The East Texas Oil Field

By FREDERIC H. LAHEE," DALLAS, TEXAS

(Houston Meeting, October, 1931)

AFTER abandoning two dry holes, on the Mrs. Daisy Bradford land, C. M. Joiner finally completed his No.3 on Sept. 8, 1930, at a total depth of 3592 ft. This well is 7H miles somewhat north of west of the town of Henderson, in Rusk County. Between Oct. 2 and Oct. 6, this well made numerous heads which indicated that it would produce about 300 bbl. daily. By Nov. 27, two dry holes,l completed near the Joiner well, taken in conjunction with the small production from this well, served to dampen any enthusiasm among those who hoped for a major pool; but by December 18 three other producers had been completed. On Dec. 28, 1930, E. W. Bateman's Lois Della Crim No.1 drilled itself in with an estimated daily yield of between 10,000 and 15,000 bbl. from a depth of 3650 ft. This well, 10 miles north of the Joiner well, Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021 also in Rusk County, initiated the leasing campaign that led to the later orgy of drilling. On Jan. 25, 1931, Moncrief, Farrell and others com­ pleted their J. K. Lathrop 1 as another big producer, 7 miles east of Gladewater in Gregg County and 14 miles N. 20° E. from the Bateman Crim well. The Lathrop well, 3574 ft. deep, flowed 320 bbl. in 1 hr. through a 7~-in. choke. The first well completed in Smith County was Cook No.1, drilled by Guy Lewis et al. in the Jaffies Jordan Survey, 4.7 miles west of the Joiner discovery well. On Mar. 30, 1931, it flowed 137 bbl. in 33 min, through a %-in. choke. The top of the pay sand was found at 3672 ft. Finally, in Upshur County, on May 5, the Mudge Oil Co. et al. completed the Richardson No.1, which flowed 274 bbl. through a 4%4-in. choke in 2 hr. This well is 4 miles northwest of the Lathrop producer.

DEVELOPMENT

It is unnecessary to give a lengthy description of the rapid develop­ ment of the area discovered in these five far-separated wells, or to discuss the speculations offered as to whether there were several pools or only one .

.. Chief Geologist, Sun Oil Co. 1 Arkansas Fuel Oil Co. Worrell!, east of the Joiner well, and L. L. Smith W. H. Worrell!, north of the Joiner well. 279 280 TilE ~;.'S T T.~ XAS O IL F I t.:Ll>

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1·'10. l.- O UTLISE MAP or EAST TEX"!! 1'001., CONTOURED ON TOI' or WOOOI.

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JUNt J U LY

FIG. 2.-CURVE S OF DlULLING .o\ND PRODUCTION F OR EAST TEXAS FIELD FROM BEGINNING TO SEPT. 17,- 1931.

next 24 weeks (Mar. 25 to Sept. 10), there was an average of about 73 completions each week. By those who had already had experience in the oil industry, the danger of the East Texas situation was early realized. Already in n eeember, 1930, warnings were broadcast as to the effect that might result from unrestrained drilling in this area where a few widely scattered discovery wells had given presage of a large productive area. And furthermore, it was pointed out that this new district, with its easy accessibility, its high-grade oil, and its division into hundreds of owner­ ships, could bring untold disaster if it were not brought under systematic 282 THE EAST TEXAS OIL FIELD control. We all know what happened. We all know that through the ignorance of some and the greed of others here in .East Texas, the whole industry was swept toward the brink of ruin. Efforts toward proration, efforts toward any reasonable form of cooperation failed. No matter what plan was proposed, its practical application seemed impossible of attainment, principally because of the diversity of opinion of those con­ cerned and the fear of some operators that their rights would be infringed upon by others. In early April, the Texas Railroad Commission issued an order provid­ ing a total allowance of 70,000 bbl. for the field, to be gradually increased to 100,000 bbl. By the time the order came out, the field was producing 140,000 bbl. On April 9 the Railroad Commission increased the allow­ ance to 90,000 bbl., but the daily production had incrcased to 195,000 bbl. On "-1ay 7 the allowance was 160,000 bbl. daily, and the actual yield, which the week before had reached 340,000, was reduced by only Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021 70,000 bbl., to 270,000 barrels. '"'V hen thc' first proration order was issued, four major oil companies endeavored to assist the situation by posting a top price of 67 ¢ per barrel. This was early in April. A month previous to that time the price for East Texas crude ranged from 25 to 40 ¢, whereas in October of 1930, oil from the Joiner discovery well had brought $1.10. Finally, about the middle of May, with the failure to enforcc proration on thc relatively few recalcitrants, the posted price was withdrawn, and within three weeks East Texas oil was selling for less than 10~ per barrel. Pro­ duction by June 1 had mounted to 360,000 bbl. per day, and this in the face of the fact that thc Commission's daily allowable was st ill 160,000 bbl. for the field. The average price during June was about 15¢ per barrel. We shall not enter into detail concerning the various activities of committees and organizations to bring the situation under control in June and July. Very worthy efforts were made. However, the real beginning of accomplishment of the end sought was the convening of thc Texas Legislature in special session in the latter part of July, and thc final passing of a bill to give police authority to the Railroad Commission in executing its orders. On August 17, by executive order of Governor Sterling, the East Texas field was completely shut in, anel it remained shut in for 20 days. During this period the Railroad Commission con­ ducted a hearing from August 25 to 28, inclusive, for presentation of engineering data as a basis for formulating its new conservation orders. These new orders were issued on Septcmber 2. Among other things, they called for wider spacing of wells (660 ft.; 330 ft. from property lines); for use of tubing not more than 2~~ in. dia.; for plugging back of wells drilled too deep to a point at least 10 ft. above the water table; for drilling no wells below the top of the pay sand more than two-thirds FREDERIC H. LAHEE 283 of the distance from the top of the sand to the known water level; for limitation of daily production of each well to 225 bbl. j and for production of no well with a gas-oil ratio of over 700 cu. ft. of gas per barrel of oil. Serious criticism of this order was at once offered because, without limiting the total daily yield of the pool, and without limiting the acreage Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021

per well, it was evident that drilling would continue unrestricted as before. We are glad to say, however, that this objection has now been met by the Railroad Commission. On September 11 it amended its order of September 2 by requiring that only one well should be drilled to <'a ell 20 acr<'R of :-;urface ownerRhip; and on September 25 it ordered a 284 THE EAST TEXAS OIL FIELD reduction of the per-well allowable to 185 bbl. daily, thus for the prest'nt holding the field production to less than 400,000 bhl. daily.

GEOLOGY

The East Texas oil pool is situated on the west flank of the Sabine uplift, where the normal regional dip is generally westward (Figs. 1 and 3). The surface formations in the area of the pool belong to the Carrizo, Reklaw and Queen City, all of Tertiary age. These formations, together with those encountered in drilling, are as follows, oldest being at the bottom of the table: Mt S I {Queen City J . e man Reklaw Tertiary...... lCarrizo

Wilcox Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021 Midway Navarro 1Upper Taylor Taylor Pecan Gap (Annona) Upper Cretaceous...... B t rowns own IAustin (Tokio) Woodbine Grayson Lower Cretaceous...... { Georgetown etc. Production is found in sands of the Woodbine formation which, within the field, lies between depths of 3430 and 3800 ft., or between subsea depths of from 3100 to 3150 ft. near the east edge to between 3315 ft. and 3330 ft. on the west edge. As illustrated in Fig. 4, this formation wedges out eastward between the Austin chalk and the George­ town. The thin eastern edge essentially coincides with the eastern boundary of the pool. The Austin formation lies unconformably upon the Woodbine and Lower Cretaceous, and probably also upon the Eagle Ford shale which wedges out west of the west edge of the pool (Fig. 4). The separate members of the Woodbine formation-sands, shales, and volcanic ash-are beveled across by the Austin. As a result of these relations of westward dip and truncation by unconformity, pay sands in the eastern part of the pool are somewhat older than those farther west. On a large scale this is illustrated by Fig. 5, a greatly exaggerated vertical section of conditions in and just above the pay zone in four wells in southeast Smith County. For this reason, the contouring in Fig. 1, based on records of the top of the first producing sand, in the various wells, shows slightly less dip than the true dip of the Woodbine formation. Some of the irregularities in detailed contouring, as in Fig. 6, are undoubt­ edly due to this condition. FIlEDt:lUC H . LAH ~a; 285

With the exception of a possible low flat. closllre 1\ few miles (':lsI. of Gladewater, on the Gladewater anticlinnl nose, l.hNC is no true re\'ersal of the normal westward dip. T he oil has been I ra pped ill the up-dip Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021

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\~\ ~• • "o •• .,- '.. . ,.... . ~,

~ • • • • g • 8 • • ! l , ~ , • ! , • , , , , , •,. , part of the porOlls Wooubine sand where lid" is ll ncon fnl'lll:lbly overlain by impervious beds, or in some instances, perhaps, where local sanus lens out up-dip within the Woodbine formation. 28(; 1'J-Il'.: LAST 'l'BXAS OIL FlBLIJ

\VATEH Downdip, within the pay sand zone, the oil is backed by waLeI' which is under a hydros!"tic head of about 1560 to 1600 lb. per sq. in. With a few local except ions, due to special conditions, the ,va-trc-oil contact ranges brtwcen - :3:-n t,ft,. and - :,:,2;, f1. (Fig. 1). The forlll of this eon(:l.Ct. h~, s noL bCPIl definitely established. It is probably irregular, hut de­ pending on sand porosit.y and I intercalat{-'d shah' lcm;('~ , un­ i 1.\ doubt,pd ly it passe's t'!l:"tward brll('ath the oil in a strip of I ~ r ~\ terri lory, allln~ t.he w('stern

] ~ Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021 , I~I '~\ ~I ' edge of t he pool. No water •< ~ ~ ~ }l ~ ! ~ has heen ellColw tPrcd in the " \Voodbine in t.he eastern part \\ i of the field . Analyses of the f'dge and bottom watcr give an \~ average eonf,ent of between //\ 59,000 an d 69, QOO part,s per million of t 01 al solids. Z I~ \ SAND CONDITIONS 1\ St.udiesof sand samples from •, J~~\ t he Woodbine p"y zone exhibit 6 }/¥A~ I \ \ considerable range in texture, and therefore in effective poros­ ity. In some parts of the field, \~l\ and particularly in the higheror \ younger section of the pay zone, fine volcanic ush occurs both as morc or less recognizable strata ~'llt ~ C 't and also as material distributed "l ' C \~ between the quartz grains of some of the coarser sand layers. o o Under such circumstances the 7 flow of fluids through the sand is less than through sands of coarser texture and larger pore spaces. In a series of tests on samples taken from all parts of the field, a large percentage of the crushed sand

, Compare average sell. water, which run s about 35,000 p.p.m. tota.l solids. [F. W. Clarke: Data of Gcor'.hemistry, Ed. 5 U. S. Geol. Survey Bull. 770 (1924) 127.1 FREDEIUC H. LAHEE 287 passed through screens of 40 to 80 mesh. The percent.age porosity of these sand samples ranged from 26.5 to 31. In spite of the fact that locally the pay zone contains some layers of relatively low effective porosity, there can be no question that this zone Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021

T

.! , ! 4000 FEET

FIG. 6.-DETAIL CONTOUR MAP ON TOP OF PAY SAND IN KILGOHE AHEA. This is included chiefly to illustrate irregularitiekl of key horizon as mapped from available data. Contour interval is 10 feet.

as a whole is relatively very porous, with freedom of communication throughout its greater part. This is demonstrated (1) by the nearly uniform character of the oil over this vast field; (2) by the consistent relations of original reservoir pressures throughout the pool; (3) by the fact, observed in numerous instances, that operations on one well may distinctly affect production and pressure values in other wells, even at 288 THE EAST TEXAS OIL FIELD distances of scyeral hundred feet;3 and (4) by the rapid equalization of reserYoir pressures during the military shutdown in many wells in which pressures had previously been very seriously disturbed by unequal withdrawals. Sand Penetration.-The depth to which wells should penetrate the pay sand depends on the proximity of the water level. It is not con­ sidered good practice to drill below a subsea depth of 3300 ft. (20 ft. above the average water table) unless a greater depth is necessary to reach the pay, and in such cases sand penetration should not be over 5 ft., and preferably less. In parts of the field where the structure is high, wells have been drilled 50 or 100 ft. in the pay and have still been many feet above the water table. According the the Railroad Commission's order of Sept. 2, as we have previously pointed out, penetration of the sand is now limited to two-thirds of the distance from the top of the sand

to the known water level. In the eastern part of the field drilling can­ Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021 not be carried many feet below the top of the sand without passing into Lower Cretaceous shale or lime.

THE OIL Oil from the East Texas pool is of paraffin base. Its average gravity is 39.1 A.P.L, with variations from as low as 38.0 to as high as 40.5. In a majority of the samples examined, the gravity was between 39 and 40 A.P.L Its color is dark brown, especially in the western part of the field, with a tendency toward a somewhat more greenish brown farther east.

TABLE I.-Laboratory Distillation and Analysis of East Texas Crude Oila PEl\CENTAGE OF CRUDE PRODUCT SAMPLE 1 SAMPLE 2 Gasoline (56 0 to 57 0 sp. gr. U.S.M.) ...... 40.7 39.8 Kerosene (40 0 to 41 0 sp. gr.) ...... 1.1 1.5 Gas oiL ...... 22.2 22.3 Lubricating distillate ...... 5.6 5.6 Residuum (19 0 to 20 0 sp. gr.) ...... 27.8 27.9 Fixed gases ...... 1.0 1.0 Loss ...... 1.6 1.9 Wax content is estimated at 2 to 2.5 per cent.

TESTS ON CRUDE SAMPLE SAMPLE 1 SAMPLE 2 Specific gravity...... 39.1 38.7 Sulfur, per cent...... 0.25 0.27 Pourpoint...... 45 a From Oil & Gas Jnl. (June 25, 1931) 98.

3 For example, during the burning of the Grady Bell Daniels 1 well, flowing wide open for 24 days, the flowing tube pressure of the Barnsdall Dee Smith 1 well, 3400 ft. distant, suffered a drop of 75 lb., and, after the former well was brought under control, this pressure in the second well was built up to its former value. FREDERIC H. LAHEE 289 Laboratory distillation of two samples of typical East Texas crudes taken from wells in the Longview-Joiner area is shown in Table 1. These were fractionated at atmospheric pressure in a very efficient tower. Plant yields may be expected to be slightly lower in gasoline. An analysis of the oil is given also in Table 1. In a report recently issued by the U. S. Bureau of Mines, properties of typical crude oils from different sections of the field are discussed. Pourpoints of the samples examined ranged from 25 0 to 45 0 F., suggesting that paraffin trouble may be experienced in cold weather. However, laboratory tests indicated that the paraffin, if it separates out of the oil, may be easily liquefied again by the application of moderate heat. Gas and Gas-oil Ratios.-Measured gas-oil ratios have shown from 100 to 600 cu. ft. of gas per barrel of oil, with an average of about 325 cu. ft. per barrel. This gas contains from 3H to 8 gal. of gasoline per 1000 cu. ft.

It has a relatively low percentage of methane and a correspondingly high Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021 percentage of the heavier gases. An analysis is given in Table 2.

TABLE 2.-Analysis of East Texas Natural Gas"

Gases or Vapors At 0 Lb. I At 33 Lb. I At 50 Lb. I Methane, per cent ...... 49 43.1 36.7 42.7 53.5 Ethane, per cent ...... '...... 11 13.0 14.5 20.2 12.9 Propane, per cent ...... 19 22.3 23.5 21.5 18.3 Isobutane, per cent ...... 3 Butane, per cent ...... 9 13.9 14.9 8.9 10.1 Pentane and heavier, per cent ..... 8 7.7 10.4 3.1 5.2 Nitrogen, per cent ...... 3.6

a From Oil & Gas Jnl. (Sept. 24, 1931) 123. Probably some of the gas occurs as a liquid under the pressures exist­ ing in the pool. The lighter constituents occur dissolved in the oil. There is no accumulation of free gas in the higher parts of the reservoir. Fluid Temperatures.-Temperatures of oil have been reported as low as 89 0 and as high as 1420 at the casinghead. In one water well near the west edge, 1620 was recorded at the bottom of the hole. Probably 1500 to 160 0 F. may be regarded as average temperatures for oil and water in this pool before expansion of dissolved gas has produced cooling. 4 Reservoir Pressure.-Average reservoir pressures for the field as determined by bottom-hole records, range from 1500 to somewhat over 1600 lb. per sq. in., where there has not yet been local depletion due to

4 Compare with maximum temperatures of 125 0 at Mexia, 128 0 at Wortham and 1200 at Powell, where depths to the Woodbine are approximately 2950 ft., 2950 ft., and 2900 ft., respectively. These, however, are records made at the casinghead. (F. H. Lahee: Oil and Gas Fields of the Mexia and Tehuacana Fault Zone, 1,378, Structure of Typical American Oil Fields. Amer. Assn. Petro Geol., 1929.) 290 THE EAST TEXAS OIL FIELD withdrawal of oil. These differences are due to the subsea depth of the sand. With no free gas in the pool, the original reservoir pressure at any given subsea depth is essentially the same. However, since the field was discovered, the rapid and extensive drilling campaign had brought about a decline of reservoir pressure of between 150 and 200 lb. per sq. in. by the end of August. 5 At that time pressures were highest in the Gladewater-Longview area, lowest in the Overton-Joiner area, and inter­ mediate in the Kilgore area. In other words, heavy withdrawals in the southern district had seriously lowered the original reservoir pressure.

WATER ENCROACHMENT The first serious water trouble occurred in April, 1931, in the Burton Drilling Co. Florey 1, and shortly after in the Magnolia Petroleum Co. Florey 1, both near the west edge of the field southwest of Kilgore. On

May 7, 17 wells were reported as making some water. On July 16 this Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021 number had increased to about 30, all producing 1 per cent or more of water. On August 3 there were 32 wells making some water, of which 14 were situated from H to 1 mile east of the west edge of the pool. These 14 wells were yielding water either because they had been drilled too deep or because, by flowing wide open, the water had been coned up from below. By plugging back or by choking down to a smaller daily yield, the water was much reduced or even shut off in some of these wells, so that by Sept. 3 only 22 in the entire pool were reported to be making more than 1 per cent. water. We may say, then, that since the field was opened, water encroachment has not been extensive (Fig. 1). However, the evidence is very strong that uneven water encroachment, with serious consequences, will certainly result unless systematic methods are followed in the spacing, drilling, finishing and producing of wells.

ESTIMATES OF YIELD Our present estimate of the area that will produce oil in the East Texas pool is 92,000 acres. This estimate has been arrived at by two methods. It is considerably less than some of the figures suggested previously. Estimates of average acre-foot yields are subject to wide variation because of the differences in texture, porosity, and stratigraphy in different parts of the field and, indeed, even from well to well. On the basis of an average thickness of 30 ft. of producing oil sand over the entire 92,000 acres, with an average porosity of 25 per cent, and an average extraction of 40 per cent, we should have a total productivity of 775.84 bbl. per acre-foot,6 or 30 X 92,000 X 775.84 bbl. = 2,141,300,000 bbl. for the pool. This amounts to 23,275 bbl. per acre. An average of 15,000 bbl. to the acre would amount to 1,380,000,000 bbl. for the pool.

6 Evidence presented by C. V. Millikan: Oil & Gas Jnl. (Sept. 3, 1931) 79. 6 The volume of an acre-foot = 43,560 cu. ft. = 7758.36 barrels. FHEDEIUC H. LAHEE 291

DRILLING METHODS AND COSTS Drilling in t.he East. Texas field is by rot.ary t.ools. A string of from 250 to 300 ft. of 127~ or 10H-in. surface pipe is set. and cemented. Less than 250 ft. is not recommended. Below this casing, the hole is reduced to either 11 or 9 in., respectively, and is carried down with this size t.o near the top of the pay formation,where 7-in. casing is set and cemented. This string is best seated a few feet above the base of the Austin chalk, which in this area rests on the Woodbine formation and usually either upon or only a few feet above the first pay sand. According to the most satisfactory practice, the hole is cored below the chalk, after setting of the casing, in order to locate the positions of pay sands and shale breaks within the Woodbine. Liner is set through the Woodbine zone, with screen or perforated pipe below the top of the first pay. Where a shale break of considerable thickness lies between two pay sands, blank pipe in the liner may be placed opposite the shale. As required by the Rail­ Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021 road Commission's order of Sept. 2, all wells must be "equipped with and produced through tubing of not more than 2% in. dia.," and further, the tubing string must have its lower end not higher than the top of the producing oil sand. Each well must be equipped with a blow-out pre­ venter before drilling into the pay sand. Estimates of the cost of drilling and completing a well in the East Texas field differ somewhat. In general, it may be said to average about $19,000 for derrick, drilling, casing arid completing with flow connections. To this might be added $4000 for two erected 1000-bbl. stock tanks and certain other equipment, making a total of $23,000 for a completed flowing well.

CROOKED HOLES Because of the great number of leases and lease owners in this field, and the frenzy of many to reach the pay and secure all possible oil in the least possible time, most of the drilling contracts called for speed. As a result, some very fast records were made. The average drilling time to the pay sand, at a depth of 3500 ft. or more, was 10 days. The upper 2500 ft. of sands, sandy shales, and shales above the Pecan Gap chalk, was drilled in some cases in three days. According to one st.atement a certain well was coring the \,yoodbine sand 27.;1: days after it was spudded in. Another instance is that of a crew which drilled 965 ft. in 12 hours. Naturally, crowding the drilling at such rates caused some holes to go crooked. Possibly many are crooked. A few examples may be cited. The first is that of a well drilled in the South Kilgore district. This well should have encountered the bottom of the Austin chalk at about -:3317 whereas actually it reached this horizon at about -3357, or 40 ft. too low. Subsequently, its offset, along the strike, reached the base of the Austin chalk at -3317. A survey of the deeper hole proved that 292 THE EAST TEXAS OIL FIELD it deviated as much as 28° from the vertical, with a horizontal error in location of the bottom of the hole amounting to over 220 ft. and a vertical error of 43 feet. Another example was that of the Universal Oil Co. Brown No.1 well, in the Joiner field. The hole was found to deviate a maximum of 20° from the vertical.7 In the same field, the Imperator Oil Co. Cox No.1, in the R. H. Penny Survey, showed a deviation of 6° at 1000 ft.; 12° at 1500 ft.; 15° at. 2000 ft.; 52° at 2500 ft.; and 75° at 2781 ft.8 About 2 miles northwest of Kilgore, a hole was actually drilled into it ~ offset, ;~oo ft. distant. Finally, we may cite the case of the first hole drilled by Perkins et al. on the l\IcGrade land, 17'2 miles north of the Moncrief et al. Lathrop discovery well. At a depth of 3703 ft. (subsea 3301) this hole encoun­ tered the top of the Pecan Gap chalk, normally 1100 ft. above the pay sand here. The hole ought to have reached the pay sand at about Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021 3220 ft. subsea, as proved by the record of the second hole drilled at the same location. The maximum angle of inclination of the first hole was found to be 45°.

OUTLET On Jan. 8 the Joiner pool had two short 4-in. lines to a lO-car and a 17-car loading rack, on the 1. & G. N. R. R. Early in June announce­ ment was made that pipe lines already constructed and also proposed would be able to take out 500,000 bbl. per day. On Sept. 10 the outlet of the field by trunk pipe lines, tank car loading racks, and local refineries was approximately 1,000,000 bbl. per day.9 It is interesting to compare this figure with the field production limit of approximately 400,000 bbl. daily.

CONCLUSIONS In closing this resume of the discovery and development of the East Texas field, there are several aspects of the situation which may be considered. At the hearing before the Texas Railroad Commission, held at Aust.in last August, the divergence of opinion expressed on certain subjects by engineers and geologists was impressive, for it betokened the inadequacy of our knowledge along certain technical lines and in so doing served to accentuate the need for further collection and study of relevant data. The scarcity of reliable information on the new East Texas pool was natural; but was it not also true that there was some hesitation and difficulty in applying the results obtained in other fields to the East Texas case?

7 Oil & Gas Jnl. (Mar. 5, 1931) 160. 8 Oil & Gas Jnl. (July 16, 1931) 30. 9 Oil & GUll Jnl. (Sept. 10, 1931) 25. FREDERIC H. LAHEE 293 Two lines of thought may be followed from this conference. The first concerns the compilation of data already published, and the second concerns the gathering of new data. We believe that the time is ripe for preparing a series of special studies, each dealing with the correlation and analysis of facts pertaining to one particular branch of petroleum engineering. For example, we should have exhaustive treatises on such subjects as gas-oil ratios, reservoir pressures, water encroachment, and so on. Much has already been published, but chiefly in scattered form [tnd with reference to individual fields. The importance of assembling geological and engineering data early in the development of an oil pool cannot be stressed too strongly. Many of our engineering recommendations and estimates are based on curves of changing factors. It is highly desirable that certain conditions and quantities be observed and recorded before they are seriously modified

by withdrawal of oil or gas. As engineers, we should endeavor to demon­ Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021 strate the practical value of securing facilities and personnel for beginning the collection of such technical data as soon as possible after the opening of a new pool. We wish, further, to advocate cooperation among operators in assist­ ing in the task of collecting this technical information wherever it can be used for the benefit of all. Often there is no good reason for holding it confidential. If our understanding of production problems is to be increased, we must have general support. The petroleum engineer is in a somewhat difficult position. Some of his activities are concerned with mechanical or physical conditions which can be measured and observed, as for instance in drilling practice, methods of producing oil or gas, fire prevention, transportation of petroleum, and refining technology; whereas other activities are founded on uncertain geological conditions which can never be accurately evalu­ ated. Such are studies of the movement of fluids through deeply buried rock strata, the form and position of the water-oil contact, and other similar relations more or less dependent on the lithological and structural characteristics of the subsurface strata. In cases where discussion relates to data which are contingent upon these unmeasurable geological con­ ditions, no harm can be done by clearly explaining that figures are approximations or averages and that conclusions are subject to some error. In other words, it is safe to admit that the petroleum engineer is not infallible when he deals with geology. Assuming that he can deter­ mine just what is the lithological character of the pay zone in each of a group of wells, he cannot do more than make a scientific guess at what the lithological conditions are between these wells. Let us make plain such important limitations, but let it be understood that, in spite ofthese limitations and the resulting margin of probable error in early estimates, the reasoning, based on experience elsewhere, is sound. 294 THE EAST TEXAS OIL FIELD We believe that one of the most important contributions that can be made by petroleum engineers is education of the industry and the public to a conviction in the soundness, the fairness, and the economy of well managed unit operation. There is not the slightest doubt, in the mind of anyone who knows the simplest facts in the case, that an oil pool is a natural unit which can be properly drilled and developed only by scientific cooperation. It has no relation whatever to artificial property boundaries. That the present laws should permit and encour­ age theft of the other fellow's oil or gas, or should sanction the dissipation of gas .energy, or should facilitate the waste of oil or gas-these things are almost unthinkable, yet they are facts as long as the law, which classifies petroleum as something subject to the right of capture, governs our development programs. With all our accumulated evidence of the value of controlled pool operation and our experience with the disadvantages of indiscriminate drilling, we are still obstructed from truly efficient Downloaded from http://onepetro.org/TRANS/article-pdf/98/01/279/2178392/spe-932279-g.pdf by guest on 30 September 2021 methods by this antiquated law. The industry will have advanced a long way forward when the law has been superseded by one which permits no one to appropriate more oil produced on his property than the maxi­ mum amount of oil that can be estimated to have been present beneath that property in the undisturbed condition of the pool before its discovery. To us the saneness of unit operation, or, if you will, of controlled scientific development, calls for no challenge. It is our province to demonstrate as often and as clearly as possible how such scientific development of an oil pool will facilitate proper well spacing, drilling of straight holes, control of water encroachment, efficient utilization of gas energy, control of gas-oil ratios, saving of gas and oil, lowering of production costs, disposal of salt water, and repressuring in the later life of the pool, and above all how, in the accomplishment of these economies, it will bring about the fairest possible allotment of oil or gas, or the pro­ ceeds from this oil or gas, to each owner in proportion to the size, posi­ tion and productivity of his acreage in the pool. The first chapter in the history of the East Texas oil pool has been little short of pandemonium, but all the chagrin and distress will have been worth while provided a lesson has been learned which will lead to a better understanding of the problems of the industry and to concrete measures for equitable scientific and legal improvement.