carries no potassium compounds,
which are characteristic of bedded deposits from sea water; neither are
broken boulders or strata of anhydrite and limestone found within the
main salt mass.

4. A microscopic examination of crystals of the upper portion of the
salt sometimes shows included gypsum crystals.

5. These cores of domal materials are roughly cylindrical or elliptical
in outline, their vertical dimensions often exceeding their diameters or
longer horizontal axes.

6. The cap-rock material of gypsum and limestone does not overlap
the salt mass to any extent.

7. The domal core is gently rounded to flat on top with dipping sides
of 60 to 90 degrees.

8. Stringers, sheets, or pencils of salt and gypsum are sometimes found
projecting from the main core; sometimes these minor deposits appear to
be completely disconnected or severed from the main core.

9. Domal materials appear to be localized and are not found in
isolated quantity at any distance from the domal core with the possible
exception of limestone. Limestone so found is part of a stratigraphic
unit and is not of the same lithologic character as the domal material.

10. Crystals of salt sometimes show elongation in a vertical direction,
the salt often shows pronounced cleavage and plication, and the gypsum
is cavernous and often fractured, shattered, and broken.

11. Strata immediately adjacent to the domal core are abruptly
domed or upturned and highly inclined, and show considerable deforma-
tion. The strata dip from 20 to 50 but appear practically undisturbed
and flat lying within relatively short distances from the core.

12. The domes apparently have a definite alignment in northeast to
southwest and northwest to southeast directions.

13. Often the top of the domal material lies at or close to the surface;
at other times at considerable depth. In some instances, the salt has

YOL. 1XV. 20.

306 SECONDARY INTRUSIVE ORIGIN OF GULP COASTAL PLAIN SALT DOMES

never been penetrated and in a few cases, not even the main gypsum mass
has been encountered.

14. The presence of certain recognized horizons at or near the surface,
which normally should be found at considerable depth, indicates uplift
in the vicinity of the core of 1000 to 3000 feet.

15. Several of the domes show faulting, and radial faulting from
the core is believed to be more general than has been indicated.

16. Some domes are featured on the surface by slight to abrupt
more or less circular mounds or elongated ridges; others, by central
depressions surrounded by hills; while others are absolutely lacking in
topographic characteristics.

17. In domes reproductive of oil, the oil is found on the east, south-
east, south, or southwest side in most instances.

19. No foreign material in quantity, such as blocks and boulders of
deeply buried strata, is found in the salt.

EVIDENCE OF SECONDARY DEPOSITION

After studying these domes in the field, reviewing the features asso-
ciated with them, and noting especially from examination of numerous
logs and some surface excavations, the intimate contact relationship of
the domal materials, there remains practically no doubt that the domal
materials are secondary in character; that they have been formed under
similar conditions of time and deposition, and that any acceptable theory
of origin must explain this type and intimacy of relationship and the proc-
esses whereby it has been developed. In other words, no theory is ac-
ceptable that explains the origin and position of the salt and not that of
the cap rock.

Attention has been called to the fact that practically no potassium
or allied salts, common to original bedded deposits or deposits resulting
from the evaporation of sea water, are present and alternations of beds
of salt, gypsum, anhydrite, and limestone are unknown. Neither is the
salt core to any extent contaminated or intercalated with silts, muds,
or any foreign deposits or substances but is so relatively pure that
deposition from solution appears to be conclusive. The author knows
of no single instance where the cap-rock material is completely and wholly
separated from the main salt core by intervening sedimentation or strata.
There are instances, as at Barber's Hill, where the drill has encountered
boulders of gypsum in sand when drilling through the cap rock and also
salt, intermixed with sand, but more extensive drilling has shown the
cap-rock material to lie in direct contact with the salt, pointing to deposi-
tion and formation in one period.

W. G. MATTBSON 307

THEORY OF SECONDARY INTRUSIVE ORIGIN

Although the sponsors of the intrusive origin of the Gulf coast salt
domes did not specifically qualify the same, the author has taken that
liberty here in order to make the distinction between this and the theory
about to be proposed absolutely clear. The designation of the older
theory as primary intrusive is in conformance with the statement of
those proposing the theory that the salt so intruded was an offshoot
of an original bedded or primary salt deposit existing at great depth.
After presenting a concise statement of the -secondary intrusive origin
of the Gulf coast salt domes, it is proposed to discuss the facts and
arguments supporting and proving the same.

The secondary intrusive origin of salt domes states that hot, saline,
saturated to supersaturated solutions or brines, accompanied by vast
quantities of gas, ascending along lines of structural weakness, deposited,
by the action of various and several agencies hereinafter discussed, the
domal materials relatively near the surface; that the initial period of
movement and uplift, caused by the force of growing crystals and the
increase in volume in the conversion of limestone to gypsum, occurred
contemporaneously with the formation of the domal materials and
sedimentation, causing gradual uplift locally as the surrounding area
was sinking; that erosion over a considerable time interval ensued,
removing part or all of the sediments capping the domal materials and,
in some instances, portions of the domal material itself, to be followed
by another period of sedimentation, deposition, and uplift, with several
minor phases, during which time sufficient lateral thrust and compression
was operative to cause gradual upward movement or intrusion of the
domal materials en masse into the overlying strata, producing thereby,
together with the first period of uplift, the deformation, doming, and
general conditions as observed at the present day.

Origin and Formation of Domal Materials

Kennedy, 25 Washburne,* 6 DeGolyer, 27 Deussen, 28 Norton, 29 and
others have conceded the secondary nature and origin of the gypsum
and limestone cap rock overlying the salt of the coastal domes. The
intimate contact relationship, and other evidence, gained from several
years of personal examination of these domes and from the study of
hundreds of well logs, indicates that all the domal materials , including

86 Op. cit., 56.

86 Op. cit., 4-8.

87 E. L. DeGolyer: Origin of the Cap Rock of the Gulf Coast Salt Domes. Econ.
Geol (1918) 13, 616.

88 Alexander Deussen : The Humble Oil Field. Southwestern Assn. Pet. Geol.
Butt. 1 (1917) 74.

89 Op. cit, 508.

308 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

the salt, were deposited under similar conditions, by similar agencies,
and closely following one another. It appears most likely that the
original domal materials consisted only of limestone, probably in the
form of travertin, and salt, the gypsum being the result of the conversion
of the limestone through the action of sulfuric acid and hydrogen sulfide-
bearing waters and gases. There may be some question as to which
was deposited first, the limestone or the salt. Norton 30 gives strong
evidence to support his contention that the limestone was precipitated
and then the salt, but Kennedy takes the opposite view. Norton states
the reasons for his conclusions as follows:

Hot ascending solutions, containing calcium and magnesium carbonates, sodium
chloride, carbon dioxide, with varying amounts of hydrogen sulfide, mingled with the
artesian saline waters of the Cretaceous beds. These waters were forced to the sur-
face by the hydrostatic head of the region, through channels that were opened by
faulting, etc.

Great deposits of travertin or calcareous sinter, similar to the deposit at Winn-
field, La., were formed around the thermal springs that issued from these openings,
the sinter continuing to build as long as the hydrostatic head was sufficient to main-
tain the flow .... Contemporaneously with the building of these suiters, sands
and clays were deposited around their bases. At times, owing to the suddenly
increased activity of these springs resulting from downward movement and relative
increase of hydrostatic head, the sinter accumulation encroached upon the marsh; at
other times the accumulation of sediment encroached upon the suiter.

As the suiter continued to build, coincident with the subsidence and sedimentation
of the region, the same excess of carbon dioxide in the ascending waters that prevented
a deposition of carbonates in the channel below, attacked and redissolved the bottom
layers. By the periodic rapid deposition of the sinter above and its slow, constant
dissolution below by the carbonated, saline waters, open spaces were developed that
were carried upward, hi which the salt was deposited from ascending solutions that
were supersaturated with saline' contents by the release of pressure, as well as by
evaporative losses these waters must have sustained at the surface, as the rapid sinter
accumulation checked the flow from the springs.

Kennedy 31 states:

We may reasonably suppose that the deposits carry a great many times more the
quantity of saline matter than calcic matter and this, as well as the more ready solu-
bility of the salt, would give the salt a greater preponderance in the percolating solu-
tions and under these conditions it is probable a large proportion of salt had reached
the depression or basin in which it was deposited before the less soluble lime carbonate
began to move. Evidently the two ingredients reached the basin together in unequal
proportions and then, due to this inequality, the lime remained longer in solution
than the salt. Very little lime occurs intermingled with the salt but considerable salt
remains in the lime or its gypsum condition. This no doubt accounts for the presence
of gypsum above the salt.

Several factors were concerned in the precipitation or deposition of
the salt. In the order of their probable importance, they may be stated
as follows:

Op. ait., 507, 508. Op. tit., 58.

W. G. MATTBSON 309

1. Deposition and precipitation due to the evaporative effects of
expanding gases on concentrated brines and supersaturated saline
solutions.

2. Precipitation caused by the presence of a common ion.

3. Precipitation due to chemical reaction between brines of varying
concentration and slightly different composition.

4. Deposition and precipitation due to lowering of temperature.

5. Deposition and precipitation due to lowering of pressure.

6. Deposition and precipitation due to other evaporative effects near
or at the surface.

Opponents of the secondary origin of the domal materials based their
arguments on the vast quantity of salt known to underlie these domes,
and the enormous and seemingly improbable quantity of brine required
to yield such masses through the processes of precipitation. Rogers 32
sums up some of these objections as follows:

The effect of decrease in temperature and pressure on the solubility of salt is small.
One hundred parts of water can carry 45 parts of sodium chloride in solution at 180 C.,
39 parts at 100, and 36 parts at 15. If it be assumed that the solution became satu-
rated and started to rise from a depth of 7200 ft., where its temperature would be
100 C., it would lose only 3 parts, or about 8 per cent., of its total load, and for every
ton precipitated, over 11 tons must have escaped.

The escape of the bulk of the saturated solution is not explained. No smaller
bedded deposits of salt from evaporation of these solutions are observed in the vicinity
of the domes. As some of the domes have grown within recent years and are probably
still growing today, we should expect to find great volumes of saturated salt solutions
issuing from them, yet only minor seeps of relatively dilute character are known.

The volume of ordinary sea water required to produce the salt would
be extremely great. Sixty domes, each containing only the quantity of
salt already blocked out at Humble (66 billion tons) require 4000 billion
tons, which represents the complete evaporation of about 25,000 cu. mi.
of sea water. Assume that one-third of the rocks consist of material
coarse enough to allow an appreciable movement of water and that this
material has a porosity of 30 per cent., then the whole section has an
average porosity of 10 per cent. The 25,000 cu. mi. of sea water would
saturate 250,000 cu. mi. of rock, or a block 2 mi. deep, extending from
Matagorda, Tex., to Assumption, La., and stretching from the coast
northward to central Arkansas and Oklahoma, where the Paleozoic rocks
outcrop. On the other hand, if we accept Harris's theory of deposition
from concentrated brine, enough saturated brine to fill the pores in an
equal block of strata would be required.

Any legitimate objection raised by the above reasoning has been
eliminated by the recent investigations and researches of Mills 33 and

32 Op. c#., 451.

33 R. Van A. Mills and R. C. Wells: Evaporation and Concentration of Waters
Associated with Petroleum and Natural Gas. U. S. Geol. Survey Butt. 693.

310 SECONDAKT INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

Wells. They recite instances where gas wells in the Appalachian field
under 810 Ib. rock pressure have gone "dead" in 24 hr., and, on pulling
tubing and cleaning out the well, 4000 Ib. of salt were removed after which
production was again obtained. The deposition of barium sulfate and
calcium carbonate in wells is also recorded and specific attention is called
to the banded nature of these deposits. The bands look much like what
Rogers 34 terms stratification planes in the salt core at Avery's Island, and
suggest the probability that such so-called bedding is due to similar
causes and the contorted nature of these bands is the result of slight,
local, differential movements. Mills and Wells 35 note the greatly de-
creased solubility of salt in the presence of a common ion showing that,
whereas a solution free from calcium chloride and having a specific gravity
of 1.202 at 25 C. can dissolve and contain 26.43 per cent., by weight, of
sodium chloride, when calcium chloride is added up to 24.58 per cent, by
weight, only 5.63 per cent, by weight of sodium chloride remains in
solution. These investigators likewise show that a cubic meter of gas,
confined at a pressure of 100 atmospheres in contact with a saturated
salt solution at 40 C., in expanding to atmospheric pressure, would
evaporate 3800 gm. of water, which would cause the precipitation of 1400
gm. of salt. Continuing, they make the following conclusions : 36

Although it is true that the solubility of salt decreases with falling temperature,
the change is small. The amount of salt that will precipitate from 1 cu. m. of satu-
rated brine on cooling from 60 to 20 C. is about 11 kg. The deposition of 11 kg. of
salt would leave 883 kg. of water saturated with 317 kg. of salt as a brine taking
no part in the process, so that the amount of brine necessary to form a dome by
deposition due to cooling would be very large. Looked at in another way, 1 cu. m.
of brine could deposit 11 kg. of salt by cooling or 330 kg. by evaporation (through
expansion of gases).

It is not necessary that the gases escape to the surface in order to cause evapora-
tion, for in deep-seated strata, under certain conditions, especially where the beds
have undergone fissuring, gas may flow from one bed where the pressure is higher to
another bed where a lower pressure prevails. The evaporative effects of the migrating
gas would, under these conditions, be none the less important. The deposition of
constituents other than chlorides, such as carbonates or sulfates, might be caused by
evaporation, so as to produce the unusual relations sometimes observed in salt domes.
It also seems probable that where the salt masses are associated with deposits of
calcium sulfate and calcium carbonate, geochemical processes yielding sodium chloride,
together with other compounds, have been brought about through the mixing of
solutions that have different properties of reaction or through reactions between con-
stituents of certain solutions and those of the containing rocks.

Adequacy of Gas Supply to Cause Great Salt Deposition

The gases necessary to produce the enormous evaporative effect^
noted may be derived from: (1) Dry marsh gases, peat and lignitic gases,
derived from the decay of swamp matter and other vegetation; (2) hydro-

" Op. cit., 469. "Op. tit., 73. Op. cit, 92, 90

W. G. MATTESON 311

gen-sulfide gases resulting from the oxidation of iron pyrite; (3) gases
developed in the metamorphism of carbonaceous shales frequently found
associated with oil and gas deposits.

There is sufficient evidence of gas in the Gulf coast province to
indicate that the quantity demanded for the great evaporative effects
necessary has been, and probably still is, present. Thousands of seeps,
emitting marsh and hydrogen sulfide gases, are recorded over the thou-
sands of square miles of the Gulf province; and these seepages have been
in operation for a long period. The 10,000 ft. (3040 m.) of Tertiary
and Quaternary deposits is featured by vast quantities of iron pyrite,
peat, and lignite in well-defined beds or disseminated throughout the
formations. In addition, the Yegua formation alone has developed enor-
mous quantities of gas from the Rio Grande River to the Louisiana border
and beyond.

Thus, the researches of Mills and Wells have eliminated the last
barrier to the acceptance of deposition from solution as the origin of the
salt and associated materials. The deposition of the greater percentage
of salt from a saturated solution due to the evaporative effects of expand-
ing gases has been proved both as a possibility and a probability and
the presence of sufficient quantities of gas for the purposes in view has
been indicated. Such gases, combined with the five other factors enum-
erated, acting on a continuous supply of strong, saturated or super-
saturated brine over a great period of time, could unquestionably
produce the enormous salt masses observed in the domes of the Gulf
coastal plain province.

Adequate Source of Supply of Salt and Limestone

The Quaternary and Tertiary sediments of the Gulf coastal plain
province have an estimated thickness of 10,000 ft. (3040 m.) with 8000
to 10,000 ft. of underlying Cretaceous formations. Thirty to forty per
cent, of the Cretaceous deposits consist of limestones and the remainder
is composed of marls, shales, and sands. Several investigators have
called attention to the disseminated saline character of the Cretaceous
deposits. In this connection, Hill 37 made the following notation:

The fact that the water increases in temperature and salinity is conclusively
proved by a line of wells, 100 mi. in length, between Comanche and Marlin, in the
lower portion of the Cretaceous series. The same stratum which furnishes water at
both places outcrops at Comanche and supplies good potable water at almost every
atmospheric temperature. At Marlin, 100 mi. eastward, this water comes from a
depth of 3200 ft., has a temperature of nearly 140 F., and is excessively saline and
sulfurous.

A careful, lithologic examination of the Tertiary strata, composed
almost entirely of unconsolidated sands and clays, reveals numerous

* 7 Hill: Op. tit.

312 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

horizons, from the oldest to the youngest, containing numerous concre-
tions and nodules of limestone, testifying to the calcareous and alkaline
character of the sediments. Even greater is the evidence of vast quanti-
ties of saline material, disseminated throughout the formations. Investi-
gators have recorded the presence of hundreds of salines and salt licks
from the Cretaceous-Tertiary contact southward. These licks, destroying
all vegetation over them except the salt grass, are featured by the white
crusts formed at the surface in a dry period following a wet spell, when
capillary processes and evaporation bring the saline material to the top
of the ground. Generally, bare spots in an otherwise grass-covered
prairie testify to their presence. No better evidence of the widespread,
disseminated, saline character of these Tertiary sediments is desired than
the presence of these salt licks. Kennedy 38 early called attention to the
saline content of the Yegua formation and, in a more recent publication,
made the following statements: 39

The Fleming shales carry large quantities of saline and other mineralized watei s
and probably such waters have something to do with the formation of the mound.
These shales also carry lime plentifully in a carbonate form as well as gypsum. . .
Carbonate of lime goes into solution when associated with carbon dioxide in alkaline
solutions. An examination of the analyses of the soils, subsoils, clay, acd waters
of the rivers and deep wells shows the presence of alkalies in considerable quantity.
The lime of the domal materials was obtained from the leaching of the various beds
from the Upper Cretaceous to the Miocene and probably Pliocene . . . We know
that most of our Miocene deposits carry large percentages of salt, carbonate of lime,
and organic remains . . . Moreover, there is an abundance of saline matter through-
out the Gulf coast Tertiaries to account for the salt found in these mounds, enor-
mous as it is.

Direct field observations and theoretical considerations present con-
clusive evidence of the existence of conditions favorable to the deposition
of lime and salt. DeGolyer, 40 in calling attention to the experiments of
Frank K. Cameron, notes that calcium bicarbonate has a solubility of
0.06 gm. per li. in solutions with no sodium chloride, a solubility of 0.101
gm. per li. in a solution containing 39.62 gm. of sodium chloride per liter,
and a solubility of only 0.04 gm. per li. in a solution containing 267.6 gm.
of sodium chloride per liter. Thus calcium carbonate is less soluble in
concentrated brines than in pure water. There is no doubt that these
conditions obtained during the deposition of the mound materials.
The high alkaline and carbon dioxide content of the hot, ascending brines,
due to the leaching of thousands of cubic miles of soils, rich in alkaline
earths, would hold the lime in solution until near the surface, when the

M William Kennedy : A Section from Terrell, Kaufman County, to Sabine Pass
on the Gulf of Mexico. Third Annual Rept. Geol. Survey of Texas (1891) 43.

William Kennedy: Coastal Salt Domes. Southwestern Assn. Pet. Geol. Bull. 1

(1917) 54, 57.

E. L. DeGolyer: Origin of the Cap Rock of the Gulf Coast Domes. Econ. Geol

(1918) 13, 616.

W. G. MATTESON 313

escape of the carbon dioxide and the supersaturated saline condition
of the brine would cause rapid deposition of the lime, probably in part
as travertin. In discussing the rapidity of such sinter accumulation,
Norton 41 quotes Geikie as follows:

The travertin of Tuscany is deposited at the Baths of San Vignone at the rate of 6
in. a year, at San Filippo 1 ft. in 4 mo. At the latter locality, it has piled up to a
depth of at least 250 ft., forming a hill 1^ nri. long and ^ mi. broad. Another illus-
tration of the rapidity with which the travertin may be deposited is furnished by the
Eocene sinter of Sezanne, Marne. This deposit contains hollow casts of flowers which
fell on the growing sinter and were crusted over with it before they had time to wither.

Norton 42 refers to a notation by Veatch of an outcrop of gray,
granular, sandy limestone, containing very imperfect plant impressions
at Drakes's Saline and to Vaughn's statement that near Atlanta, in
Winn Parish, there outcrops a hard, blue limestone which is traversed
by minute fissures and in which Veatch found impressions of dicotyle-
donous leaves, Norton regarding all such limestone with leaf impressions
as non-marine and not having been formed in the ordinary way. The
great deposits of limestone and sinter at Winnfield, La., have already been
cited and Kennedy, 43 in 1902, called attention to the deposition of
calcium carbonate from salt springs at High Island. It should be noted
that no such quantities of limestone observed capping some of the
coastal plain salt domes are found anywhere associated with the Euro-
pean salt domes strong testimony of different conditions of origin and
formation.

Frank K. Cameron, 44 during his soil researches for the Government,
conducted a series of experiments which proved that beyond a certain
point an increase in the sodium-chloride content of salt brines caused a
decrease in the solubility of gypsum. On this basis, DeGolyer suggests
that the cap rock was precipitated from solution by circulating cal-
cium-sulf ate-bearing waters coming in direct contact with the salt plug
after the formation of the latter, the salt content of the calcium-sulfate
waters being thereby increased to the point demonstrated in Cameron's
experiments as necessary to cause deposition. The vital defect in this
process is the formation of a protective covering of gypsum cap rock
over the top of the salt in a short time, after which the circulating calcium-
sulfate waters would have difficulty in coming in direct contact with the
salt core and effecting the necessary concentration to cause the precipi-
tation of sufficient gypsum to account for the masses 300 to 1000 ft.
(91 to 304 m.) thick now overlying the salt in the various domes.

Norton : Op. tit, 510.
0p. tit., 507.

C. W. Hayes and William Kennedy: U. S. Geol. Survey Bull 212.
44 Frank K. Cameron: Solubility of Gypsum in Aqueous Solutions of Sodium
Chloride. U. S. Dept. of Agriculture, Division of Soils No. 18, 25-45.

314 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

Rogers 45 also questions this theory due to the fact that examination of the
analyses of waters in the Gulf coast province shows them to be surpris-
ingly low in calcium sulfate.

In supporting the primary intrusive origin of the salt domes, Wash-
burne 46 recently gave several reasons why the formation of the salt cores
through deposition from supersaturated brines is impossible: That the
escape of gas at the locus of any dome in sufficient quantity to account
for the deposition of salt through the evaporative action of expanding gas
would keep the vertical channels so free and open that there would be no
accumulation of oil and gas at these places; also, that since the salt cores
are at least a few thousand feet in vertical dimension, they 'cut so many
water-bearing sands that the possibility of ascending, saturated solutions
maintaining sufficient concentration to effect precipitation is doubtful
due to the mingling of fresh artesian waters or dilute brines from these
water-bearing sands with the saline-bearing brines. He even states that
the cutting of fresh-water sands by these vertical channels would permit
such meteoric waters to enter the channels and not only prevent deposi-
tion of the salt but would probably dissolve any salt already deposited.

Washburne's contentions can be easily eliminated from the problem.
The oil and gas did not accumulate on and around these salt domes in all
probability until some time after the core was formed, so that free and
open channels would in no way affect the problem of petroleum accumula-
tion. Neither would these vertical channels cut fresh -water-bearing
sands capable of releasing artesian flows that would dilute the ascending
solutions of concentrated brines beyond the point where precipitation of
salt and other materials would be possible. Meteoric waters are seldom
found in the Gulf coastal plain province below 1500 ft. (457 m.) and all
water-bearing sands to this depth immediately adjacent to these domes
are lenticular in character, and, therefore, strong artesian flows are not
observed. Even if such artesian flows occurred, their volume would be
so small, in comparison with the volume of saturated brine ascending
from a depth of 5000 to 20,000 ft. under several thousand feet of hydro-
static head, that such fresh waters could have little quantitative effect.
Mills and Wells 47 have shown that these dilute, meteoric waters often
contain calcium chloride, which decreases the solubility and causes the
deposition of sodium chloride. These investigators also quote instances
where fresh water, introduced into gas wells plugged by salt, failed to
dissolve materially this substance.

The lenticular nature of the water-bearing sands is acknowledged by
Washburne who states, however, that there are some sands of widespread

41 G. Sherburne Rogers : Intrusive Origin of the Gulf Coast Salt Domes Discus-
sion. Econ. Geol. (1919) 14, 179.

* Chester W. Washburne: Oil-field Brines. See page 269.
Op. cit., 73.

W. G. MATTESON 315

coDtinuity which outcrop much farther to the north and which would
answer his purpose. Hill has shown that fresh waters entering such
sands at their outcrop become highly saline in character in a relatively
short distance from the outcrop. Washburne suggests two additional
reasons that might prevent meteoric waters from entering the open
channels along which the supersaturated brines might be ascending:
First, the pores of the sands next to the fissures might be clogged with
salts; Mills has shown that this actually happens. Second, the gas
pressure may keep the water from entering the fissures. Harris 48 adds a
third reason: "The compacting and slickensiding of the deposits about
the lower main part of the core would tend to debar the close approach of
fresh waters, and yet leave a suture line for the ascension of brines." Like-
wise the importance of explaining logically the presence of the limestone
in any theory accounting for these domal materials is conceded by
Washburne, who abandons such explanation as hopeless, however.

Alteration of Limestone to Gypsum

The limestone of the salt domes is found in irregular masses through-
out the gypsum, and occasionally as a cap rock of limited thickness on
top of the gypsum. When a cap rock, it varies in thickness from a few
to a hundred feet, and occasionally more, and is decidedly sandy in
character, which may account in part for its resistance to alteration and
its capacity to hold oil. Spindletop and Humble have a typical lime-
stone cap rock. Considerable thicknesses of massive gypsum, however,
almost always overlie the salt, throughout which limestone is always
found, bearing such relationship to it as would be expected as a result of
alteration and replacement. Cores from Sulphur Mine, La., show the
cap rock to be composed of gypsum and limestone with cavities filled
by crystalline sulfur. At Damon Mound, according to Kennedy, 49

The line of separation between the limestone and gypsum is an extremely irregular
one. In places, large blocks of gypsum extend many feet into the limestone and in
others the lime descends into the gypsum. Although the massive beds are designated
as gypsum, they are by no means wholly sulfate of lime. Tests made of cores brought
out of a number of wells show them to be a mixture of sulfate and carbonate with the
carbonate usually in contact with the sulfate.

Examination of the cores at Bryan Heights shows the gypsum to
contain numerous, irregular masses and nodules of limestone and oc-
casional barite. The limestone is soft and porous and both the limestone
and gypsum contain cavities filled with crystalline sulfur. Enormous
quantities of hot waters containing free sulfuric acid and hydrogen sul-
fide are observed at this dome. Hot water, carrying free sulfuric acid,
and great volumes of hydrogen sulfide are known at Sulphur Mine, La.

Harris: Op. tit. Op. tit. (Assn. Pet. Geol.) 50.

316 SECONDARY INTRUSIVE ORIGIN OP GULF COASTAL PLAIN SALT DOMES

There is little question that the sulfur is the result of secondary action
and has been deposited from solution.

Constantly accumulating data present convincing evidence that the
gypsum of these salt domes has resulted largely through the alteration of
limestone due to the action of waters carrying free sulfuric acid and
hydrogen sulfide. The writer has examined many cuttings from various
formations of the Gulf coastal plain province and has been impressed with
the quantity of disseminated pyrite present. Sour springs and waters
carrying free sulfuric acid are observed in connection with these domes
today. Hill 50 has mentioned the sulfurous character of the Cretaceous
waters at Marlin. Hydrogen sulfide, in great quantity, is also of general
record throughout the coastal plain region.

There is absolutely no question of the superabundance of sulfides
which may, through oxidation, supply vast quantities of acid-bearing
waters, suitable in character to convert the limestone into gypsum. One
is impressed with the correctness of this conclusion when recalling that
investigators of international repute have shown that massive gypsum, so
extensive and in such great bodies as observed in connection with these
coastal domes, has been formed generally through the alteration of
limestones. Grabau 51 agrees with I)ana that the gypsum masses of the
Salina formation of New York result from the alteration of limestones by
acid-sulfate waters, which abound in the formation and which have re-
sulted from the oxidation of iron pyrites in the rock. He adds, "the
occurrence of gypsum in the dolomites overlying the salts at Goderich,
Canada, is probably explained in a similar manner and the gypsum
deposits of Nova Scotia have been attributed to the action of sulfuric
acids on marine limestones." Kennedy 52 states that "at Damon Mound,
the gypsum has the appearance of being the altered end of the massive
limestone beds found at the southern end of the mound. Two limestone
beds having a thickness of 70 and 650 ft., respectively, are reported from
the southern end, lying between 260 and 1180 ft.; % mi. north, the gyp-
sum beds are 378 and 409 ft. thick with 30 ft. of sulfur and sand between."

Of course there is the possibility that the gypsum has been deposited
from the same brines carrying the salt. Attention has already been
called to DeGolyer's statements that the solubility of gypsum in aqueous
solutions decreases with a constantly increasing concentration of sodium
chloride. Harris also points out that the solubility of gypsum in aqueous
solutions is rapidly decreased when the salt content is reduced below 14
per cent. The writer has recently obtained data at High Island which
suggest that the precipitation of salt from saturated to supersaturated

"Op. tit.

" A. W. Grabau: "Principles of Salt Deposition" McGraw-Hill.

11 Coastal Salt Domes. Southwestern Assn. Pet. Geol. Bull. 1, 50.

W. G. MATTESON 317

brines is so complete that such dilution, favorable to the subsequent
precipitation of gypsum, is actually obtained.

However, the cavernous condition of the gypsum, its spongy character
in many instances, and the presence of cavities lined with sulfur crystals,
point to the action of waters, and the presence of waters of the necessary
character has been recorded. These facts in connection with the dis-
seminated condition of the limestone in and throughout the gypsum,
both as small grains and irregular masses of varying size and indefinite
outline, and the irregular projection of gypsum into limestone and lime-
stone into gypsum where a definite limestone cap rock is observed, point
strongly to alteration and replacement processes; in fact, no other theory
could logically explain such conditions and association.

Initial Period of Movement and Uplift

Abundant evidence exists that the salt domes have been subjected
to more than one period of movement. Deussen 53 states that the
evidence is plain that the growth of the salt core is not one growth, but
the result of several movements at different times, as shown in the
Anderson County domes. The coastal domes also have two distinct
movements.

The initial movement probably occurred contemporaneously with
the formation of the domal core and continued for some time thereafter.
Three factors were involved in this uplift; namely, the increase in volume
resulting from the alteration of limestone to gypsum, the forces of growing
salt crystals, and the general subsidence of the region.

An increase in volume of 32 to 50 per cent, occurs when limestone is
converted into gypsum. Since the gypsum shows a varying thickness
of a few to several hundred feet, and since part of the gypsum has prob-
ably been removed by erosion in some instances, it can be estimated
conservatively that an uplift or doming of 200 to 300 ft. would result
from this factor alone. That the forces of growing crystals would also
be a factor in doming is evident but it is quite probable that the extent
of uplift due to this cause alone has been greatly exaggerated.

There is slight doubt that the domal materials were originally depos-
ited relatively near the surface. The thickening of the same formations
away from the domes, which can hardly be accounted for except that the
first two factors of uplift were probably sufficiently active to cause uplift,
which prevented deposition of sediments to some extent on top of the
dome while subsidence of the immediately adjacent areas permitted con-
tinuous sedimentation and deposition and at least apparently increased
the extent of the initial uplift, is direct evidence of near surface precipita-
tion. Conditions observed at many of these domes indicate an uplift

63 Op. tit., 84.

318 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

of 1500 to 2500 ft. (457 to 762 m.) yet nothing in the character of the erogenic
movements affecting the coastal plain province points to forces capable
of producing such displacement being generally active. It therefore seems
probable that part of this uplift is the result of nicely balanced conditions
of sedimentation wherein initial forces of uplift were sufficient to keep
pace or overcome the general subsidence of the region; this resulted in
formations near the domes being considerably elevated compared with
the same formations away from the domes.

Recently the writer made an examination at High Island. On the
south side, an area of one or two acres has been designated as the " trem-
bling marshes/' because the crust, when traversed, would shake or tremble
over a considerable distance in a manner similar to the shaking of quick-
sand. Eighteen years ago this area was a slight depression in which
animals would bog; today, it is a mound, about 3 ft. higher than the
surrounding territory, composed of crystals of salt. Salt is being depos-
ited there by springs and the run-off, after deposition, is much less saline
than ordinary ocean water. The writer regards this evidence as most
important. Kennedy 54 records the deposition of carbonate of lime from
springs on the west side of the Island together with the salt. Is not this
an illustration of the processes which resulted in the formation of the domal
materials and caused in part the initial uplift?

Subsequent Periods of Movement and Uplift

The formation of the domal materials and the initial period of uplift
in the Texas-Louisiana coastal plain province was followed by general
subsidence of the entire region and a long period of sedimentation.
During this time, minor movements of uplift might have occurred but
on such a small scale as to be hardly noticeable.

Subsequently a series* of movements and uplifts occurred as the
direct result of isostatic readjustments and the action of orogenic forces
of some magnitude. These forces acted along old fault planes and other
lines of weakness and undoubtedly were accompanied by considerable
lateral thrust. As a result, the salt cores were thrust upwards and
intruded into the overlying strata. The entire period of movement was
gradual and probably extended over a considerable time interval. The
direct result was the fissuring of the cap rock, the possible production on
a small scale of plications within the main salt mass, the possible recrys-
tallization of the salt, and the production of cross and radial faulting
around the dome. It was these subsequent periods of uplift which pro-
duced the abrupt upturning of the strata as well as the shearing and
piercing of the same now observed around these salt cores. The com-
bined uplift undoubtedly produced marked surface doming. During

"Hayes and Kennedy: U. S. Geol. Survey Bull. 212.

W. G. MATTESON 319

this period, erosion was again active and continued some time thereafter.
Subsequently, subsidence occurred and recurred, and sedimentation was
resumed on such a scale as to eliminate completely the remaining topo-
graphic features of these domes. These subsequent periods of uplift
varied for different series of domes but occurred at various intervals from
the end of the Cretaceous era to the present time. In the case of the
commercially important oil-bearing domes immediately adjacent to the
present Gulf coast, the major portion of the subsequent uplift occurred
near the end of the Miocene and into Pliocene time as we find the Miocene
formations pierced and deformed with the domal materials often intruded
into the overlying Pliocene, which has been steeply arched.

During the subsidence that followed, Beaumont clays of Pleistocene
age were deposited over this area, completely obscuring the topographic
features of these domes. Another period of gradual uplift then began
and has continued up to the present time; it has been general in char-
acter and is still in its early stages. Its important significance has been
the development of slight mounds, hills, or ridges at the loci of domes in
a number of instances where the forces have been locally more intense
and especially where the domal materials are close to the surface. At
points where the domal materials are deep lying, local mounds or ridges
due to uplift are generally absent, suggesting that the forces of uplift
have so far been absorbed by the un consolidated overlying material
without deformation. Erosion may account for the absence of mounds
and ridges in some instances. This topographic expression has been
one of the most reliable characteristics in determining the locus of a
salt dome and domes are now classified in the field according to topog-
raphy, as:

Domes of the first class with definite, characteristic, topographic
expression in the form of low, roughly circular to elliptic mounds or
ridges, rising 10 to 80 ft. (3 to 24 m.) abruptly above the adjacent prairie,
as illustrated by Damon Mound, Hull, and High Island.

Domes of the second class with slight topographic expression in the
form of low, roughly circular to elliptic mounds or ridges, rising 2 to 10 ft.
(0.6 to 3 m.) somewhat abruptly above the adjacent coastal prairie, as
illustrated by Spindletop, North Dayton, etc.

Domes of the third class with no domal or ridge topography but occasion-
ally with sunken depressions, featuring the locus of the salt core, as
illustrated by Goose Creek, Edgerly, or South Dayton.

OIL ACCUMULATION

The oil associated with those salt domes where commercial production
has been obtained is of Tertiary origin. This conclusion is based on the
grade of oil, the character of the accumulation, and the fact that the

320 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

Tertiary formations are petroliferous. The oil of the Texas-Louisiana
coastal plain has an asphalt base, whereas the great percentage of oil
obtained from the Cretaceous formations in this province is largely of a
paraffine base, while oil from the Pennsylvania horizons is practically
always of paraffine character.

On 90 per cent, of the producing domes, the oil is obtained from the
east, southeast, south, or southwest sides. As this is the side corre-
sponding to the normal dip of the formations and is generally the side of
gentlest dip, this fact is strong evidence of the Tertiary origin of the oil.
If the oil came from the underlying Cretaceous and Penijsylvanian
formations, migrating upward through the same channels with the saline
brines, the oil should be found as often on the northern and north-
western sides of the domes as on the normal sides.

Data gathered point to the Fleming clays of Upper Miocene age
as the original source of the oil. These clays are bituminous in character
in their seaward, marine phase underlying the present area adjacent to
the Gulf shore line. Oil in considerable quantity has been found only in
regions underlain by marine Fleming clays. Tests west of the Colorado
River in Texas, where the equivalent of the Fleming clays is a fresh-water
deposit, have failed to find oil in commercial quantity.

In discussing the Humble oil field, Deussen 65 describes the oil there
as originating in the Yegua clays and migrating upwards into the over-
lying Oligocene sands. The fossil evidence that he has presented,
though, appears open to question, and the failure of the Yegua to yield
commercial oil from hundreds of tests that have penetrated this formation
adds to the difficulty of accepting Deussen 's conclusions without more
data. However, the Yegua, Cook Mountain, and Mt. Selman formations
of Eocene age are partly or entirely marine in character, and have
exhibited bituminous phases. The Yegua has yielded dry gas in great
quantity and numerous oil showings up to 1 or 2 bbl. wells. Although
general conditions would indicate that these formations have oil-produc-
ing possibilities, the universal failure of numerous wells penetrating these
formations where structural conditions are known to have been favorable
is discouraging.

CONCLUSIONS

The intrusive origin of the Gulf coastal plain salt domes, which
postulates that the salt is of primary origin and that its configuration,
character, and position are due primarily to intrusion en masse from
bedded deposits below, is untenable, as the fundamental principles
constituting the basis for this theory are not substantiated by data
gathered from exhaustive detailed field examinations. Since the theory

" Op. tit., 73.

W. G. MATTBSON 321

was first proposed, numerous deep tests have penetrated the formations
in which conditions were most favorable for the development of beds of
salt but no such beds have been encountered over a wide area.

The analogy between the European and American domes, which has
been used to establish similar modes of origin, is one of form only and is
more apparent than real. Details, fundamental in character, indicate
that these domes must have had a widely different origin. Bedded
salt deposits of great thickness and extent are known to underlie great
areas in northwestern Europe. The salt cores there have brought up
great blocks of Permian, Cretaceous, Triassic, and Jurassic strata that
normally occur at great depths; the salt masses contain numerous inclu-
sions of silt, clays, sandstones of the typical bedded variety, alternating
beds of anhydrite, limestone, and gypsum, while analysis of the salt
shows the presence of potassium and other salts typical of original
bedded deposits. The gypsum and limestone cap rock of the American
domes is much thicker. The orogenic forces in the European area have
been most intense and, with the geosynclinal structure of the region,
have undoubtedly been of sufficient magnitude to produce the results
observed. No bedded deposits of salt have been found; no blocks of
deep-lying strata have been upthrust into younger strata, no inclusions
of bedded formations, silts, clays, etc., nor of anhydrite, limestone,
potassium and allied salts are generally observed in the American domes;
the greater portion of the salt shows a purity that can be logically ex-
plained only by precipitation from solution, definite in chemical composi-
tion and subjected to uniform conditions of chemical reaction. The
weight of the overlying strata and such orogenic forces as were operative
in the Texas-Louisiana region are insufficient to bring the salt cores to
their present position from depths of 10,000 to 20,000 ft. through intru-
sion en masse.

The secondary intrusive origin differs from the previous theory in
that intrusion of the domal materials en masse is only one of the several
factors accounting for the present position of the salt cores and struc-
tural deformation produced, the domal materials being first regarded as
secondary products, deposited relatively near the surface directly from
solutions of secondary origin and character. This theory is based
on fundamental details observed in the field; it is in conformance with
various processes still observed in operation in and around these domes;
it satisfies every detail in occurrence, character, and shape of the dome
and domal materials, and their relative positions, and offers a satisfac-
tory explanation of the formation of the cap rock, which the European
theory fails to do.

This secondary intrusive origin theory is a combination of several
theories. The writer has taken the acceptable portions of such theories
and, from data gained in several years of detailed field investigation,

VOL. LXV. 21.

322 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

has supplied the connecting evidence necessary to mold the facts and
principles into a concrete, coherent expression or explanation of the
mode of origin, in such a way as to eliminate apparently the objections
and shortcomings of previous statements on this subject, to account
for chemical, stratigraphic and structural conditions, and to satisfy all
observations of fact recorded in the fifty odd years of investigation of
these domes. The Gulf coastal plain province is one of the most difficult
areas to analyze geologically. Each dome exhibits certain peculiarities
so that extensive data become essential before general deductions can be
made and theories propounded and data of this nature can be accumu-
lated only by careful, diligent, and exhaustive investigation and study
on the part of numerous geologists.

If the secondary intrusive theory of origin should be generally
accepted, it should be remembered that such a theory has been made
possible only by the investigations of Lucas, Kennedy, Hill, Dumble,
Veatch, Rogers, and Lee Hager; the researches of Harris, Norton, Mills,
Wells, and Washburne; the intelligent and constructive criticism of
Rogers, Woodruff, and others; and the able observations of Deussen
and DeGolyer. To these geologists especially, and to many others,
credit is due for whatever intelligent understanding we possess of these
peculiar structural entities, and of this the writerjias ever been mind-
ful and appreciative, not only in the present discussion but in the
years of personal field observation conducted with a similar^object
in view.

DISCUSSION

EUGENE COSTE, * Calgary, Alberta. The author 's argument is weak
in that he attributes the enormous masses of secondary salts, liquid
hydrocarbons, and natural gas and sulfuret of hydrogen found under
the domes to the leaching of sediments. It is absolutely impossible to
admit that these large quantities of salt, limestone, silica, sulfur, sulfuret
of hydrogen, and gaseous and liquid hydrocarbons have been leached out
of the sediments in which these vertical chimneys of secondary products,
known as salt domes, are found. It is just as untenable to believe that
as it is to believe that the salt masses under the domes are derived from
big beds of salt in the lower rocks, which it has been proved do not exist.
The circulation of meteoric waters in the sediments takes place only in a
few porous beds, mostly sandstones, and the great quantities of salt,
sulfur, and other products mentioned cannot possibly come from such a
source.

* President and Managing Director, The Canadian Western Natural Gas, Light,
Heat and Power Co., Ltd.

DISCUSSION 323

We will, therefore, have to return to the solfataric volcanic view
regarding the formation of these salt domes that I advocated before this
Institute 66 about 17 years ago. We know that all through that district
and extending south to Mexico and beyond there have been orogenic
movements at different geologic periods and some in recent time. These
have resulted, in Texas and Louisiana, in great deep faults, hundreds of
miles long, from which at separate points along their course gaseous and
liquid solfataric or juvenile emanations have come up from the interior.
The faults are miles deep and have brought up these gaseous and hot
waters from great depth; in fact, from the volcanic magma below. This
is clearly the origin of all of the secondary products under the salt domes;
and in some of the domes in Texas and Louisiana, as well as in Mexico,
many of the salt waters and oils are still at high temperature.

We cannot imagine that the great masses of sulfur in Calcasieu
parish, Louisiana, for instance, can come from the leaching of sediments,
or that the natural gas can come from beds of carbonaceous shale that
have not been distilled and exist in the sediments as undistilled shales.
Such sediments will not give these products at all, especially in anything
like the enormous quantities, recognized by the author, it is necessary
to admit must have come up these chimneys, or domes, to help produce
such huge deposits of salts, etc. by the concentration of brines by evapo-
ration. These enormous quantities of gases and heavily charged brine
cannot be obtained except from the interior magma along deep faults
and these are remarkably well indicated all through that country by
the linear directions of all these deposits or salt domes.

E. W. SHAW,* Washington, D. C. We have great need for more
detailed information concerning individual salt domes. If those who
have studied them for years, have examined hundreds of well records,
and studied the outcropping rocks would tell us, for example, just what
domes are known to have salt, if all of these domes have cap rocks, if
the cap rock is ever around the sides or on the slopes of the dome, as well
as on top, and whether or not it is certain that all that is called cap rock
is of secondary origin, the height and shape of each dome as shown by
structure and convergence maps, how much indurated rock is involved in
each uplift, the composition of the cap rock from dome to dome; and
other details, we might find the basis for one or more inferences of value.
For example, if the cap rock is due to diffusion and represents a chemical
reaction arising out of the introduction of salt or some other substance
into the strata, one might expect the process to affect everything around
the deposit of salt sides as well as top.

66 Volcanic Origin of Oil. Trans. (1905) 35, 288.
* Geologist, U. S. Geological Survey.

324 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

The speaker has stated that there is evidence of sufficient gas in the
region to meet the quantity demand for the evaporation of enough salt
water to yield the enormous quantities of salt in the domes. I have not
had time to go over the figures lately, but two or three years ago I tried
to estimate about how much gas would be required and found that the
amount required for one dome was considerably more than all of the
natural gas that the United States has produced to date, as a matter
of fact several hundred thousand times as much. That is over and
above the problem of whether the salt water and necessary migration
of the salt water to the points of deposit has been, or is likely to have been,
of such a nature as to have yielded the quantities of salt.

On page 311, it is stated: "Thus, the researches of Mills and Wells
have eliminated the last barrier to the acceptance of deposition from
solution as the origin of salt and associated materials." It seems to me
that this statement is quite erroneous for two reasons. One is that when
gas evaporates salt water and deposits salt, the salt closes the pores and
the process is self-inhibiting, whether it occurs in the bottom of a well,
or in fissures or other cavities at great depth or near the surface. The
other is that enormous quantities of gas and salt water are required at the
point where the salt is being deposited.

JOSEPH E. POGUE, New York, N. Y. A few years ago I made a
hasty examination of an old salt mine in Colombia. This is a great
mass of salt near the surface, and at the time I was impressed with the
resemblance of this deposit to the Gulf salt domes in a general way.
This salt deposit was quite evidently an intrusion in the surrounding
strata, the evidence of that conclusion being the nature of the contact,
the inclusion of shale and other sediments along the borders of the salt
mass, and the general contorted character of the salt mass. My impres-
sion at the time was that the salt was forced into the surrounding rock in
much the same condition as a plastic mass of tooth paste extrudes out of
the container; in other words, the material came in from a lower level
under pressure.

F. G. CLAPP, New York, N. Y. In discussing the origin of the salt
domes, we have made little effort to take into account all known factors
concerning salt domes, to say nothing of the unknown factors. For
instance, in the case of Louisiana domes, we know that regardless of
whether or not the alignment is important and whether or not the
phenomena are deep-seated or superficial the domes are arranged in lines.
Going north into central Arkansas, we find an intersection of two lines
of volcanic phenomena, or intrusion of igneous rock, two of which rise
several hundred feet above the earth's surface. The third igneous
intrusion is about the same distance from the second that the second is

DISCUSSION 325

from the first, but not conspicuous, although fragments of volcanic
rock of similar character are found in the bottoms of gullies traversing
the region. At a greater distance from the two known intrusives is the
Arcadelphia salt dome or salt marsh. In considering the origin of the
salt domes, it seems necessary to consider whether this feature only 100
mi. or so north of Louisiana may have some bearing on the Louisiana
question.

The parallelism of salt-dome distribution with the distribution of
volcanic phenomena has been contradicted in Mexico, though not so
convincingly but that some truth may exist in this parallelism; and it is
worth while to consider whether there may not be some connection
between the two classes of phenomena.

It is a question whether all European geologists have accepted the
theory of salt having been pushed in from underlying and pre-existing
salt beds. I think the theory originated in the German fields and
possibly with the German geologists; but in the Transylvania fields many
conditions appear discordant with that hypothesis. There seems to be
no more evidence than in Louisiana that the strata were underlain by
salt beds.

In the same field there is evidence that some domes may still be
rising and I have heard that even in the Louisiana fields evidence exists
that some salt domes may still be rising. In Transylvania, one evidence
is the existence in places of salt at the surface salt not covered by
superficial deposits but by vegetation, old trees, etc., which show signs of
movement during the time of growth which at most cannot be more
than fifty years. Evidence that the folding was not limited to ancient
periods seems to exist in the pinching out of strata as they approach the
dome in some of the Red Beds in southwest Oklahoma and in the Tertiary
deposits of Transylvania. We must consider the dome problem from
a worldwide viewpoint, rather than on the basis of evidence furnished by
one field like Louisiana.

E. DEGOLYEB New York, N. Y. The indicated intention of the
author is twofold: to disprove the theory of intrusive origin of the
gulf coast salt domes and to propose a more acceptable theory. To my
mind he accomplishes neither. The bulk of his argument against the
theory of intrusive origin concerns itself with critical discussion of the
fact that we know of no bedded salt deposits in the rocks of the coastal
plain which might have served as a source for the intrusion of the salt
core or stock of the dome. This lack of knowledge of the existence of
salt deposits of sufficient magnitude has always constituted a weakness
of the tectonic theory, as well recognized and stated by its adherents as
by its opponents.

The simple fact is that we do not know whether there are bedded

326 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

deposits of salt or not. Any required by the theory of intrusive origin
would obviously lie below the salt of our known domes. The deepest
wells in the Gulf coast that have penetrated the domes have not gone
below the salt of the stock. As an example, the Producers Oil Co. well
No. 17, Block 29, of the Wheeler & Pickens Fee at Humble, penetrated
the salt stock of the Humble Dome at a depth of 2342 ft. and continued
in it to 5410 ft., where the well was abandoned without having gone
through the salt. Manifestly, according to the theory of intrusive
origin, any bedded salt deposit necessary as a source of the salt of this
stock would lie below this depth of 5410 ft. and clearly, below our zone of
knowledge.

It may be objected that the stratigraphic horizon equivalent to a 5410
ft. depth at Humble, lies at much shallower depths farther northward,
that it outcrops in fact and consequently lies well within our zone of
knowledge. This must be admitted, but other salt domes show the salt
below still lower horizons stratigraphically. In the Palestine, Texas,
dome, certainly Eagleford and probably Woodbine, the base of the Gulf
series of the Upper Cretaceous, has been recognized. The source of the
salt then must have been below this horizon and, consequently, through-
out most of the coastal plain, entirely below our zone of knowledge. The
information yielded by Mr. Matterson's examination of over 1000 well
logs is not of value in this investigation because it is not from the horizons
in which we are interested.

It seems quite probable, if the intrusive theory is correct, that the
salt domes, as we at present know them, had their origin in folded and
faulted pre-Cretaceous rocks upon which our Cretaceous and more recent
rocks lie unconformably as a masking mantle and that the salt stocks
themselves were forced upward into this more recent mantle. This is
pure speculation, but so is every other theory of salt-dome origin that has
come to my attention.

The tectonic theory is not more deficient in its failure to account for
a source of the salt than is any of the various theories of deposition from
solution. Simple explanations of deposition from natural brines, particu-
larly connate waters, whether with the assistance of gas evaporation,
as suggested by Mills and Wells, is not enough. There are many places
in the world where faults, even cross faults, are common and where brine
and natural gas are also as common as on the Gulf Coast, yet where salt
domes do not exist.

Many of Mr. Matteson's other arguments are quite faulty. His
attempt to discredit the apparent analogy between American and Euro-
pean domes will not hold. The resemblances between the two types is
much more marked than is their differences and in the Isthmus of Tehuan-
tepec region of Mexico, the differences are still further sunk since good
examples of both types are present in the same area.

DISCUSSION 327

It is not true in the American domes that " areas and blocks of older,
underlying formations have not been upthrust so as to be exposed at or to
lie near the surface" as is the case with certain European domes. The
Cretaceous is thrust up through the Tertiary in many of the north Louis-
iana and Texas domes. The Palestine dome shows such an upthrust of
the order of 3500-4000 ft. beyond any question. At Tonolapa, on the
Cececapa dome, in the Isthmus of Tehuantepec, Jurassic limestones have
been thrust upward several thousand feet, coming to the surface through
Miocene or Miocene-Pliocene marls.

Nor is Mr. Matteson more fortunate in his conclusion that the salt
of American salt domes cannot be free from bedded deposits because
" potassium salts, such as are commonly associated with bedded deposits
of rock salt, are practically missing. " Phelan 57 gives analyses of salt,
brines, and bitterns from various bedded deposits and domes in the
United States. The chemical composition of the various salts is re-
markably uniform and there is no variation between salt-dome salt and
bedded salt deposits greater than the variation between various sam-
ples from bedded deposits. The same is true with regard to natural
brines except that brines from Humble and Sour Lake, both salt domes,
show slightly higher potassium contents than other brines the direct
opposite of Mr. Matteson's argument.

The theory that Mr. Matteson proposes as a substitute is one that
includes bits from all previously proposed theories. This is its strength
as well as weakness, since many forces have probably combined to pro-
duce a salt dome. We are interested, however, principally in the main
force forming the salt dome. We might consider a dome as a structural
feature alone. Of course, the salt is common to all of them, but there
are domes that have no cap rocks, sulfur, or oil. What theory will
explain the tremendous upthrust by which blocks of sediments % or 1 mi.
in diameter are thrust upward 4000 ft. to perhaps much greater distances,
through rocks of younger age? I do not believe that Mr. Matteson's
theory will meet this test nor do I believe that any other theory of deposi-
tion from solution is sufficient.

Of course, much can be said for every theory. I do not believe, for
example, that the volcanic theory is acceptable, but it explains fairly
well some facts difficult to explain by any other theory. It explains
the hot waters associated with the domes and it is more satisfactory in
explaining the extremely high sulfur oils of coastal Texas and Louisiana,
the Tampico region, and the Isthmus of Tehuantepec region, two salt
dome regions and one region of volcanic activity, than is any other theory.

W. G. MATTESON. As to the impossibility of admitting that such
great quantities of salt could be leached from the various sediments under-

w U. S. Geol. Survey Bull. 669.

328 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

lying the coastal plain area, the researches of Mr. Kennedy have proved
conclusively that just in the Miocene deposits alone there is enough dis-
seminated salt content to account for the salt in these coastal domes.
Besides, there are the underlying formations with disseminated salt in the
Cretaceous deposits, which we know may be considerable.

Mr. Shaw questioned the advisability of having more detailed infor-
mation on the cap rock. The major operating companies in the Gulf
coastal plain area recognize the importance of geological application,
especially since the bringing in of oil around some of the older formerly
abandoned domes. Some companies have accumulated a great mass of
valuable detailed evidence. It is difficult for a consulting geologist to
get this information in every instance but this would be a good oppor-
tunity for the United States Geological Survey to bring up to date its
data on the Gulf coastal plain area. It is quite possible that several
companies would turn over a considerable portion of this information to
the Survey. The author has had access to some of this information.

Mr. Shaw raises the question of gas being present in sufficient quantity
to cause deposition through evaporation. The Yegua formation has
yielded enormous quantities of gas, and in many cases where we drilled
into that formation all we obtained was gas. The fact that gas has
been found from the Mexican border across the entire states of Texas
and Louisiana shows that the amount of gas in this one formation alone is
great; in addition there is the gas in the Cretaceous and underlying Penn-
sylvanian formations. There is an adequate supply of gas to account for
great evaporative effects on salt brines with the subsequent deposition
of vast salt masses.

In the preparation of this paper I was able to consult with Mr.
Kennedy, who has recently investigated the logs of wells of the Freeport
Sulfur Co., at Bryan Heights and some of the material presented herein
was the result of that conference.

Mr. DeGolyer speaks of the tremendous upthrust of strata at the
loci of domes. First, the changing of the limestone into gypsum results
in an increase in volume of from 32 to 50 per cent. As we find a gypsum
cap anywhere from 200 to 700 ft. in extent, and probably considerable
of the gypsum cap has been eroded, this alteration alone indicates an
initial uplift of a few hundred feet.

In presenting this paper I admit that a considerable part of the uplift
has been due to intrusion en masse, but that intrusion has occurred after
the salt has been deposited relatively near the surface along with the
limestone and other materials. The upthrust of those domes, amounting
to close to 4000 ft. in the interior domes, to which Mr. DeGolyer calls
attention, seems to be greater than the average of 1500 to 3000 ft. which
we find along the Gulf coastal plain proper, but might not that be due
to the fact that the interior domes are nearer the great Bal cones fault?

DISCUSSION 329

H. W. HIXON, New York, N. Y. There was great pressure of gas
below the cap. Where gas could not escape water certainly could not,
which shows that the seal was complete. Therefore, I do not believe it
would be possible for much water to have escaped from these domes with-
out leaving evidence of its having been present.

My theory of the origin of these domes involves a fundamental
conception of the physical condition of matter in the interior of the earth.
The temperature at a moderate depth, say 150 mi., will be a critical
temperature for all the matter in the interior of the earth; after it passes
the critical temperature it is- in a gaseous condition, and when matter
is above its critical temperature, it is capable of high compression. Gravi-
tational compression unrestrained is capable of producing, in a gaseous
core, matter that is denser than the solids that will form out of them.
Admitting, for the sake of argument, that the gaseous core can be denser
than the solids that will form out of it, we have a solid crust floating
on the gaseous core, like ice floats on water. Likewise, when matter
changes from the condition of gas denser than solids, to that of a solid,
it expands. If the gaseous core is expanded by loss of temperature, the
cold crust above will be fractured, and great fault planes, which are
called erogenic in nature, should be formed and more or less parallel.

These fault planes may be of two series, which intersect at approxi-
mately right angles. These salt domes occur at the intersections of those
faults, which furnished a passage for volatile material from the interior.
Whatever shale beds covered those fault planes did not rupture clear
through to the surface, but stretched under pressure of the load and
completed the seal. The volatile material in these domes rather confirms
that. Salt is volatile at a moderate temperature, so is sulfur, and these
gases come up in a dry condition. I do not believe there is any water to
speak of in connection with them, except that necessary to alter the lime-
stone cap into gypsum. But these fault planes, created by the expanding
force, have been the determining cause of the domes, and the gradual
increase of the size of the plug of the salt domes is due to the cumulative
effect of volatile matter coming up through the cracks.

R. VAN A. MILLS,* Washington, D. C. (written discussionf). Mr.
Matteson not only contributes new and valuable data, resulting from
his investigations, but he attacks the problem on the basis of a multiple
hypothesis. By recognizing the grain as well as the chaff in several hypo-
theses and by applying such parts of these hypotheses as accord with the
facts thus far established, he has adopted the most promising method of
attacking the salt dome problem. 58

* Petroleum Technologist, Bureau of Mines.

t By permission of Director of Bureau of Mines.

68 R. Van A. Mills: Discussion on Oil-field Brines. See page 281.

330 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

That we are in no position to restrict ourselves to any one of the
theories previously advanced is recognized from several facts. The
presence of deep-seated salt beds in the Gulf coastal region from which
intrusive masses of salt might originate has never been established; the
evidence presented by Mr. Matteson, so far as it goes, is rather against
the presence of such beds. Again, there has been no systematic geo-
chemical study of the domal materials or associated waters, gases, and
oils, to determine their relationships together with the geochemical proc-
esses that have probably been operative in the dome building. Strange
to say, the only published results of a systematic investigation of this
kind come from the Appalachian region 59 where there are no salt
domes.

We agree that there has been intrusion by salt but we know neither
the origin of the salt nor the causes for the intrusion. Our theories
upon these phenomena constitute little more than working hypotheses
through which to attack the problem. Accepting this view, real progress
must come through systematic and laborious investigation rather than
by the easy and alluring road of speculation.

Advocates of the theory of primary intrusion of the salt masses have
endeavored to substantiate that idea by inadequate data and also by elimi-
nating all theories upon the deposition of salt from solution. They have
also attributed undue importance to the so-called flowage lines in the
salt masses; first, because the lines may be caused by secondary intrusion,
and second, because the lines may be of depositional origin. Such lines
commonly appear in specimens of the mineral salts deposited through
the agency of water in oil and gas wells. The lines are especially com-
mon in deposits of sodium chloride. Laboratory experiments indicate
that lines of this kind in masses of salt deposited from solution may be
largely, or wholly, of depositional origin. Irregular bands or lines in
the salt and gypsum deposits of southwestern Virginia are attributed
to secondary depositional phenomena by Stose. 60 Conditions in that lo-
cality apparently preclude any probability that the masses of salt and
gypsum attained their present positions and irregularly banded char-
acteristics through intrusion.

To what extent the growth of crystals may have contributed toward
the intrusion of the salt and uplifting of superencumbent strata in the
Gulf coastal region is problematic. It is recognized that enormous
forces are exerted in the growth of concretions and that certain failures
of concrete are caused by the forces of crystallization, but data upon the

* 9 R. Van A. Mills and Roger C. Wells: Evaporation and Concentration of Waters
Associated with Petroleum and Natural Gas. U. S. Geol. Survey Bull. 693 (1919).

60 George W. Stose: Geology of the Salt and Gypsum Deposits of Southwestern
Virginia. Virginia Geol. Survey Bull. 7 (1913), 70-71.

DISCUSSION 331

forces exerted through the crystallization of salt are meager. Rogers 61
cited data indicating that such forces would be inadequate to cause the
intrusion of the salt with the consequent uplifting of superencumbent
beds. He did not however, show that such forces were inoperative.
They have undoubtedly played their part. In laboratory experiments
upon the cementation of sands and the exclusion of water from oil wells
by plugging the interstices of the sands through chemical precipitation,
numerous instances of the displacement of sand by crystalline growths
have been observed. The crystaline precipitates formed masses that
displaced the loose sands. In these experiments, repeated failures of
the glass fronts of the apparatus were caused by the expansive effects
of the crystallization of chlorides, sulfates, carbonates, and silicates.

Recognizing that in the light of the meager information now available,
the effects attributed to the forces of growing crystals by Harris 62 con-
stitute a weakness in his theory, but also recognizing that the intrusion
of salt from one cause or another has played a major role in the dome
building, it is logical for Mr. Matteson to postulate intrusion through the
agency of dynamic forces acting from without the salt cores themselves.
The hypothesis of secondary intrusion, together with that of geochemical
origin of the cap rocks, constitute valuable working hypotheses for future
investigations.

Where so much has to be taken for granted and so much more has
yet to be learned through deep drilling, accompanied by systematic in-
vestigation, it is not to be assumed that Mr. Matteson has presented the
ultimate explanation for the origin of the Gulf coastal domes. We
must, however, recognize that his method of attacking the problem is
an important step toward the ultimate solution.

W. G. MATTESON (author's reply to discussion). The director of the
U. S. Geological Survey recently assigned M. I. Goldman to the Gulf
Coast province for the purpose of making a thorough study of the pres-
ence, variation in composition, physical character, and so forth of the
cap rock of the coastal plain salt domes.

Mr. E. W. Shaw says that "we have great need for more detailed
investigation concerning individual salt domes;" yet much of the specified
information he desires has been obtained. Unfortunately, however, such
data have not been gathered within one cover, for this would require a
monograph that only special organizations like the Survey have the
facilities to produce. As Messrs. Shaw and Mills state, an extensive
geochemical investigation of the coastal plain domes is needed, yet such

61 G. Sherburne Rogers: Intrusive Origin of Gulf Coast Salt Domes. Econ. Geol.
(1918) 13, 447-485.

"Gilbert D. Harris: Rock Salt in Louisiana. Louisiana Geol. Survey Bull 7
(1907).

332 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

an investigation is not without its difficulties. To be of greatest value,
it should be as extensive as outlined by Mr. Shaw, but this would require
several years of field work, considerable expense, and probably constant
change in the personnel of the investigators. Indeed, it is doubtful if
some of the information can be obtained. An examination, last 3 r ear, of
a proved dome required several months of persistent effort. The dome
had never produced, yet twenty wells had demonstrated its character
and some of these wells had excellent oil showings. In preparing the
map, it was necessary to find the drillers and then have them locate, in
the dense underbrush, the abandoned wells. Six months were required
to secure, from varied scattered sources, the logs of these twenty wells.
Some of the large companies that had drilled on the dome had no logs, so
that information could be obtained only by finding some outside person
who was interested in the tests at the time. If only the present producing
domes were thoroughly investigated geochemically, much new and valu-
able information would certainly be procured. In this connection, it is
to be earnestly hoped that the U. S. Geological Survey will increase the
scope of its present activity in the Gulf Coast region by having Messrs.
Mills and Wells continue their researches, which have been so fruitful
in the Appalachian province.

It is unfortunate that Mr. Shaw did not accompany his statements
respecting the quantity of gas necessary to cause vast salt deposition
through evaporation with adequate data and an outline of the method
by which he arrived at such conclusions, as his assertion is debatable.
Records show that the Yagua formation, of Eocene age, has yielded many
billions cubic feet of gas in the Gulf Coast region and has an estimated
possible potential production even more vast. Yet this is only one for-
mation of several that are gas bearing. Mills and Wells 63 call specific
attention to the fact that relatively small quantities of gas were capable
of causing deposition of several tons of salt in 24 hr. hi certain wells in the
Appalachian province. The statement that " when gas evaporates salt
water and deposits salt, the salt closes the pores and the process is self-
inhibiting," is merely speculation on Mr. Shaw's part. The only pub-
lished data relating to this phase are those of Mills and Wells 64 , and
apparently they find nothing to warrant the conclusions of Mr. Shaw.

The author was much surprised that Mr. DeGolyer should select the
Palestine salt dome in Anderson County, Texas, as an example of up-
thrust similar to that observed in European occurrences and, on this
basis, question the reliability of the writer's conclusions. The writer
made a thorough investigation, a few years ago, of the Palestine dome and

R. Van A. Mills and R. C. Wells: Evaporation and Concentration of Waters
Associated with Petroleum and Natural Gas. U. S. Geol. Survey Bull. 693.
64 W. G. Matteson: Op. cit., 3.

DISCUSSION 333

the Keechi dome, several miles to the northeast. The Austin Chalk and
overlying formations of Upper Cretaceous age are here found at the sur-
face entirely surrounded by the Wilcox formation, of Lower Eocene age.
There is no question that faulting has occurred, yet the evidence shows
the Wilcox to be tilted at angles of 30 to 40 and sloping from the center
of the dome on all sides. Likewise,the Wilcox is the next younger over-
lying formation of the geologic series in this specific area, the Midway
being absent. In few instances is the evidence of uplift (and not up-
thrust) accompanied by faulting and followed by erosion more positive
than here, this erosion revealing the presence of the immediately under-
lying Cretaceous formations. Few experienced Gulf Coast investigators
will agree with Mr. DeGolyer that these occurrences in Texas and North
Louisiana are real upthrusts of older formations into younger and es-
pecially of the nature and extent to justify their classification with the
European occurrences, where formations have been completely sheared
from their parent beds and upthrust many thousands of feet into much
younger horizons, which horizons in no way show the deformations
characteristic of the older rocks. While the presence of the Austin Chalk
at the surface at the Palestine and Keechi domes seemed to indicate a
local uplift of 3000 to 4000 ft., with the information available at that time,
recent data point to the Sabine uplift being much more extensive than
commonly supposed while the influence of the Balcones fault must also
be considered. It is quite probable, therefore, that the Cretaceous
formations here are not so deep lying as supposed and that the amount of
uplift will necessarily have to be modified.

The negative character of the results obtained by Phelan in his
analyses of bedded salt and salt-dome deposits and brines does not justify
any positive conclusions tending to disprove the writer 's statements.
While potassium salts may not have been characteristic of the bedded
deposits analyzed by Phelan, it is generally agreed that extensive bedded
deposits are often so characterized by such salts along with anhydrite.
Van der Gracht 65 and Kennedy 66 have admitted the difficulty of assigning
an exactly similar mode of origin to both the European and the American
salt domes, due to the general absence of potassium salts in the latter
instance, and the opinion of these authorities cannot be lightly disre-
garded. The potassium content of Humble and Sour Lake, mentioned
by DeGolyer, is very slight and might be due to several factors. Such
occurrences are of little value in the present discussion.

The writer finds no basis to justify Mr. DeGolyer 's conclusion that the
1000 logs examined in the present instance are of no value since they

66 W. A. I. M. von Waterschoot van der Gracht: Salt Domes of Northwestern
Europe. Southwestern Assn. Pet. Geol., Bull 1 (1917).
66 Personal interview.

334 SECONDARY INTRUSIVE ORIGIN OF GULF COASTAL PLAIN SALT DOMES

represent wells that have not penetrated below Tertiary horizons. These
logs, selected with extraordinary care, include a series of wells penetrating
varying formations from the lower Pennsylvanian to the Recent, yet
in not a single instance has the presence of bedded salt deposits been
detected in the Pennsylvanian, Cretaceous, or Tertiary. DeGolyer
says "the deepest wells in the Gulf Coast that have penetrated the domes
have not gone below the salt of the stock" but Kennedy 67 records a well
that passed completely through the salt into the underlying formations.
DeGolyer asks, "what theory will explain the tremendous upthrust by
which blocks of sediments, % to 1 mi. in diameter, are thrust upwards
4000 ft. to perhaps greater distances?" This question of uplift and not
upthrust is logically explained on pages 317 to 319 and the explanation
herein offered accords strictly with all facts. It is quite evident, however,
that the primary intrusive origin that Mr. DeGolyer is attempting to
substantiate will in no way adequately answer his question, for there is
absolutely no evidence of the action of orogenic forces of sufficient in-
tensity in the Gulf Coast region to push salt masses and accompanying
sediments upwards through thousands of feet of overly ing materials.
Moreover, why should we not find Cretaceous and older formations
overlying the salt in the domes along the Gulf Coast proper, or at least
fragmentary evidence of the same, if there is any merit in Mr. DeGolyer 's
contention that "if the primary intrusive theory is correct, the salt domes
had their origin in folded and faulted pre-Cretaceous rocks upon which
our Cretaceous and more recent rocks lie unconformably as a masking
mantle and that the salt stocks themselves were forced upwards into this
more recent mantle?"

In concluding the discussion, it might not be remiss to utter a word
of caution against the tendency to speculate without sufficient basis of
fact. The Gulf Coast salt domes offer a most alluring field in this respect
and the temptation has been too great for some of our most able authori-
ties to resist. After all, a theory is only a suitable working hypothesis
conforming to reason and observed conditions. As Mr. Mills says about
the problems of these domes, " real progress must come through system-
atic and laborious investigation rather than by the easy and alluring road
of speculation."

67 William Kennedy: Coastal Salt Domes. Southwestern Assn. Pet. Geol., Bull.
1, and personal interview.

APPLICATION OF LAW OF EQUAL EXPECTATIONS 335

Application of Law of Equal Expectations to Oil Production

in California*

BY CARL H. BEALJ AND E. D. NOLAN, t WASHINGTON, D. C.

(Chicago Meeting, September, 1919)

IN February, 1918, the conclusion was published by Lewis and Beal
"that wells of equal output on the average will produce equal amounts
of oil in the future, regardless of the ages of the wells." This conclusion
was based upon the study of data collected principally in Oklahoma and
was not known at that time to be true for other oil fields. An abundance
of statistical proof was later collected by the senior author of the present
paper, which showed that the conclusion was undoubtedly well founded
and that it applied to other fields as well. Accordingly, it was later
restated 2 as the "law of equal expectations" as follows: "If two wells
under similar conditions produce equal amounts during any given year,
the amounts they will produce thereafter, on the average, will be approxi-
mately equal, regardless of their relative ages."

Although only scanty data from the California oil fields were avail-
able at the time this publication was prepared, sufficient information was
analyzed upon which to base the insert on Fig. 80, which showed beyond
a doubt that the law held at least for a part of the Midway oil field in
California. Recently the authors have collected more complete data
in California, and it is the purpose of this paper to explain the method
used in demonstrating the truth of the law and, in addition, to give
several methods by which curves constructed in accordance with this
law can be used in a practical way with ease and accuracy.

THE FAMILY CUKVE

The law of equal expectations means that each individual of a group of
wells producing under similar conditions will decline along approximately
the same type of curve, the rapidity of decline varying with the output

* Published by permission of the Director, U. S. Bureau of Mines.

t Petroleum Technologist, U. S. Bureau of Mines.

$ Consulting Petroleum Engineer, U. S. Bureau of Mines.

1 Some New Methods of Estimating the Future Production of Oil Wells. Trans.
(1918) 59, 492.

2 Carl H. Beal: The Decline and Ultimate Production of Oil Wells with Notes on
the Valuation of Oil Properties. U. S. Bureau of Mines Bull. 177 (1919) 36.

336 APPLICATION OP LAW OF EQUAL EXPECTATIONS

of the well. For instance, if the first year's production of a well is very
large, its decline will be much more rapid than that of a well having a
smaller output. Furthermore, the second well will produce oil at the
same rate as the first well after the latter has declined to the same out-
put as the second. Inasmuch as the wells in a group, under similar con-
ditions, produce oil along a certain curve, if this curve can be made up
from decline records of wells of different size, we are able to forecast with
accuracy the decline of normal wells of different size in that area. Such
curves have been built up for different fields in California. They have
been called "family" curves for lack of a better name and because the
decline of wells of different output will follow the same curve.

The use of the family curve is not claimed to be original in the present
paper, as its possibilities were given by Lewis and Beal, 3 and one method
of preparing such a curve and its advantages were later briefly given by
Beal. 4 The particular method of building up the family curve, however,
is unique, and the various methods of using the curve for estimating the
life and future production of wells are new.

CONSTBUCTION OF FAMILY CuBVE

In preparing family curves for other oil fields, it has usually been
necessary to use the production records of tracts, for in most fields the
output of all wells on a tract is gaged in the same tank. The use of such
records has some advantages and some disadvantages. If the records
of individual wells are used, there will be smaller chance of the entrance
of such complex factors as the undue maintenance of production by the
bringing in of new wells on a tract. In the oil fields of California the
production records of individual wells are usually available, and the fol-
lowing curves are based entirely on such records.

Fig. 1 shows a family curve based on the production records of wells
in a California oil field. Briefly, the preparation of such a curve con-
sists of, first, choosing the records of all normal wells such as those
unaffected by redrilling, cleaning out, deepening, water encroachment,
etc.; second, plotting the yearly decline of the largest well A and joining
the points showing the production per year by straight lines; and, finally,
taking successively smaller wells and plotting the decline of each well,
the initial or first year's point being located on the production curve of the
largest well at the proper point, and subsequent points at spaces to the
right representing years. For instance, in Fig. 1, the points marked A
represent the decline of the largest well, those marked B represent the

Trans. (1918) 69, 512, Fig. 9.

U. S. Bureau of Mines Bull. 177 (1919) 198.

CARL H. BEAL AND E. D. NOLAN

337

decline of the second largest well, and points C, D, E, F, G, and H the
declines of the smaller wells. The initial point, or the first year's
production, of well B is located on the curve of well A at a distance of
90,000 bbl. (the first year's production) above the horizontal axis. This
procedure is repeated for the smaller wells.

After the declines of two or three wells have been plotted the average
line can be drawn by determining the numerical average of points within
adjoining vertical segments of the cross-section paper and drawing the
curve through the average points. From this time on, the decline of the
smaller walls may be begun on the average curve. For instance, in Fig.
1, after the records of wells A and B were plotted, the heavy average line
was drawn to point X and the first year's production of wells C, D, and E

23456789
Time Interval, One Space = One Year
( Regardless of Starting Point )

FIG. 1. SHOWING METHOD USED IN CONSTRUCTING A FAMILY CURVE FROM PRODUCTION

RECORDS OF INDIVIDUAL FIELDS.

were plotted on the curve. The process of gradually extending the family
curve and plotting on it the initial year's production of smaller wells is
continued until all the data are plotted. Rarely will a case be found where
the plotting of more than three or four wells is necessary to determine
the beginning of the average curve. The greatest difficulty is usually
experienced in determining the proper rate of curvature of the decline
curve when it begins to flatten out. This part of the curve usually
represents the exhaustion of the high gas pressure, which is closely as-
sociated with the rate of expulsion of oil from the well. After part of
the gas pressure is released, the curve representing the decline of prac-
tically any well, unless changed by some mechanical accident, trends
only slightly downward at a rate decidedly less than its previous rate of
decline.

VOL. LTV. 22.

338 APPLICATION OF LAW OF EQUAL EXPECTATIONS

It should be noted that the entire length of the average, or family
curve, as shown by the heavy line in Fig. 1, is the result of the plotting of
past production. Sufficient data are usually available so that the curve
can be carried even to the point representing minimum economic pro-
duction, so that the necessity of projecting the curve to represent pro-
duction in the future is obviated. The family curve in this case is based
absolutely on actual performance. The objection to some curves is
the necessity of projecting them, the projection in many cases varying with
the person who makes it. This is not true, however, with the family
curve, especially when the records of several wells representing different
outputs are available.

In a new field, such as the Montebello field, it might be found ad-
vantageous to construct a curve with a monthly time interval as the
horizontal scale. Then with wells but a few months old, a family curve
may be prepared with but little difficulty.

Another method 5 of preparing a family curve is to divide the produc-
tion records into classes representing different productivity. The yearly
output of all wells in the highest class (those that made 110,000 to 120,000
bbl. the first year) is averaged; then the yearly output of the next highest
class (those that made 100,000 to 110,000 bbl. the first year) is
averaged, and the average points plotted and so on until all the aver-
ages are obtained.

USE OF FAMILY CURVE

Because wells of different size decline along the same type curve,
the work of making estimates of future production is greatly simplified.
The life of the average well can also be quickly determined and the limits
of decline may be shown graphically. Furthermore, the future yearly
production of a well of any output may be read directly from the average
family curve.

FUTURE PRODUCTION CURVES

In Fig. 2, curve A, above the family curve B, was determined by
adding the future production of wells of different output as shown by
the family curve and then plotting these future production estimates
vertically above the point on the family curve representing the first
year's production of a well. For instance, assume a point on the family
curve, representing 21,000 bbl. to be the first year's production of a
well of that output. The second year's production will be one year
to the right, the third year's production two years to the right, etc.,
to the point of minimum economic production. These estimated annual
productions, with the exception of the first year, as shown on the family

6 Carl H. Deal: U. S. Bureau of Mines BuU. 177 (1919) 198, and Fig. 80.

CARL H. BEAL AND E. D. NOLAN

339

curve, are added together and plotted vertically above the point on the
family curve representing the first year's production, and a curve A drawn
through the points. In the present instance, the yearly production, as
represented by the family curve, is as follows:

YEAR

2
3

4
5

PRODUCTION,
BARRELS

21,000

15,000

11,500

9,000

7,000

YEAR
6

7
8
9

Total

PRODUCTION,
BARRELS

5,500

4,000

2,000

1,000

76,000

; leu.wu
g

*^ 14.0 000

120,000
o

3
o 1 00 000

"g 80,000

1
a 60 000

(3
5

i2 /in ooo

r<-

"IH on ri/in

! * *

^D 0/ ,

C8 ^O.OUO

S o

** j

L2 ~~1

i ~~i

j s

!<*

i
J

^ii^<

7 (

Jurve^

>x^0^

***

--^

**
d \

"
1

Remaining Life of Well, (Years )

FIG. 2. AVERAGE FUTURE PRODUCTION AND " FAMILY " CURVES OF A CALIFORNIA

OIL FIELD.

The average ultimate production of the well will be 76,000 bbl.,
and the future 55,000 bbl. (76,000-21,000). The future production,
55,000 bbl., is plotted vertically above the point on the family curve
representing 21,000 bbl. Because of the law of equal expectations,
the production of 21,000 bbl. could represent the most recent years'
production if desired; that is, suppose the well during 1918, its third
year, produced 21,000 bbl. Then if the well is an average well, it will
produce 55,000 bbl. from 1919 to 1926, inclusive, and it produced 30,000
and 45,000 bbl. during 1917 and 1916, respectively.

By the use of curve A, the future production of a well at any period
of its life may be determined by selecting the production for the last

340 APPLICATION OP LAW OP EQUAL EXPECTATIONS

year. Find this amount on the left margin and trace the line to the
right to a point where it intersects the family curve, follow the vertical
line through this point upward to its intersection with the future produc-
tion curve, thence to the left margin of the figure. The reading is the future
production of the well selected. For example, take a well that made
20,000 bbl. during the first year, follow the horizontal line to the right
to its intersection with the family curve, thence upward to its inter-
section with the future production curve and thence to the left margin
where 53,000 bbl. is indicated as the average future production of a well
of that output. The estimate would have been correct if the production
of 20,000 bbl. represented the most recent year's production instead of
the first year's production.

DETERMINING AVERAGE LIFE OF WELLS OF DIFFERENT SIZE

In the lower margin of Fig. 2 will be found figures that decrease to the
right. These figures represent the remaining average life of wells and
are determined by counting the years of remaining life for wells of differ-
ent output, as shown by the family curve. For instance, the remaining
life of the well that made 20,000 bbl. during the first year, by reading
downward on the vertical line passing through the point on the family
curve representing 20,000 bbl., is found to be 8 years. From this curve,
it is evident that the lives of oil wells vary directly as the volume of
production, for the larger the production, the longer the remaining life.

ULTIMATE PRODUCTION CURVES

If desired, the future production may be added to the last year's pro-
duction, which will give the ultimate production direct. These statistics
may be plotted for wells of different size and curves thus constructed.
Both this and the average future production curves may be plotted if
desired, although the ultimate production may readily be obtained by
first determining the future production and adding to it the past year's
production.

ANOTHER METHOD OF SHOWING FUTURE PRODUCTION CURVE

The curve representing future production may be expressed as an
average appraisal curve if desired. The appraisal curve was named by
Lewis and Beal, 6 and consists of showing the relation between the first
year's production of a well and its ultimate production. The suggestion
was made that additional curves showing the actual future could be
plotted by subtracting from the ultimate production the past year's

Trans. (1918) 69, 492.

CARL H. BEAL AND E. D. NOLAN

341

production. The future production curve, as arrived at by the family
curve, may be expressed in the same way; that is, the past year's pro-
duction may be used as the abscissa and the future production may be
shown as the ordinate. In this way, the curve begins a distance to the
right of the lower left-hand corner, which represents the minimum eco-
nomic production to which the average well in a district can be pumped,
and rises gradually to the right, having the same form as appraisal curves.
There is no particular advantage in this form of curve over curve A,
Fig. 2, which likewise represents future production directly.

ERRATIC WELLS

In any field, certain wells will be found having a decline wholly differ-
ent from that of the family curve of that group; these usually are con-

120.000

100,000

3
PQ

^ 80,000
u

Jj 60,000

5
g

o 40,000

v X^4

v >H

S
\ ,'

20,000

-Sr^-^

T -BT
~t>-..

BS "

-S?

B, B

LI 1

1 C

Remaining Life of Well, (Years)

FIG. 3. PRODUCTION OF ERRATIC WELLS PLOTTED ON "FAMILY" CURVE TO SHOW
THAT SUCH WELLS USUALLY DECLINE ALONG SOME PART OF THE CURVE AFTER ERRATIC
PERIOD ENDS; RECORDS INDICATED BY A AND B ARE WELLS IN CALIFORNIA FIELD.

sidered abnormal wells. The causes of these wells may be divided
roughly into three classes geological, accidental, and lack of histories
of wells. Geological causes may be either a very thick series of oil sands
with varying gas pressures or the comparatively sudden invasion of edge
water. In certain small districts, such as the area in Sec. 27 f T. 19 S.,
R. 15 E. in the Coalinga field, or that near Fellows in the North Midway
field, the thickness of oil-bearing series is from 500 to 70Q ft. (152.4 to
213.3 m.). Wells drilled through this thick series of alternating oil sands
and shales often show an increasing production for 2 or 3 years after
inception. After having reached their maximum, however, their de-
cline follows the family curve. The probable explanation of this increase
is as follows: Such wells penetrate a number of rich oil sands, but under

342 APPLICATION OF LAW OF EQUAL EXPECTATIONS

varying gas pressures. When first brought in only those sands with the
higher gas pressures are able to produce but time permits a lessening and
readjusting of the pressures and all sands are able to contribute to the
well's production. Curve A, Fig. 3, shows the production of a well of
this type and its relation to the family curve. Wells producing from a
sand suddenly invaded by water may show an increase in production just
prior to the appearance of the water, but almost invariably show a
rapid decline and a sudden end.

Accidental causes of erratic wells might also be called mechanical
causes. The "oil string" may collapse, shutting off its production, or
a redrilling job may be a failure, causing the abrupt ending of the well's
life. In the loose unconsolidated sands of the California fields, shale
may cave in, shutting off the perforations. These accidents usually
cause a sharp break in the decline of the well and a consequent dropping
away from the family curve. After this initial break, its decline through
the remainder of its life usually follows some other part of the family
curve. The decline indicated by B, Fig. 3, is of such a well.

Another class of erratic wells that often cause trouble are those that
have been deepened. When a well is deepened into lower sands or is
redrilled, with a consequent opening of new sands, or possibly shutting
off other oil sands, it must be treated as a new well, and accordingly a
new part of the family curve selected as its decline curve.

Wells varying from the family curve sufficiently to be termed erratic
wells are rare, certainly less than 10 per cent, of the total wells in the Cali-
fornia fields. The divergence in most erratic wells takes place during
the first 2 or 3 years of the life of the well. From that time on, the out-
put of the well follows some part of the family curve.

ESTIMATING FUTURE PRODUCTION OF WELLS ABOVE AND BELOW THE

AVERAGE

Most wells in a field will follow the family curve with fair exactness.
Some will trend slightly above it, follow it for a year or so, and finally
fall below. One is usually safe, however, in making estimates of the
future production, if he assumes the well to be an average well; he is
unwise, however, if he makes no effort to determine the amount a well
is above or below the average, for if it deviates far from the average the
estimate may and should be modified accordingly. Fortunately, as
most estimates of future production are made by using the last year's
production, the curve tends to correct itself by automatically shifting
the point on the family curve at which the estimate is made to the right
or left, according to whether the curve is below or above the average.
This may be more clearly shown by taking an example. Suppose well
A, Fig. 3, has produced 2 years, as shown by A and A\\ the estimate of

CARL H. BEAL AND E. D. NOLAN 343

future production is made by applying the last year's production (indi-
cated by AI) to the family curve, thus shifting the point AI to the left
to where a horizontal line through it intersects the family curve. As
subsequent production from this particular well has proved (see points
A' 2, A ' 3 and A' 4 ), the estimate of future production would have been
slightly above the average curve.

Another example will serve to show the method by which the esti-
mates of future production of wells below the average will tend to correct
themselves. Suppose well B, Fig. 3, has produced 2 years (B and BI),
an estimate of its future production will be made from point B\ on the
family curve. Subsequent production would indicate that the well pro-
duced along a curve (B' z , B'$ and J5' 4 ) almost coincident with the family
curve. If estimates are made yearly, they become closer and closer even
though the well may produce along a curve considerably above or below
the average.

FAMILY CURVE APPLIED TO TRACT OR PROPERTIES PRODUCTION

Where the individual well records are lacking or where the average
well production is quite small, it may be either necessary or convenient
to construct a family curve for a group of tracts rather than for a group
of individual wells. Such curves when constructed from a number of
properties and applied to properties that are sufficiently drilled are quite
accurate.

VALUE OP FAMILY CURVE

The greatest advantage of the family curve is the fact that it is based
entirely on history; it usually has no projections and it is not difficult to
prepare. Furthermore, its advantage over the appraisal curve is that it
can be prepared with less data. In fact, the statistics representing
the decline of a dozen wells might suffice for the preparation of a curve,
the decline of which represents the decline of wells of different size in an
area where conditions affecting production are practically equivalent.
The accuracy of the curve, however, is increased in direct proportion
to the number of records used in its preparation.

Another advantage over appraisal curves is that the future produc-
tion of a well from its first year can be estimated more readily when the
decline of the well is above or below the average. Owing to the fact that
the last year's production is used and that erratic wells after their abrupt
change follow a portion of the family curve, the curve reduces error to a
small amount, and tends to correct errors due to its own limitations.
The simplicity and completeness of the curve are the principal arguments
in its favor. One may read direct the future production of a well, its
probable life in years and its probable production in any year in the
future.

344 ESSENTIAL FACTORS IN VALUATION OF OIL PROPERTIES

Essential Factors in Valuation of Oil Properties*

BY CARL H. SEAL,! M. A., SAN FRANCISCO, CALIF.

(Chicago Meeting, September, 1919)

THE most important factors that should be given consideration in
the valuation of oil lands are: (1) the amount of oil the property will pro-
duce; (2) the amount of money this oil will bring (based upon the future
prices of oil); (3) development and production costs; (4) the rate of in-
terest on the investment; (5) the retirement or amortization of invested
capital; and (6) the salvage or " scrap " value of the equipment when the
property is exhausted. These factors are of varying importance and
some of them may not enter all valuation problems, but most of them
should be given consideration in any valuation even though only a rough
estimate of the value of the property is desired.

The value of a property may be changed over night by the completion
of important test wells, by the sudden water flooding, or by a change in
the price of oil. The best a petroleum engineer can give is the value of
the property under the conditions existing at the time the appraisal is
made with a fair forecast of future action of the wells and of the price of oil.

Our experience in the scientific valuation of oil lands is not broad and
there is very little published information on the subject; it, therefore,
becomes necessary in studying such problems to form comparisons with
the factors involved in the valuation of mines the closest parallel.
One of the reasons for the lack of substantial progress in oil-land valua-
tion methods has been the necessity of making an estimate of the
future production of the oil property to be valued. Oil men and ac-
countants have not generally conceded that such estimates could be
made with any degree of accuracy. It has been shown, however, in
several recent publications that with certain data available reasonably close
estimates can be made. The accuracy of an appraisal depends chiefly
on the accuracy of the estimates of future production and of the future
price of oil. The accuracy of the former is sometimes necessarily based
on geological inferences. Geology is not an exact science and geological
data in connection with oil production cannot always be mathematically
evaluated.

* Published by permission of Director, U. S. Bureau of Mines,
t Petroleum Technologist, U. S. Bureau of Mines.

CARL H. BBAL 345

FUTURE OIL OR EXPECTATION

In considering the factor of future oil, two related questions must be
answered: How much oil will the property produce? At what rate will
the oil be produced? If we can determine the future annual production
of an oil property, we may easily determine the total future production
by addition, so we will consider only the question of rate of future oil
production.

A satisfactory answer to this question is the keynote to the whole
valuation; for, although our work, has, by no means, been completed
after the question has been disposed of, the work of determining the value
of the property is greatly simplified, for on the yearly output of oil depends
the yearly gross income. From the gross income the annual net return
is computed, each year's return being considered in the light of a profit
available at a future date. The present value of these deferred profits
is then determined by discounting them at a rate of interest compatible
with the risk involved.

No uniform yearly revenue can usually be expected from an oil prop-
erty, for the annual output, and thus the annual income, depends on
the rate of production. Only under exceptional conditions can a steady
oil production be maintained for long unless the property is old and pro-
duction well settled. The future annual oil output hinges on the rapidity
with which new wells are drilled and on the rate of production of the
individual wells which, with very few exceptions, always declines.

Rate at Which Oil Will Be Obtained. The rate of production of the wells
will affect not only the rate of output of the old wells, but will regulate
that of the wells to be drilled. Furthermore, the decline in the initial
output must be considered; the longer the development of the proved
acreage is deferred, the less will be its ultimate production, for, under
usual conditions, the wells on the drilled acreage cause a decrease in gas
pressure over the undrilled acreage, which results in decreased initial
production of the wells eventually drilled there. The rate at which oil
wells will produce is the resultant of many complex factors, which will
not be discussed here. For more information on this subject, the reader
is referred to a bulletin by the author. 1

The most trustworthy method of determining the rate of production
of the wells of a group is to prepare a production curve that will give the
average yearly output of wells of different initial yearly output. It is
necessary to determine this for wells of different initial production, be-
cause wells of different output decline in production at different rates
other factors being equal.

1 Carl H. Beal: Decline and Ultimate Production of Oil Wells with Notes on the
Valuation of Oil Properties. U. S. Bureau of Mines Butt. 177 (1919).

346 ESSENTIAL FACTORS IN VALUATION OF OIL PROPERTIES

Drilling -Program. The rate of the production of the property depends
not only on the rate at which the individual wells will produce oil but also
on the rapidity with which new wells are added to the producing list;
this depends on the drilling program. The valuation should not be
attempted until a drilling program is decided upon. But before a drill-
ing program can be determined, it is necessary to know the amount of
land that certainly will support commercially productive wells ; trust-
worthy estimates of future oil production can be made only for the drilled
acreage and for the undrilled proved acreage. Only such land furnishes
a concrete basis of value, for the annual production of oil can be esti-
mated; other land has a speculative value that varies with the uncertainty
of obtaining oil in commercial quantities. These tracts, if included,
should be valued separately and on a different basis.

Although there is no case exactly parallel in metal mining, the metal-
mining engineer refuses to commit himself on the value of a prospective
mine. The petroleum engineer may determine the magnitude of the
risk and compute mathematically the probability of obtaining oil on a
tract of land; but the author is inclined to agree, in a measure, with
Rickard 2 that "the doctrine of probabilities has been stultified too
often to allow of its being stated as a scientific thesis. "

In valuing the proved oil land, the engineer should compute the
value of the output of the property based on a drilling program that
will bring the maximum return in profits to the investor. It is true
that a variation in the drilling program sometimes will greatly reduce
the profits eventually gained from a property, but there can be only
one maximum value and this is the one to be determined.

CLASSIFICATION OF LAND TO BE VALUED

Before the future annual production can be estimated, it is necessary
to classify the land to be valued, to determine the amount of acreage
that will support new wells. For this purpose the land is first divided
into drilled and undrilled. These two classes of acreage must be valued
separately.

Estimating the future production of the old wells usually is not
difficult, if production curves are available. Our greatest difficulty
lies in making estimates of the probable future production of the proved
undrilled acreage. Here we must be guided by underground geologic
conditions and by what the new wells probably will produce by comparing
the conditions under which they are to produce with the conditions
under which the nearby old wells are producing. The undrilled oil

1 T. A. Rickard: Valuation of Metal Mines. International Engineering Congress,
1915.

CARL H. BEAL 347

land may usually be divided into the following four general classes:
Proved acreage, probable acreage, prospective acreage, and commercially
non-productive acreage. Some engineers use much more detailed
classifications. These, the writer believes incompatible with the un-
certainty of underground conditions. The following definitions are
advanced tentatively:

Proved acreage should include that in which drilling involves practi-
cally no risk. The following definition is proposed, which has been
modified from that given by R. P. McLaughlin. 3 " Proved oil land is
that which has been shown, by finished wells supplemented by geologic
data, to be such that other wells drilled thereon are practically certain to
be commercial producers."

Probable oil land includes those areas generally adjacent to produc-
ing oil and gas wells where the existence of oil is not proved, but where
geologic evidence indicates a good chance of obtaining oil in commercial
quantities.

Prospective oil land includes those areas usually not adjacent to
producing oil and gas wells, where the existence of oil is not proved, but
where geologic data justifies drilling a test well. Land in this class is
distinguished from the probable oil land by the greater uncertainty of
obtaining oil owing, usually, to its location some distance from producing
oil and gas wells.

Commercially non-productive oil land is that on which commercially
productive wells cannot be drilled at present. The existence of oil
under the areas of this class may be proved, probable, or prospective.

Exceptions undoubtedly will be found in every class. For instance,
under some conditions, a person may feel warranted to place land in the
probable class when it is favorably located geologically, even though it
is several miles from producing wells, for the reason that the occurrence
of oil and gas with relation to certain geologic structures in that region
may be so certain as to make the chance of not obtaining some oil very
small. Furthermore, the classification of land may change rapidly,
owing to the drilling of new wells, damage by water, or change in price.
For example, an area that may be rated as commercially non-productive
may become commercially productive and proved with an increase in
the price of oil.

FUTURE PRICE OF OIL

The accuracy of any valuation depends on the price that is to be
received for the oil, for on it depends the net profit per barrel of oil
marketed. A small variation in the price of oil may mean the difference

3 R. P. McLaughlin: Petroleum Industry of California. California State Mining
Bureau Butt. 69 (1914) 13.

348 ESSENTIAL FACTORS IN VALUATION OF OIL PROPERTIES

between gain or loss. In fact, since the working out of new and more
trustworthy methods for more accurately estimating future oil produc-
tion, the estimation of the future price has become one of the most uncer-
tain elements to be contended with in oil land valuation.

The engineer, to make sound predictions as to the probable price of
oil, even during the immediate future, must possess a broad knowledge
of the petroleum situation as regards supply and demand. Either
prices will be allowed to adjust themselves in accordance with the law
of supply and demand, or they will be manipulated by monopolies or
controlled by the Federal Government. If manipulation or government
control exists, or if there is a strong probability of their coming into
existence, the engineer should be guided accordingly. Otherwise, the
question of price must be answered solely by the domestic and foreign
oil situation. The past range of prices has often been great, but the
future probably will never see such low prices of oil. The market is
now more stable because the demand for the commodities made of
petroleum is greater and new oil fields are much more scarce and more
costly to develop.

The reason for the great demand for oil is primarily because of the
great demand for one of its products gasoline. The great demand for
gasoline is created by the phenomenal development of the internal-
combustion engine. This development is, probably, by no means, com-
pleted. The adoption of oil as fuel by the great navies of the world and
the development and adoption of the Diesel engine have greatly increased
the demand for the heavier products of petroleum. Very likely the
future demand for oil and its products will not decrease.

The upward limit of prices is set by the cost of importing oil and
the- cost of developing a supply of oil from oil shales, of which there are
immense deposits in this country. By considering the status of the in-
dustry at the present time and these two limiting factors, the engineer
should be able to make reasonably sound estimates of the price of oil
for the next few years. Some engineers find it advisable to use the present
prices as a basis of estimating the value of the property or to determine
the value of the property at several different prices of oil, and thus allow
the investor to select the one that, in his judgment, will best meet future
conditions.

COST OF PRODUCTION AND DEVELOPMENT

In determining the future net receipts from each barrel of oil, the
cost of producing the oil must be subtracted from the gross income or
selling price. For the purpose of estimating future production costs,
including drilling charges, tankage, and, in fact, every charge that con-
tributes to the final total cost of production, the appraiser should refer to
trustworthy statistics and should be able to interpret these statistics in

CARL H. BEAL 349

terms of probable future conditions. This, again, requires not only a
broad knowledge of the oil industry but also detailed knowledge of costs
in the locality where the property is situated.

INTEREST ON INVESTMENT

The proper rate of interest to be received from an investment must
be such that capital will be attracted to the enterprise. If the risk
attached to the investment is great, the rate of interest on the money
invested must be high or investors cannot be found. The returns from oil
investments are always speculative to some degree, so the interest
demanded is usually high. If there is no risk, the investor can afford to
invest his money at the same rate as if he put it in the savings bank at 4
per cent.

The basis of value in oil. lands is net income. The net income for
each future year of the productive lif e of the oil property must be estimated
and these future values compared with their real values at the present
moment by reducing them to present value at a given rate of interest.
This is discount and is the reverse of compound interest, the factor used
in the reduction of future values to present values being called the dis-
count factor, which is a very important element in oil-land valuation.
By the reverse of discount, or compound interest, the future value of a
present income may be determined.

Present value of a future income may be defined as that sum which,
when placed at interest at a stated per cent., will equal the income at the
date when it is to be realized. Thus, the longer the deferment of an
income the less it is worth at the present time, for which reason one can
afford to pay more for income to be obtained from the oil from a well
drilled now than for the same well drilled a year hence, providing the price
of oil remains constant and equal amounts of oil are produced. Further-
more, the longer drilling is postponed the less the net proceeds from the
wells are worth to a prospective purchaser at the present time. Other
things being equal a property should be drilled as quickly as possible, if
the maximum income is to be derived from it. This may not be best
from the standpoint of the public, and, if generally practiced by oil
producers, would eventually work to their advantage.

The interest required on the investment must be high because risk
is attached to the venture. Some engineers consider that the discount
used in reducing future income to present value, however, should not
be compounded for the reason that to compound a certain present sum
to determine its future value means the first year to determine the
interest on the principal and thereafter to compute yearly the interest on
the principal and accumulated interest earnings. The rate used is a
high rate because the capital, or principal, is being risked. This rate

350 ESSENTIAL FACTORS IN VALUATION OF OIL PROPERTIES

should not be applied to the accumulated interest earnings, however,
because these are not risked capital. They are earnings and should
be considered as such.

The computed maximum value of the property may be considerably
less than what actually could be paid for the property for as the returns
in the investment are realized they may be reinvested in gilt-edged
securities at an accumulative rate of interest.

AMORTIZATION OF INVESTMENT

In investing in an exhaustible resource, the investor expects not
only the return of a certain interest on the investment, but also the
return of the principal by the time the resource is exhausted. This is
called amortization, or retirement of capital, and may be effected by a
sinking fund into which annual contributions are made. The sinking
fund may be placed at interest, so that the sum of the annual contri-
butions may not be required to equal the total original capital. Although
sinking funds may not be established, some attempt must be made to
return capital uniformly and justly, where it is possible to estimate the
amount of oil recoverable and the hazard of the investment is not too
great to make such calculations useless.

A method often practiced by oil companies to determine the rate of
retiring the capital invested in both physical property and in the re-
source is called the "settled production method," and consists of apply-
ing a unit value per barrel of settled daily production. The value of
the property at any time is the daily production mutiplied by the unit
value. The difference in the value determined at any two periods is the
depreciation or appreciation according to whether the value has gone
down or up.

A modification of this method for the purpose of determining the
depletion deduction in connection with the computing of taxable income,
is called the "reduction in flow method." The method has been author-
ized by the Treasury Department, but obviously is unfair, when it is
remembered that the basis of the method depends on a reduction in the
output of an oil property from the existing wells only. No depletion is
allowed and, therefore, no capital is retired unless production is decreas-
ing. If production decreases 5 per cent, during the taxable year, 5 per
cent, of the capital invested is retired. During the next year, if the
decrease is 10 per cent., that percentage of the unretired capital is
" written off." As a general rule, the output of an oil property increases
for a few months, at least, while drilling of new wells is in progress, and
in some fields, production may increase for several years. Still, by use
of this method no capital can be retired until the production of the tract
begins to decrease. Production of oil means depletion of its recoverable

CARL H. BEAL 351

content and every barrel of oil taken from a property exhausts it just
that much, and brings it just that much nearer the end of its life. To
retire no capital while production is largest and then when production
begins to decline, to retire large amounts against a decreasing income
not only is inequitable to the oil operator but places the whole enterprise
in jeopardy by deferring the amortization to a period when the field is
rapidly approaching exhaustion and too late to cover the return of
capital.

The producer has made a definite investment in each barrel of recover-
able oil. If he can estimate the amount of recoverable oil, he can easily
determine the cost per barrel. For every barrel of oil produced, he
should retire an amount of capital equal to the original investment in
that barrel of oil. This is called the "unit cost method," by which a
fixed charge per barrel of oil produced, based on quantity, is assessed.
It is sound in principle, not difficult of application, and has been adopted
by the Treasury Department in the determination of the depletion
deduction in connection with the administration of the income and excess-
profits tax laws. This undoubtedly is the fairest and most equitable
method of amortizing an investment in a mineral property. The method
is suggested in several publications on mine accounting, 4 so has the added
weight of precedence.

The basis of this method is to determine the total capital invested in
the oil and then divide the estimated recoverable oil into the capital
invested ; the result is the unit cost. For instance, if the sum of $1,000,000
is invested in the oil under a property, estimated to produce ulti-
mately 10,000,000 barrels of oil, the unit cost per barrel is 10 c. The
producer has paid this sum for each barrel of oil under the property.
If he sells each barrel of oil for $1.50, his net income for each barrel
will be determined by deducting all charges from $1.50. Suppose all
charges, excepting unit cost, amount to 40 c. per barrel, his net income
is, therefore, $1.

Estimates of future production may be revised each year and a new
"unit cost" obtained by dividing the unretired capital by the remaining
recoverable oil. The amount of capital to retire during that year on
account of depletion will be the unit cost multiplied by the production.

Many oil companies have adopted this system because by its use they
are enabled not only to determine the depletion deduction equitably and
justly, but also because they are enabled to retire the capital investment
at the same rate at which the oil is produced. The only unknown factor
in the determination of unit cost is the amount of recoverable oil, and

4 F. Hobart in "The Economics of Mining," by T. A. Rickard and others, 223,
1905.

352 ESSENTIAL FACTORS IN VALUATION OP OIL PROPERTIES

this can be estimated with a reasonable degree of certainty by the use of
methods outlined by Lewis 6 and the author. 6

Depreciation refers to the wear and tear on physical property and
capital invested in it must be retired in addition to the capital invested
in the exhaustible resource. The methods of retiring such capital will
not be discussed in this paper. The amount retired should be equal to
the capital invested minus the salvage or "scrap" value of the equipment.

SALVAGE VALUE OF EQUIPMENT

When the oil is exhausted, a certain amount of physical property will
be on hand. The investment in this physical property should have been
completely amortized, with no investment remaining except that which
can be realized from the disposal of the equipment. This sum is called
the salvage, or "scrap/ 7 value of the equipment. Ordinarily this "junk"
value is not great at the exhaustion of the oil. Furthermore, the pro-
ceeds derived from the sale of the "junk" must be discounted to the
time of the valuation at a certain rate of interest. Usually the property
will have a life of more than 20 years, and the present value of the junk,
even at a comparatively low rate of interest, is rather small when com-
pared with other sources of income that must be present before the invest-
ment is a good one. Occasionally, the expenses in connection with the
abandonment of the property, such as properly plugging the wells, will
cost as much or more than the present value of the junk, so that this
item in oil-land valuation is ordinarily not important.

6 J. O. Lewis and Carl H. Beal: Some New Methods for Estimating the Future
Production of Oil Wells. Trans. (1918) 69, 492.
U. S. Bureau of Mines Bull. 177.

APPRAISAL OP OIL PROPERTIES 353

Appraisal of Oil Properties

BY EARL OLIVER,* PONG A CITY, OKLA.

(New York Meeting, February, 1920)

THE term oil property, in this discussion, includes any type of ease-
ment or grant under which petroleum might be produced; it ranges from
the mere right to drill on undeveloped wildcat acreage up to a fully
developed oil property. The values of an oil property, as thus defined,
vary widely according to the use for which it is intended, whether it is
from the viewpoint of the speculator, the fraudulent stock promoter,
the refiner and pipe-line owner, or the oil producer.

The market value of a property is usually a combination of some
two or more of these influences, and occasionally a combination of all
of them, but we prefer to treat each viewpoint as distinct from the others,
allowing the reader to make his own combination in such proportions
as his inclination and property seem to require. This paper will treat
the subject from the viewpoint of the oil producer. However, the other
influences have such bearing on the cost of property to the producer
and on the price he might obtain by its sale as to warrant brief discussion
of them.

Speculation, particularly lease speculation, is a parasitic growth on
the oil industry, healthy enough, but of no economic value. The class
of property usually dealt in for this purpose is the undeveloped lease.
Its speculative value may have some relation to its probable productive
value, but most frequently this value is the product of temporary
excitement due to local development. The lease speculator, seeking out
the trend of development or securing early information regarding a pro-
posed test or a new discovery, immediately secures leases whose market
value will be increased when the existence of such development becomes
more widely known. His profits are purely unearned increment.
Not proposing to spend money in exploration, he can afford to compete
in purchase with the operator, who, in addition to bonus paid,. must
spend large sums in testing out his own acreage and that of the nearby
speculator as well. It has a tendency to compel unduly high bonuses.
The so-called "checker-board" system of leasing wildcat acreage by the
larger companies is on the same principle of attempting to secure the

* Member Executive Staff, Marland Refining Co.

VOL. Lxv. 23.

354 APPRAISAL OF OIL PROPERTIES

benefit of money expended by others in testing, but most of them remove
the obnoxious holdup feature by contributing toward such testing by
others in proportion to the benefit they themselves secure.

Fraudulent stock promotion, as contrasted with lease speculation, is
an unhealthy disreputable growth and justifies mention only that
attention may be called to the burden it places upon the oil industry.
The value of an oil property for this purpose has no real relation to its
productive value, the property being selected for its adaptability to a
fantastic tale of fabulous earnings to draw money from people with
small savings. Consequently, the promoter pays for leases suitable to
his purpose prices entirely out of proportion to their probable economic
value. Such prices, however, immediately influence owners of surround-
ing unleased areas when dealing with the legitimate operator.

The lease speculator and fraudulent-stock promoter, while entirely
dissimilar in their standards of ethics and respectability, have, therefore,
this in common they tend to place on prospective oil-producing areas,
before these get into the hands of the oil operator, values that have little
relation to their economic value. The impossibility of determining the
exact economic value, the knowledge that other men are paying like prices,
and the optimistic spirit of the operator generally lead him to meet
these fictitious values and pay prices for undeveloped leases, especially
in the vicinity of a new discovery, entirely out of proportion to their
chances of being profitably productive.

Prior to 1888, the American oil industry was operated in two distinct
divisions : first, that of the producer, who brought the oil to the surface ;
and, second, that of the refiner, who purchased the crude oil at the well
and carried it through all remaining phases, including, in some instances,
its sale to the consumer. However, about the date mentioned, would-be
competitors of the then dominant refining interest, recognizing the neces-
sity of owning and controlling producing properties as an insurance
against disturbance of their crude supply, began to acquire oil-pro-
ducing properties. The dominant refining interest quickly adopted the
same practice, until now the greater percentage of production is owned
and controlled as a necessary adjunct to the refining and transporting
branches of the industry. New pools, when opened, have diverse owner-
ship but eventually gravitate, to a great extent, into the character of
control mentioned. Thus, while to the oil producer, as such, an oil
property has value only to the extent of the margin of profit between
the cost of the oil as produced and his receipts for it as sold in its crude
state, to the refiner and transporter it has a double value one of which
is identical with that of the producer, while the second is that it stabilizes
and makes secure his more important business of transporting and refin-
ing, provided his producing properties are so situated as to make his

EARL OLIVER 355

production available for his facilities. The value of the property for the
latter purpose is frequently of much greater importance than for the
former.

VALUE OF OIL PROPERTY TO THE PRODUCER

The value of an oil property to a producer as such (stripped of its
speculative feature) is simple in principle and is nothing more nor less
than the present worth of the aggregate margin of profit between the
expenditures for producing, saving and disposing of the oil in its crude
state and the price received for the same. To ascertain such value is
a simple matter in accounting of balancing expenditures against re-
ceipts and introducing interest charges. It differs little from the average
bookkeeper's problems except that it is reversed. The bookkeeper
balances expenditures against receipts on business that is past; the oil-
property appraiser balances expenditures against receipts on business of
the future. To his bookkeeping ability he must, therefore, add the
ability to see into the future and underground as well.

His principal difficulties are to determine the number of barrels of
oil the particular property will produce and the price per barrel he will
receive. He has several other factors to consider, such as the cost of de-
veloping, and of maintenance and operating, but these are easily disposed
of if he is able to accurately forecast the first two named.

Until within very recent times there has been no one well-established,
widely used, generally accepted method of determining the probable
future production of an oil property. Scientists have evolved general
theories as to the laws controlling the accumulation of petroleum that
have much merit; in a large way, they are helpful. It must, however, be
confessed that in their early application, or rather misapplication, to
individual small tracts for valuation purposes the results obtained by them
have been disappointing. These theories introduce too many assump-
tions to make the appraisals safe as a basis upon which to invest large
sums of money. Consequently, an experienced oil producer, who had
the details of a few properties stored in his mind for the purpose of com-
parison, was more successful in judging values of oil properties.

But the average oil producer, whose real business is operating the
properties he controls, has no inclination nor time to collect data that
would give him a wider vision than his own experience furnishes him,
and is handicapped to that extent. These two men, the scientific theo-
rist and the experienced oil producer, represent the two types of appraisers
that have been known to the oil industry for many years. The difference
between them might be better understood by stating that the early
petroleum engineer, in purchasing a race horse, would have investigated
carefully the history of the dam and sire for several generations back,

356 APPRAISAL OF OIL PROPERTIES

ascertained what food and treatment the dam had prior to the foaling,
would have given a hasty glance at the horse itself and concluded, that
in view of the record of its progenitors and the early influence brought
to bear upon it, it should be able to do a mile in 2 min. flat, and, accord-
ingly, purchase it on that basis. Whereas, the producer, purchasing
the same horse, would send it around the track, time it, and buy it on the
speed shown, in ignorance of inherited and prenatal influences.

There is now being evolved a new type of petroleum engineer. He
knows the theories of the scientist, but he demands that they shall be
measured up with actual results. He knows what percentage of struc-
tures in a given locality have been found productive or barren upon being
tested. He knows, from compiled data, where oil accumulates. He
calculates oil content per acre by counting barrels actually produced from
similar areas already exhausted. He measures the numerous scientific
theories with actual results. His business is the collection of complete
data from innumerable properties so that he may know the habits of
petroleum, instead of assuming for it certain habits in keeping with his
ideas of what they should be. This new type of petroleum engineer is
expected to develop methods of determining the probable productiveness
of certain areas with much greater accuracy than the methods now avail-
able will permit. However, until such methods and data are available,
it is necessary to use the older general principles.

METHOD OF APPRAISING OIL PROPERTY

The property is first divided into developed and undeveloped por-
tions. The developed portion is then subdivided into " settled" and
"flush" productions, provided the old and new wells are not so inter-
mingled as to make this impracticable. For both classes it is desirable
to have production figures extending back month by month to the com-
pletion of the wells. Should these figures not be available, they should
at least run back one or two years, if the wells are old enough.
There will, of course, in so far as it is available, be a complete history of
each well and full data regarding it, including, among other things, date
of completion, initial and present productions, thickness and depth of
sands, casing record, gas and water production, vacuum application,
etc. One purpose is to ascertain whether the composite production is
made up of comparatively uniform wells, and whether the production
figures as shown month by month represent the regular and natural rate
of decline, or whether some unusual condition might have changed the
past production from the natural rate. Should there be such condition,
its influence is given such consideration as it appears to warrant, and it is
eliminated, if possible, from the figures.

On the "settled" production figures, a curve is then constructed
covering the entire past life of the property in so far as such figures are

EARL OLIVER 357

available. While properties of the same age differ greatly in their rates
of decline, each property, throughout its entire history, is characterized
by the same rate of decline; i.e., if during the first part of its history it
shows a rapid rate as compared with other properties of like production
per well and age, it will have a rapid rate up to the point of exhaustion.
After the flush production is off, provided the wells are not unusually
large, the rate of decline is so uniform as to make possible, for all practical
purposes, the use of some definite percentage each year from the previous
year. Thus, some properties will decline at the average rate of 40 per
cent, each year from the previous year, while other properties will de-
cline only at the average rate of 15 per cent. Consequently, when on
settled production the figures are available, by constructing a curve
running back several years, it is comparatively easy and safe to project
the curve to the point of exhaustion. Of course, it must be seen that
some extraneous influence does not cause the decline to deviate from its
natural rate.

For the appraisal of individual settled properties, where something
more reliable than mere generalities is desired, a general production
curve should not be used; instead the curve of the property itself
should be projected. The writer has before him curves of several
Bartlesville sand properties 6 to 8 years old in substantially the same
district, and which would ordinarily be considered of the same type and
subject to the same decline curve. Yet they range from 15 per cent,
annual decline on some properties to 40 per cent, on others, which means
that the first named, although having no more present daily production
than the latter, will produce three times as much as the latter before
exhaustion.

Every producing property is a type unto itself and where reliable ap-
praisal is desired no property can be thrown into any general class at so
much per barrel. Each property has characteristics that place it above or
below the average and as stated on settled production, located apart
from new wells, it is desirable that its own production curve be projected.

With flush production, however, this cannot be done since there will
not have elapsed sufficient time to indicate a rate of decline. Reliance
upon general decline curves cannot be avoided, but care should be
taken to select a curve compiled from properties as similar in type
as it is possible to secure. As a check, data compiled from similar prop-
erties as to yield per acre-foot is helpful for " flush productions," although
of too general nature to be of assistance in appraising "settled" produc-
tion. Briefly, therefore, for "settled" production the curve of the prop-
erty examined should be projected while for "flush" production the use
of a general decline curve compiled from similar properties is permissible.

The undeveloped portion of a property should be viewed from an
entirely different angle. This will range from so-called rank "wildcat"

358 APPRAISAL OF OIL PROPERTIES

acreage up to that which is sufficiently surrounded by production as to
be substantially proved. It is rare, however, that any undrilled acreage
will be so thoroughly proved as to justify a method of appraisal that
will include assumption of a certain number of locations with an assumed
initial production per well and with application thereto of a decline curve.
Theoretically such method appears satisfactory but it does not work out
well in practice. However conservative the appraiser attempts to be
such method of appraising generally leads to overvaluation. It is poor
practice. Such a method starts with the assumption that the undrilled
acreage will be productive and then attempts to call to mind all factors
of uncertainty for which discount should be made but some of these will
be missed and the property be, thereby, given a higher rating as to cer-
tainty of production than, as a rule, it justifies.

The basic assumption on undrilled acreage should be the reverse of
the above; i.e., that it is barren, and then such factors should be assembled
as will tend to take it out of that class. Perhaps this distinction has not
been made clear and it has reference only to the state of mind of the
appraiser toward the property, but this tendency toward optimism re-
garding the probable productiveness of acreage has caused much more
money to be spent in the attempt to produce oil than the industry has
paid back in the aggregate to the producer. By the very nature of the
industry there must be great individual gains and losses but the industry
as a whole should pay its own way; and the fact that it does not in the
aggregate do so should be more widely recognized and values adjusted
accordingly.

It is in this field of undeveloped acreage that the work of the petrol-
eum engineer is in most need of extension. Comprehensive data showing
the percentage of seemingly favorable structure that has proved profitably
productive, the conformity of subsurface to surface structure in given
districts, the percentage of production seemingly off structure, the per-
sistence of sands, the yield per acre-foot, and thorough study of the
accumulation of oil as it is actually found to exist rather than a preconceived
theory of how it should accumulate, together with a more widely spread
knowledge of the results will be helpful to the industry and place unde-
veloped acreage on a proper footing. Such factors together with many
others must be taken into consideration by him who would appraise
undeveloped acreage with any degree of safety. This investigation must,
however, be made with the cold calculating analysis of the engineer
who looks only at facts, rather than by the scientist whose province is
farther afield.

A factor in the appraisal of oil properties of almost equal importance
to the amount of oil secured is the price to be received for the oil. Re-
gardless of the views sometimes asserted, the market price of crude oil
and the usual fluctuations are influenced by the law of supply and

EARL OLIVER 359

demand. In attempting to forecast the price that might reasonably
be expected for the oil output of a property it is, therefore, necessary to
assemble and consider the factors that will influence supply and demand.
This is a large field; there is no intention to say that an actual price can
be forecast, but that the market trend can be reasonably foreseen over
at least the next thereafter succeeding 2 or 3 years. However, this
phase of the subject must be left for future discussion.

Having determined upon extent and rate of production that might
reasonably be expected from a property and the probable trend of the
market price, there then enter the cost of development and maintenance
and the consideration that should be given the possibility of increasing
the amount of oil to be produced by the application of different methods.
This, again, is an uncertain field and if the property is fully drilled such
possibility frequently no more than offsets the dangers unseen. The
equipment that is needed for the permanent operation of the property
should be given no credit unless the property is relatively near the point
of abandonment.

FACTORS INFLUENCING VALUATION OF OIL PROPERTY

A few of the questions that must be considered by one who would
eliminate as much as possible the factors of uncertainty in the purchase
of properties, together with the character of information that would be
helpful are here given, although the outline is by no means complete.

I. Plans of Purchaser

1. General scope and business of company

2. Purpose for which property is needed

3. Amount of oil needed

4. Amount of money available to secure it

II. Probable Oil Market Trend

1. Production: (a) World's past and present production, in detail by coun-

tries and districts, and by whom controlled, in each instance giving
wells completed and producing. (6) World's probable future production
by countries and districts, and by whom controlled.

2. Consumption: (a) World's past and present consumption, showing dis-

tribution by countries and districts and distribution as to use. (6) The
world's probable future needs as to countries and as to uses.

3. Prices: (a) Of crude oil. (6) Of refined products, (c) Margin of profits.

(d) Prices to which crude petroleum might go before other products be-
come competitor.

4. Graphic charts of prices, production, and consumption

5. Possible substitutes and probable influence of same

6. General consideration of factors that might influence price, and survey of

the entire field of market trend

360 APPRAISAL OF OIL PROPERTIES

III. Selection of Regions for Exploitation

1. Geographical location

2. Geology: (a) General petroleum possibilities. (6) Laws controlling local

accumulations, (c) Degree of conformity of production to structure.
(d) Persistency, thickness, and characteristics of petroleum-producing
strata, (e) Comprehensive data showing actual petroleum extracted
per acre-foot from all types of producing strata. (/) Rate of decline of
various types of producing properties, with described conditions, (g)
Water conditions.

3. Development: (a) Past history. (6) Maps marked up to date.

4. Oil: (a) Quality, (b) Amount produced by periods, (c) Market price of

same by periods, (d) To whom sold.

5. Relative cost to operate: (a) Depth and cost of wells. (6) Method of

operation, (c) Proximity to supplies and markets.

6. Relation to transportation systems

7. Relation to company's plans and its existing properties

8. Ownership compilations: (a) Production figures and comprehensive owner-

ship data on producing properties. (6) Comprehensive ownership data
on non-producing lands.

9. Records of sales of both producing and non-producing properties to indi-
cate prevailing prices

IV. Selection of Properties. This section deals with especially selected properties
that might be worthy of consideration as contrasted with regions dealt with in
section III and therefore goes much more into detail in each case.

1. Geographical and legal description

2. Geology: (a) Surface, (b) Underground, (c) Persistence, thickness and

characteristics of possible producing strata, (d) Water conditions, (e)
Application to this property of laws of accumulation peculiar to region.
(/) Data showing production per acre-foot from similar already
exhausted properties, (g) Data showing probable rate of decline de-
duced from past history of this property, also from similar already
exhausted properties.

3. Development: (a) History. (6) Well records, (c) Maps marked up to

date, including adjoining properties.

4. Oil: (a) Quality. (6) Amount by periods produced from beginning of

development, (c) Market price, (d) Possible markets, (e) Probable
amount to be produced, (f) Probable rate of decline.

5. Relative cost to operate: (a) Depth and cost of wells, (b) Production

expense, (c) Method of operation, (d) Equipment, (e) Proximity to
supplies, labor, and markets.

6. Relation to transportation systems

7. Relation to company's plans and its existing properties

8. Records of sales of similar properties to indicate prevailing prices

V. Terms of Lease

1. Rate of royalty 3. Development requirements

2. Term to run 4. Unusual conditions

VI. Taxation questions and general governmental conditions and safeguards
VII. Conditions of title

DISCUSSION 361

DISCUSSION

CARL H. BEAL, San Francisco (written discussion). I heartily
endorse the statement that the petroleum engineer should look at oil
properties, if possible, from the viewpoint of the practical operator.
Too much appraising has been based on theory and not enough on facts.
If the facts were not available, this process of appraising might be con-
doned; but the files of practically every oil company contain consider-
able data of importance that should be studied in connection with oil
production.

Mr. Oliver has brought out one important fact; that is, the influence
of the speculator and the fraudulent stock promoter on the selling price
of leases. These men greatly increase the amounts that must be paid
for proved and wildcat land. Incidentally, this fact makes difficult the
adoption, by the Treasury Department, of sales values of actual trans-
actions as a method of limiting the values placed on developed and partly
developed oil land. Some time ago this method was suggested as one
that would be used as a possible limitation by the Department in check-
ing valuations made for the purpose of determining the depletion deduc-
tion. High market values nearly always prevail in a new field where the
excitement is running high. Ranger a year ago is a good example. The
actual amounts of oil that could be obtained from some of the partly
developed leases would lack much of measuring up to the average sales
values of surrounding properties. Market values much higher than
intrinsic values indicate a speculative period, whereas intrinsic values in
excess of market values indicate a period of stagnation, when oil-property
transactions are rare. The market values may fluctuate rapidly because
of new discoveries, but the actual value reposing in the oil does not
change, except as the factors influencing such values change; for instance,
an increased demand, lower or higher drilling costs, etc. An average of
exchange values over a long period of years would equal the actual value
of the properties, for the prices paid during periods of excitement and
periods of depression will result in an average that fairly represents
actual value.

Mr. Oliver separates the developed from the undeveloped parts of the
property and then the "settled" from the " flush" production. It often
has been very difficult for me to separate the flush and settled pro-
ductions, for there seems to be no particular line of separation between
them. In some places the wells may be called settled after 6 months, in
others after 1 year, whereas other wells may be called settled from the
very beginning. The age of a well when its production is settled varies
with the initial production and the conditions under which the oil is
produced. A well drilled in the Lima-Indiana field coming in at 10 or
15 bbl. a day very likely will have but a short period of flush production;

362 APPRAISAL OP OIL PROPERTIES

whereas a 5000-bbl. well in California may be irregular in its production
for several months, or even 2 or 3 years. Flush production is a relative
term of use in describing production of individual properties, but diffi-
cult to define.

The future production of wells still in their youth may be estimated
from data showing the relation of the production of a well the first day
or month to its output during the first year. Most production curves
used in estimating the future production of oil properties are based on
the rate of decline of wells, which produce different amounts the first
year. If the relationship between the production of the first day or the
first month and the production of the first year can be determined, the
estimate of the future production of new wells may be much more accu-
rately made than by the method suggested by Mr. Oliver. I found by
studying many records in Oklahoma that the average well in the fields
east of Gushing would produce daily, in the first year, about 25 per cent,
of its initial daily production. In other words, if the initial production of
a well were 100 bbl., its first year's production would be about 9000 bbl.;
although this ratio changes for wells of different initial output, it may
be used in roughly estimating the amount a new well would make the
first year. In California, I find this ratio to be much different; for
instance, in some fields a 100-bbl. well will make between 50 and 75 bbl.
daily the first year.

The statement that where individual properties are being appraised
a curve of the property itself should be projected, for estimating the future
production of that property, cannot be too strongly emphasized. Some
of us are prone to apply average curves, but the curves of the property
itself are very much more trustworthy and simpler to use. The details
of preparing such a curve are simple. The annual production should be
obtained, if possible, for the life of the property, and the average number
of wells producing divided into this annual production. The result-
ing amounts are the annual production per well of the property. In
almost any property where drilling has been carried on at a normal rate
the peak of production of the property will occur only a few years after
the first well has been drilled; often it will occur in the first or second year.
From that time on, regardless of the rate at which the property is drilled,
the annual production per well decreases. This curve, projected into the
future, will show the estimated annual production per well. The only
remaining step in the problem is to estimate the number of wells that will
be producing each year in the future. After these annual amounts have
been determined, they are multiplied by the estimated annual production
per well; the product is the estimated future annual production.

Possibly one reason that this method has not been used more is
because some persons believe that, as all wells in the field have not been
drilled, the daily production per well will be upheld by the yield of new

DISCUSSION 363

wells. This objection is not valid, especially if the production per well
in the district has begun to decline on account of interference. After a
field or property has attained a certain age, the decline in the daily pro-
duction per well remains practically unchanged, regardless of the number
of new wells drilled. It is necessary, however, that the wells shall be
drilled close enough to be affected by drainage. In a field where the pro-
ductive sand is lenticular, or made up of several disconnected lenses, or
if the wells are widely spaced, this method cannot always be used.

Referring to Mr. Oliver's statement that yield per acre -foot should
be obtained, I have not been able to obtain sufficient data to prove
that such statistics are of any value. Production per acre, I believe,
is very much preferred, for the reason that it is practically impossible
for anyone to determine the portion of a sand that produces the
oil. The thickness is not measured accurately in the first place. Some
parts of the sand are more porous than others, and some parts produce
water. It is possible that the pressures in the various members of an oil
sand or zone may be different. The first production of a well may come
from two-thirds of the sand, until the pressure is reduced to that of other
members of the sand, and the next portion of the production may be
expelled from all parts of the sand. Statistics on production per acre
from a sand like the Bradford sand in northwestern Pennsylvania prob-
ably would be of some value, but most of the oil sands with which I am
acquainted are so irregular that statistics of production per acre-foot
cannot be compiled that are of any particular use.

The reference to the necessity of estimating future price of oil in
oil-land appraisals brings up one of the most difficult factors in valuations.
Although, as Mr. Oliver says,the market trend can be reasonably fore-
seen over at least the next 2 or 3 years, to forecast future price for several
years, as is necessary in oil-land appraisals, is not in accordance with the
exactitude that engineers desire in their profession. The fact remains,
however, that some estimate must be made, and the engineer is the man
who must make it. In making the estimate, it is necessary for him to
consider the economic side of the oil industry; a small variation in the
price of oil may mean the difference between gain or loss. In fact,
since the working out of new and more trustworthy methods for more
accurately estimating future oil production, the estimation of the future
price has become one of the most uncertain elements to be contended with.

R. H. JOHNSON, Pittsburgh, Pa. Stress on division of the flush
and settled periods is an unfortunate habit. It is far better for us
to think of the thing as a curve than to get this other impression.
Mr. Oliver takes a regular percentage decline for several years after
he says the well is settled; in the flush period we are not offered any
particular guidance. That is unfortunate. It is in the flush period

364 APPRAISAL OF OIL PROPERTIES

that a great many purchases are made; and the man who is trying to
find out the values of properties, the man who wishes the services of the
appraiser, is very much concerned with that period. If we think
of this whole thing as a curve and study the problem as a whole, we are
on a more healthful basis than this artificial distinction.

Mr. Oliver has exaggerated the period of time that one is safe in using
the same percentage of decline year to year. It is true that we approach
such a curve in the old age of the well, but Mr. Oliver starts too early
to assume that we can take a constant percentage of decline.

Mr. Oliver should have given some attention to the compound
discount factor in working out present worths. He says that the prices,
in the long run of exchange values, will average the productive value, that
is, the periods of inflation will cancel the periods of depreciation, so that
in the long run productive values must be the same as exchange values.
This is not correct. Except in periods of excitement, we generally make
a considerable allowance for risk. I never like to recommend the pur-
chase of a property at exactly what I think it is worth. I always feel that
we should recommend a liberal allowance for risk to a purchaser. To
be sure, there are inflated values, but they are recognizable. In fact, it
is not uncommon to find old operators who say that they buy on the
basis of paying out in four, or some other number of years. To be sure,
these men have not made a regular allowance for compound discount.
It is probably partly involved in this expression of theirs, although
they do not realize it, but it is also partly the fact that they wish to
allow an ample amount for risk. That should be the custom of all
buyers, with the possible exception of the one who has a large refinery
that must be kept going and who must protect himself from loss at other
points.

VARIATION IN DECLINE OP VARIOUS OIL POOLS

365

Variation in Decline Curves of Various Oil Pools

BY R os WELL H. JOHNSON, M. S., PITTSBURGH, PA.

(New York Meeting, February, 1920)

THE Manual of the Oil and Gas Industry, under the Revenue Act of
1918, published by the Treasury Department for the guidance of oil
companies in preparing their estimates of future recoverable oil for the
purpose of calculating depletion, gives the first large public collection of
comparative decline curves for the whole country. It is a matter of both
scientific and practical interest to so arrange these data that the pools can
be readily compared. There are certain difficulties in such a comparison,
however: (1) The economic limit varies from 50 to 2000 bbl. a year in
different pools taken. (2) Because of this variation in economic limit,
the range of data shown makes comparison possible only for wells of
intermediate size.

In order to be as inclusive as possible, I have taken as an expression
of the rate of decline the amount of oil produced in the period during
which a well drops from 3000 to 2000 bbl. a year. No period of
smaller production could be used because of the high economic limit in
California; and no period of larger production and yet include the small
well areas of the Appalachian. As it is, the Lima-Indiana wells are
excluded. In a few instances, curves were extrapolated to obtain the
reading, where the curve seemed regular enough to warrant it.

In general, the amount of oil, in barrels, produced while a well de-
clined from 3000 bbl. to 2000 bbl. a year is shown in Table 1.

TABLE 1. Production of Wells During Decline from 3000 to 2000

Barrels a Year

Field

Minimum
Barrels

Median
Barrels

Mean
Barrels

Maximum
Barrels

California

2,500

5,800

6,260

10,200

Gulf Coast (Saratoga only)

2,160

3930

5700

South Mid-Continent

1,700

2,700

2,666

3,600

Gulf Cretaceous

1,000

1,500

2,175

5600

Mid-Continent . . .

600

1 350

1 785

3400

Rocky Mountains

700

1,310

3,170

7,500

Appalachian

450

1,225

1,489

2.750

Illinois

410

1 288

1 285

2200

366 VARIATION IN DECLINE OF VARIOUS OIL POOLS

Amount of oil produced while well declined from 3000 to 2000 bbl. a year.

Appalachian Field

BARRELS

Big Injun sand, Roane Co., W. Va 2550

Gordon sand, Greene Co., Pa ' 2300

Berea sand, Lincoln Co., W. Va 1900

Gordon sand, Wetzel Co., W. Va 1850

Shinnston pool, Harrison Co., W. Va 1400

Clinton sand, Wayne and Hocking Co., Ohio 1300

Wayne Co., Ky 1150

Gore pool, Perry and Hocking Co., Ohio 1050

St. Mary's pool, Washington Co., Ohio 850

Dorseyville, Allegheny Co., Pa 500

Ragland, Ky 500

Irvine, Ky 450

Illinois Field

BARRELS

Dennison pool, Lawrence Co., Ill 2200

Siggins pool, Cumberland Co., Ill 2075

Robinson pool, Crawford Co., Ill 1550*

Carlyle & Sandoval pools, Clinton and Marion Co., 111. . . 1500*

Upper Lawrence Co., Ill 1500

Birds-Flatrock pool, Crawford Co., Ill 1425*

Pike Co., Ind 1150

Kirkwood pool, Lawrence Co., Ill 1150

Johnson pool, Clark Co., HI 1140*

Sullivan pool, Sullivan Co., Ind 700

Plymouth pool, McDonough Co., Ill 630

Westfield pool, Clark Co., Ill 410*

* Extrapolated.

Oklahoma-Kansas Field

BARRELS

Bird Creek-Skiatook district, Okla 3400

Glenn pool, Okla 3200

Okesa district, Okla 2850

Avant-Ramona district, Okla 2850

Cleveland district, Okla 2800

Bartlesville-Dewey district, Okla 2000

Okmulgee district, Okla 1800

Blackwell district, Okla 1500

Muskogee-Boynton district, Okla Ti <v 1350

Eldorado district, Kans.. .V - 1300

Augusta district, Kans 1200

Gushing district, Okla 1110

Nowata district, Okla - 1100

Garber pool, Okla 1100

Adair district, Okla 1000

Neodesha district, Kans 600

ROSWELL H. JOHNSON

367

South Mid-Continent Field

BARRELS

Burkburnett pool 3,600

Electra district 2,700

Healdton pool 1,700

Gulf Cretaceous Field

Corsicana pool 5,600

Mooringsport pool 2, 100

Marion Co., Tex 1,600

DeSota parish, La 1,400

Vivian pool, La 1,350

Red River district, La 1,000

Wyoming Field

Salt Creek pool 7,500

Grass Creek pool 1,310

Elk Basin pool 700

California Field

BARRELS

Kern River pool 10,200

McKittrick district. 10,000

Olinda district 10,000

Old Santa Maria pool 9,500

Fullerton-La Harba pool 9,000

Twenty Five Hill pool 9,300

Maricopa Flat pool 6,700

West Side Coalinga pool 6,000

Salt Lake pool 5,800

East Side Coalinga pool 5,500

Belridge pool fc 4,500

Lost Hills pool 4,000

Buena Vista Hills pool 4,000

Whittier district 3,900

West Coyote pool 3,500

Fellows-Midway district 3,000

Shields Canyon district, Ventura

Co 2,500

The Gulf Coast data are given with two different bases of reference,
so that all the districts are not mutually comparable. Those under
each head may, however, be compared. Amount of oil produced while
well declined from 3000 to 2000 bbl. a year: Saratoga Rio Bravo
normal spacing, 5700 bbl.; Saratoga town lot spacing, 2160 bbl.
Amount of oil produced while well declined from 500 to 300 bbl. a
month :

BARRELS

Batson 4780 Humble

Evangeline 4230 Vinton

Sour Lake . . 3075 Goose Creek .

BARRELS
1680
1530
1230

For the sake of finding how the Lima-Indiana pool ranks with other
small-well pools, Table 2, based on the oil produced while the wells
are declining from 500 to 100 bbl. a year, was prepared.

TABLE 2. Production of Wells During Decline from 500 to 100 Barrels

a Year

Field

Minimum
Barrels

Median
Barrels

Mean
Barrels

Maximum
Barrels

Appalachian . .

450

1700

1655

3150

Limfl.-TndiaTia .

965

1278

1315

1990

Illinois

400

1255

1171

2100

368 VARIATION IN DECLINE OF VARIOUS OIL POOLS

Amount of oil produced while well declined from 500 to 100 bbl. a
year in the various pools is as follows:

Appalachian Pool

BABBELB

Fifth sand, Pa 3150

Keener sand, Jasper Ridge pool, Monroe Co., Ohio 2850

Speechley sand, Pa 2800

Bradford sand, Pa * 2550

Floyd County, Ky 2050

Ragland, Ky 2000

Gordon sand, Allegheny Co., Pa 2000

Berea sand, Lincoln Co., W. Va '. 1800

Hundred foot sand 1750

Gordon sand, Greene Co., Pa 1700

Gordon sand, Wetzel Co., W. Va 1700

Berea sand, Jefferson Co., etc., Ohio 1600

Big Injun sand 1400

Keener sand, St. Mary's pool, Washington Co., Ohio 1100

Wayne Co., Ky 850

Shinnston, W. Va 600

Clinton sand, Perry and Hocking Co., Ohio 600

Irvine, Ky , 600

Dorseyville, Pa 450

Clinton sand, Hocking and Wayne Co., Ohio 450

Trenton Pool

BARRELS

Hancock Co., Ohio . 1990

Wood Co., Ohio 1410

Seneca Co., Ohio 1380

Adam Co., Ind 1300

Ottawa and Lima Co., Ohio 1255

Sandusky Co., Ohio 1230

Grant Co., Ind 990

Mercer Co., Ohio 965

Illinois Pool

BARRELS

Siggins pool, 111 2100

Robinson pool 1850

Johnson pool, 111 1780

Gibson Co., Ind 1425

Westfield pool, 111 1270

Birds-Flatrock pool 1240

Pike Co., Ind 835

Carlyle and Sandoval, 111 410

Plymouth pool, 111 400

Sullivan Co., Ind 400

Caution must be used in avoiding conclusions based on differences not
clearly in excess of probable error, yet the following conclusions seem to
be warranted from the differences which are large and consistent.

ROSWELL H. JOHNSON 369

1 The widespread impression of the much greater persistence of the
California field is fully borne out in general, yet a considerable variation
is shown.

2. The great importance of the thickness of pay is well borne out
by the great contrast, in Wyoming, between Salt Creek on the one
hand and Grass Creek and Elk Basin on the other.

3. The Gulf Cretaceous shows a great contrast between the persistent
Corsicana and much less persistent northern Louisiana fields.

4. The south Mid-Continent field shows an excellent persistence at
Electra, Burkburnett, and Healdton. The more recent close drilling in
Burkburnett and the inclusion of the Ranger, Desdemona and Caddo,
Texas, pools will cause this field to show less favorably in the future.

5. The three fields of oldest geological age all show poor persistence.
The hypothesis that this is characteristic of fields older than Devonian
is proposed. This should be expected theoretically, as there should be
an increased cementation in older beds, so that the low pressures in old
wells become impotent' to expel oil. The fields in question are the Lima-
Indiana of Ordovician age and the Clinton and Hoing sands (Plymouth
pool) of Silurian age.

6. The poor showing of the Appalachian fields, which are relatively
younger (Dorseyville and Shinnston), is probably due to the method
employed, which bases the future history of all wells on the performance
of the small wells in the early history of the pool. These small wells,
having in general a thinner pay, have a more rapid decline than the
typical wells after they have reached the same size.

7. The most interesting result is that the Appalachian is apparently
not more persistent than the Mid-Continent, as had been supposed, when
wells of the same size are compared. The long life of the Appalachian
wells is mainly the result of the lower economic limit. The Mid-Continent
wells will show a longer life as the price in that field rises and so puts
down the " economic limit " of the wells. This consideration is af avorable
one in the appraisal of Mid-Continent properties.

8. There is a great variation from pool to pool within the field. It
follows that the attempt to appraise a property by applying to it the
barrel-day price of a property in some other pool or sand or an aver-
age from many pools or sands is unwarranted where the data permit
an analytical appraisal.

9. Since the rate of decline is not constant, the barrel-day price
unit changes during the life of a property, therefore barrel-day prices
are not comparable except for properties of similar age and size as well
as the same pool.

VOL. LXV. 24.

370 VARIATION IN DECLINE OF VARIOUS OIL POOLS

DISCUSSION

M. L. REQUA, New York, N. Y. (written discussion). In paragraph
7 of his conclusions, the author states a fact, that is well known to many
people, but which I think, is overlooked by the general public; that is,
that the line of an oil field bears direct relation to the price of the product.
In other words, with every advance in the price per barrel there will be
more barrels made available in the form of oil that cannot be produced
except at high prices. There is a dead line, of course, beyond which no
production will take place. This dead line is well illustrated by the prac-
tice, in certain fields, of "flooding" with water and driving the oil to the
surrounding wells. When the surrounding wells begin to pump water,
the end has been reached, of course, regardless of price. Again, regard-
less of price, I think it entirely feasible to construct a decline curve to
the point of exhaustion. Whether the property will operate in the latter
years of this curve is dependent entirely on the price at which the product
can be sold.

CHESTER W. WASHBURNE, New York, N. Y. (written discussion).
Further explanation of Table 1 would be appreciated. It is not clear
how a well that declines from 3000 to 2000 bbl. a year could produce
less than 2000 bbl.; probably I do not understand just what the author's
figures represent. The comparisons in these tables and the resulting
conclusions are most useful in appraisal work. Most scientific investi-
gators, doubtless, already have reached Professor Johnson's seventh
conclusion : that Mid-Continent wells will show as long life as Ap-
palachian wells of equal size. Moreover, there is every reason to
expect a closer approach of price per barrel in the two fields, and an
increase in the "economic limit" of Mid-Continent wells. That region
is today the best part of the United States in which to buy oil lands on
current market prices of production.

CARL H. BEAL,* San Francisco, Calif, (written discussion). The
value of oil properties depends principally on the amount of oil they will
produce and the rate at which this oil is to be obtained. This is a self-
evident fact and requires no proof. Consequently, such studies as those
made by Mr. Johnson are of the greatest value and interest, for they
furnish a definite comparison of the rates at which wells in different
Gelds will give up their oil. Studies of this kind show the importance,
furthermore, of studying the effect of various factors influencing, and
controlling the amount of oil that may be obtained from an oil sand, and
the rate at which this oil will be given up.

Mr. Johnson's comparison of the rate at which oil is obtained in
different fields would be more illuminating and valuable if augmented

* Petroleum geologist and engineer.

DISCUSSION 371

with a similar comparison of the amounts that the different fields
produce per acre. Other factors being equal, the amount of oil that
may be produced by an acre of land depends on the initial production
of the wells drilled to this sand, and the rate at which the oil is produced,
for ultimate production, under such circumstances is a function of initial
production. These statistics may be obtained without great difficulty
from the same data used by Mr. Johnson in the preparation of his paper;
in fact, such a comparison could be made much more easily than the
one of the decline curves.

This study shows not only the necessity of more investigation along
this line, but the necessity of getting at the fundamental influences that
control production in different oil fields. Certainly the variation shown
by Mr. Johnson to exist can be laid only to the factors influencing pro-
duction, or the different conditions under which the oil is produced in
the oil fields of the United States. If all fields existed under the same
conditions originally and development and production were carried on
in the same manner, the decline curves would be identical. As they are
not identical, the conditions affecting the production of oil must be dif-
ferent, for development and production conditions are usually approxi-
mately the same in all fields.

As each decline curve possesses its particular shape because of the
composite results of the factors influencing oil production, it is essential
that we strive to learn the effect of these different factors on the decline
of oil wells, so that, with a few of the more important factors known, we
can predict with approximate accuracy the decline of the wells in a new
field. For instance, let it be assumed that the composite effect of all
the important factors influencing the rate of production in a certain field
is known, the thickness of the oil sand is not variable, the wells are spaced
a certain distance, and the depth is fairly uniform. By an analysis of
these data one can determine in what way almost any important factor
affects the ultimate production per acre, and the rate at which the oil is
obtained. If the influence of each production factor in the field can be
measured, the estimation of the possibilities of properties in other fields,
if one or more of the important production factors are similar, will be
greatly facilitated. The problem is to determine the individual influences
of the different factors. We already know that certain production fac-
tors have certain specific influences upon the output of wells; for instance,
large initial production will create a tendency toward a large ultimate
production, whereas a small initial production will create a tendency
toward a small ultimate production. Thick and thin sands react in the
same manner, respectively.

If the individual effect of these conditions, or production factors, can
be determined, there should be no great difficulty in estimating the gen-
eral tendency that will be followed by producing wells in new fields,

372 VARIATION IN DECLINE OP VARIOUS OIL POOLS

providing some of the more important factors are known. For instance,
take the new Ranger field in north Texas. More than a year ago it was
evident to anyone familiar with the influences of different production
factors that the wells of Ranger would have a rapid decline and
produce but small amounts per acre. In fact, the particular decline that
these wells would follow could have been forecast with fair certainty, for
the reason that the conditions in southeastern Ohio in certain localities
were practically equivalent. In the latter district, the high rock pressure,
probably due to the great depth, and the thin and rather porous sand
favored rapid decline and small ultimate production. Unquestionably,
if any new field were found to exist under approximately the same con-
ditions, we could expect approximately the same production rate. As
thick sands were not common in Ranger up to a year ago and as the depth
was approximately the same as in the southeastern Ohio fields, the rate
of decline could be expected to be approximately the same as that found
in southeastern Ohio.

Mr. Johnson proposes the hypothesis, in his fifth conclusion, that it
is characteristic of fields older than Devonian to show poor persistence.
Any such hypothesis is unnecessary. It usually is a self-evident fact
that these fields will not produce as much oil per unit as the fields of
younger geological age. As a rule, the oil is less viscous, the sands thinner,
less porous, and more compact.

The word " persistence" is misleading, for it indicates length of life
and the length of life depends, to a certain extent, on the price of oil. It
would be better to express the productiveness of fields in proportion per
acre. Furthermore, the word persistence, indicating length of life, when
applied to fields is very misleading, for the reason that the life of a field
or of a tract of land is roughly proportional to the size of the field, or to
the size of the tract. Life or persistence should not be expressed for a
field, for the life of a field or of a tract depends on the rate at which that
field or tract is drilled up and on the margin of profit derived from the
oil. These terms may easily be expressed to signify the length of life of
wells, for the production of individual wells of limited life make up the
production of the tract or of the field. The great length of life in some
eastern fields is due, first, to the price of oil and, next, to the size of the
fields and the slowness of drilling. The life of individual wells possibly
has been lengthened by the price of oil. Probably in very few cases
will the life of a well be as long as that of the field or of the tract.

Mr. Johnson's conclusions on the fallacy of the barrel-day price of a
property cannot be emphasized too strongly. This method of purchasing
producing properties is a gage of doubtful value, and has no engineering
basis. As a general rule, it will be found that, as the prospects of future
production become better, the value of the property, as determined by
the barrel-day price, will automatically be reduced, for the reason that

DISCUSSION 373

the users of this method of valuing properties do not accurately gage the
quantity of future production available. Even though the possibilities
are accurately gaged, the value of the oil in the undrilled portion of the
tract cannot be easily expressed in the barrel-day price without making
an engineering appraisal. If it were possible to gage accurately the
prospects of obtaining oil in the drilled and undrilled portions of the
tract, and the barrel-day price were raised or lowered accordingly, such
a method would be worth while. It is not to be denied that the method
has some merit as a rough gage of oil-land values.

R. H. JOHNSON. Mr. Washburne asks how it is possible that any of
these figures should be less than a year's production. The reason is that
a year might be represented by one section of the curve and another year
might be represented by a section of the curve that overlaps the first,
instead of leaving more or less of a gap outside. It means that less than
a year suffices to bring about the stated drop in average.

When Mr. Beal asks for the acre-yield data, he is asking for the
impossible, so far as the manual is concerned, because it does not give the
acreage. It was desirable to have that information in the manual, but
those who got out the manual had a large task to accomplish in a limited
period of time, so that the acre-yield together with other desirable data
could not be obtained.

I want to make a plea for that word "persistence; " we need a word for
this attribute, which is extremely important. It is an attribute we have
to talk about and handle, and it seems to me we should have a name for
it. What would be helpful would be a better name, but until we get a
better one, we need this one.

THE CHAIRMAN (RALPH ARNOLD, Los Angeles, Calif.). The term
" persistence of a well" or "persistence of a field" would overcome Mr.
Beal's criticism.

374 APPLICATION OP TAXATION REGULATIONS

Application of Taxation Regulations to Oil and Gas

Properties

BY THOMAS Cox, NEW YORK, N. Y.

(St. Louis Meeting, September, 1920)

THIS paper makes no claim to any new idea; it simply reviews the
Treasury Department Regulations pertaining to the practical applica-
tion of depreciation and depletion and other allowances governing taxa-
tion of oil and gas properties. Other methods may be existent, but as
they may not conform to the legal status they must be discarded.

In complying with the present laws governing the industry with regard
to taxation and the allowable deductions therefrom, the following con-
siderations are essential: Depletion, depreciation, amortization, other
allowances, and items not deductible.

It is definitely understood that depletion is the loss or exhaustion sus-
tained in the continuous operating of an oil and gas property, and that
each unit of oil or gas taken out reduces the value of the property until
its final exhaustion. Depletion applies only to the natural deposits
of oil and gas due to their removal in the course of exploitation of any
property.

Depredation is defined to cover the waste of assets due to exhaustion,
wear and tear, and obsolescence of the physical property, and is separate
and distinct from depletion; its allowance is that amount which should be
set aside for the taxable year in such sums as for the useful life of the
property will suffice to repay its original cost or its value as of Mar. 1,
1913, if acquired by the taxpayer before that date less the salvage value
at the end of such useful life.

Amortization is allowed for such facilities as were built or acquired on
or after Apr. 6, 1917, for the production of articles contributing to the
prosecution of the war and, in the case of vessels, those built and acquired
after that date. The amount to be extinguished, in general, is the excess
of the unextinguished or unrecovered cost of the property over its maxi-
mum value under stable post-war conditions.

Claims for amortization must be unmistakably differentiated in the
returns from all other claims of depreciation. The taxpayer is also re-
quired to furnish full information with the claims for amortization to
the full satisfaction of the Commissioner. Further reference is directed
to the specific rules and regulations for making these claims.

THOMAS COX 375

Other allowances are: cost of development, all operating expenses,
repairs, taxes, losses, personal services, bonuses to employees, damages,
abandoned wells, same as individuals.

Items not deductible are: donations to employees, losses in illegal
transactions, indeterminate oil losses, accrued deductions not charged in
prior years, depletion for past years.

ACCOUNTS

In order to carry out the intention of the Government regulations,
and to render the returns properly, it is essential that books of accounts
be kept to conform to the schedules issued by the Treasury Department.

Every taxpayer claiming and making a deduction for depletion and
depreciation of mineral property shall keep accurate ledger accounts in
which shall be charged the fair market value as of Mar. 1, 1913, or within
30 days after the date of discovery, or the cost, as the case may be,
of the property, and of the plant and equipment, together with such
amounts expended for development of the property or additions to plant
and equipment since that date as have not been deducted as expense in
his returns.

These accounts shall be credited with the amount of the depreciation
and depletion deductions claimed and allowed each year, or the amounts
of the depreciation and depletion shall be credited to depletion and de-
preciation reserve accounts, to the end that, when the sum of the credits
for depletion and depreciation equals the value or the cost of the property
plus the amount added thereto for development or additional plant and
equipment, less salvage value of the physical property, no further de-
duction for depletion and depreciation with respect to the property will
be allowed.

Because of the fact that depreciation and depletion deductions are
applied against different capital sums, which are usually returnable at
different rates, it is essential that these accounts be kept separately; that
is, the cost or value of the physical property subject to depreciation with
deductions for depreciation enter into one account, while the cost or value
of the property (exclusive of physical property) together with additions
for such development costs as have not been charged to current operating
expenses or deducted as depletion, enter into a separate account.

If dividends are paid out of a depletion or depreciation reserve the
stockholders must be expressly notified that the dividend is a return of
capital and not an ordinary dividend out of profits.

It is, therefore, necessary to reflect in the books of accounts and
records such items as are required to be filled in on the Treasury De-
partment questionnaire, in so far as it pertains to the taxpayer.

376 APPLICATION OF TAXATION REGULATIONS

Maps that accompany the records and statements must be sufficient
to show the property in relation to section, township, and range lines,
and should have the name of the state, company, or individual, scale of
map, date of survey, and points of compass. All wells should be located
and company property designated to distinguish it from the property of
adjacent owners. The character of the wells should be properly indicated
by standard symbols explained in marginal note.

ESTABLISHING VALUE OF PROPERTY
Determination of Cost of Deposits

In any case in which a depletion or depreciation deduction is computed
on the basis of the cost or price at which any mine, mineral deposit, min-
eral rights, or leasehold was acquired, the owner or lessee will be required,
upon request of the Commissioner, to show that the cost or price at which
the property was bought was fixed for the purpose of a bona-fide pur-
chase and sale, by which the property passed to an owner, in fact as well
as in form, different from the vendor.

No fictitious or inflated cost or price will be permitted to form the
basis of any calculation of a depletion or depreciation deduction, and in
determining whether or not the price or cost at which any purchase or
sale was made represented the actual market value of the property sold,
due weight will be given to the relationship or connection existing between
the person selling the property and the buyer thereof.

Determination of Fair Market Value

A determination of the fair market value of an oil or gas property
(or the taxpayer's interest therein) is required :

1. In connection with the computation of depletion allowances:
(a) As of Mar. 1, 1913, in the case of properties acquired prior to that
date; and (6) at the date of discovery, or within 30 days thereafter, in the
case of oil and gas wells, discovered by the taxpayer on or after Mar. 1,
1913, and not acquired as the result of purchase of a proven tract or lease
where the fair market value of the property is disproportionate to
the cost.

2. In connection with computing the amount that may be included
in paid-in surplus, as of date of conveyance, where the tangible property
has been conveyed to a corporation by gift or at a value accurately es-
tablished or definitely known as at date of conveyance clearly and sub-
stantially in excess of the cash or of the par value of the stock or shares
paid therefor.

3. In connection with the computation of profit and loss from sale of
capital assets in the case of properties acquired prior to Mar. 1, 1913.

THOMAS COX 377

Where the fair market value of the property at a specified date, in
lieu of the cost thereof, is the basis for depletion and depreciation de-
ductions, such value must be determined, subject to approval or revision
by the Commissioner, by the owner of the property in the light of con-
ditions and circumstances known at that date, regardless of later dis-
coveries or developments in the property or in the methods of extraction.

No rule or method of determining the fair market value of mineral
property is prescribed, but the Commissioner will lend due weight and
consideration to any or all factors and evidence having a bearing on the
market value, such as: (a) Cost, (6) actual sales and transfers of similar
properties, (c) market value of stock or shares, (d) royalties and rentals,
(e) value fixed by the owner for the purposes of the capital stock tax,
(/) valuation for local or state taxation, (g) partnership accountings,
(h) records of litigation in which the value of the property was in question,
(i) the amount at which the property may have been inventoried in pro-
bate court, (j) disinterested appraisals by approved methods, (k) other
factors.

The decline curve method is one of the most reliable for making ap-
praisals of oil properties. By this, one can estimate and compute the
recoverable oil contents of the property and thus arrive at a reasonable
unit cost for making the proper annual depletion charge. This method
has been tested and has proved efficient and acceptable. A constant record
is thus provided for all future variations and additions to the property.

REVALUATION OF PROPERTY NOT PERMITTED

The cost of the property or its fair market value at a specified date,
as the case may be, plus subsequent charges to capital sum not deductible
as current expenses, will be the basis for determining the depletion and
depreciation deductions for each year during the continuance of the
ownership under which the fair market value or cost was fixed; and during
such ownership there can be no revaluation for the purpose of this de-
duction. This rule will not forbid the redistribution of the capital sum
over the number of units remaining in the property, where erroneous
estimates have been revised with the approval of the Commissioner.

Valuation of Fee under Lease

The valuation of a fee ownership in oil or gas land under lease ac-
quired prior to Mar. 1, 1913, will have to do with the equity in its oil and
gas contents remaining to the owner of the fee title after deducting the
value of the lessee's rights. But subsequent investments or discoveries
by the lessee will not affect the lessor's valuation.

378 APPLICATION OF TAXATION REGULATIONS

Proof of Discovery and Allowances

The following articles in Regulations 45 have been amended in Treas-
ury Decision 2956, to read as follows:

' Article 220, Oil and Gas Wells. Section 214 (a) (10) and section 234 (a) (9) pro-
vide that taxpayers who discover oil and gas wells on or after Mar. 1, 1913, may,
under the circumstances therein prescribed, determine the fair market value of such
property at the date of discovery or within 30 days thereafter for the purpose of as-
certaining allowable deductions for depletion. Before such valuation may be made
the statute requires that two conditions precedent be satisfied:

(1) That the fair market value of such property (oil and gas wells) on the date of
discovery or within 30 days thereafter became materially disproportionate to the cost,
by virtue of the discovery, and

(2) that such oil and gas wells were not acquired as the result of purchase of a
proven tract or lease.

Article 220 (a) Discovery, Proven Tract or Lease, Property Disproportionate Value.
(1) For the purpose of these sections of the Revenue Act of 1918, an oil or gas well
may be said to be discovered when there is either a natural exposure of oil or gas, or
a drilling that discloses the actual and physical presence of oil or gas in quantities
sufficient to justify commercial exploitation. Quantities sufficient to justify com-
mercial exploitation are deemed to exist when the quantity and quality of the oil or
gas so recovered from the weH are such as to afford a reasonable expectation of at
least returning the capital invested in such well through the sale of the oil or gas, or
both, to be derived therefrom.

(2) A proven tract or lease may be a part or the whole of a proven area. A proven
area for the purpose of this statute shall be presumed to be that portion of the pro-
ductive sand or zone or reservoir included hi a square surface area of 160 acres having
as its center the mouth of a well producing oil or gas hi commercial quantities. In
other words, a producing well shall be presumed to prove that portion of a given sand,
zone or reservoir which is included in an area of 160 acres of land, regardless of private
boundaries. The center of such square area shall be the mouth of the well, and its
sides shall be parallel to the section lines established by the United States system of
public-land surveys in the District hi which it is located. Where a district is not
covered by the United States land surveys, the sides of said area shall run north and
south, east and west.

So much of a taxpayer's tract or lease as lies within an area proven
either by himself or by another is a " a proven tract of lease/' as contem-
plated by the statute, and the discovery of a well thereon will not entitle
such taxpayer to revalue such well for the purpose of depletion allowances,
unless the tract or lease had been acquired before it became proven. And
even though a well is brought in on a tract or lease not included in a
proven area as heretofore defined, it may not entitle the owner of the
tract or lease in which such well is located to revaluation for depletion
purposes, if such tract or lease lies within a compact area which is im-
mediately surrounded by proven land and the geologic structural condi-
tions on or under the land so enclosed may reasonably warrant the belief
that the oil or gas of the proven areas extends thereunder. Under no
circumstances is the entire area to be regarded as proven land.

THOMAS COX 379

(3) The property which may be valued after discovery is the well. For the pur-
poses of these sections the well is the drill hole, the surface necessary for the drilling
and operation of the well, the oil or gas content of the particular sand, zone or reser-
voir (limestone, breccia, crevice, etc.) in which the discovery was made by the drill-
ing and from which the production is drawn, to the limit of the taxpayer's private
bounding lines, but not beyond the limits of the proven area as heretofore provided.

(4) A taxpayer to be entitled to revalue his property after Mar. 1, 1913, for the
purpose of depletion allowances must make a discovery after said date and such dis-
covery must result in the fair market value of the property becoming disproportionate
to the cost. The fair market value of the property will be deemed to have become
disproportionate to the cost, when the output of such well of oil or gas affords a rea-
sonable expectation of returning to the taxpayer an amount materially in excess
of the cost of the land or lease if acquired since Mar. 1, 1913, or its fair market value on
Mar. 1, 1913, if acquired prior thereto, plus the cost of exploration and development
work to the time the well was brought in.

Article 221, Proof of Discovery of Oil and Gas Wells. In order to meet the require-
ments of the preceding article to the satisfaction of the Commissioner, the taxpayer
will be required, among other things, to submit the following with his return:

A map of convenient scale, showing the location of the tract and discovery well
in question and of the nearest producing well, and the development for a radius of at
least 3 mi. from the tract in question, both on the date of discovery and on the date
when the fair market value was set.

A certified copy of the log of the discovery well, showing the location, the date
drilling began, the date of completion and the beginning of production, the formations
penetrated, the oil, gas and water sands penetrated, the casing records, including the
record of perforations, and any other information tending to show the condition of the
well and the location of the sand or zone from which the oil or gas is produced on
date discovery was claimed.

A sworn record of production, clearly proving the commercial productivity of the
discovery well.

A sworn copy of the records, showing the cost of the property.

A full explanation of the method of determining the value on the date of discovery
or within 30 days thereafter, supported by satisfactory evidence of the fairness of
this value.

INVESTED CAPITAL

The invested capital is defined in section 326 of the Revenue Act
of 1918, as: Actual cash bona fide paid in for stock or shares; cash value
of property, other than cash, bona fide paid in for stock or shares (as
limited by the statute); and paid-in or earned surplus and undivided
profits, not including surplus and undivided profits earned during the
year. The surplus and undivided profits, if not correctly reflected in
the taxpayer's accounts, may be adjusted in accordance with the regu-
lations. These considerations are shown in the paragraphs relating to
surplus and undivided profits.

Surplus and Undivided Profits, Allowance for Depletion and Deprecia-
tion. Depletion, like depreciation, must be recognized in all cases in
which it occurs. Depletion attaches to each unit of mineral or other
property removed, and the denial of a deduction in computing net income

380 APPLICATION OP TAXATION REGULATIONS

under the Act of Aug. 5, 1909, or the limitation upon the amount of the
deduction allowed under the Act of Oct. 3, 1913, does not relieve the corpo-
ration of its obligation to make proper provision for depletion of its
property in computing its surplus and undivided profits.

Adjustments in respect of depreciation or depletion in prior years will
be made or permitted only on the basis of affirmative evidence that at
the beginning of the taxable year the amount of depreciation or depletion
written off in prior years was insufficient or excessive, as the case may be.
Where deductions for depreciation or depletion have either on the books
of the corporation or in its returns of net income been included in the
past in expense or other accounts, rather than specifically as depreciation
or depletion, or where capital expenditures have been charged to expense
in lieu of depreciation or depletion, a statement indicating the extent to
which this practice has been carried should accompany the return.

Surplus and Undivided Profits Reserves for Depreciation or Depletion.
If any reserves for depreciation or for depletion are included in the
surplus account, the account should be analyzed so as to separate re-
serves and leave only real surplus. Reserves for depreciation or deple-
tion cannot be included in the computation of invested capital, except
to the following extent: Excessive depletion or depreciation included
therein and which, if charged off, could be restored under article 340
may be included in the computation of invested capital; and where de-
preciation or depletion is computed on the value as of Mar. 1, 1913,
or as of any subsequent date, the proportion of depreciation or depletion
representing the realization of appreciation of value at Mar. 1, 1913,
or such subsequent date may, if undistributed and used or employed in
the business, be treated as surplus and included in the computation of
invested capital.

For the purpose of computing invested capital, depreciation or de-
pletion computed on the value as of Mar. 1, 1913, or as of any subsequent
date, shall, if such value exceeded cost, be deemed a pro rata realization
of cost and appreciation and be apportioned accordingly. Except as
above provided, value appreciation (even though evidenced by an
appraisal) that has not been actually realized and reported as income for
the purpose of the income tax cannot be included in the computation of
invested capital and, if already reflected in the surplus account, it must
be deducted therefrom.

The term capital sum is here applied to the total amount returnable
to the taxpayer through depletion, depreciation and obsolescence al-
lowances. It is to be clearly distinguished from the term invested
capital, which is the basis for the determination of war-profits credits
and excess-profits credits of corporations. Invested capital is the actual
cash, or its equivalent, paid in plus undistributed surplus profits, and no
appreciation in the value of any asset may be included except as provided
in article 844 (2).

THOMAS COX 381

Where amortization is allowed, such sum cannot be restored to the
invested capital for the purpose of the war-profits and excess-profits
tax, nor any portion of the amount covered by such allowance.

Capital Sum and Invested Capital

The capital sum has no necessary relation to the invested capital.
It may represent the investment of funds belonging to the taxpayer, or
the investment of borrowed funds, which have no relation to invested
capital; under the provisions of the law and regulations, the capital sum
may include amounts based on the right of valuation as of Mar. 1, 1913,
or within 30 days after the discovery of oil or gas by the taxpayer.

Where such valuations are allowable, they have no application to
invested capital, except in accordance with subdivision (2) in the pre-
ceding paragraph pertaining to surplus and undivided profits reserve
for depreciation or depletion, and may not be used for any purpose other
than as a basis on which to determine the gain or loss arising from the
sale or surrender of property acquired prior to Mar. 1, 1913. With re-
spect to any allowance for amortization, the basis is the cost of the prop-
erty acquired after Apr. 5, 1917, and no amount may be added on account
of revaluation.

Certain deductions from gross income are based on the capital sum;
credits are based on invested capital. It is necessary that these terms be
clearly understood by the taxpayer in order to avoid confusion in making
returns. In general, the deductions from gross income allowed corpora-
tions are the same as allowed individuals, except that corporations may
deduct dividends received from other corporations subject to the tax and
may not deduct charitable contributions.

DETERMINATION OF QUANTITY OF OIL IN GROUND

In the case of either an owner or lessee, it will be required that an
estimate, subject to the approval of the Commissioner, shall be made of
the probable recoverable oil contained in the territory with, respect to
which the investment is made as of the time of purchase, or as of Mar. 1,
1913, if acquired prior to that date, or within 30 days after the date of
discovery, as the case may be. The oil reserves must be estimated for
undeveloped proven land as well as producing land. If information sub-
sequently obtained clearly shows the estimate to have been materially
erroneous, it may be revised with the approval of the Commissioner.

The estimate of probable recoverable oil in the ground is fundamen-
tally necessary if a reasonable deduction for depletion is to be calculated
and, while it may be impossible to determine exactly the future produc-

382 APPLICATION OF TAXATION REGULATIONS

tion of a well or tract, it has been found possible to predict future pro-
ductions with a comparatively narrow limit of error. The result of
analysis of a great volume of production records has led to the develop-
ment of the methods suggested in the following paragraphs. It is good
practice to reduce estimates to the per acre basis of the contents of the
well; this affords a reasonable check on such estimates.

METHODS OP ESTIMATING RECOVERABLE RESERVES

The Treasury Department does not prescribe any particular method
of estimating recoverable reserves, but the methods described herein
are suggested as applicable to a wide variety of conditions. The under-
lying principle of the methods outlined is that the best indication of the
future production of any well is to be found in the history of similar wells
in the same or similar districts, and that, other things being equal, a
well's production is more likely to approximate the production of a simi-
lar well in the tract or district than to deviate widely from the average.
The method may be summarized as follows:

1. Plotting the record of production of individual wells, or, lacking
such detailed information, the average production per well for each tract.

2. Deriving from these graphical records an average or composite
production decline curve for the district.

3. Estimating from the last year's average production per well the
probable future production, based on the average production decline
curve, or a future production curve derived from the production decline
curve.

4. Ascertaining probable total future production of producing wells
by multiplying average future production per well by the number of wells
producing at the end of the year.

5. Estimating the probable future production of undeveloped proven
land on the basis of nearby production, making due allowance for the
decline in pressure due to the extraction of oil from the pool.

It is to be emphasized that the value of estimates will depend almost
entirely on the skill with which the method is carried out and the char-
acter of the production records on which they are based. Where accurate
detailed records are not kept, it may be difficult to determine a reasonable
allowance for depletion.

The taxpayer may estimate his recoverable reserves by any method
that can be shown to be well founded, but in all cases the data on which
such estimate was based must be submitted, with a description of the
method employed, and a resume* of the calculations.

COMPUTATION OF ALLOWANCE FOR DEPLETION OF OIL WELLS

When the cost or value as of Mar. 1, 1913, or within 30 days after the
date of discovery of the property, shall have been determined and the

THOMAS COX 383

number of mineral units in the property as of the date of acquisition or
valuation shall have been estimated, the division of the former amount by
the latter figure will give the unit value for the purposes of depletion, and
the depletion allowance for the taxable year may be computed by multi-
plying such unit value by the number of units of mineral extracted during
the year. If, however, proper additions are made to the capital account
represented by the original cost or value of the property, or circumstances
make advisable a revised estimate of the number of mineral units in the
ground, a new unit value for purposes of depletion may be found by di-
viding the capital account at the end of the year, less deductions for de-
pletion to the beginning of the taxable year which have or should have
been taken, by the number of units in the ground at the beginning of the
taxable year. This number, unless a revision of the original estimate has
been made, will equal the number of units in the ground at the date of
original acquisition or valuation, less the number extracted prior to the tax-
able year. If, however, recalculation is made, the number of units at the
beginning of the year will be the sum of the gross production of the year
and the estimated mineral reserves in the property at the end of the year.

Each barrel of oil or unit of gas extracted and marketed must, before
a profit can be realized, pay not only its proportionate share of the oper-
ating expense and deductions for depreciation and obsolescence of physi-
cal property, but also must pay its proportionate share of capital sum
returnable through depletion allowances. This proportionate share of
capital sum returnable through depletion allowances that each unit of
oil or gas must pay is unit cost.

Unit cost is obtained by dividing the capital sum returnable through
depletion by the estimated recoverable reserve at the beginning of the
taxable year. The depletion deduction is computed by multiplying the
unit cost by the number of units produced during the taxable year.

It is to be noted that the estimated recoverable reserves and the num-
ber of units produced are used in estimating the depletion deduction for
both lessor and lessee. Since, however, they are applied to different
capital amounts returnable through depletion deductions, the unit costs for
lessee and lessor are not identical, and the deductions bear the same ratio
as the capital sum of lessor and lessee. Usually the lessee's investment is
greater than the lessor's and his deductions are correspondingly greater.
Stated in another way, if a certain proportionate part of the lessee's
capital returnable through depletion deductions is deducted in a given
year, the same proportion of the lessor's capital sum returnable through
depletion will be deducted.

Computation of Depletion Allowance for Combined Holdings of Oil Properties

The recoverable oil belonging to the taxpayer shall be estimated sep-
arately on the smallest unit on which data are available, such as individual

384 APPLICATION OF TAXATION REGULATIONS

wells or tracts, and these, added together into a grand total, are to be
applied to the total capital assets returnable through depletion. The
capital sum shall include the cost or value, as the case may be, of all oil
rights, freeholds, or leases, plus all incidental costs of development not
charged as expense. The unit multiplied by the total number of units
of oil produced by the taxpayer during the taxable year from all of the
oil properties will determine the amount that may be allowably deducted
from the gross income of that year. In the case of sale of particular
tracts, full account must be taken of the depletion of such tracts in com-
puting profit or loss thereon.

A convenient summary record may be kept of acreage and production
with average decline curves of wells if leases are contiguous, or if property
consists of many separate leases or districts, one curve should be made for
each. Such a summary form would be a permanent record and greatly
assist in making up the annual returns. Each lease having its own de-
cline curve and production can be balanced out with the reserves at the
end of each year. New additions brought in during the year must be
added and carried out in accordance with the general plan.

COMPUTATIONS OF ALLOWANCE FOR DEPLETION OF GAS WELLS

The deductions allowed in computing income from natural-gas prop-
erties are in general similar to those allowed oil operators, but the method
of computing the deductions and the various assets differ in certain
particulars, the most notable of which are involved in the problems of
estimating the probable reserves and computing the depletion. On
account of the peculiar conditions surrounding the production of natural
gas, it is necessary to compute the depletion allowance for gas properties
by methods suitable to the particular cases. Usually the depletion should
be computed on the basis of decline in closed or rock pressure, taking into
account the effects of water encroachment and any other modifying
factors. In many fields, more or less additional evidence on depletion is
to be had from such considerations as: Details of production and per-
formance records of well or properties; decline in open flow capacity;
comparison with the life histories of similar wells or properties, particu-
larly those now exhausted; and size of reservoir and pressure of gas.

Methods of Computing Gas Depletion

Gas depletion may be computed from the details of production or the
performance record of the well or property, estimating, from its best
records, the quantity the well may be expected to produce and also the
rate of production. The decline in open flow capacity indicates the rate
of exhaustion.

Depletion may also be computed by a comparison with the life history

THOMAS COX 385

of similar wells or properties, particularly those exhausted or nearing
exhaustion; also by comparing the size of the reservoir and the pressure
of gas or by the pore space method. The factors that make this method
difficult to apply are the difficulties of accurately ascertaining the thick-
ness of pay, limits of pool, percentage of pore space, effect of encroach-
ing oil or water, and the quantity of gas remaining when production is
no longer possible.

Other indications of depletion are the decreasing supply by general
observation, by minute pressure changes, and by line pressure observed at
compressing stations. The appearance of water or oil in a gas well may
be the significant symptom of the approaching termination of the life of
the well. Clogging by paraffine, salt, or other deposits may demand the
modification of depletion estimates.

Closed, or Rock, Pressure Method

This is the best method of estimating the depletion of gas properties
as the rock pressure can be ascertained with a fair degree of accuracy, and
the pressure decline established, based on Boyles' law. In gaging, care
must be taken to insure that the gage is accurate; it should be tested both
before and after being attached to the well. Care must also be taken
to empty the well of oil and water and the well should be closed long
enough to allow the pressure to build up to its maximum.

Several corrections and refinements are made in applying this method
to the computation of depletion; it does not afford data on the amount of
gas originally in the pool, but only the portion of the gas that has been
removed. The atmospheric pressure must be taken into consideration
when taking the difference of gage, adding the same to each condition
in making the fraction remaining in the ground. Account should also be
taken of pressures at which wells are abandoned in the district.

Unit Cost as Applied to Natural Gas

The unit-cost method can be used by regarding pounds of closed
pressures as units, for the actual quantity of gas commonly varies with
the decline in pressure. The relative quantities at the beginning and
end of the tax year, and at the time of abandonment, may be used for
tax purposes when better information is lacking.

Apportionment of Depletion Among Various Sands

Where more than one sand under a property is yielding gas, the prob-
lem arises as to how to weight or evaluate the decline in pressure in the
different sands. The depletion sustained is not indicated by the average
decline in pressure, but is more nearly proportionate to the decline in the
good sand. If accurate figures on capacities of wells are obtainable, it
will be possible to make a fairly accurate weighting of the pressure de-

VOL. LXV. 25.

386 APPLICATION OF TAXATION REGULATIONS

clines; or if facts indirectly indicating capacity of individual wells are
obtainable, some light may be thrown on the question. But, as a general
rule, it is necessary to average the decline of wells drawing from differ-
ent sands as though they were drawing from the same sand.

Testing is recommended in summer or early fall. Abandoned wells
may be regarded as fully depleted and their pressure counted as zero in
computing depletion. It is suggested that the capital sum at the be-
ginning of each year be treated as 100 per cent., for the average pressure
at the beginning of the year and the average decline during the year will
then furnish a readily usable basis for computing the depletion allowance.

The following formula has been recommended for use by the Treasury
Department:

- X 2 = Depletion allowance

in which x = capital sum to end of the year; y= total future pressure de-
cline, or difference between sum of pressures at beginning of the tax year
and the sum of pressures at time of expected abandonment; z = pressure
decline during year as obtained by adding to sum of pressures at begininng
of year the sum of pressures of any new wells completed during year and
subtracting sum of pressures at end of year.
The formula may also be written as follows:

Capital sum to the end Sum of pressures at be-

of tax year ginning of tax year +

Sum of pressures at be- x sum of pressures of new = Depletion allowance .

ginning of year sum of wells sum ol pressures

pressures at time of ex- at end of tax year

pected abandonment

The regulations require gas-well pressure records to be kept, and where
the field is too new to determine the quantity in reserve a tentative esti-
mate will apply until production figures are available from which an
accurate estimate may be made.

Computation of Depletion Allowance for Combined Holdings of
Gas Properties

In the case of gas properties, the depletion allowance for each pool
may be computed by using the combined capital sum returnable through
depletion of all tracts of gas land owned by the taxpayer in the pool and
the average decline in rock pressure of all the taxpayer's wells in each pool
in the formula given in article 211. The total allowance for depletion
of the gas properties of the taxpayer will be the sum of the amounts com-
puted for each pool.

THOMAS COX 387

The depletion of gas supplies belonging to a taxpayer may be more
accurately computed by making estimates for each tract, though it is quite
possible that the expense of making separate estimates for individual
tracts may be greater than the benefits arising from such a procedure.

DEPRECIATION

The Treasury Department has issued many suggestions pertaining
to depreciation of physical property. Individual companies may apply
different rates of depreciation on equipment of a similar nature if the
rates are derived from reliable records kept by the respective companies.
It is specifically stated in the regulations that each claim for depreciation
must show facts upon which such claim is based. Special claims receive
special consideration.

Depreciation deductions are to be charged to a reserve fund, and are
in addition to any regular charge for repairs and operating maintenance.
For the general equipment of a producing property, depreciation may be
charged at the same rate as depletion because the general well equipment
is serviceable only as long as the life of the wells. This method makes a
simple and consistent form for such depreciation charges.

The summary of the suggestions in Table 1 is given as a convenient
method of reference, and is taken from the Treasury Department Manual
for the Oil and Gas Industry (see p. 1718).

OTHER ALLOWANCES

Development costs, except the cost of physical property, may be
deducted as an expense in the year in which they are paid out or, at the
option of the taxpayer, may be charged to capital returnable to the sev-
eral allowable deductions. Election once made under this option is final
and will control the returns for all subsequent years.

Cost of development comprises all payments made for and incident
to the drilling of wells, such as cost of:

Physical property, geological and other surveys made subsequent to
acquisition, roads, water supplies, hauling, wages, drilling, shooting,
overhead charges (incident to drilling of wells), fuel and all other similar
expenditures.

Both cost of property and cost of development, in so far as they have
not been decreased by allowable deductions, are chargeable to capital
sum and are returnable through the several allowable deductions. Struc-
tures and equipment may also be included in capital assets and are
returnable through depreciation. In the case of revaluations as of Mar.
1, 1913, or within 30 days of a discovery by the taxpayer made subsequent
to Feb. 28, 1913, the value thus established plus subsequent costs not
otherwise deducted becomes the total of capital sum. This revaluation,
however, does not affect the invested capital, as previously noted.

388 APPLICATION OF TAXATION REGULATIONS

TABLE 1. Summary of Suggestions from Treasury Department Manual

Class

No.

Refer-
ence
Page

Useful
Life
Years

Annual De-
preciation,
Per Cent.

Drilling equipment

40-25-15-10

Wells

Dehydratore

Electric

Pipe and tanks

Tanks
Steel 5000-55,000 bbl

2500-5000 bbl

Galvanized-iron 500-2500 bbl

o IX

Less than 500 bbl. .

12/4

Wood . .

Movable tanks

Galvanized-iron 500-2500 bbl

11 L^

Less than 500 bbl

16K

Water tanks
500-2500 bbl

12 J4

Less than 500 bbl

Tools

33 LZ

Transportation equipment

33 K

Water plants

Electric* equipment

Machine shops

Buildings
Small wood

"Frame structure

fi 4Z

Corrugated-iron siding

16 H

Concrete

Brick

Steel

Pipe lines
Mains over 6 in diameter

414

Mains under 6 in. diameter

Gathering lines

Less 10 per cent, salvage
Pump stations . . .

Tank cars

1
1

Refineries
Class 1. Located at point assuring a long supply of crude
oil; or well-constructed plants.
Class 2. Located at points assuring supply of crude oil
for several years.
Class 3. Skimming plants and small refineries of poor
construction, or located at points where supply of
crude oil is not assured for a long period of time.
Sales or marketing equipment
Tankers ... ....

20
10
6

Barges

Filling stations
Class A. Ordinary wood or corrugated-steel construc-
tion.
Class B. Brick and concrete or extraordinary construc-
tion.
Distributing stations

10
10

20
10
10

Tank wagons
Motor

Horse

16%

Steel barrels

14 M

Track and switches

12H

1
2

Natural gas (utility companies)
Drilling equipment (see A 1)
Wells (see A-2)
Gas pipe lines
Mains

Gathering lines

City lines

Compressor stations . . . .

14 4

16?i

Field stations

Considered as a whole plant

Natural gas gasoline
Plant, compression with 20 per cent, salvage value
Absorption plants with 20 per cent salvage

4
4

35-20-15-10
35-20-15-10

THOMAS COX 389

Operating Expenses

Expense includes all amounts paid out (exclusive of amounts paid
for physical property and development charged to capital sum) incident
to the development and operation of producing properties and the
preparation of their product for market, such as costs of pumping,
cleaning, reshooting (including cost of torpedoes), gaging, storing, treat-
ing, reducing, repairs and maintenance, transporting, refining, conserving,
marketing, overhead expense, insurance, etc. The cost of repairs and
replacements made necessary through deterioration of equipment may be
charged off as expense, but if this is done the amount allowed as a de-
preciation deduction will be reduced. In all cases, items of expense
must be charged off as such for the year incurred and can neither be
deducted from the income of subsequent years as expense nor added to
capital sum.

Repairs

The cost of incidental repairs that neither materially add to the value
of the property nor appreciably prolong its life, but keep it in an ordinary
efficient operating condition, may be deducted as expense, provided the
plant or property account is not increased by the amount of such expendi-
tures. Repairs in the nature of replacements, to the extent that they
arrest deterioration and appreciably prolong the life of the property,
should be charged against the depreciation reserve.

Amounts expended for additions and betterments or for furniture and
fixtures that constitute an increase in capital assets or add to their value
are not a proper deduction, but such expenditures when capitalized may
be reduced through annual depreciation deductions.

Taxes

Federal taxes (except income, war-profits, and excess-profits taxes),
state and local taxes (except taxes assessed against local benefits of a
kind tending to increase the value of the property assessed), and taxes
imposed by possessions of the United States or by foreign countries
(except the amount of income, war-profits, and excess-profits taxes
allowed as a credit against the tax) are deductible from gross income.

Postage is not a tax. Amounts paid to states under secured-debts
laws in order to render securities tax exempt are deductible. Automobile
license fees are ordinarily taxes.

Losses

Losses sustained during the taxable year and not compensated for
by insurance or otherwise are fully deductible (except by non-resident

390 APPLICATION OP TAXATION REGULATIONS .

aliens) if: incurred in the taxpayer's trade or business; incurred in any
transaction entered into for profit; or arising from fires, storms, shipwreck,
or other casualty, or from theft.

They must usually be evidenced by closed and completed transactions.
In the case of the sale of assets, the loss will be the difference between the
cost thereof, less depreciation sustained since acquisition, or the value
as of Mar. 1, 1913, if acquired before that date, less depreciation since
sustained, and the price at which they were disposed of.

When the loss is claimed through the destruction of property by fire,
flood, or other casualty, the amount deductible will be the difference
between the cost of the property, or its value as of Mar. 1, 1913, and the
salvage value thereof, after deducting from the cost or value as of Mar.
1, 1913, the amount, if any, which has been or should have been set
aside and deducted in the current year and previous years from gross
income on account of depreciation, and which has not been paid out in
making good the depreciation sustained. But the loss should be reduced
by the amount of any insurance or other compensation received. Losses
in illegal transactions are not deductible.

Losses of oil and gas are of two kinds: Those that are unforeseen or
unavoidable, such as losses sustained through fire or accident; and those
that are anticipated and recognized as unavoidable under operating
conditions, such as evaporation of oil in storage, ordinary leakage, re-
refinery losses, etc. Usually losses of the latter class are indeterminate
as to amount and are absorbed, either implicitly or explicitly, in current
operating expenses or in cost of the oil or gas. Indeterminate losses
may be deducted from gross income.

Compensation for Personal Services

Among the ordinary anu necessary expenses paid or incurred in
carrying on any trade or business may be included a reasonable allowance
for salaries or other compensation for personal services actually rendered.
The test of deducibility in the case of compensation payments is whether
they are reasonable and are in fact payments purely for services.

Bonuses to Employees

Gifts or bonuses to employees will constitute allowable deductions
from gross income when such payments are made in good faith and as
additional compensation for the services actually rendered by the em-
ployees, provided such payments, when added to the stipulated salaries,
do not exceed a reasonable compensation for the services rendered.

Donations to employees and others, which do not have in them the
element of compensation or are in excess of reasonable compensation for
services, are considered gratuities and are not deductible from gross
income.

THOMAS COX 391

Damages

Any amount paid pursuant to a judgment or otherwise on account of
damages for personal injuries, patent infringements, or otherwise, is
deductible from gross income when the claim is liquidated or put in
judgment or actually paid, less any amount of such damages as may have
been compensated for by insurance or otherwise.

If subsequent thereto, however, a taxpayer has for the first time as-
certained the amount of a loss sustained during a prior taxable year, and
not deducted from the gross income therefor, he may render an amended
return for such preceding taxable year, including such amount of loss
in the deductions from gross income, and may file a claim for refund for
the excess tax paid by reason of the failure to deduct such loss in the
original return. Provided, that no such credit or refund shall be allowed
or made after five years from the date when the return was due, unless
before the expiration of such five years a claim therefor is filed by the
taxpayer.

Abandoned Wells

When wells collapse, become wet or otherwise unprofitable producers,
and are abandoned, the cost of such abandonment is chargeable to
current operations. Usually the value of the recovered material is
credited to its investment cost and the difference, not already depleted,
is deductible as being fully depleted.

In general, the deductions from gross income allowed corporations
are the same as allowed individuals, except that corporations may deduct
dividends received from other corporations subject to the tax and may
not deduct charitable contributions.

ITEMS NOT DEDUCTIBLE

Donations to employees or others that are not compensation or are in
excess of reasonable compensation for services are considered gifts and
are not deducted from gross income.

Losses in illegal transactions are not deductible.

Losses of oil and gas are of two kinds: (a) unforeseen or unavoid-
able, as through fire or accident; (6) anticipated and recognized as un-
avoidable under operating conditions, as evaporation, leakage, refinery
losses, etc. Usually the latter are indeterminate as to amount and are
absorbed either implicitly or explicitly in current operating expenses or
in cost of oil^or gas. Indeterminate losses may not be deducted from
gross income.

Accrued Deductions not Charged in Prior Years
The expenses, liabilities, or deficit of one year cannot be used to
reduce the income of a subsequent year. A person making returns on

392 APPLICATION OF TAXATION REGULATIONS

an accrued basis has the right to deduct all authorized allowances, whe-
ther paid in cash or set up as a liability; it follows that if he does not
within any year pay or accrue certain of his expenses, interest, taxes or
other charges, and makes no deduction therefor, he cannot deduct from
the income of the next or any subsequent year any amounts then paid in
liquidation of the previous year's liabilities. A loss from theft or embez-
zlement occurring in one year and discovered in another is deductible
only for the year of its occurrence.

Depletion for Past Years

Where under the Act of Oct. 3, 1913, or of Sept. 8, 1916, a taxpayer
has not been allowed to make a deduction for the full amount of his de-
pletion, the amount of such deficiency cannot be carried forward and
deducted in any later year. Depletion attaches to each unit of mineral
or other property removed, and a taxpayer should make proper provision
therefor in computing his net income. Under the Revenue Act of
1918, the amount recoverable through depletion will be the cost, or the
value as of Mar. I, 1913, or within 30 days of the date of discovery, as the
case may be, less proper allowance for the mineral or other property
removed prior to Jan. 1, 1918.

RESUME

The foregoing generally embraces a resume* of the Regulations and
methods of applying the valuation, and also the depletion, depreciation,
amortization, and other deductions from gross income, of gas and oil
properties, and are either copied or briefly condensed from the Treasury
Department Regulations 45. In the general application of these, the
taxpayer will, through his proper books of accounts, record all trans-
actions of capital, assets, reserves for depletion, depreciation, or amorti-
zation and other deductions, also distributions of investments to the
various facilities and cost of all buildings and equipment that will fully
reflect the business conditions. In order to set up the proper depletion
and depreciation deductions from gross income, it is necessary that an
investment be set up on each lease or property.

RECORDS OP PRODUCTION AND ESTIMATED RECOVERABLE OIL

Individual small tracts can be more readily made up than for very
large ones; in fact, for small properties computation by well areas make
a desirable and complete record.

Production records should be kept by individual wells, if possible,
or as few as are operated in a group. Complete records for each lease or
subdivision are desirable, as copies of such data are requested with the
questionnaire. If records of production of individual wells were kept,
decline curves would be both accurate and easy to produce.

DISCUSSION 393

All gage tickets should be preserved for a check of oil run and balance
with production and stocks. These, too, record the gravity of the oil.
The posted prices are recorded in the settlements for such oil.

Logs of wells should be filed and preserved and a proper working map
is necessary to show the location of each well and the position of the
property in relation to all adjoining leases. Water records should be
kept of each well and also time and method of each well's operations;
also records of suspensions or abandonment. These data are very useful
in connection with figuring depletion deductions.

If the property is large, the Geological Department defines the classes
of land and directs the calculations of oil reserves.

The difference between invested capital and capital sum is clearly
defined in the Regulations, as also the method for discovery revaluations.
In practical operation, the chief items in making up the tax returns neces-
sitate that the investments of each tract be properly set up; that the
reserves be figured, methods submitted with records of all productions,
checking or balancing the reserves both of past and end of current year
so that unit costs can be readily and accurately obtained.

The deductions for depletion, depreciation, and others are also readily
obtained from the proper method of charging, through the books of
accounts, supported by the usual records of production, shipments, well
data, acreage, royalties, and a general systematic business routine.

Generally the petroleum industry has adopted most of these methods,
and is conforming to the new orders and conditions. The Regulations
are drawn up with clarity to aid operators in making their returns, and
are worthy in their intent.

This paper is submitted through a desire to arrange the laws and
rulings as a concise reference and not with any intention of presenting
anything new.

Acknowledgment is made to Mr. F. J. Hoenigmann for assistance
and aid in compiling these pages.

DISCUSSION

RALPH ARNOLD, Los Angeles, Calif. The subject of taxation must be
considered from the standpoint of both the tax official and the taxpayer.
The needs of taxing jurisdiction are paramount in communities depen-
dent on mining or oil. When a man says, "Let us use the last production
tax or income tax," he is looking at the question from his own standpoint.
When there is no income or gross production, the needs of the community
in which the mine or well is situated are practically the same, so that
taxes must be paid or the government must fail. In such cases the
ad valorem system is better fitted to conditions.

Qf The question as to whether this discourages development has been
asked. In Wisconsin, where the ad valorem system is used for valuing

394 APPLICATION OF TAXATION REGULATIONS

iron-ore properties, ore has been developed until about two billion tons
are now in sight. In Arizona, also, this system has not interfered with
the development of new deposits.

In Minnesota, where the dominant electoral element is agricultural,
the taxes are based upon a fair market value of all properties, but the
assessment is 33J<$ per cent, of the value for agricultural property,
40 per cent, for urban properties, and 50 per cent, for mining properties.
This is a clear discrimination against mining. In Montana and Idaho,
where the dominant influence is mining, the system of taxation puts its
burden on the agricultural and other industries of the state. In Cali-
fornia, the assessment in Orange County is based on the fictitious value
established on the production of the previous year. It is assumed that
the property will last ten years and produce at the same rate so that value
is multiplied by ten to get full value and 40 per cent, of that is taken as
the assessable value of the property. If there should be a big produc-
tion one year and a small one in the next, as is often the case, the taxes
the second year would be out of all proportion to one's ability to pay, and
have no relation at all to the taxes on the surrounding real estate.

In its report, the Mine Taxation Subcommittee of the National
Tax Association advocated the placing of all taxes, especially for local
purposes, on the ad valorem basis; that is, treating mines, oil, and gas
properties the same as other classes of real estate.

The reason that this question of taxation is of great importance to
engineers and geologists is: If the ad valorem method is adopted,
and it probably will be adopted in many places, oil and gas properties
must be valued for purpose of taxation; that valuation will have to be
done by an engineer, it is not work for the ordinary assessor.

In the work for the government, it was necessary to employ engineers
to solve the tax problems. This question of valuation and taxation is
not a subject for lawyers, but for engineers. Just at the present tkne the
lawyers are handling most of the cases, which in many instances could
be better done by engineers.

What is the fair market value of the property? The tendency now
is for oil and mining companies to try to base the value on the
engineer's report. It is a hypothetical value, based on the present
worth of the estimated amount of mineral in the ground. The regula-
tions call for consideration of a number of factors in reaching this fair
valuation. All of these must be taken into consideration, and I do not
believe we are going to arrive at a fair market value by making any one of
those factors dominant for all localities, or for all types of property.

VALUATION FACTORS OF CASING-HEAD GAS INDUSTRY 395

Valuation Factors of Casing-head Gas Industry

BY OLIVER U. BRADLEY,* MUSKOGEE, OKLA.

(St. Louis Meeting, September, 1920)

THE utilization of casing-head gas in the manufacture of casing-head
gasoline by both the absorption and the compression method is a most
important factor in the conservation of our natural resources. Any
industry connected with the oil business, in general, possesses particular
attraction for a large number of people not conversant with its basic
principles, for the reason that the large fortunes made in the production
and utilization of petroleum and its products have been given undue
prominence. The general impression of the public that enormous profits
are to be realized in the casing-head gas industry with minimum expendi-
tures of both capital and effort has, in a large measure, accounted for
the phenomenal expansion of the industry in recent years and, likewise,
has resulted in many mistakes and loss of investment funds. It is true
that many installations have been very profitable, but such instances are
always the result of careful planning, experienced judgment and con-
servative estimates.

The inception and subsequent activity in the manufacture of casing-
head gasoline, enabling the business to assume an important position in
the petroleum industry, are of comparatively recent origin, as its greatest
growth, particularly in Oklahoma, occurred during the years 1917 and
1918. Much information must yet be secured and systematized con-
cerning the methods of manufacture of gasoline from high-yield casing-
head gas, and a large field is still open for the application of accumulated
experience and good engineering practice in devising better methods of
extracting gasoline from casing-head gas of the poorer grades.

The absorption process is coming into general use as a most efficient
system of treating casing-head gas, and even so-called dry gas. In fact,
there is a decided tendency toward the universal adoption of the absorp-
tion process as against compression methods. However, a general dis-
cussion of the relative merits of these two systems is not within the scope
of ^his article.

A few of the facts that must be given consideration in arriving at a
fair and ^impartial estimate of the actual investment value of the casing-
head gas business are the quantity of gas available, the quality and

* United States Oil and Gas Inspector.

396 VALUATION FACTOKS OF CASING-HEAD GAS INDUSTRY

composition of the gas, accessibility of plant to railroads and water sup-
ply, efficiency of operation of oil leases connected to plants, plant effi-
ciency, estimates of production and marketing costs, contract for purchase
of gas, and market price of casing-head gas.

QUANTITY OF GAS AVAILABLE

The most important factors are the quantity of casing-head gas
available and the conditions that will have a material bearing on its
future supply, such as location of field, depth of oil wells, initial rock
pressure, thickness and porosity of oil sands, relative position of oil and
gas strata in the sand, grade of oil, life of oil wells, location and rapidity
of water infiltration, vacuum carried, and regularity of its application.
More mistakes have been made in the estimation of the available supply
of gas than in any other feature of the business. It is at once appreci-
ated that as close a determination as possible of the marketable quantity
of casing head gas is of extreme importance. When volume tests are
made, it should be remembered that orifice tests of built-up pressure of
casing-head gas on individual wells do not necessarily indicate the per-
formance of these wells under vacuum conditions. The application of
the vacuum frequently increases the volume of both oil and casing-head
gas temporarily, but the effects of the continuous pperation of wells
under a vacuum cannot be clearly defined, as it is an open question as
to when and under what conditions a vacuum should be applied to oil
wells in order to produce the maximum extraction of both oil and casing-
head gas.

The exploitation of casing-head gas is quite different from ordinary
mining operations, as available sources of supply are not susceptible to
exact measurements, like ore in a mine, for example, which may be
developed by shafts and drifts, blocked out by raises and winzes, sampled
and assayed, and the mineral content closely estimated. Casing-head
gas, technically speaking, is not in place, cannot be stored, and, therefore,
must be treated and disposed of at once after being brought to the sur-
face. Many casing-head gasoline plants have been designed and erected
for the treatment of a certain estimated quantity of gas, which after two
or three months have found that the supply of gas has decreased more
than 50 per cent., necessitating the dismantling and removal of several
units of the equipment, or having on hand surplus machinery, which im-
poses a considerable handicap on the profitable operation of the business.
In the case of many plants in Oklahoma, if conservative engineering
estimates had been made at the beginning of operations, a smaller plant
would have been installed and additions made thereto, in case the supply
of gas justified them. In this way, the equipment could have been

OLIVER U. BRADLEY

397

enlarged to meet the requirements of the gas supply instead of reversing
the process.

The location of oil leases, with reference to the general producing
area of the pool, is important, as investigation has shown that when
leases are located on the edge of the pool the casing-head gas frequently
fails to maintain its usual volume, and its richness is much less than that
from wells in the main or central portion of the field. Consideration
should also be given to underground conditions in estimating the possi-
bilities of the supply of casing-head gas.

QUALITY AND COMPOSITION OP GAS

A chemical analysis of the gas should be made in order to determine
its actual physical characteristics, as a basis for applying a method that
will obtain a maximum yield of casing-head gasoline. Furthermore, a
practical field test should always be made, so as to secure dependable
information regarding the results that may reasonably be expected in
the operation of a plant. A demonstration of the desirability, as well
as the necessity, of applying both chemical and practical tests to casing-
head gas, is clearly shown in the accompanying data, giving percentage
loss due to evaporation in conducting tests to determine its correct
productivity.

No.
of
Test

Cubic
Feet
Used

Gasoline Un-
weathered,
Cubic Centi-
meters

Gasoline
Weathered,
Cubic Centi-
meters

Cubic Centi-
meters
Lost

Percentage of
Evaporation

Productivity
per 1000
Cu. Ft.

200

2,985

1,960

1,025

34.0

2.59

200

3,830

1,960

1,870

48.8

2.58

200

640

635

0.9

0.83

200

2,475

2,070

405

16.3

2.73

200

2,405

2,040

365

15.1

2.69

167

1,345

1,165

180

13.4

1.84

These tests were all made from casing-head gas from the Bartlesville
sand in the Gushing Field and illustrate the variability in the composition
of such gas, the higher fractions sometimes predominating and some-
times, the lower.

Conditions that may produce a considerable variation in the results
of tests may be summarized as follows: (1) The time of the year taken,
as climatic conditions and temperature have a bearing on the results.
(2) Conditions on the lease, such as wells on the pump or off, cleaning
out wells, and other lease work. (3) Point of sampling the gas and con-
ditions under which the sample is taken. (4) Improper design of ma-
chine, such as lack of cooling surface, inefficient compression, faulty

398 VALUATION FACTORS OP CASING-HEAD GAS INDUSTRY

manipulation, poor connections, and defects in mechanical equipment
designed to make these tests. (5) Natural error creeping in when small
quantities of gas are tested, together with incorrect meters. (6) Ex-
cessive evaporation in open-air field tests.

Because of the presence of one or more of these conditions, the results
of field tests are frequently too high or too low and, in calculating the
value of the gas, proper allowances should be made after a survey of all
the facts. If careful attention is given to the chemical analysis of the
gas and an effort is made to get a practical field test under as nearly as
normal conditions as possible, the chances of error in figuring commercial
yields are greatly reduced.

ACCESSIBILITY OF PLANT TO RAILROADS AND WATER SUPPLY

Plants are sometimes located unfavorably with regard to supply of
casing-head gas. It is frequently a debatable question as to whether
the plant should be located close to railroad facilities, with the supply of
gas several miles away, or close to the supply, with railroad facilities
several miles distant. The general factors relative to loading losses, cost
of upkeep of field lines, and general efficiency of plant operations should
be considered in selecting the location of a plant. Furthermore, a de-
pendable water supply is always important. Numerous plants have
been located where the initial expense of installing a suitable and ade-
quate water supply and its subsequent maintenance have been excessive,
thus imposing a heavy charge on the future profits of the business.

EFFICIENCY OF OPERATION OF OIL LEASES CONNECTED TO PLANTS

Serious friction may often arise between the operator of an oil lease
and the manufacturer of the casing-head gasoline. This contingency is
of particular importance, though it is frequently given no attention,
because the close relationship between the production of oil and casing-
head gas is not fully appreciated. Considerable inroads on the profits
of a casing-head gasoline plant may be made by undue irregularities in
the operation of oil leases, such as disconnecting wells at inopportune
times, cleaning out same, admission of air into lines through leaking
stuffingboxes and defective lead lines. Many difficulties of this sort
may be eliminated by the incorporation of certain provisions in casing-
head contracts. Practically all of the larger companies operate their
own casing-head gasoline plants, or this work is done by closely affiliated
or subsidiary companies, which is far more satisfactory from the stand-
point of efficiency, as there will be close cooperation between the oil-
producing department and the casing-head gasoline division.

OLIVER U. BRADLEY 399

PLANT EFFICIENCY

There are many methods of cooling the gas and its treatment under
varying pressures; also, many systems of blending are in use, all of which
have a material bearing on results. A resume* of the numerous practices
will not be given at this time. However, casing-head gasoline manu-
facturers should be willing to cooperate in comparing the various methods
employed, to the extent of giving independent investigators as much
information as possible, as the collection of reliable data on the efficiency
of different methods of handling the various grades of gas would benefit
the entire industry and need not necessarily make public the particular
trade secret of any company. Under the most careful management,
there will still remain considerable variations in plant operation, and
sometimes these differences will result in changes of production ranging
from 15 to 20 per cent, during any one month.

Some of the causes, not associated with the efficiency of plant opera-
tion, that will produce substantial changes in monthly productions of
plants are as follows:

1. Climatic conditions. An examination of the records of monthly
production of casing-head gasoline plants will show changes correspond-
ing to the seasons of the year, the production in the spring and fall
months usually being greater than that of the summer and winter
months.

2. Frequently, one or two of the wells will produce a different quality
of gas, when considered in connection with its gasoline productivity. If
the pressure on one well should be greater than on others, it will naturally
force proportionately more lean gas into the plant. This will often result
in a great difference in the daily production; on some days, this high
pressure will put a greater quantity of gas into the plant than on others.
The mixture of lean gases with the regular gas coming into the plant
will reduce the productivity of the entire volume of gas in a considerably
larger ratio than would be revealed if a test were made of the individual
productivities and an average taken. It has been found necessary, in
many plants, to cut out these lean wells in order to secure a reasonable
degree of uniformity in the average daily production.

3. It is necessary, in the operation of casing-head gasoline plants,
to guard against excessive amounts of air in the lines. Daily tests
should be made of the gas mixture entering the plant and the presence of
excessive amounts of air should be investigated and faulty conditions
remedied. Air not only has a direct bearing on the output of the plant
but is a source of considerable danger from explosion, when it reaches a
high percentage in the mixture.

The varying monthly results of plant operation may be shown by
the following tabulation:

400 VALUATION FACTORS OF CASING-HEAD GAS INDUSTRY

MONTH
April

TOTAL
GAS CONSUMED
CUBIC FEET

8 727 000

TOTAL
CONDBNSATE
PBODUCED
GALLONS

30034

May..

9,106,000

29382

June

9 389 000

18630

July..

9.877,000

20.741

GALLONS

PER 1000

CUBIC

FEET

3.44
3.23
1.98
2.10

ESTIMATES OF PRODUCTION AND MARKETING COSTS

Careful estimates should be made of the cost of labor and supplies,
superintendence, insurance, taxes, yearly depletion of gas supply, depre-
ciation of equipment, the unavoidable shipping losses, and the general
hazards of the business, such as inability to find a ready market for the
product, due to different specifications of purchasers as to gravity and
blending material.

In reality, the marketing factor frequently becomes a question of
vital concern. Most manufacturers of casing-head gasoline must now
supply their own cars, specially designed at considerable expense, not
only in order to comply with the Federal shipping regulations but to
avoid excessive evaporation losses and leakage.

CONTRACTS FOR PURCHASE OF GAS

Contracts for the purchase of casing-head gas have gone through the
various stages of development, or evolution, corresponding rather closely
to the expansion of the industry. In a general way, such contracts may
be divided into several distinct classes, viz.:

(a) The flat-rate contract in which there is a specified fixed rate per
thousand cubic feet for the gas, extending over a period coinciding with
the terms of the lease. These flat rates were made in the infancy of the
industry and, compared with present conditions, are extremely low, as
most of the instruments drawn for the purchase of casing-head gas in
the early days show a price ranging from 3 to 5 cents per thousand
cubic feet.

(6) Sliding-scale rate in which a certain price is specified for the gas,
based on the Chicago tank-wagon price for casing-head gasoline, or
f.o.b. loading rack price at plant, or a designated local market; that is,
3 cents per thousand cubic feet for the gas when the price of gasoline is
10 cents per thousand cubic feet, with % cent increase in the price per
thousand cubic feet for the gas for every 1 cent increase in the price of
gasoline. These sliding-scale contracts range from 3 cents on 10-cent
gasoline to 8 cents on 12-cent gasoline, with the percentage increase
feature. It will be noted that no mention is made of the productivity
of the casing-head gas.

OLIVER U. BRADLEY 401

(c) A fixed percentage of the gross proceeds derived from the sale of
casing-head gasoline produced. Contracts of this character, varying
from 25 to 50 per cent, of the gross proceeds are considered fair, as they
show exactly what the plant produces and the settlement for the gas is
made on such basis. Provisions are frequently incorporated in these
contracts, charging up the proportionate cost of the blend and its trans-
portation against the seller of the gas, particularly if the percentage of
gross proceeds is above 40 per cent. Some difficulty is encountered, at
times, in making settlements with royalty owners on the basis of plant
production, but from the standpoint of the lessee, who usually owns a
group of leases, the contracts are equitable.

(d) A test of the productivity of the gas and the Chicago tank-wagon
price per gallon for gasoline. The price of the gas is determined by a
schedule showing the yields of gasoline from the gas on a scale of %-gB,}.
units, arranged in a horizontal column, and the Chicago tank-wagon
price of gasoline, in a vertical column. Several kinds of schedules are
in use and are included in contracts, but the principle involved in each
is the same; the schedule shown in Table 1 was suggested to the De-
partment of the Interior by different casing-head gasoline producers
and was approved by that Department.

In contracts providing for a test of the gas, it is rare that any method
of procedure is prescribed for making the same. The ordinary equip-
ment and requirements of a field test of the productivity of casing-head
gas that will give reasonable satisfactory results may be specified as
follows :

1. A fairly dependable testing machine usually consists of a small
gasoline-engine unit, belted to a compressor, with coil racks, cooling
tanks, accumulator tanks, gages, meters, pipe connections and necessary
fittings, the entire equipment being portable. Coil racks should contain
at least 18 ft. (5.49 m.) of %-in. (9.53 mm.) galvanized-iron pipe in the
form of a spiral, and all lines from the compressor to the coils and from
the coils to the accumulator tank should have a natural drain so that all
condensate will move to the accumulator tank by its own gravity The
testing machine should be placed and jacked up with this end in view.

2. The compressor should make 250 r.p.m., in order to do the most
efficient work.

3. The casing-head gas to be tested should be taken from the dis-
charge of the vacuum pump or from the discharge of the low side of the
plant compressor at a pressure of 4 oz. at the intake of the meter.

4. All leases connected to the vacuum pump should be shut off except
the lease to be tested, when such is possible, and the main line should be
given time to clear itself of all mixed gases; or, a vacuum-pump unit
may be installed on the testing machine, thus enabling a sample of gas

VOL. LXV. 26.

402

VALUATION FACTORS OF CASING-HEAD GAS INDUSTRY

-s

A% ft l 1! I:

t-i 1-1 i-i-rH r-iHC<io<c^cN(NNeoeocococoeo

_| c.e.c.c...^.^^^

5 COt- 000 OrH W CO^. 50^000 rHN ^ CO t^ 00 O O

S i-l^-li-lrHTHr-tt-lt-I^H^IWMMMNWNMMOJCO

OLIVER U. BRADLEY 403

to be taken from any point on the field lines under vacuum, but such a
unit must be operated efficiently in order to get satisfactory results.

5. The usual vacuum should be pulled at the time of the test so that
the quality of the gas tested will be similar to that ordinarily utilized in
the plant in the manufacture of casing-head gasoline.

6. The temperature of the cooling coils should be between 50 and
60 F. (10 and 17 C.).

7. Scrubber tanks and lines at vacuum stations should be blown out
so as to eliminate waste oil and all foreign matter before making the test.

8. Gasoline should be drawn from the accumulator tanks at atmos-
pheric pressure. After measuring the contents, Baume* and temperature
readings should be taken.

9. A cubic centimeter jar should be used when weathering; warm
water is a satisfactory medium for slowly raising the temperature of
gasoline to normal, or 60 degrees.

10. The pressure on the accumulator tank at the time the test is run
should be the same as the pressure carried in the gasoline plant. After
the sample of gasoline is weathered to 60 F., the Baume* reading should
be noted.

11. In starting the test, build up the pressure of gas in the machine
and the accumulator tank to 300 lb., and note any leakage in the line
or connections of the machine. If no leaks appear, retain the pressure
at 300 lb. and blow off the accumulator tank until all liquid is discharged,
but do not let the pressure go below 250 lb., on the gage. Close the
valve and start reading the meter for the test.

12. If a scrubber tank is located between the compressor and the
accumulator, it should be drained of gasoline upon the completion of the
test, as some gasoline will always condense in it; this gasoline should be
added to the volume drawn from the accumulator, in order to get the
full volume of casing-head gasoline coming from the gas that has been
metered.

(e) Contracts in which the productivity of casing-head gas is deter-
mined by the results of plant production; that is, the total number of
gallons of condensate produced during the month is divided by the total
volume of casing-head gas utilized, which shows the average productivity
in gallons per thousand cubic feet of gas. The schedule shown in
Table 1, or one similar to it, may then be used in determining the price
of casing-head gas per thousand cubic feet.

(/) An ascending flat scale of prices on a yearly basis. For example,
15 cents for the first year, 20 cents for the second, 25 cents for the third,
and so forth, no reference being made to the productivity of the gas.

A casing-head gas contract constitutes a vital part of the investment
in the business and, therefore, the terms should receive careful attention.
The more important items, such as initial supply of gas, richness, and

404 VALUATION FACTORS OF CASING-HEAD GAS INDUSTRY

estimated percentage of yearly decline will certainly not be overlooked,
but minor considerations, such as the regularity of the vacuum carried
on wells, upkeep of field lines, and return of dry gas to the lease for
operating purposes frequently are not given sufficient consideration.
Instances are numerous where a provision for the return of a certain
amount of dry gas for lease purposes has made it necessary for the gaso-
line manufacturer to purchase dry gas and supply it at considerable ex-
pense to the operating company, in order to fulfill the terms of the contract.

MARKET PRICE OF CASING-HEAD GASOLINE

Market quotations for casing-head gasoline are a controlling factor
in the profitable or unprofitable aspect of the casing-head gas business;
it should be pointed out that casing-head gasoline is considered in a
different class to straight-run gasoline. The various methods of handling
this product blending into different grades, requirements of shipping
in order to make same acceptable to certain market demands, and the
commercial connections enabling a company to get its output before the
public are matters of grave concern to producers of casing-head gaso-
line. In conclusion, therefore, the general conditions in the business make
it necessary to take a long-range view, including an estimate of the prob-
able effect of future demands and trade conditions, as related to possi-
bilities of motor-fuel substitutes, from the standpoint of efficiency and
cost of production.

MODIFIED OIL-WELL DEPLETION CURVES

405

Modified Oil-well Depletion Curves

BY ARTHTTR KNAPP, M. E., SHREVEPOET, LA.

(New York Meeting, February, 1921)

OIL-WELL depletion curves, to be of value, should show when a well
or lease may no longer be operated at a profit. The difference, at any
time, between the total expenditures and the total income of a lease or
well may be called the lease status. Plotting this lease status against
time will give a curve subject to more accurate and different interpreta-
tions than the barrels-time curves.

According to the hypothetical barrels-time curves shown in Fig. 1,
well A, at the end of 16 mo., is producing twice as much oil as well B
and will continue to produce for another year whereas well B will cease
producing in about 6 months.

DATA FOB LEASE STATUS-TIME OR DOLLARS-TIME CURVE

Lease purchased for $3000

No expenses chargeable to lease for 3 mo

Well A is started; cost of drilling for month is $16,000

Well is completed at additional cost of $10,000

Well A is brought in and flows 10,000 bbl. first month (see

Fig. 1). Necessary to invest in tanks, boilers, pipe lines,

etc.; difference between expenditures and receipts gives

profit for month of $5,000

Investment is small, cost of operating well A is small, so

profits are $15,000

Well ceases to flow so there is additional investment for

pumping equipment and additional operating expense;

net earnings from 6,000 bbl. of oil produced is $4,000

Lease operation now becomes normal and curve becomes

smooth . ,

TIME
MONTHS

2
3

8
9

10
11
12
13
14
15
16

LEASE
STATUS

-$ 3,000

- 3,000

- 19,000

- 29,000

- 24,000

- 9,000

- 5,000

- 500
2,000
4,500
6,000
7,700
8,700
9,000
9,500

10,000

A hypothetical lease status-time, or dollars-time, curve of this lease
is shown in Fig. 2. At zero time, the lease is purchased for $3000, which
is plotted below the gerg dollar line, All subsequent entries are plotted

406

MODIFIED OIL-WELL DEPLETION CURVES

below this line until total receipts exceed the total expenditures, when
the curve crosses this line and shows a credit, or profit.

Fig. 1 shows that well A made 600 bbl. during the sixteenth month,
or 20 bbl. per day, and it indicates that an average daily production of

Bbls

Well A

Well B

6 12 18 24 6 12 18

Months Months

FIG. 1. HYPOTHETICAL BARBEL-TIME CURVES.

18 bbl. per day may be expected during the seventeenth month. But
using this curve to determine the probable profit leaves out of account
the gradual increase in the operating cost, which occurs as the well
becomes older, due to the increased water to be handled, wear on ma-

25000-

Salvnrfe

20000.

1 15000.

UlQQDO-

*~*

,--

^^ -

,. f

~ ^~"~~~~~~-^

5000

-^**

""" "~ "" """^ ^T~^^^-^

Dollars

""^^^ "^^^

5000 -

\ 10000-

15000-

20000-

25000-
80000-

6 12 18 24 30 30

Months

FIG. 2. HYPOTHETICAL LEASE STATUS-TIME, OR DOLLARS-TIME, CURVE OP LEASE

CONTAINING WELL A.

chinery, etc. So that while the well may be profitably operated for 100
bbl. per day, it cannot be profitably operated for 5 bbl. per day.

According to the hypothetical lease status-time curve, though well
B was depleted more rapidly than well A, it was the more profitable well

ARTHUR KNAPP

407

at the end of the sixteenth month. It cost less to drill and the difference
between income and investment was greater after the well was completed.
This curve had not reached the apex at the end of the sixteenth month,
although the well was producing only one-half the quantity of oil pro-
duced by well A so that well B could have been profitably operated until
the seventeenth or eighteenth month. The flatter curve of well B maybe

100000
80000

GOOOO

20000
10000

5000-

Dc liars.

10000-

Solvage

If Salvage

-Max. Probable Price
of Oil

1 Year 2 Years 3 Years

FIG. 3. TYPICAL CURVE OF LONG-LIVED WELL FOB GULF COAST FIELD.

due to the fact that the operating expenses were uniformly lower than
those of well A because they were shared by several properties, while well
A was so far from other production as to necessitate its being operated
by itself. A difference in the amount of salt water handled would influ-
ence the curve.

25000-

20000-

15000-

J^OBB if rig t renewed in

10000-

- 1

Profit If rig is renewed ID

5000-

10th month

Drill A

5000-

10000-

15000-

20000-
25000-

30000-

2 4 6 8 10 12 14 18 18

FIG. 4. DOLLARS-TIME CURVE.

As stated, these curves are hypothetical. Few wells would show a
profit for one month and a sufficient loss the next month to' warrant
abandoning the well. In a great many cases, the apex of the curve is
flat and a small profit will be shown for a period extending from several
months to several years. In order to show the method to be followed,
the simplest case has been taken.

OTHER USES OF LEASE STATUS-TIME CURVES

Depreciation of the derricks, pumping rigs, and machinery do not
materially affect the lease status-time curves of short-lived wells. If,

408

MODIFIED OIL-WELL DEPLETION CURVES

however, the wells are long lived the salvage value may determine the
point at which wells may be profitably pulled. Fig. 3 shows a typical
curve of a long-lived well for the Gulf Coast field. This well shows a
good profit up to the end of the second year. During the third year
there will be a small profit but the curve shows that the salvage value at
the end of the second year is greater than the probable salvage value at
the end of the third year plus the probable profit for the year. It would,
therefore, be more profitable to abandon the lease at the end_of the
second year than to operate during the third.

In attempting to analyze such curves for as long a period as a year
account must be taken of the probability of a fluctuation in the price of

1 ! ,

I I

* 2

Time

FIG. 5.

oil. Fig. 3 shows that even taking into account the maximum probable
increase in the price of oil the maximum profit from this lease will be
obtained by pulling the wells at the end of the second year. If consider-
able repairs are necessary this form of curve is valuable for deciding
whether or not the investment is warranted.

The recovery value of wells A and B added to Fig. 1 show that while
well 'B showed a greater profit than well A when both reached the
apex of their curves, the final profit from each well was the same, as the
salvage from well A was greater than that from well B.

In the case of accidents, such as fire, it is hard to determine whether
or not the investment in new rigs and machinery will be profitable. With
the dollars-time curve, as shown in Fig. 4, this question may be decided
with some degree of accuracy. If the fire occurred in the tenth month

ARTHUR KNAPP 409

and the renewal was estimated at $5000, transposing the probable lease
status curve shows that the additional investment is warranted, for the
apex of the curve finally rises above the point at which the fire occurred.
If, however, the fire occurred in the fourteenth, the curve will not rise
above the profit shown at the time of the accident, which means that it
would not be profitable to renew the machinery.

LEASES WITH MORE THAN ONE WELL

While the majority of leases have more than one well and the several
wells are not all drilled at one time, this does not affect the curve after
the drilling program is complete and the production is settled. While
drilling the second and subsequent wells the lease status curve may run

10 12 14 16
Months

FIG. 6. LEASE STATUS-TIME CURVE FROM A PROPERTY IN PINE ISLAND, LA.,
DISTRICT. RECORDS NOT AVAILABLE PREVIOUS TO FOURTH MONTH. NINE WELLS
DRILLED ON 160-ACRE LEASE BETWEEN FOURTH AND NINTH MONTH. DECREASE IN
PRODUCTION AND INCREASE IN AMOUNT OF SALT WATER WAS SO RAPID THAT FOUR
MONTHS AFTER DRILLING PROGRAM WAS COMPLETE THE LEASE CEASED TO BE PROFIT-
ABLE WITHOUT HAVING PAID OUT. AN INCREASE IN PRICE OP OIL IN FIFTEENTH
MONTH SERVED TO CHECK THE LOSS BUT DID NOT TURN IT INTO A PROFIT. CURVE
SHOWS CONCLUSIVELY THAT REGARDLESS OF AMOUNT OF PRODUCTION OR AGE OP
WELLS, THE LEASE SHOULD BE ABANDONED. INSERT SHOWS DEPLETION CURVE OP
LEASE. PREVIOUS TO TWELFTH MONTH, NO GAGE OF DAILY PRODUCTION COULD BE
TAKEN, AS WELLS PRODUCED INTO EARTHEN STORAGE.

nearly horizontally, the income from production of the wells drilled off-
setting the cost of wells drilling. When all the wells on a lease are pump-
ing into the same tank and all of the wells have been drilled within a
reasonable length of time of one another, the depletion curve of the lease
is a fair gage of the depletion of each well.

PROPERTY VALUATION

The value of a property is its salvage value plus its probable earnings
up to the time it reached the point of maximum profit, interest, taxes,
and insurance. If the lease status-time curves have been properly and
accurately drawn, the value of any property maybe taken directly from its
curve. As interest, taxes, and insurance are constants, they do not affect
the shape of the curve and need not be included for ordinary analysis,

410

MODIFIED-OIL-WELL DEPLETION CURVES
VARIATIONS OF DATA

Variations in the systems of bookkeeping may produce slightly differ-
ent curves but they usually allow for the same analysis as outlined.
If interest and overhead are charged monthly to the expense of the lease
they make a more accurate curve but do not affect the shape. If depre-
ciation is charged off yearly against the lease, it should be prorated
monthly at the end of ,the year and the lease status curve redrawn.

Lease operating at a loss due to some
sudden change in condition
of wells or lease

Dollars

Salvage

(Accrued Profit )

(Accrued Loss)

24 6 8 10 12 14 15 18

Months

FIG. 7. END OP A LEASE STATUS-TIME CURVE is GIVEN ABOVE. IF CAREFUL

ATTENTION HAD BEEN PAID TO STATUS OF LEASE, IT WOULD NOT HAVE BEEN OPERATED
AT A^LOSS FOR SO LONG A TIME.

Dollars

(Accrued Profit^

(Accrued Loss

12 14
Months

FIG. 8. A. LEASE WAS BEING OPERATED AT GOOD PROFIT UNTIL SALT WATER

BROKE IN AND RUINED ONE OF THE WELLS.

B. ADVANCE IN PRICE OF OIL CHANGED A SMALL LOSS INTO A SMALL PROFIT.

C. LEASE WAS OPERATED FOR NINE MONTHS AT TOTAL PROFIT OF $48. DEPRECIA-
TION ON MACHINERY WOULD MORE THAN OFFSET THIS.

The easier way, provided the bookkeeping system will allow, is to charge
the total investment against the lease and credit the salvage to the lease
when the operation is stopped.

EXAMPLES FROM PRACTICE

The curves shown in Figs. 6, 7, and 8 are taken from data of actual
operations. In one case, the full curve is given and in the rest just
enough of the curve is shown to illustrate the point desired. The values
of the dollar ordinate have not been given, the various curves having
been reduced to the same size as various scales on the dollar ordinate
would be confusing.

DISCUSSION 411

DISCUSSION

ROSWELL H. JOHNSON,* Pittsburgh, Pa. The curve suggested differs
from many other curves in being what might be called synthetic; it
shows in one line the net result of several items to get the result in which
the executive is particularly interested. Another feature is that it is
simply calculated, so that it can be made cheaply. If the executive
does not care about graphs, the same data in tabular form can be a
guide. The graph should carry the numerical data on the sheet for the
use of the executive.

It would be a mistake for the executive to feel that all the information
he needs is in this one graph. He should also watch graphs showing his
cost per well for maintenance, in order to check the relative efficiency
on his leases and personnel; he should also keep a graph on decline but
the ordinary decline curve is not helpful in old-age wells. The slope of
the decline on an old-age well does not show up fine differences at all
easily so that a graph showing the proportion of one year to the previous
year (persistence factor) will show readily the changes in his rate of
decline.

* Professor of Oil and Gas Production, University of Pittsburgh.

412 BARREL-DAY VALUES

Barrel-day Values

BY GLENN H. ALVEY AND ALDEN W. FOSTER, PITTSBURGH, PA.
(New York Meeting, February, 1921)

THE measure of value of an oil property is approximated by the length
of time it takes to "pay out;" viz., the time required for it to return the
original investment. This time varies in different fields. In the Appa-
lachian and Mid-Continent fields, a good investment pays out in about
four years; in California, it requires a slightly longer time; and in the Gulf
field about two years.

The two principal methods for establishing these values are based
on acreage, as in California, and on production, as in the Appalachian
field. The method of establishing values based on production 1 was
worked out in the Appalachian fields and approximates the value re-
markably well in some fields; but it is a rule of thumb and should be
used intelligently. Briefly, the method is as follows: An arbitrary num-
ber of dollars (called the barrel-day price) multiplied by the number of
barrels of settled daily production of the property gives the value. In
its crudest application, the barrel-day price is determined by the "$10 to
$0.01" rule, which means that the barrel-day price is one thousand times
the prevailing price of oil. For instance, with oil at $3.50 per bbl. the
barrel-day price would be $3500 per bbl. This rule, however, is not
strictly applied, for the barrel price is varied according to whether or
not the wells "hold up." But when a barrel price for a district has been
fixed it is quite general to raise or lower the price with the fluctuation in
the price of oil; here the "$10 to $0.01 "rule is used extensively. However,
the prospective purchaser takes into account tangible equipment upon
the property, the extent to which the drilling program has been carried
out, whether or not the wells are "shot" or natural, depth of wells, spacing
of wells, paraffin trouble, etc.

The basis of this method is settled production. As soon as production
is considered settled, a flat barrel-day price is generally applied to all
properties, no matter what their age. If it were possible to show that
this flat rate was erroneous and that the value of the property depended
on the point on the decline curve at which the wells happened to be (in
other words, their age), and also on the operating costs, the future price

1 Acknowledgment is due to Roswell H. Johnson, at whose suggestion this problem
was undertaken.

GLENN H. ALVEY AND ALDEN W. FOSTER

413

of oil, and the discounted value of the dollar, the buyer who recognized
these facts and bought accordingly (also observing depth and spacing
of wells, etc.) would be in an advantageous position; and the seller (al-
though he does not usually have sufficient data at hand to make a com-
plete appraisal) would be able to know when to sell his property to the
best advantage.

It is the purpose of this paper to show that there is a best time to buy
or sell production; in other words, that the value of property varies with a
number of complex factors, most of which may be used in making an analytic
appraisal of a property. To demonstrate the possibility of doing this,
two problems are presented:

First. In a given pool, one well was brought in May 1, 1920,
one was one year old on that date, another two years old, still another

5 3
aT
2

h
tt

S 14

S 12
11

5 8
^ 7

"". 6

A 5
> 4
& 3
2 2

*~^~-

*->*^

t ^

*^>.

1 2 3 4 5 7 8 9 10 11 12 13 14 15 16 " 1 2 34 56 18 910 15 20 25 3C
Years Sears

FIG. 1. FIG. 2.

FIG. 1. BARREL-DAY VALUES AND CURRENT BARREL-DAY PRICES FOR MAY 1, 1920,
FOR AVERAGE WELLS OF DIFFERENT AGES IN CAMERON DISTRICT, PA.

FIG. 2. BARREL-DAY VALUES AND CURRENT BARREL-DAY PRICES, ASSUMING THAT
WELL CAME IN WITH OIL AT $6 PER BARREL, FOR DIFFERENT YEARS IN LIFE OF

AVERAGE WELL IN CAMERON DISTRICT, PA.

was three years old, and so on. Which of these wells is it best to buy,
the one that just came in, one four years old, or one seven years old?

Second. To get the best return of the money invested, should a well
that comes in on May 1, 1920, be purchased on that date, or two years
from that date, or some years later?

For the first problem, the barrel-day value of an average well was
determined on the assumption that it came in May 1, 1920; also, the
barrel-day value as of May 1, 1920 if the well had come in a year prior
to that date, two years prior to that date, and so forth, until a sufficient
number of years prior to make it ready for abandonment on May 1, 1920,
had been considered. These barrel-day values were plotted and curves
drawn. Similarly, for the second problem, analytical appraisals were

414 BARBEL-DAT VALUES

made for each year in the life of an average well, assuming that the well
came in May 1, 1920. That these values are different from those of the
preceding problem is due to the advancing price of oil. In the first case,
each appraisal starts with the price on May 1, 1920; in the second case
advanced prices of oil were used. In working out these appraisals, the
following form was used:

TABLE 1

NET PBICB w COMPOUND

VU-AR YEARLY PER GROSS INCOME rv>, = NET YEARLY DISCOUNT DISCOUNTED
BAB PRODUC- BAR- FOR YEAR yl^ INCOME FACTOR INCOME

TION REL 714 PER

CENT.

ABC BXC = D E D-E=F G F X G = H

1
2
3
4

n (7) Total

Economic limit
/ = salvage,

K = compound discount factor for n years,
J X K = L = discounted salvage,
/ + L = present worth,
M = daily production at beginning of year,
L -5- M = barrel-day value.

These values were worked out for the Cameron district, Pennsyl-
vania, of the Appalachian field, and the Osage Nation of theMid -Continent
field. The production data used in the former case were secured from a
company operating in that district; in the latter case, from BeaFs Decline
Curve. 1 An advancing price of oil was predicted; 2 per cent, for the
Cameron district (which was chosen in order to give a constant advance
up to $10 during the life of the well), and 10 per cent, for the Osage until
the price reached $10 for the remaining years (which was taken so as to
accord more closely with the price predictions that are considered to be
correct for the Mid-Continent field). Costs were taken at $600 per year
for the Cameron district and $1 per well day for the Osage. A 7J^ per
cent, compound discount factor was used. The salvage value used for
the Cameron district was $2000, and for the Osage $1000 (see Table 2).

Fig. 1 shows the curve for wells at different ages in the Cameron
district; the barrel-day values are plotted against the ages of the wells.
According to this curve the highest barrel-day value is for a well five
years old ; this, therefore, would be the best well to buy because the present

U. S. Bureau of Mines Butt. 177, 108.

GLENN H. ALVEY AND ALDEN W. FOSTER

415

worth of the future production of this well, compared to its daily present
production, is the highest. The barrel-day values of older wells decrease
until those ages are reached at which the well is near abandonment, when
the barrel-day values rise sharply. This is because of the higher pres-
ent worth of the salvage (the salvage value is discounted less and less
with the advancing age of the well). It would be attractive to buy an
old well on the barrel-day rate because one can sell the salvage and make
a profit.

TABLE 2

DISTRICT

PRICE OF OIL AS OF
MAY 1, 1920

WELL COSTS
PER YEAR

COMPOUND

DISCOUNT

FACTOR,

PER CENT.

Cameron, Pa $6.00 with 2 per

cent, rise (yearly)

Osage, Okla,

$3.50 with 10 per
cent, rise up to $10
and then a flat rate
of $10.

$600.00

$365.00

SALVAGE

$2000.00

$1000.00

COMPOUND
DISCOUNT

FACTOR FOR
SALVAGE.

PER CENT.

Barrel-Day Value,
n Thousands of Dollars

1 2 3 4 5 6 7 8 9 10 12 14 16
Years

J.O

15
I 14

312

5 u
sio

1 9

a 8

3 6

3
5 2

<~s-"

( (

"012S 6 9 12 15 18 21 24 27 30 33 36 39 42 46

Years

FIG. 4.

FIG. 3.

FIG. 3. BARREL-DAY VALUES FOR AVERAGE WELLS OP DIFFERENT AGES IN EASTERN
PART OF OSAGE INDIAN RESERVATION, OKLA.

FIG. 4. BARREL-DAY VALUES FOR DIFFERENT YEARS IN LIFE OF AVERAGE WELL IN
EASTERN PART OF OsAGE INDIAN RESERVATION, OKLA.

Fig. 2 shows the changes on barrel-day values for different periods
in the life of a single well in the Cameron district. According to this
curve, the best time to buy is six years from the date the well was brought
in, for then the well has its highest barrel-day value.

Figs. 3 and 4 are similar to Figs. 1 and 2, respectively, but are
for the Osage district. The most interesting fact is that the highest
barrel-day values come much later than for Cameron. This is due to a

416 BARBEL-DAY VALUES

flatter decline curve and a steeper predicted price curve. The significance
of this is that no generalization can be drawn for the best year to buy that
will apply to all pools. It must be worked out for each pool and the
year determined will be influenced by the price of oil predicted by the
appraiser.

CONCLUSIONS

The barrel-day value for settled production is not flat, as is generally
supposed, but from completion, increases with the age of a well up to the
maximum and then decreases; it increases again when the salvage value
becomes attractive.

There is a method by which the age at which a well has the highest
barrel-day value can be determined.

This age varies with the different pools and is due to five causes: the
decline curve of the pool, future price of oil, well costs, compound
discount factor, and salvage value.

DISCUSSION

ROSWELL H. JOHNSON,* Pittsburgh, Pa. The belief that one may
appraise on a flat barrel-day value is one of the most dangerous blunders
in the oil business. It is properly merely a method of expressing prices.
Some appraisers start with it as a basis and then work plus and minus
from it. Such a procedure is crude and objectionable.

These curves of Alvey and Foster show characteristically three
stages. In the first stage the decline rate is the dominant factor, and
throughout it the unit value advances; the rapid increase in unit value
is the outstanding characteristic. The one exception is where we have
wells that are very short-lived, such as some Ranger and Gulf Coast
wells, where it is quite possible that the second year would show a poorer
value than the first, because the whole thing has been shortened and the
year unit is too large a unit for such a curve.

The next stage is where the cost is the dominant factor; the rate of
decline is less weighty and the cost is steadily becoming a more important
factor.

The third stage is dominated by the foreshadowing of the salvage due
and represents the final up turn at the end. A curve, such as is made
here, can be constructed without salvage value, treating the salvage
value as a separate unit; but it seems best to put in the salvage value
consideration.

In Table 1 is the best working formula for oil appraisal that has
yet appeared in literature. In column E, well costs are handled by the
year, after yearly production has been multiplied by the price per barrel.
That is the place to take out the cost, because if taken earlier it will be

* Professor of Oil and Gas Production, University of Pittsburgh.

DISCUSSION 417

taken out on the barrel basis, which is so variable as it depends on pro-
duction. Costs then ought to be taken out on the basis of the well cost,
not the barrel cost. This formula puts in discounted salvage, which
feature has not always been recognized.

The formula makes obsolete the time-to-pay-out and the acre-yield
methods, in their usual forms except for the most rapid work. Both
suffer so severely by their non-recognition of the time element of
compound discount, that they are fallacious. It is surprising to note,
for instance, that in a long-lived curve, such as Salt Creek, the com-
pound discount, if one takes it at 10 per cent, cuts down the value to
only 45 per cent of the uncorrected acre-yield value. With such an
enormous range as that, the danger of acre-yield methods is seen.

The time-to-pay-out methods are so crude, in that they ignore the
shape of the curve after the well is paid out, that they cannot be con-
sidered. Acre-yield and time-to-pay-out methods can be used for quick
appraisal, however, if one works a series of annual analytic values and
uses these values to set up tables using various assumptions.

Another feature of this paper that demands attention is the method
of predicting a price advance. It is here taken on a percentage basis to a
plateau, and then flattened. This is better than the method of fixed
advance in cents per barrel; because, first, the price of different grades
of crude do not fluctuate with fixed differentials in cents, but by percent-
age of the highest grade although these percentages are not absolutely
fixed. For instance, all of us have been looking at these recent cuts in
prices. We noticed that Kansas-Oklahoma oil- was cut 50 per cent.,
and so predicted a drop in Pennsylvania of 50 per cent.; and we knew
before the last cut that there was another cut due, and still another
is due.

Furthermore, the theory of making price advance based on the fixed
amount per barrel, would have to be dependent on the thought that as
the price rises the demand is shortened. But in the case of oil and gas we
have some peculiar conditions. There is a nearly constant expansion
of the market for oil. We have oil going into new things the tractor,
the motor boat, the Deisel engine so that these larger needs postpone
saturation.

VOL. LXV. 27.

418 ISOSTATIC ADJUSTMENTS IN THEIR RELATION TO OIL DOMES

Isostatic Adjustments on a Minor Scale, in their
Relation to Oil Domes*

BY M. ALBERTSON,! E. M., SHREVBPORT, LA.

(New York Meeting, February, 1921)

AT Cobalt, Ontario, Canada, a lake was drained to facilitate mining,
by the Mining Corpn. of Canada, during the spring and early summer of
1915. Previous to pumping out the water, great quantities of sands and
slimes from concentrating plants had been discharged into the lake and
during and after the lake's drainage, its basin was a receptacle for tailing
products. As the writer was at work along the shore line as the lake was
being drained, he had a good opportunity to observe the changes that
took place as the water was withdrawn. Some adjustments between
the incoming sands and the mud in the lake had taken place before
pumping was commenced. One of the most interesting results was the
appearance of a small dome in a path the writer traversed twice a day for
several months; he remembers distinctly the difficulty of crossing this.

Cobalt Lake owed its existence to the gouging out of a rock basin by
glaciation. The long axis of the basin closely follows the strike of a
thrust fault of about 500 ft. (160 m.) vertical displacement. The lake
was originally shaped somewhat as shown. The length was about 3000
ft. (914.4 m.), the width at the lower lobe was about 1000 ft., and the
width at the narrows probably 400 to 500 ft. The original depth of
water varied from 20 to 30 ft. (6.1 to 9.1 m.), near where the island later
was formed, to 60 to 70 ft. (23.6 to 27.6 m.) in the widest part of the lower
lobe. At the narrows, the depth was 30 to 40 ft. Above the bed rock
was sand, with boulders near the bottom, and mud.

During the building of the railroad in 1903, considerable filling was
done along the right of way. With the commencement of mining opera-
tions, about 1905, waste rock and mill tailings were dumped into the
lake. One of the mining companies operated a hydraulic giant to remove
the glacial debris from several hundred acres of rock surface; much of
the sand and clay from this operation was deposited in the lake. About
1,500,000 tons of mill tailings, composed of sands and slimes, were dis-
charged into the lake's waters previous to 1915. Most of this material

*Published by permission of R. O. Conkling, chief geologist, Roxana Petroleum
Corpn.

t Geologist in charge Louisiana Division, Roxana Petroleum Corpn.

M. ALBERTSON

419

settled near the point of discharge but the fine slimes spread throughout
the lake basin Four artificial deltas were formed by tailings from
various concentrating mills, somewhat as shown along the upper end of
the lake.

The mud of the lake bottom was a thin black oozy slime, much too
thin to support a man's weight and too thick to swim in. Its specific
gravity was much less than that of the sands and slimes coming in;
probably it was not much greater than that of water. The incoming

FIG. 1. PLAN SHOWING LOCATION OF DOMES, ISLAND, TAILING PILES, ETC.

material pushed it aside in places and caused it to bow up as islands
and near islands in other places. The main part of the slimes from the
tailing discharge at 2, settling over the narrow part of the lake bottom,
strengthened the mud layer. Much of the mud from the upper end of
the lake was forced out toward the center of the upper lobe. After the
pumps had lowered the water level a few feet, an island a few hundred
feet in diameter appeared.

Small domes appeared near the shore at several points. After the
upper end of the lake was entirely drained, a large mud dome appeared in
about the middle of the narrows. It is perfectly clear that the weight of
the sands and slimes became too great to be supported by the thin oozy
mud and consequent buckling resulted in the formation of a dome.

The process of adjustments that brought the lake domes into exis-
tence is conceived to have gone on somewhat as follows: At the points

420 ISOSTATIC ADJUSTMENTS IN THEIR RELATION TO OIL DOMES

where the tailings were discharged into the lake, the mud, which was
less dense and in a jelly-like condition, was forced aside. Since the
tailings entered the upper basin of the lake from several well distributed
points along its shores the mud was forced toward the center of the lake.
At the same time a thin layer of fine sands and slimes was deposited over
the whole of the lake bottom, but chiefly near the shore and in a fan-like
arrangement from the points of tailing discharge. The effect of this was
to strengthen the mud layer near the shore and to weigh it down so
that the mud layer was weakest in the center of the lake. When the
weight of the sands became sufficient for the sand to displace the mud the
displacement occurred where the mud layer was weakest.

It is the writer's conclusion that domal structures have originated in
this manner in the Tertiary deposits of the Mississippi embayment re-
gion and that these structures of the Tertiary are, in many cases at least,
non-existent in the more compacted Cretaceous formations under them.
Thus a dome structure in surface formations does not necessarily mean a
dome in the Cretaceous oil-bearing sediments.

If this process is active in one region it must be considered as a struc-
tural factor in all areas of sedimentation. It is suggested as a factor in
the formation of certain domes observed in the Pennsylvanian area of
Missouri.

During 1911, 1912, and 1913, the writer, then a geologist for the
Missouri Bureau of Geology and Mines, became well acquainted with
minor dome structures that characterize the Pennsylvanian strata of
northern Missouri. Some of these domes are shown on a structural
map of Kansas City. 1 Many others are known in the coal mines of the
state. The origin of these domes has long been a puzzle. It is of course
possible that they are entirely the result of regional folding stresses, but
this view does not appear entirely logical.

1 McCourt, Albertson and Bennett: Missouri Bur. Geol. and Mines, Geology of
Jackson County (1917) 14 [2] PL xvi.

BIOGRAPHICAL NOTICE 421

Anthony F. Lucas

ANTHONY F. LUCAS died suddenly at his home in Washington, D. C.,
on Sept. 2, 1921. Captain Lucas, as he was known to us, was born in
Dalmatia, Austria, in 1855, of Montenegrin ancestry. He was graduated
as an engineer at the Polytechnic of Gratz and served in the Austrian
Navy as second lieutenant. In 1879, he obtained leave of absence and
visited an uncle in the United States. After an extension of this leave of
absence, in order to undertake an engineering engagement in the lumber
district of Michigan, where he resided, he decided to become an American
citizen. He was naturalized in May, 1885.

His name was Luchich, but as his uncle had adopted the name of
Lucas, which was more easily pronounced by Americans, from his
entrance to this country, he used this Anglo-Saxon form. Without
knowing this fact, upon first meeting him a person was sometimes sur-
prised to note the rather Germanic pronunciation of the Captain.

Although he subsequently revisited Austria with Mrs. Lucas, he made
his permanent home at Washington, D. C. His son served with distinc-
tion in the A. E. F. during the World War.

His activities in this country as a mining engineer were at first in
Colorado and later in salt mining at Petit Anse and Belle Isle, La. During
his salt investigations, his attention was directed toward the possibility
of oil in the Gulf Coast region and in January, 1901, his well, the "Lucas
Gusher," on Spindle Top, Tex., started a new era in the oil business and
his reputation as discoverer made him famous throughout the world.

Captain Lucas became a member of the A. I. M. E. in 1895. During
1914, 1915, 1918, and 1919, he was chairman of the Petroleum and Gas
Committee of the Institute and was at all times prominent in Institute
affairs.

As to the personality of Captain Lucas, the lasting impression is of a
courteous hospitable gentleman, genial, affable, obliging, and helpful with
his advice or assistance to any colleague. He was sincere, honest, firm
against all obstacles, backing his judgment with his own hard work along
any course which he had determined to be correct.

His value in the engineering world lies mainly in the petroleum indus-
try. In the oil business all wild-catters are pioneers that deserve credit
and gratitude upon their success. There are, however, names that par-
ticularly stand out in our history. Drake conquered such obstacles as
ridicule, lack of finances, and started the oil business. In 1901, Captain
Lucas had the conviction that Spindle Top, a dome rising about 12 ft.
above the coastal prairie south of Beaumont, Tex., contained commercial
oil. He was scoffed at by practical oil men of the East. Noted geologists

422 BIOGRAPHICAL NOTICE

were condemnatory on the ground that such an occurrence was unprece-
dented. It was a rank wildcat. Savage, Sharp, and others had tried to
drill wells, one at least, with cable tools, and had given up, but Captain
Lucas put down one well, which was ruined at about 600 ft., having had a
showing of heavy oil. Obtaining financial support, with the J. M. Guffey
Petroleum Co., he drilled another well to the depth of less than 1100 ft.
In January, 1901, this well came in at a rate estimated as high as 125,000
bbl. per day and flowed wild for ten days before it was finally controlled.

ANTHONY F. LUCAS.

The discoverer estimated the flow at 75,000 to 100,000 bbl., but the above
figure is an estimate of a civil engineer who gaged it by a full 6-in. stream
of oil 200 ft. high and what tests could be made of runoff of the oil. This
discovery astounded the oil men of the world.

It should be recalled that for the drilling of this well a rotary rig was
used; this method was then in its infancy (having been used only in Cor-
sicana and in some water-well drilling) so that the wild-catter had but
slight benefit of experience of others. He was obliged to devise his own

ANTHONY F. LOUCAS 423

methods of combating drilling difficulties, and in doing so earned rights
to patent, of which I do not believe he availed himself.

I quote here a question and answer published in the Mining and
Scientific Press (Dec. 22, 1917) :

T. A. RICKARD. I hope, Captain, that you received a proper financial reward
this time?

A. F. LUCAS. I did, but my chief reward was to have created a precedent in
geology whereby the Gulf Coast of the Coastal Plain has been and is now a beehive
of production and industry.

We would all have asked the question and must regret that, while his
later career was undoubtedly financially successful, at Damon Mound
and some other localities where our deceased fellow member wild-catted,
he was too far ahead of his time to make further successes. The answer
was characteristically sincere and intrinsically true. Old timers remem-
ber Beaumont, a small lumber town with mud streets, becoming a regular
beehive during 1901. We recall the forest of derricks with overlapping
legs on the 300-acre Spindle Top; the lakes of oil lying unused on "the
Hill" without proper transportation for removal; the hurly burly where
land was sold and paid for at the rate of one million dollars per acre; the
wild stock-selling schemes that filled the daily press. These are disagree-
able though interesting sides of the feverish and foolish oil stampede. On
the opposite and wonderful side, as a direct result of Captain Lucas'
perseverance, was the rise of legitimate operators to success; namely, the
J. M. Guffey Petroleum Co. (The Gulf Refining Co.) and The Texas Co.
Further development was stimulated at Sour Lake, Batson, Saratoga,
Humble; later, at Damon Mound, Goose Creek, Hull and other fields.

This all refers to the Gulf Coast, but why should Captain Lucas have
confined his influence to that region? There are today, in the Mid-Conti-
nent and other districts, veritable powers in oil production who had their
lessons on the derrick floors of Spindle Top rigs subsequent to the "Lucas
Gusher."

Along the scientific side, there has been much discussion of Coastal
Plain problems. By such free exchange of knowledge, advance has been
made toward the truth, not only as applicable to Texas and Louisiana
but to Oklahoma, California, and the East; to Mexico, South America,
and other foreign fields.

This is what Captain Lucas was after in starting his oil venture; this
is what we are after-^the truth. We owe his memory gratitude for
starting a new era in oil production twenty years ago, which has had
tremendous effect in the professional and business lives of all of us down
to the present time.

Although he considered himself "properly rewarded," we may believe
that even though he was beyond want, he was entitled to much greater
financial reward than he received. Certainly he deserves a prominent
and permanent place in oil history because of his Spindle Top discovery.

H. B. GOODKICH.

424 ROCK CLASSIFICATION FROM THE OIL-DRILLER'S STANDPOINT

Rock Classification from the Oil-driller's Standpoint

BY ARTHUR KNAPP, M. E., SHREVEPORT, LA.
(New York Meeting, February, 1920)

THE ordinary well log is subjected to a great deal of criticism, much
of which is well founded. Sometimes, though, the difficulty in interpret-
ing the log is due to the fact that the geologist or engineer using the logs
does not know the limitations of the drilling method used. The rotary
drill, especially, has inherent limitations that make it difficult to secure
definite information at all times. The identification of well-defined key
beds is about all that can be expected from the rotary log. The forma-
tion in a drilled hole, as reported by the driller, has a direct relation to the
speed with which the drill makes the hole or to the reaction of the various
strata on the bit, called the "feel of the bit. " When this is not thoroughly
understood by the geologist or engineer endeavoring to interpret the log,
the result is an erroneous correlation with other wells or a discarding of
the log as worthless.

GENERAL TERMS

Hard and Soft. Hard and soft are relative terms. In the case of well
logs, they are very misleading as they are used in connection with both
resistance to abrasion and resistance to percussion. In technical rock
classification, hardness is relative resistance to abrasion. The term
brittleness is used in connection with resistance to blows. These terms
are misleading to the geologist or engineer who is not familiar with both
the cable-tool, or standard tool, method of drilling and the rotary method.
In the case of the standard tools, the driller's report of the hardness of the
formation is in terms of its resistance to blows. For instance, a cable-
tool driller might be able to make from 30 to 50 ft. a tour in a brittle
limestone, which he would call soft and at the same time he might call a
relatively soft (from a purely mineralogical standpoint) gypsum hard,
because it is somewhat elastic and is not readily broken by blows. The
rotary driller would reverse the terms. The limestone is hard in that it
resists the abrasive action of the bit, while the gypsum might be soft in
that it is readily cut by the rotary bit. It is rare that wells drilled by the
standard tools are correlated with those drilled by the rotary, but the
technologist who has worked with well logs from one system might be
misled when working with the other.

ARTHUR KNAPP 425

Sticky. With the rotary drill, a formation is sticky which cuts in
large pieces that adhere to the bit and drill pipe. A formation that is
sticky with the rotary is usually sticky with the cable tools. On the
other hand, formations are encountered in which the cable tools stick,
either owing to the elasticity of the formation or to the fact that the
drilled-up particles do not mix readily with the water in the hole and settle
so quickly as to stick the bit. These formations might not appear
sticky to the rotary driller.

Sandy. This term may be used quite accurately by the cable-tool
driller. He obtains samples of the formation through which he passes, of
sufficient size to determine the relative amount of sand to clay or sand
to shale in any formation. In the case of the rotary drill, this term is
misleading.

The rotary well is drilled with the aid of a "mud" of varying density
It is usually thought of as a mixture of clay and water with a small amount
of suspended sand. As a matter of fact this mud often contains as high
as 40 to 50 per cent. sand. This sand tends to destroy the col-
loidal properties of the mud and the action of the mud on the walls of
the well is the same as a thin mud with less fine sand. The water would
tend to exchange the suspended sand for mud from the walls of the well,
thus thinning the well wall. It is impossible to settle out the very fine
sand in any rotary mud. An easy and quick way to separate the two for
examination is to fill the glass of a centrifugal separator half full of mud
and add a saturated solution of common salt. The sand will be thrown
to the bottom when the machine is turned for a short time. The mud
alone can be turned indefinitely without any appreciable separation.

Any change in the density of the mud changes its capacity to carry
sand. Even a small shower falling on the slush pit will change the
density enough to cause some of the suspended sand to be precipitated.
These properties of the mud lead to error in the observation of the forma-
tion. If a clay formation containing a moderate amount of sand is
encountered while drilling in a mud low in sand content, the mud will
absorb most of the sand, which will not settle out in the overflow ditch
and its presence in the formation will not be noted, if not felt by the action
of the bit in drilling. If, some time later, the mud is thinned by adding
water this sand will appear in the overflow and may be attributed to a
formation many feet below the one from which it actually originated.

The so-called " jigging " action of the rising column of mud on the
sand or cuttings also leads to misinterpretation. I have often heard
drillers remark that the deeper you drill, the finer the sand. This is not
true, but it is true that the deeper you drill, the finer the sand or
cuttings brought to the surface by the mud. The coarser particles have
been pounded into the walls of the well or broken and the deeper the well,
the more opportunity the drill pipe has had to do this.

426 KOCK CLASSIFICATION FROM THE OIL-DRILLER'S STANDPOINT

A change in the speed of pumping the mud also causes a change in the
amount and size of the cuttings that appear at the surface. Thus, in the
case of the rotary, "sandy " may have little or no meaning when applied to a
formation. The term sandy is often used in contradistinction to sticky.
A formation that drills easily and is not sticky is often put down as sandy
because sand tends to interfere with the stickiness. Sand does not always
account for the lack of stickiness but the latter is often attributed to its
presence.

Dark and Light. This brings up the subject of color. The first
question is the age of the specimen when the color is determined. A wet
specimen, fresh from the hole, has an entirely different color from the
same specimen dried. Specimens, when dried, bleach and deteriorate.
Many of them air slack or oxidize and change composition altogether.
The terms light and dark should be used only for the extremes. They
are, in general, relative and therefore very indefinite and misleading.
A sample of wet shale examined under an electric light might appear
many shades darker than in day light. It is better to use a definite name
than the words light and dark ; such as slate-colored or chocolate-colored
shale. On the other hand, color is not very important except in key beds,
which are usually of extreme shades, either very light or very dark.

FORMATIONS

Clay, Gumbo, Tough Gumbo. Clay is readily recognized by the "feel
of the bit" while drilling with either cable tools or rotary. To some drill-
ers all clay is gumbo while to others gumbo is only sticky clay. Some
clays have the property of cutting in large pieces but do not adhere
excessively to the bit and drill pipe and are designated as "tough."

Sand, Packed Sand, Water Sand, Quicksand, Heaving Sand, Oil Sand,
Gas Sand. Free, uncemented sand is easily recognized by the feel of the
tools in both systems of drilling. In rotary territory, we often run across
the term "packed sand." This is a sand that is slightly cemented with
some soft easily broken cementing material, such as calcium carbonate.
It cuts, when drilled with a rotary, with much the same feeling as when
cutting crayon with a knife. The cementing material is dissolved by the
mud or the sand grains are all broken apart before reaching the surface,
so that the driller finds only sand in the overflow. A microscopic exami-
nation of sands from the overflow often shows cementing material to be
present when not suspected by the action of the bit.

Water sand is a sand containing water. There is no specific sand
associated with water; any porous formation may or may not contain
water. In the case of both rotary and cable tools, sand that is fresh and
bright and has a clean appearance when taken from the well impresses one
as being a water sand and probably does come from a wet stratum. If

AKTHTJR KNAPP 427

it so happens that the sand has been thoroughly mixed with the mud in
the hole so that each particle is colored by a film of mud, it does not appear
fresh and clean and does not give the impression of being a water sand.
This may be because the formation from which it came was dry or nearly
so or simply because conditions were right for the quick coloring of the
sand by the mud. Whether a given porous formation is a water stratum
or not can only be determined by testing. It is only in rare cases that
the hydrostatic pressure is sufficient to cause the thinning of the mud in a
rotary hole. While drilling in a dry hole with the cable tool, it is known
at once how prolific a porous stratum is.

A sand containing no cementing material nor clay very often caves
badly in the hole. If this sand settles with such rapidity as to threaten
to stick the tools, it is designated quicksand. Such a free sand may, on
the other hand, have such properties that it seems to tend to float. It
not only caves but fills the hole above its original horizon, sometimes
heaving clear to the surface. This sand is called a heaving sand. The
presence of gas or a high hydrostatic head often accounts for the heaving
of the sand.

An oil sand is a sand containing oil. There is no particular sand which
is associated with oil; any porous stratum might contain oil. A porous
stratum containing oil is often called a sand although it may actually
be a limestone.

A gas sand is any. sand containing gas; even a hard limestone is some-
tunes designated as a gas sand.

Boulders and Gravel. True boulder formations are rarely encountered
in drilling for oil. They are encountered above the Trenton in Ohio and
Indiana and occasionally in California. Concretions are often encoun-
tered which fall into the hole and follow the bit for some time and are re-
ported as boulders. A green rotary driller will report boulders when he
is drilling in sticky gumbo, which causes the bit to jump excessively.

Gravel is also quite rare and as it is a question what is coarse sand and
what is gravel, a report of gravel may mean coarse sand. The cable
tools will bring up gravel so that it may be recognized. Loose shale or
oyster shells may be reported as gravel by the rotary driller.

Shale. Shale, to many drillers, is only that kind of true shale which
appears in the overflow, or bailer, in flakes, that is, laminated shale with
well-defined bedding. Other drillers include formations that are sedimen-
tary in character and are consolidated enough to appear in the overflow,
or bailer, in pieces as large as a pea or larger. They usually call a shale
too hard to scratch with the finger nail rock, particularly in rotary terri-
tory. The rotary driller finds it hard to differentiate between hard shale
and soft limestone.

428 ROCK CLASSIFICATION FROM THE OIL-DRILLER'S STANDPOINT

II 1 1

Ull

is s s

HM-

1I.IHI

-. lg i.

till!
in-

iiiji;ii n !as
u|8i 8 a aa s&&

a i
I i

o o

o *1l ! 1 8 I -a

||| ||| j|

S S

03 2
J3

. ^

I* 'i

! I 1

^2 S o

-I 1

t3"T3

19
^

.3 60 a

-s^-a

11314

HIM!

li^l
1! I i

aw o o

s"8

ARTHUR KNAPP 429

Rock, Gas Rock, Chalk Rock, Sand Rock, Sandstone, Shell, Shell Rock,
Flinty Rock, Limestone, Lignite.- When the rotary driller strikes any-
thing hard and does not know what it is, he puts down rock. If this
hard substance is a concretion near the surface, it is a rock just the same
as the most consolidated formations deeper down. The cable-tool driller
has a much better general knowledge and a much better chance to get
samples and hunts for some name to apply to the formation.

A gas rock is any rock formation containing gas; the term is applied
to both sandstone and limestone,

Chalk rock is usually readily recognized by both rotary and cable-
tool drillers. It is usually white or very light in color and quickly
changes the rotary mud from its usual dark gray to almost white.

Sand rock, or sandstone, is usually recognized by the rotary driller,
except when it is so soft as to be classified as packed sand. The harder
formations appear in the overflow in pieces sufficiently large to be readily
recognized. The cable-tool driller is able to recognize sandstone and all
other hard formations as he finds large fragments in the bailer.

Shell is a very misleading term. If a driller, either rotary or cable-
tool, drills from a soft formation into a hard one he gives it what he con-
siders its proper name. If, however, after drilling for a short distance,
he goes back into a soft formation again he is liable to put down shell.
This shell may be from a few inches to a foot or two in thickness, it means
a thin layer or shell of rock.

Shell rock means a rock formation containing fossil shells, unless the
driller is very careless or misunderstands the term shell, in which case
he may put down shell rock, meaning a thin shell of rock.

Most cable-tool drillers are able to distinguish the characteristic
fracture of flint and their report of flint or flinty rock may usually be re-
lied on. Flint is very seldom encountered with the rotary and when
reported in a structure in which it is not likely to be found is probably
used to designate a very brittle limestone, flinty in character.

The cable-tool driller's report of limestone is usually correct but the
rotary driller does not always distinguish between hard shale and limestone.

Lignite is used to designate both the petrified and the bituminous
forms of wood found in drilling. Even when the wood has not lost its
fibrous character, it is often designated as lignite.

Shells. In rare instances, solid beds of shells are encountered. They
are easily recognized as such with the cable tools but with the rotary they
may not be recognized and may be reported as sand or gravel, depending
on the feel of the bit while drilling. When mixed with clay or sand,
shells usually appear in the log as, "sand with shells " or " clay with shells."

430 INVESTIGATIONS CONCERNING OIL-WATER EMULSION

Investigations Concerning Oil-water Emulsion*

BY ALEX. W. Me COY, BARTLESVILLE, OKLA., H. R. SHIDEL, EL DORADO, KANS.,
AND E. A TRACER, BARTLESVILLE, OKLA.

(Chicago Meeting, September, 1919)

SAMPLING of the fluid from oil wells for percentages of oil, emulsified
oil, and water during the last two years has brought out some interesting
facts concerning oil-water emulsion. This result led to a laboratory
investigation of emulsion, which substantiated the conclusions made from
the field observations. The purpose of this paper is to present the infor-
mation collected, the laboratory experiments, and our interpretation of
the same. In order to define emulsified oil exactly, give its synthesis and
origin, and to show how and when it is formed in the wells, the work was
necessarily divided into two separate lines laboratory work and field
observations. It is hoped that this study may lead to a discussion of such
points so that the petroleum engineer, geologist, or technologist may be
benefited by its practical bearing on oil-field management. Special
credit is due Mr. Everett Carpenter, chief geologist of the Empire Gas
& Fuel Co., for his assistance and cooperation in this work.

LABORATORY INVESTIGATIONS ON EMULSIFIED OIL

Laboratory investigations were conducted in an attempt to learn the
composition and some of the properties of emulsified oil, or B. S., as it is
more commonly called, also to demonstrate, by laboratory methods,
how B. S. may be formed under conditions similar to those existing
at the time a well is being pumped, and how it may be broken down.
Literature bearing on this subject is widely scattered and very limited in
scope. Bacon and Hamor define B. S., or bottom settlings, as "earthy
matter, inert organic matter, or, in the case of Pennsylvanian petro-
leum, an emulsion of paraffin wax and water, which accompanies crude
oil." In this discussion we will limit the term B. S. to that heavy,
dark-brown emulsion, composed of a physical mixture of water, oil,
and air with some included inert matter, either organic or inorganic.

Possibly the first step in a description of this product should be a
description of its physical properties, but since most operators are quite

* Published through the courtesy of the Empire Gas & Fuel Co Read before the
Tulsa Section, February, 1919.

ALEX. W. MCCOY, H. R. SHIDEL AND E. A. TRACER 431

familiar with emulsified oil, and because the physical discussion will be
better understood after one is familiar with the microscopic studies, that
side of the investigation will be presented first.

A thin layer of emulsified oil under the microscope appears as a yellow-
ish to brownish green, solid mass of small bubbles, with an occasional
larger colorless bubble of water and smaller brownish globules of oil.
Fig. 1 shows this relation. All of the large and most of the small,
colorless bubbles are composed of water surrounded by an oil film. The
dark spots are bubbles of oil. The dark material surrounding and be-
tween the bubbles is oil. The few, very bright small bubbles are air.

Careful examination shows that permanently emulsified oil is com-
posed of millions of small bubbles of water that range in diameter from
0.004 to 0.020 mm., the most numerous having a diameter of about
0.016 mm. These bubbles are packed very closely together in a medium
of oil, the average distance between them being less than one-half their
diameter. Scattered in and among these very small bubbles is a rela-
tively small number of larger bubbles of water, which vary in diameter
from 0.034 to 0.070 mm. There is also about one-tenth this number of
still larger bubbles of water, which vary in diameter from 0.110 to 250
mm. It is about these larger sizes that the very smallest bubbles are
concentrated. There are a few bubbles of either water or air, with a
diameter of 0.004 mm., scattered among the "groundmass" of small
bubbles, which are about 0.016 mm. in diameter; but there are many
very small ones located in the oil film that envelops the large water
bubbles. This arrangement can be clearly seen by noticing the large
bubbles of water in Fig. 1. Nearly all of the small bubbles are filled with
water; a few contain air. If the material is heated very slightly, the
small bubbles begin a more or less constant motion toward and away from
the larger bubbles. The motion is eddying in nature and becomes more
rapid as the heat is increased. Occasionally one of the small bubbles
drifts away from the current that causes it to move about the larger
bubble and moves along the oil passage between the water bubbles of the
"groundmass," finally attaching itself to some large bubble.

There are also small globules, or isolated patches of oil, 0.003 to
0.050 mm. in diameter, trapped among the water bubbles. Some of these
are perfectly spherical in outline while others have no definite shape.
These globules of oil are usually composed of oil free from foreign matter
and appear dark reddish brown in color. Some of these may also be seen
in Fig. 1.

Air bubbles of any considerable size, that is, over 0.020 mm. in diame-
ter, are rarely found in emulsified oil that has stood for any length of
time. This is probably due to the fact that the films surrounding the air,
after they reach this size, are easily broken either by mechanical agita-
tion of the mass or by expansion of the air due to heating. The air

432

INVESTIGATIONS CONCERNING OIL-WATER EMULSION

bubbles are surrounded by a layer or film of oil, a film of water, and a
second film of oil. Fig. 2 shows the oil film on the outside of an air bubble.
There appears to be a constant shifting or stretching of these films, which
is most easily seen- by watching the water film. The oil films appear to

FIG. 1. PHOTOMICROGRAPH OP TYPICAL B. s. x 450.

slide about or change their tension, causing streaks to develop in the
water film, which appear similar to convection currents or the streams of
water that move about on the surface of a soap bubble. Possibly this

FlG. 2. OlL FILM AROUND AN AIR
BUBBLE. X 450.

FIG. 3. WATER FILM BETWEEN THE OIL
FILMS OF AN AIR BUBBLE. X 450.

movement is caused by the heating due to the light from the condenser
or the microscope, for a large bubble of air seldom lasts over 5 min., in
the field of view, without breaking; or it may be due to evaporation of the
lighter constituents in the outer oil film, since such bubbles can only be

ALEX. W. MCCOY, H. E. SHIDEL AND E. A. TRACER 433

studied by isolating them in a thin layer with the upper part of the bubble
exposed to the air. The large bubble shown in Fig. 3 was taken with the
water film in focus and will give some idea of the irregularities in this
film. The circular shadows visible are from small bubbles on the
opposite side of this bubble. ^

The purity of the oil that fills the spaces between the water bubbles
varies widely with different samples. In some cases the oil is practically
free from foreign matter, while in others it is very muddy in appearance.
The water bubbles, in a sample composed of dirty oil, do not have as
definite sizes as they do in samples that are comparatively free from dirt.

FlG. 4. B. S. CONTAINING HIGH PERCENTAGE OF FOREIGN MATTER. X 450.

Fig. 4 shows a sample containing much foreign matter. In general, it
was found that the samples that tend to be most permanent are those
in which the oil contains a large percentage of suspended matter; and
those samples that are easily broken down contain relatively clean oil.

DEFINITION OF -EMULSIFIED OIL

The appearance of emulsified oil, under the microscope, is so different
from that of good crude oil that the two would never be confused by
such an examination. Of course, there are gradations from crude oil
to emulsified oil. A sample of good oil, under the microscope, appears
much the same as it does in a cylinder, with the exception that the foreign
matter in suspension is visible and an occasional water bubble will be
seen. As the oil approaches emulsification, the water bubbles become

VOL. LXV. 28.

434 INVESTIGATIONS CONCERNING OIL-WATER EMULSION

closer and closer together, until finally they appear to be touching each
other, when examined with a low-power lens. Just when an oil ceases
to be crude oil and is to be classified as emulsified depends more on its
physical appearance and plastic properties than on characteristics re-
vealed by microscopic examination. It might be said that oil in which
the water bubbles are spaced closer together than their diameter should
be termed emulsified. This definition would fit most cases, but there
would be exceptions because of the importance of suspended matter in
forming emulsified oil. An emulsion, containing water bubbles with this
spacing, that has a low specific gravity and is free from suspended matter
might be sufficiently mobile to be turned into a pipeline run and the
entire run treated by a simple heating process. An emulsion having the

FlG. 5. B. S. FREE FROM FOREIGN FlG. 6. B. S. WITH HIGH PERCENTAGE

MATTER. OF FOREIGN MATTER.

same spacing of the water bubbles but composed of a heavier oil and
containing a considerable amount of suspended matter would be quite
viscous and could be treated only by the use of a complex steaming
plant. Or, the water bubbles might be twice as far apart and yet the
emulsified oil would be more viscous than the first sample, because of
the difference in the character of the oil and the amount of foreign
matter in suspension. These varying factors make it difficult to establish
a dividing line between crude oil and emulsified oil, based on microscopic
examination, although usually such an examination will reveal instantly
the degree of emulsification, by revealing the spacing of the water bubbles
and the amount of suspended matter present.

Figs. 5 to 9 will give some idea of the appearance of different types
of emulsified oil under the microscope. Fig. 5, shows a sample of per-
manent B. S. that is practically free from foreign matter. Fig. 6 shows
very heavy and dirty B. S. Fig. 7 shows B. S. that contains very little
suspended matter. In Fig. 8, the sample is only partly emulsified; the
group of small bubbles in the lower left-hand side marks the place where
a large air bubble broke just as the picture was being taken. Fig. 9
shows B. S. that is drying up and shows the coalescing of the water
bubbles, which causes the irregular shape of the large bubbles.

ALEX. W. MCCOY, H. R. SHIDEL AND E. A. TRAGEE 435

The surface tension of an oil-water contact makes it necessary for
the water bubbles to be very small in order to have permanent B. S.
If the water bubbles are large, say 1 mm. in diameter, the masses of
water in two such bubbles have sufficient attraction for each other and

FIG. 7. DIFFERENT SIZES OF .BUBBLES. X 200 .

FIG. 8. PARTLY EMULSIFIED OIL. X 450.

sufficient force, in case of an impact, to break the film of oil surrounding
them and thus make a larger water bubble. As this process repeats itself
and the bubbles increase in size, their weight will cause them to settle
through the B. S. until the water collects below the emulsion. Or an

436 INVESTIGATIONS CONCERNING OIL-WATER EMULSION

increase in the temperature may cause sufficient expansion to break
the oil film; if the bubble at this time is in contact with the container
or a water layer below the B. S., the water in the bubble will either
join that below it or will adhere to the container. If it remains attached
to the side of the container, the water from other large bubbles may
be added to it until the large bubble so formed settles to the bottom.

In the case of very small water bubbles, the force of attraction upon
impact is not sufficient for the water to break the oil film, neither will
an increase in the temperature cause sufficient expansion to rupture this
film. It is a simple matter to join two large water bubbles together by
puncturing the oil films surrounding them with a needle; but it is prac-
tically impossible to join two small water bubbles, say 0.005 mm. in

FIG. 9. PHOTOMICROGRAPH OF B. s. WHILE DRYING. X 450.

diameter, by any amount of patience or skill. Such small bubbles may
be subjected to rather violent impacts and the tendency is to break
into even smaller bubbles, rather than to coalesce.

In a recent article by Harkins, Davies, and Clark, 1 it is stated that
"for the emulsoid particle 'to be stable, the molecules which make the
transition from the interior of the drop to the dispersion medium, or the
molecules of the 'film' should fit the curvature of the drop. From this
standpoint, the surface tension of very small drops is a function of the
curvature of the surface." Their studies have suggested that small
drops in an emulsion tend to be stable only when the size of the drop is
such that the molecules in the surface film fit the curvature of the sur-

1 W. D. Harkins, E. C. H. Davies, G. L. Clark : Orientation of Molecules in the Sur-
faces of Liquids, etc. Jnl. Amer. Chem. Soc. (April, 1917) 39, 541-596.

ALEX. W. MCCOY; H. R. SHIDEL AND E. A. TRAGER 437

face. There may be more than one size of bubble in which the number
of molecules in the surface fit the curvature of the drop. This tendency
for the water bubbles in B. S. to arrange themselves in definite sizes is
clearly seen in Figs. 1, 3, 7, and 8.

PHYSICO-CHEMICAL PROPERTIES OF EMULSIFIED OIL

The physico-chemical properties of emulsified oil are quite variable,
and each sample is more or less of an individual problem. The color
that is most common is a dark, reddish brown, although any color from
yellowish or greenish to gray or nearly black may be found. The darker
colors generally contain more suspended matter.

CLASSES OF EMULSIFIED OIL

The permanency of emulsified oil may be used as a basis for divi-
sion into two classes: Temporarily emulsified oil and permanently emul-
sified oil. The two classes cannot be separated by their appearance.
This fact was brought out by two sets of samples sent to the laboratory.
When the first set was opened, the glass jars appeared to contain about
one-third water and two-thirds crude oil. The sampler's attention was
called to this fact, but he insisted that the samples were "the best look-
ing B. S." he had ever seen. A second set came at a later date and about
half of these had no microscopic resemblance to B. S. when they reached
the laboratory. The oil from these samples was examined under the
microscope, and it was found that there were water bubbles present, but
they were spaced about ten to twenty times their diameter apart. There
were practically no very small water bubbles present, which indicates
that this material was not subjected to as violent treatment as is the
case with permanent B. S. Investigations in the laboratory demon-
strated that oil emulsified by a minimum amount of agitation will mostly
settle out in from one to three days. Of course there will be small
water bubbles present in the apparently good crude oil remaining, but
the percentage will be low.

Permanently Emulsified Oil

Permanently emulsified oil will stand indefinitely and the amount
of settling out is negligible. This oil is somewhat more viscous than
"fresh" temporarily emulsified oil, and does not contain as many large
globules of water, but otherwise the oils appear similar to the unaided
eye. The specific gravity of emulsified oil falls within rather narrow
limits, 0.95 to 0.995, although the average is about 0.96 (15.8 B6).
The oil that separated from temporarily emulsified oil from Augusta
had an average specific gravity of 0.86 (32. 8 Be). The specific gravity
of the Augusta crude oil used in the laboratory was 0.849 (34.0 Be).

438 INVESTIGATIONS CONCERNING OIL-WATER EMULSION

Permanently emulsified oil has a very high viscosity. At room tem-
peratures there are all gradations from a thick syrupy consistency to a
near-solid. In many samples a hydrometer placed upon the surface
will remain there indefinitely. Heat rapidly reduces this viscosity.
A sample of the most viscous oil, when heated to 122 F. (50 C.), will
readily drop from a glass rod. At 167 F. (75 C.), it has the consistency
of a thin syrup, and at or near its boiling point, about 190.4 F. (88 C.),
it is almost as mobile as water.

Groups of Permanently Emulsified Oil

In addition to lowering the viscosity, heat also divides permanent
B. S. into two groups. In the first group, the B. S. separates into water
and oil shortly after it has been heated to the boiling point, the change
taking place rather suddenly. Several degrees below the boiling point
there is no apparent change in the appearance of the sample, but as soon
as this temperature is reached the water settles rapidly.

Samples belonging to the second group may be heated to 221 F.
(105 C.) and held at this temperature until all the water and part of the
oil have been distilled over, and at no time will there be any signs of
separation of the oil and water in the still. However, in some of the
samples the water and oil did separate, on standing from 24 to 48 hr.,
after being heated for 1 hr. at 221 F. To heat above this temperature
in an open vessel is impossible under ordinary conditions, for the material
begins to froth and boil vigorously between 221 F. and 230 F.

The size and number of the water bubbles in these two groups of B. S.
is approximately the same, but just what is the cause of this marked
difference in behavior is not fully understood. However, the gravity
of the oil from which the B. S. was made, and the per cent, of foreign
material present, appear to be the factors that control this behavior.

AMOUNT OF WATER IN B. S.

It is the common belief among practical men in the Mid-Continent
field that B. S. may contain from 1 to 99 per cent, water. If an entire
pipeline run that contains water is all termed B. S., this statement may
be true; but if we limit B. S. to that emulsified product which is com-
monly recognized to be unfit for the refinery without a preliminary treat-
ment to remove the water, this statement is not true. On the other hand,
the per cent, of water in true B. S. is its most constant factor. In all
types of B. S., excepting temporary, the water content is very nearly 66
per cent. This fact was determined by distilling a number of samples
of B. S. from various sources, including samples that were manufactured
in the laboratory. An attempt was then made to synthesize B. S. in

ALEX. W. McCOY, H. R. SHIDEL AND E. A. TRACER

439

the laboratory, hoping to learn what are the controlling factors in its
formation, and more about its properties.

A 4-oz. oil-sample bottle completely filled with 70 per cent, water
and 30 per cent, oil 2 was rotated about a center, at right angles to its
length, at a speed of 900 r.p.m. for about 10 min.; at the end of this time
there were no signs of emulsification. The bottle was again rotated,
this time for 2J^ hr., but no emulsification took place. The bottle was

FIG. 10. SIMPLE APPARATUS IOR DEMONSTRATING EMULSIFICATION.

next placed on an automatic shaker and shaken for 3 hr., but no change
occurred. Part of the oil and water was then removed and about 10
per cent, of fine sand was placed in the bottle, which was rotated for 3
hr., and then shaken for 3 hr., but negative results were obtained as
before.

This experiment was repeated using 70 per cent, water and 30 per
cent, oil, but having the bottle only three-fourths full; hi just a few min-
utes after the bottle was placed upon the shaking device emulsification

2 Augusta crude oil was used in all laboratory experiments.

440 INVESTIGATIONS CONCERNING OIL-WATER EMULSION

began to take place. In 30 min. the entire contents of the bottle had
been converted into permanent B. S. These experiments indicate that
air or voids in the fluid, in addition to water and oil, are necessary in
the emulsification of oil, the air acting as a catalytic agent.

A simple laboratory apparatus for demonstrating emulsification,
under conditions more similar to those existing at the time a well is
being pumped, is shown in Fig. 10. One tube A passes into a beaker
containing oil, another tube B into a beaker of water, while air could be
introduced at will through a third C. The graduated cy Under is used
as a reservoir and the "well" is pumped by a vacuum attached to tube
D. Water and oil were first drawn through the column of sand; the
percentages of each were varied, but under no conditions was more than
1 per cent, of B. S. formed. But when water, oil, and ah* were drawn
through the sand, immediately the percentages of B. S. formed began to
rise. The "well" was pumped at different rates of speed and variable
amounts of air were introduced; the amount of B. S. formed ranged from
1 to 15 per cent.

If, instead of using fine sand, pebbles, about 0.25 in. (6.35 mm.) in
diameter or larger, are used and air under a low pressure is introduced
through a large opening, 0.1875 in. (4.7 mm.) diameter or larger, the
amount of B. S. formed will be very small. For under these conditions
most of the water and oil pass through the gravel without being broken
into bubbles small enough to remain permanently emulsified.

Since, to permanently emulsify oil, it is only necessary to break the
water present into very small bubbles and then surround these small
water bubbles with a film of oil before they have an opportunity to coa-
lesce, B. S. can be made by blowing air bubbles through water and oil
in a cylinder. If 67 c.c. of water and 23 c.c. of oil are placed in a 100 c.c.
graduated cylinder, and air, under 5 to 8 Ib. pressures coming from an
opening about 0.5 mm. in diameter, is allowed to bubble through the
column of liquid, the entire contents of the cylinder will be converted
into permanent B. S. within 3 to 5 min. The amount of B. S. formed,
up to a limiting per cent., will depend on the percentages of water and
oil present.

Table 1 gives the results of such an experiment, using various com-
binations of oil and water, and agitating for 5 min. with a current of air
under 5 Ib. pressure. The first readings were taken after standing for
30 min., the second after standing a week.

The settling out shown in the table is due mostly to large globules of
water trapped in the B. S. that later worked their way down through
the B. S. to the water level; and to small amounts of oil rising to the top
of the B. S. B. S. may also be made by this method if natural gas or
steam is substituted for the air.

ALEX. W. McCOY, H. K. SHIDEL AND E. A. TBAGER

441

TABLE 1. Percentage of B. S. Formed Upon Five-Minute Agitation,
Using Various Combinations of Oil and Water

Water, Per Cent.

Oil, Per Cent.

B. S. After Standing
30 Minutes, Per Cent.

B. S. After Standing One
Week, Per Cent.

100

Table 2 gives the distillation results from three samples of B. S.
No. 1 was taken at a well, No. 2 was received from a steaming plant, and
No. 3 is a composite of the samples obtained from the experiment shown hi
Table 1. In these experiments, the material was heated from 6 to 8 hr.
to obtain all the water. The residue is composed of all the oil boiling
over "105 C., fine particles of shale, sand, and limestone, and a few
crystals of salt and pyrite, flakes of mica, etc.

TABLE 2. Distillation Results

Number of Sample

Oil Distilling below
105 C. f * Per Cent.

Water, Per Cent.

Residue and Air,
Per Cent.

10.5

66.0

24.5

10.0

66.5

24.5

6.3

66.0

21.0

7 . air and loss.

* Distillation runs under 105 C. to determine the per cent, of water in B. S.

FIELD INVESTIGATION ON EMULSIFIED OIL

Oil accumulated at the bottom of a well enters the mechanical parts
through the perforated tubing. It is drawn, through the standing valve,
into the working barrel, when the ball is raised from its seat, by the
vacuum created in the up- stroke. On the down-stroke, the working
valve opens and allows the fluid to pass into the tubing. It is then lifted
about 3 ft. by each successive up-stroke until it reaches the surface and
flows from the well through a lead line to a receiving tank (see Fig. 11).

442

INVESTIGATIONS CONCERNING OIL-WATER EMULSION

Bleeder for Sampling

Adjuster
Adjuster Board

Walking Beam

Polish Bod

Li Stuffing-box

Lead Line to Tauk

Lead Lines to Gas or Oil
Big Floor

Tubing

Sucker Bod
Working Barrel

Working Valve
Standing Valve

! :

Perforation
Anchor

FIG. ll. DIAGRAM OF WORKING PARTS OP PRODUCING OIL WELL.

ALEX. W. MCCOY, H. R. SHIDEL AND E. A. TRAGER

443

When a sample is to be taken, the check valve on the tank lead line is
closed so that the fluid coming from the tubing is not affected by the back
pressure from the tank. The valve on the short lead line is opened and
the sample is caught in a bucket (see Fig. 12) and allowed to settle
for about 30 sec. The vertical cylinder is then placed in the guides of the
bucket, separating a representative column measuring about 90 or 100
c.c. of fluid, which is drawn off through the small valve in the bottom of the
bucket. The sample is then centrifuged, the oil, B. S., and water separat-
ing out. By plotting the results of such samples, taken every 10 min.,

FIG. 12. DIAGRAM OF SAMPLE BUCKET.

many irregular conditions have been noted. All producing oil wells do
not perform in the same manner; some of the different conditions are
shown by the accompanying charts.

Fig. 13 shows the graph of a well producing a high percentage of water;
there is no emulsion in the fluid. The oil and water remains in about the
same ratio over a period of 8 hr. The well was pumping about 200 bbl.
per day when this test was made. Fig. 14 also shows a graph of a well
making a large percentage of water; there is, however, a small percentage
of emulsion plotted through the entire time of the test. Fig. 15 represents
a well producing a large percentage of water and a comparatively large
percentage of B. S.

Fig. 16 shows the graph of a well producing a low percentage of water,
a high percentage of oil, and a comparatively high percentage of emulsion.

444

INVESTIGATIONS CONCERNING OIL-WATER EMULSION

Fig. 17 illustrates a well that has just pumped-off a head of water, after
which the percentage of oil suddenly rose and remained about the same for
some time then gradually decreased. At the time of the increase in the

IOC

Sso

/UVA

Oil
B.8.

LEGEND

Water

9:00

5:00

10:00 11:00 12:00 1:00 2:00 3:00 4:00

AJVI. Time PJVf.

FIG. 13. GRAPH OF WELL PRODUCING HIGH PERCENTAGE OP WATER.

6:00

1UU
90
80
70
60
50
40
20
20
10

fiafi

AX\

a^-a

P*A

^0.^,^ 0- J

'N 0^-^

C>-0

a-"

V \

LEGEND
on

B S

\Vutur -

>S _y

_ /s

NrV

\M^^

v^W

r^o^V

O--O-O-0-O-C

^.O-O^-^-O-"

-O.Q-O-O-O-I

-o-o-o-o o-<

--O-O^Q O-O-(

o-o o

8.-00

11:00

4:00

5:00

12:00 1:00 2:00 3:00

AJVI. Time P.M.

FIG. 14. GRAPH OF WELL PRODUCING LARGE PERCENTAGE OF WATER AND SMALL

PERCENTAGE OF EMULSION.

percentage of oil, the percentage of B. S. rose and continued to increase
at about the same rate as the oil dropped later. The fluid came from
the tubing much more slowly as pumping progressed. Fig. 18 shows a

ALEX. W. MCCOY, H. B. SHIDEL AND E. A. TEAGER

445

greater increase in the percentage of B. S. The amount of fluid produced
during the last hour was 25 per cent, of the amount pumped during the
first hour of the test.

100

80
70
60
50

30
20
10

FIG. ]

100
90
80
70

v
U 50

30
20
10

on LEGEND

B 8
Water

J?
/\

, n '

\ / \/

' V N

-\ A

,\ /- A

' ' '-,

' V

v \

' 4 s >

a/ \/ > ~'

^v^\

yv-^

^^v

S^s^

^V^ 1

H^V

^52-

/ \ '*

X\ /I

\ A

I A ;/

," /

' v x\

^ '

i v

"v V/

v x

' W

^'\'

:00 9:00 10:00 11.00 12:00 1:00 2:00 3:00 4:00 5:0
A.M. Time P.M.

15. GRAPH OP WELL PRODUCING LARGE PERCENTAGE OP WATER AND COMPARE
TIVELY LARGE PERCENTAGE OP B. S.

sAA<

&.,.,

^-^oV^

V-o^ />-(

A^/^

-^>^o-.

sA-A

JHV^,

LEGEND
Oil

A/V

r ^^v

NS>^

A/V

k p-'* x '0

V-"0-o-.,

_.o-.o--o~c-o~i

^o-o-o-o-- -'

^-O-O-.o-o.o..,

r o-o~a. (r O' t

*i4^

"o-o-o-o-'O-'

h-cx o-o-o

30 9:30 10:30 11:30 12:00 1:30 2:30 3:30 4:30 5:3
AM. Time P.M.

FIG. 16. GRAPH OP WELL PRODUCING LOW PERCENTAGE OP WATER, HIGH PERCENTAGE
OP OIL, AND COMPARATIVELY HIGH PERCENTAGE OP EMULSION.

Fig. 19 represents the behavior of a well pumping all water for several
hours; after this was exhausted the percentage of oil increased rapidly.
The water pumped during the early hours of the test was the water that

446

INVESTIGATIONS CONCERNING OIL-WATER EMULSION

separated out of the fluid behind the tubing. As the head of fluid was
reduced, the oil finally came into the tubing. The percentage of B. S.
was practically nil.

10U
90
80
70
60

50
*Ji

20
10
'

s
F

100

90
80
70
60
<J 50
* 46
30
26

(

LEGEND

Water

^^^

Sx N^

Wv,

-v,,

\
\

^^^

/>o^>-o-^

sf^ P-*

=v^

X ^

....

-0-O--O--O-O--

:00 9:00 10:00 11:00 12:00 1:00 2:00 8:00 4:00 5:0
AM. Time PM.

IG. 17. GRAPH OF WELL THAT HAS JUST PUMPED OFF HEAD OF WATER.

,A,

01, LEGEND I

^^\

~^v

Water-- - j

ro ^-o^

^v.

V -fc_

^-0

s ^^

s^-

Yu S

-v^.

j^o-o-^-o-o--

f "0--0"0"0-

^^o-svx,' -

:00 :00 10:00 11:00 12:00 1:00 2:00 3:00 4:00 5:0

AJV1. Time P.M.

FIG. 18. SIMILAR TO FIG. 17 BUT SHOWING GREATER INCREASE IN PERCENTAGE OF B. s.

Fig. 20 is the graph of a well that pumped only 6 hr. during the day.
The fluid in the tubing was composed entirely of oil and B. S., which did
not separate out. The high percentage of water following was probably

ALEX. W. MCCOY, H. R. SHIDEL AND E. A. TRAGER

447

the accumulation of water behind the tubing, which passed into the hole
during the shutdown. When the water was about exhausted, the per-
centages of oil and B. S. were about the same as when the well was started.

100
00

40
30
20

i
., i

oil LEGEND

" B.8.
Water

' W *

GTE

1 t\h

i pa

/ ,

in 2

^
o-o-o-o-<

:00 9:00 10:00 11:00 12:00 1:00 2:00 3:00 4:00 5:0
AJVI. Time PJVI.

FIG. 19. BEHAVIOR OP WELL PUMPING ALL WATER FOR SEVERAL HOURS.

aft

Oil

LEGEND

B.8.

Water

80
70

O-CK,

) O

' 60

0) Kf)

o-o-<

f "^^^

jri

,c~^

r-o-o-q,

i L

/ %tr/

WoZ

"OT-O-O--O

00 9:

00 10

00 11:

.00 1:

90 2:(

) 3:

)0 4:

00 5.-OC

AJVI. Time PJVI.

FIG. 20. GRAPH OP WELL PUMPED 6 HR. A DAY.

A well of this order, when pumping continually, would not show such an
erratic condition, as there would be no chance for a large head of water to
collect in the hole.

448

INVESTIGATIONS CONCERNING OIL-WATER EMULSION

Fig. 21 shows the action of a well producing an extremely high per-
centage of B. S. with small percentages of oil and water. The well was
shut down for 3% hr. When pumping was started again, it first pro-

100

j|L4

I
\

f^<J 1

^'\

Shut

down

1 j

60 /

g '

r i Ptfl

O 50

rv.

30
a

20 ri
10

FIG. \

100
90
80
70

30
20
10

o r

on LEGEND

B.S.
"Water

1 1

/V^

,-\\

r-/'

^ *s

/ "^

:30 10:30 11:30 12:30 1:30 2:30 S:30 4:30 5:30 6:30
AM. Time P.M.

51. GRAPH OP WELL PRODUCING EXTREMELY HIGH PERCENTAGE OP B. s. AND

SMALL PERCENTAGES OP OIL AND WATER.

LEGEND

***A

^V<v .

Water -

/\ Not

-Well shi
6 A.M.

t down frot
>f Night Pre

9 P.M. to
ceding

tyZZl

*-\j^

/A/

vy\

^A^

i ?

\ (\ s

^ A v-^^

l \K

^ & '1 A

a .~\ r

SF f>

0-^.^.0-0-*

o-o-^-o-*

X *

:00 8:00 9:00 10:00 11:00 12:00 1:00 2:00 3:00 4:00

A.M. Time P.M.

FIG. 22. GRAPH OP WELL PUMPING LARGE AMOUNT OP FLUID AT START.

duced the same percentage of B. S. as before. Within 40 min., though,
the high percentage of B. S. dropped to nothing with a great increase of
water. At this time, the percentage of oil increased some. In 2 hr.

ALEX. W. MCCOY, H. R. SHIDEL AND E. A. TRACER

449

the water was exhausted and the well started to operate with a more regu-
lar flow. The influx of water was due to the accumulation of water
behind the tubing, during the shutdown.

**'

UMOQ inqg H

a.S'S

i?*J

^S>2
I I I
5 *

i.f

sill

5 a>OHO.

"--Q.- .

anijdmnj

Fig. 22 shows a well that was pumping a large amount of fluid at the
start, the greater percentage of which was oil. As pumping continued,
the percentage of oil decreased and that of the B. S. increased. There was
a perceptible rise in the percentage of water too. At the end of the test,

29,

450 INVESTIGATIONS CONCERNING OIL-WATER EMULSION

the well was producing about one-third the amount of fluid that it did at
first.

Fig. 23 illustrates the performance of a well from the time the pump
was started until it was stopped. At first, the well produced a good per-
centage of oil, which rapidly decreased to nothing. This percentage
represents the oil that had settled in the tubing during the 12-hr, shut-
down previous to starting. After this was pumped out, the well produced
nothing but water for several hours; oil was then noted. By this time,
the water in the tubing, behind the tubing, and some that had probably
been backed up in the oil sand had been pumped off. The oil that had
separated out to the top of the water outside of the tubing was being
pumped. Less fluid was pumped at this time than when only water was
being produced. During the next 2 hr., the well was producing at about
the same rate. Undoubtedly, some of this fluid was partly accumulated
during the shutdown and partly coming into the well during the pumping.
After this, a decided drop in the amount of production was noted, with a
decrease in percentage of water and an increase in the percentage of oil.
The fluid from this time on was probably coming direct from the sand.

Fig. 24 shows the performance of an oil well over a period of 33 hr.
During that time several experiments were tried and the results noted.
At 9:30 A.M., the pump was started, showing a high percentage of oil,
which dropped materially within 10 min.; this was the oil that had settled
out during the shutdown. The well produced a large percentage of B. S.
for 1J^ hr. From 11:10 A.M. to 11:30 A.M., there was a large increase
in the percentage of oil followed by a sudden and greater drop than before.
This was the oil that had risen to the top of the fluid around the tubing
during the period of shutdown. From 12 : 20 P.M. until 6 : 20 P.M., the well
was pumping about as fast as oil and water were coming from sand; gradu-
ally a big increase of B. S. was noted. From 8 : 30 P.M. until 11 : 30 P.M., the
well was shut down . When it started to pump agai, the first test reported
a high percentage of oil, which immediately dropped and the well produced
fluid in about the same percentages as that before the shutdown until
1 : 50 A.M. At this time an increase in the percentage of oil was noted,
followed immediately by the correspondingly large increase of water.

The fluctuations following are the results of quantities of oil and water
getting into the working barrel in separate bodies. From 4 until 8
o'clock, the well was operating with about an average percentage of oil,
B. S. and water. The well was shut down from 8:40 A.M. until 9:20
A.M. and from then until 11 :20 A.M., it operated about the same as it did
from 4 A.M. until 8 A.M. At this time there was a noted increase of water.
The fluctuation of oil and water was due to the separation around the
tubing during the shutdown. From 12:10 until 5:30, the well operated
with a regular, or normal, flow.

ALEX. W. MCCOY, H. R. SHIDEL AND E. A. TRAGER

451

8 g

8 8 s

00^,

452 INVESTIGATIONS CONCERNING OIL-WATER EMULSION

An interesting feature of the curve is the fact that after the well had
been standing idle for a while it produced with a regular and then an
irregular flow. The average production of the well was about 40 per
cent, oil, 50 per cent. B. S., and 10 per cent, water. This mixture in the
tubing did not settle out readily during the shutdown so that when the
well started producing again it pumped approximately this ratio of fluid
for the first 2 hr., clearing the tubing of the fluid left there during the idle
period. While the well was not operating, oil and water filled up behind
the tubing from the sand, which was pumped largely as clear oil and water
with comparatively little B. S. after the fluid in the tubing was exhausted.
When the accumulated head behind the tubing was reduced, the normal
production returned. This series of conditions followed each shutdown.
The B. S. content is only important when there is no large head of fluid
behind the tubing. As shown by the graph, the B. S. content increased
materially from 6 until 8 P.M., after the normal flow had gone on for 5 hr.
Pumping was no doubt going on at a faster rate than the production
from the sand so that gas, air, or voids in the fluid column were admitted
and the oil emulsified to a greater amount.

Referring again to Fig. 23, the following computation was made to
determine the amount of fluid at different times during the test. During
the first hour (10: 10 to 11 : 10 A.M.) of pumping the average of oil content
was 83 per cent. The beam was making 15 strokes per minute and it
took two strokes to fill a bucket of 7 qt. (6.61.) capacity. Consequently,
this is equal to 786 gal. (2975 1.) per hour or about 18.7 bbl. per hour. If
the oil content is 83 per cent, of this fluid, the amount of oil pumped dur-
ing this period is 15.52 bbl. For the next 6J hr., the well produced prac-
tically no oil.

From 5:20 to 7:20 P.M., the well was producing about 20 per cent. oil.
The b earn wasmaking 15 strokes per minute and it took four strokes to
fill a bucket of 7 qt. capacity. This is equal to 393.6 gal. (1490 1.) or
9.37 bbl. of fluid per hour. If the oil content is 20 per cent, of this fluid,
the amount of oil pumped during this period is 3.75 barrels.

From 7:20 to 10:00 P.M., the well was producing about 25 per cent. oil.
The beam was making 15 strokes per minute and it took six strokes to
fill a bucket of 7 qt. capacity. This amount is equal to 262.2 gal. (992 1.)
or 6.24 bbl. of fluid per hour. If the oil content is 25 per cent, of this
fluid, the amount of oil pumped during this period is 4.16 barrels.

The total amount of oil produced is: 15.52 + 3.75 -f 4.16 = 23.43
bbl. The total amount of B. S. and water produced is: 115.38 + 14.99
+ 12.48 = 146.04 bbl. The total amount of fluid is: 23.43 + 146.04
= 169.47 bbl. During the 12-hr, shutdown, the oil and water were
allowed to accumulate in the well. The tubing remained full of fluid
as it was when pumping was started. The fluid entering the well filled
up behind the tubing.

ALEX. W. MCCOY, H. R. SHIDEL AND E. A. TBAGER 453

The following computation shows the amount of time required for the
raising of the fluid at the bottom of the well to the top: Area of 3-in.
tubing is 7.06 sq. in. Area of %-in. rods is 0.44 sq. in. ; difference, 6.62 sq.
in. The number of cubic inches in 1 ft. of 3-in. (76-mm.) tubing is equal
to 6.62 by 12 in. or 79.44; then 2.91 ft. of 3-in. tubing contains 1 gal. of
fluid. The depth of the well, 2425 ft. (739 m.), divided by 2.91 is equal to
the number of gallons of fluid in the tubing, which is 833.3 gal. or 19.84 bbl.
Pumping at the rate of 18.71 bbl. per hour, the time that it would require

to empty the tubing would be 1 ' 1 which is equal to 1.06 hr. or 1 hr.

lo./ 1

4 min. It will be noted by the graph that the big influx of water came
in 1 hr. 10 min. after the well started to pump.

Referring to Fig. 24, the following computation has been made to show
the amount of time required in this well for the raising of the fluid from
the bottom to the top. The depth of the well (2475 ft.) divided by 2.91
is equal to the number of gallons of fluid in the tubing, which is 850 gal.,
or 20.2 bbl. Pumping at the rate of 8.71 bbl. per hour, the time required

20 2
to empty the tubing would be ^~ which is equal to 2.32 hr. or 2 hr.

O. I 1

19 min. The well was pumped at the above rate beginning at 11 : 30 P.M.
and the time required for the first big fluctuation to occur was 2 hr.

20 min. These figures give an idea of the time required to pump the
fluid from the tubing and the variation of the same in different wells.

The question naturally arises as to whether or not the separation of oil
and water while passing through the tubing is sufficient to cause a dis-
crepancy in the ratios of oil and water in each unit volume as it flows from
the bleeder, and the ratio of the fluids as they enter the perforations. In
other words, after the well has pumped the full column of fluid in and be-
hind the tubing, are the proportions of oil and water at the bleeder the
same as they are in entering from the sand? The rate of separation of oil
globules in a water column depends on the difference in the specific
gravity of the two liquids, the temperature of the same, and the size
of the globules. If the full column of fluid is lifted 2500 ft. (762 m.) in 1 or
2 hr., certainly that time is sufficient for considerable separation if the
fluid remains quiet. However, it has been noted by experiment that a
slight stirring will prevent any separation of the fluids, and since the
rods are constantly flapping through the fluid column, it seems that any
tendency to separate while pumping would be greatly if not altogether
reduced. Moreover, if the water from each unit volume should be con-
stantly descending to the next unit volume etc. all the way down the
column, the bleeder would still receive something of the same ratio,
only apparently at later time.

From a number of the curves, it will be noted that after a well has
been pumped for several hours, the ratios of oil, B. S., and water tend to

454 INVESTIGATIONS CONCERNING OIL-WATER EMULSION

remain nearly constant, without large or rapid fluctuations. This may
continue for a long time, only after the fluid head behind the tubing has
been reduced. For that and the above reasons, we have considered the
ratios at the bleeder when the fluid head is once reduced to be the same
as the ratios of water and oil entering from the sand and have called this
the "normal flow."

CONCLUSION

Permanent B. S. is an emulsion of very small water bubbles in oil
having a diameter generally less than 0.5 mm. The oil may be relatively
clean or it may contain variable amounts of suspended matter. There are
generally a few air bubbles present.

The behavior of B. S. on heating may be used as an economically
important basis for division into two groups. In the first group, the
water separates from the oil rapidly with a small amount of heating.
In the second group, the water can be removed only by distillation.

To form B. S., it is necessary to have present, in addition to oil and
water, either air, a gas, or voids in the continuity of the fluid, i.e., a break
in the fluid.

The percentages of oil, B. S., and water vary in the individual wells;
each well is a problem in itself.

A small steady amount of B. S. is probably due to bad valves and cups.
Percentages of B. S. are increased as the column of fluid around the tubing
is exhausted ; such a condition allows air to enter the working barrel or a
break to occur in the column of fluid. This condition is responsible for
large amounts of B. S. The bubbles of the different liquids and gases are
made smaller and consequently more stable by the whipping of the rods.

The maximum efficiency of a pumping well, which is producing both
water and oil, is obtained when the fluid level is kept above the perforated
tubing and below the point where the accumulated head of water would
stop the flow of oil into the hole, and when the fluid is pumped at the same
rate that it comes from the sand. Such conditions can only be deter-
mined by a special test of the individual well.

DISCUSSION

A. W. AMBROSE, Washington, D. C. Did you make any analysis of
the amount of emulsion at the well and after you flowed it through a
lead line to the storage tank?

E. A. TRACER. B. S. can be formed in passing through a lead line by
the friction due to the roughness of the pipe and the irregularities at the
joints.

R. W. MOORE. Did you find the percentage of water to be limited to
the percentage of oil in the emulsion which formed?

DISCUSSION 455

E. A. TRAGER. Yes, the percentage is about 67 per cent, water and 23
per cent. oil.

R. W. MOORE. If you added more water would the emulsion be
permanent?

E. A. TRAGER. Yes, it would be permanent, but the excess water
would separate out.

THE CHAIRMAN (C. W. WASHBURNE, New York, N. Y.). Did you
use hot or cold water in these experiments?

E. A. TRACER. It makes no difference which is used. We tried to
determine whether the composition of B. S. formed in the presence of
excess water would differ from that formed in the presence of excess oil.
The percentage composition in each case appears to be the same.

F. G. COTTRELL, Washington, D. C. In electrical demulsification
experiments in the West a number of years ago, we found no lower limit
to the size of globules in an emulsion that could be dealt with, and I
believe this has been borne out in the operation of the commercial plants
that grew out of this work and are in operation today. I am therefore
surprised at the results that Mr. Trager has secured, and am inclined to
think that he may not have applied the treatment in the same way,
because it was with those very fine emulsions that we were working in our
experiments.

E. A. TRAGER. The chemical laboratory worked on this same sub-
ject and tried using a high voltage current to break down the emulsion,
but the results were not commercially practical for it was found necessary
to treat fine emulsions several times before they were completely broken
down.

F. G. COTTRELL. Do you know the details of the experiments the
voltages and conditions?

CHAIRMAN WASHBURNE. I believe you used high voltages in your
experiments did you not, and alternating current?

F. G. COTTRELL. Yes.

CHAIRMAN WASHBURNE. It seems to me, since there is no doubt that
every globule must have its charge of static electricity, the smaller the
globule, the easier it would be moved by electrical currents and discharges.
The normal static charges will be of like kind and proportional to the
surface area of the globules of oil which will vary with the square of the
radius, while the volume to be moved will be proportional to the cube of
the radius. It is very evident, from the consideration of squares versus

456 INVESTIGATIONS CONCERNING OIL-WATER EMULSION

cubes, that it must be easier to combine large drops than small ones,
because the smaller they are, the easier it is for these little static charges
to keep the globules from quite touching each other. These are all
technical questions and of value in the manipulation of oil emulsions.
In the geological sense, there can be no emulsion. In unlimited time,
the globules must come together and coalesce into larger bodies, thereby
destroying the emulsion.

E. A. TRACER. I had a discussion with Dr. Born (chief chemist)
on the subject of electrical treatment of emulsions and the folio whig are
the conclusions arrived at: The smaller bubbles, as Mr. Washburne
says, move toward the electrode with greater speed, and when two such
bubbles collide or when these small bubbles strike the electrode, the
tendency is rather to break down into even smaller bubbles than to
coalesce. The larger bubbles apparently move more slowly and when
two meet they coalesce quite readily.

F. G. COTTRELL. There are two entirely distinct technical processes
which are often confused with one another. One is the electrical pre-
cipitation of suspended particles out of a gas with a direct or at least
unidirectional current, and the other is the demulsification of liquid
mixtures using an alternating current. The fundamental phenomena on
which these are based are quite different as they are actually carried out.

In the first case, the suspended particle takes a charge by convection
from one electrode, and then is driven over and deposited on the other
electrode. In the case of the demulsification of the oil and water mix-
tures with the alternating current, however, there is no steady migration
toward either electrode. The field is continually reversing so the only
tendency is for the irregularly distributed globules of water to arrange
themselves along the shortest lines between the electrodes. With a very
fine emulsion, you may easily observe this through a microscope, the
globules forming chains and gradually coalescing along these chains. In
all probability, the apparent contact is not directly between the actual
oil in the globules but is a contact of a film of impurities projected to the
surface of the globules. With perfectly pure paraffin-oil and water, it is
very difficult, if not impossible, to make a reasonably permanent emulsion,
but by adding a trace of some resin or similar substance to the oil, the
emulsion becomes stable at once. In crude oils there are varying
amounts of such material. Large drops tend to flow together and break
through that film by the force of gravity. As the size of the globules
decreases, a limit is reached where that force is no longer sufficient to
press the globules together sufficiently to break through these films, but
if the globules are polarized by being brought between the electrodes,
it may be possible to puncture that film enough to make them coalesce.
That is the picture of the process I have formed from watching it under

DISCUSSION 457

the microscope and from the general action I have seen in the electric
treaters. In the case of the demulsifying process, it is not a matter of
electricity being actually discharged from one electrode to the globule,
but of the water being a better conductor, and of the consequent tendency
for water bubbles to arrange themselves in the oil along the shortest lines
between the electrodes. This finally brings the globules into contact and
causes their coalescence.

R. W. MOORE. Did you use distilled water, and what type of oil?

E. A. TRAGEB. In these experiments we used ordinary city water
which comes from the river and contains considerable inorganic matter.
The oil was Augusta crude.

R. W. MOORE. Were any chemical means taken to bring down the
emulsion, such as treating the emulsion with salts?

E. A. TRAGER. We found nothing that would treat all types of
emulsion and do it economically.

CHAIRMAN WASHBURNE. Were any of these experiments repeated
with different oils? Sometimes one emulsified oil will act very differently
from another, although both come from the same field.

E. A. TRACER. We used oil from eight or ten wells, but all the wells
were in Kansas.

CHAIRMAN WASHBURNE. Can you tell us anything about the
chemical means of separating emulsions?

E. A. TRAGER. I believe a process is now being used in Oklahoma
that employs sodium salts and various other compounds (preparations
similar to soft soap), but I do not know whether or not they are com-
mercially successful.

R. W. MOORE. Where the oil is emulsified in the water, heat under
pressure was worked out very nicely in some of the European products,
particularly in lubricating oil. There is a very rapid separation, so, if a
man is treating lubricating oil under a heavy pressure, he can throw that
in his tanks and get a very rapid separation by purely, we may say,
mechanical and not chemical means.

CHAIRMAN WASHBURNE. Is pressure an essential part in that
operation?

R. W. MOORE. I do not know. It is claimed that under ordinary
conditions of heating they got no separation but with the oil and water
emulsion under about 60 Ib. pressure they did.

458 INVESTIGATIONS CONCERNING OIL-WATER EMULSION

R. E. COLLOM,* Washington, D. C. (written discussion). The writer
disagrees with the definition and use of certain terms in the paper. The
second paragraph says: " Laboratory investigations were conducted in
an attempt to learn the composition and some of the properties of emulsi-
fied oil, or B. S., as it is more commonly called. ... In this discussion
we will limit the term B. S. to that heavy, dark-brown emulsion com-
posed of a physical mixture of water, oil, and air with some included inert
matter, either organic or inorganic."

The abbreviation B. S., in oil-field practice, is never properly applied
to an emulsion. B. S. may contain some emulsion in the form of sludge,
which is a mixture of mud derived from clay or shale and emulsified
fluid. But B. S. means "bottom sediments" or " bottom settlings" and
such sediments are entirely different and distinct from oil-water emulsions.
Bottom sediments contain certain definite ingredients of oil-well produc-
tion that have no commercial value. They include sand, mud, sludge,
and other semisolid material. Oil-well emulsions, when properly treated
by electric dehydrators or other means, give up certain quantities of
valuable oil. The term B. S. certainly excludes the greater bulk of emul-
sions, which are nothing more or less than mechanical mixtures of oil and
water. The writer prefers the use of the word "sludge, " rather than the
abbreviation B. S., for the particular physical mixture in bottom sedi-
ments containing emulsion.

Emulsified fluids vary in their combined proportions of oil and water.
The gravities of the oil undoubtedly control the proportion of oil and
water in emulsified mixtures. Light oil will carry less free water in sus-
pension than heavy oil but an emulsion of light oil and water will show a
higher water content than one of heavy oil and water. If the Baume"
gravity of the pure oil in emulsion is known, a fairly close figure for the
percentage of water in the emulsion may be determined in the following
manner. Baume* gravities are proportional to volumes. The Baume*
gravity of water is 10. The Baume" gravity of each fluid, multiplied by
the respective percentage of volume of each fluid and divided by the sum
of percentages of volume, or 1, equals the Baume" gravity of the emulsion.
That is, where

p = gravity of pure oil;

w = gravity of water;

e = gravity of emulsion;

x = per cent volume of pure oil ;

y = per cent volume of water;

-. x + y = 1.0 x-l-y

P py + wy = e p y (p w) = e

6, p, and w are known, solve for y.

Petroleum Technologist, U. S. Bureau of Mines.

DRILLING AND PRODUCTION TECHNIQUE IN THE BAKU OIL FIELDS 459

Drilling and Production Technique in the Baku Oil Fields

BY ARTHUR KNAPP, M. E., SHREVEPORT, LA.

(New York Meeting, February, 1920)

No OIL territory in the world has been so rich in large producing wells,
in a comparatively small area, as the Baku field. Particularly is this
true of the Bibi Eibat field, which formerly produced millions of " poods "
of " gusher," or as it is called in Russia, " fountain " oil. The Bibi Eibat
and Balachany fields have been exhausted of gas and ruined by water, but
the Surachany and Benegadi fields are still fountain territories and many
outlying districts that have only been prospected produce rich fountains.

The method of controlling fountains, or gushers, is the result of growth,
along with the Russian system of drilling, where large diameters and
riveted casing have been in vogue. The screw casing is seldom used
except to exclude water. Formerly the method of finishing wells and
the condition of the casing at the top of the well would not permit
the use of gates, manifolds, and connections as is standard elsewhere.

The life of the flowing wells is very short, particularly those 10 in.
(25 cm.) or more in diameter, which produce large quantities of sand and
often flow for but a few days and are then a complete loss. More than
1,000,000 poods in 24 hr. have been claimed in several instances, but in
no case was the flow for more than a few days.

The oil sands of this district are free uncemented sands and vary
in thickness from paper thin to a maximum of 10 ft. (3 m.). The sands
are interlaid with strata of soft clay. In spite of this, the practice has
been to drill into such sands and produce from the open hole without
screen or liners. Sometimes the casing is set below the oil sand but in
this case holes from 2J^ to 3 in. in diameter are drilled opposite the oil
sand, which would not have the effect of a screen.

Fig. 1 is an outline of the fountain shield ready for the control of a
fountain. It is composed of an inner and an outer covering made from
rough boards. The framework is made of rough round poles. When
a light flow is expected, only the inner lining is built; and when the
fountain comes in unexpectedly, it is often possible to build only the
outer cover. The bridge is for the purpose of renewing the blocks as
they become worn by the flow. The lower block, as here shown, is
made of hardwood and is bolted to the crossbeams with brass bolts.
The grain end is toward the flow. The upper block, as shown here,
is made of cast steel and is also bolted to the crossbeam with brass bolts.

460 DRILLING AND PRODUCTION TECHNIQUE IN THE BAKU OIL FIELDS

Sand Sheave
Crown Block

Feet 3C 32 24 18128 3630242216108 2C"22l8''l2" 34 ' 22" H" 42 3l"26 20 lo" 42 34 28221412

100 I'

| .

;

200

300

400

500

i
i

6 11

f *&

l*El

;

" i

n
i

1000 ' ^j

IK mi

S"p"

S .. '^

8-p-

-*? o

i p

w ^

20H

| $

_,. 1

F rf

1COO

M :

I fl " "

']"

\t\

-p.. ..p

2000

H r * \ y$$ Cement put in through Tubes 'ji

|i (Ml Cement put in under Shoe

it; ij Wft Cement put in through Drilled Boles <f "

!( 1 ooo Drilled Holes

Russian Kivetted Casing

2500

U ij { Screwed Casing

! j' p " u-vV-.Clay Filling

"P" Production

Fio 2.

ARTHUE KNAPP

461

Both blocks may be wood or steel, depending on the fancy of the engi-
neer in charge.

Valves, tees, and lead lines are sometimes put on the well to prevent
its flowing before the shield is complete and to control the well in case
of fire. No attempt is made to control the production or to direct the
flow when the well is put to producing; the well is always allowed to
flow to capacity against the blocks. Usually the valves are cut out

FIG. 3. INTERIOR OF DERRICK SHOWING END OF WALKING BEAM AND TEMPER-SCREW

and rendered useless soon after the flow commences. The wear of the
blocks depends on the flow; sometimes they must be renewed daily.
This arrangement of fountain control is not always effective. The top
of the derrick, blocks and all, is sometimes lifted entirely off and the well
flows wild until it sands up or the flow has weakened sufficiently to allow
the blocks to be replaced. The derricks are usually set on embank-
ments from 6 to 10 ft. high, these embankments being reinforced with
pilings lined with planks. This bank is necessary to allow the oil to flow

462 DRILLING AND PRODUCTION TECHNIQUE IN THE BAKU OIL FIELDS

away from the well and to give space for the handling of the large
amount of sand that some of the wells produce.

Fig. 2 is an exact copy of the record of six wells in the Balachany field.
It shows the average condition of producing wells drilled by the Russian
method. In general, the formation to 1100 ft. (335 m.) is clay, shale, and
sandy shale. Below 1100 ft., there is also soft limestone, soft sandstone,
and hard shale. There are no thick layers of hard rock. Sand, entirely
uncemented, is seldom found except in thin layers between layers of
shale.

FIG 4. WELL BLOWING OUT THROUGH 26-iN. CASING. MAKING GAS,

WATER AND LARGE QUANTITIES OF SAND.

The Russian riveted casing is far from water-tight, which accounts
for the large amount of cement put in around the casing. Sometimes it is
necessary to fill the casing with clay before the liquid cement will remain
behind the casing long enough to set. The cement is put in with pumps,
1 or IJ^-in. (2.5 or 3.8-cm.) pipes being inserted between the casings to
convey it to its place.

The Russian method of drilling makes use of steel poles to actuate
the tools but differs from the Canadian system, which also uses poles of
wood or iron, in that a "free-fall" is used above the tools instead of the

ARTHUR KNAPP 463

tools dropping with the rods. This free-fall picks up the tools at the
bottom of the stroke and releases them at the top of the stroke, allowing
them to fall free to the bottom of the hole. Thus the fall is limited to
the length of the stroke of the walking beam and differs from the American
cable tool system where the fall, due to the elasticity of the drilling cable,
may be several times the stroke of the beam.

The Russian drilling machine is a slow ponderous machine, very
heavy and very hard to handle, transport, and install. It cannot be
said in reality that this machine drills; it manages to worry a hole in the
ground. The results, as shown in the tables, prove this. The large
starting diameters are necessary because of the large number of strings

FIG. 5. TYPICAL VIEW IN BALACHANY.

of casing used and the large oil string necessary for producing by bailing.
Also, there are several producing horizons, and wells are drilled large
into the first horizon so that later they may be deepened. Casing,
both Russian riveted and screwed, is lowered by means of clamps some-
what on the style of the American casing clamp. The Russians have
never developed nor learned to use elevators, spiders and slips, casing
tongs, or other modern oil-well tools, except when these tools have been
brought in with American machinery and used by the American drillers.
The casing is always carried with the tools in the Russian system.
The bit is seldom advanced more than 20 ft. (6 m.) beyond the shoe.
Under-reaming is practised to a large extent.

Tables 1 and 2 are chronological records of two wells shown in Fig. 2.
They give, in detail, the time required for various operations under
ordinary circumstances. When one string of casing has been carried

464 DRILLING AND PRODUCTION TECHNIQUE IN THE BAKU OIL FIELDS

TABLE 1. Casing Record Shown in Well 5, Fig. 2

Days

Depth,
Feei

Advance,
Feet

Average
pei Day,
Feet

Diameter
of Casing,
Inches

Operation

133

Drilling.

Lowering 36-in. casing, 64 ft. per day.

230

Drilling.

Shut down, no boiler water.

260

Drilling.

Shut down, no boiler water.

370

110

Drilling,

Shut down, no boiler water.

585

215

Drilling.

Shut down, no boiler water.

714

129

Drilling.

Lowering 34-in. casing, 90 ft. per day.

1000

286

Drilling.

Lowering 32-in. casing, 90 ft. per day.

1250

250

Drilling.

Working casing.

Lowering 26-in. casing, 210ft. per day

Cementing.

Lowering 20-in. casing, 135 ft. per

day.

1315

Drilling.

Taking out 20-in. riveted casing, 220

ft. per day.

Lowering 20 in. screwed pipe, 100 ft.

per day

143

Cementing.

Lowering 18-in. casing, 120 ft. per

day.

1336

Drilling.

Shut down for repairs.

1449

113

Drilling.

Testing casing.

Cutting off 18-in., lowering 16-in.,

and cementing.

1687

238

Drilling.

165

Lowering 10-in. casing and cement-

ing.

Waiting for cement to set.

Bringing well in.

Days of work, 730; days drilling, 128 or 18.2 per cent.; days lowering casing, 98 or
14.0 per cent. ; days idle, 28 or 0.4 per cent. Average advance per day of actual drilling
13.2 ft. Days of work do not include the last 60 days testing for oil and bringing the
well in.

ABTHUB KNAPP

465

TABLE 2. Casing Record Shown in Well 6, Fig. 2

Days

Depth,
Feet

Advance,
Feet

Average
per Day
Feet

Diameter
of Casing
Inches

Operation

136

Drilling

Lowering 36-in. casing, 34 ft. per day.

150

Drilling.

Testing well for plumbness.

246

Drilling.

Machinery repairs.

373

127

Drilling.

Machinery repairs.

735

362

Drilling.

Lowering 34-in. casing, 29 ft. per day.

987

252

Drilling.

Waiting for material.

Lowering 28-in. casing, 102 ft. per day.

1166

179

Drilling.

Cementing.

Lowering 26-in. casing, 116 ft. per day.

1340

134

Drilling.

Working casing.

Lowering 24-in. casing, 166 ft. per day.

No steam.

1393

Drilling.

Working casing, etc.

Lowering 22-in. casing, 154 ft. per day.

1414

Drilling.

Working casing, etc.

Lowering 20-in. casing, 154 ft. per day.

1484

Drilling, also working casing.

1575

Drilling.

Working casing, etc.

Lowering 18-in. casing, 146 ft. per day.

1676

101

Drilling.

Freeing and repairing casing.

1701

Drilling.

Freeing and repairing casing.

Lowering 16-in. screwed casing, wait-

ing orders.

1911

210

Drilling.

Working casing.

Lowering 14-in. screwed casing, 71 ft.

per day.

General repairs.

1946

Drilling.

Shut down, labor troubles.

2044

Drilling.

8 months waiting result of an offset well

Lowering 12-in. screwed casing, 130

ft. per day.

Repairs.

2184

140

Drilling.

Days of work, 737; days drilling, 268 or 36.3 per cent.; days lowering casing, 130
or 17.5 per cent.; days idle, 29 or 0.4 per cent. Average advance per day of actual
drilling 8.15 ft. Average amount of casing lowered per day, 140 ft.
VOL. LXV, 30.

466 DRILLING AND PRODUCTION TECHNIQUE IN THE BAKU OIL FIELDS

as far as possible, a smaller string must be lowered before drilling can
be continued. The time required for this is a large item and appears in
detail in the column marked Operations. The general character of the
Russian method accounts for most of the slow progress, together with
poor tools, material, and labor. Wells are usually drilled by contractors
who are paid per linear foot on a sliding scale, depending on the depth.
They are paid a fixed sum per day while fishing and are not liable for
casing lost.

Days of work does not include the 8 months waiting on the result
of another well. Working casing includes cementing, testing for water,
raising and lowering casing to free it, cutting off, etc. Days drilling
includes time of raising and lowering tools and the lowering of casing
as the drilling proceeds.

DISCUSSION

I. N. KNAPP, Philadelphia, Pa. (written discussion). I had con-
siderable correspondence with the author of this paper during the two
years he was engaged at Baku, from July, 1914, to August, 1916, and
since his return I have had many interesting talks with him on his Rus-
sian experience. I think, therefore, that instead of making a strictly
technical discussion of the paper, it will be more interesting to include
some personal details.

The author was employed to advise on American methods of drilling
and operating and particularly to introduce American methods of pump-
ing oil from wells. Fully one-third of the oil then being produced around
Baku was used as fuel for bailing the production.

On arriving at his destination he was not allowed by the local Russian
management to go upon the properties of the company that had em-
ployed him. This gave him an opportunity to study the Russian lan-
guage under competent teachers; in 6 mo. he was able to do business
over the telephone in that language. In talking of this I said "It was
extremely fortunate that you were able to learn Russian in such a way
that you did not have to differentiate the common ' cuss words ' of the oil
fields from polite language." To this he replied that Russian is not
commonly spoken by the workmen of the Baku oil fields. The principal
language used is Tartaric with a mixture of Persian, Armenian, and some
Georgian.

After several months of idleness, he was given a practically abandoned
well to put to pumping. The Russian manager seemed to expect him
to tear down the Russian rig and build one in American fashion, which
could easily be made to take a year's time. He chose rather to repair and
line up the old Russian rig and machine already at the well and on running
the tools found a couple of bailers stuck in the hole. The workmen
were surprised to see an American engineer who was not afraid to repair

DISCUSSION 467

one of their machines and operate it. The author soon found that some
of the workmen were good oil men in their way, so after he had run an
impression block, had some fishing tools shaped up, and had cleared the
junk out of the hole, they became willing and helpful workers. He found
blacksmiths and machinists in the field that could do surprisingly good
work, considering the facilities they had. The workmen had never used
American elevators, modern pipe tongs, monkey or Stillson wrenches, so
it was necessary to show them how to use such tools efficiently. The
several large properties of his company had no tools of this kind until
the shipment of American goods arrived.

The first well was soon got on the beam and put to pumping. The
author assures me that there is no more difficulty in pumping a properly
screened well from the Baku sands than from the Midway, Calif., sands
where he has had experience in both drilling for and pumping oil. Also,
he says that many places in Louisiana and in Trinidad present greatei
difficulties in drilling and pumping than Baku.

A second practically abandoned well was turned over to him to be put
to pumping but instead of the good American tubing got for the purpose
a lot of junk tubing that would drop apart before 1000 ft. was run in
the hole was substituted. Each break made a fishing job that would last
some time. After awhile the Russian management forgot about trying
to pump wells.

The author was given an opportunity to become familiar with the
Russian free-fall system of drilling and, for a time, had charge of the
operation of a Holland rig, or European water-flush system, and an
American rotary. He understood that it was compulsory for each oil
property to be managed by a qualified engineer with Russian diplomas
and such managers commonly opposed any innovations on general
principles.

In some of the Government-owned pools, operations are restricted to
hand-dug wells not to exceed a maximum depth of 420 ft. The well
diggers employed are skilled in their trade, which has been carried on in
that region since time immemorial. They are very loyal to their mates.
Men, when digging, are frequently overcome with gas and the workmen
are adepts at resuscitation in such cases. The laws of the country have
been made extremely drastic on deaths caused by asphyxiation. When
the workers conclude that a man is really dead from this cause, they
pound him on the head with a rock or kick in his ribs so as to claim that
he died from an accident and, of course, the authorities decide in such
cases that nobody is to blame.

He further said that the rules laid down for operations in the Baku
field were perhaps made in good faith but many lacked practicability.
For instance, there was a rule that only 60 Ib. of steam was to be allowed
ordinarily on any boiler in the field. American rotary rigs are designed

468 DRILLING AND PRODUCTION TECHNIQUE IN THE BAKU OIL FIELDS

for at least 100 Ib. steam pressure and were hard to operate at the low
pressure on account of the small steam cylinders. Some boilers sent
with such rigs were built under the Burmah specification and really had a
fair factor of safety at 200 Ib. steam pressure. But notwithstanding
all this every boiler in the field must have two safety valves, one of which
is set at 60 Ib. pressure and sealed by a Government engineer. Admit-
tedly the water used is bad but not the slightest regard is paid to the
thickness of the sheets or the workmanship of the boiler. Gradually
the author was permitted to examine all the geological and drilling
records of his company from which the data given in the paper were taken.

There were a few native Russians in the Baku district who had studied
in American and English colleges and occasionally one was employed
in the oil fields. Partly through the influence of these men and partly
because of his ability to speak Russian fluently and to make sketches of
American methods of drilling and operating he was invited, during the
last few months of his stay at Baku, to attend and take part in the pro-
ceedings of the weekly meetings held by the Government engineers in
general charge of the Baku oil fields. He says that it is generally recog-
nized that the days of the rich shallow gushers, or fountains, at Baku
have passed and less expensive methods of drilling and operating must
be adopted, such as is offered by the American method of rotary drilling,
cementing in the casing, screening off the sand, and pumping the wells.

So far as I can see, the first great step toward progress would be to do
away with the former misdirected Governmental interference of all
kinds. Let the investigations be directed by men skilled in the oil
business, and not by the impractical scientist whose findings only serve
to entrench the administrative and bureaucratic machines in the strangle
hold that smothers initiative, progress, and real conservation.

DETERMINATION OF PORE SPACE 469

Determination of Pore Space of Oil and Gas Sands*

BY A. F. MELCHER,! M. S., WASHINGTON, D. C.

(Lake Superior Meeting, August, 1920)

THE present paper is a progress report on an investigation of the
physical factors of oil and gas and especially of their sands, 1 such as pore
space, size of pores or permeability, retentivity, viscosity of the oil,
temperature, pressure, thickness and area of the pay sand, water rela-
tions, and capillarity. The purpose is to determine as many of these
physical factors as possible, and to ascertain the relations existing, directly
or indirectly, between these physical factors and the production of oil
and gas. As yet only pore space 2 and size of grains of pay sands have
been investigated, although an apparatus has been designed to determine
the permeability of a sand to oil, water, or gas under definite drops of
pressure between the entrance face and exit face of the sample.

Messrs. E. W. Shaw, R. Van A. Mills, D. Dale Condit, G. B. Richard-
son, G. C. Matson, and C. H. Wegemann collected the samples upon
which the physical determinations were made. Acknowledgment is
made to my colleagues of the United States Geological Survey for many
suggestions and criticisms; to Mr. Mills for the production data given
of the oil wells from which some of the samples were collected; to Mr.
A. W. McCoy of the Empire Gas and Fuel Co., Bartlesville, Okla., for
many ideas.

DETERMINING PORE SPACE OF OIL AND GAS SANDS

In selecting a method for the determination of pore space, two objects
were kept in mind: First, the method must not only be sufficiently

* Published by permission of the Director, U. S. Geological Survey.
t Associate Physical Geologist, U. S. Geological Survey.

1 Sand is used in this paper with the meaning of oil and gas pay sands as they
exist in nature, either coherent or incoherent. The sand samples tested in this paper
were coherent.

2 The pore space of a rock can be divided into two kinds, the total pore space and
the effective pore space. The total pore space is the total interstitial space and
includes not only the communicating pores, but any isolated pores that may exist.
The effective pore space, on the other hand, is relative, depending on such factors as
the constitution of the liquid, the size of the pores, the material of the rock, tem-
perature, pressure, and other conditions. It is apparent that the total pore space
is a maximum limit for the effective pore space. The method described in this paper
determines the total pore space.

470 DETERMINATION OF PORE SPACE

accurate to be of a truly scientific nature but must also be rapid enough
to justify its commercial use. Second, the method, to have as large a
range as possible, must permit the determination of pore space of many
types of samples of different composition and structure, with great
range of size. The method selected is based on the principle that the
volume of the fragment of the sand minus the volume of its individual
grains equals the volume of the pore space. The volume of the pore
space divided by the volume of the fragment gives the per cent, pore
space by volume. The volume of a fragment of sand is chosen because
it is a constant factor. Density and weight of a fragment of sand are
not constant unless all substances are removed from its pore space, but
will vary with the quantity and kind of material in the pores of the stone.
To determine the pore space of an oil or gas sand, it is quite necessary
to have unbroken fragments or parts of the pay sand as it existed in
nature free from cracks or cleavage planes and its surface free from
foreign material. Disintegrated sand is not so valuable in the determina-
tion of pore space, as it would be impossible to place the separate grains
in their original positions in order that their true interstitial space
might be found. It is better to have several samples from each well,
beginning at the top of the pay sand, or even at the top of the cap-rock
and extending to the bottom of the pay sand, as often the productive
sand is within another sand. The core-drill method of obtaining samples
is the best. Samples are obtained when the well is shot and from drill
cuttings. Sometimes they come up with the bailer and with oil and gas
when oil and gas come out of the well under considerable pressure. Sam-
ples are often obtained from outcrops and, in some cases, where mine
shafts penetrate the pay sand. The fragments are sometimes irregular
and quite small, weighing less than 1 gram.

DIPPING SAMPLES IN PARAFFIN

Sometimes the texture of the samples is so loose that it is difficult to
keep the grains of sand from rubbing off while handling them; other frag-
ments are firmer and more compact. It was because of this looseness
of texture and the small size of some of the samples that the method of
dipping in paraffin 3 was adopted. After the surface of a sample was

Julius Hirschwald ("Die Priifung der Natiirlichen Bausteine auf ihre Wetter-
bestandigkeit." Berlin, 1908. W. Ernst und Sohn) describes a method of dipping
the specimens in paraffin, which he used to determine the specific gravity of building
stones. The volumenometer was employed instead of weighing the sample in water
to find the specific gravity. He determined the absolute pore space from a compari-
son of the specific gravity of the powdered stone with that of a greater fragment
of the stone. By the method of finding the pore space by a comparison of specific
gravities, Hirschwald eliminates the difficulties of saturating the sample with water,
but in choosing the specific gravity instead of volume he retains the difficulties of
removing foreign material from the pores of his fragment specimen.

A. F. MELCHEK 471

thoroughly cleaned of foreign material with an assay brush and loose
particles brushed off, it was broken into two parts; one part was used
for finding the volume of-the fragment and the other was used for finding
the volume of the individual grains making up the fragment.

The pieces that were to be used for finding the volume of the fragment
were weighed and then dipped into parafiiin heated to a temperature a
little above its melting point. The layer of paraffin around the sample
was then examined for air bubbles and pinholes. If any were found,
they were removed by remelting the paraffin at that point with the end
of a hot wire.

* a

FIG. 1. SAMPLES OF OIL- AND GAS-BEABING SANDS DIPPED IN PARAFFIN; THE SCALE

EEADS IN CENTIMETERS.

The fragments are best dipped by holding them with the fingers.
First, the half of the sample opposite the fingers is dipped, then the sample
is turned around and the other half is dipped. The samples should never
remain in the melted paraffin longer than 2 or 3 sec., and very small samples
or very porous ones should be immersed for shorter periods. Bubbles
should not be permitted to come out of the samples as they usually
indicate that the paraffin is beginning to enter the pores. If there is any
doubt about the paraffin entering the pores of the sample, the specimen
may be broken, after it is weighed, in distilled water and examined with

472 DETERMINATION OF PORE SPACE

a hand lens or microscope, depending on the size of the pores. It will
be found that, after a little practice, if the samples are cold, there will
not be much difficulty in dipping them so that the paraffin will not enter
the pores, as the paraffin almost immediately hardens when it comes into
contact with the cold surface of the sand. When the paraffin cools,
the sample with its coating is weighed to determine the weight of the
paraffin.

DETERMINING VOLUME OF FRAGMENT

The sample with the coating of paraffin is suspended in distilled
water by a No. 30 B. & S. gage platinum wire and weighed; a fine wire
is used so that the error due to surface tension will be as small as possible.
The water should have been boiled and its temperature taken to one-
tenth of a degree at the time of the weighing. The sample is then
removed from the water, dried by pressing the surface against bibulous
paper or a smooth towel and weighed in air. This weighing is made to
see whether the sample absorbed any water. If an appreciable quantity
of water is absorbed, a correction can be made to the weight of water
displaced from the difference between the last weighing and the former
weighing of the sample plus the paraffin in air.

From the weight of the water displaced, its temperature, and den-
sity, the volume of the sample plus the volume of the paraffin can be
obtained. The tables by P. Chappuis 4 on the change of density with the
temperature of pure water free from air were used. From a previous
determination of the density of paraffin, which in this case is 0.906, and
the weight of the paraffin covering the sample, its volume can be ob-
tained. Subtracting this volume from the total volume of the sample,
plus the volume of the paraffin, gives the volume of the fragment of stone
used.

DETERMINING VOLUME OF INDIVIDUAL GRAINS

The second part of the sample is weighed and crushed in an agate
crucible into its separate particles; or, in the case of a very fine sand,
until it will pass through a 100-mesh sieve. It is again weighed and
thoroughly dried in an electric oven, or better in the Steiger toluene 5
bath at from 100 to 150 C. for 30 min. to 1 hr.; a lower temperature
is used when there is danger of driving off an appreciable quantity of
combined water. It is then placed in a dessicator to cool. After the
particles have cooled, the sample is weighed and exposed to the air to
take up moisture. After the particles have reached a constant weight,

4 Bureau International des Poids et Mesures, Travaux et Memoirs (1907) 13;
U. S. Bureau of Standards, Circular 19, 5th ed., Table 27.
U. S. Geol. Survey Bull. 422 (1910) 75-76.

A. F. MELCHER

473

or nearly so, they are again weighed to correct for hydroscopic water.
The particles of sand are then transferred to the pycnometer, using
glazed paper. The pycnometer plus the sample are weighed to correct
for the loss in transfer. The pycnometers used are of the type designed
by John Johnston and L. H. Adams, 6 of the Carnegie Institution.

The advantages of this type of pycnometer over others are: (1) There
is no appreciable loss by evaporation of the liquid from the pycnometer,
the pycnometer can, therefore, be allowed to stand in the balance case

FIG. 2. APPARATUS FOB REMOVING THE AIR FROM DISINTEGRATED SAND IN
PYCNOMETER, AND TWO TYPES OF PYCNOMETERS, THE JOHNSTON & ADAMS PLANE-
JOINT PYCNOMETERS, No. 1, AND COMMON PYCNOMETERS, No. 2.

until temperature and moisture equilibrium is attained; (2) there is no
error due to grease, which is necessary in other pycnometers where the
stopper fits into flask; (3) any particle of grit or dirt can be easily wiped
from the joint between the stopper and flask. It is about as easy to
obtain an accuracy in density of 2 in the fourth decimal place by this
pycnometer as it is of 2 in the third decimal place for the ordinary type
of pycnometer, where the stopper fits inside the flask. The device of G.

'Jnl Amer. Chem. Soc. (1912) 34, 566.

474 DETERMINATION OF PORE SPACE

E. Moore, 7 slightly modified by Day and Allen, 8 was used for the evacua-
tion of the air from the ground particles. Fig. 2 shows this apparatus
with pycnometers of two types the Johnston & Adams plane joint
pycnometer and the common pycnometer, in which the stopper fits inside
the neck of the flask.

After the pycnometer is nearly filled with boiled distilled water, the
aspirator is removed and the pycnometer is placed in a constant-tem-
perature thermostat regulated to 0.1 C. The filling of the pycnometer
is completed from distilled water taken from another vessel in the thermo-
stat. The pycnometer is then removed from the thermostat and weighed
after its outside surface has been dried with a towel. From a previous
calibration of the pycnometer, which gives the weight of the water nec-
essary to fill the pycnometer, the weight of water that the crushed
sample displaced is found. The volume of the ground particles in the
pycnometer is found from the weight of water displaced and the table
of densities of water at the temperature of the thermostat.

By proportion, the total volume of grains in the fragment dipped in
paraffin is determined. Then the volume of the fragment dipped in
paraffin minus the volume of its grains is equal to the volume of the pore
space. This volume divided by the volume of the fragment gives the
per cent, pore space by volume.

DETERMINING PORE SPACE OF VERY SMALL SAMPLES

In case the sample is too small to break into two parts, the whole
sample can be dipped into paraffin and the paraffin burned off, if the
grains of the sample are of sufficiently pure quartz not to be appreciably
changed in volume or weight by the burning. In many cases the paraffin
can easily be shaved and brushed off with a knife and assay brush and
a new weighing made to determine the. loss of weight of particles brushed
off. In case there is oil in the fragment that is crushed, the oil is either
burned out by placing the crushed sample in a platinum crucible or it is
dissolved by a solvent, as petroleum ether or carbon tetrachloride.
It was possible to burn out the oil in nearly all cases as most of the samples
consisted of practically pure quartz.

BASIC PRINCIPLE OF METHOD

This method is based upon the principle that the volume of the frag-
ment minus the volume of its grains equals the volume of the pore space.
Let V = volume of fragment;

Vt a = volume of grains of that fragment free from moisture;

V p volume of pore space;

v 9 = v - v to 0)

Am. Jrd. Sci. [3] (1872) 3, 41.

Carnegie Institution of Washington Pub. 31; U. S. Geol. Survey Bull. 422
(1910) 4&-50

A. F. MELCHER 475

The per cent, pore space is

~\T \ ~\T / V /

Now, the problem is to find V and V tg in known quantities, and quan-
tities that can easily be obtained experimentally. In order to do this,
the sample is broken into two parts, one to be dipped in paraffin and the
other to be used for the determination of the volume of the grains.

Let W and W\ = weights, respectively, of the two pieces;

W P = weight of one of fragments dipped in paraffin;
Wp W = weight of paraffin.

The volume of the paraffin is

Vpl = 0*906 '
wherein 0.906 = density of paraffin at 20.4 C.

Let W p i = weight of fragment dipped in paraffin plus wire carrier

in boiled distilled water;

W e = weight of wire carrier immersed an equal distance in
water as when fragment was attached.

The weight of the water displaced by the fragment plus its' coating
of paraffin is W p (W P \ W c ), and the volume of the fragment is

-v*

W P - (W Pl - W e )

where D t = density of water taken from the density tables at the tem-
perature of the water when the weighing was made. Substituting for
V p i its value,

W P - (W P , - W c ) _ Wp-W
D t 0.906

If W g = weight of grains immediately after sample is crushed, Wi
W g = weight lost or gained in breaking up sample into its separate
grains or so that the material will pass through a 100-mesh sieve in case
the sand is very fine. The difference (W\ W g ) is usually quite small.
It can be made a negligible quantity by first using the Ellis crucible 9
for breaking the fragments into coarse particles and then using the agate
crucible for the finer grinding. In real fine material, there is an error due
to the particles taking up moisture, but in this work the error is inap-
preciable or the above quantity can be used as a correction.

9 U. S. Geol. Survey Bull 422, 50-51.

476 DETERMINATION OF PORE SPACE

Let

Wg\ = weight of crushed sample, after drying, at 100 to 150 C.

in an electric oven for about 1 hr. ;
Wk weight of pycnometer;
Wki = weight of water content of pycnometer at standardized

temperature ;

Wk* = weight of pycnometer with crushed sample filled with water;
Da = density of water at temperature t\.
The weight of water displaced by the crushed sample is,

W k > = W k i - [W n - (W k + W,i)]
and the volume of the grains is

._ W ks _ W kl - [W kz - (W k

Then the total volume of the grains V tg in the fragment that was coated
with paraffin is found from the proportion W g : W V a : V t g', or, ex-
pressed in the form of an equation,

W
Substituting for V g its value in equation (4),

-[W k2 - (W k + W,i)]}

W D tl
Substituting in equation (2) for V and V tg their values,

P = 100 [l - D ' W

in which W k , W k \, W c are experimental constants and D t and Da are
constants found from the tables on density of water free from air. These
leave six quantities, W , W g , W k *, W g i, W P) and W P i to be found by weigh-
ing. The density of the grains free from moisture, or specific gravity
of the grains referred to water at 4 C. as unity is,

D- W ' 1

17
For very accurate determination of pore space, it is necessary to add

a correction to some of the weighings for buoyancy of the air. In this
method it is not necessary to dry the fragments. In a number of cases
the percentages of different diameters (of grains) were found by sieving.

ADVANTAGES OF METHODS ADOPTED

The method used will determine the pore space of oil- and gas-bearing
sands in about one-tenth the time it takes by the water absorption
method, and is more accurate. In most cases it would be impossible to
determine the pore space of the samples by water absorption with sufficient

A. F. MELCHER

477

accuracy even for commercial use, on account of the small size and lack
of solidity of most of the available fragments. Pore space determina-
tions can be made of chunk samples that weigh 0.1 oz. with an error of
less than 1 per cent. The pore space of a chunk sample weighing 0.05
oz., the grains of which will pass through a No. 20 mesh sieve (and most
grains of oil and gas sands will pass through a mesh of this size) can be
determined with sufficient accuracy for commercial use.

One of the chief sources of error in determining the pore space of a
small sample by water absorption is that the quantity of water that may
be taken from the pores or left on the surface in drying the sample may be
a large percentage of the total amount of water absorbed. It is also
quite difficult to clean thoroughly oil- and gas-bearing fragments of sands
from their oil, water, and gas, as well as to saturate them with water
after they have been cleaned. Another difficulty met in loosely connected
grains of a sample is that the sample may disintegrate when it is placed
in water. These sources of error and difficulties are eliminated by the
method that has been described.

POROSITY TESTS ON BUILDING STONES

The following are some determinations of pore space by Julius
Hirschwald 10 and show the variations in the value of porosity of different
methods of water absorption on the same sample. These porosity
tests were made on building stones.

Percentage Proportion of Water Absorption to Total Pore Space*

Number of
Sample

By Method of
Quick Immersion

By Method of
Gradual
Immersion

By Method of
Gradual
Immersion
in Vacuum

By Method of
Pressure 50-150
Atmospheres

53.0

61.3

85.5

100.0

45.9

52.2

61.1

100.0

71.3

81.2

81.5

100.0

60.9

63.0

99.4

100.0

72.6

77.2

81.0

100.0

53.3

54.6

99.5

100.0

47.6

49.7

96.1

100.0

* The total pore space in these seven cases is the same as the pore space deter-
mined by the method of applying a pressure of 50-150 atmospheres to the sample
under water immediately after the method of gradual immersion in water under a
vacuum has been completed.

10 Julius Hirschwald: Die Prufung der Naturlichen Bausteine auf ihre Wetter-
bestandigkeit. Berlin, 190& W. Ernst und Sohn.

478 DETERMINATION OF PORE SPACE

RESULTS OBTAINED FROM PORE-SPACE DETERMINATIONS

Pore-space determinations have been made from 107 chunk samples
of oil and gas sands, cap-rocks, and shales collected from Pennsylvania,
West Virginia, New York, Ohio, Kentucky, Oklahoma, Texas, Louisiana,
Wyoming, and Montana. The distribution of diameter of grains of
36 of these samples have been determined. The pore space with density
and distribution of diameters of grains of oil- and gas-bearing sands and
associated rocks are given in the accompanying tables. None of the pay
sands in which oil was found that had a porosity less than 10.5 per cent,
were producing sands. The most probable explanation for this fact is
that there are sufficient fine grains, including cementing material, be-
tween the larger grains in these samples to reduce the interstitial openings
to a size sufficiently close to the subcapillary 11 size so that the oil, on
account of the resistance it meets under existing pressure and tempera-
ture, will not move rapidly enough to produce in commercial quantities.
A pore in an ideal sand, in which the grains are uniform spheres, does
not have a constant diameter throughout its length, but varies in diam-
eter and cross-section, passing continuously from a minimum to a
maximum cross-section.

Professor Slichter 12 has shown that the flow of water through a sand
may be reckoned as passing through an ideal sand, the pores of which
are continuous tubes of the minimum size. This reduction of the cross-
section of the pore to the minimum for the flow of the oil would make the
size of the pore approach much closer to the subcapillary than at first
it would appear from the diameter of the grains. On the other hand,
the grains of sand can be of such a shape and laid down in such a way that
the width, or diameter, of the pores at places are sufficiently close to the
subcapillary to interfere materially with production. The production
in such a case might not be sufficient for commercial quantities, even
when the well is repeatedly shot.

In Ohio, there are four wells of which production or non-production
are given. Plots of the sands of these wells are shown in Fig. 3, in which
the percentages, by weight, are plotted as ordinates and the diameters
of grains are plotted as abscissas. The depths of the sands from which
samples 5, 7, and 10 were obtained are about the same, the depth of the
sand from which sample 16 was procured is not given, but is probably
about the same as the others. Sample 10 has a pore space of 16.9 per
cent., the grains of its maximum column are larger in diameter than

11 A subcapillary tube is one in which molecular attraction extends across the
tube; the average size of such a tube, as determined experimentally by different
physicists, is about 0.00002 mm. in diameter.

12 C. S. Slichter: Theoretical Investigation of the Motion of Groundwater. U. S.
Geol. Survey, 19th Ann. Kept. (1899) Pt. 2, 305-323.

A. F. MELCHER 479

the grains of the maximum column of samples 7 and 16, and are about the
same diameter as the grains of the maximum column of sample 5. The
well from which sample 10 was collected had an initial production of
400 bbl. Sample 5 had a pore space of 13.1 per cent, and the well from
which this sample was obtained had an initial production of 80 bbl.
Sample 16 had a pore space of 16.8 per cent, and has its maximum column
at a much smaller diameter of grain than samples 5 and 10, and the well
from which this sample was collected had an initial production of 100 bbl.
Sample 7 had a pore space of 4.7 per cent, and its maximum column had
a small diameter of grain; the well from which this sample was taken
was non-productive.

RELATION OF PORE SPACE TO PRODUCTIVITY OF POOL

Pore space is undoubtedly one of the several factors that control
production from an oil or gas pool. Professor Slichter 13 also has shown
that if two samples of the same sand are packed, one sample so that its
porosity is 26 per cent, and the other sample so that its porosity is 47
per cent., the flow through the latter sample will be more than seven
times the flow through the former. If the two samples of the same sand
had been packed so that their porosities had been 30 per cent, and 40
per cent., respectively, the flow through the latter sample would have
been about 2.6 times the flow through the former. He states that
"These facts should make clear the enormous influence of porosity on
flow, and the inadequacy of a formula of flow that does not take it into
account."

Comparison of the production of one oil or gas pool with another
or of one oil well with another, from a comparison of their physical con-
stants and factors, is very similar to the comparison of two unknown
quantities, each of which is made up of an equal number of factors. It
is at once apparent that the more known factors there are of each, the
more nearly can they be compared or estimated. In this same manner
can the production of an oil or gas pool, or oil and gas well, be estimated
or compared, and the more factors known the closer can the production be
estimated or compared with a known production of a pool or well of
known physical factors. In three out of four samples where the quantity
of combustible matter burned out of the sample of sand amounted to 3
per cent, or less by volume, the well from which the sample was taken
produced salt water with the oil; see Table 1.

CONCLUSIONS

A method has been established that will determine the pore space of
very small fragments of oil and gas sands and determine the pore space
accurately. None of the pay sands in which oil was found, if the pore

* 8 C. S. Slichter: Op. tit., 323.

480

DETERMINATION OF PORE SPACE

<I 'A^JO ja^snQ '-OQ no nn H < < cococooscoo
pnug A-BJ pjojpBjg

A 'Ai '

00 O CM CO rtOSOOCOCO * O

rt CO rtCOCMrt

O CM

CO . t"

Ai -saMBQ eo -

jaAT^J I*OQ OS O CM O> Ol^-*t^O

rt (Nrtrt TjiO

iqg ooi noi* ^ N

a OAWOJp w g co co t co t os cort

_ pq 28 N ' * d SSrt M ' ^g

'puBg Bajag (91) ; ^

<M. IS a IW! r ! ^ J8 A ^

^oTo^'PFf^OAA "t ". 00 . C i .

WT^ J^Ji '* ! a eo Sc^S

SBQ puB no 1*a 3u TPI 8 IA S S

pag OTOJJ naraioadg -raiBj ioo S cocortocoOrt

^oqwapjan A\raaH aq no s o ' ; ^ ^ ^'os'ddd d

^ 1H CM CSCOrtrt iHO

OOf jo uot^onpojj CM co

^ TOOJJ ^uaraaBijj os * co os rtCM^ttoo cor-i

|oiqo 'raaiBsruaf '^oog "& '( co' rt CM co rt rtVcocirtrt'd o'd

uamlS 8A ^m P ^" U ai N T J t5 ** ^. ^ . N . C0 . N .

-asBqo raoj^'puBg Bajag (Z) ^ S wo cocoes coo

"iqa 08 uorpnpojj JBI^ o .,

&SVga2S -a -. -.-..-..-.- -o

A OTAAQFT * Tana A* /^w vr '^ CO ^H N C^ O CO ^J< C^ iH i-H fH O OO

Jd) rt * rt

'no :so 2 5

00 CO TjJ Tj| CO rt t- CM rt

I 8 3 CM d CM' co eiocoo'rt cod

*'' i-i

II 8 Ai nO QAi^onpojj raoj^ aid | rt g*^| :

-raBg -otqO 'Pt^^oOAi JB8 N -^-HNOS S ocoos coo

no 'i -o N w -^ co coco'^' o'd

raoi^ pug 9Jag (I) ^S" 310 ^^ ^2

iO rt S CO CM CN| 00 14 IO CO OO

BiadojaAaa ; d CM rt o'oo'wos'cM'rt eid

rt CM rt -^CMrt O

pUBg

-onpojj
-oj<j ui

' 8 II T W 8
-daqg no

puu

le M
of G

Per Cent., by Volume, of Comb
centage Distribution of Diam

Space

Total Po

TAB

-raj

3aipiatjt pag raojj
^UH JaN '
raoij puBg

"03 SBQ

A. F. MELCHER

481

DIAMETER OF GRAINS IN MILLIMETERS

.07* .104 .147 .208 .295 .417 .833 1.651

BEREA SAND , WOODSFI ELD, OHIO
Sa/np/e from tve// that produced oi/ and very /iff/e ^afc Hater

POROSITY w-.e

O .074 J04 .147 .208 .295 .417 .833 (61

BRADFORD PAY 3AND , PA..

POROSITY 17. a

KEENER SAND, WOODSFIELD, OHIO
aoropte from tve// tfiof-yi'e/dedgas. otfarrdsa/t nater
POROSITY 12..7

BEREA SAND, WOODSFIELD, OHIO
from weft fftaf- j

ITV 10. S

BEREA SAND, WOODSFIELD, OHIO
Samp/a from productive o/7 we//
POROSITY 11.0

DEVELOPERS OIL AND 6AS CO, FTrROLIA,TEXAS
POROSITY IS.S

' COAL RIVER NO. 4 DAWES .W.VA.
POROSITY 6.1

BEREA SAND.CHASEVILLE, OHIp
Sample from ncr>-producfir& n>e//
POROSITY 4.7

BEREA SAND. ARMSTRONG MILLS, OHIO

fhgmenr from Me// Hfr&r hod ' mMal 'production of/OO t

POROSITY 16.8

KEENER SAND, JERUSALEM , OHIO
/nifta/ product/on <4OOob&.
POROSITY 16.9

BIS INJUN SAND, LEWISVILLE.OHIO
/nitio/ production BO obis
POROSITY 13.1

COAL RIVER NO. I DAWES, W.VA.
POROSITY 4.8

IO4 .147 .206 .296 .417 .833 1.651

CABIN CREEK NO. 92 DAWES, W.VA.
' POROSITY IB. 7

.074- .104 .147 .208 .295 417 .833 1.651

COAL RIVER NO. 4 DAWES, W.VA.
POROSITY 19.7 i

FIG. 3. PERCENTAGE DISTRIBUTION OP DIAMETER OP GRAINS OP ELEVEN OIL-
BEARING SANDS, ONE NON PRODUCTIVE SAND AND TWO CAP-ROCKS.

VOL. LXV. 31.

482

DETERMINATION OF PORE SPACE

space was less than 10.5 per cent., were producing sands. A study of
samples 10, 16, 5, and 7 in Fig. 3, in connection with the corresponding
pore spaces and diameters of grains in the maximum columns of the
different samples suggests the conclusion that production is dependent
on both pore space and size of grains, other factors being equal.

Data already obtained indicate that results of physical experiments
involving the constants and factors stated in this paper are not only of
scientific value but can also be used in connection with the most efficient
methods of recovery of oil and gas; namely, in the valuation of oil and
gas fields, in the possible application of various methods of oil extraction
in fields where the normal flow is not sufficient to justify financially the
continuation of the well, in plugging off water, in spacing and rate of
pumping of wells, in avoiding interference of wells with one another,
in recognizing the nature and texture of oil-bearing beds, which will
respond to shooting, and where shooting will be detrimental.

TABLE 2. Total Pore Space with Density and Percentage Distribution

of Diameters of Grains of Gas-bearing Sands from Mexia-

Groesbeck Gas Field, Limestone Co., Tex.*

d g

,_,

d fl

5 g

g X

"o'

|'d

glrf

fl3

1*6

l^d

*ftz

C CQ

M^" 15

&~*

Pore space, per cent, by volume.

13.2

10.7

16.6

34.2

37.7

25.7

22.8

34.4

Total weight, in grams

0.847

1.557

0.310

1.258

0.843

4.766

0.845

3.274

Density of grains free from

moisture, or specific gravity

referred to water at 4 C. as

unity

2.76

2.73

2.70

2.68

2.73

Diameters from 0.833-0.417,

mm per cent

0.4

2.4

0.3

3.5

10 ft

417-0 295 mm., per cent

1.4

8.1

2.3

2.2

10.4

1U . O

20.1

0.295-0.208 mm., per cent

9.2

21.5

5.6

5.4

16.2

17.1

0.208-0.147 mm., per cent

33.3

29.2

39.0

38.9

26.6

13.6

0.147-0.104 mm., per cent.

40.1

29.2

40.2

42.0

25.3

14.1

1040 074 mm per cent . .

6.2

4.8

5.9

4.7

9.7

8.5

0740 000 mm per cent

9.5

4.8

6.6

6.4

8.4

15.8

Total

100.1

100.0

99.9

100. 1

100.0

* These samples were collected by Mr. George C. Matson.

In Table 2, the Clark No. 1 sample contains a small amount of iron.
The distribution of diameters of the Rawls, Clark, and Kendrick sands
was determined from a mixture of the two samples. The two determina-
tions of Clark No. 1 are duplicate measurements of the same sample.
Cargile No. 1 consists largely of very small particles cemented together;

A. F. MELCHER

483

nearly all of this material would pass through the 200-mesh sieve (0.074-
mm. diameter of grain) without breaking the particles. Kendrick
Nos. 1 and 2 contain a small percentage of cemented material, but the
remaining portion of Kendrick Nos. 1 and 2, and all of Rawls, Welsh,
and Clark, consist of well-defined individual grains.

TABLE 3. Total Pore Space with Density and Percentage Distribution of

Diameters of Grains of Gas and Oil-bearing Sands from Developers

Oil & Gas Co., Petrolia, Tex.*

fctfift -^rV'

Well No. 5,
Oil-bearing
Sand

Beatty Well
No. 1 Gas
Sand

Byerswell
Specimen
No. 1 Gas
Sand

Byerswell
Specimen
No. 2 Gas

Sand

Pore space, per cent, by volume
Total weight, in grams

18.5

17 725

21.7
8 522

26.6
22 798

24.9
19 897

Density of grains free from
moisture, or specific gravity re-
a f erred to water at 4 C. as unity
Diameters from 0.833-0.417
mm per cent.

2.65
2

2.64
01

2.66
01

0.417-0.295 mm., per cent

8 2

0.295-0.208 mm., per cent

45.8

23.0

0.1

0.208-0.147 mm., per cent

29 5

55 6

31.5

0.147-0 104 mm., per cent.

12 5

15 8

0.104-0.074 mm., per cent

1.8

2.6

9.6

0.074-0 000 mm., per cent.

2 7

8 8

Total

100.0

* These samples were collected by Mr. E. W. Shaw.

TABLE 4. Total Pore Space and Density of Grains of Oil Sands and Asso-
ciated Rocks from Butler and Zelienople Quadrangles, Pennsylvania*

No. 1

No. 2

No. 3

No. 4

No. 5

No. 6

No. 7

No. 8

Pore space, per

cent, by volume.

8.0

8.5

22.2

14.5

10.4

7.3

5.5

Total weight of

sample, in grams

48.281

14.840

5.770

9.331

21.994

9.637

9.811

6.493

Density of grains

free from mois-

ture, or specific

gravity referred

to water at 4 C.

as unity .

2.68

2.65

2.67

2.66

2.65

2.66

* These samples were collected by Mr. G. B. Richardson.

484

DETERMINATION OF PORE SPACE

In Table 3, the distribution of diameters of the Byerswell sand was
determined from a mixture of the two samples. Both samples of the
Developers Oil & Gas Co. Well No. 5, and Beatty Well No. 1, contained
a small quantity of magnetite. The Developers Well No. 5 consisted of
the largest size grains, a maximum percentage being of a diameter between
0.208 mm. and 0.295 mm. The Beatty sample gave a maximum per-
centage of grains between 0.147 and 0.208 mm. The Byerswell sand
consisted of the smallest grains of the three samples, the maximum
percentage being between 0.104 mm. and 0.147 mm, All three samples
consisted of well-defined individual grains.

TABLE 5. Total Pore Space in Oil and Gas-bearing Sands and Associ-

No. 1

No. 2

No. 3

No. 4

No. 5

No. 6

11 2

12 7

13 1

11 3

10.8
53.239

10 733

17 706

40.819

41 120

8 970

Density of grains free from moisture, or specific
gravity referred to water at 4 C. as unity

31.974
2 647

2.675

2 659

2 646

2 654

y 'Y
2 651

Diameters greater than 1.651 mm., per cent

20.4

O.d

Diameters from 1.651-0.833 mm., per cent

56 4

31.8

0.833-0.417 mm., per cent

14.7

45.2

0.417-0.295 mm., per cent

2.4

2.5

10.3

. 295-0 . 208 mm., per cent

8.3

29.4

1.7

5.0

0.208-0. 147 mm., per cent

48.0

50.6

13.1

53.3

1.6

3.6

147-0 104 mm per cent

36 8

26 1

63 3

10 1

1 i

1 7

104-0 074 mm per cent

4 9

3 7

8 6

1.7

.074-0 .000 mm., per cent

10.3

11.3

15.0

3.2

0.9

1.2

Total

100.0

100.1

100.0

99.8

Only one sample, No. 4, showed the presence of oil. It is quite certain that none
of the other samples belong to the oil-bearing sands.

No. 1, Fourth Sand, Speechley Pool. Concord Township, Butler Co., Butler
Quadrangle.

No. 2, Third Sand, Evans City Pool, Forward Township, Butler Co., Zelienople
Quadrangle.

No. 3, Snee Sand, Petersville Pool, Conoquenessing Township, Butler Co., Zelien-
ople Quadrangle.

No. 4, "Clover seed," Top of Fourth Sand, Haysville Pool, Fairview Township,
Butler Co., Butler Quadrangle.

No. 5, Fourth Sand (hard), Haysville Pool, Fairview Township, Butler Co.,
Butler Quadrangle.

No. 6, 100-ft. Sand, Evans City Pool, Forward Township, Butler Co., Butler
Quadrangle.

No. 7, 100-ft. Sand, Evans City Pool, Forward Township, Butler Co., Butler
Quadrangle.

No. 8, Fourth Sand, Haysville Pool, Fairview Township, Butler Co., Butler
Quadrangle.

A. F. MELCHER

485

No. 1. Berea sand; depth 2050 ft.; from Well No. 1 on the M. O. Huth farm near Woodsfield,
Center Twp., Monroe County, Ohio; fragment from a productive oil well.

No. 2. Berea sand; depth 1807-1829 ft.; from Well No. 2 on the N. H. Burkhead heirs farm near
Woodsfield, Center Twp., Monroe County, Ohio; hard densely cemented fragment from a Berea gas well.

No. 3. Berea sand; depth 1440 ft. sand sent by Larrick Bros, from Well No. 2, J. W. Steel farm,
near Chaseville, Sec. 26, Buffalo Twp., Noble County, Ohio; hard densely cemented fragment from a
non-productive well.

No. 4. Keener sand; depth 1539-1570 ft.; near the Huth farm, Woodsfield, Center Twp., Monroe
County, Ohio; from a bed that yielded gas, oil, and salt water.

No. 5. "Big Injun" sand; depth 1460-1470 ft.; well No. 2, A. C. Weber, Lewisville, Summit
Twp., Monroe County, Ohio; from a bed that yielded gas, oil, and salt water. Initial daily yield of
well was 80 bbl. of oil.

No. 6. Keener sand; depth 1220-1259 ft.; from well No. 5 on the G. W. Kysor farm near Coats
Station, Center Twp., Monroe County, Ohio; fragment of sandstone from a bed from which oil and
salt water were pumped.

ated Rocks, with Diameter and Density of the Component Grains *

No. 7

No. 8

No. 9

No. 10

No. 11

No. 12

No. 13

No. 14

No. 15

No. 16

4.7

9.7

11.0

17.7

14.5

18.4

10.5

11.0

13.0

11 3

14.7

17.1

12.4

15.0

15.9

17.4

16.238

14.090

5.765

41.482

19.693

8.446

28.591

5.057

3.819

1.956

36.412

60.867

4.309

28.900

43.213

30.979

2.665

2.727

2.705

2.653

2.649

2.647

2.649

2.662

2.731

2.658

2.698

2.682

0.8

1.9

23.5

0.2

0.8

41.1

34.4

2.6

8.5

16.6

47.2

30.1

78.9

70.8

18.3

3.4

5.1

12.4

4.6

12.9

30.3

0.3

13.8

2.7

3.6

2.6

29.6

3.2

28.8

25.4

36.0

11.2

1.7

1.4

30.1

18.7

1.4

20.5

0.4

54.3

38.2

37.6

11.0

1.0

0.9

10.0

48.6

1.0

10.1

56.8

11.4

9.6

26.0

12.0

0.5

0.4

10.3

12.6

0.4

4.1

20.0

2.9

16.2

36.4

15.4

0.6

0.3

0.6

15.5

20.1

1.8

6.2

22.8

5.8

100.0

99.9

100.1

100.0

100.1

100.0

100.1

* These samples were collected in Ohio by Mr. R. Van A. Mills and Mr. D. Dale Condit.

No. 7. Berea sand; depth 1535 ft.; Chaseville, Seneca Twp., Noble County, Ohio; hard, densely
cemented fragment from a non-productive well.

No. 8. Hard, bluish-gray shale overlying the Keener sand; depth 1445 ft.; J. R. Scott farm, Jeru-
salem, Sunsbury Twp., Monroe County, Ohio.

No. 9. Light bluish-gray shale, overlying the Keener sand; depth 1475 ft.; Hinderlong farm,
Miltonsburg, Malaga Twp., Monroe County, Ohio.

No. 10. Keener sand; depth 1451-1469 ft.; Well No. 2; J. R. Scott farm, Jerusalem, Sunsbury
Twp., Monroe County, Ohio; loosely cemented sandstone from productive bed, initial daily production
of oil from well was approximately 400 bbl.

No. 11. Berea sand; depth 1890-1920 ft.; Well No. 5; Henry Herdershot farm, Monroe County,
Ohio; fragment from productive bed; well yielded both gas and oil.

No. 12. Berea sand; depth 1500 ft.; McLaughlin Well No. 5; Chaseville, Seneca Twp., Noble
County, Ohio; fragment from productive bed; well yielded both oil and gas, with practically no salt
water.

No. 13. Gas sand; depth 1350-1355 ft.; George Reem-Schneider farm, Sec. 11, Malaga Twp.,
Monroe County, Ohio; fragment from a bed that yielded gas.

No. 14. "Big Injun" sand; depth 1460-1500 ft.; Well No. 1, Ben Butts farm, Lewisville, Summit
Twp.; Monroe County, Ohio; fragment from a bed that yielded oil and salt water.

No. 15. Berea sand; depth 2140-2160 ft.; Well No. 4, Taylor heirs farm, Woodsfield, Center
Twp., Monroe County, Ohio; fragment from productive bed; well yielded oil with very little salt water.

No. 16. Berea sand; Shepherd farm, Armstrong Mills, Belmont County, Ohio; fragment from a
productive bed; initial daily production of well was 100 bbl.

486

DETERMINATION OF PORE SPACE

TABLE 6. Physical Properties of Chattanooga Black Shale from the
Irvine Oil Field, Irvine, Ky. *

Pore Space, Per Cent,
by Volume

Total Weight of Sam-
ple, in grams

Density of Grains Free
from Moisture, or
Specific Gravity
Referred to Water
at 4 C. as Unity

Trial No. 1

7 6

34 646

2 57

Trial No. 2

7 4

45 670

2.57

* These determinations of porosity have been previously published. See Eugene
W. Shaw: The Irvine Oil Field. U. S. Geol. Survey Bull. 661-D, 190. Mr. Shaw
collected the samples.

TABLE 7. Total Pore Space and Density of Grains of Oil and Gas Sands
and Associated Rocks from Wyoming and Montana*

Name and Location
of Sand

Pore Space
Per Cent, by
Volume

Density of
Grains Free
From Mois-
;ure, or Specific
Gravity Re-
ferred to
Water at
4 C. as
% Unity

1. Wall Creek sand, Pine Mts., Wyo { i?! a | *

3.6

2.659

3.2

2. Peay sand, Stump triangle station, Big Horn f Trial 1

5.1

2.651

Mts 1 Trial 2

5.1

3. Wall Creek (Peay) S. S. Jack Creek, Mont

5.0

2.710

4. Torchlight S. S. about 2> mi. east of Grey- f Trial 1

28.6

2.634

bull, Wyo 1 Trial 2

30.1

28.9 ,

5. Wall Creek, S. S., Calcareous layer. From east side

Powder River House, Wyo., 10 mi. west Salt Creek. . .

7.6

2.675

f Trial 1

25.8

2.640

6. The main oil sand of Salt Creek field, Wyo. . \ ^ . } 1
[ l rial z

25.8

7. Shannon sandstone, % mi. northeast of town f Trial 1

26.9

2.667

of Salt Creek, Wyo 1 Trial 2

26.6

8. Wall Creek S. S., 10 mi. west of Salt Creek, f Trial 1

19.9

2.650

Wyo. Lower Ledge (full of cleavage planes) \ Trial 2

20.9

9. Peay S. S. Jack Creek, Mont I ^ r ! a } \

18.7

2.639

[ 1 rial 2

18.5

10 Peay S. S. Greybull oil field Wyo. j Tr ! a ! l

28.6

2.655

28.6

These samples were collected by Mr. Carroll H. Wegemann.

A. P. MELCHER

487

TABLE 8. Total Pore Space with Density and Percentage Distribution o]

Diameters of Grains of Oil- and Gas-bearing Sands and Associated

Rocks from Dawes, W. Va. *

Ohio Cities Gas Co.

No. 1
Coal
River
No. 1,

Rock

No. 2
Coal
River
No. 4,
Cap
Rock

No. 3 Coal River, No. 4 Pay
Sand

No. 4, Cabin
Creek No. 92
Pay Sand

Nr.5
Kelley
Creek,
W.Va.
Gray
(Wier)
Sand.
Only
Well on
this
Creek

Speci-
men 1

Speci-
men 2

Speci-
men 3

Speci-
men 4

Speci-
men 1

Speci-
men 2

Pore space, per cent, by
volume . . .

4.8
12.707

2.656

30.6
34.7
13.7
8.8

12.1
99.9

6.1
6.730

2.636

0.5
48.7
30.3

7.7

12.8
100.0

21.7
5.030

2.672

20.6
17.1
14.9

47.4
100.0

20.1
3.479

18.8
4.172

16.6
5.964

18.0
30.933

2.664

11.0
39.7
28.4
13.1
3.7

4.1
100.0

19.4
38.285

13.7
1.347

2.663

3.2
25.3
25.8
15.1

30.6
100.0

Total weight, in grams ... .

Density of grains free from
moisture, or specific gravity
referred to water at 4 C. as
unity

Diameters from 0.295-0.417
mm., per cent

0.208-0.295 mm., per cent. . .
0.147-0.208 mm., per cent.. .
0.104-0.147 mm., per cent.. .
0.074-0.104 mm., per cent.. .
Diameters less than 0.074
mm., per cent

Total

* These samples were collected by Mr. E. W. Shaw.

TABLE 9. Total Pore Space and Density of Grains of Sand from Bartles-

ville, Okla.*

(i)

Bartlesville
Pay Sand,
Bartlesville,
Okla., Skelton-
Moore Well
No. 11, Speci-
men 1

(1)

Bartlesville
Pay Sand,
Bartlesville,
Okla., Skelton-
Moore Well
No. 11, Speci-
men 2

(2)
Outcropping
Ledge of
Sandstone
From Same
Section,
Specimen 1

C2>,

Outcropping
Ledge of
Sandstone
From Same
Section,
Specimen 2

Pore space, per cent, by volume
Total weight, in grams

16.6

7.258

2.643

6.0
12.3
46.1
18.3
6.6

10.0
99.3

16.1

8.464

16.4
9.264

2.672

5.3
27.9
39.6
16.4
4.6

6.2
100.0

17.7
6.079

Density of grains free from
moisture, or specific gravity re-
ferred to water at 4 C. as
unitv. .

Diameters from 0.295-0.417
mm., per cent

0.208-0.295 mm., per cent.

0.147-0.208 mm., per cent
104-0.147 mm., per cent
0.074-0.101 mm., per cent.

Diameters less than 0.074 mm.,
per cent

Total

* These samples were collected by Mr. G. B. Richardson.

488

DETERMINATION OF PORE SPACE

TABLE 10. Total Pore Space and Density of Grams of Gas-bearing Sands
and Associated Rocks from Shreveport, La. *

Name and Location
of Sand

Pore Space,
Per Cent,
by Volume

Total Weight
of Sample, in
Grams

Density of
Grains Free
From Mois-
ture, or Specific
Gravity Re-
ferred to Water
at 4 C. as
Unity

1. Woodbine sand, Butler well

17 4

17 512

2 733

2. Tooke and Burke, No. 1

29 1

4 068

2 681

3. Pay sand, rare sample, Curtis No. 1 . .

24 3

1 942

2 647

4. Greenish shale, just above pay sand of
Curtis No. 1

22 6

1 628

2 717

5. Reddish shale, just above pay sand of
Curtis No. 1

870

2 769

6. Flournoy, No. 1

37 7

7 300

2 700

7. McCutcheon fee No. 1

22 2

4 752

2 691

8. Henderson and Hester, two deter- , .
minations, very fine sand, almost !
the appearance of shale. . .

31.1
32 6

0.808

772

2 725

9. Independent Ice Co., fee No. 1, close to
above

36 7

8 705

2 688

10. McCormick fee, Well No. 155

25 3

4 876

2 728

11. McCullough fee, No. 1 I ^

17.8

37.106

12. Stoer, fee No. 1

20.3
14 6

25.582
12 003

3.314
2 693

13. Vivian field, Conlay No. 5

22 5

2 776

2 640

14. May Oil Co. No. 3 on S. W. Gas &
Electric Co. No. 2. Two deter- (a)
minations '. (b)

28.5
26

2.313
3 897

2 591

15. Monroe gas pay sand. Smith Nos. 1
and 2

27 2

2 448

2.672

16. Stringfellow fee No. 2

9 4

3 647

2 705

17. Christian No. 4. . 1 [ a ]

9.6

1.160

((b)
18. Hodges ward 1, sample of shale, deep
gas sand

8.8
16.9

1.137
6.931

2.662
2.752

19. Sample of sandstone containing some
shale, same well as No. 18

19.7

23.348

2.673

20. Sample from same well as No. 18, dark
gray sand

23 7

11 812

2 716

21. Sample from same well as No. 18, light
reddish gray sand

20 4

15 520

2.654

* These samples were collected by E. W. Shaw.

After grinding until they passed through the 100-mesh sieve,
the samples were washed in petroleum ether. The sample that gave 7.6
per cent, porosity was washed twelve times; the other was washed
eighteen times A washing consisted of covering the sample with

A. F. MELCHER

489

petroleum ether, letting it boil for about 15 min., and then decanting
off the petroleum ether. Petroleum ether was again poured over the
sample and then poured off; the process was then repeated. The final
porosity of each sample was found to be 8 per cent.

The separated grains of the shale passed through the 300-mesh sieve.
A 3-gm. sample of the shale was passed through a 100-mesh sieve and
then boiled for 20 min. in concentrated hydrochloric acid. The porosity
determined from the powder thus treated is 8 per cent., the same as was
obtained by boiling in petroleum ether Another 3 gm. sample was
passed through the 100-mesh sieve and heated 20 min. in a Bunsen flame;
the porosity determined from this final product is 19.6 per cent. The
specific gravity of the powder thus treated is 2.59, and a solid cubic
foot of it would weigh 161.69 Ib. A cubic foot of the shale with the 19.6
per cent, of pore space emptied in the way outlined would weigh 130 Ib.

In Table 7, the second determination of sample No. 4 is known to be
slightly erroneous. The value, 28.9, is a weighted mean in which the
first observation is given a weight equal to four times the second. No oil
was found in any of the samples, when they were tested in the flame.

Two tests of each sample have been made. No indications of oil
were found by heating specimens 1 and 2 of pay sand No. 1 in a platinum
crucible.

After a fragment of the Bradford pay sand, Table 11, weighing 11.817
gm. was heated in a platinum crucible by a Bunsen flame until all organic
matter and moisture were expelled it weighed 11.330 gm. The volume
of the fragment equaled 4.255 G.XJ. If 0.80 is the specific gravity of the
oil, the volume of the organic matter (mainly oil) is 0.608 c.c. Then the
per cent, of the total volume of the fragment burned is 14.3. Taking
0.84 as the density of the oil, the per cent, of the total volume of the
fragment burned is 13.6.

TABLE 11. Total Pore Space and Density of Grains of Bradford
Oil-bearing Sand and Medina Sand *

Density of
Grains Free

Pore Space,
Per Cent.
by Volume

, Total Weight
of Sample, in
Grams

From Mois-
ture, or Spe-
cific Gravity
Referred to

Water at 4 C.

as Unity

Medina

sand, Niagara Gorge, Niagara,

(a)

7.8

24.363

N Y.

Two determinations

15 126

2 657

Bradfor<

I pay sand, Minaid Run Oil Co.,

18.0

19.850

Custer

City, Pa. Two determinations

1(6)

17.6

26.616

2.663

* These samples were collected by Mr. G. B. Richardson.

490 DETERMINATION OF PORE SPACE

DISCUSSION

R. VAN A. MILLS,* Washington, D. C. Changes induced in the sands
by drilling and operating wells have an important bearing on this paper ;
the porosities of sands and the sizes of grains and of pores change as the
wells produce. Reductions in porosity and sizes of pores are caused by
induced cementation, brought about through the infiltration of reactive
waters into the wells and through the breaking down of bicarbonates in
the oil-field waters incident to the liberation of carbon dioxide when
wells are drilled and operated. The resistance to flow increases and
the rate of production decreases as the sizes of the pores are reduced.
Account must be taken of these facts in order to establish valid relations
between the initial rates of production of wells and the porosities of.
sands that have undergone induced cementation.

The textures and bedding in sandstones are extremely variable and
it is doubtful if many of the lumps of sand collected from wells after
they are shot are truly representative of the pays. In many sands, the
porous, open-textured parts of the pays are so soft and friable as to be
disintegrated by shooting, so that most of the remaining lumps represent
hard, tight parts of the sands. The collecting of representative samples,
together with adequate collateral data, constitutes an important part of
the investigation outlined by Mr. Melcher.

W. M. SMALL, Tulsa, Okla. Has Mr. Mills any ideas concerning the
zone of influence within which this cementation would take place; would
it be more pronounced close to the bore hole and how far would it extend
into the rock?

R. VAN A. MILLS. That is a difficult question to answer at the
present stage of the investigation. The greatest deposition of carbonates
occurs within or close to the wells, but in some fields there is evidence
that the sands become plugged in this way at ^considerable distances
from the wells. Shallow pay sands are frequently calcareous throughout
considerable areas, but this may be caused by natural agencies similar to
those causing induced cementation. Some new wells in old fields reveal
induced cementation by carbonates several hundred feet from the nearest
old wells, but how general this may be remains to be determined. Photo-
graphs of lumps of sand shot and cleaned from old wells in Butler County,
Pennsylvania, were published in 'Geological Survey Bulletin 693. These
photographs show how thoroughly the sands were plugged by carbonates.

In parts of Ohio there is much evidence that declines in production
are due largely to induced cementation of the sands. This is indicated
not only by the examination of sands from the old wells, but by the high

* Petroleum Technologist, U. S. Bureau of Mines.

DISCUSSION 491

yields of new wells drilled among the old cemented wells. In one locality
where the old wells have declined to average yields of approximately
% bbl. per day, the initial rates of production of new wells, drilled within
300 ft. of the old wells, run as high as 50 bbl. per day. In many cases,
the wells in this field were abandoned, not because the oil was exhausted
but because the sands became so cemented that the oil would not pass
through. The Bureau of Mines is pursuing field and laboratory experi-
ments upon the removal of carbonates from the pay sands immediately
around old oil wells through the use of chemical reagents. These
experiments afford considerable promise of successful application.

R. VAN A. MILLS (written discussion*). The trend of modern
petroleum technology is to displace speculation by establishing facts
and relationships through which to interpret underground conditions.
Conditions in the sands, such as thickness and lenticularity, coarse or
fine textures, openly porous or tight sands, initial or induced cementa-
tion, 14 initial or depleted rock pressures, the presence or absence of
water are mapped as guides to the development and operation of fields.
Samples of sand from apparently barren beds penetrated by the drill
are examined to determine their possible productivity. Underground
conditions that change during the operation of wells, more especially
the changes in the textures of pay sands caused by induced cementa-
tion, and the movements and rearrangements of the fluids, such as the
encroachment of water, are closely observed and recorded on field and
office maps. More reliable criteria for the valuation of oil and gas
properties are being established; studies of the probable oil and gas
content of sands, together with the production records of wells, are being
supplemented by studies of the conditions or causes governing the rates
of production. In all of this work and in the operation and conservation
of individual wells, investigations like those outlined by Mr. Melcher
are of primary importance.

The United States Geological Survey Bulletin, 15 from which Mr.
Melcher has taken his Table 5, production data, and other field notes,
establishes the importance of correlating physical and chemical studies
of the reservoir rocks and contained fluids with the production histories
of the wells to establish relationships for practical application, but the few
production figures published are not adequate for the use Mr. Melcher

* Published by permission of the Director, U. S. Bureau of Mines.

14 The term induced is used to designate the deep-seated effects of man's activities.
The cementation of pay sands incident to the drilling and operation of wells is one of
the induced effects in oil and gas fields previously described by the writer. See U. S.
Geol. Survey Butt. 693, 44-55, and 98.

16 R. V. A. Mills and R. C. Wells: Evaporation and Concentration of
Associated with Petroleum and Natural Gas. U. S. Geol. Survey Bull. 693

492

DETERMINATION OF PORE SPACE

makes of them. They suggest broad relationships that the porosities and
sizes of pores bear to the initial rates of production from a few wells, but
these relationships might be more definitely established, in the Appala-
chian fields, by using the large collection of sands and accompanying
field notes and production data that the writer and others have contri-
buted to the Geological Survey.

FIG. 4. APPARATUS FOB STUDYING CAUSES AND EFFECTS OP MIGRATION OF OIL AND
WATER THROUGH OIL SAND. (Plate XXII, U. S. Bureau of Mines Butt. 175.)

In studying subsurface relationships, we are obliged to deal with the
summations of effects of many factors whose values are only relative and
rarely alike in different localities or at different depths in the same lo-
cality. Porosity and size of pores are among these factors. A minimum
porosity value, or a minimum size of pores, below which sands are non-
productive in one locality, need not necessarily apply in localities where

DISCUSSION 493

the bedding of the sands, the modes of occurrence of oil, gas, and water,
the viscosities of the oils, the gas pressures, the subsurface temperatures,
etc. are different. Consequently, it is imperative that various principles
and relationships be studied, in conjunction with porosity tests, through
adequate field and laboratory methods for each locality.

The writer supplements field work and porosity tests, such as Mr.
Melcher describes, by comparative studies of fluid movements through
sands arranged in steel tanks. The tanks are equipped with plate-glass
fronts, to facilitate observations and the making of photographic records
of experiments. Oils from different fields are used, the number of vari-
ables in each experiment is restricted, and the relative values of different
factors such as porosity, viscosities of oils, buoyancies of oils and gases in
water-saturated sands, expansive forces of compressed gases in sands,
capillary forces, and many other factors are definitely established for each
set of experimental conditions.

The importance of adequate field methods and notes in the collection
of samples of oil- and gas-bearing sands must also be emphasized. It
should be understood that a large proportion of the hard, densely cement-
ed fragments shot and cleaned from wells represent so-called shells,
breaks, and tight sand, rather than true pay sands. Many of the pay
sands are so granular and friable as to render lump samples exceptional,
but where lump samples of the "pays" can be obtained, they should be
collected before they have been exposed to the weather. It is good prac-
tice to collect several lumps together with loose sand from the same well
for comparison. Large proportions of the loose sands cleaned from shot
cavities in producing wells come from the relatively friable pays. The
textures of these loose sands furnish criteria for the identification of
lumps from the same parts of the beds. Care should be taken to differ-
entiate between loose sands from shot cavities and drill sludge, which is
unsatisfactory because of its pulverized condition.

Owing to the extremely variable nature of beds of sandstone, no part
or section of a sandstone may be regarded as truly representative of the
bed. But the average result of several porosity tests upon a carefully
selected multiple sample from the productive horizon in a well should
most nearly represent the porosity of the pay sand at that place. Ade-
quate studies of the variations in texture and porosity of pay sands, and
the relationships that these conditions bear to the occurrence and re-
covery of oil and gas can be made only through intensive field and labora-
tory work. Samples of the sands should be collected in conjunction with
detailed geologic studies of a field or by a resident engineer or geologist
during the development and operation of the field. But no matter how
the work is done samples of the pay sands, drill logs, and production
records from as many wells as possible should be obtained and applied
in each field under examination.

494 DETERMINATION OF PORE SPACE

To establish the relationships that porosity and size of pores in sands
bear to productivity, it is advantageous to collect samples of the non-
productive rocks for comparison with pay sands. Pieces of non-produc-
tive rocks are occasionally brought to the surface through the shooting
of dry holes; also pieces of the cap sands are sometimes ejected in shooting
the pays, but for the most part we must depend for these samples on
small fragments or chips, of uncertain origin, found in the drill sludge and
cavings cleaned out while the wells are being drilled. The use of core
drills for sampling oil sands and their associated rocks has long been con-
sidered, but the writer believes that a sampling device (working on the
same principle as the under reamer) that will break fragments from the
walls of a well as it is being drilled should prove advantageous to compan-
ies applying physical and chemical studies of oil- and gas-bearing rocks.

The period in the productive history of a well at which a sample of pay
sand is collected, together with the water conditions in the well, have
much to do with the physical and chemical qualities of the rock and the
relationships that these qualtites bear to production. The porosities,
sizes of pores, and chemical compositions of water-bearing pay sands fre-
quently undergo marked changes during the operation of wells. The
induced cementation of pay sands by carbonates is exceedingly common

Through the cooperation of Mr. C. W. Paine, of Ozark, Mr. George
Vandergrift, of Woodsfield, and other operators in that locality, the
writer has had the groups of Ohio wells, cited by Mr. Melcher, under sur-
veillance since the summer of 1914. The subsurface geology has been
studied in detail 16 and samples of the oils, gases, waters, and reservoir
rocks have been collected and examined periodically. Some of these
wells have now (April, 1920) ceased to produce because the pay sands are
plugged by inorganic deposits from the waters associated with the oil.
The porosities and sizes of pores in the pay sands around the wells have
been so reduced as to stop production. 17 New wells situated within 300
ft. of the old ones, and drilled after the old wells had been abandoned,
yielded oil at initial rates as high as 10 bbl. per day from the same sands;
apparently from the same pays, where they had not been plugged.

The causes and effects of induced cementation have already been de-
scribed. 18 To ignore them in studying the relationships that porosity and
sizes of pores bear to the productivity of sands may cause errors. For
instance, consider two of the sands represented in Table 1, which together
with the other Ohio sands cited by Mr. Melcher, were collected and ex-
amined in the preparation of Geological Survey Bulletin 693. The Berea

16 R. Van A. Mills and D. Dale Condit: Unpublished manuscript and maps in the
files of the United States Geological Survey.

17 Figures showing changes in composition and reductions in porosity and sizes
of pores will be presented in later papers.

" See U. S. Geol. Survey Butt. 693, 44-50 and 98.

DISCUSSION

495

sand, from Armstrong's Mills, was collected from an oil and gas well that
had been producing for ten years. The initial rate of production from the
well was 100 bbl. of oil per day, but in 1914, when the sample was collected,
the rate of production had declined to about 2 bbl. of oil with a little water.
Chemical and petrographic examinations of the sand indicate that it
has undergone induced cementation through the deposition of carbonates.
Judging from the high proportion of secondary carbonates in the sample
the original porosity may have been diminished 7.7 per cent, of the volume
of the rock. 19 The sizes of pores and the permeability of the sand have
undoubtedly been diminished since the well started to produce. Conse-
quently the porosity and sizes of pores in this sample can bear no valid
relation to the initial rate of production of the well. To interpret the
loss by ignition of this sample as a loss of combustible matter is erroneous.
As shown in the accompanying table, the sample contains 4.23 per cent.,
by weight, of C02 combined with calcium, magnesium, and iron to form
carbonates. Part of this C02 would probably be lost during ignition
of the oil and paraffin contained in the sample. If the hydrocarbons in
this sample were removed by ignition prior to the porosity measurements,
the value of the porosity measurements themselves were impaired through
the breaking down of the carbonate minerals, which constituted an im-
portant part of the sample.

TABLE 12. Analyses of Sands from Oil Wells*
(R. C. Wells, Analyst)

Keener Sand from Well
No. 2, J. R. Scott Farm
Per Cent.

Berea Sand from Well
on Shepherd Farm,
Per Cent.

SiO 2

93.82

85.90

Fe 2 O3 (all Fe as FezOs)

1 75

2 82

A1 2 O 8

0.73

1 68

CaO

2 96

MgO

0.25

0.84

P 2 O

CO 2

Trace

4 23

TiO 3

0.12

Loss on ignition less COj

2 31

1 35

99.19

99.93

* U. S. Geol. Survey Bull. 693, 17.

19 The calculation is based on the assumption that the sample, having a total
porosity of 16.8 per cent., contained 4.23 per cent, by weight of COa combined with
calcium, magnesium, and iron to form carbonates, and also that the sand was free from
carbonates when the well was drilled. The examination of a large number of samples
of water-bearing pay sands from new wells in new fields in Ohio, Pennsylvania, and
West Virginia reveals only traces of carbonates.

496 DETERMINATION OP PORE SPACE

The [Keener sand from well No. 2 on the J. R. Scott farm, near
Jerusalem, Ohio, though collected after the well had been producing for 1 1
years, apparently had not undergone induced cementation. The sand
contained only a trace of C02 and the well has remained the best pro-
ducer in the field. 20 The injury to the sand that necessitated shooting the
well was caused by so-called paraffining of the sand, and the high per-
centage of combustible matter in the sample was due to the presence of
waxy hydrocarbons, which reduced the effective porosity. The examina-
tion of this sample, after the hydrocarbons were burned off, furnishes
more reliable data for use in establishing the relationships that porosity
and sizes of pores bear to initial rates of production.

The relationships that total porosities of coherent sands may bear to
the rates of production, as well as to the ultimate productions from such
sands, depend largely on relationships between total porosities, effective
porosities, and sizes of pores. All of these conditions are related one to
the other and all of them influence the retentivity as well as the fluid
movements through sands. Cementation, either natural or induced, has
played a major role in reducing the total and effective porosities of lithi-
fied sands, but it has likewise reduced the sizes of the pores. The most
densely cemented, or in other words the least porous, of the lithified sedi-
ments generally contain relatively fine pores. In unconsolidated sands,
where there has been little cementation, the total porosities, effective
porosities, and sizes of pores are not so closely related. The writer's
experiments with unconsolidated sands indicate that sizes of pores, and
especially the sharp variations in the sizes of pores between different beds
or in different parts of the same beds, are factors of primary importance in
the movements of oil and gas through water-bearing strata, regardless of
total porosities. 21

The selective or differential permeabilities of sands to waters, oils
and gases are also of primary importance in recovery problems. These
selective or differential permeabilities depend not only on the porosities
and sizes of pores of the sands, and the viscosities, pressures, and tem-
peratures of the fluids, but also on the order and degree with which the
sands have become wet or saturated by water or .oil. Studies of these re-
lationships, especially the studies of effective porosity and of permeability
that Mr. Melcher proposes to make, constitute a new and promising phase
of petroleum technology in which real advances can be made only through
intensive field work supplemented by systematic and scientific laboratory
experimentation.

20 See U. S. Geol. Survey Bull 693, 97.

21 R. Van A. Mills: Experimental Studies of Subsurface Relationships in Oil and
Gas Fields. Manuscript in course of publication.

DISCUSSION 497

C. W. WASHBURNE, New York, N. Y. (written discussion). This
paper marks an advance in technical methods. The data indicate that
the oil-bearing parts of- sands are not more porous than the same sands at
their outcrops, a result that does not accord with the prevailing opinion
of many geologists, none of whom, however, has made such extensive
observations. The figures, though, should be regarded as minima rather
than averages, for the observations were made on coherent chunks of oil
sand obtained, probably, from the bottom of drill holes without the use of
core barrels. Chunks of this kind probably represent the harder, more
cemented, and less porous parts of the sand. The greater part of the
sand is more friable; it is ground up by the bit and comes out as sand, not
as fragments of stone. Chunks obtained from wells, therefore, are not
likely to be average samples of the sand.

To get the true average porosity of a sand, cores of the whole sand
should be obtained. The cores obtained by the core barrel on the Gulf
Coast are too fragile to ship, except in the core barrel itself. The efficient
field manager must study these cores before deciding how to case and tube
his well. He must therefore break them up immediately at the well. It
would give a truer figure of porosity if a method were developed whereby
the porosity of these cores could be determined in the field without inter-
fering with the driller 's examination.

VOL. LXV. 32.

498 WATER DISPLACEMENT IN OIL AND GAS SANDS

Water Displacement in Oil and Gas Sands

BY ROSWELL H. JOHNSON, M. S., PITTSBURGH, PA.

(New York Meeting, February, 1920)

ALL STRATA not yielding oil or gas in commercial quantities or a cor-
responding amount of water may be called dry in a wide sense. In
petroleum geology, however, we may exclude all sands of too low or fine
porosity to yield gaseous or fluid contents to the hole drilled in the sand
before any original pressure that its contents may be under is disturbed.
Most rocks are of this class and they are not reservoirs in our definition;
their "dryness" is wholly a matter of course. What are the contents
of the pores or what is the exact porosity of such rocks is of almost no
concern to us, for economically they are "dry."

What does interest us is the content of a rock having sufficient poros-
ity and the pores of sufficient size to yield oil or gas in commercial quan-
tities, if they were present under original pressure. Dryness of these
reservoirs is a matter of supreme practical importance. Three views
current as to such dryness seem, to me, to apply in a few cases only. It
is the purpose of this paper to give reasons for this position and for be-
lieving that, in ordinary sedimentary rocks, there is only rarely a reser-
voir of competent porosity and undisturbed pressure that is dry in the
sense of not yielding water, oil, or gas when first penetrated.

1. Gardner 1 writes of some Kentucky sands, "There has never been
present any salt water or other water in the sand." Absence of water
cannot demonstrate this position. It is necessary to show that the rocks
were not laid down in water, but in air, and that they became so enclosed,
while still above the water-table of the ground water, that water has not
been able to enter since. Most of these sands, and certainly the pro-
ductive limestones, were deposited in water; and such sands as have been
commercially productive show no reason for believing that the overlying
shale or limestone was not laid down progressively from one direction
and in water that would have flooded it. No adequate explanation has
been offered for this hypothesis, which is so inherently improbable.

2. Reeves 2 urges that "sands originally water filled may have been
drained of their water and not filled when later covered." It is difficult

i James H. Gardner: Kentucky as an Oil State. Science, N. S. (1917) 46, 279-280.

*F. Reeves: Origin of the Natural Brines of Oil Fields. Johns Hopkins Univ.
Circ., N. S. (1917) N. 3;

Absence of Water in Certain Sandstones of the Appalachian Field. Econ. Geol.
(1917) 12, 354-378.

ROSWELL H. JOHNSON 499

to see how the presence of the air could prevent the entrance of water
where the water overlaps the sand from one side and so has ample op-
portunity to expel the air. However, we have an excellent test of whether
the sand is dry because air filled, as supposed by Gardner, by merely ana-
lyzing this supposed entrapped air. Instead of the air called for by
Reeves' hypothesis we nearly always find methane. There are very rare
occasions where it is mainly nitrogen, probably entrapped air denuded
of its oxygen by the oxidizing of materials in contact. For these occa-
sions, as at Dexter, Reeves' hypothesis is helpful; but its unimportance
is measured by the extreme rarity of such cases.

3. Shaw holds that a sand may be adequately porous and hold water
and yet not yield it to a drill hole because of lack of expansive force
behind it. In view of the almost universal rule of an increase of pressure
with depth in our ordinary sedimentary strata, such as we find in oil
fields, such a failure must be excessively rare.

An absence of methane would not be expected in the sedimentary
series in which our oil and gas fields are found, because these rocks are
so generally charged with some gas, either free or dissolved in oil, in
some part of the reservoir. Even with no methane, we know that pro-
pane and butane are soluble in water to an extent of nearly 3 per cent,
so that they could give it expansibility for at least a short time.

DISPLACEMENT AND RESULTING MOVEMENT IN OIL AND GAS SANDS
Concluding, then, that the reservoirs now containing oil and gas
originally were water filled and that the gas and oil later entered the
reservoir, thereby displacing water, it becomes a matter of interest to
postulate the resulting movement of the oil, gas, and water, respectively.
We may assume that the oil and gas enter on all sides of the reservoir.
If at the bottom they would rise to the top, although in all probability
generally deflected en route along some bedding plane. Having reached
the roof of the reservoir, since this is ordinarily elongated and pitching,
they would move along the inclined plane until they formed an oil and
gas accumulation at the upper end.

The matter of especial interest to us is the action as it finds minor
dome-like irregularities. These will necessarily be filled if there is enough
oil and gas to fill them. If more than enough oil and gas reach these
local catchments, the oil and gas will resume their movement up dip.
However, as this movement continues, the proportion of the gas in
these catchments will increase. Indeed, the oil may nearly all be forced
down into the general stream and so move on up to the highest oil and
gas mass. In this motion upward along the crest of the reservoir, the
path would not be a broad one. Any " bulge" in the roof to one side
of such a "path" would not be fed with oil and gas, except such as
was caught by direct upward movement to it by side paths flowing

500 WATER DISPLACEMENT IN OIL AND GAS SANDS

on the way to the ridge. If the crest of the reservoir was very flat and
broad, we might possibly have a series of braided paths, such as one
finds in some rivers of broad bed. In the top mass of oil and gas to
which the paths lead, the percentage of oil to gas should be higher than
any bulge below because of the excessive proportion of gas held below.
This selective action explains some of the differences in relative per-
centage of gas and oil in different pools. Suppose now the reservoir as
a whole is arched, each flank is then working as before suggested but
the oil-gas mass is held at the crest instead of by the termination of
the reservoir.

So far as the upward motion of the oil -and gas has been discussed, we
have assumed that there are no obstacles to the free motion of any mole-
cule of oil and gas, as directed by gravitation. However, one serious
obstacle, surface tension, leads to the oil or gas rounding off into a bubble,
which thereby offers great resistance to motion in sandstone as fine as we
generally find it. A bubble forms in each "chink" between grains, but
its oil cannot move until the bubble grows so large as to extend as a
bud through one of the larger passageways into the adjoining chink
between grains. Only a continuous invasion can make progress. It is
a mistake to think of a passage of a series of bubbles as such. The
resistance in that case would be so great that gravitation at least would
be impotent except with very coarse deposits.

The water must have a motion away from the upper part of the reser-
voir as the movement of the oil and gas upward along the roof drives the
water, in part, back into the shale and, in part, down the reservoir to the
lower end. Again, we must consider the effect of depressions in the floor
(whether depositional or deformational) on the water as it recedes to the
lower end of the reservoirs. The water would fill each depression and spill
over its oil in the general movement down the reservoir. It retains a
disproportionate share of water after all the oil and water have passed
this depression going down dip. Some of the water may be forced out
through the floor of the reservoir, but it would usually leave the water
in excess until the gas accumulation was quite large. Therefore we
conclude that these depressions are less favorable points for oil and
that most of the oil will accumulate at the lowest part of the reservoir,
assuming that the displacement continues that long. The lowest part
of the reservoir being so frequently a matter of lateral variation or
" tailing" of the bed, this place is more difficult to locate. Hence the
search for oil in sands without water is more difficult than in those
carrying much water. It is not a case of mere reversal, seeking anti-
clines in one case and synclines in the other. Structure is, then, of still
less help in the waterless sands than would otherwise be supposed.

DISCUSSION 501

DISCUSSION

DAVID WHITE,* Washington, D. C. This is a most interesting point
concerning the genesis and distribution of oil, gas, and water in rocks.
According to common acceptance, a dry sand is one from which oil, water
or gas will not exude when it is penetrated by the drill or the mine shaft.
However, strictly speaking, there is no arenaceous sediment or clastic,
not excepting eoKan sands, which has not been laid down in water or has
not later been submerged beneath and filled with water before any sealing
cap-rock has been laid down. All sands have at some time been full of
water. . The expulsion of the water under varying conditions is a topic
not yet adequately discussed. It does not seem to have been generally
recognized that the essential reason why oil does not flow from the sand
when resistance is removed by perforation by the drill or the mine shaft
probably lies in the fact that former pressures have been reduced to the
point where capillary resistance prevents the outflow into the void.
There is one more question : Does the deformation occur while the oil,
gas, and water are in process of migration, or do these migrate after the
deformation occurs? Deformation takes a long time. The migration
also ought to require a long period. Is not the migration in progress
when the deformation is developed?

G. H. ASHLEY, Harrisburg, Pa. Within the past few months there
has been, in the McKeesport gas pool in western Pennsylvania, a develop-
ment that, if it has been properly interpreted, has some bearing on this
problem. The principal gas reservoir is the so-called Speechley sand,
found at a depth of about 2900 ft. (884 m.). Between 400 and 500 ft.
above that is the Elizabeth sand. The first big well contained too
much gas to be carried off by the 6-in. main that had been laid, so a valve
was placed in the main to allow the escape of gas above a pressure of
430 Ib. Mr. Tonkins, of the Peoples Gas Co., suggests that as a result
of the back pressure thus generated in that big well the gas from the
lower sand entered the upper, or Elizabeth, sand and enriched it, as
indicated by the fact that other wells put down to the upper sand have
increased their flow and later wells have obtained an enlarged flow from
that upper sand. If that is true, it indicates that the Elizabeth sand
was dry, not because nothing would flow out of it or into it, nor because
of closeness of grain, for otherwise the sand would not have taken up gas.

SIDNEY PAIGE, f Washington, D. C. You say the back pressure;
could the back pressure have been any greater than the original pressure
before the oil was tapped? How would this new movement have
occurred? It is not clear to me.

* Chief Geologist, U. S. Geol. Survey,
t Geologist, U. S. Geol. Survey.

502 WATER DISPLACEMENT IN OIL AND GAS SANDS

G. H. ASHLEY. Before the tapping of the lower sand, there was no
connection between the upper and lower sands.

SIDNEY PAIGE. It came up along the pipe?

G. H. ASHLEY. It came up along the pipe; there was no tubing or
piping between the sands. The 100-ft. sand was the last one that was
cut off.

R. H. JOHNSON. I should say that hydrocarbons are still coming in
while deformation is going on. The main reason for that is that the
deformation is particularly active in making hydrocarbons, as David
White's work has well shown. Most of the hydrocarbons must come into
the reservoirs quite a little later than was formerly thought.

May I add a point in connection with this well at McKeesport?
At the Elk City gas field, the other prominent gas field we have had
recently, the pressure started to decline at a rather rapid rate, but when
the pressure reached a certain point, the decline, although we were taking
out still more gas, was not so rapid. In explanation, it was said that the
well was tubed to a place above the productive sands, so that there was
an open hole of several feet. This sand, when first struck, I would suggest
therefore was feeding in there just as the Elizabeth was being fed at Mc-
Keesport, so the pressure dropped fairly rapidly during this period of
underground wastage; but after this sand had been fed to its capacity,
apparently the pressure declined more slowly. I suspect that something
very similar happened at McKeesport.

If we could have had pressures on that well right along, we could have
learned something about the feeding situation. The Elizabeth sand was
fed until it would take no more. From then on, of course, it was not as
serious a source of underground wastage except as the gas might go through
other wells than those of the owner.

These Elizabeth sands are not as large as they really ought to be,
considering the magnificent chance of being charged by this gigantic well,
which seems to be the result of a lower porosity. The sands yielded a
small amount of gas before this feeding process and the amount since is
only moderate compared with the great wells; I should say that was be-
cause it did not have the capacity to receive much of that gas.

E. W. SHAW,* Washington, D. C. In the Caddo, Elm Grove, and
Monroe fields, Louisiana, we have such extensive underground migration
of gas that after some of the big wells have been completed but not
successfully cased the country all around sizzles. The gas creeps from
one sand to another and sometimes blows out the surface as much as
}/ mile from the well where it left its natural reservoir.

* Geologist, U. S. Geol. Survey.

DISCUSSION 503

I do not see the bearing of this on the question of dry sands, concern-
ing which there seems to be a good deal of difference of opinion, for the
reason that when the gas rises from a lower sand, where the pressure is
high, to a higher sand, where the pressure is low, it is not essential, and
it is not to be inferred that the pores in the higher sand are empty or
even free from liquid contents. All that is required is that the gas or
liquid move off somewhere else or accommodate itself in smaller
quarters.

I was much interested in Mr. White's remark that we are all agreed
that pores are filled with something. If we can agree on this we have
made a real step in advance. The following step to be taken is longer
and more difficult, but it is a step that we must take sooner or later.
This step is to recognize that most dry sands are myths.

R. H. JOHNSON. The question of the helium in the Kansas and some
of the Texas gases, I think, has a bearing on Reeves' hypothesis of en-
trapped air. Those gases have more helium in proportion to nitrogen
than the air.

In this paper, I have accepted the notion that we might have entrap-
ped air to explain these nitrogen reservoirs. Since writing that, I have
become more skeptical. We can easily explain away the lack of oxygen;
that can be taken up to make carbonate, but why this super-atmospheric
amount of helium? These helium gases may have a deep-seated origin
over faults that do not come to the surface. May they not be gases of a
cosmic nature gases that have been extruded from original earth stuff
from still greater depths, that have worked along some faults and have
not been able to get closer to the surface?

Do not think that that means I am inclining toward any inorganic
origin of hydrocarbons, but if we do not accept that hypothesis, we have
difficulty in getting that much helium because the air rnust have been
entrapped, and it is utterly unreasonable to suppose there was more
helium in the air then than there is now. I dare say that higher up in
the air, there is a greater amount of helium, but that will not help us
because these gases were laid down close to the earth's surface, and the
gravitational contrast was as great then as it is now.

H. W. HIXON, New York, N. Y. That question of helium in the
gases goes back, I believe, to the origin of the hydrocarbons; and while
Mr. Johnson evidently does not believe in the inorganic origin of oil and
natural gas, I most decidedly do. If you assume that the earth had an
origin, it must have been either according to the planetesimal hypothesis
or a gaseo-molten condition. Taking the latter view, a planet above its
critical temperature is all gaseous. Under that condition, by applying
the law of the diffusion of gases, you have each gas occupying the whole
space of the body of the planet as if the other gases were not there.

504 WATER DISPLACEMENT IN OIL AND GAS SANDS

Gravitational compression will produce a condition of density greater
than that of the solids at sufficient depth, so that when such a planet
cools, the solid material, being lighter than the highly compressed gases,
will act just as if it were a solid throughout. You still have, in the body
of the planet, some of each of the gases that were present in the original
planet when it was all gaseous.

As regards the origin of petroleum and natural gas, there is just the
same reason for the hydrocarbons being in that gaseous interior as any of
the other gases. That is the reason why, from volcanoes, all the known
gases of the atmosphere and others are extruded. So the origin of helium
goes back to the original gaseous planet, like the origin of the hydro-
carbons. I take that stand, knowing that nearly all petroleum engineers
and geologists belie vet hat petroleum and natural gas are of organic origin.

I first became interested in this matter when I heard Mr. Eugene
Coste speak on the subject. He did not, however, go back as far as that
and simply denies that fossils or organic matter produce oil. I can see
how from the application of the law of diffusion of gases to a gaseous
planet, where all of these things would come about in that way, the oil and
gas would be entirely of inorganic origin. In the question whether the
dome is the cause of the accumulation of gas or the gas the cause of the
dome, I think you have the cart before the horse. I think the domes are
caused by the accumulation of gas, the gas causing the dome or the anti-
cline or both.

DAVID WHITE. The origin of the helium in such large amounts in
the natural gas of parts of Ohio, Kansas, northern Oklahoma, and Texas
is a geological problem of great interest and importance that is yet to
be solved, and it is greatly to be hoped that the oil- and gas-field geolog-
ists will find the key to the situation. There is some circumstantial
evidence pointing toward the occurrence of the helium-rich gas of Kansas
and Oklahoma over areas of deep-seated faults or disturbance. The
same may be true of the north Texas region. But the singular fact that
the helium now occurs, in general, in the shallow sands, and is present
only in relatively small amounts or not at all in the deep sands in most
areas is baffling. Apparently the Ohio area, Hocking and Vinton Coun-
ties, in which the helium is found in the Clinton as well as in the Berea,
offers no exception. One does not look for badly disturbed rocks in
the center of the basin in southeastern Ohio, although the unexpected
frequently happens, and it may have happened in this case.

COMPOSITION OF PETROLEUM 505

Composition of Petroleum and Its Relation to Industrial Use

BY CHARLES F. MABERY,* S. D., CLEVELAND, OHIO

(New York Meeting, February, 1920) "

So FAB as the elementary composition of petroleum is known, it
may be briefly stated. Petroleum consists principally of a few series of
hydrocarbons, with admixtures of sulfur, nitrogen, and oxygen deriva-
tives in comparatively minute proportions, which may be regarded as
impurities to be removed in the preparation of commercial products.
But as each series is represented by many homologs, in the aggregate,
crude petroleum is an extremely complex mixture of hydrocarbons and
their derivatives. In part, these hydrocarbons individually conform in
structure to the system of synthetic hydrocarbons whose structure is
well defined and represented by the typical series C n H2n+2, C n H2 n , the
series C n H2n-2, C n H2*_4, the members of which have not been suffi-
ciently studied to" establish their structure, and the series C n H2n-6 com-
posed of the aromatic group, benzene and its homologs. Hydrocarbons
of greater density contained in the portions of petroleum that cannot be
distilled without decomposition doubtless have less hydrogen than is
represented by these formulas. Since to every hydrocarbon there is a
definite temperature, even in vacuum, at which its constituent carbon
and hydrogen atoms fall apart, and since for the heavier bodies this tem-
perature is not much above 360 C. in vacuum, it is evident that some
other method than distillation must be devised for their separation if
anything further is to be learned concerning their individual constitution.

CLASSIFICATION OF PETROLEUMS

There is such a wide variation in the composition of petroleum from
different fields, it would seem possible to make a classification on this
basis were it not that no single variety is entirely free from hydrocarbons
contained in others. Such a classification has been suggested of the
exceptionally pure Pennsylvania petroleum, the sulfur oil from Trenton
limestone and other sources, the California oil with its large amount
of nitrogen (quinoline) derivatives, and the Russian oil, composed chiefly
of the naphthene hydrocarbons. 1 A commercial distinction is made

* Emeritus Professor of Chemistry, Case School of Applied Science.
*& F. Peckham: Jnl Frank. Inst. (1896) 141, 219; C. Engler: "Das Erdol,"
1, 228. Leipzig, 1913.

506 COMPOSITION OF PETROLEUM

between oils with a paraffine base, of which Pennsylvania crude is typical,
and oils with an asphaltic base, typical Texas and California crudes, the
heavier varieties; but this distinction cannot be sharply drawn since
there are oils that contain both constituents.

Both theoretically and commercially, there is a corresponding differ-
ence in quality between such light oils as those of the Appalachian fields,
some of them composed to the extent of 50 per cent, or more of gasoline
and kerosene hydrocarbons, and almost entirely of the hydrocarbons
CnHjn+2, including paraffine, and the Texas Gulf oils which contain no
hydrocarbons of this series but are composed of heavy members of
the series C n H 2n _2, and C n H2 rt -4, besides the still heavier asphaltic
bodies. But even here there is a connecting link in the hydrocarbons
of the series C n H2, 4 -2 that form the light lubricants of the Pennsylvania
oil. Such interrelations have been verified in all American petroleum.
From petroleum of many fields containing sulfur derivatives, such as
that of the Ohio Trenton limestone, of the Illinois fields and even
of Canada with large sulfur content, there are good yields of gasoline,
kerosene, and paraffine. The great fields of Oklahoma, Kansas, Wyom-
ing, and the lighter crudes of Texas and Louisiana with a variable com-
position between the Appalachian and the asphaltic crudes also fall
within this category.

Petroleum from oil territory in other parts of the world does not differ
materially in composition from that of the American fields. The princi-
pal foreign fields are those of Galicia, Russia, Rumania, Japan, and the
East Indian Islands. They contain, in variable amounts, paraffine,
gasoline, and kerosene hydrocarbons, but not of the same series as those
of American gasoline and kerosene. They all contain sulfur and nitro-
gen derivatives. Rumanian and Japanese oils are both composed to a
large extent of the naphthenes, to be more fully described later, as is also
Russian oil to the extent of 80 per cent, or more, in which these hydro-
carbons were first identified. Large amounts of Russian oil have been
sold here for medicinal purposes, but, no doubt, some varieties of
American petroleum are fully its equal in this field.

BASIC SERIES OF HYDROCARBONS

Referring again to the basic series of hydrocarbons alluded to above
as constituting the main body of American petroleum, the series C n H2n+2,
commonly known as the methane, or marsh-gas, series for it begins with
methane or, marsh gas, CH 4 , the principal component of natural gas,
is the most comprehensive for it includes the main portions of gasoline,
kerosene, and paraffine, and is often alluded to as the paraffine series and
its members as paraffine hydrocarbons. The latter increase in unit
order, by the increment CH*, through the more volatile gasolines with

CHARLES F. MABERY 507

boiling points from 30 to 150 C., C 6 Hi 2 to C 9 H 2 o, and next through
kerosene, with boiling points from 150 to 325 C., C 9 H 2 o to CigEUo,
when they soon begin to solidify as parafftne composed of the crystalline
hydrocarbons from C2oH 4 2 to C 5 H 7 2 and distilling in vacuum as high
as 350 C. In practical use, these hydrocarbons include paraffine for
candles, kerosene for illumination, and the lower members for motor
fuels, and various minor uses, such as cleansers and solvents. They are
extremely inert, entirely devoid of lubricating quality, easily decomposed
by heat (cracked) into lower members of the same series or into unsatu-
rated hydrocarbons. Such decompositions, which include also other
heavier hydrocarbons, are the basis of the numerous cracking processes,
in which heavy oils are converted into more volatile forms for use as
motor fuels.

ETHYLENE AND NAPHTHENE SERIES OP HYDROCARBONS

Continuing with our scheme of the hydrocarbons, the next paralle
series C n H 2n , the ethylene unsaturated series, is present in small amounts
in most petroleum. The oil that separates by dilution of acid sludge
is composed to a considerable extent of these hydrocarbons, for they are
dissolved by the acid in refining the crude distillate. It was formerly
thought that these bodies formed a large proportion of American crude
oil, but they have since been shown to be another series of the same
empiric composition and formula, C n H 2 n, but altogether different in
properties; they are cyclic, or closed-chain, hydrocarbons with the name
naphthene, proposed by Markownikoff, who first discovered them in
Russian petroleum. These naphthene hydrocarbons are probably present
in all petroleum to a certain extent, in small amounts in the light Appa-
lachian oils and in larger proportions in the heavy sulfur and asphaltic
varieties. They form a considerable part of light American gasolines,
and Russian burning oil of superior luminosity is composed altogether
of these bodies. Like the hydrocarbons of ,the methane series, they
are devoid of lubricating quality, but the lower members form good
motor fuels.

HYDROCARBONS HAVING SOME VISCOSITY

The next series of hydrocarbons, of the general formula, C n H 2n _ 2 ,
is found in all petroleum. Collecting in the fractions above 300 C. and
having some viscosity, they form the lubricants in Appalachian petroleum
that are prepared for sewing machines, typewriter machines, and for
other similar light lubrication. The higher members of this series are
also constituents of the heavy motor-car lubricants. Heavy petroleum,
in general, is composed to a large extent of these hydrocarbons; but
although in such general use, their structure has not yet been ascertained.

508 COMPOSITION OF PETROLEUM

HYDROCARBONS POSSESSING HIGH VISCOSITY

Next in order is the series C n H 2n _4, made up of hydrocarbons possess-
ing a high viscosity; C 2 5H 46 is one of them. These hydrocarbons form the
constituents of the best lubricants it is possible to prepare from petro-
leum. Heavy petroleum with an asphaltic base contains these hydrocar-
bons in large proportion, and lighter varieties in smaller amounts. With
boiling points above 250 C. in vacuum, the decomposition, when dis-
tilled with dry heat, is partly prevented by the use of steam in the still or,
better, by excluding air and reducing the boiling points by exhaustion
when these hydrocarbons may be distilled repeatedly with but slight
decomposition. Straight petroleum lubricants are, therefore, made up
mainly of a few viscous hydrocarbons of the last two series mentioned, and
they are graded by varying the mixtures to provide for the kind of lubri-
cation desired.

AROMATIC HYDROCARBONS

The last series of hydrocarbons in petroleum, concerning which any-
thing is definitely known, is represented by the general formula, C n H 2n _ 6
or the so-called aromatic series, beginning with benzene, C 6 H 6 . These
hydrocarbons are contained in all varieties of petroleum so far as known,
but in only minute proportions in light grades, such as those of the
Appalachian fields. Some heavier grades, especially those of California,
contain large amounts of the aromatic hydrocarbons benzene, toluene,
the xylenes, mesitylene, and naphthalene has been observed. But these
bodies are rather a detriment in petroleum to be removed in the processes
of refining. They are closely related to the cyclic naphthenes in struc-
ture, the latter partaking of the properties of both the methane, or paraf-
fine, series and the aromatic series. For instance, by the addition of
hydrogen, benzene unites with six atoms to form hexahydro-benzene
C 6 Hi2, and from the latter by proper treatment the six atoms of hydrogen
may be removed to form the same benzene. The same relation holds for
all the homologs of benzene and their hexahydro derivatives.

OXYGEN COMPOUNDS OF PETROLEUM HYDROCARBONS

Of the oxygen compounds of the petroleum hydrocarbons, phenols
are found in some heavy varieties, such as California oil, and the naph-
thene acids first discovered in Russian oil, which contains them in con-
siderable amounts, are generally to be found. But they have no
influence on commercial products for they are removed by proper
refining, although it is probable that they have something to do with the
formation of emulsions.

CHARLES F. MABEBY 509

NITROGEN BASES

The nitrogen bases, the quinolines, are contained in all petroleum, in
some varieties in large proportions; it has been estimated that some
California petroleums contain as much as 10 to 20 per cent.; but they also
are completely removed in refining. These bases are of especial interest
in their bearing on the origin of petroleum as indicating its evolution
from organic remains, animal or vegetable.

SULFUR IN PETROLEUM

Sulfur is the most undesirable impurity in petroleum, and it is pretty
nearly everywhere present, except in the Appalachian oils and in certain
heavy oils from shallow wells. In general, it appears that the proportion
of sulfur has considerably diminished as compared with the quantities
contained in the earlier development of oil territory. The largest pro-
portion that has come under my observation is 2.75 per cent, in the early
Humble crude, about one-third free sulfur in solution, nearly all that the
crude oil can hold, and two-thirds combined. Formerly, the free sulfur
often crystallized out in the tank cars during transportation; now the
amount in this oil is less than 1 per cent. Sulfur was first observed in
Canadian oil at Petrolia, which carried 1 per cent., next in Ohio Trenton
limestone oil in the late eighties, containing 1 per cent, or less; and more
recently in the fields of Illinois, Oklahoma, Louisiana, Kansas, and
Wyoming containing variable proportions below 0.5 per cent. In
combination with the hydrocarbons, sulfur derivatives are of the form
C n H 2n S, such as the individual Ci H 2 oS, unstable when heated in contact
with air, but distilled without decomposition in vacuum. Their struc-
ture is uncertain but probably cyclic with sulfur the connection link.
Since, as in Texas, where wells are often drilled through beds of sulfur
with which the oil has long been in contact, it is not difficult to understand
its mechanical solution.

In the ordinary refining of petroleum, sulfur is removed only in part,
necessitating the use of special methods for its removal to the extent that
it should contain not more than 0.05 per cent, in burning oil to avoid
SO 2 in the atmosphere of the compartment, and not in excess of 0.1 per
cent, in lubricants, to avoid corrosion of metals. Distillation over copper
oxide or metallic iron is the usual method of removal where the amount
of sulfur is large. The presence of combined sulfur in petroleum has
an especial interest to the geologist, for it is doubtless associated with the
primary formation of the heavier varieties. Such large amounts as
petroleum contain could not have had an origin in vegetable or animal
matter; it must have been the result of secondary changes, in which the
oil came in contact with beds of sulfur, the latter having been formed from

510 COMPOSITION OF PETROLEUM

sulfates in underground sulfate water by reduction of organic matter.
When heated with sulfur, the hydrocarbons readily give off hydrogen
sulfide and under proper conditions the sulfur combines with the hydro-
carbons. These changes no doubt explain in part the principal differ-
ence between the light oils of the Appalachian region, which have never
been in contact with sulfur, and the heavier varieties of the middle west
and south, which have always been associated with sulfate waters.
The former are nearly pure mixtures of hydrocarbons, the lighter individuals
predominating, and of the most stable series, such as is known to be
experimentally formed from the decomposition of vegetable or animal
matter, containing only small amounts of sulfur. Derived from vege-
table matter in the Appalachian region, far removed from the organic
remains of the ancient sea that left the great saline beds of the middle
west between the Appalachian and the Rocky Mountains and far away
from contact with the" sulfur or sulfates of those deposits, this petroleum
may be regarded as the typically pure product of vegetable organic decay
with exclusion of air.

The conditions were very different in the formation of the heavier
varieties of Ohio, Illinois, Oklahoma, and Kansas in the great sea bed
of this region. Concurrent with the decay of sea life yielding oil, or sub-
sequently it may be, and with an increase in temperature, came the action
of sulfur removing hydrogen, increasing the density of the oil and intro-
ducing sulfur in combination. This sharp demarcation between the
formation of the Appalachian and middle west petroleum is sufficient
to account for these differences in composition and properties. Changes
subsequent to the formation of Appalachian oil, of moderate temperature,
pressure, possible transference or infiltration through different strata in
many periods of decomposition, elevation and folding, all combined to
produce an oil unlike in purity that of any other field. The heavier
quality of Trenton limestone petroleum, doubtless due in part to its
origin from the same source as the lime rock, was increased by the action
of sulfur in the formation of the compounds it now contains.

For the original formation of California petroleum the records are
plainly written in the great beds of marine shell life, asserted by Doctor
Dickenson to be an adequate source of all petroleum in those extensive
fields. As in other oil territory of similar origin, most of this petroleum is
thick and heavy, lacking altogether the lighter constituents of deposits de-
rived from a vegetable source. It contains much sulfur, indicating that
this element had something to do in the formation of its heavy condition,
much nitrogen in the form of quinolines, and a large proportion of heavy
asphaltic hydrocarbons the asphalt base. That it contains much organic
matter not fully converted into the petroleum hydrocarbons is shown by
the maggoty condition of some of the oil pools. On the other hand,
there is evidence that this petroleum has been subject to none of the

CHARLES P. MABERY 511

secondary changes that have contributed to the clarifying effects of the
eastern deposits that it has been changed little, if at all, in the location
of its origin. A possible contribution to the formation of California
petroleum, and it may be to other petroleum, is suggested by what has
taken place in the Rancho La Brea asphalt pits, and the interesting
collection in the museum at Los Angeles of animal skeletons representing
all the extinct mammalian fauna of that region caught in those pits in
the glacial epoch that terminated 25,000 years ago after a probable dura-
tion of 500,000 years.

HEAVY OHIO OIL

Besides the varieties of petroleum already described, there is another
essentially different in its composition and quality, in fact almost a class
by itself. As Appalachian petroleum, composed of a pure mixture of
hydrocarbons, stands at the end of a series with the lighter individuals
predominating, so this oil may be regarded as the other end of the series,
also a pure mixture of hydrocarbons but of the least volatile end. It
has none of the gasoline nor kerosene constituents, none of thenaphthenes,
no paraffine nor asphaltic base. This Ohio oil is, doubtless, of more
recent origin than most other petroleum, and it has never been in con-
tact with sulfur. It has been found in three localities not far removed.
One is a depression on the Mahone River, in quartz sand 150 ft. (45 m.)
deep, the oil overlying a pool of brine and closely adjacent to large beds
of coal. Just when the commercial development of this oil territory
had begun, the entire area was flooded with water by a water company.

A second field of similar character is the ancient Mecca district, one
of the first in this country to be operated on a commercial scale on account
of its use as a natural lubricant. This oil has also been long known for its
medicinal quality. But since it contains neither gasoline nor kerosene
hydrocarbons its output has been much restricted. The greatly increased
demand for lubricants has again attracted attention to this oil, and it is
now being systematically pumped for the manufacture of high-grade
lubricants. The wells are shallow, 70 to 100 ft. (21 to 30 m.) deep, and
the oil is taken from a surface of brine.

A third field of the same general type is near Middlebranch, Ohio,
likewise in a shallow depression of a few hundred acres; the oil is here
reached in wells about 700 ft. deep, also above salt brine. For some time
this field yielded a large supply of gas, which is still utilized in considera-
ble quantity. Both these oils, like the Mahone, are of more recent origin
than those of other fields, and they have undergone no other metamorpho-
sis by the influence of sulfur or changes in location than the apparent
evaporation of the volatile end gasoline and kerosene hydrocarbons.
Thus in nature's laboratory through long periods of time this oil, com-

512 COMPOSITION OF PETROLEUM

posed of a few hydrocarbons of maximum viscosity, has been formed and
preserved, and now with proper treatment it yields lubricants of the best
quality it is possible to prepare from petroleum. Since the crude oil has
a viscosity of 3000 sec., a specific gravity of 0.90 at 20 C., and all the
hydrocarbons it contains, except 5 per cent, of the lighter end, having
marked viscosity, in the treatment of the oil in refining, it is only neces-
sary to select the hydrocarbons for the viscosity desired, without decom-
position, and to give the resulting oil a proper finish. The lubricant
value of this petroleum is explained by its composition. Containing none
of the paraffine hydrocarbons, none of the naphthenes, it is composed
chiefly of the two series C n H 2 n-2 and C n H 2 n-4, both of high lubricant
quality. As to the composition of the hydrocarbons beyond the range of
distillation without decomposition, nothing is known; these residues
still retain their viscosity without the ready formation during distilla-
tion of asphaltic products common to most heavy petroleum.

For a more complete resume of the composition, geology, occurrence,
genesis, and technology of American petroleum reference is made to a
paper by Clifford Richardson, 2 a paper by C. F. Mabery 3 and the most
complete work on American petroleum industry that has appeared, by
Bacon and Hamor. 4 In 1915, David White, 5 of the U. S. Geological
Survey, gave a very complete review of the data from extensive observa-
tions and their bearing on the relations in formation of coal and
petroleum.

PREPARATION OF COMMERCIAL PRODUCTS FROM PETROLEUM

There has been little fundamental change in the refining of petroleum
since the early days of this industry. The first stage in the process is
distillation, to separate the cuts, or distillates, that are to be used for
gasoline, kerosene, and lubricants. Until recently, these cuts were made
by specific gravity of the distillate at the end of the condensers; now
pyrometers set into the stills give a fairly good separation by recording
temperatures. To avoid the decompositions of outside heat alone, live
or superheated steam is now freely used within the still.

There is always a certain amount of decomposition products in the
distillates, besides the natural impurities in the crude oil, so the next stage
has always been to agitate with concentrated sulfuric acid, which removes
these bodies as a heavy acid sludge that is drawn off after standing some
time to settle. Another process, which has found limited use, consists

Jrd. Frank. Inst. (1906) 162, 57, 81.
'Mabery: Jnl Amer. Chem. Soc. (1906) 28, 415.

4 R. F. Bacon and W. A. Hamor: "American Petroleum Industry." N. Y., 1916,
McGraw-Hill.

' Jnl. Wash. Acad. Sci. (1915).

CHARLES P. MABERY 513

in agitating with liquid sulfurous acid, but this process has not been
generally adopted.

For the complete removal of the acid sludge and acid compounds in
solution, the next operation consists of agitation with caustic soda in
sufficient excess to neutralize the acid. Since a very slight excess of the
caustic causes an emulsion of the oil, this stage of the treatment demands
the best skill and care on the part of the man in charge of the treating
house, with the aid of the works chemist. It is not possible to work by
definite formula, because the wide difference in the distillates from crudes of
different fields requires varying amounts of caustic. The formation of
emulsions is, and always has been, the worst trouble with which the refiner
must contend, for it means loss of oil, besides the additional labor, and
a darkening of the finished oil through the application of heat, which
alone will break up an emulsion. In such oil emulsions, minute particles
of aqueous alkali are completely enclosed within films of oil and retained
almost indefinitely at ordinary temperatures. Washing the emulsion
merely increases its volume by the absorption of more water. On the
other hand, if caustic is not used in sufficient excess to remove the
sludge, there is danger of an objectionable color as well as an acid condi-
tion in the finished oil. There is more danger of emulsions in finishing
heavy distillates. In the last stage of refining, the dry oil is passed
through Fuller's earth to lighten its color.

PRODUCTION AND USE OF GASOLINE

At first, kerosene was the principal product refined from petroleum,
with a limited use of gasoline, as a solvent and for cleansing, and of the
heavy distillates. Later, with the adaptation of acetylene and the cheap-
ening of electricity for both city and country lighting, the demand for
kerosene diminished to such an extent that, just before the war, the refiner
informed the seller of gasoline that he must take a certain proportion of
kerosene with his gasoline. The use of gasoline had already rapidly
increased, on account of the adaptation of the stationary gasoline engine
for power; and when the economic efficiency of the gasoline engine was so
perfected that it could be used for motive power in the automobile and
a popular demand for motor cars was established, the consumption
increased to such an extent that the output of crude oil, although very
greatly enlarged, could not meet the demand. Then appeared numerous
attempts and many patents were obtained for the production of motor
oil by cracking the higher hydrocarbons into lighter oils that could be
used in motor engines.

Even now it appears that the production cannot keep pace with
consumption, and that, as reported, reserve supplies are being drawn
upon to maintain a demand that, in large part, serves no economic nor

VOL. LXV. 33.

winds, and si
and convenience
of coal and petrol

Next in imj
nomic application!
over another,
butes of matter,
in view in all mecl

CHARLES P. MABERY 515

prevent such friction and that is to avoid contact, but it is possible
of control within the limits of economic mechanical operation by the
insertion of a third body capable of bearing the moving weight. Such a
body is known as a lubricant and the lubricating materials are restricted
to solids, the softer metals, graphite and certain other unctuous sub-
stances like talc, and some oils and greases. A hard metal bearing on a
softer metal may be lubricated to some extent by the softer metal, but
the nearest approach to an ideal solid lubricant is pure graphite, which
forms a veneer on a hard surface, closing the pores and, by means of
its highly unctuous quality, reducing friction to the lowest possible
limit. Of oil lubricants, the undecomposed petroleum hydrocarbons with
impurities removed possess the best wearing quality. They lubricate
until the last molecule is used up. Certain vegetable and animal oils
have the requisite viscosity, but they are less stable, gum and corrode by
decomposition, and are inferior in durability.

In the preparation of petroleum lubricants, the grade must be se-
lected with reference to the work that it is expected to perform, first in the
cuts of the distillation and then in the combination of the hydrocarbons
for the quality desired. The principal means of control are specific
gravity, viscosity, and the heat quality, as represented by the tests of
flash and fire. As factors of safety, the fire tests and especially the flash
test, must be closely controlled in oils designed for motor-engine lubri-
cation and made to conform to established safety limits for water-cooled
engines 250 F. (120 C.) and for air-cooled engines 350 F. These tem-
peratures of the cylinders should be exceeded by the flash points of the
lubricant oils by at least 50 F. For steam cylinders, lubricants must
have a flash of 500 to 650 F.

The actual value of a lubricating oil is based on its viscosity the
peculiar quality of oiliness or greasiness that holds the molecules together
with sufficient force to maintain the pressure of the surfaces they hold
apart. The viscous quality is wanting in the paraffine hydrocarbons
C n H 2n+2 and in the naphthenes C n H 2n . It appears in the series C n H 2n _ 2 ;
and of the distilled lubricants, reaches its highest value in the series
C n H 2 *_4. In heavy crudes, such as those of Texas and California, the
lubricating quality ends with the distillates from the asphaltic residues,
and only partly appears in the paraffine residue of the lighter crudes. But
in the heavy Mecca oil, all but a few hydrocarbons of the first distillate,
not more than 5 per cent., are decidedly viscous, the viscosity increasing
rapidly and continuing throughout the entire mass of the oil, such that
the residue of vacuum distillation has an extremely high viscosity. Thus,
it is possible to prepare from this crude oil a wide range of lubricants;
beginning with the light oils needed for sewing machines and type-
writer machines, watch and clock oils, through the various grades of
motor-oil lubricants, heavy-engine and steam-cylinder oils.

516 COMPOSITION OF PETROLEUM

Next to the production of power in a motor car, the most important
detail in its operation, and one that is too much neglected, is lubrication.
Too often the car owner has not the slightest knowledge as to what sort of
lubricant is best adapted to his car; he uses what is given him or what he
is advised to use, which is often too low in viscosity. An oil that seems
very oily at ordinary temperature may become as thin as water when
exposed to the great heat of the cylinders. Excepting perhaps the lightest
cars, all others should be run on lubricants with a viscosity of at least 1000
to 1200 sec., Universal viscosimeter, and the oil should not be used until
it becomes too thin. There is doubtless greater unnecessary wear in
motor cars from lack of lubrication than from any other neglect.

Of the many annoyances in the operation of a motor car, one of the
most serious is the necessity for frequent removal of carbon from the
cylinders, on account of its interference with the passage of the spark
for the explosion and its deadening effect on the resulting power. De-
posits of carbon may be formed from the lubricant and from the gaso-
line. With the use of normal gasoline, a lubricant properly refined and
adapted to the size of the engine, to its load, and the conditions of its
use, it is safe to say that, with proper manipulation, smoking exhausts
should disappear and carbon deposits be reduced to a minimum, or easily
removed by such simple expedients as pouring gasoline into the engine
while hot.

The common use of too light lubricants in motor cars is poor economy,
as well as the use of the same grade in all cars, irrespective of their weight.
No doubt the quality of the lubricant as well as the quality of the gasoline
has much to do with carbonization. Cracked gasoline, consisting of
partly decomposed hydrocarbons, more readily escapes complete com-
bustion, sending forth dense fumes, a sure indication of excessive carbon
deposits. Yet with a sufficient excess of air and an adequate temperature
for complete combustion in the cylinders, even these hydrocarbons may
be completely burned, leaving behind little carbon.

An exaggerated importance is attached to what is termed "free carbon "
in motor lubricants, a misleading term, based on the differences in the
carbon residue of a loose method of determination, which consists in
evaporating the oil until a mixture of free carbon and hydrocarbons re-
main, the latter not completely expelled by heat in this manner. It is
assumed that the results indicate the comparative extent to which dif-
ferent oils form carbon in an engine. But on account of other elements
of operation, as well as the fact that carbon deposits consist to a con-
siderable extent of mineral matter, sometimes as much as 70 per cent.,
the tendency to leave carbon in analytical determinations has little
bearing on the comparative value of lubricants with reference to carbon
deposition. Some of the best lubricants, as regards carbon deposits in
the cylinders, give higher percentage of "free carbon" in the analytical
determinations than others that carbonize more freely in the engine.

DISCUSSION 517

UTILIZATION OF OTHER PETROLEUM SOURCES

With the present abundant and convenient supply of petroleum, it is
not yet necessary to earnestly cast about for other forms of bitumen as
sources of commercial products most in demand. But we are assured
that the great deposits of rich carboniferous shales in the west only await
a serious falling off in petroleum production to provide a practically
unlimited output of motor-engine and lubricating oils, not perhaps of the
equivalent value of petroleum products but good substitutes.

Closely related to petroleum as to their origin and oils they yield by
distillation, are certain other varieties of bitumen found in Colorado and
Utah Gilsonite and Grahamite. 6 These natural asphaltic bitumens
still contain a considerable proportion of volatile oils, the lighter portions
having evaporated during their slow formation from petroleum leaving
these brittle solids resembling coals. But unlike coals containing the
inorganic residue of their primary vegetable formation, Gilsonite and
Grahamite, owing their genesis through secondary phases to petroleum,
are free from all inorganic residues.

As recently as twelve years ago, petroleum that could not produce
kerosene, such as that of Texas and California, was of lower commercial
value and in demand only for fuel, or for a limited production of lubricants.
Very soon the rapid development of the automobile industry, stimulating
a demand for gasoline and, consequently, for lubricants, gave greater
prominence to the heavy crudes, both as a source of lubricants and of
motor fuels by cracking the higher hydrocarbons. But with production
pushed to the utmost, the older fields alone could not have prevented a
gasoline famine during the war, with serious results. When in 1917 the
English Admiralty was confronted by defeat within three months unless
it could halt the submarine destruction, the situation was saved by the
contributory influence of the great increase in the output of motor fuel
from the new fields of Illinois, Oklahoma, Kansas, Wyoming, and Mexico,
all but the latter yielding large amounts of normal gasoline. With
the material falling off in production of the Appalachian fields, the new
territory came in at an opportune moment to meet the demands of the
war and the great expansion of the automobile industry.

VALUE OF SCIENTIFIC WORK

Much of the loss in the early days of the petroleum industry due to
haphazard prospecting and drilling was later avoided by the scientific
investigations of geologists, especially by Hunt, Orton, Winchell, New-
berry, and Hoef er. From the prospector's point of view, the most impor-
tant of all was the theory of Hunt suggesting the storage of oil in an anti-

6 Mabery: Jrd. Amer. Chem. Soc. (1917) 39 2 , 2025.

518 COMPOSITION OF PETROLEUM

clinal and synclinal system, and referring the great rock pressure on oil
and gas to an extensive underground hydraulic system. In the later ap-
plication and expansion of this theory, the storage of oil in all the great
fields of the world was found to be in well-defined anticlines. When the
Trenton limestone was identified by Orton as the reservoir of the immense
deposits of oil in Ohio and Indiana, he established such an extended
system of anticlinal storage of gas and oil that the direction of the dip
could be traced with sufficient accuracy to direct the prospector in his
drilling operations. Furthermore, Orton identified the dolomitic nature
of the oil-bearing rock and, by means of outcropping rock formation,
indicated the underlying strata that could be relied on as sources of gas
and oil storage.

What geological science has done in placing the exploitation of petro-
leum territory on a practical and successful economic basis has its partial
counterpart in the results of chemical research. What is known con-
cerning the chemistry of petroleum is the result of independent investi-
gations carried on in the limited facilities of the chemical laboratory,
altogether unlike the opportunities of the geologist who always had the
advantage of unrestricted observations at fundamental sources. If,
in the early development of the petroleum industry, there had been estab-
lished a properly organized refinery with adequate funds and an adequate
working force to ascertain the complete composition of crude oil from
the producing fields then known, and to take up thorough investigation
of newly discovered territory as it came into commercial prominence, the
gain to the present and future industry would have been beyond calcula-
tion. Even now, before oil territory is too far exhausted and abandoned,
such an organization should place on record a great accumulation of facts as
to the constituents of petroleum concerning which little or nothing is known,
and which should incidentally be of service to the petroleum industry.

DISCUSSION

SAMUEL P. SADTLEE, Philadelphia, Pa. (written discussion). I
have read, with great interest, this discussion on the individual series of
hydrocarbons that are found to be represented in natural petroleums.
One of the subjects of very great practical interest is, what hydrocarbons
possess special viscosity. Doctor Mabery very properly calls attention
to the class of hydrocarbons that seem to be characteristic of the lubri-
cants prepared from Appalachian petroleum. These, he states, are
higher members of the series CH2 n -2- He does not particularize as to
which kind of hydrocarbons of this general formula he means. It is
obvious that they are not the hydrocarbons of the acetylene series, but
of what are termed unsaturated cyclic hydrocarbons, also possessing
this formula.

DISCUSSION 519

He calls attention to the hydrocarbons of the series CH2 n -4 as possess-
ing high viscosity. Here again, it is proper to understand that reference
is made to unsaturated cyclic hydrocarbons, as distinguished from alipha-
tic hydrocarbons, and he practically awards the whole value for lubricat-
ing power in prepared oils to hydrocarbons belonging to these series.

He specifically states also, on page 507, of the naphthenes, first
recognized in Russian petroleum, and now known to be present in most
American petroleums, that, "like the hydrocarbons of the methane series,
they are devoid of lubricating qualities. " This rather positive statement
of Doctor Mabery's is probably not a matter that is, as yet, univer-
sally agreed upon. The studies that have been made upon this subject
in recent years, largely by the aid of the "formolite" reaction, do not
as yet give conclusive evidence on this subject.

Engler, in his work on the chemistry of petroleum, says (1, 387):
"The controversial question as to which group of hydrocarbons are the
chief bearers of the viscosity, which has recently been especially studied
on the one hand by Nastjukoff, as well as Herr, who take the view that
the viscosity belongs to the unsaturated oils, and on the other hand by
Charitschkoff , who attributes it also to the saturated naphthenes, is not
yet definitely decided. That the unsaturated cyclic hydrocarbons of high
molecular weight are also highly viscous is settled beyond doubt, as is
conceded also by Charitschkoff. It is, however, not yet shown that the
high molecular saturated cyclic hydrocarbons are not also very viscous. "

On page 558, Engler quotes a series of relatively recent results by
Marcusson, which were obtained by the study of both American and
Russian oils. These results seemed to conform with the view of Charit-
schkoff, that the nonformolite-forming constituents (other than the
unsaturated cyclic hydrocarbons) are, not only in relative quantity but
in their viscous quality, the chief representative elements in the lubricat-
ing power, and these include the paraffins, the naphthenes, the
poly-naphthenes, and the olefines. Engler discusses these results of Mar-
cusson at some length, and calls attention to the particular care with
which the formolite reaction must be carried out to insure accurate
results, and intimates that many of the discrepancies in the results
of previous experimenters may have been due to the overlooking of
necessary precautions in the carrying out of this reaction, and apparently
expresses himself as satisfied with these latest results of Marcusson,
based on the use of formolite reaction.

To sum up, therefore, I would merely say that it is desirable to con-
sider this question as not yet so definitely settled as seemed to be expressed
by the statements of Doctor Mabery. These studies of the lubricating
oils and the relation of their composition to viscosity are, of course, of
the greatest interest and importance, but we must not draw sharp
deductions based largely on a reaction that may be carried out in such a
way as to give varying results.

520 COMPOSITION OF PETROLEUM

Doctor Mabery gives a very interesting account of the special class
of Ohio oils in which this viscosity is particularly developed.

He gives an outline of the general methods of preparing commercial
products from petroleum, covering the general methods of refining, the
production of gasoline in increasing amount by cracking processes,
although he does not refer particularly to the cracking methods used (in
which there is considerable variation) and takes up particularly the
matter of lubricants and their uses. Some notice might have been
given of the very large use of clay filtration, which is an important part,
particularly in the preparation of high-grade lubricants. Many of the
special grades of lubricants with an exceptional low cold test and conse-
quent availability for lubrication, under conditions of low temperature,
are prepared exclusively by these methods of filtration with fuller's earth
or special grades of clay.

B. F. TILLSON,* Franklin, N. J. The subject of lubrication received
considerable attention at the last annual meetings of the American Society
of Mechanical Engineers and of the Society of Automotive Engineers,
and interest in it seems to be spreading so that there is a tendency towards
coordination of research along the lines of what should be the properties
of a lubricant and a bearing in order properly to utilize a lubricant. The
opinion seems to be quite general that oil grooves in bearings are, in the
main, detrimental and, as far as possible, should be removed; if used,
the edges of the groove should be tapered so as not to form a sharp surface
that will wipe away the oil from the moving shaft or body that rests on
the bearing.

But I wonder whether there is not the same agreement that, in general,
high viscosities are not at all necessary properties of an excellent lubri-
cant, that the lower the viscosity of the lubricant it is possible to use,
the less is the frictional loss; that the internal friction of the molecules
moving in oils of high viscosities is a considerable power loss?

In general, the rule seems to be that the viscosity lessens as the tem-
perature increases; but some instances seem to indicate a reverse condition.
I have heard that waxes or paraffins with a low melting point that have
been separated and left in a refrigerator for some time become
liquid at lower temperatures; that some soaps, if left on a window sill in
cold weather, change from solid to liquid form. Do not such examples
indicate that research concerning the colloidal conditions of the elements
that form the oils we are using is greatly needed?

Further research may show that if they do not crack readily or deposit
their carbons, oils of much lower viscosities than the present practice in-
dicates may be used in both automotive and general mechanical
engineering design.

* Min. Engr., New Jersey Zinc Co.

DISCUSSION 521

CHARLES F. MABERY (author's reply to discussion). In reply to
Mr. Tillson's question, as to the relation of viscosity to the quality of
lubricants, and the influence of temperature, I think that oils with the
lowest viscosity to meet the frictional conditions should be selected.
The influence of temperature on lubricants does not receive the attention
it should. The great falling off in viscosity by even slight raise in tem-
perature is a direct measure of the loss in power of the lubricant to keep
the bearing surfaces apart.

In reply to Doctor Sadtler's question, the lubricant hydrocarbons
represented by the formula C n H2n-2, are not unsaturated in the same
manner as the acetylenes or ethylenes, and in only one or two instances
has the structure been made out. But evidently a double bonded struc-
ture is necessary to account for the smaller number of hydrogen
atoms. Concerning the series C n H 2w -4, these hydrocarbons are the least
volatile portions of petroleum that can be distilled without decomposition.

Doctor Sadtler alludes to my ommission of the use of fuller's earth
in refining. For some time I have been connected with the preparation
of low-test and high-viscosity lubricants, and have had abundant op-
portunities to become familiar with the usefulness of clay filtration in
finishing these products.

522 CARBON RATIOS OP COALS IN WEST VIRGINIA OIL FIELDS

Carbon Ratios of Coals in West Virginia Oil Fields

BY DAVID B. REGBB,* MORGANTOWN, W. VA.

(New York Meeting, February, 1921)

THE value of carbon ratios in determining the boundaries of possible
oil deposits appears to have passed the hypothetical stage. The theory
that the ratio of fixed carbon in pure coals is an invariable index of in-
cipient metamorphism in both surface and underground rocks and that
it may be applied in defining the limits of petroleum, advanced by David
White, 1 has been received with keen interest by many petroleum geolo-
gists. Detailed isocarb maps have been prepared of the Pennsylvanian
area of North Texas and Eastern Oklahoma by M. L. Fuller. 2 A similar
map of the coal-bearing area of West Virginia is given here. .

An isocarb 3 is a line showing an equal fixed-carbon percentage, pure
coal basis; the term has been proposed by David White to supersede a
less expressive nomenclature.

The term carbon ratio is applied to the percentage of carbon in pure
coal after water and ash have been eliminated. As a comparatively
small number of analyses have been made on this basis, it is usually
necessary to compute the ratio by dividing the fixed carbon of the proxi-
mate analysis by the sum of the fixed carbon and volatile matter of the
same analysis.

Many thousands of proximate analyses have been made by the West
Virginia Geological Survey, covering nearly every county in which coal
is found. Numerous others have been made by the U. S. Geological
Survey and the U. S. Bureau of Mines, but as uniformity of results is
best secured by adhering to one set of analyses, the tests of the West
Virginia Survey have been exclusively used.

* Assistant Geologist, West Virginia Geological Survey.

1 Some Relations in Origin between Coal and Petroleum. Wash. Acad. Sci.
(March 19, 1915) 6, 189-212; Late Theories Regarding the Origin of Oil. Bull.
Geol. Soc. Am. (Sept. 30, 1917) 28, 727-734.

'Relation of Oil to Carbon Ratios of Pennsylvanian Coals in North Texas. Econ.
Geol (November, 1919) 14, 536-542; Carbon Ratios hi Carboniferous Coals of Okla-
homa, and Their Relation to Petroleum. Econ. Geol. (April-May, 1920) 15, 225-235.

3 The term isocarb has been suggested by David White as more accurate than
the word isovol originally used by him. The termjsovolve, used by Fuller, appears
to be a corruption of isovol.

DAVID B. REGEB

523

In preparing the isocarb map, it has been necessary to use analyses
ranging from the Dunkard (Permo-Carboniferous) coals down to, and
including, the Pocahontas Group of the Pottsville (Pennsylvanian), as,
with certain exceptions, there is a progressive rise of strata from the
Appalachian geosyncline southeastward to the Alleghany Mountains,
where the coals disappear above the summits. The Dunkard coals,
being much different in character from those of the Pennsylvanian, have
been used in only one county (Tyler). With certain minor exceptions,
in each county analyses from the oldest coal seams available have been
employed, in order to secure the nearest possible approach to under-

OUTLJNE MAP
WEST VIRGINIA

SHOWINO

ISOCARB LINES

AMD

OIL AND GAS AREAS

ground conditions. In carrying out this rule two or more seams have
been used for different portions of several counties where the pitch of the
measures is large.

The table shows in detail the various coals used in preparing the m ap
few analyses of coals above the Pittsburgh have been employed.

ISOCARB MAP

The map shows the main productive oil and gas fields of the state,
together with isocarb lines for the coal-bearing area, as plotted from the
preceding data. The dots with accompanying figures show the approxi-
mate localities represented by each average determination. The average
carbon ratio falls below 55 in parts of Roane, Calhoun, Gilmer, Doddridge,
Lewis, and Harrison counties; this area lies just southeast of the Appala-

524 CARBON RATIOS OP COALS IN WEST VIRGINIA OIL FIELDS

chian geosyncline, the axis of which extends roughly from the southwest
corner of Pennsylvania to the Kentucky state line in the northern half
of Wayne County.

It is apparent from the map that the main oil pools lie within the limit
of isocarb 60, the most notable exceptions being the Cabin creek pool
of Kanawha and Boone Counties, the southwestern limit of which is
not yet fully defined, and certain pools in eastern Kanawha and Clay
Counties. Oil also occurs in quantity in Brooke County, of the northern
panhandle, where the carbon ratio is 62. Recent we Is are reported
from Mingo County near the point where isocarb 65 crosses the Kentucky
line. Gas occurs in several localities on the high side of isocarb 65 in
Raleigh, Fayette and Nicholas Counties; it has also been reported in an
uncompleted well in Northern Wyoming, where the average carbon
ratio is 69.

PROBABLE LIMIT OF OIL AND GAS

It would seem, from the record of numerous wells drilled on the high
side of isocarb 60, that dry holes or gas will be the main result of tests
in such territory (certain exceptions have been noted above) and that
wells drilled on the high side of isocarb 65 can hope for only occasional
occurrences of gas.

It would seem, from the map, that new production in the western
portion of the state is most likely in Wayne, Cabell, Putnam, Kanawha,
Mason, Jackson, Roane, Wirt, Wood, Marshall and Ohio Counties. In
some of these, however, the strata have not been sufficiently disturbed
to afford gravitational segregation of oil, gas, and water, and in various
regions of these counties where favorable synclines occur the sands are
known to be saturated with water, contrary to the general rule through-
out the state. In spite of these two unfavorable features, the writer be-
lieves that several new pools will be developed in some of these counties.

In the central belt, certain undeveloped portions of Nicholas, Braxton,
Lewis, Upshur, B arbour, and Marion Counties lie on the low side of
isocarb 60, so that production may reasonably be expected from some of
these. As the structure of this region is largely monoclinal, the main hope
of oil will depend on terraces. Inasmuch as there is a rapid southeast-
ward expansion of the Pottsville, Mauch Chunk, and Greenbrier Series
structure maps based on surface strata do not fully reveal such terraces
and their location cannot be made until sufficient holes have been drilled
to afford the necessary subsurface data.

COMPARISON WITH OTHER STATES

The researches of M. L. Fuller show that in both Oklahoma and north-
ern Texas the main producing fields lie on the low side of isocarb 55,

DAVID B. EEGER

525

Table of Coal Analyses and Carbon Ratios

County

Locality

Coal Seam
and Group

Number
of
Analyses

Volatile
Matter,
Aver-

a S

Cent.

Fixed
Carbon,
Aver-

Cent.

F. C.

F. C. -f V. M.

Nearest
Per
Cent.

Hancock

East
West
East
West
East
West
North
South

Northwest
Southeast
Northwest
Southeast

West
East

West
East
West
East
West
East
North
Central
South
North
South
North
South
Northwest
Southeast
West
East
West
East
North
South
Northwest

Southeast
Central
North
Central
South
West

West

j. Kittanning (Ca)
Pittsburgh (Cm)
Pittsburgh (Cm)
^ittsburgh (Cm)
Jniontown (Cm)
Washington (Cd)

Pittsburgh (Cm)
Little Pittsburgh
(Com)
No. 2 Gas (Ck)
No. 2 Gas (Ck)
Pittsburgh (Cm)
Brush Creek (Ccm)
Bakerstown (Ccm)
Pittsburgh (Cm)
[Jniontown (Cm)
L. Kittanning (Ca)
Pittsburgh (Cm)
L. Kittanning (Ca)
Pittsburgh (Cm)
Harlem (Ccm)
Pittsburgh (Cm)
Pittsburgh (Cm)
L. Kittanning (Ca)
Pittsburgh (Cm)
Pittsburgh (Cm)
Coalburg (Ck)
Pittsburgh (Cm)
Eagle (Ck)
No. 5 Block (Ca)
Eagle (Ck)
Campbell Creek (Ck)
Eagle (Ck)
Eagle (Ck)
No. 3 Pocohantas
(Cp)
Gilbert (Ck)
Sewell (Cnr)
Eagle (Ck)
Fire Creek (Cnr)
Eagle (Ck)
Fire Creek (Cnr)
L. Kittanning (Ca)
Eagle (Ck)
Sewell (Cnr)
Pittsburgh (Cm)
L. Kittanning (Ca)
Redstone (Cm)
L. Kittanning (Ca)
Pittsburgh (Cm)
L. Kittanning (Ca)
Pittsburgh (Cm)
L. Kittanning (Ca)
U. Freeport (Ca)
L. Kittanning (Ca)
U. Freeport (Ca)
Sewell (Cnr)
M. & L. Kittanning
(Ca)
Sewell (Cnr)
Sewell (Cnr)
L. Kittanning (Ca)
Eagle (Ck)
Sewell (Cnr)
Sewell (Cnr)

No. 3 Pocahontas

Gilbert (Ck)
U. Freeport (Ca)
U. Freeport (Ca)

3
15
6

7
1
3

5
1

3
4
8
2
43
5
56
2
8
21
2
6
14
7
13
6
9
5
3
14

4
5
23
5
16
18
17
24
29
7
3
12
5
10
18
10
5
43
12
6
1
8

15
9
7
6
17
1

1
4

37.91
34.20
35.92
38.40
37.07
34.27

38.79

39.82
40.02
39.29
38.53
37.20
33.43
37.45
39.36
30.47
36.47
33.90
36.62
35.81
38.24
41.92
34.52
41.84
34.99
34.05
40.06
31.22
37.31
34.98
34.92
30.45
31.29
17.90

27.84
23.31
29.29
20.56
28.25
19.29
35.33
33.43
29.10
39.68
37.02
38.36
35.36
36.90
30.77
37.01
29.90
27.25
29.49
22.05
24.81
32 14

30.35
26.59
32.47
35.45
30.07
26.96

19.85

29.73
18.46
15.50

53.00
56.08
55.17
50.97
53.07
47.92

49.33

46.83
55.42
55.81
51.40
44.12
42.75
52.50
45.29
57.53
54.86
49.83
55.73
49.70
53.53
51.08
53.41
49.49
56.95
56.10
51.48
63.09
55.73
57.55
59.27
63.06
62.44
76.13

63.61
72.76
65.02
77.37
66.61
75.42
53.97
59.74
65.73
51.78
56.02
54.35
51.78
55.63
56.85
55.19
58.96
62.52
59.42
70.20
68.18
55.63

61.80
60.84
54.08
54.04
62.08
66.77

66.48

56.21
68.64
73.46

58
62
60

57
59

54
58
58
57
54
56
57
53
65
60
59
60
58
58
55
60
54
61
62
56
66
59
61
62
67
66
80

69
75
70
79
70
79
60
64
69
56
60
58
59
60
64 :,,,
59
66
69
66
76
73
63

67
69
62
60
67
71

78
82

Brooke
Ohio

Marshall
Wetzel
Tyler

Pleasants
Wood

Cabell

Wayne

Putnam

Wirt

Ritchie ....

Doddridge

Monongalia. ......
Marion ....

Harrison ....

Lewis

Gilmer

Clay

Kanawha
Boone ....

Logan ....

McDowell

Raleigh

Fayette
Nicholas

Braxton

Taylor . . .

Preston

Tucker

Randolph
Webster

Greenbrier

Summers
Mercer

Pocahontas
Grant

Mineral

NOTE. Group abbreviations are as follows: Cd-Dunkard (Permo-Carboniferous) ; Cm, Monongahela-
Ccm, Conemaugh; Ca, Allegheny; Ck, Kanawha; Cnr. New River; and Cp, Pocahontas (last six
Pennsylvanian).

526 CARBON RATIOS OF COALS IN WEST VIRGINIA OIL FIELDS

there being important exceptions in the former and smaller deviations
in the latter state. In neither state are oil pools of importance noted
above isocarb 60. In West Virginia, however, many of the large pools
lie above isocarb 55, and some large pools occur above isocarb 60, while
gas extends to still higher limits. The occurrence of oil at high carbon
levels in the latter state is reflected by its quality, since it is generally
of higher Baume* gravity than those of the other states, and commands a
higher market price, indicating that the process of natural distillation is
more nearly complete.

DISCUSSION

JOSEPH T. SINGEWALD, JR.,* Baltimore, Md. The utility of geology
in locating and developing oil fields is as much negative as it is positive;
it is just as important and valuable to eliminate large areas in which you
cannot expect to find oil or gas, as it is to select certain smaller and
restricted areas in which you may expect to find it. The processes are
really the same. If the isocarbs are a criterion for eliminating large
areas as not being likely fields of oil and gas, they are of immense practical
value. We cannot always apply this criterion as we do not always have
coal seams in an oil and gas region. Although first announced in 1915,
for the Appalachian field, this criterion has since been tested only in
Oklahoma and northern Texas. The Pennsylvania State Survey is
now making an isocarb map of that state. West Virginia offers the best
opportunity for testing it, in that we have many more analyses of its
coals than those of other states. The map of Mr. Reger shows a distinct
line running northeast and southwest, southeast of which there are no
oil or gas fields. In Maryland we now have an opportunity to test this
method. The western boundary of the state lies to the east of the line
on Mr. Reger's map. They are drilling along the Potomac River and
are about to commence drilling in Garrett County, the extreme western
part of the state. Stratigraphically, one might consider conditions as
favorable there as in West Virginia and, at first sight, structurally they
might be considered more favorable, in that the structure is more pro-
nounced. The folding, thinking of it only in terms of the angles of dip,
would appear no more intense than in some of the western states. So,
if the degree of metamorphism is not taken into consideration, we might
be inclined to recommend drilling in Garrett County. But if the degree
of metamorphism is tested by the isocarbs we ought to say not to drill.
As yet, however, the theory has been tested in so few places that we
cannot say "Do not drill," with absolute confidence.

So much for the grosser application of the isocarbs in ruling out
certain areas as not being possible localities for the occurrence of oil and

* Associate Professor, Economic Geology, Johns Hopkins University.

DISCUSSION 527

gas. It seems to me that the theory might also be applied to great
advantage in more detail. Take the case of West Virginia, where we
have a great many analyses in individual counties. If we draw in greater
detail on a larger scale, the curves of isocarbs and compare the irregu-
larities in those curves with the physical and chemical character of the
oil, the theory may give us valuable conclusions as to the geologic his-
tory of the oil itself.

We know that a certain oil has certain physical and chemical prop-
erties, but we do not know to what extent that oil has its own
peculiar properties on account of the original composition of the material
from which it has been derived, and to what extent it has those porp-
erties on account of the geological history through which it has gone.
The details of the isocarbs would appear to have within them the pos-
sibility of throwing light on that subject. It is a line of investigation
worthy of more attention.

528 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

General Notes on the Production, Marine Transportation
and Taxation of Mexican Petroleums

BY VALENTIN R. GARFIAS,* NEW YORK, N. Y.

(New York Meeting, February, 1921)

PRODUCTION AND MARINE TRANSPORTATION

ALTHOUGH the work on which this paper is based was carried on by
the writer as Special Commissioner of the Petroleum Department of the
Mexican Government, the opinions expressed are only his personal views
for which the Mexican Government can in no way be held responsible.
Notwithstanding that the appointment covers all phases of the so-called
petroleum question, as the one question of immediate importance was
that relating to taxation, it was decided to devote all the time to this
phase of the work.

The present report has been divided into two closely related parts,
the first dealing with the production and marine transportation of Mexi-
can petroleum, and the second, with the Mexican taxation on petroleum
and its products.

The writer wishes to acknowledge the loyal cooperation rendered by
Mr. M. C. Ehlen, who had charge of the statistical work, and by Miss
S. Stern and Messrs. E. P. Heiles and J. E. Morrissey.

The aim throughout the work has been to pave the way for a thor-
ough understanding between the Mexican Government and the oil
operators and to present a true and clear statement of facts relating to the
questions at issue.

MEXICAN OIL FIELDS DEVELOPMENT

The salient features in the development of the Mexican oil fields may
be summarized as follows:

1901. First commercially productive well in Ebano field.

1902. Tehuantepec field came in; Diaz Government granted conces-
sion to Pearson & Son on practically all Federal lands along the Gulf of
Mexico.

1907. First producing well in the Furbero field.

1908. Dos Bocas well caught fire, advertising tremendous produc-
tivity of Southern oil fields of Mexico.

* Manager of Foreign Oil Department, Henry L. Doherty & Co.

VALENTIN B. GARFIAS

529

1909. Tanhuijo field, discovery well.

1910. Discovery of oil in Juan Casiano, Potrero, Panuco, and Topila,
placed Mexico as a leader in oil production.

1911. First shipment of Mexican oil made to United States, on
May 25.

1913. Alamo field of Penn-Mex Co. discovered.
1917. New Constitution of Mexico, establishing national ownership
of subsoil rights was enacted, May 1.

1917. Cerro Azul field discovered.

1918. Tepetate and Naranjos fields came in.

1919. Casiano, Tepetate, and Potrero fields went to water.

1920. Chinampa field showed water in August.

1920. Zacamixtle field came in on Oct. 8.

1921. Naranjos field showed water, Feb.

Table 2 shows the holding companies and subsidiaries at present
operating in the fields and marketing Mexican oils.

TABLE 1. Relative Daily Production per Well in Mexican and American

Oil Fields

Field and State

Producing
Wells

Drilling
Wells

Well
Locations

Abandoned
Wells

Production

Daily

Well
Daily

Mid-continent.
Oklahoma

47,574
9,693
2,694
13,708
3,252
15,692

13,975
512
8,796

71,101
17,302
14,178
868
9,357

1,691
2,814
488
368
462
49

66
55
932

246
252
116
381
422

594
1,159
333
113

184
4

10
7
13

115
147
75
181
66

[n 1913 7163 wells,
[n 1914 5607 wells,
[n 1915 = 6029 wells,
[n 1916 = 6017 wells
[n 1917 = 6542 wells

302,567
192,533
103,867
117,166
68,067
31,033

4,467
2,666
25,633

24,467
23,067
15.433
54,767
273,000

6.40
19.90
38.50
8.50
20.90
1.90

0.32
5.20
2.90

0.34
1.30
1.10
63.00
29.50

North and Central Texas

Gulf Coast

Illinois

Lima Indiana .
Lima

Appalachian.
Pennsylvania and New York.
West Virginia

South, East and Central Ohio
Rocky Mountain

California ...

Total

228,702

8,342

3,001

1,240,633

5.4

Mexico

(a) 61
(6)80
(6) 249

567

237,884
296,305
296,305

3900.00
3710.00
1190.00

1. The figures relating to the American fields are those for the month of June, 1920 , published by
the U. 8. Geological Survey.

2. The wells abandoned in the American fields are listed by years, as given by the U. S. Geological
Survey. The figures (567) for wells abandoned in the Mexican fields include the total abandonments
to date.

3. The well statistics for the Mexican fields (a) refer to conditions on June, 1919, as given by Boletin
del Petroleo: b) refer to conditions during December, 1919, as given in Oil and Gas Journal. The
number of actually producing wells (80) during December. 1919 is estimated.
VOL. LXV. 34.

530 PRODUCTION, TRANSPORTATION & TAXATION OP MEXICAN PETROLEUMS

TABLE 2. Foreign Companies y Producing and Marketing, at Present

Operating in Mexico

Atlantic, Gulf and West Indies S. S. Co.

Cia Petrolera de Tepetate.
Agwi Pipeline Co.
Agwi Refining Co.
Agwi Terminal Co.

Cities Service Co.

Cia de Gas y Combustible Imperio, S. A.
Cia Terminal Imperio, S. A.
Cia Emmex de Petroleo y Gas, S. A.
Empire Transportation and Oil Corpn.

Gulf Coast Corpn.

Lagunita Oil Co.

National Petroleum Corpn.

Southern Fuel & Refining Co.

Tampascas Oil Co.

Cia Mezicana de Oleoductos Imperio, S. A

Compania Terminal Union.

Hispano Mejicana Oil Co.
Hispano Cubana Oil Co.

East Coast Oil Co., S. A.
Southern Pacific Railroad.

General Petroleum Company of California.
Continental Mexican Oil Co.

Gulf Oil Corpn.

Mexican Gulf Oil Corpn.

Island Oil and Transport Corpn.

Antillian Corpn.

Capuchinas Oil Co.

Colombia Petroleum Syndicate, Ltd.

Cia Metropolitan de Oleoductos, S. A.

Cia Mexicana de Petroleo La Libertad, S. A.

Cia Petrolera Nayarit, S. A.

Esfuerzo Tampiqueno, S. A.

Island Refining Corpn.

Metropolitan Petroleum Corpn.

Interocean Oil Co.

U. S. Asphalt Refining Co.

Mexican Crude Oil & Asphalt Product Co.

Mexican Petroleum Co., Ltd.
Pan-American Petroleum & Transport Corpn.
Caloric Co.

Huaateca Petroleum Co.

Cia Naviera Transportadora de Petroleo, 8. A.
Tamiahua Petroleum Co.
Tuxpam Petroleum Co.
Chiconcillo Petroleum Co.
Doheny & Bridge.

National Oil Co.

National Shipbuilding Co.

Comalea Oil Co.

Cia Exploradora del Petroleo, S. A.

New England Oil Corpn.
Cochrane, Harper and Co.
Canada Mexico Oil Co.
France and Canada Oil Transport Co.
New England Exploration Co.
New England Oil Refining Co.

(See also Magnolia Petroleum Co.)
Pierce Oil Corpn.

Cia Mexicana de Combustibles, S. A.
Anglo-Dutch Interests.
La Corona Petroleum Co.

Chijoles Oil, Ltd.

Cia Mexicana de Petroleo La Corona.

Tampico Panuco Petroleum Co.
Mexican Eagle Oil Co., (Aguila).

Eagle Oil Transport Co., Ltd.

Oilfields of Mexico, S. A.
Scottish American Oil and Transport Corpn.

Southern Oil & Transport Corpn.

Fuel Oil Distribution Corpn.

Tampico Navigation Co.

Tampico Shipbuilding Corpn.

Tal Vez Oil Co.

Scottish Mexican Oil Co.
Sinclair Consolidated Oil Corpn.
Sinclair Gulf Corpn.

Sinclair Mexican Petroleum Co.

Freeport and Tampico Fuel Oil Corpn.

Freeport and Mexican Fuel Oil Corpn.

Freeport and Tampico Fuel Oil Transp.

Corpn.
Mexican Seaboard Oil Co.

International Petroleum Co.
Standard Oil Interests.
Atlantic Lobos Oil Co.

Port Lobos Petroleum Corpn.

Cortex Oil Corpn.

Atlantic Petroleum Producing & Refining Co.
of Mexico, S. A.

Atlantic Oil Co.

Panuco Boston Oil Co.

Producers Terminal Corpn.
Magnolia Petroleum Co.

Azteca Petroleum Co.

Cia Inversiones de Aztlan, S. A.

New England Fuel Oil Corpn.
Compania Transcontinental de Petroleo, S. A.

Panuco Excelsior Oil Co.

Vera Cru* Mexican Oil Co.
Penn-Mex Fuel Co.
Texas Company of Mexico.

Panuco Transportation Company of Mexico.
Tex-Mex Oil Co.
Tidewater Petroleum Co.

Tide-Mex Oil Co.
Union Oil Company of California.
Otontepeo Petroleum Co.
California Investment Co.

VALENTIN B. GAEPIAS 531

TABLE 3. Comparison of Mexican and American Standards for Measuring
Petroleum and Its Products

Volume Relations
1 U. S. barrel = 42 . 00 U. S. gal. 1 U. S. gallon = 231 . 00 cu. in.

= 5. 6145 cu. ft. = 0. 13368 cu. ft.

= 158. 985 U. = 3. 7853 U.

= 0.158985 cu. m. = 0.0037853 cu. m.

1 cubic foot = 7.4807 U. S. gal. 1 cubic meter = 1000.00 li.

= 0.17811U. S. bbl. = 35. 31445 cu. ft.

= 28 . 317 li. = 264 . 1775 U. S. gal.

6. 2899 U. S. bbl.
1 liter = 0. 03531 cu. ft.

= 0. 26418 U. S. gal.
= 0.0062899 U.S. bbl.

The American standard weight of water is taken with water at 60 F.; the Mexi-
can standard, with water at 4 C. (39.2 F.).

Volume Weight Relations of Water at 60 F.
8. 32823 Ib. per U. S. gal.
349.78566 Ib. per U. S. bbl.
Metric ton (2204.622 Ib.) per 6.3028 U. S. bbl.
Long ton (2240 Ib.) per 6.4039 U. S. bbl.

The specific gravities of oils are expressed in the Mexican and American standards
as follows :

Mexican Standard
Weight of volume of oil at 20 C.
Spec ic gravity = Weight of same volume ofVater at 4 C.

American Standard
Weight of volume of oil at 60 F.
ic gravity - Weight of same vo i ume of water at 60 p.

Density is the weight per unit volume.

The formulas for converting Baume* degrees into specific gravity at 60/60 F.
and vice versa, are as follows :

Baume- degrees = Sp . Gr . x * 6 o /60 F. ~ 13
Specific gravity

To convert specific gravity of oil from the American to the Mexican standard
multiply the specific gravity as shown on the American hydrometer by 0.001061
and subtract the result from the American hydrometer reading; vice versa, to correct
from Mexican into American reading, multiply the specific gravity shown by the
Mexican hydrometer by 0.001062, and add the result to the Mexican hydrometer
reading.

The coefficient of expansion per degree Fahrenheit for oils varies with the specific
gravity (60/60 F.) as follows:
. 67 specific gravity ......... . 000728 . 87 specific gravity ......... . 000419

. 72 specific gravity ......... . 000627 . 91 specific gravity ...... ... . 000392

. 77 specific gravity ..... ____ . 000540 . 96 specific gravity ......... . 000368

. 82 specific gravity ......... . 000470 1 . 00 specific gravity ......... . 000356

To ascertain the number of U. S. barrels of oil at 60 F. in 1 metric ton of 2204.622
Ib., divide the specific gravity at 60 F. into 6.3028; for barrels per long ton, divide
specific gravity at 60 F. into 6.4039.

532 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

TABLE 4. Relation Between World's and United States 1 Petroleum Pro-
duction and Mexican Production and Exports in Barrels of
42 U. S. Gallons

Year

World's
Production^

United States
Production

Mexican Production

Mexican Exports

Total

Per
Cent,
of
World

Totalt

Per

cent
of
World

Totalt

To U. S. A.t

Per
Cent,
to
U. S. A.

1901

167,434,434

69,389,194

41.4

10,345

0.006

1902

182,006,076

88,766,916

38.7

40,200

0.02

1903

194,879,669

100,461,337

51.3

75,375

0.04

1904

218,204,391

117,080,960

53.6

125,625

0.06

1905

215,292,167

134,717,580

62.6

251,250

0.12

1906

213,415,360

126,493,936

59.2

502,500

0.23

1907

264,245,419

166,095,335

62.8

1,005,000

0.38

1908

285,552,746

178,527,355

62.5

3,932,900

1.38

1909

298,616,405

183,170,874

61.4

2,713,500

0.91

1910

327,937,629

209,557,248

63.9

3,634,080

1.11

1911

344,174,355

220,449,391

64.1

12,552,798

3.65

893,709

1912

352,446,598

222,935,044

65.0

16,558,215

4.70

7,627,795

7,383,229

96.9

1913

383,547,399

248,446,230

64.8

25,696,291

6.70

20,915,928

17,809,058

85.2

1914

403,745,342

265,762,535

65.8

26,235,403

6.50

22,880,530

16,245,975

71.0

1915

427,740,129

281,104,104

65.8

32,910,508

7.70

24,279,375

17,478,472

72.0

1916

461,493,226

300,767,158

65.0

40,545,712

8.79

26,746,432

20,125,657

75.2

1917

506,702,902

335,315,601

66.2

55,292,770

10.91

42,545,843

29,933,516

70.4

1918

514,538,716

355,927,716

69.2

63,828,000

12.40

51,768,010

40,819,870*

78.9

1919

557,500,000

377,719,000

67.8

92,402,055*

16.56

77,703,289*

57,618,589*

74.1

1920

660,000,000

443,402,000

67.0 185,000,000

28.0

147,204,000

112,374,000

76.0

* Oil and Gas Journal.

t Boletin del Petroleo (Mexico City).

t U. S. Geological Survey.
Estimated.

TABLE 5. Summary of Mexican Oil Production, Exports, Stocks, and

Domestic and Field Consumption During 1917 to 1920 in

Barrels of 42 U. S. Gallons

1917

1918

1919

1920

Exports .

42 545,843

51,780,479

75,812,760

147,204,000*

Bunker fuel

12,746,927

2,336,768

1,890,529

Domestic consumption

9,218,491

14,098,766

33,000,000

Loss in refining

492,588

600,000

Total net production

55 292,770

63,828,326

92,402,055

180,204,000*

Field consumption and losses
Oil in steel storage

10 000,000

4,781,509
14,526,559

5,000,000
12,528,518

13,000,000

NOTE. 1917-1918 figures
from the Oil and Gas Journal.
Petroleum Department. 1919

taken from Boletin del Petroleo. 1919 figures taken
Field consumption for 1918 estimated by Mexican
figures also estimated.

Estimated.

VALENTIN R. GARFIAS

533

TABLE 6. Mexican Oil Exports from Tampico, Tuxpan, and Port
Lobos to Destinations in Barrels of 42 U. S. Gallons

1917

1918

1919

1920

Exports

Per

Cent.

Exports

Per
Cent.

Exports

Per
Cent.

Exports

Per

Cent.

32,537,821
13,516,337

70.6
29.4

37,176,008
15,849,998
3,739,390

65.5
27.9
6.6

44,092,135
17,166,714
20,070,993

55.0
21.0
24.0

89,909,213
18,786,904
44,579,183

58.7
12.2
29.1

Port Lobos

46,054,158

100.0

56,765,396

100.0

81,329,842

100.0

153,275,300

100.0

Destination:
United States

35,386,242
630,579
4,801,536
535,367

679,157
49,836

3,971,441

76.7
1.38
10.60
1.16

1.48
0.11

8.60

40,819,870
681,177
5,557,827
377,394
885,483
2,600,806

4,689,774
1,153,065

71.9
1.2
9.7
0.6
1.6
4.6

8.3
2.1

57,618,589
2,558,496
6,642,985
553,692
1,964,282
3,054,357
239,985
277,591
110,509
66,767

95,794
116,716

72,504
5,996,982
1,960,593

70.8
3.1
8.2
0.7
2.4
3.8
0.3
0.3
0.1
0.1

0.1
0.2

0.1
7.4
2.4

112,373,795
2,010,958
13,087,007
593,252
5,754,903
5,493,533
1,101,448
579,496
107,341
159,130
144,624
41,952
58,433
463,179
60,538
101,729
132,630
6,070,439
4,895,265
45,648

73.3
1.3
8.5
0.4
3.8
3.7
0.7
0.4
0.1
0.1
0.1
0.0
0.0
0.3

o.o

0.1
0.1
3.9
3.2

0.0

Canada

Central America
West Indies

Great Britain

Netherlands

France

Portugal

Mediterranean Ports.
Gibraltar

Malta ... .

Tunis

Eeynt

Algiers . . . .

Italy

Suez

Mexican coastwise .-.
Bunker fuel . . .

Local deliveries

46,054,158

100.00

56,765,396

100.0

81,329,842

100.0

153,275,300

100.0

TABLE 7. Mexican Oil Exports to United States Harbors from January
1917. In Barrels of 42 U. S. Gallons

1917

1918

1919

1920

Exports

Per
Cent.

Exports

Per

Cent.

Exports

Per
Cent.

Exports

Per
Cent.

Texas Ports

9,023,492
7,254,180
3,680,169
13,552,930
1,875,471

25.5
20.5
10.4
38.3
5.3

9,878,409
8,082,334
2,571,652
17,144,345
3,143,130

24.2
19.8
6.3
42.0

7.7

15,787,493
8,181,840
1,959,032
26,965,499
3,975,683
749,042

'
27.4
14.2
3.4
46.8
6.9
1.3

30,941,986
14,824,281
6,087,332
48,626,183
11,098,771
795,242

27.5
13.1
5.4
43.3
9.9
0.8

New Orleans

Florida Ports

New York

New England Ports
California

Total to United States

35,386,242

100.0

40,819,870

100.0

57,618,589

100.0

112,373,795

100.0

534 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

TABLE 8. Mexican Oil Exports by Companies from January, 1917,
In Barrels of 42 U. S. Gallons

Company

1917

1918

1919

1920

Standard Oil Group
Standard Oil Co. of New York |
Standard Oil Co. of New Jersey [

5,035,774

7,645,671

6 970,927

21,502,886

Transcontinental Petroleum Co. J
Penn-Mez Fuel Co

3 451 226

7 007 833

8 495 047

3 176 963

Cortez Oil Corpn

1 935,360

9,096,435

7,960,959

48,777

385,996

Magnolia Petroleum Co. (New England)..
Mexican Petroleum Co.
Huasteca Petroleum Co

12,236,388

11,708,109

12,651,974

29,280,421

Royal Dutch Shell and British Interests
Mexican Eagle Oil Co. (El Aguila)

8,567,299

8,583,258

12,570,492

17,266,692

La Corona Petroleum Corpn

524,626

2,895,587

Tal Vez Oil Co

24,368

98,896

398,889

504,993

The Texas Co

1,955,146

1,256,128

6,814,084

12,355,082

Sinclair Consolidated Oil Co.
Freeport & Mexican Fuel Oil Corpn

3,626,917

3,939,756

4,753,862

8,300,045

Gulf Oil Corpn.
Mexican Gulf Oil Co . .

1 121 236

1 734 191

4 574 520

10 573,622

East Coast Oil Co

3 390 939

3 398 459

4 639 513

5 542,820

Island Oil and Transport Corpn

6,212,915

12,410,323

Pierce Oil Corpn

636,469

1,253,133

977,730

2,312,039

Union Oil Company of California

1,622,131

2,002,453

68,811

Cities Service Co.
National Petroleum Corpn

258,894

543,791

489,159

792,050

New England Fuel Co . .

166 567

218 244

1,126,967

Cochrane and Harper

335 571

1,187,915

Inter-ocean Oil Co

619 056

492 511

635 296

438,754

293,719

400,094

National Oil Co

1,602,134

Atlantic Gulf Oil Co.
Compania Refinadora del Agwi

6,403,967

Total

42 545 843

51 766 116

80 701 780 *

146,489,120

* Includes 2,998,491 bbl. Mexican coastwise shipments that were consumed domestically, making
net exports 77,703,289 bbl.

VALENTIN R. GARFIAS

535

TABLE 9. Tank Steamers in Operation and Under Construction
Companies Exporting Mexican Oils

Company

In Operation

Under Construction

Number
of
Tankers

Total
Dead-
weight
Tons

Maximum
Tonnage
per
Tanker

Number
of
Tankers

Total
Dead-
weight
Tons

Maximum
tonnage
_Pefi
Tanker

Atlantic Gulf Oil Co

16
4
15

1
18
2

19
45
15
12

221,000
25,000
106,777
5,100
145,325
10,000
263,000
50,884

109,039
449.166
100,000
82,875

18,100
8,000
12,777

12,350
5,000

7,500

12,650
15,000
9,500
11,000

14
7

4
11

15
17

160,400
126,000

30,270
150,000

116,600

159,960
225,000
80,000
89,000

12,000
20,000

10,300
12,000

10,500

12,650
20,000
10,000
12,000

Eagle Oil and Transport

East Coast Oil Co

Gulf Refining Co

National Petroleum Corpn

Pan American Petroleum & Transp. . .
Pierce Oil Corpn*. . .

Shell Transport Co t

Sinclair Consolidated Oil Corpn

Standard Oil Group
Standard Oil Co. of N. Y.f

Standard Oil Co. of N. J.f
The Texas Co

Union Oil Company of California!. .

* It is acknowledged that the information on this table is incomplete.
t Only a small number of these tankers are in the Mexican trade.

PRODUCTION AND EXPORTS
Mexican and American Oil-measuring Standards

The standards for measuring oil in Mexico are based on the metric
system and so the weight of water, which is the basis for comparison with
oil, is taken with water at a temperature of 4 C. and the specific gravity
of oil is based on oil at 20 C.; the American standards are taken on the
basis of the relative densities of oil and water at 60 F. (17 C.). It is
therefore evident that oil having a specific gravity of, say, 0.982 under
the Mexican standards is not an oil of 0.982 specific gravity under the
American standards. In order to establish the relation between both
systems, Table 3 has been compiled; this gives the specific gravities and
Baume" degrees in the American standard and the corresponding specific
gravities in the Mexican standard, and also the volume-weight relation
showing the number of barrels per metric ton.

The Mexican Government levies the tax on the weight of the oil,
pesos-per-metric-ton basis, while the American operator sells the product
by volume on the dollars-per-barrel basis.

Relation between World } United States, and Mexican Production

A clear idea of the Mexican oil production and exports may be
obtained from Table 4 and Fig. 1, which show that for the first seven
years, Mexico's yearly production did not reach 1 per cent, of the world's
total; that the increase in production was gradual until the light-oil fields
were discovered, in 1910, from which date there has been a rapid increase,

536 PRODUCTION, TRANSPORTATION & TAXATION OP MEXICAN PETROLEUMS

until the Mexican production aggregates about 28 per cent, of the world's
total. The greatest portion of the Mexican production is exported, the
exports began in 1911 and reached an important amount in 1913. About
three-fourths of the exports go to the United States, in 1920 this amounted
to over 112,000,000 bbl. During 1920, the United States and Mexico
produced on an aggregate close to 95 per cent, of the total world's output.

1917

FIG. 1. MEXICAN OIL

1918

1919

EXPORTS, BY PORTS FROM WHICH EXPORTED, AND TOTAL TO
THE UNITED STATES.

Summary of Mexican Production

Table 5 gives an analysis of Mexican production, exports, bunker fuel,
stocks, and domestic and field consumption during the last four years.
It shows that production has increased three and one-half times during
this period, domestic consumption has likewise increased, while the
volume of oil stocks or in storage has remained practically constant . The
figures relating to domestic consumption, losses, and storage shown in
the table are admittedly only approximately correct.

The following table gives the storage capacity in the Mexican fields
during 1919 and in August, 1920:

STORAGE CAPACITY, IN U. S. BARRELS

1919 AUGUST, 1920

Steel tanks 26,355,000 31,455,000

Concrete tanks 275,000 275,000

Earthen reservoirs 22,005,000 22,060,000

Concrete reservoirs 865,000 860,000

Total 49,500,000 54,650,000

VALENTIN R. GARFIAS

The steel storage facilities of four of the large companies is as follows:

BARRELS

Mexican Eagle 7,120,000

Mexican Petroleum 6,500,000

La Corona 2,500,000

Transcontinental 2,200,000

537

Exports by Destination

Table 6 and Fig. 2 show that by far the greatest bulk of the oil ex-
ported from Mexico goes to the United States, South American harbors

1911 1918 1919

FIG. 2. MEXICAN OIL EXPORTS BY DESTINATIONS.

coming next; the balance of the exports, a comparatively small sum, go
to widely scattered ports in the West Indies, Great Britain, the Mediter-
ranean, and elsewhere.

The amount of oil used as bunker fuel is increasing at a rapid rate,

538 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

for the first six months of 1920 being about equal to the total for the
preceding year. The Mexican coastwise movements include oil shipped
from Tampico, Tuxpam, and Port Lobos to Mexican harbors and to the
Aguila company's refinery at Minatitlan. The harbor of Tampico still
retains the leadership in oil exports with 59 per cent., Port Lobos comes
second with 29 per cent., and Tuxpam third with 12 per cent.

The oil shipped to Puerto Mexico is refined at Minatitlan and thence
marketed in Mexico or foreign countries by the Mexican Eagle Oil Co.
A small amount of oil produced in the Tehuantepec region is likewise
refined at Minatitlan, it being difficult to differentiate between this pro-
duction and the crude from Tuxpam or Tampico, included under "Coast-
wise shipments. "

The yearly over-all exports from Puerto Mexico have been approxi-
mately as follows :

BARRELS BARRELS

1913 1,003,000 1917 1,401,000

1914 1,846,000 1918 1,010,000

1915 1,933,000 1919. 1,882,000

1916 1,536,000 1920 2,300,000 (estimated)

Table 7 shows that since January, 1917, most of the oil exports had
gone to New York, Baltimore, Philadelphia, and neighboring ports; over
one-half of the Mexican oil exported to the United States going to ports
on the Atlantic seaboard. The exports to Texas ports have aggregated
about one-fourth of the total exports to the United States, this figure
being kept more or less constant since 1917, while the exports to New
Orleans have gradually decreased from 20 to about 13 per cent. The
exports to Florida ports have likewise decreased from 10 to 5 per cent,
and those to New England ports have had a correspondingly gradual
increase. The exports to California harbors aggregate a fractional
percentage of the total and consist for the most part of about 5 to 15
shiploads during 1919 and the first half of 1920.

Exports by Companies

Table 8 shows that the Standard Oil group easily lead at the present
time, the Mexican Petroleum being second; the exports by the Anglo-
Dutch interests are third, but they have approximately only one-half
the exports of the first group of companies. A number of independent
companies exported from 8,300,000 to 68,000 bbl. each during the year
1920.

It is interesting to note that only about sixteen companies, or rather
interests, are at present exporting Mexican oil, the transporting and
marketing of Mexican oil being thus narrowed down to the well-estab-
lished oil interests.

VALENTIN R. GARFIAS

539

Exports by Grades of Oils

It is difficult to obtain figures of exports of Mexican oils by grades;
those on which Fig. 3 is based are more or less approximate. However,
this chart shows that the exports of light crude have increased tremend-
ously during the last eight months, and that there has been but little
increase in the exports of heavy crude, crude gasoline, and fuel oil. This
would seem to indicate that refinery facilities have not been increased
during that time, the increase in exports being primarily due to the larger
volume of the light crude now produced in the Chinampa-Naranjos-
Alazan pool.

1919 I9ZO

FIG. 3. TOTAL MEXICAN EXPORTS SINCE NOVEMBER, 1919.

COST OF TRANSPORTING MEXICAN OIL IN TANK STEAMERS

Tables 6 and 7 show that since January, 1917, from 70 to 76 per
cent, of the total Mexican exports have gone to the United States; in
fact, were Mexican coastwise shipping, bunker fuel, and local deliveries
excluded, the net percentage shipped to the United States harbors
would be well over 75 per cent.

Table 7 shows that over half of the exports to the United States go to
Atlantic seaboard harbors, New York harbor and vicinity leading with
43.3 per cent. Approximately one-fourth goes to Texas ports, 13.1

540 PRODUCTION, TRANSPORTATION & TAXATION OP MEXICAN PETROLEUMS

per cent, to New Orleans, the remaining 15 per cent., or so, is distributed
between the Florida and New England ports; the amount being shipped
to California is almost negligible. It is therefore evident that in studying
the cost of transporting Mexican oils in tank steamers, it is necessary to
analyze conditions governing the transportation between the Mexican
harbors and Texas ports, New Orleans, Florida ports, New York and New
England, and primarily between Mexico and these last two mentioned.

Net Carrying Capacity of Tank Steamers

The net carrying capacity of tank steamers plying between Mexican
and American ports has been compiled in Figs. 4 and 5, which show that
the larger tankers are being used between Mexico and New York and
New England harbors, the smallest being used for the short runs to

48,000
45,000

42,000

30,000
^ 7JOOO
24,000
j* ? 1,0 00
1 18^000
| 15,000

7- 12,000;

ifi

flS

iglg

'.?
i

1917 1918 1919 1920

FIG. 4. TRANSPORTATION OF MEXICAN OILS IN TANK STEAMERS; NUMBER OP TANKERS
PER MONTH AND AVERAGE NUMBER OF BARRELS PER TRIP TO ALL PORTS.

Texas and Florida ports. Somewhat larger tankers are used from Tam-
pico to New Orleans.

In a general way, it may be stated that the average tanker plying
between Mexican harbors and New England or New York is a 10,000-
deadweight-ton tanker or larger, able to carry 60,000 bbl. and more per
trip; that the average tank steamers plying to New Orleans have a dead-
weight tonnage of about 8000 tons with a carrying capacity of about
45,000 bbl.; the smaller tankers of 3000 to 5000 tons and oil barges make
the run between Tampico and Florida and Texas ports.

Fig. 4 gives the average number of barrels transported per tank-
steamer-trip and indicates that this has increased from about 28,000 in
January, 1917, to 49,000 in October, 1920, showing that larger units
are being constantly put into service. This figure also shows that the
carrying capacity decreases during the winter months.

VALENTIN R. GARFIAS

541

9QOOO

1917

1918-

1919

.19EO

FIG. 5. AVERAGE NET CARRYING CAPACITY PER TANK STEAMER TRIP FROM MEXICAN

TO AMERICAN PORTS.

Distance from Tampico to American Ports and Time Required for Round

Trip

The distance from Tampico to American and other ports and the
average number of days required to make a round trip by a tanker, with
an average speed of 10 mi. per hr., allowances being made for days lost
in repairs, dry-docking, etc. are as follows:

Antofagasta, Chile 3,668

Baltimore, Md 1,951

Bayonne, N. J . 2,030

Beaumont, Tex 475

Boston, Mass 2,276

Buenos Aires, Argentine . 5,518

DISTANCE, TIME,
MILES DATS

38
24
25
12
27
54

Callao, Peru 2,874

Canal Zone 1,485

Freeport, Tex 474

Fall River, Mass 2,131

Galveston, Tex 473

Houston, Tex 473

DISTANCE, TIME,
MILES DAYS

32
20
12
26
12
12

542 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

DISTANCE, TTMB, DISTANCE, TIME,

MILES DAYS MILES DAYS

Jacksonville, Fla 1,361 19 Philadelphia, Pa 2,000 25

Key West, Fla 907 16 Pt. Arthur, Tex 473 12

Kingston, Jamaica 1,252 19 Portland, Me 2,275 27

Liverpool, England 4,905 49 Providence, R. 1 2,131 26

London, England 5,201 51 Rio de Janeiro 5,417 53

Marcus Hook, Pa 2,000 25 St. Thomas, W. 1 1,905 23

Maurer, N. J 2,025 25 San Francisco, Calif 4,150 42

Miami, Fla 1,048 16 Savannah, Ga 1,439 20

Mobile, Ala 721 15 Southampton, England . . 5,013 50

Montreal, Canada 3,301 37 Sparrows' Point 1,950 24

New Orleans, La 721 15 Tampa, Fla 921 16

New York 2,030 25 Texas City, Tex 475 12

Norfolk, Va 1,829 23 Valpariso, Chile 4,144 42

Pensacola, Fla 759 15 Warner's, N. J 2,025 25

The shortest trip, to Texas ports, requires an average of twelve days,
while fifteen days are allowed tankers making the New Orleans route.
The round trip to New York harbor and vicinity requires twenty -five
days; for the New England ports one or two days more are needed.

Cost of Tank Steamers

In pre-war days, the price of a 10,000-ton tanker averaged close to
$70 per ton; some of the larger oil companies purchased these steamers
for less. During the war, the price reached $200 per ton and higher; but
some months ago, a downward tendency began and it is possible to
contract for tankers of 10,000 tons and over for between $140 and $150
per ton.

Although the transportation costs are based, in this report, on
steamers rated at 10,000 d.w. tons, the tendency is to increase the ca-
pacity of the boats to 15,000 and 20,000 tons, as shown on Table 9. The
Eagle Oil and Transport, and the Standard Oil of New Jersey have
under construction several 20,000-ton boats.

As a general rule, a boat built for a tanker should carry, in barrels,
on an average six times its deadweight tonnage; for example, a 10,000-ton
tanker should average at least 60,000 bbl. of oil per trip. Naturally, the
exact figures depend, among other factors, on the weight of the oil,
design of tanker, amount of space needed for tanker's fuel (more bunker
space will be needed on longer trips) season of the year, draft of boat as
compared to the depth of water in the loading and unloading harbors,
etc. Five-thousand-ton tankers will carry somewhat over 30,000 bbl.;
7000-ton tankers about 45,000 bbl.; 10,000 d.w. ton tankers from 60,000
to 65,000 bbl.; 15,000-ton tankers about 95,000 bbl.; and 20,000-ton
tankers about 120,000 barrels.

As a general rule, it has been found more advantageous to equip
tankers with steam engines using fuel oil for steam generation; boats

VALENTIN R. GABFIAS 543

equipped with Diesel type engines have not given as reliable service as
the steamers.

Cost of Transportation

Taking as a unit a 10,000 d.w. ton tanker, able to carry 60,000 bbl. of

011 and upward per trip, and costing $200 per deadweight ton, which is
higher than the present average cost, and assuming other equally con-
servative figures, the cost of transporting oil for round trips taking from

12 to 30 days is shown in Fig. 6.

Thus the cost per barrel for transporting oil in a 10,000 d.w. ton
tanker, from Tampico to Texas ports, 12 days round trip will be 42.5c.;
to New Orleans, 15 days, 53c.; to Florida ports, 16 days, 57c.; and to
New York, 25 days, 88 cents.

If the tanker only cost SI 00 per ton, the correction factors in the
lower left-hand corner of Fig. 6 should be used; thus, the New Orleans
trip will cost 39.64c. per bbl. and not 53 cents.

In corroboration of the figures given by the chart for the cost of
transporting oil, the following is quoted from the Journal of Commerce of
July 29, 1920: "In closing the contracts, the United States Shipping
Board has agreed to charter sufficient tank ships for its transportation
at the Government rate of $6.50 per deadweight ton per month."

Allowing an average of 6 bbl. per deadweight and assuming that the
oil is to be transported from Tampico to New Orleans in a 10,000-ton
tanker costing $200 per deadweight, making two round trips per month,
the Shipping Board charter rate would give a transportation cost of
54.2c. per bbl. against the 53c. per bbl. obtained from Fig. 6.

It is the opinion of competent authorities that for round trips taking
from 12 to 30 days, the various charges for the shorter and longer trips
will about balance each other, leaving a fairly uniform ratio for cost of
transporting oil per barrel for the long and short trip.

CONCLUSIONS

1. The United States and Mexico will produce on an aggregate, in
1920, close to 90 per cent, of the total world's output of petroleum.

2. The Mexican production, in 1920, will aggregate over 25 per cent, of
the world's total.

3. About 75 per cent, of the Mexican exports estimated at 108,000,-
000 bbl. in 1920 go to the United States, and this represents about 25
per cent, of the United States production.

4. Of the oil exported to the United States, about 52 per cent, is
shipped to New York and North Atlantic ports; 27.5 per cent, to Texas
ports; the remaining 18.5 per cent, to New Orleans and Florida ports.

5. Although there has been a gradual increase in the exports of fuel

544 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

VALENTIN R. GARFIAS 545

oil, heavy crude, and crude gasoline, the great increase is due almost
entirely to the greater volumes of light crude exported.

6. The average load per tank steamer trip from Mexican harbors has
increased from 28,000 to 48,000 bbl. from January, 1917, to August, 1920.
The average load to North Atlantic and New York harbors is close to
60,000 bbl. (10,000-ton tankers); about 45,000 bbl. to New Orleans
(8000-ton tankers); 30,000 bbl. to Texas, and Florida ports (5000-ton
tankers). Tank steamers under construction, 12,000, 15,000, and 20,000
tons, when placed in operation, should increase the average net carrying
capacity per tanker trip.

7. The transportation costs given in Fig. 6, based on 10,000 d.w.
ton tankers, are very conservative; in fact, appreciably lower figures
are fully justified at present. The figures given apply to boats owned by
the operating company, not to chartered boats.

8. No reliable figures of Mexican oil in storage are available.

MEXICAN TAXATION ON PETROLEUM AND ITS PRODUCTS

Although the following analysis of Mexican taxation on petroleum
was made by the writer when acting as Special Commissioner of the
Petroleum Department of the Mexican Government, the conclusions
drawn represent his own views, for which the Mexican Government can
in no way be held responsible.

The Mexican Government at present levies on petroleum and its
products not utilized in the Republic, the so-called Export Stamp Tax,
which is based on certain percentages, varying with the grades of oil, of
the prices of the exported commodity. These prices may be determined :
(1) as those prevailing within Mexico; (2) prices in New York, or other
American harbors, less marine transportation costs; (3) the prices, any-
where in the United States, of similar petroleums as regards physical
properties.

The amount of the present taxes that depend on oil prices, which in
turn can be interpreted in three ways, has been, and is the source of
misunderstandings between some of the operators and the government
whenever the government and the companies' manner of evaluating the
oils disagree. The aim of the writer is to pave the way for the removal
of these causes for controversies and to suggest changes that will make
for a more definite and clear basis for taxation.

TAXES PRIOR TO MAY, 1917

With the exception of the usual stamp tax on documents, and such
other minor contributions, the oil companies operating in Mexico did not
pay taxes to the government on about 24,800,000 bbl. produced prior to

VOL. LXV. 35.

546 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

1912. In fact, companies like the Aguila, Huasteca, and the Standard
Oil of New Jersey were exempt from the usual import taxes on machinery,
etc. On July 1, 1912, during the administration of President Madero,
an export tax of 20 centavos per metric ton, approximately 1.54 U. S.
cents per barrel of oil exported, was charged : this tax, which was applied
irrespective of the quality of the oil, was in force until November, 1913,
when it was increased to 75 centavos per metric ton, about 5.77 U. S
cents per barrel, during the Huerta administration. This tax, like the
preceding one, was applied to oil exported, irrespective of its quality,
and was reduced on May 1, 1914, to 60 centavos per metric ton, approxi-
mately 4.62 U. S. cents per barrel, during the Carranza administration
and was in force until May 1, 1917, when the present tax, based on a
certain per cent, of the value of the oils was established. The exports
from 1912 to April, 1917, inclusive, aggregating about 111,700,000 bbl.,
were taxed, therefore, approximately $4,355,000, or about 3.9 U. S. cents
per barrel.

TAXES FROM MAY, 1917 TO DATE

It should be understood that the tax, called in this paper the export
stamp tax, applies exclusively to petroleum and its products and is inde-
pendent of any other former or subsequent tax that applies to petroleum
as well as to other exports. Under this heading may be included the
paper redemption tax (infalsificable), bar dues for oil shipped from Tampico,
etc. It is clear, therefore, that when one speaks of Mexican taxation on
oil, one should differentiate between the export stamp tax, to which
the decree of Apr. 13, 1917, applies and which is based on a certain
percentage of the value of the oils, and any other taxes not inherent to
the petroleum industry. The additional taxes that are not properly oil
taxes are small, compared with the export stamp tax.

THE EXPORT STAMP TAX

The decree of Apr. 13, 1917, on which this tax is based, reads in part
as follows:

. . . that it being of very diversified quality, the petroleum produced in the
Republic, and for the same reason of different commercial value, the tax should have
as a basis the value of each product, in order that it be reasonable and equitable;
that a considerable quantity of this liquid is not utilized because the necessary pre-
cautions are not taken in the exploration work and its daily handling, this circum-
stance occasioning frequent losses, not only to the interested companies, but also to
the Government, on account of the taxes that it fails to collect.

In view of the foregoing, I (the President) have enacted the following decree:
Article 1. All crude petroleum of national production, its derivatives and the
gas from the wells, from the moment that it flows from the ground or leaves the
storage deposits, are subject to a special stamp tax under the following terms:

VALENTIN R. GABFIAS 547

(a) Crude and fuel oil 10 per cent, of assigned value.

Refined gasoline 3 per cent, of assigned value.

Crude gasoline 6 per cent, of assigned value.

Refined kerosene 3 per cent, of assigned value.

Lubricating oils ^c. per liter.

Asphalt $1 . 50 per ton.

Gas 5 per cent, ad valorem.

(For up-to-date rates and changes see Table 1.)

(6) The crude petroleum and its derivatives, when wasted in any quantity,
whether for lack of care or not complying with the legal regulations, will pay a tax
double the one corresponding to similar products.

The products derived from the natural gas of the wells, when it is wasted from the
same reasons, will pay 10 per cent, of its commercial value.

Article 2. (Exempts from tax, oil consumed in Mexico.)

Article 3. (Defines "crude oil," "refined oils," etc.)

Article 4. In order to be able to establish the tax, which, in accordance with
fraction (a) of Article 1, corresponds to each one of the products derived from petro-
leum, the Secretary of Hacienda will fix every two months the prices of said articles
at the shipping ports, taking the average of the values reached in the previous month.
The manifestations or bills that the companies present regarding sales of the same
articles, in the interior in Mexico, will serve as a base for making the estimate
referred to.

In case that no operations of sales take place in the interior, the average value
which these products had in New York the previous month, or in the harbors of the
United States, will be taken, deducting the value of transportation of said products,
from the Mexican to the foreign harbors. If there are no available data to make the
previous calculations, an equal price will be assigned to that which similar articles
have, in regard to physical properties, in the United States, fixing on this price the
respective tax.

THE GRADES OF MEXICAN OILS EXPORTED

Although it is difficult to obtain accurate information regarding the
various grades of oils exported from Mexico, enough data has been ob-
tained to show that, at present and for some time past, the bulk of the
exports can be divided into four classes:

Light or southern crude . 9333 sp. gr. (20 Be*.)

Heavy or Panuco crude 0. 9859 sp. gr. (12 Be".)

Fuel oil 0.9589 sp. gr. (16 B<.)

Crude kerosene or tops . 7527 sp. gr. (56 Be".)

The light crude is exported in large quantities and is also partly
refined in topping plants, which produce a low-flash fuel oil and light tops,
or crude gasoline. The heavy crude is not refined, being used exclusively
for fuel purposes in power plants; its low flash point and high viscosity
prevent its extensive use for marine purposes.

MEXICAN TAXES ON VARIOUS GRADES OF OILS

The export stamp taxes from May, 1917, to January, 1921, for the
four main grades of oils, have been computed and listed in Tables 10 and

548 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

VALENTIN R. QABFIAS

549

550 PRODUCTION. TRANSPORTATION & TAXATION OP MEXICAN PETROLEUMS

13, on the basis of U. S. cents per barrel. These tables show that the
lowest tax, 3.90c. per bbl., was levied on heavy crude in 1917, the highest,
72.7 r c. per bbl., or about 1.73c. per gal., being levied on crude gasoline for
several months in 1920.

In a general way the taxes on light crude have gradually increased
from 7.8c., in 1917, to 18.2c., in September, 1920; fuel oil tax has increased
from 5.7 to 13c.; heavy crude from about 4 to lOc. and back to 8.6c.;
and crude gasoline, from 1.2 to 1.7c. a gallon.

The monthly fluctuation in taxes for the four grades of oils are graph-
ically shown in Fig. 7, which illustrates the comparatively few changes
that have occurred from May, 1917, to March, 1920. The percentage
of increase in the taxes on the various grades is shown in Fig. 8, which
illustrates the abnormal increase of the tax on heavy crude, on March,
1920, as well as the lack of uniformity in the fluctuations of all taxes from
March, 1920, to date.

The average export stamp taxes, in U. S. cents per barrel, paid from
1912 to 1917 were: July, 1912, to November, 1913, 1J; November, 1913,
to May, 1914, 5>^; May, 1914, to May, 1917, 4>^; irrespective of the
quality of the oils, while the average from May, 1917, to December,
1920, for the four main grades of products has been: Heavy crude,
5; light crude, 11; fuel oil, 9; crude gasoline, 56c. per bbl., or IJ^c. per
gallon.

Table 11 shows the total taxes on petroleum and its products, which
include, besides the export stamp tax, others not exclusively applicable
to the oil industry. This table shows the infalsificable, or paper re-
demption tax (one paper peso be paid for each metal peso paid in taxes)
figured on the uniform ratio of 10 to 1 for the relative values of the
paper and metal peso, which ratio undoubtedly gives larger figures than
have been actually paid. Bar dues have been calculated on the assump-
tion that all the oil exported paid these bar dues, while, as a matter of fact,
these dues are applicable only to the oil shipped from the harbor of
Tampico.

The total taxes herein listed represent practically all the returns the
Mexican Government obtains from the oil industry, inasmuch as no
income nor excess profit or similar taxes are in operation in Mexico.

THE VALUE OF MEXICAN OIL

The statement has been often made that the export stamp tax, which
by law should represent 10 per cent, of the price of the oil, actually
amounts to 40 per cent., but the absurdity of such statements can be
realized by analyzing the average taxes from 1917 to date. On the
assumption that these taxes represented 40 per cent, of the prices of the
oils, we would have:

VALENTIN R. GABFIAS 551

PBICE IN MEXICO

Heavy crude

40 PEE CENT. TAX
5c

U. S. CENTS
12^ per bbl

Light crude

He.

27K per bbl.

Fuel oil

9c.

22)^ per bbl.

Crude easoline . .

l^c. oer eal.

3K t>er eal.

The computed prices in this case fall far below the market price, as
any one familiar with conditions can certify. This comparison illus-
trates, further, the difficulties encountered in ascertaining whether the tax
in question is, or is not, the exact percentage marked by law of a price
that, according to the law, can be computed in three ways, none of which
is clearly enough defined to eliminate possibilities of misunderstandings.

It has been advanced by representatives of some companies that the
only proper basis for arriving at the true value of Mexican oils, say at
Tampico, will be found in the selling contracts made between companies,
or between an oil company and the U. S. Shipping Board, which stipulate
the price at the Mexican harbor. In support of this contention, con-
tracts are exhibited showing the prices of Mexican oils varying within
wide limits, but as a rule well below what might be considered a fair
market value. It is further stated, by the supporters of this method of
appraising Mexican oils, that account should be taken of long term con-
tracts which net the companies relatively low figures at the present
time.

On the other hand, it should be evident to any one familiar with inter-
companies' oil contracts, that they do not offer the best means of ascertain-
ing the fair market price, as shown by the following examples: Producing
company A sells its oil at Tampico to transportation company B at a
price that will net little or no profit to the producing company. Com-
pany B,in turn, sells the oil in the United States to marketing company C
for a price that will allow the transportation company to operatejts
boats at a fair profit, leaving to the marketing company the big margin of
profits in disposing of the products to consumers in the United States.
It certainly would be unfair to claim, in this case, that the inter-company
contract price between A and B should be taken as the fair price of the
oil at Tampico.

A second case will give another view of this same question. Produc-
ing company A, when in great need of financial assistance, was forced to
sell its production to outside company B on a long-term contract at a
price that is now considerably lower than the market price; it is decidedly
unfair to claim that the contract price in question represents the actual
market conditions for the duration of the contract.

There is also the case of a long-term contract made under profitable
terms in years past, but with poor judgment as to future prices of Mexi-
can oils. It would be unfair to claim that the prices stipulated in these

552 PRODUCTION, TRANSPORTATION <fc TAXATION OP MEXICAN PETROLEUMS

contracts always represent actual market conditions when the net result
is only to shift profits from one company to another.

The U. S. Shipping Board has made contracts, principally for oils
that the Shipping Board could not use without refining, and the price of
the oil transported was one of the many clauses in the contracts. These
contracts often included certain trading agreements for fuel oils that could
be utilized as bunker fuel, the price of, say, the light crude contracted,
refining of the crude, preferential rights for additional transportation
facilities, etc. Here again, the contract price might well not reveal the
actual market price of the crude.

Were the letter and not the spirit of the 1917 law followed a tax on
gasoline of about 2% U. S. cents per gallon would be justified, in place
of the present tax of 1.7 U. S. cents per gallon, if the current Tampico
price of gasoline were taken into account.

Summarizing the foregoing, it may be safely concluded that as long
as the export stamp tax is based on the prices of oils in Mexico, as defined
in the decree of April, 1917, the result will be endless controversies
between the Mexican Government and the operating companies.

RELATION BETWEEN PRICES OF AMERICAN AND MEXICAN OILS

It should be clearly understood that by the following analysis the
writer does not intend to establish, for instance, a direct ratio between
the prices or values of Mid-Continent crude at the well and those of
Mexican petroleum, nor that the composition of Mexican light crude
corresponds to that of Gulf Coast, Mid-Continent, or Californian crudes,
nor that the price of Mexican oil be established by comparison with the
fluctuations in prices of one or all of the American oils mentioned. The
endeavor is: (1) To analyze the fluctuations in price of the bulk of Ameri-
can oils, viz: Mid-Continent, Californian and Gulf Coast, which aggre-
gate about 85 per cent, of the total production of the United States ; (2)
to establish the history of market fluctuations of these oils and such other
closely related products as bituminous coal so that the average would
represent a fairly stable picture of over-all market fluctuations, independ-
ent of the control of any one interest (official or otherwise) and solely
related to the laws of supply and demand; (3), once this bench mark is
established, to ascertain the relation between the Mexican ad valorem
taxes levied from beginning to date and these average prices, not with
the view of deciding what the price of Mexican oils has been, but in an
effort to ascertain what relation has existed between Mexican taxes and
such independent standard on which future taxation could be based thus
eliminating past controversies between the Mexican Government and the
operating companies. The writer wishes, therefore, to emphasize at
this time that what results are given are not offered as the solution of the

VALENTIN R. GARFIAS

553

554 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

question as to what really has been or is the value of Mexican oils in
American harbors, but are only presented as offering a new and impartial
basis for taxing the Mexican oils exported.

As the law of April, 1917, provided that the value of oils in the United
States may be taken into account after proper allowances are made for
the cost of transporting the oil from the Mexican to the American harbors,
realizing the many difficulties encountered in reaching satisfactory results
by using the prices in Mexico as per companies 7 contracts, etc., the
writer compiled detailed information on the fluctuation of oil values in
the United States from 1917 to date; first, to ascertain whether there has
been over-all market conditions uniformly affecting the value of American
oils in the western, southern and central fields, and, second, to ascertain
what relation, if any, exists between the values of the American and
Mexican products.

The average oil prices listed related to the production of the Mid-
Continent, California and Gulf Coast fields and therefore represent over-
all market conditions. Fig. 9 and Table 12 show that there exists an over-
all market condition uniformly regulating fluctuations in prices of fuels.
As about 50 per cent, of the Mexican exports are delivered to the Atlantic
seaboard, it was thought advisable to include in the analysis the export
price of bituminous coal, with which Mexican oil comes directly, or
indirectly, in competition, the ratio of 1 ton of coal to 3J^ bbl. of oil,
which is the generally accepted equivalent, being decided upon, and the
export price of coal being converted to the barrel-of-oil basis. The
fluctuations of prices of bituminous coal, as shown in Fig. 9, are more
uniform than the oil prices, and more closely follow the average market
conditions.

The Mexican exports to the United States, which are 75 per cent, of
the total exports, equal about 25 per cent, of the American oil production,
so when it is sold on the Atlantic or Gulf Coast seaboards, it has to compete
with the United States petroleums; therefore, the price of the Mexican
oil is controlled by that of the home product. Fig. 9 shows that from
the end of 1919 to date, there has been a sharp increase in the prices of
fuels, both liquid and solid, throughout the United States, and it is in-
conceivable that the prices of Mexican oils, the bulk of which is marketed
in the United States, did not follow these over-all market fluctuations of
values.

RELATIVE COST OF OPERATING IN MEXICAN AND AMERICAN

OIL FIELDS

The claim is often made by some operators that the Mexican oil
taxes should be reduced because of the high cost of development com-
pared with this cost in the United States. But it has been proved that

VALENTIN B. GABFIAS 555

the aver-all costs are lower in the Mexican than in the American fields,
for the average depth of wells in the Mexican fields is less than 2500 ft.,
which is no greater than that in most American fields, and while the cost
of drilling is somewhat greater, it is certainly not much in excess of
drilling wells of the same depth in American fields where conditions are
similar.

In some American fields, the production cost, made up mostly of the
cost of bringing the oil from the underground reservoirs to the surface,
is about 40c. per bbl., and as the life of the well decreases, the production
cost materially increases. On the other hand, the production cost in
Mexican fields is exceedingly low, because practically all the wells are
gushers that flow marketable oil, necessitating no dehydration. The
cost of pipe lines in the Mexican fields is not materially greater than in
some United States fields; the Mexican pipe lines, as a rule, are a good
deal shorter than the average lines from the American oil fields to
sea-board.

But the main reason for the lower operating cost in the Mexican fields
can be found in Table 1. In order to produce, in round figures, 100,000,000
bbl. per year, it is necessary in California to pump about 9400 wells, while
in Mexico 250 wells produce a greater amount by natural flow. In
fact, the number of wells actually producing in Mexico is much nearer
100 than 250. The California well averages about 29 J^ bbl. per day,
while the productivity of the Mexican wells ranges (according to whether
we class as producers every well capable of producing or only those
actually producing) between 1190 bbl. and 3000 bbl. per day. Cali-
fornia conditions are well above the average in the United States, as the
228,000 wells producing in the country only average about 5J^ bbl. per
well per day, as compared with 29^ bbl. for the California wells. Besides
these producing wells, in the United States and Mexico, many dry holes
have been drilled; about 6000 wells have been abandoned each year from
1913 to 1917 inclusive in the United States while the total number of
wells abandoned in Mexico to date is less than 600.

These statistics prove the low cost, everything considered, of operat-
ing in the Mexican oil fields; a closer analysis discloses the fact that in no
other oil field have such economical conditions for operations prevailed
as in the Mexican fields to date.

RELATION BETWEEN AVERAGE OIL-COAL PRICE AND MEXICAN

TAXES

The average prices of American petroleums and bituminous coal,
which represents market conditions of these commodities in the United
States, are given in Tables 12 and 13 and are graphically shown in Figs.
7 and 10. These records show a gradual increase in the average price,

556 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

VALENTIN R. GARFIAS 557

from $1.10 per bbl. in January, 1917, to $1.60 per bbl. in Decem-
ber, 1919, followed by an increase during 1920, from $1.60 to $2.77.
The average price increased, therefore, 45.5 per cent, during the years of
1917 to 1919 inclusive, and 73 per cent, in the first eleven months of 1920;
the over-all fluctuations from January, 1917, to November, 1920, repre-
sent close to 15.2 per cent.

Table 13 shows the per cent, relations, by months, between the average
oil-coal price and the export stamp tax on the four grades of oils exported;
the figures indicating that the average tax on light crude corresponds
approximately to 7 per cent, of the type price (see Fig. 10), the percentage
during August, 1920, of 5.98 being about the lowest recorded; the tax on
fuel oil represents on an average, 5.4 per cent, of the oil-coal price, the
tax for August, 1920 being in proportion the lowest so far levied.

This analysis, based on facts, clearly shows that the Mexican export
stamp taxes, with the possible exception of that on heavy crude, are
lower in relation to the average market conditions, at the present time,
than when initiated in May, 1917.

TAX CONTROVERSIES BETWEEN MEXICAN GOVERNMENT AND OIL

COMPANIES

Although a number of important foreign companies have always worke^
in harmony with the Mexican Government, as was stated to the writer by
their representatives in the course of this investigation, other companies
have questioned any increase in taxation with the resulting controversies
between these companies and the government whenever such changes
occurred.

It is undoubtedly true that the principle on which the present Mexi-
can tax operates has not been successful, nor has it met in its application
with the full approval of most of the operating companies. This is due
not so much to the amount of taxes actually paid as to the inability of
the operators to foretell when or what increases will take place, thus
preventing sellers and purchasers from taking proper care of these changes
at the time of fixing contract prices that extend for considerable time.
This has raised difficulties between buyer and seller, the former in some
cases being willing only to agree to pay the prevailing tax when the con-
tract is made, thus leaving the seller unable to collect any additional
amount in case the tax is increased before the expiration of the contract.

It appears, therefore, that although the operators are not justified in
asking for a reduction of the present tax, in order to safeguard the inter-
ests of bona fide marketers the Mexican tax should be revamped to
conform with the usual business transactions between buyer and
seller.

558 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

eo
<

Cij

I -s

3 .2

S5?

OOOi-iOOOOOri

111

1 3

g s

3~>.

02 oSJO

ro' \

S.6

.... 2 .

ooeotOtH d o

S OS t>.

oo'o'd

e
e
oil
de gasoline

OO>-iOO O

0000<-iOOOOOO

_ _ _ t^

OS 05 OS OS

o' o o o'

r-lr^,-!^

05 0500

COOJOSt-

VALENTIN R. GARFIAS

559

IOIOOO

C3 Ot>-O
C^COOOCO

os-^co'co

eococ5O
>o

coo>ooo

CO CO N <3>

iiii

O^Vg

8S 88

iLiS

g ||

>o -*t-

ooot^

COOC3OJ

ooo

CO"5O5CO

OOO

t 1-1

Tf< CtCN

HrHOrt 00

T-IOOOO

^H^lOrH 00

i-tOOOO

T-trHOrH 00

^OOC

-HrHO^H 00

-000.

OOOOCOCOCO

OOOCO

OOOOCOCOCO

OOOCO

OOOOCOCOCO

OOOCO

OOOOCOCOCO

OOOCO

OOOOIN^CO
OOOO--i'-"O

SoSS

oooocsSco

So^S

88Sg 5 S

Is 5

oooolSco

OCO 100000

CNU5CSO

OCOiOOOOO

oco>ooooo

1-HiH l-H

CO>OO>O

OCO>OOOOO

eooojO

S2S

OCX CO CO
CMi-li-liQ

OMCOCO

<N>H^HIO

OC4COCO

laws!

CO 00 1C iO

o'o'od

CO>OOOCNI

cooooo
dodo

COOJOJt-
C350JOSt>.

do o'd

o'do'd

gcodcooo'S

li-iiii

O 05 05 05

COOO>OIO

sss

CO CO IOO
OSOJCSt-

ssss

COO>CC

COiOO

05 05 03 t>

coojcso

C^^t^^H
CO 00 >0 10

0505O5t-

0000

: : ' ' - "g

0000

: : : : : :

1 '8

:j iS

::::::

; ;

::::::

" " *

feOOOPJOM

Crude
Crude
Fuel oil
Crude gasolii

ill

Crude
Crude
Fuel oil
Crude gasolii

ill!

571 "

03 0)

O O 03*5 g 0) no

Crude
Crude
Fuel oil
Crude gasolir

560 PRODUCTION, TRANSPORTATION A TAXATION OP MEXICAN PETROLEUMS

1 I

- 3

> *s

o >

I?:

: "*

14!

K .

*!?

* Ins

ooe

2-3

o'o'dd

C C C C M ~ C

CQiOOCO OOO

S22S

oooo

line

e g

VALENTIN R. GARFIAS

561

^~~ S

= - = i=

oosoeeec

r ~ - - -

oooo

cscscsr
do do

111

OUfe

244^1

Puflo

' iruda
i-i'lfl
...
Uofined Raiolin*
' ' <i'lo gsHolinn
Keroiene, orude or refined

Crude.
Fuel oil...,

Fuel oil
Crude
Crude.
Gftoll
Unfilled KiiM
Crude aiol
Keroiene, o

<!rude
Fuel oil

562 PRODUCTION, TRANSPORTATION A TAXATION OF MEXICAN PETROLEUMS

.2* *

CQ
P

llli

KJiQiQO

T-H -^* C> O

IOOl " l S

OSP

iH IO

-2

a.a

isi

^d.

c
o a

c ^

oocooo

000<0

OOOOOCO00

000<0

s| C

OQ-

exican
Iuation

is
fj

o>oo

1815

s-y

W 2

oeoooo
t-i

IOCO<NO

CDCO^HCOCOOOO

S22

OOJCOCO

O (NOD CD

M rt

GQ
p

1-1
fe'

CO OS OS t^
CO C COIN
CO 00 1C

ssss

OS OS 03 l>

ddo'd

dodo

COOSCJOS

c3 ]

fH r-H

b* !" '

COOO'OO

rHf^ H CD rH

CO 00 1C IO

C '^J t.

OS OS

OS OS OS t

03 OS 03 OS 03

Oi Oi Oi t^

1
i

I i

0000

00000

0000

Hiilllj

1
c

Fuel oil
Crude

Crude
Gas oil
Refined gasoline

Kerosene, crude or re

Crude
Crude
Fuel oil

Fuel oil
Fuel oil, heavier thai
Crude
Crude
Gas oil
Refined gasoline
Crude gasoline
Kerosene, crude or re

Crude
Crude
Fuel oil
Crude gasoline

VALENTIN R. GARFIAS

563

OOOOM

00000eo0>

oooooco<o<o

OOOOOCOOCO

CO CO i-l CO <O O O O

CO OS
COiO

eocio>o

OS OS OS t^

ooo'o'

OJOSt-

oooo

iHbi^CO<-l

OSOSO>0>0

o'o'ddd

i-i K ,-t ;o .-i

OOOOOS

oooo

CO OS OS OS
(NrJtt^rH
COOOOO
OSOOSt>.

oooo

O> OS OS OS OS

odddd

CO OS OS OS

(M^^,-!

CO 00 10 10
OS OS OS N-

e
l oil
de gas

I
ii

3-3"

gasoline
asoline.
ne, crude

as
fin

il
gasol

'S 3 3 Wt

Crude
Fuel o

564 PRODUCTION, TRANSPORTATION & TAXATION OF MEXICAN PETROLEUMS

CONCLUSIONS AND RECOMMENDATIONS

The foregoing discussion clearly indicates: (1) That the rate of
Mexican taxation on oil exported and, in fact, the aggregate of all
Mexican taxes affecting the oil industry, far from being burdensome in
nature as some operators contend, have been and are, if anything,
reasonably low. (2) Mexican oils exported prior to May, 1917, were
taxed only about 4 U. S. cents per barrel, and in several cases the ex-
porting companies were and are exempt from paying the customary
import duties on machinery and other supplies thus further benefiting
from their Mexican operations. (3) That the export stamp taxes levied
under the decree of April, 1917, are in proportion, lower in August, 1920,
than in April, 1917, when the law was put into effect. (4) That the
basing of the tax on the price of Mexican oils in Mexico, as the decree
provides, has given rise to endless arguments and dissensions. (5) That
the tax as applied creates difficulties between the seller and purchaser of
Mexican oils, which can and should be eliminated. (6) That it would be
advantageous to apply Mexican standards for measuring oils, within
the metric system, on the volume basis, rather than on the weight basis,
inasmuch as all Mexican oil is sold by volume.

Keeping clearly in mind the rights of the Mexican Government as
well as the just claims of the operators, and realizing that many of the
difficulties can be overcome by the establishment of some stable "bench-
mark" directly related to market conditions, on which to base the value of
Mexican oils and therefore the taxes on their products, the writer offers
the following recommendations:

1. That the Mexican tax on each grade of exported oils be based on
percentages of the average American oil-coal price, as defined in this
report. ' .;.;

2. That these percentage relations between the tax on any one grade
of oil and the oil-coal price should remain practically constant unless new
conditions should develop to make a change imperative.

3. That, if possible, monthly variations of the average oil-coal price
be taken into account.

4. That the tax be applied on the volume (cubic meter) rather than
on the weight (metric ton) of the oil exported (the average oil-coal price
in dollars per barrel converted to pesos per cubic meter is shown on
Table 12).

5. That the law of April, 1917, be abrogated and a new law enacted
covering, in a general way, the main points herein advanced.

VALENTIN R. GARFIAS

565

TABLE 11. Total Mexican Export Taxes in U. S. Cents Per Barrel of

42 U. S. Gal

and Month

Export

Stamp

Tax

Infalsificable =

10 Per Cent, of

Export Stamp Tax

Bar Dues - 10

Centavoa per

Metric Ton

Light Crude
20 Be*.

May, 1917 7.813 0.781

September, 1917 9.294 0.929

November, 1917 j 9.665 0.966

July, 1918 j 11.145 1.114

July, 1919 10.775 1.077

November, 1919 11.145 1.114

March, 1920 15.713 1.571

July, 1920 16.698 1.669

September, 1920 18.179 1.817

December, 1920 i 18.179 1.817

Fuel Oil '
16 Be*.

May, 1917 5.737 0.573

September, 1917 6.878 0.687

November, 1917 7.258 0.725

July, 1918 9.160 0.916

March, 1920 11.913 1.191

July, 1920 12.201 1.220

September, 1920 j 12.962 1.296

December, 1920 1 12.962 1 .296

Heavy Crude
12 Be*.

May, 1917 3 . 910 . 391

September, 1917 4.301 0.430

July, 1918 4.692 0.469

March, 1920 10. 167 1 .016

September, 1920 8.603 0.860

December, 1920 8.603 0.860

Crude Gasoline
56 Be*.

May, 1917 52.412 5.241

September, 1917 53.604 5.360

January, 1918 55.986 5.598

March, 1920 67.899 6.789

May, 1920 72.663 7.266

September, 1920 67.899 6.789

December, 1920 67.899 6.789

0.740
0.740
0.740
0.740
0.740
0.740
0.740
0.740
0.740
0.740

0.760
0.760
0.760
0.760
0.760
0.760
0.760
0.760

0.782
0.782
0.782
0.782
0.782
0.782

0.597
0.597
0.597
0.597
0.597
0.597
0.597

566 PRODUCTION, TRANSPORTATION <fc TAXATION OF MEXICAN PETROLEUMS

TABLE 12. Relation Between American Fuel Prices and Mexican Export
Stamp Taxes on Petroleum and its Products

NOTE. One Cubic Meter = 6.2899 bbl. One U. S. dollar = Two Mexican pesos

Month and Year

Dollars per Barrel

Pesos per Cubic Meter

Mid-
Conti-
nent
Crude

Calif-
ornia
Crude

Bitumin-
ous Coal
Export
Price
(3.5 bbl.
per ton)

Gulf
Coast
Crude

Average
Price

?Se 6

Present Stamp Tar

20
Be.
0.9323

12
Be.
0.9849

56
Be.
0.7519

16
Be.
0.9579

1917
May

1.70
1.70
1.70
1.85
2.00
2.00
2.00
2.00

2.00
2.00
2.25
2.25
2.25
2.25
2.25
2.25
2.25
2.25
2.25
2.25

2.25
2.25
2.25
2.25
2.25
2.25
2.25
2.25
2.25
2.25
2.33
2.50

2.97
3.00
3.50
3.50
3.50
3.50
3.50
3.50
3.50
3.50
3.50
3.50

0.82
0.92
1.02
.02
.02
.02
.02
.02

.02
.02
.02
.02
.27
.27
.29
.29
.29
.29
.29
.29

.29
.29
.29
.29
.29
.29
.29
.29
.29
.29
.29
.29

.29
.33
.33
.58
.58
.58
.70
.70
.70
.70
.70
.70

0.991
.011
.091
.140
.100
.120
.360
.017

.086
.165
.147
.136
.046
.105
.142
.122
.148
.185
.142
.194

.336
.250
.428
.371
.200
.250
.228
.320
.400
.438
.465
.380

.600
.560
.615
.815
2.028
2.280
2.660
2.957
2.957
3.050
2.870
2.415

.00
.00
.00
.00
.00
.00
.00
.00

.00
.00
.35
.35
.35
.35
.35
.35
.80
.80
.80
.80

.50
.25
.25
.00
.00
.00
.00
.00
.00
.00
.00
.25

1.75
2.00
2.50
3.00
3.00
3.00
3.00
3.00
3.00
3.00
3.00
2.50

.128
.158
.203
.253
.280
.285
.345
.259

.277
.296
.442
.439
.479
.494
.508
.503
.622
.631
.621
.634

1.594
1.510
1.555
.478
.435
.448
.442
.465
.485
.495
.521
.605

1.903
1.973
2.236
2.349
2.527
2.590
2.715
2.789
2.789
2.812
2.77
2.529

14.190
14.567
15.133
15.762
16.102
16.165
16.920
15.838

16.064
16.303
18.140
18.102
18.606
18.794
18.970
18.907
20.404
20.518
20.392
20.555

20.052
18.995
19.562
18.593
18.052
18.216
18.140
i 18. 429
18.681
18.807
19.134
20.191

23.939
24.820
28.128
29.550
31.789
32.582
34.154
35.085
35.085
35.375
34.846
31.814

0.983
0.983
0.983
0.983
.169
.169
.216
.216

.216
.216
.216
.216
.216
.216
.402
1.402
1.402
1.402
1.402
1.402

.402
.402
.402
.402
.402
.402
.355
.355
.355
.355
.402
.402

.402
.402
.977
.977
.977
.977
2.101
2.101
2.287
2.287
2.287
2.287

0.492
0.492
0.492
0.492
0.541
0.541
0.541
0.541

0.541
0.541
0.541
0.541
0.541
0.541
0.590
0.590
0.590
0.590
0.590
0.590

0.590
0.590
0.590
0.590
0.590
0.590
0.590
0.590
0.590
0.590
0.590
0.590

0.590
0.590
.279
.279
.279
.279
.279
.279
.082
.082
.082
.082

6.593
6.593
6.593
6.593
6.743
6.743
6.743
6.743

7.043
7.043
7.043
7.043
7.043
7.043
7.043
7.043
7.043
7.043
7.043
7.043

7.043
7.043
8.542
8.542
9.141
9.141
9.141
9.141
8.542
8.542
8.542
8.542

0.722
0.722
0.722
0.722
0.865
0.865
0.913
0.913

0.913
0.913
0.913
0.913
0.913
0.913
.152
.152
.152
.152
.152
.152

.152
.152
.152
.152
.152
.152
.152
.152
.152
1.152
1.152
1.152

.152

.152
.499
.499
.499
.499
.535
.535
.631
.631
.631
.631

June

July . .

August ....

September

October

November

December

1918
January . .

February ... .

March

April

May

July

August

September

October. . . ....

November

December . . .

1919
January

February

March

April

May

June

July

August

September

October

November

December
1920
January

February

March

April

May

June

July

August . .

September . . .

October

December

VALENTIN E. GARFIAS

567

TABLE 13. Mexican Export Stamp Tax Showing Percentage Relation to
Average Oil and Coal Price from May, 1917 (in U. S. cents per Barrel)

Year and Month

Average
Oil and
Coal
Price

Light Crude
20 Be.
(0.9323)

Fuel Oil
16 Be
(0.9579)

Heavy Crude
12 B6.
(0.9849)

Crude Gasoline
56 Be.
(0.7519)

Tax

Per

Cent.

Tax

Per

Cent.

Tax

Per

Cent.

Tax

Per
Cent.

1917
May

$1.128
1.158
1.203
.253
.280
.285
.345
.259

.277
.296
.442
.439
.479
.494
.508
.503
.622
.631
1.621
1.634

1.594
1.510
1.555
1.478
.435
.44S
.442
.465
.485
.495
.521
.605

.903
.973
2.236
2.349
2.527
2.590
2.715
2.790
2.790
2.812
2.77
2.529

$0.078
0.078
0.078
0.078
0.093
0.093
0.097
0.097

0.097
0.097
0.097
0.097
0.097
0.097
0.112
0.112
0.112
0.112
0.112
0.112

0.112
0.112
0.112
0.112
0.112
0.112
0.108
0.108
0.108
0.108
0.112
0.112

0.112
0.112
0.157
0.157
0.157
0.157
0.167
0.167
0.182
0.182
0.182
0.182

6.92
6.73
6.50
6.24
7.26
7.23
7.19
7.68

7.56
7.46
6.70
6.72
6.53
6.47
7.39
7.42
6.87
6.83
6.88
6.82

6.99
7.38
7.17
7.54
7.77
7.70
7.47
7.36
7.26
7.21
6.94
6.94

5.86
5.65
7.03
6.69
6.22
6.06
6.15
5.98
6.53
6.47
6.57
7.2

$0.057
0.057
0.057
0.057
0.069
0.069
0.073
0.073

0.073
0.073
0.073
0.073
0.073
0.073
0.092
0.092
0.092
0.092
0.092
0.092

0.092
0.092
0.092
0.092
0.092
0.092
0.092
0.092
0.092
0.092
0.092
0.092

0.092
0.092
0.119
0.119
0.119
0.119
0.122
0.122
0.130
0.130
0.130
0.130

5.08
4.95
4.77
4.58
5.37
5.35
5.40
5.77

5.68
5.60
5.03
5.04
6.53
4.86
6.07
6.09
5.64
5.62
5.65
5.61

5.75
6.07
5.89
6.20
6.39
6.33
6.35
6.25
6.17
6.13
6.02
5.70

.4.81
4.64
5.33
5.07
4.72
4.60
4.50
4.38
4.66
4.63
4.70
5.14

$0.039
0.039
0.039
0.039
0.043
0.043
0.043
0.043

0.043
0.043
0.043
0.0 4 3
0.043
0.043
0.047
0.047
0.047
0.047
0.047
0.047

0.047
0.047
0.047
0.047
0.047
0.047
0.047
0.047
0.047
0.047
0.047
0.047

0.047
0.047
0.102
0.102
0.102
0.102
0.102
0.102
0.086
0.086
0.86
0.86

3.46
3.38
3.25
3.12
3.36
3.35
3.20
3.42

3.36
3.32
2.97
2.99
2.91
2.88
3.11
3.12
2.89
2.88
2.88
2.87

2.94
3.11
3.02
3.18
3.27
3.24
3.25
3.20
3.16
3.14
3.09
2.92

2.47
2.38
4.55
4.33
4.02
3.92
3.74
3.64
3.08
3.06
3.10
3.40

$0.524
0.524
0.524
0.524
0.536
0.536
0.536
0.536

0.560
0.560
0.560
0.560
0.560
0.560
0.550
0.560
0.560
0.560
0.560
0.560

0.560
0.560
0.560
0.560
0.560
0.560
0.560
0.560
0.560
0.560
0.560
0.660

0.560
0.560
0.679
0.679
0.727
0.727
0.727
0.727
0.679
0.679
0.679
0.679

46.45
45.26
43.57
41.82
41.88
41.71
39.85
42.58

43.84
42.53
38.82
38.91
37.85
37.47
37.13
37.25
34.52
34.32
34.54
34.26

35.12
37.08
36.00
37.87
39.01
38.66
38.76
38.22
37.70
37.44
36.80
34.88

29.42
28.36
30.36
28.90
28.74
28.06
26.76
26.04
24.35
24.30
24.50
26.85

June .... ...

July

August . . ....

September

October

November . . .

December

1918
January

February

March

April

May

June

July

August

September ....

October

November

December

1919
January

February

March

April

May

June

July. .

August

September

October

November

December

1920
January , . . .

February

March

April

May

June

July

August

September >.

October

November
December ....

568 EFFICIENCY IN USE OF OIL AS FUEL

Efficiency in Use of Oil as Fuel

BY W. N. BEST, D. So., NEW YORK, N. Y.

(St. Louis Meeting, September, 1920)

THIS paper is not intended as a scientific discussion of the combustion
of oil but is written from the standpoint of an operator who has the
experience and qualifications necessary to guide others in producing
the most economical results in the use of liquid fuels. Oil, in this paper,
usually means petroleum or its products but incidental reference is made
to other liquid and gaseous fuels, so that the term may be considered
as referring to all liquid and gaseous hydrocarbons in comparison with
solid fuels, as coal and wood. However, only a few of the principal
factors in the use of oil as a fuel can be given.

The present, and prospective, high price of coal is causing users of
fuel to renew inquiry as to the merits of other forms of fuel for industrial
purposes. Crude oil (petroleum) is proving to be one of the world's
most valuable mineral resources. The recent discovery that oil underlies
a considerable area of the United States, Mexico, and other parts of the
world to a greater extent than was formerly believed and the large
production of some of the wells in these areas shows the probable quantity
of fuel oil that may now be available. Through the energy of Lord
Cowdrey, who was one of the pioneers of the oil industry in Mexico, oil
has been discovered in England; some prominent geologists believe that it
may be found in quantity in Great Britain.

For years, oil has been known to be of great value in the manufacture
of metals. It has proved incomparable in forge shops, steel foundries,
heat-treating furnaces, and wherever accuracy of temperatures is essen-
tial, or where a maximum output is desired as well as quality of metal.
In some types of equipment, the output produced with oil as fuel is
double that obtained with coal and at a reduction of 50 per cent, in the
cost of the fuel. For example, in drop-forging plants, the metal is always
waiting for the man when oil is used as fuel, whereas with, coal, the man
must wait for the metal to become sufficiently heated.

It has only been since January, 1919, that the oil supply could be relied
on for boiler service, owing to the war conditions and the inability to get
oil tankers for the delivery of the oil from Mexico to Atlantic ports;
but now a constant supply is assured, and many manufacturers are
installing it in their power plants. The cost varies with the size of the

W. N. BEST 569

plant. In New England and along the Atlantic coast, where the boiler
horsepower is large, this fuel is very attractive, for one man can fire and
water-tend twelve 300-hp. boilers. It raises the general condition of the
man firing the boilers, because the burning of oil is an art and necessitates
brain rather than brawn. This fuel responds immediately to the will of
the operator in meeting peak or fluctuating loads. The fire room is clean
and sanitary, dust from coal and ashes being eliminated. There is prac-
tically no loss in fuel, as only a small part of the oil in the storage tank is
heated, and that just enough for it to be pumped readily from the storage
tank to the supply tank. The handling of the fuel is inexpensive; and it is
speedily delivered from the oil tank or tanker. There are, however,
certain fundamental principles that must always be observed in making
crude-oil installations.

TEMPERATURE OF FUEL

The temperature of the fuel and the method of supply are especially
vital points. Oil below 20 Be* should be heated to just below its vaporiz-
ing point; steam should always be used for this purpose, as it gives a very
accurate temperature; the supply is usually obtained from the exhaust of
the pump. Numerous efforts have been made to heat the oil, while
passing through the pipes, by electric currents and by heat from coke,
gas, and oil fires; these methods have always proved inferior to steam.

Thermometers should always be used, for the manufacturer who heats
his fuel accurately and uniformly every day is the one who obtains the
greatest efficiency from the fuel burned.

SUPPLY LINES

Supply lines should be so laid as to insure the constant circulation of
fuel through all the oil-supply pipes from the pump to the burners. A
pressure relief valve should always be placed at the farther end of the
burner installation, and the overflow pipe should always return the un-
used fuel to the supply tank. This is imperative especially when using
heavy oils, as they must be heated to reduce their viscosity. Many
people have put in a large oil main and run laterals from the main to the
boilers or furnaces. Then when a boiler must be washed out or a furnace
is shut down for repairs, the oil solidifies in the oil pipe or, if it does not
solidify, the residuum from the oil collects in these pipes, causing annoy-
ance and unnecessary trouble. The locating of the oil-storage tank and
the laying out of the pipe lines are engineering feats, just as much as the
equipment of the boilers or furnaces.

The oil pumps should be brass lined. Two should always be provided,
one being held in reserve for use in cases of any emergency. Air chambers

570 EFFICIENCY IN USE OF OIL AS FUEL

and pressure gages should be used; the former to reduce the pulsations
caused by the displacement of the oil by the piston and the latter to
record the oil pressure maintained upon the oil-supply line. The spring
of the pressure-relief valve should be very sensitive, in order that it may
release quickly without causing a variation of more than Y Ib. (0.14 kg.)
pressure on the oil supply to the burners. Oil meters should be used
whenever possible; the foreman of a boiler plant or furnace department
provided with these instruments is encouraged to see that the strictest
economy in fuel is maintained.

TYPES OF BURNERS AND THEIR USE

Numerous oil burners are on the market but the three types most
common are: The external atomizing type, which is largely used in loco-
motive and stationary boilers and in large furnaces; the internal atomizing
type, which is chiefly used on small furnaces; and the mechanical type of
burner used on ocean-going vessels, which forces the oil at high pressure
through a small aperture, thus making a funnel-shaped flame. This
type of burner is used on ocean vessels because no steam is required for
atomizing, consequently there is no loss of water. This saving in water,
however, is accompanied by loss in fuel, for more oil is required to
replace a ton of coal while using a mechanical burner than with the exter-
nal atomizing burner, because a mechanical burner cannot atomize the
fuel. For example, 180 gal. (681 1.) of oil is the equivalent of a long
ton of coal (calorific value, 14,000 B.t.u. per Ib.) when using a mechanical
burner; while with the use of an atomizing burner only 147 gal. of oil is
the equivalent.

When purchasing atomizing burners, several points should always be
considered.

1. The burner must not carbonize. A burner that carbonizes should
be scrapped at once, as it is not dependable, is wasteful of oil, and requires
a great deal of care and attention. Such a burner reduces the burning
of oil from a science to a continuous hazard and care.

2. The oil and steam orifices should be independent of each other so
that excessive oil pressure is not required and so that no cutting effect
is produced when burning oil containing residuum or sand.

3. The burner should be so constructed and filed that it will pro-
duce a flame of sufficient length and width to fill the combustion chamber
of the furnace or firebox of boiler; in fact, just as perfectly as a drawer
fits into its opening in a desk.

4. The oil orifice should be large enough to permit free exit of heavy
oils and tars therefrom, and the atomizer opening should be as small as
possible in order to reduce to a minimum the amount of steam or com-
pressed air used for the atomization of the fuel.

W. N. BEST 571

For boiler equipments, steam is preferable as an atomizing agent if
20 Ib. (9 kg.) pressure or more is carried upon the boiler; but for smaller
pressures air should be used. For furnace equipments, air is preferable
to steam for atomizing purposes as it reduces to a minimum the amount of
moisture in the furnace.

Today boiler settings are demanded that give ample room for com-
bustion. Boilers for 300 degrees overload are being set with a distance of
14 ft. (4.3 m.) from the coal stokers to the elements of the boiler. When
burning oil, the larger the combustion chamber (up to a certain limit),
the greater is the efficiency obtained from the fuel and the higher is the
boiler horsepower rating obtained. Recording C0 2 instruments should
be used in order to gage the air supply accurately and prevent loss of fuel
through excessive air supply. For furnace equipments, pyrometers are
essential.

Mexican oil is high in sulfur, often containing as much as 3.8 per cent.
It is therefore necessary that a combustion chamber be used on furnaces
so that the atomized oil may be consumed before it reaches the furnace
proper. In boilers there is no difficulty because of sulfur, no matter of
what material the stock is made. The question is often asked, "Do steel
stacks deteriorate from the use of oil containing as high a percentage of
sulfur as Mexican oil?" There will be no deterioration unless the stack
temperature reaches 850 F. In ordinary boiler practice, there is, there-
fore, no likelihood of any detrimental effect because the stack temperatures
do not reach so high a degree. Many people condemn the use of this
fuel in furnaces because their furnaces do not have combustion chambers
to consume the sulfur; when this is consumed in the furnace, there is a
detrimental effect upon the metal and the odor in the shop causes the men
to complain. In open-hearth furnace work, it has been found good prac-
tice to use the lighter oils until the charge is brought down and is covered
with slag, after which the Mexican oil can be used with no detrimental
effect upon the metal.

COST OF OPEKATING WITH OIL AND COAL

Many engineers and manufacturers take the calorific value of the oil
and the calorific value of the coal as bases from which to estimate the
difference in cost of operating with these two fuels. This should not be
done as the figures thereby obtained are incorrect.

In flue-welding furnaces, 58 gal. of oil is the equivalent of a long ton
of coal (2240 Ib.) due to the fact that in welding with coal, for safe-
ending the flue, it is necessary to coke the fire; this not only means a loss
of time but also a loss of the volatile hydrogen and hydrocarbon gases,
much of the calorific value of the fuel. These gases are utilized in boiler
practice; here the economy effected depends largely on the size of the

572 EFFICIENCY IN USE OF OIL AS FUEL

plant, for one man can fire and water-tend a battery of twelve oil-fired
boilers almost as easily as he can care for one boiler. With proper
equipment, the tonnage of a locomotive is increased 15 per cent, when
changed from coal to oil.

The equivalent of one long ton of coal, in the average locomotive
service, is 180 gal. oil; in the average stationary boiler practice,
147 gal.; in forging furnaces, 80 gal; in heat-treating furnaces, with low
temperatures, 80 gal.; and in heat-treating furnaces with high tempera-
tures and annealing furnaces, 63 gal. In working these figures, it must
be noted that, in each instance quoted, the oil has a calorific value of
19,000 B.t.u. per Ib. and weighs 7J^ Ib. per gal. while the coal averages
14,200 B.t.u. per Ib. and weighs 2240 Ib. per ton.

3H bbl. oil (42 gal. per bbl.) is the equivalent of 5000 Ib. hickory or
4550 Ib. white oak.

6 gal. oil equals 1000 cu. ft. of natural gas of calorific value of 1000
B.t.u. per cu. ft.

3M gal- oil equals 1000 cu. ft. of commercial or water gas of calorific
value of 620 B.t.u. per cu. ft.

2J4 gal. oil equals 1000 cu. ft. byproduct coke-oven gas at 440 B.t.u.
per cu. ft.

0.4? gal. oil equals 1000 cu. ft. blast-furnace gas at 90 B.t.u. per cu. ft.

Steel works are now utilizing their blast-furnace gases, which are of
low calorific value, being on an average but 90 B.t.u. per cu. ft. For this
reason, it is customary, when these gases are used in boilers, large furnaces,
etc., to use an auxiliary fuel in combination therewith. This auxiliary
fuel is usually coal tar (the byproduct of coke ovens); this makes a
fine combination. Usually 10 gal. of coal tar are made from every ton
of coal coked in byproduct coke ovens; this tar has a calorific value of
162,000 B.t.u. per gal. When this coal tar is not available, crude oil
is used.

Efforts have been made in West Virginia lately to retain within its
border all the natural gas produced in that state. If those fostering
this movement succeed, within a period of two years there will be scarcely
any natural gas used in the states of Indiana, Ohio, and Pennsylvania.
The small quantity of natural gas produced in these three states will be
used for domestic or household purposes, rather than in furnaces, etc.
Oil, therefore*, is the fuel that will be used as it is particularly adapted for
furnaces in which natural gas was originally used.

DISCUSSION

S. 0. ANDROS,* Chicago, 111. The most important thing in the burn-
ing of fuel oil is the design of the furnace. Almost any of the good
burners on the market will be efficient, if the furnace is properly designed.

* Editor, OH News.

DISCUSSION 573

Without proper furnace design, it is impossible to get efficient operation
of the burner. The burner itself is not so much of an item in the domestic
field as the assembling of the system for domestic use.

RALPH R. MATTHEWS,* Wood River, 111. In 1911, when connected
with the Bureau of Mines, I inspected various installations of fuel oil
burners in Seattle, Portland, and San Francisco and found that every
engineer had his pet type. The results seemed to show that as long as
the oil is atomized properly, the manner in which it is atomized is not of
great importance, but that the furnace must be properly designed.
When the furnace design is not proper, there is overheating and probably
excessive stack temperature due to burning a larger quantity of fuel oil
than should be necessary. Conservation of fuel oil is thus closely linked
with furnace design.

HENRY P. MUELLER, f St. Louis, Mo. I am connected with a bras
foundry that makes 15 tons of metal daily, burning 1000 gal. of oil. In
the last ten years we have tried practically every burner on the market,
but the most satisfactory was one we designed. The oil is discharged
as a spray under 2^-lb. pressure; the air comes out of the lj^-in. open-
ing and breaks up the oil at the end of the burner, throwing it 18 in.
before it enters the furnace.

Some of our burners are running under compressed air, which in
some .cases is more economical than steam. The oil is run into the
tanks under air pressure and is left in circulation; as a result, it] is
unnecessary to clean a burner or pipe.

The furnace is of the revolving type. The flame does not come
into contact with the metal; instead it heats the top of the furnace,
then as that is revolved under the charge, the metals are melted with
a loss of only 1J^ per cent.

The cost of melting metal on a normal market is 14 cents; today
we are paying 10 cents per gallon for oil in carload lots, therefore the
cost of melting is practically doubled.

JOHN L. HENNING, Lake Charles, La. In burning oil we have not
had much difficulty in getting proper atomization. The furnace design
is the most important thing. We used a common burner and tried to
get a happy medium between good combustion and long lived furnace.
We burned Mexican oil straight without any trouble with that type
burner. When the price of kerosene was low, we burned it in the same
burners, simply letting it run out, and got as good combustion as with
crude oil under the best conditions.

* Chief Chemist, Roxana Petroleum Corpn.
f President, Mueller Brass Foundry.

574 EFFICIENCY IN USE OF OIL AS FUEL

ARTHUR KNAPP, Shreveport, La. In burning oil in small quantities
it is necessary to remember that oil must be brought into a condition to
ignite; that is, each particle must be vaporized before it will burn. When
burning a small quantity, as trying to fire a 10-hp. boiler or smaller, it
is necessary to have a large surface that will radiate sufficient heat to
vaporize the oil and ignite the vapor. In large furnaces, large radiating
surfaces above or to the side of the burner furnish the required heat.

W. N. BEST (author's reply to discussion). While it is important
to have the furnace properly designed, if the oil burner will not function
with the furnace design, there will be inefficient combustion; vice versa,
if the furnace is improperly designed, the most efficient and most modern
type of burner will be a failure.

Mr. Mathews is perfectly correct in his premises of a proper design
of furnace, but it is just as essential to have a burner that will not
carbonize; that will atomize any gravity of liquid fuel; that does not re-
quire excessive oil pressure. It is very important, in burning heavy oil
or tars to use low oil pressure. Oil or tar should never be burned under
an oil or tar pressure exceeding 12 lb., using an atomizing burner.

In the melting of brass it is absolutely essential to have a properly
designed furnace; to have a combustion chamber of adequate proportions
to insure the consumption of the atomized fuel and the reduction of it
to heat before it reaches the furnace proper; to have a burner that will
make a flame to fit the combustion chamber as perfectly as a drawer fits
an opening in a desk. Without the combustion chamber the furnace will
not function properly, owing to the fact that there will be an excessive
amount of unmixed air entering the furnace, which will result in an exces-
sive loss of metal.

INDEX

[NOTE. In this Index the names of authors of papers are printed in small capitals,
and the titles of papers in italics.]
Accumulation, oil, salt domes, Gulf coastal plain, 319.
Alabama: coal, carbon ratios, 141, 146.
map, geological, 141.
oil horizons, 143.
oil possibilities, 140.
stratigraphy, 141.
Alag6as, Brazil, oil-shale, 71.
ALBERTSON, M.: Isostatic Adjustments on a Minor Scale, in their Relation to Oil

Domes, 418.

ALVEY, GLENN H. and FOSTER, ALDEN W.: Barrel-day Values, 412.
AMBROSE, A. W. : Analysis of Oil-field Water Problems, 245.

Discussions: on Investigations Concerning Oil-water Emulsion, 454.

on Value of American Oil-shales, 235.
Amortization: definition, 374.

oil property investment, 350.
Analysis: coal, 525.

oil and gas sands, 495.
water in oil wells, 253.
Analysis of Oil-field Water Problems (AMBROSE). 245; Discussion: (CONKLING), 265,

267; (DEGOLYER), 265, 266; (REILLEY), 266; (MILLS), 266, 267.
ANDROS, S. O. : Discussion on Efficiency in Use of Oil as Fuel, 572.
Anglo-Persian Oil Co., 9.
Appalachian oil fields, geology, 151.
Application of Law of Equal Expectations to Oil Production in California (BEAL and

NOLAN), 335.
Application of Taxation Regulations to Oil and Gas Properties (Cox), 374; Discussion:

(ARNOLD), 393.

Appraisal, oil property, method, 356.

Appraisal of Oil Properties (OLIVER), 353; Discussion: (BEAL), 361; (JOHNSON), 363.
Argentina, oil, see Oil, Argentina.
ARNOLD, RALPH: Discussions: on Application of Taxation Regulations to Oil and Gas

Properties, 393.

on Oil-shales and Petroleum Prospects in Brazil, 76.
on Petroleum Industry of Trinidad, 67, 68.
on Variation in Decline Curves of Various Oil Pools, 373.
ASHLEY, G. H. : Discussions: on A Resume of Pennsylvania-New York Oil Field, 154.

on Water Displacement in Oil and Gas Sands, 501, 502.
Asphalt, related hydrocarbons, 217.
Asphaltenes and asphaltites, definitions, 217.

575

576 INDEX

Bahia, Brazil, oil-shale, 72.

Baku oil fields: casing records, 464.

drilling, 30, 459.

production technique, 31, 459.

well characteristics, 459, 460. .

yield, 33.

Barrel-day Values (ALVEY and FOSTER), 412; Discussion: (JOHNSON), 416.
Barrel-time curves, oil-well depletion, 406.
BASKERVILLE, CHARLES: Value of American Oil-shales, 229.
BATES, Mo WRY: Discussion on Oil Possibilities in Northern Alabama, 150.
BEAL, CARL H. : Essential Factors in Valuation of Oil Properties, 344.

Discussions: on Appraisal of Oil Properties, 361.

on Variation in Decline Curves of Various Oil Pools, 370.
BEAL, CARL H. and NOLAN, E. D.: Application of Law of Equal Expectations to Oil

Production in California, 335.

BEST, W. N.: Efficiency in Use of Oil as Fuel, 568; Discussion, 574.
Big Sinking oil pool, Kentucky, 168.
Biography, Anthony F. Lucas (GOODRICH), 421.
Bitumen: definition, 217.

derivatives, 217.

Philippines, 54.

Bottom settlings, oil wells, definition, 430, 458.
BOWNOCKER, J. A. : Rise and Decline in Production of Petroleum in Ohio and Indiana,

108.

BRADLEY, OLIVER U. : Valuation Factors of Casing-head Gas Industry, 395.
BRANNER, J. C. : Discussion on Oil-shales and Petroleum Prospects in Brazil, 76.
Brazil: oil, 69, 76.

oil-shales, 69.

petroliferous rocks, 241.
Brines: oil-field, origin, 269, 282.

solubility of gypsum, 273.

solubility of limestone, 275.
B. S., definition, 430, 458.

photomicrographs, 433, 434, 436.

water content, 438, 458.
Burners, oil, 570.

California, oil, production curves, 335, 339.

Carbon ratios, coal, 525.

Carbon Ratios of Coals in West Virginia Oil Fields (REGER), 522, Discussion: (SiNGE-

WALD), 526.

Carbonaceous matter in oil-forming rocks, 177.

Carbonization state of organic matter in oil-bearing formations, 179.
Casing-head gas : composition, 397.

contracts for purchase, 400.

efficiency of plant, 399.

estimate of costs, 400.

investment value, 395.

market quotations, 404.

oil-lease connection, 398.

plant efficiency, 399.

plant location, 398.

price schedule, 492.

INDEX 577

Casing-head gas: quality, 397.

quantity available, 396.
valuation factors, 395.
Casing-head gasoline, importance, 395.
Casing records, Baku oil fields, 464.
Cement oil field, Oklahoma: comparison with other fields, 160.

Cyril gypsum bed, 158.

deep sands, positions, 161.

geological structure, 159.

history of development, 157.

stratigraphy, 158.

topography , 156.
CLAPP, FREDERICK G.: Geology of Cement Oil Field, 156.

Discussion on Secondary Intrusive Origin of Gulf Coastal Plain Salt Domes, 324.
Classification: oil, 505.

rock, oil drilling, 424, 428.
Climatic factor in origin of oil, 212.
Clinton sand fields, Ohio, petroleum, 113, 119.
Coal: Alabama, carbon ratios, 141, 146.

analyses and carbon ratios, 525.

carbon ratios, 522, 525.

cost, compared with oil, 571.

distillation, products, 219, 224.

formation, theory, 221, 224.

insoluble portions, relations, 221.

nature, 217, 221.

prices, comparison with oil prices, 553.

soluble portions, relations, 219.
Cobalt, Ont., dome formation in lake, 418.

COLLOM, R. E. : Discussion on Investigations Concerning Oil-water Emulsion, 458.
Comodoro Rivadavia oil field, 42.
Composition of Petroleum and its Relation to Industrial Use (MABERY), 505; Discussion:

(SADTLER), 518; (TILLSON), 520; (MABERY), 521.
CONKLING, R. A. : Discussions: on Analysis of Oil-field Water Problems, 265, 267.

on Industrial Representation in the Standard Oil Co. (N. /.), 239.

on Oil-field Brines, 290.

on Petroleum Industry of Trinidad, 68.
Corniferous limestone, Indiana, petroleum, 115.
COSTE, EUGENE : Discussion on Secondary Intrusive Origin of Gulf Coastal Plain Salt

Domes, 322.
Costs: fuel, coal and oil, 571.

oil: American and Mexican fields, 554.

transportation, Mexican, 539.
COTTRELL, F. G.: Discussion on Investigations Concerning Oil-water Emulsion, 455,

456.

Cox, THOMAS: Application of Taxation Regulations to Oil and Gas Properties, 374.
Cyril gypsum bed, Oklahoma, 158.

Decline curves, oil fields, variation, 365.

Deductions, oil and gas property taxation, 375.

DEGOLYER, E.: Discussions: on Analysis of Oil-field Water Problems, 265, 266.

on Nature of Coal, 223.

on Oil-field Brines, 287, 288.

578 INDEX

DEGOLYBR, E. : on Oil Fields of Persia, 15.

on Petroleum Industry of Trinidad, 67, 68.

on Petroleum in the Argentine Republic, 44.

on Secondary Intrusive Origin of Gulf Coastal Plain Salt Domes, 325.
Demulsification, oil, electrical, 456.

DE OLIVEIRA, EUZEBIO P.: Petroliferous Rocks in Serra de Baliza, 241.
Depletion: computation, oil and gas properties, 382.

oil wells, curves, 405.
Deposition, oil, conditions, 194.
Depreciation, definition, 374.
Determination of Pore Space of Oil and Gas Sands (MELCHER), 469; Discussion:

(MILLS), 490, 491; (SMALL), 490; (WASHBURNE), 497.
Diasphaltenes, definition, 217.

Displacement of water in oil and gas sands, 498, 499.
Distillation: coal, products, 219, 224.

oil-shales, outline, 230.

Dollar-time curves, oil-well depletion, 405, 406, 407.
Domes: formation in Cobalt Lake, 418.

oil, formation, 418.

salt, see Salt domes.
Drilling, oil: Appalachian field, 153.

Baku fields, 459.

rock classification, 424, 428.

Russia, 30, 37, 38.

Russian machinery, 462, 463.

Trinidad, 62.
Drilling and Production Technique in the Baku Oil Fields (KNAPP), 459; Discussion:

(KNAPP), 466.

Dryness, oil strata, 498, 501.
DUCE, J. F. : Discussion on Genetic Problems Affecting Search for New Oil Regions, 197.

Efficiency in Use of Oil as Fuel (BEST), 568; Discussion: (ANDROS), 572; (MAT-
THEWS), 573; (MUELLER), 573; (HENNING), 573; (KNAPP), 574, (BEST), 574.
Electrical demulsification, oil, 456.
Employees' conferences, Standard Oil Co., 238.
Employees' insurance, 240.
Emulsion, oil-water, see Oil-water emulsion.
Equal expectations, law, oil production, 335.
Essential Factors in Valuation of Oil Properties (BEAL), 344.
Exports, Mexican petroleum, 532, 533.

Family curve, oil-well production, 335, 343.
Folding of strata, oil genesis, 182.

Foreign Oil Supply for the United States (SMITH), 89; Discussion: (REQOA), 93; (WASH-
BURNE), 94; (JOHNSTON), 95.
FOSTER, ALDEN W. and ALVEY, GLENN H.: Barrel-day Values, 412.

GARFIAS, V. R. : General Notes on the Production, Marine Transportation, and Taxation

of Mexican Petroleums, 528.
Gas: casing-head, see Casing-head gas.
helium content, 503, 504.
movement: Louisiana, 502.
McKeesport gas pool, 501.

INDEX 579

Gas: sands, see Oil and gas sands.

wells, depletion, computation, 384.
Gasoline: natural-gas, Pennsylvania, 153.

production, 513.

use, 513.
General Notes on the Production, Marine Transportation, and Taxation of Mexican

Petroleums (GARFIAS), 528.
Genesis, oil: carbonaceous matter in the oil-forming rocks, 177.

deposition conditions, 194.

folding of strata, 182.

state of carbonization of organic matter in oil-bearing formations, 179.

thickness of sedimentary formations, 192.
Genetic Problems Affecting Search for New Oil Regions (WHITE), 176; Discussion:

(JOHNSON), 195; (HIXON), 195, 197; (REGER), 196, 197; (Dues), 197.
Geology, oil: Alabama, 141.

Cement field, Oklahoma, 156.

Irvine district, Kentucky, 165.

Kansas, 100.

Kentucky, 127.

Pennsylvania-New York field, 151.

Persia, 11.

Philippines, 48.

Russia, 21.

Tennessee, 123.

Trinidad, 60.

Geology of Cement Oil Field (CLAPP), 156.
GLENN, L. C.: Oil Fields of Kentucky and Tennessee, 122.
GOODRICH, H. B.: Biography of Anthony F. Lucas, 421.
Great Britain, oil resources, 3.
Gulf coastal plain, salt domes, origin, 295.
Gypsum: origin in Red Beds, 274.

origin in salt domes, 272, 285.

solubility in sodium chloride solutions, 273.

HACKFORD, F. E.: Nature of Coal, 217.
Hardstoft oil wells, Great Britain, 5.
Hartselle sandstone, Alabama, oil possibilities, 144, 150.
Helium, presence in natural gas, 503, 504.

HENNING, JOHN L.: Discussion on Efficiency in Use of Oil as Fuel, 573.
HEROLD, STANLEY C.: Petroleum in the Argentine Republic, 40; Discussion, 45.
HICKS, CLARENCE J.: Industrial Representation in the Standard Oil Co. (N. /.), 237.
HEXON, H. W. : Discussions: on Genetic Problems Affecting Search for New Oil Regions,
195, 197.

on Secondary Intrusive Origin of Gulf Coastal Plain Salt Domes, 329.

on Water Displacement in Oil and Gas Sands, 503.
HUNTER, CAMPBELL M.: Oil Fields of Persia, 8.
HUNTLEY, STIRLING and JOHNSON, ROSWELL H.: A Resume of Pennsylvania-New

York Oil Field, 151.
Hydrocarbons: oil components, 506.

petroliferous, 217.

Indiana, petroleum, production rise and decline, 110.

Industrial Representation in the Standard Oil Co. (N. J.) (HICKS), 237; Discussion:
(CONKLING), 239; (PRATT), 240.

580 INDEX

Insurance, employees', 240.

International Aspects of the Petroleum Industry (MANNING), 78; Discussion: (WALDO),

87.

Investigations Concerning Oil-water Emulsion (McCoy, SHIDEL and TRAGER), 430;
Discussion: (AMBROSE), 454; (TRAGER), 454, 455, 456, 457; (MOORE),
454, 455, 457; (WASHBURNE), 455, 457; (COTTRELL), 455, 456: (COLLOM),
458.

Irvine Oil District, Kentucky (ST. CLAIR), 165.
Irvine oil district, Kentucky: Big Sinking pool, 168.
economic conditions, 172.
extension of eastern fields, 169.
geology, 165.
location, 165.
map, 171.

occurrence of oil, 167.
Isocarb: definition, 147, 522.
West Virginia, 147, 522.

Isostatic Adjustments on a Minor Scale, in their Relation to Oil Domes (ALBERTSON),
418.

JOHNSON, ROSWELL H.: Variation in Decline Curves of Various Oil Pools, 365; Discus-
sion, 373.

Water Displacement in Oil and Gas Sands, 498.
Discussions: on Appraisal of Oil Properties, 363.
on Barrel-day Values, 416.

on Genetic Problems Affecting Search for New Oil Regions, 195.
on Modified Oil-well Depletion Curves, 411.
on Water Displacement in Oil and Gas Sands, 502, 503.
JOHNSON, ROSWELL H. and HUNTLEY, STIRLING: A Resume of Pennsylvania-New

York Oil Field, 151.
JOHNSTON, R. H.: Discussion on a Foreign Oil Supply for the United States, 95.

KANSAS: oil, see Oil, Kansas.

Pennsylvanian rocks, divisions, 102.

Permian rocks, divisions, 104.

stratigraphy, 100.
Kentucky: oil, Irvine district, 165.

oil fields, 124.
Kerites: definitions, 218.

soluble, relations with soluble portions of coal, 219.
Kerotenes, kerols, keroles, and kerites, definitions, 218.
KNAPP, ARTHUR: Drilling and Production Technique in the Baku Oil Fields, 459.

Modified Oil-well Depletion Curves, 405.

Rock Classification from the Oil-driller's Standpoint, 424.

Discussions: on Efficiency in Use of Oil as Fuel, 574.
on Oil Fields of Russia, 37.
on Petroleum Industry of Trinidad, 68.

KNAPP, I. N. : Discussion on Drilling and Production Technique in the Baku Oil Fields,
466.

Labor policy, Standard Oil Co., 237.

Law of equal expectations, oil production, 335.

Lease status-time curves, oil-well depletion, 405, 406, 407.

INDEX 581

Limestone caps, origin, 274, 285.

Limestone: solubility in sodium chloride solutions, 275.

solution and deposition in sands, 276.
Lubricants: production, 514.

use, 514, 520.

viscosity and quality, 520, 521.
Lucas, Anthony F., biography, 421.

MABERY, CHARLES F. : Composition of Petroleum and its Relation to Industrial Use

505; Discussion, 521.

MACREADY, GEORGE A. : Petroleum Industry of Trinidad, 58.
MADGWICK, T. G. and THOMPSON, A. BEEBY: Oil Fields of Russia, 17.
MANNING, VAN H.: International Aspects of the Petroleum Industry, 78.
Map: Alabama, geological, 141.

Irvine oil district, Kentucky, 171.

Mid-Continent oil field, 98.

North American petroliferous provinces, 202.

Ohio, oilfields, 116.

Persia, oil fields, 10.

Trinidad, oil fields, 59.
Maranhao, Brazil, oil-shale, 70.
Marine origin of oil, 208.
MATTESON, W. G. : Secondary Intrusive Origin of Gulf Coastal Plain Salt Domes, 295

Discussion, 327, 331.

MATTHEWS, RALPH R. : Discussion on Efficiency in Use of Oil as Fuel, 573.
McCoY, ALEX. W., SHIDEL, H. R. and TRACER, E. A.: Investigations Concerning

Oil-water Emulsion, 430.
McKeesport gas pool, gas movement, 501.

MELCHER, A. F. : Determination of Pore Space of Oil and Gas Sands, 469.
Mexico: distance to American ports, 541.

foreign oil companies, 530.

measurement of petroleum, 531.

oil, see Oil, Mexico.

taxation, see Oil, Mexico, taxation.

units of measurement, 531.
Mid-Continent oil field, map, 98.
MILLS, R. VAN A. : Discussions: on Analysis of Oil-field Water Problems, 266, 267.

on Determination of Pore Space of Oil and Gas Sands, 490, 491.

on Oil-field Brines, 281, 286, 288, 289, 290.

on Petroleum Industry of Trinidad, 67.

on Secondary Intrusive Origin of Gulf Coastal Plain Salt Domes, 329.
Modified Oil-well Depletion Curves (KNAPP), 405; Discussion: (JOHNSON), 411.
MOORE, RAYMOND C. : Petroleum Resources of Kansas, 97.
MOORE, R. W. : Discussion on Investigations Concerning Oil-water Emulsion, 454,,

455, 457.

Movement of oil, water, and gas in displacement, 499.
MUELLER, HENRY P.: Discussion on Efficiency in Use of Oil as Fuel, 573.

National Petroleum Co., Philippines, 49.

Natural gas, Pennsylvania, 153.

Natural-gas gasoline, Pennsylvania, 153.

Nature of Coal (HACKFORD), 217; Discussion: (PRATT), 223; (WHITE),

(DEGOLYER), 223; (THIESSEN), 224; (WATERS), 227.
NELSON, WILBUR A. N. : Discussion on Oil Fields of Kentucky and Tennessee, 134

582 INDEX

New York, oil, 151.

NOLAN, E. D. and BEAL, CARL H.: Application of Law of Equal Expectation* to Oil

Production in California, 335.
North America, map, petroliferous provinces, 202.
North Argentine-Bolivian oil field, summary, 40.

Ohio: map, oil fields, 116.
oil: composition, 511.

production rise and decline, 110.

Oil: accumulation, salt domes, Gulf coastal plain, 319.
Alabama: development, 148.

future prospecting, 149.

geology, 141.

Hartselle sandstone, 144, 150.

horizons, 143.

possibilities, 140.

structural features, 146.
Anglo-Persian Oil Co., 9.
Argentina: Comodoro Rivadavia district, 42.

Gallegos-Punta region, 44.

Government reservations, 45.

localities, 40.

Mendoza and Neuquen provinces, 41.

North Argentine-Bolivian field, 40.

Salta-Jujuy district, 41.
atomizing burners, 570.
Baku fields, 30, 31, 33, 459.
Big Sinking pool, Kentucky, 168.
Brazil, 69, 76, 242.
burners, 570.

Carboniferous strata, 201.
classification, 505.
climatic factor in origin, 212.
commercial products, preparation, 512.
components: hydrocarbons: aromatic, 508.
basic series, 506.
ethylene series, 507.
methane series, 506.

nitrogen bases, 509.

oxygen compounds, 508.

sulfur, 509.
composition, 505.
consumption, U. S., 78, 82.
cost, compared with coal, 571.
costs, Mexican and American fields, 554.
demulsification, electrical, 456.
deposition, conditions, 194.
displacement of water in rock, 499.
drilling, see Drilling, oil.
efficiency in use, 568.
emulsified, see Oil-water emulsion.
exclusion of Americans from foreign fields, 85.
family curve, production, 335, 343.

INDEX 583

Oil: foreign sources of supply, 84.

formation in shale by pressure, 223.

future supply, 89, 92.

gasoline production and use, 513.

genesis, see Genesis, oil.

geology, see Geology, oil.

Great Britain: future prospects, 4.

government regulations, 3.

Hardstoft wells, 5.

political considerations, 3.

Scottish wells, 5.

Hardstoft wells, Great Britain, 5.
importance, 79.
Indiana: Corniferous limestone, 115.

history of development, 108.

production, 109.

rocks, 109.

sandstones, 115.

Trenton limestone, 109.

well records, 112.
industry, 79.
international aspects, 78.
Irvine district, Kentucky, 165.
Kansas: districts, 97.

future possibilities, 106.

geologic section, 101.

history, 97.

map of Mid-Continent field, 98.

production, 99, 105.

stratigraphy, 100.

technology, 105.
Kentucky: districts, 124.

future possibilities, 132, 133, 138.

geology, 127.

history of development, 125.

Onondaga limestone accumulation, 137.

Paint Creek Dome, 133.

structure in relation to occurrence, 129.

technology, 130.
law of equal expectations, 335.
losses, 245.

lubricant, production and use, 514, 520.
manifestations, Russia, 20.
map, North American provinces, 202.
marine origin, 208.
Mexico: companies, 538.

costs, operation, 554.

destinations, 537.

development, 528.

exports, 532, 533.

foreign companies, 530.

grades, 539, 547.

measurement, 531.

584 INDEX

Oil: Mexico: operating costs, 554.
prices, 550.
production, 532, 536.
production per well, 529.
statistics, 532.
tank steamers, 535.
taxation: controversies, 557.
export stamp tax, 546, 548.
former, 545.
grades, 547.
recent, 546.

relation with oil-coal prices, 555.
stamp tax, 546, 548.

transportation: capacity of steamers, 540.
cost of steamers, 542.
costs, 539, 543.

distance to American ports, 541.
tank steamers, 540.
value, 550.

Mid-Continent field, map, 98.
movement in displacement of water in rock, 499.
necessity, 78, 90.

new regions, genetic problems affecting search, 176.
New York: future possibilities, 154.
geology, 151.
grade, 152.

North America, map of provinces, 202.
Ohio: Clinton sand fields, 113, 119.
composition, 511.
history of development, 108.
production, 109.
rocks, 109.
sandstones, 115.
Trenton limestone, 109.
well records, 112.
organic origin, 207.
origin, 199, 204, 207.
Paleozoic strata, 200.
Pennsylvania: drilling, 153.
future possibilities, 154.
geology, 151.
grade, 152.
history, 151.

Persia: Anglo-Persian Oil Co., 9.
geology, 11.

history of development, 8.
map of fields, 10.
occurrence, 8.
production, 15.
technology, 14.

Philippines : history of development, 49.
National Petroleum Co., 49.
properties, 53.

INDEX 585

Oil: Philippines: stratigraphy, 48.

prices : comparison with coal prices, 553.

future, 347.

Mexican and American, 552.
production: U. S., 82, 232, 532.

world's, 532.

production methods, Baku, 31.
provinces, 199, 205, 215.
refining, method, 512.
requirements, U. S., 232.
resources, world's, 81.
scientific work, value, 517.
Scotland, 5.

segregation above water, 279.
sources, 199, 204, 207, 517.
substitutes, 83.
sulfur content, 509.
supply: foreign, 84, 89.

future, 89, 92.
supply lines, 569.

taxation, relation with oil-coal prices, 555.
temperature in use, 569.
Tennessee: geology, 123.

history, 122.
transportation: costs, 539.

Mexico, 539.
Trinidad: character, 63.

drilling, 62.

future possibilities, 64.

geology, 60.

map of fields, 59.

occurrence, 61.

production, 60, 63.

technology, 62.

transportation, 64.
use: burners, 570.

cost, 571.

efficiency, 568.

furnace design, 572, 574.

supply lines, 569.

temperature, 569.
uses, 80.

value of American shales, 229.
West Virginia, limits, 524.
world's production, 532.
Oil and gas areas, West Virginia, 523.

Oil and gas properties, taxation, see Taxation^ oil and gas properties.
Oil and gas sands : analyses, 495.
dryness, 498, 501.
migration of oil and water, 492.
pore space, see Pore space, oil and gas sands.
water displacement, 498.
Oil companies, Mexico, 538.

586 INDEX

Oil drilling, see Drilling, oil.
Oil-field brines, origin, 269, 282.

Oil-field Brines (WASHBURNE), 269; Discussion: (MILLS), 281, 286, 288, 289, 290;
(DEGOLYER), 287, 288; (PRATT), 289; (CONKLING), 290; (WASHBURNE),
290.

Oil-field water problem: data for analysis, 248.
field tests, 252.
maps and cross-sections, 249.
Oil fields: Appalachian, geology, 151.
appraisal, 344, 353.
decline curves, variation, 365.
fraudulent stock promotion, 354.
Mexico, development, 528.
Mid-Continent, map, 98.
Ohio, map, 116.

Oklahoma, cement field, geology, 156.
Russia: Baku fields, 30, 31, 33.
disposal of oil, 19.
drilling, 30, 37, 38.
geology, 21.
history, 17.
leasing, 19.

manifestations of oil, 20.
oil occurrence, 26.
production, 33, 37.
production methods, 31.
relative importance, 36.
stratigraphy, 21.
structure, 25.
yields, 33, 37.
speculation, 353.
Trinidad, 58.

valuation, factors influencing, 344, 359.
value, 353, 355.

Oil Fields of Kentucky and Tennessee (GLENN), 122; Discussion: (SEARS), 133; (NEL-
SON), 134; (ST. GLAIR), 137.

Oil Fields of Persia (HUNTER), 8; Discussion: (DEGOLYER), 15; (WHITE), 16.
OU Fields of Russia (THOMPSON and MADGWICK), 17; Discussion: (KNAPP), 37;

(THOMPSON), 38.
Oil Possibilities in Northern Alabama (SEMMES), 140; Discussion: (WHITE), 150;

(BATES), 150.

Oil properties, valuation, see Valuation, oil properties.
Oil-shales: American, value, 229.
Brazil: Alag6as, 71.
Bahia, 72.
Maranhao, 70.
Sao Paulo, 74.
southern Brazil, 74.
caking and non-caking, 231.
characteristics, 231.
definition, 229.
distillation, outline, 230.
industry, present development, 83.

INDEX 587

Oil-shales: nature, 226.

requirements for economic value, 230.
treatment: American, 231.

history, 229.

Scotch, 233.

yield for a productive field, 209.
Oil-shales and Petroleum Prospects in Brazil (WILLIAMS), 69; Discussion: (ARNOLD),

76; (WHITE), 76; (THOMAS), 76; (BRANNBR), 76.
Oil strata, dryness, 498, 501.

Oil- water emulsion : bottom settlings, 430, 438, 458.
B. S., definition, 430, 458.
bubbles, 431.
classes, 437.
definition, 433.
distillation results, 441.
electrical treatment, 455, 456.
investigations: apparatus, 439.

field, 441.

laboratory, 430.
permanent, 437.

photomicrograph, 431, 432, 435.
physico-chemical properties, 437.
production diagrams, 444.
size of bubbles, 431.
water content, 438, 458.
Oil-well depletion curves, 405.
Oil wells: bottom settlings, definition, 430, 458.
buckets, diagram, 443.
depletion, computation, 382.
diagram, working parts, 442.
erratic, 341.

family curve, production, 335, 343.
future production : curves, 338, 340.

estimation, 342.
law of equal expectations, 335.
life, determination, 340.
persistence, 372, 373.

production curves, 335, 338, 340, 341, 365.
production diagrams, oil-water emulsion, 444.
production during decline, 365.
productivity, pore space effect, 479.
water: analysis, 253.

analysis of problems, data, 248.

bottom, 263, 265.

correction, 262.

detectors, 256.

edge, 264.

effect on production, 246.

field tests, 252.

intermediate, 263.

maps and cross-sections, 249.

objections, 246.

production diagrams, 444.

588 INDEX

OH wells: water: sources, 246, 259, 267.
top, 262.

working parts, diagram, 442.
Oklahoma: Cement oil field, see Cement oil field, Oklahoma.

Cyril gypsum bed, 158.

OLIVER, EARL: Appraisal of Oil Properties, 353.
Onondaga limestone oil formation, Kentucky, 137.
Organic origin of oil, 207.
Origin: coal, 221, 224.

gypsum in Red Beds, 274.

gypsum in salt domes, 272, 285.

limestone caps, 274, 285.

oil, 199, 204, 207.

oil-field brines, 269, 282.

peat, 224.

salt cores, 270, 285.

salt domes, Gulf coastal plain, see Salt domes, Gulf coastal plain, origin.

PAIGE, SIDNEY: Discussion on Water Displacement in Oil and Gas Sands, 501, 502.

Paint Creek oil dome, Kentucky, 133.

PANYITY, L. S. : Discussion on Rise and Decline in Production of Petroleum in Ohio

and Indiana, 119.

PEARSE, ARTHUR L.: Discussion on Value of American Oil-shales, 233.
Peat, origin, 224.
Pennsylvania: natural gas, 153.

natural-gas gasoline, 153.

oil, 151.

PERRINE, IRVING: Discussion on Petroliferous Provinces, 216.
Persia: map, 10.

oil, see Oil, Persia.
Petroleum Industry of Trinidad (MACREADY), 58; Discussion: (ARNOLD), 67, 68;

(DEGOLYER), 67, 68; (MILLS), 67; (CONKLING), 68; (KNAPP), 68.
Petroleum in the Argentine Republic (HEROLD), 40; Discussion: (DEGOLYER), 44;

(HEROLD), 45.

Petroleum in the Philippines (SMITH), 47; Discussion: (PRATT), 54; (WHITE), 56.
Petroleum Resources of Great Britain (VEATCH), 3; Discussion: (WASHBURNE), 6.
Petroleum Resources of Kansas (MOORE), 97.
Petroliferous hydrocarbons, 217.
Petroliferous Provinces (WOODRUFF), 199; Discussion: (SCHUBERT), 204; (PERRINE),

216; (WASHBURNE), 216.

Petroliferous Rocks in Serra da Baliza (DE OLIVEIRA), 241.
Philippines: bitumens, 54.

correlation of Far Eastern Tertiary, 51.

National Petroleum Co., 49.

oil, 47.

stratigraphy, 48.
Photomicrographs: bottom settlings, oil, 433, 434, 436.

oil-water emulsion, 431, 432, 435.
POGUE, JOSEPH E. : Discussion on Secondary Intrusive Origin [of Gulf Coastal Plain

Salt Domes, 324.
Pore space: building stones, 477.

oil and gas sands : data, 482.

determination: dipping in paraffin, 470.

INDEX 589

Pore space: oil and gas sands: determination: methods, 469.
paraffin method, 470.
pycnometers, 473.
results, 478, 480.
small samples, 474.
volume of individual grains, 472.
volume of sample by weighing, 472.
water absorption method, 477.
nature, 469.

relation to productivity, 479.
water absorption, 477.

Porosity, oil and gas sands, see Pore space, oil and gas sands.
PRATT, W. E.: Discussions: on Industrial Representation in the Standard Oil Co.

(N. /.), 240.
on Nature of Coal, 223.
on Oil-field Brines, 289.
on Petroleum in the Philippines, 54,
Price, future, oil, 347.
Prices, oil and coal, comparison, 553.
Proceedings, St. Louis meeting, 1920, v.
Production curves, oil wells, 335, 338, 340, 341, 365.
Provinces, petroliferous, 199, 205, 215.
Pycnometer, Johnston and Adams, 473.

Red Beds, gypsum origin, 274.

Refining, oil, method, 512.

REGER, DAVID B. : Carbon Ratios of Coals in West Virginia Oil Fields, 522.

Discussion on Genetic Problems Affecting Search for New Oil Regions, 196, 197
Regulations, oil and gas property taxation, 374.
Representation, employees', Standard Oil Co., 237.
REQUA, M. L.: Discussions: on A Foreign Oil Supply for the United States, 93.

on Variation in Decline Curves of Various Oil Pools, 370.
Resume of Pennsylvania-New York Oil Field (JOHNSON and HUNTLEY,) 151; Discussion:

(ASHLEY), 154.
Rise and Decline in Production of Petroleum in Ohio and Indiana (BOWNOCKER), 108;

Discussion: (PANYITY), 119.

Rock Classification from the Oil-driller's Standpoint (KNAPP), 424. 7
Rogers' hypothesis, origin of salt domes, 297.
Russia: geology of oil fields, 21.

oil, production, 33, 37.

oil fields, see Oil fields, Russia.

SADTLER, SAMUEL P.: Discussion on Composition of Petroleum and its Relation to

Industrial Use, 518.
ST. CLAIR, STUART: Irvine Oil District, Kentucky, 165.

Discussion on Oil Fields of Kentucky and Tennessee, 137.
St. Louis meeting, 1920, proceedings, vii.
Salt cores: limestone caps, 274.

origin, 270, 285.

origin of gypsum, 272, 285.
Salt deposits, bedded, Gulf coastal plain, 298.
Salt domes: European, 303.

Gulf coastal plain: analogies with European domes, 303.
oil accumulation, 319.

590 INDEX

Salt domes: Gulf coastal plain: origin: alteration of limestone to gypsum, 315.
deposits underlying, 298.
forces producing intrusion, 302.
formation of domal materials, 307.
gas supply, 310.
intrusive, 297.

movement and uplift, 317, 318.
Rogers' hypothesis, 297.
salt and limestone supply, 311.
secondary deposition, 306.
secondary intrusive, 295, 307, 320.
special characteristics, 304.
theories, 284, 295.

Salta-Jujuy oil district, Argentina, 41.
Sao Paulo, Brazil, oil-shale, 74.

SCHUBERT, CHARLES: Discussion on Petroliferous Provinces, 204.
Scotch oil-shales, treatment, 233.
Scotland, oil, 5.

Search for new oil regions, genetic problems, 176.

SEARS, MORTIMER A. : Discussion on Oil Fields of Kentucky and Tennessee, 133.
Secondary Intrusive Origin of Gulf Coastal Plain Salt Domes (MATTESON), 295;]Z)is-
cussion: (CosTE), 322; (SHAW), 323; (POGUE), 324; (CLAPP), 324; (DE-
GOLYER), 325; (MATTESON), 327, 331; (HEXON), 329; (MILLS), 329.
Segregation of oil above water, 279.

SEMMES, DOUGLAS R.: Oil Possibilities in Northern Alabama, 140.
Serra da Baliza, petroliferous rocks, 241.
Shale, oil see Oil-shale.
SHAW, E. W. : Discussions: on Secondary Intrusive Origin of Gulf Coastal Plain Salt

Domes, 323.

on Water Displacement in Oil and Gas Sands, 502.
SHIDEL, H. R., McCoy, ALEX. W., and TRACER, E. A.: Investigations Concerning

Oil-water Emulsion, 430.
SINGEWALD, J. T., JR.: Discussion on Carbon Ratios of Coals in West Virginia Oil

Fields, 526.

SMALL, W. M.: Discussion on Determination of Pore Space of Oil and Gas Sands, 490.
SMITH, GEORGE OTIS: A Foreign Oil Supply for the United States, 89.
SMITH, R. A.: Discussion on Value of American Oil-shales, 236.
SMITH, WARREN Du PRE: Petroleum in the Philippines, 47.
Solubility: calcium bicarbonate in sodium chloride solutions, 275.

calcium sulfate in sodium chloride solutions, 273.
Speculation, oil fields, 353.
Standard Oil Co.: conferences, works, 238.
industrial representation, 237.
insurance, employees', 240.
labor policy, 237.
Substitutes, oil, 83.
Sulfur, in petroleum, 509.

Tank steamers, Mexican petroleum, 535
Taxation: Mexico, controversies, 557.

oil: Mexico, see Oil, Mexico, taxation
relation with oil-coal price, 555.

oil and gas properties: accounts, 375.

INDEX 591

Taxation: oil and gas properties: ad valorem basis, 393.
allowances, 375, 378, 387.
capital invested, 379.
capital sum, 381.
. depletion, 382.
depreciation, 387.
invested capital, 379.
items not deductible, 391.
proof of discovery, 378.

quantity of oil in ground, determination, 381.
records, 392.

recoverable reserves, 382.
regulations, 374.
revaluation, 377.

surplus and undivided profits, 379.
Treasury Department Manual, suggestions, 387, 388.
valuation, 376.
Tennessee, oil fields, 122.

THIESSEN, REINHARDT: Discussion on Nature of Coal, 224.

THOMAS, J. ELMER: Discussion on Oil-shales and Petroleum Prospects in Brazil, 76.
THOMPSON, A. BEEBY: Discussion on Oil Fields of Russia, 38.
THOMPSON, A. BEEBY and MADGWICK, T. G. : Oil Fields of Russia, 17.
TILLSON, B. F.: Discussion on Composition of Petroleum and its Relation to Industrial

Use, 520.
TRACER, E. A.: Discussions: on Investigations Concerning Oil-water Emulsion, 454,

455, 456, 457.

OTi Value of American Oil-shales, 234, 235.
TRACER, E. A., McCoY, ALEX. W., and SHIDEL, H. R.: Investigations Concerning

Oil-water Emulsion, 430.

Treasury Department Manual, oil and gas property taxation, 387, 388.
Trenton limestone, Ohio and Indiana, petroleum, 109.
Trinidad: geologic column, 65.
map, oil fields, 59.
oil fields, 58.
oil occurrence, 61.
stratigraphy, 60, 65.

Units, measurements, Mexico, 531.
Use: gasoline, 513.
lubricants, 514.

Valuation, oil properties: amortization, 350.
barrel-day values, 412.
costs, 348.

depletion curves, 405, 409.
drilling program, 346.
establishment for taxation, 376.
factors, 344, 359.
future expectation, 345.
future price of oil, 347.
interest on investment, 349.
land classification, 346.
method, 356.
"paying out," 412.

592 INDEX

Valuation, rate of production, 345.

salvage value of equipment, 352.

Valuation Factors of Casing-head Gas Industry (BRADLEY), 395.
Value, oil fields, 353, 355.
Value of American Oil-shales (BASKERVILLE), 229; Discussion: (PEARSE), 233; (TRA-

GER), 234, 235; (WASHBURNE), 234, 235; (AMBROSE), 235; (SMITH), 236.
Variation in Decline Curves of Various Oil Pools (JOHNSON), 365; Discussion: (REQUA),

370; (WASHBURNE), 370; (BEAL), 370; (JOHNSON), 373; (ARNOLD), 373.
VEATCH, A. C. : Petroleum Resources of Great Britain, 3.
Viscosity, lubricants, relation to quality, 520, 521.

WALDO, LEONARD: Discussion on International Aspects of the Petroleum, Industry, 87.
WASHBURNE, CHESTER W.: Oil-field Brines, 269; Discussion, 290.

Discussions: on Determination of Pore Space of Oil and Gas Sands, 497.
on A Foreign Oil Supply for the United States, 94.
on Investigations Concerning Oil-water Emulsion, 455, 457.
on Petroleum Resources of Great Britain, 6.
on Petroliferous Provinces, 216.
on Value of American Oil-shales, 234, 235.
on Variation in Decline Curves of Various Oil Pools, 370.

Water Displacement in Oil and Gas Sands (JOHNSON), 498; Discussion: (WHITE), 501,
504; (ASHLEY), 501, 502; (PAIGE), 501, 502; (JOHNSON), 502, 503; (SHAW),
502; (HIXON), 503.

Water invasion, oil wells: analysis of water, 253.
bottom, 263, 265.
correction, 262.
detectors, 256.
edge water, 264.
effect on production, 246.
field tests, 252.
indications, 258.
intermediate, 263.
maps and cross-sections, 249.
objections, 246.
sources, 246, 259, 267.
top water, 262.

Water-oil emulsion, see Oil-water emulsion.
WATERS, C. E.: Discussion on Nature of Coal, 227.
Well logs: interpretation, 424.

rock types, 424.
West Virginia: coal, carbon ratios, 522, 525.

map, isocarb lines and oil and gas areas, 523.
oil, limits, 524.
oil and gas areas, 523.

WHITE, DAVID: Genetic Problems Affecting Search for New Oil Regions, 176.
Discussions: on Nature of Coal, 223.
on Oil Fields of Persia, 16.
on Oil Possibilities in Northern Alabama, 150.
on Oil-shales and Petroleum Prospects in Brazil, 76.
on Petroleum in the Philippines, 56.
on Water Displacement in Oil and Gas Sands, 501, 504.
WILLIAMS, HORACE E.: Oil-shales and Petroleum Prospects in Brazil, 69.
WOODRUFF, E. G. : Petroliferous Provinces, 199.