University of Texas Bulletin No. 2230: August 8, 1022 Notes on the Oil and Gas Fields of Webb and Zapata Counties TheUndergroundPositionof the Austin Formationin the San Antonio Oil Fields B"sr E. H. Sellards Bureau of Economic Geology and Technology Division of Economic Geology J. A. Udden, Director of the Bureau and Head! of the Division PUBLISHED BY THE UNIVERSITY OF TEXAS AUSTIN Publications of the University of Texas Publications Committee : Frederic Duncalp J.L.Henderson G. C. Buttb E.J. Mathews Killis Campbell H. J.Muller F.W. Graff A. E. Trombly Hal C. Weaver The University publishes bulletins four times a month, s© numbered that the first two digits of the number show the year of issue, the last two the position in the yearly series. (For example, No. 2201 is the first bulletin of the year 1922.) These comprise the official publications of the University, publications on humanistic and scientific subjects, bulletins prepared by the Bureau of Extension, by the Bureau of Economic Geology and Technology, and other bulletins of general educational interest. "With the exception of special numbers, any bulletin will be sent to a citizen of Texas free on request. All communications about University publications should be addressed to University Publications,University of Texas, Austin. University of Texas Bulletin No. 2230: August 8, 1922 Notes on the Oil and Gas Fields of Webb and Zapata Counties TheUndergroundPosition of the Austin Formation in the San Antonio Oil Fields BY E. H. Sellards Bureau of Economic Geology and Technology Division of Economic Geology .1. A. Udden, Director of the Bureau and Head' of the Division PUBLISHED BY THE UNIVERSITY FOUB TIMES A MONTH, AND ENTERED AS SECOND-CLASS MATTER AT THE POSTOFFICE AT AUSTIN, TEXAS, UNDER THE ACT OF AUGUST 24, 1912 The benefits of education and of useful knowledge, generally diffused through a community, are essential to the preservationof a free government. Sam Houston. Cultivated mind is the guardian genius of democracy. . . Itis the only dictator that freemen acknowledge and the only security that freemen desire. Mirabeau B. Lamar. Contents Notes on the Oil and GasFields of Webb and ZapataCounties Stratigraphic Geology 5 RegionalDip " " 6 TopographicFeatures 6 Location of the Oil and Gas Fields with Respect to Topographic Features........ 8 Charco-Redoiido Wells. ..: 8 Jennings Gas Field 9 The Mirando Pool. .. 9 The Riser Gas Field 10 Tire Schott Pool. 10 The Carolina-Texas Oil CompanyGas Wells 11 Well Records . 12 Well Logs in Webb County 13 Well Logs in Zapata County 24 The UndergroundPosition of the Austin Formation in the San Antonio Oil Fields Introduction .v. 30 General Structural Conditions in the San Antonio District. . 32 Contour Map on the Austin Formation 33 Structural Conditions as Indicated by Contouring on the AustinFormation. . 34 Relation of Producing Wells to Structure 37 Producing Formations 38 Well Records , 38 List of Illustrations Map of Webb and ZapataCounty Oil Fields 7 Map ShowingUndergroundPosition of Austin Formation.. 35 Notes on the Oil and Gas Fields of Webb and ZapataCounties E. H. Sellards At the present time oil or gas is beingobtained from several localities in Webb and Zapata counties. The localities include the Charco Redondo oil wells, Jennings gas pool, and Mirando oil poolin Zapata County, and the Reiser gas wells and Schott oil pool and the gas wells of the Carolina-Texas Oil Company in Webb County. Of these several localities, the Reiser field is the oldest as a commercial field, having been discovered in 1909, although previous to that time oil had been noted in shallow wells drilled for water at the Charco Redondo Ranch. The followingnotes on the producingfields of these two counties are based1 on a reconnaisance of about ten days made in April and May, 1922. Stratigraphic Geology At the March meeting of the American Association of Petroleum Geologists, Dr. A. C. Trowbridge read a paper on the Coastal Plains formations in Texas, adjacent to the Rio Grande, which it is understood, will be published. Not wishing to anticipate in any way the results given in this paper by Trowbridge, the geologyand stratigraphy of this area willbe referred to at this time only in a very general way. Immediately at Laredo and for a few miles to the east, the rocks exposedin the stream beds and rock cuts are chiefly sandstones, often glauconitic, probably representing the Cook Mountain formation. Next to the east and extending almost, if not quite, to Reiser, is a broad belt in which clays predominate^ although some oyster shell beds are included. These clays represent the Yegua formaton. About twenty-two miles east of Laredo (three miles west of Reiser) is found a belt of very sandy land which may possibly represent a remnant of the Manuscript submitted for publication August, 1922. Issued September, 1922. 6 University of Texas Bulletin Fayette, or a sandy horizon in the Yegua. At Reiser and in a clay pit nearby, are seen clays and oyster shall beds not unlike those of the Yegua. Next east of Reiser, near Agnilares, and extending thence north and south is a belt of country in which the land is in places sandy and in which there are occasional outcrops of a light-colored rock with a limited amount of sand. This rock, which in places is chiefly volcanic ash containingplant impressions, probably represents the Fayette formation. Next to the east is found a belt of clay land which widens in the northern part of Webb County and possibly represents theFrio formation. About thirty-five miles east of Laredo is a prominent escarpment beyond which the land is level and slopes gradually to the east. The formation capping this escarpment is the Reynosa, which consists of caliche filled gravel and in places of caliche rock. The age of this formation is either Pleistocene or Pliocene. In the face of the escarpment, underneath the Reynosa capping, there is found in places a coarse sandstone which maybe of Miocene age. It is thus seen that the formations found at the surface are chiefly those of the Eocene series, together with possibly limited Miocene exposures,and in the easternpart of these two counties, the Reynosa limestone andgravels. Adjacent to the stream beds, of course, are Pleistocene and recent terrace deposits. Regional Dip The regional dip in this area is to the east. To the north and northeast of this area, the strike of both Eocene and Cretaceous formations is northeast-southwest, the dip being southeast. In the central and southern parts of Webb and in Zapata counties, the strike of the Eocene formations is approximately northsouth, the dip being, as stated, to the east. The average rate of dip has not been determined. Topographic Features In traveling east from Laredo,it is to be noted that for several miles, after crossing Chacon Creek, the country is characterized Notes on Oil and GasFields of Webb andZapataCounties 1 8 University of Texas Bulletin by successive minor ridges which trend, in general, north-south.- These ridges have a rather abrupt west face and represent west facing escarpments, marking the outcropping edges of east dipping strata. In some instances the escarpments are held up by a hard stratum consisting chiefly of oyster shell rock. About eleven miles east of Laredo the land becomes more nearly level. Just east of Mirando City is the pronounced Eeynosa escarpment to which reference has alreadybeen made. Location of the Oil and Gas Fields with Respect to the Topographic Features The Charco-Redondo and Jennings fields are located in or near the bell of country referred to above as probably representing the Fayette formation. Each of these localities is some distance from the Reynosa escarpment, the Charco-Redondo locality being possibly seven miles, and the Jennings field probably not quite so far. The Reiser gas field is likewise seven or eight miles west of the Reynosa escarpment. On the other hand, the Mirando and Schott ,pools and the gas wells of the Carolina-Texas Company are located immediately at the foot of this escarpment.1 Charco-Redondo Wells The Charco-Redondo oil wells are located in the southeastern part of Zapata County. The wells, now producing, are shallow, varying from 135 to 160 feet in depth. The oil is from sands and sandy shales, slightly greenish in color, found associated, with, and usually underlying an oyster shell stratum, which serves as cap-rock. About twenty-one wells have been drilled, of which sixteen are now being pumped, the production being from one to three barrels per day per well. The oil sand at this locality dips to the east. Thus the westernmost of the wells obtain production at a depth of from 135 to 140 feet, while wells farther to the east on land of equal or lower elevation find the oil sand at from 150 to 160 feet. About one mile west of the oil wells there is a west facing gas wells more recently obtained by the Carolina-vTexas Company one is reported to be located on the escarpment. Notes on Oil and Gas Fields of Weob andZapata Counties 9 scarp held up by an oyster shell stratum. This oyster shell bed is probably the same as that associated with the oil sand, indicating the eastward dip in the formations. The producing sands at this locality are probably in the Fayette formation. The oil has a gravity of about 18.5 B, and is said to yield a good quality of lubricating oil. The Jennings Gas Field The Jennings Gas Field is located in the northeastern part of Zapata County, about seven miles from the east and nine miles from the north county line. This field was discovered in 1914 when a test well for water obtained gas. Ten or more wells have been drilled. Two of these, failing to obtain gas, were drilled to a greater depth and obtained fresh water at about 1900 feet. The yield in the gas wells is said to be, for each successful well,between ten and twelve million cubic feet initial. Surface exposures of the light colored slightly sandy rock with strata of volcanic ash provisionally referred to the Fayetto formation were observed four or five miles northwest of the Jennings Field. No exposures were seen immediately within the gas fields, but it is probable that the surface formation at this locality is Fayette. The gas horizon at this locality lies between 1200 and 1300 feet below the surface. It seems probable that the gashorizon is within the Yegua formation,although formation thicknesses at this locality are not fully determined. The Mirando Pool The Mirando Pool islocated in the northeastern part of Zapata County, about two miles from the east and three from the north county line. The discovery well in this field was completed* in the spring of 1921. Since that time drilling has been actively continued in this field. These wells are located at the foot of the Keynosa escarpment, and at a place where, as indicated on the sketch map, the escarpment bends abruptly to the east. The producing sands in this field lie at a depth approximating 1450 feet from the surface. The wells are about seven miles 10 University of Texas Bulletin north and five miles east of the Jennings gas pool. Since the regional dip is to the east, if the gas at Jennings is from the Yegua, it seems probable that the oil at Mirando Pool is likewise from this formation. , On this point, however, the evidence is at present inconclusive. The logs of the deep wells in and near this* pool indicate that sandstones are entered at about 1700 feet. The wells at the west edge of the Mirando Pool produce gas, while in the central part of the pool the wells yield oil with but little gas. The oil is from .21.5 B gravity, and is said to contain very little gasoline. The Reiser Gas Field The Reiser Gas Meld, in Webb County, is located on and near the Texas-Mexican Railway, twenty-five miles east of Laredo. About twelve gas wells have been obtained at this locality, the best of which arereported to have made twenty or twenty-five million cubic feet of gas per day. Formerly the gas from this field supplied Laredo, but is used at the present time only for local purposes. The chief gas horizon at Reister is found at a depth of from 650 to 800 feet. Probably the gas in this field is obtained from the Yegua formation, although, as in the case of the other fields in this area, the age of the producing horizon cannot be regarded as definitely determined. The Schott Pool The Schott Pool is located about thirty-five miles east of Laredo, and one and one-half miles south of Mirando City.. The discovery well in this field was completedDecember, 1921... This pool is located near the foot of the Reynosa escarpment. The country is somewhat rolling, and there are occasional hills remaining as outliers or remnants of the Reynosa formation. The producing horizon of the Schott Pool is found at a depth of from 1525 to 1550 feet. About three miles southwest of this pool are exposures which appear to represent the Fayette formation from which it seems probable that the wells of the Notes onOil and GasFields of Webb andZapata Counties 11 Schott Pool, like those of the Mirando Pool, start near the top of the Eocene. Production in the Schott Pool is being obtained from seventy-five to one hundred feet deeper than in the Mirando Pool, the surface elevation being essentially the same. "Whether or not production in the Schott Pool is from the same horizon as in the Mirando Pool is undetermined at this time. At Mirando City, some oil has been obtained at a depth of about 1630 feet. A well located about three-fourths of a mile northwest of the Schott Pool apparently passed1 the oil producing horizon at about 1635 feet. This well continuing to a greater depth encountered a thick body of slightly sandy, blue and pink somewhat calcareous shale which was penetrated to a depth of 2500 feet, where sandstones were encountered. In the Sehott Pool as in the Mirando Pool, gas is found in wells west of those producing oil, apparentlymarking the west margin of the pool. The producing sands as indicated by the wells dips to the east with possibly a structural nose. The oil of the/ Schott Pool appears to be very similar in character to that of the Mirando Pool. The well of the Kanoka Oil Company in the Schott Pool, after being cleaned, produced not less than 800 barrels per day. The Carolina-Texas Oil Company Gas Wells The Carolina-Texas Oil Company has a well from which gas has been obtained, located about seven miles east of north of Torrecillas. This well is at the foot of the Reynosa escarpment,, and at a place where a small stream enters from the highland!,, forming, a reentrant in the margin of the scarp. Some gas was obtained in this well at 1295 feet, but the principal gas horizon is reported at a depth of 2015 feet. The formation from which the gas is obtained is undetermined. This; well is about ten miles north and four miles east of the Schott Pool. A second Avell drilled at this locality obtained some gas at 1296 feet.1 ]Two additional wells drilled since this manuscript was submitted and located east of the first two wells are reported to have obtained gas. 12 University of Texas Bulletin Well Records A summary of representative wells in these two counties is given in the table which follows. In addition a number of logs are included indicating the drilling conditions in the several fields. Summary of Representative Wells in Webb and Zapata Counties Name of Well. Location. Depth. Remarks. arolina-Texas Oil Co.. Surv. 268, 7 miles N. N. E. of Torrecillas 2015 Gas show at-1270-1270. at 2015. Gas Sapata Oil and Gas Co. Charco Redondo 1735 Oil sand at 103-168. Gas show in sand at 932-9C5. Texas Company. Jennings Gas Field. Jennings No. i iy2.mi. N. W. of Ranch House - - - 2,1/2 mi. N. E. of Ranch House _—, Jennings No. 3 ¦ 3015 Fresh water at 1908. 1367? 12 M gas at 1265-1387. pressure 455 lbs. Rock Cuellor No. 1 iy2 mi. E. N. E. of Ranch House 1284? 9 M gas at 1229-1234. pressure 4CO lbs. Rock Keeton Synd. No. 2 Mirando Pool. Miranda Oil Co. No. 2_ Mirando Oil Co. No. 3. Mirando Oil Co. No. 4a Mirando Oil Co. No. 7- N. W. pt. of pool. Blk. 23 S. pt. of pool. Blk. 5— S. pt. of pool. Blk. &-. S. pt. of pool. Blk. 5— Central pt. of pool. Blk. 17 1467 1502, 1426 1458 Gas at 1445-1467. Show of oil at 1447-1452. Producer. Discovery Weil. Oil sand at 1433-1442. 1490 Oil sand 1470-1476. 100 bbls. Witherspoon Oil Co. No. 4 Witherspoon Oil Co. No. 1 Tenn-Zapata Oil Co. No. 1 N. pt. of pooh Blk. 18- Oentral.part of pool. 2000 1460 Sandroek 1735-2000. Reported producing. 80 bbls. S. W. pt. of pool. Blk. 16 1476 Gas well, sand 1443-1455. Zapata Red. & Ref. Co. Surv. 113. S. of pool- 1730 Reported dry. Producers Oil Company. B. & M. No. 5.(Completed by Brethwith & Allison) Reiser Gas Field. Near Reiser 2598 Water at about 1800 ft. Sands 200 ft. from surf. Gas reported at 2500 ft. Mineral water at 1500±. Gas in use for local supply Reiser No. 1 Reiser No. .4 1mi. E. of Reiser At ReiS3r 2240 685 Well Logs in Webb Comity The following logs of wells in Webb County are arranged alphabetically according to owners of the land on which the wells are located, and the company owning the well. Log of Albercas No. 1, Altbercas Oil Co., Survey 836, About Three Miles North Slightly West of the Mirando Pool Notes onOil and GasFields of Webb andZapataCounties 13 iummary o if::: (!. s in ¦pa- ou: ¦¦¦a— i Name of Well. Location. Depth Remarks. Kanoka Oil Co. No. 1. Schott Pool. N. Central pt. of pool. Blk. 6 1559 Oil sand at 1545-1559. Reportted making1 800 bbls. per day. Laurel Oil Co. No. 1— Gas well. Leaseholders Oil Co. No. 1 Schott Oil Co. No. 2.. W. pt. of pool. Blk. 9- W. pt, of pool. Blk. 10 Central pt. 'of pool. Blk. 11 E. part of pool. Blk. 12 West of pool. Sur. 462-- 1539 1599 Gas well. Sehott Oil Co. No. 3— Schott Oil Co. No. 1_ 1532 1588 1750 Gas- and oil at 1530-1532. . Oil at 1671-1688. Ends in red and blue shale and gumbo. South Plains Oil & Gas Co. N. W. of pool. Sur. 460 2500 Below 1600 chiefly red and blue shales. Laredo Oil Co.'No. 2— InMirando City 1635 Oil at about 1635. Depth inFeet. Thickness. From. To. Red sandy clay Blue clay and boulders Shale ' Gumbo Shale and, boulders... . Green shale and boulders Lime rock Hard sandy shale l ._ Blue and green gumbo and shale Hard gummy shale : _. : Shale and boulders . Water sand Gumbo . Gummy shale and boulders Shale and sand, oil showing-. Tested out but no> results : Hard shale . Packed sand . Shale and sand _ Hard sh^lc-.i Gumbo "1-. ! ~ Hard shale * Gumbo j Shale antii boulders — Hard sandy shale . o 42 79 132 142 163 246 250 281 410 506 613 671 710 42 79 132 142 163 246 250 281 410 508 613 671 710 778 42 37 53 10 21 83 A4 31 120 10' 5f 3! 6i 778 780 840 871 961 962 1,055 1,142 1,172 1,280 789 S4O 871 961 992 1,055 1,142 1,172 1,280 1,309 i: t 3: es 8' 3< 10! a 14 University of Texas Bulletin Log of Albercas No. 1, Albercas Oil Co., Survey 836, About Three Miles North Slightly West of the Mirando Pool—Continued Log- of Barusly Ho. 1. Carolina Texas Oil Co. Survey 268, About Tour Miles Northeast of Mirando City Depth in Feet. Thickness. From. To. Gumbo ¦ Hard and soft shale, blue and brown Shale and boulders ...- Packed sand : Hard shale Lime rock ( Hard shale, pyrites and boulders time rock : __. __1 „»„.....„_,.,,„_ _„,,,„„„„ 'Gumbo --. . Shale and boulders—. — Sard gttitibo „...-..;....-'...-.... - .- Hard shale ..... Gumbo- Hard shale and boulders Hard and soft sand! rock: Hard sand rock, showing gas. Tested, no results Soft sand Hard shale, total depth 1.3091 1,318! 1,445 1,489 1,491 1,505- 1,507 1,548 1,550 1,559 1,585 1,661 1,684 1,709- 1,720 1,318 1,445 1,489- 1,491 1,505 1,607 1,548 1,550 1,55-9 1,535 1,661 1,684 1,700! 1,720 1,727 D 127 44 2 14 2 41 Z 9 26 76 23 25 11 7 1,727 1,734 1,739' 1,734 1,739 1,797 7 5 58 BeganDecember 7, 1921; completedFebruary 11, 1922; set 8", ca ing at 1735'; 1ft. in rock. 8" casing leftt inhole and -derrick 1< tion of drillingdeeper. ,sing at 3ft stan< 743'; set ding wit ; G" cashinten- Depth inFeet. Thickness. From. To. Olay Bock Sand Rock - Shale Sand - — Shale and boulders Rock — - - Sandy shale Rock _,__ - Sand Rock Sandy shale Rock Sand Has rock-— l Sand Rock —, - Sandy shale ¦ Gumbo Sand — — — Sand and boulders Rock Sand boulders Rock Sandy shale Gumbo -_— — — Sand and boulders Pay : ; i3umbo Sand and boulders 0 22 48 56 m 72 77 103 ¦(Of: 141 142 160 162 :is):. ¦197 217 228 229 254 260 270 310 313 iMi 380 402 407 428 435! 440; 22 48 56: 59 ' 72 77 103 108 141 142 160 iea 195 19? 217 220 228 . 329 254 260 270 310 312 375 380 402 407 428 435 440 460 25 9a. I Si 2i 10 40 2 63 } I Log of Barusly No. 1 Carolina Texas Oil Co. Survey 268, About Four Miles Northeast of Mirando City— Continued Notes onOiland GasFieldsof Webb andZapataCounties 15 Depth Feet. Thick- ness. From. To. Rock Sandy shale and boulders Gumbo __. Water sand : ;___ Sand and boulders ___ Pink gumbo Sand and boulders Gas sand , Sand and boulders Pay sand- — : Sand and.boulders Gumbo Hard sand - : Sandy shale . Sand . Bock Sandy shale ,— — Rock --— . Water sand Sand GumbO Sand and boulders : Gumbo : Rock . — ... . . Pack sand . — : I — Gumbo Gumbo :-" ; ; 1 Sandy shale ;. ~ — — Gumbo : Sandy shale - >-- Pay Clay (?) No log- 1,322 to 1,401. This well deepened by Trussle, Brown & Hodges. ¦Sandy shale; __..__^ . Sand and shale ! . . ; Shale and boulders : Sand — - '— - Gumbo - - :~-" Shale and boulders - ; Gumbo _.—. — .-— :— _. .— — __ Sandy shale and boulders : Shale , .. — — _i— . — — —— {Jumbo . -i- — Sandy shale ; Hard shale _ — -.:— .— Shale — — Gumbo .: ; Hard sand ;_ : ; ;_____ 'Shale ->— -, — — 460 464 610 616 630 760 764 780 796 827 835 910 916 930 970 1,000 1,002 1,060 1,065 1,070 1,085 1,088 1,130 1,135 1,137 1,155 1,168 1,195 1,222 1,226 1,270 1,295 464 610 616 630 760 764 780 796 827 885 910 9ie 9SO 970 1,000 1,002 1,060 1,065 1,070 1,085 1,088 1,130 1,135 1,137 1,155 1,168 1,195 1,222 1,226 1,270 1,295 1,322 4 146 6 14 130 4 16 16 31 8 75 6 14 40 30 2 5855 15 3 42 52 18 13 27 27 v4 25 27 1,401 1,460 1,535 1,550 1,568 1,573 1,600 1,608 1,654 1,685 1,700 1,725 1,732 1,800 1,815 1,827 1,466 1,535 1,550 1,568 1,573 1,600 1,608 1,654 1,685 1,700 1,725 1,732 1,800 1,815 1,827 1,935 65 69 15 18 5 27 8 46 31 15 25 1 68 15 VA 108 Total depth, 2,015. Shale grades into sandy shale and1 apparentl; grained sandstone, whichis producing aboutl 8 Mcu. ft. gas. into a coarse 16 University of Texas Bulletin Log of Breckenridge No.1, South Plains Oil & Gas Co., Survey No. 460, Southeast Corner of Block 15, About One Mile Southwest of Mirando City Depth in Feet. Thickness. From. To. Surface clay . __ Yellow clay and boulders Red clay and shale Lime rock Hard shale and boulders Gumbo Lime rock , Hard green shale and boulders Shale . ._ Ohalk rock . Gfnmbo Shale Packed sand __ Hard lime rock _ Gumbo . Soft gummy shale Soap stone 1_ Soft shale Gumbo Shale and boulders Hard shale , Lime rock Shale and boulders Gumbo '. '.. Hard shale Sand rock Soft lime rock Shale and boulders __ Hard ilme rock Gumbo- ¦ Soft shale Sand rock Hard sandy shale Water sand ; '. Hard shale ! Sandy shale ; jfumbo Soft shale Gumbo : Hard sandy shale and boulders Lime rock Hard shale and streaks' of gumbo .—.— Sand rock . Sandy shale '. , Gumj>o Hard shale and boulders Sandy shale Gumbo 1 Soft shale Hard gummy shale — Shale and boulders Gumbo - : Soft sandy shale 1. Sand rock Sandy shale Gumbo Hard sandy shale Soft gummy shale Gumbo Soft sandy shale; set 8" pipe Shell rock . Sand 0 20 72; 120 122 240 261 272 349 400 422 428 451 471 474 487 620 623 670 680 710 771 772' " 815! 830; 882 8921 905! 940; 9511 95Sj 9931 997 1,040 1,060 1,135 1,155 1,160 1,212 1,219 1,282 1,280 1,327 1,331 1,348 1,393 1,426 1,441 1,444 1,460 1,470 1,488 1,498 1,502 1,506 1,509 1,347 1,556 1,579 1,595 1,603 1,604 20 72. 120 122 240 261 2.72 349' 400 422 428 451 471 474 487 620 623 670 680 710 771 772 815 880 882: 892 905! 940' 951' 958 993 987 1,040 1,060 1,135 1,155 1,160 1,212 1,219 1,282 1,286 1,387 1,331 1,348 1,398 1,420 1,441 1,444 1,460 1,470 1,488 1,498 1,502 1,506 1,609 1,547 1,556, 1,579 1,595 1,603 1,604 1,685 20 52 48 2 118 21 11 77 51 22 6 23 20 3 13 133 3 47 10 \ 30 61 1 43 15 52 10 13 35 11 7 35 4 43 20 75 20 5 52. 7 63 4 41 4 17 45 33 15 3 16, 10 18 10 44 3 38 9 23 16 81 31 Log of Breckenridge No. 1, South Plains Oil & Gas Co., Survey No. 460, Southeast Corner of Block 15, Southwest Of Mirando CityAbout One Mile — Continued Notes onOiland GasFieldsof Webb andZapataCounties 17 Depth inFeet. Thick- ness. From. To. Sandy shale; set liner and bailed .___ Shale . Gumbo i . Green shale Gumbo Packed sand Shale . ll_i__ii"2: Gumbo Hard blue shale Pink shale Green shale, soft and hard streaks Pink shale and lime streaks Blue gumbo Pink shale with streaks of gumbo Gyp. gumbo Hard pink shale Blue shale Gumbo Pink shale Gumbo Hard blue shale _ Blue gumbo Blue gumbo Lime rock Gyp. gumbo Blue shale Gumbo Blue shale j. ! Hard pink shale Gyp. gumbo1 Sand Sand and shale streaks Hard gummy shale Green shale and boulders . Blue shale soft and gummy Green shale Blue and pink shale Pink shale Soft lime rock Gumbo Hard shale and lime streaks Not recorded Sand, shale , Sand and shale streaks Dry sand, gas show. Hard sand and boulders gas show Hard shale and shells Gumbo Sand I Pink shale and boulders Hard shale and sand streaks Gumbo Hard pink gummy shale Pink and blue shale I_ZI~II"IIC Bock and pyrites I__IIII Blue slate shale Soft shale and sand streaks , Sulphur water sand Hard sand , * ll___l__ Soft shale and sand streaks I--lIIIII.iI Hard sand' Blue shale . '_ Shale and boulders """ 1,685 1,641 1,660 1,665 1,725 1,731 1,741 1,747 1,751 1,784 1,785 1,831 1,860 1,866 1,947 1,957 1,872 1,998 2,004 2,015 2,021 2,030 2,055 2,060 2,061 2,007 2,100 2,106 2,128 2,176 2,180 2,186 2,195 2,202, 2,240 2,800 2,SCO 2,405 2,475 2,476 2,480 2,500 2,527 2,540 2,542 "2,550 2,562 2,578 2,588 2,591 2,603 2,623 2,630 2,665 2,689 2,690 2,709 2,726 2,746 2,775 2,802 2,807 2,816 1,641 1,660 1,665 1,725 1,731 1,741 1,747 1,751 1,784 1,780 1,831 1,860 1,866 1,947 1,957 1,972 1,998 2,004 2,015 2,021 2,036 2,055 2,0(50 2,061 2,067 2,100 2,106 2,128 2,176 2,180; 2,]86 2,195 2,202 2,240 2,300 2,360 2,405 2,475 2,476 2,480 2,500 2,527 2,540 2,542 2,550 2,562 2,578 2,588 2,591 2,603 2,623 2,630 2,065 2,689 2,6)0 2,709 2,726' 2,746 2,775 2,802 2,807 2,816 2,859 0 10 5 60 6 10 64 331 46 29 6 81 10 15 26 6 11 0 15 19 16 S3 6 22 48 4 697 38 60 6a 45 70 14 20 27 13"> 8 12 16 10 3 12 20 35 24 1 19 17 20 29 27 59 43 18 University of Texas Bulletin Log of Breckenridge No. 1, South Plains Oil & Gas Co., Survey No. 460, Southeast Corner of Block 15, About One Mile Southwest of Mirando City— Continued Log of Folts No. 1, Santa Maria de los Angeles Survey, About One-half Miles East of Bruni, InEastern Part of Webb County Depth inFeet. Thickness. From. To. Hard sand gas showing- -. _ ' Hard sand _ " Hard, sand gas showing- _ — Hard sand-——. Snlphud water sand Shale and1 'boulders , Shale and gumbo , — — 2,859 2,879 2,885 2,900 3,928 2,940 2,980 2,879 2,885 2,900 2,928 2,940 2,980 8,009 li 41 2! Depth in Feet. Thickness. Prom. To. Soil -__. - Sand and clay Sand and clay— , Hard sand Lime rock . Gravel and water sand Sandy shale Water sand Hard shale Gumbo Blue shale Water sand Blue shale Gummy red shale , Blue shale Gummy red shale Black shale Hard blue shale Gumbo ' Hard sandy shale Soft blue shale Gas sand Hard black shale Sea shell '. Sandy shale Sea shell _ Soft sandy shale 05 10 50 75 105 115 175 225 325 400 525 625 800 1,000 1,100 1,200 1,300 1,400 1,475 1,500 1,600 1,625 1,700 1,705 1,790 1,800 5 10 50 75 109 115 175 225 325 400 525 625 800 1,000 1,100 1,200 1,300 1,400 1,475 1,500 1,600 1,625 1,700 1,705 1,790 1,800 1,810 5 5 40 25 30 10 60 50 100 75 125 100 175 200 100 100 100 100 75 25 100 25 75 5 85 . 10 10 Casing set at 1,875 in cement; 4%" lines set at 1,650. Hole was bailed dry, making- quite a bit of gas; pulled lin< I,Blo', with no> oil showing. ss and inished ole at Notes on Oiland Gas Fields of Webb andZapaiaCounties 19 Log of Kanoka No. 1, Survey 54, About One and One-half Miles South of Mirando City. After Cleaning- Well Produced 800 bbls. or More. Discovery Well of the Schott Pool Depth in Feet. Thickness. From. To. Surface soil Yellow clay Soft lime clay— Loose gray shale Red and blue shale— . Water sand ___- Fine blue sand ; — Red mixed shale Hard red clay Red mixed shale Soft lime clay . Red mixed shale Blue shale Gummy. shale - Red and1 blue shale ___: Hard gummy shale--! Gumbo< : Soft lime rock — Red and blue shale , . Hard lime rock Red and blue shale * Hard lime rock Hard blue shale and lime Hard gummy shale : Lime rock <. , , Red and blue shale Lime rock i Hard blue shale — _. Lime rock Bed and blue shale^ Lime rock i. Red and blue shale Lime rock | ¦ Red and blue shale Lime rock Red and blue shale ¦ Gumbo Lime rock Gumbo : Hard gummy shale Red and blue shale Lime rock , . Hard gummy shale-- Gumbo1 Red and blue shale ± Gumbo Lime rock . Gummy shale Lime rock Gumbo Red and blue shale , Gumbo Lime rock and shale Red and blue shale Lime rock Hard blue shale - Red and blue shale Lime rock-— Hard' blue shale . Lime rock Hard blue shale Lime rock (gas big) .. Hard blue shale Hardlime rock: (gray sand) set casing 1515' 05 18 42 74 110 116' 150 210 230 252 274 296 320 332 373 390 411 420 448 453 512 522 601 622 635 660 672 700 776 844 860 940 978 1,000 1,023 1,073 1,084 1,102 1,114 1,129 1,140 1,168 1,184 1,196 1,210 1,227 1,248 1,271 1,282 1,293 1,304 1,313 1,328 1,350 1,362 1,374 1,390 1,406 1,440 1,462 1,499 1,508 1,513 5 18 42 ; 74 110 116 150 210 230 252 274 290 320 332 373 390 411 420 448 453 512 522 601 622 635 660 672 700 776 844 860 940 978 1,000 1,023 1,073 1,034 1,102 1,114 1,129 1,140 1,162 1,184 1,180 1,210 1,32? 1,248 1,271 1,282 1,293 1,304 1,313 1,328 1,350 1,362 1,374 1,396 1,406 1,440 1,462 1,499 1,508 1,513 1,515 5 13 2i. 32 366 34 60 20 22 2222 24 1421 26 12 9 28 5 50 10 79 21 13 25 12 28 70 ea 10 80 88 22 23 50 11 IS 12 /15 11 22 22 la 20 11 2] '?:.! mii ii 9' 15 22 12 12 20 10 34 22. 37 Si 52 20 University of Texas Bulletin Log of Kanoka No. 1, Survey 54, Mirando City. About One and One-half Miles South of More. DiscoAveftreyr Cleaning Well Produced 800 bbls. or Well of the Schott Pool—Continued Log of Laredo Oil Co., Well No. 1, Survey 458, ih Mirando City Depthin Feet. Thickness. Prom. To. Lime rock Shells and shale 111-I"!!"!!"!!" Sand rock "III"" Shale and sand IIIIII"" Gumbo ""I Shells and shale ~~~JII~I^ZI7^ZII Hard lime rock IIIIIIII"!! Hard sand (heavy oil sand) "~"I""II"IIIII I " 1,515 1,517 1,522 1,523 1,533 1,537 1,543 1,545 1,517 1,522 1,523 1,533 1,537 1,543 1,545 1,559 251 10 c4 2 v Stopped in gumbo. Set easing- in cement. Set 66', 7". Depth in Feet. Thickness. Fiom. To. Surface White lime and sand .. ~12 IIIIIIIIIIII"' Gravel I-""I"I""IIIIIIIII Sand 'Clay 11.11111 Sand, clay and shell lIIIIII_IIIIIII_III Pink shale ' ;_ ~"~~IIII"~~~ Red clay II~IIIIII.IIIIII! 'Gray shale 11111111111111111111" Blue and gray shale V. 11111111111111111111 White lime rock !_!__ 'Gray shale "_I-_II"IIIIIIII"III Pink gumbo "-I~I""I"IIIIIII Blue shale "II"! Gray gumbo' I__I___IIIIII Brown shale lI"_II Blue shale lI___III Gray shale _I_IIIZI"_~~III Sandy shale Hard shale Gumbo . Shale Sandy shale Blue gumbo___ Brown shale Gumbo Brown gumbo Blue gumbo Gray gumbo ; Blue shale Blue gumbo Sandy shale : ¦. Rock ! i Blue shale -. Brown shale '—-'- Shale and sand__ . Gray shale Gumbo Blue shale Lime rock Blue shale Gray gumbO 0 10 18 20 35 45 61 62 76 86 90 101 115 133 148 179 184 194 205 213 231 246 259 28:1 294 304 ::;:«> 344 "(>(> 375 S35 393 4IS 414 434 454 460 480 510 525 ">:;;; 555 10 18 20 35 45 61 62 76 86 96 101 115 :i:b I'4B 179 184 194 205 813 ;2m3g1 250 284 294 304 330 344 360 E75 3sn 393 413 414 4:;4 454 460 480 5.10 525 5.'53 555 587 1082 15 "10 16 1 14 10 10 5 14 18 15 31 5 10 11 8 18 15 10 28 10 10 28 14 16 15 10 8 20 1 20 20 6 20 BO 15 8 22 32 Log of Laredo Oil Co., Well No.1, Survey 458, in Mirando City— Continued Notes on Oil and GasFields of Well andZapaiaCounties 2.1 Depth inFeet. Thickness. From. To. 'Slate with coal "Gumbo I" Rock '_ ~~~~ Blue shale I— _l_l_l Gray gumbo "__ Blue shale -11111111111 "Gumbo .—IIIIIIIIIIIIIII White lime rock 1111111111 Blue shale Brown shale lIII__ ¦Gray shale Rock '_'_'_ 111111111111 Gray shale , lI_IIII__II Brown shale Gray and blue shale 1111111 :Soft gumbo White lime rock ~ lIIIIIIIIIIIIHII Blue shale 1.111111 Lime rock * . "_ Blue shalej 1.111111111111 Gray shale , 11.11111 "Gumbo 111111111 Lime rock Blue shale1 ¦__ ¦ 11111 Blue gumbo 1.111111111111 Light gray shale _ lll__ Blue gumbo t 11111 Shale : 111 Lime rock II" Blue shale Gumbo I Gray shale "II Shale and gumbo 1111111.1111111 Gumbo _ _ _ Shale lI— IIIIIIIIII Gray shale Lime rock Gumbo I 1111111111 Soft lime rock : 111111111111 Gumbo I I?IIIIIII_III Blue shale : 1111111111 Gumbo Shale . 1111111111111 Gumbo Shale and gumbo II Gumbo j Blue shale Gumbo : ' i. Shale I lIIIIIIIIIIZIIIII Gumbo ¦ Shale 1111 Gumbo Shale '_ Hard rock ;_i Sand (oil sand) Rock 587 615 654 656 664 715 759 760 778 800 816 824 825 875 883 909 920 952 960 972 978 1,014 1,029 1,039 1,049 1,059 1,076 1,084 1,089 1,092 1,114 1,146 1,165 1,185 1,215 1,230 1,260 1,275 1,285 1,291 1,321 1,341 1,411 1,431 1,446 1,466 1,496 1,521 1,531 1,561 1,581 1,621 1,636 1,650 1,654 1,662 615 654 656 664 715 759 760 778 800 816 824 825 875 883 905 920 952 960 972 978 1,014 1,029 1,039 1,049 1,059 1,076 1,034 1,089 1,092 1,114 1,146 1,165 1,185 1,215 1,230 1,260 1,275 1,285 1,291 1,321 1,341 1,411 1,431 1,446 1,466 1,496 1,521 1,531 1,561 1,581 1,621 1,636 1,650 1,654 1,662 28 39 2 8 51 44 1 18 2-2 16 8 1 50 8 22 15 32 8 12 6 36 15 10 10 10 17 85 3 22 32 19 20 30 15 30 15 10 6 30 20 70 20 15 20 30 25 10 30 20 40 15 14 4 8 This well gave a flow of oil when first drilled, of water trouble. Subsequently abandoned on iccount 22 University of Texas Bulletin Log of Well On Reiser Ranch, Producers Oil Co.,B. & M. Lease Well No. 5, Survey 1617, About One-fourth Mile South of Reiser's Station. Total Depth 2,598 Depth inFeet. Thickness. Prom. To. Surface sand Sandy red clay Brown sand Gravel with some salty water___ , Brown shale . Sandy yellow clay Brown shale -- Sand J. ¦- Shale - Shale - — Gumbo Shale - — Lime shells with some sand Red clay _„ Sand salt water Shale black Sand Sandy shale Gumbo Shale black Sand Shale Gumbo - Brown shale Sand, gas show Black shale Gumbo Red clay Sand Shale with sand shell Sandy shale . Gray salt sand Brown shale Sand Shale with sand Sandy shale Blue- shale, sand shells, iron . Gumbo Sand Sandy bluo shale Sand Black shale Sand Water sand Sandy shale Sand, water Shale Sandi Sand, set 8" 0 36 12 14 45 58 110 118 126 164 170 208 220 286 282 334 339 404 413 476 482; 564 570 642 649 &Ti 689 793 798 885 914 926 938 945 987 1,032 1,116 1,123 1,138 1,184 1,192 1,208 1,227 1,248 1,285 1,312 1,324 1,332 30 12 14 45 58 110 118 126 164 170 208 220 286 292 334 339 404 413 476 4821 564 570 642 649 674 686 793 798 885 914 926 938 945i 987 1,032 1,116 1,123 1,138 1,184 1,192 1,203 1,227 1,243 1,285' 1,312 1,324 1,332 1,369 3362 31 13 52 88 35 6 38 12 66 6 42 5 60 9 636 82 6 72 7 25 12 107 5 87 29 12 12 42 45 84 7 15 46 8 16 19 21 37 27 12 8 37 This well is said to have been subsequently drilled to a depth of 2,51 as obtained at about1,8001 feet, and gas* is reported at about 2,500 i )8 feet. :eet. Water Notes on Oil and GasFields of Webb andZapataCounties 23 Log of Garcia No. 2, Schott Oil Co., Survey 54, About One and One-half Miles South, of Mirando City. Gas and Oil Well, Initial Production Oil Reported at 74 bbls. Depth !n Feet. ness. Prom. To. fellow sand Soft lime clay fellow clay Blue shale_ Red clay Soft.lime rock Hard blue shale : Lime rock Hard blue shale.__ . — Blue shale and sand 3umbo Blue shale ~ Red' and blue shale Blue shale and sand Soft lime rock Hard blue shale and sand : Lime roclc rough gumbo . Lime rock Gumbo> Lime rock : 3-umbo T . Lime rock 3umbO' Hard blue shale Lime rock Bed andi blue shale Soft lime rock Red and blue shale . Lime rock ' 3umbo Blue shale Lime rock . 3umbo Blue shale and sand I'ough gumbo 3oft rock Hard blue shale _. 3umbo Lime rock Red and blue shale 3umbo' Lime rock Hard blue shale . .. Lime rock 1 ¦. Hard blue shale Srumtoo Lime rock 3umbo Hard blue shale Lime rock 3umbo. Hard blue shale Lime rock Blue shale : Soft blue mud Soft lime rock Red and blue shale Soft lime rock Hard lime rock _' rough gumbo Hard lime rock ! Soft lime rock Hard lime rock —.- Hard blue rock, sandstone Porous gray sand rock 0 2 10 30 57 107 135 168 165 220 260 290 330 342 475 490 537 563 600 637 670 673 685 687 700 745 750 800 805 861 873 897 900 918 937 960 983 1,000 1,020 1,067 1,083. 1,100 1,115 1,160 1,387 1,193 1,213 1,237 1,275 1,297 1,317 1,350 1,357 1,384 1,400 1,410 1,427 1,449 1,467 1,482 1,500 1,510 1,515 1,523 1,527 1,530 2 10 SO 57 107 135 163 165 220 260 290 330 342 475 490 537 "563 600 637 670 673 685 687 700 745 750 800 805 861 873 897 900 918 937 960 983 1,000 1,020 1,067 1,083 1,100 1,115 1,160 1,187 1,193 1,213 1,237 1,275 1,297 1,317 1,350 1,357 1,384 1,400 1,410 1,427 1,449' 1,467 1,482 1,500 1,510 1,515 1,523 1,527 1,530 1,532 2 8 20 27 50 28 28 2' 55 40 .30 40 12 136 15 47 26 37 37 33 3: 12 2 13 45 5 50 5 56 12 24 3131 18 19 28 23 17 20 47 16 17 15 45 27 6 20 24 38 22 20 33 7 27 16 10 17 2i 18 15 18 10 584 32 24 University of Texas Bulletin Log of Urban No. 1, Rio Grande Oil & Gas Co., Survey 7; Ten or Twelve Miles North of Laredo Log Wells in Za pa taCounty Log of Hinnant No. 6, Mirando Oil Co., Survey 114, Block 5, Lot 1, Initial Production 150 bbls., Mirando Pool Depth inFeet. Thickness. From. To. Yellow clay _ _ White shale _ _ Blue shale ' Pink shale Sand Blue shale , Cave Blue shale ¦: Cave Blue shale Cave Blue shale Sand, showing of oil-— Blue shale Slate "Water sand Shale Sand , : Slate Sand Slate Sand i Water sand Slate ... Sand Slate ._ Sand Slate Sand Slate — Sand , Sand Waterl sand Brown shale , Sand Slate Sand, began underreamingi 1,130'— Bed rock . Sand — — Red rock ». Sand Broken formation, sand, slate, red rock Sand 0 18 30 60 80 90 260 265 290 295 360 see 545 553 683 800 881 960 1,000 1,006 1,058 1,075 1,093 1,103 1,122 1,140 1,145 1,210 1,220 1,255 1,263 1,320 1,340 1,365 1,369 1,400 1,404 1,450 1,455 1,470 1,472 1,515 1,580 18 30 60 80 90 260 265 290 295 360 365 545 553 633 800 881 S6O 1,000 1,006 1,058 1,075 1,093 1,103 1,122 1,140 1,145 1,210 1,220 1,255 1,263 1,320 1,340 1,365 1,369 1,400 1,404 1,450 1,455 1,470 1,472 1,515 1,580 1,600 18 12 SO 20 10 170 5 25 5 65 5 180 8 80 167 81 71) 40 6 52 17 18 10 19 IS 5 65 10 35 8 57 20 254 31 4 4C 5 15 2 43 65 20 Casing record: Set 12%", casing at 553'; 10" at 1,058. Depth inFeet. Thickness. From. To. )lay and gravel .1.. Jack sand 51ue shale lard shale I ; Shale and sand »hale : Soulders ,-- 0 98 100 140 150 170 360 98 100 140 150 170 360 371 93 2 40 10 20 190 11 Log of Hinnant No. 6, Mirando Oil Co., Survey 114, Block 5, Lot 1, Initial Production 1500 bbls. Mirando Pool— Continued Log of Hinnant No. 7, Mirando Oil Co., Survey 307, Block 17, Lot 4, CompletedNovember 26, 1921, Mirando Pool Notes onOiland Gas Fieldsof Webb andZapataCounties 25 Depth in Feet. ness. From. To. Shale ,__ — Gumbo1 Shalo Sandy shale Shale Boulders Shale Boulders Hard sandy shale Hard red gumbo - Hard shale Rock ghale Hard shale and boulders Green gumbo , Hard shale ; Green gumbo* Hard shale and boulders Blue shale Hard shale boulders Stiff blue gumbo—: Hard shale Shale and boulders Hard shale Green gumbo' : Pay shale and sand Gumbo ; Hard shale. ____ - Pay sand1 and) shal©- -— - Boulders 371 590 600 638 641 658 665 720 725 815 826 857 860 863 1,040 1,059 1,099 1,108 1,123 1,167 1,231 1,257 1,320 1,384 1,401 1,412 1,425 1,431 1,448 1,462 590 600 638 641 658 "665 720 725 815 826 857 860 863 1,040 1,059 1,099 1,108 1,123 1,167 1,231 1,257 1,320 1,384 1,401 1,412 1,425 1,431 1,448 1,462 1,467 21! ll a 3 177 19 40o 5: 9( i: 3 y 15 44 64 6i 6> 1' i: l; 1' IDepth inFeet. Thickness. From. To. Olay and gravel ¦_ Mixed shale Hard sandy shale ; Mixed shale Bard shale Hard shale and boulder Hard sand Sandy shale Hard sand andl boulder— — Rock . ; Hard shale Hard sand - Sandy shale ,_ Hard shale Green shale and boulder Hard shale Hard shala and boulder. — Gumbo Hard shale andl boulder. _ - Bumbo — — - Hard shale and! boulder -— Bumbo and boulder _ Hard shale and boulder . Hard shale 3umbo> . 0 12 48 66 182 220 273 275 348 362 360 385 387 501 545 567 587 704 710 760 778 840 869 906 950 12 48 69 182 220 273 275 348 362 366 385 387 501 545 567 587 704 771600 778 840 865 906 956 991 12 38 17 117 33 53- 2 73 14 3 20 2 114 44 22. 20 117 0. 50' 18 62 25 41 50' Ss> ¦2(J University of Texas Bulletin Log of Hinnant No. 7, Mirando Oil Co., Survey 307, Block 17, Lot 4, Completed November 26, 1921, Mirando Pool— Continued Log of Hinnant No. 3, Witherspoon Oil Co., Survey 115, Block 3, Mirando Pool Depth in Feet. Thickness. From. To. Hard shale and) boulder _ Hard shale and boulder ', Gumbo Hard shale and boulder Boulder Hard shale , Gumbo Hard shale and boulder Gumbo and boulder . Hard shale andl boulder Hard shale Gumbo j '_ Shale Gumbo Hard sand- Shale 9&1 1,030 1,034 1,040 1,071 1,081 1,165 1,180 1,252 1,290 1,362 1,392 1,403 1,446 1,470 1,476 1,030 1,034 1,040 1,071 1,081 1,165 1,180 1,252 1,290 1,362 1,392 1,403 1,440 1,470 1,476 1,490 39 4 6 31 10 84 15 72 38 72 30 11 43 84 6 14 Casing record: &' 1,398'; initial iroduction re:portei at 100 Is. Depth inFeet. Thickness. From. To. Red clay and gravel Soft shale , Shale and boulders ; , Loose shale Shale and boulders Gumbo ' Hard gumbo _ Shale and boulders Gumbo - — — Hard gumbo :_ Gumbo and gravel Hard gumbo Pink shale Gumbo .. Shale _ Hard gumbo Gumbo' — — Pink shale Hardsand and boulders Shale anl boulders - , Gumbo and shale _ Hard gumbo.—. Shale - - Hard sand and boulders " Hard gumbo—— — — Hard sand and boulders : Sandy shale__._ 1 — — Sand and! shale... . . ¦Gumbo I,- — ...__._. — .Shale ___ _: ._ ¦ Sand, good oil showing __________' . ________ Soft' shale __¦__ — _____ Hard sand, oil showing-.. — — — ~ Shale and:sand.__ _— — ._——__: — 0 60 186 336 520 620 645 655 710 720 760 810 840 900 930 940 980 995 1,050 1,070 1,100 1,150 1,200 1,220 1,260 1,320 1,350 1,360 1,364 1,368 1,375 1,390 1,435 1,440 60 186 336 520 620 645 655 710 720 760 810 840 800 920 940 980 995 1,050 1,070 1,100 1,150 1,200 1,220 1,260 1,320 1,350 1,360 1,364 1,368 1,378 1,390 1,435 1,440 1,490 60 128 150 184 100 25 10 55 10 40 50 SO 60 20 20 40 15 55 20 30 50 50 20 40 60 30 104 :47 ¦1 60 Reported producing 90 bbls. per day in April,1922. Log of Hinnant No. 4, Witherspoon Oil Co., Survey 307, Block 18, Mirando Pool; Well Abandoned Log of Slator No. 1, Producers Oil Co., Jose Borego Vosquez Grant, Within About a Mile of North County Line; Elevation 595 Noteson OilandGasFieldsof Webb andZapataCounties 27 Depth inFeet. Thickness. From. To. Red clay and gravel : Shale Shale andi boulders Gumbo Gumbo and particles of iron : Boulders and shale Gumbo - Shale and boulders - Sand rock Hard gumbo i. Hard sandy shale Sand and boulders Hard gumbo * Shale and boulders , Hard shale Boulders and gumbo* Shale and boulders Gumbo _ ._ Shale and sand upper pay Hard gumbo and sand - Soft shale and) sand Hard brown gumbo Hard gumbo Sand, Gumbo Bock Hard gumbo Sand . Gumbo . . : . Bock . . ' . Sandy shale » Not recorded . Hard sand rock .._.. _ 0 60 180 400 460 520 600 680 760 770 820 860 900 940 1,110 1,140 1,220 1,250 1,260 1,380 1,435 1,445 1,450 1,490 1,500 1,563 1,565 1,600 1,610 1,690 1,692 1,700 1,735 60 180 400 460 520 600 680 760 770 ' 820 860 900 1,191400 1,140 1,220 1,250 1,260 1,380 1,435 1,445 1,450 1,490 1,500 1,563 1,565 1,600 1,610 1,690 1,092 1,700 1,735 2,000 60 120 9.9.0 60 (it) 80 80 80 10 50 40 40 40 170 30 80 30 10 120 55 10 5 dO 10 63 2 35 10 8i) 28 35 Depth inFeet. Thickness. From. To. Soil — Shale — — Sandy shale . ! Black shale Gumbo . Sand - Shale .__ Gumbo Shale Sand . . Shale .— - - , Gumbo .': , ; . Shale with iron— .......__ Bock, white. , - , : — — Shale, black . , — ,'. Sand -_ Black shale . — ; Sand i. — Shale , — — -.—.— :-i Sulphur, water^ sand and shale - ; Blue shale — - —— Sand .. - — — —— — 0 45 65 84 208 221 2SO 345 399 507 513 691 720 814 820 1,104 1,106 1,116 1,119 1,291 1,400 1,419 45 65 84 208 221 230 845 595 507 512 691 720 814 820 1,104 1,106 1,116 1,119 1,291 1,400 1,419 1,424 45 20 11) ¦m 13 9 115 SO 112 5 179 29 94 6 281 2 10a 172 10!) 19 5 28 University of Texas Bulletin Log of Slator No. 1, Producers Oil Co., Jose Borego Vosquez Grant, Within About a Mile of North County Line; Elevation 596—Continued Log of Zapata Oil & Gas Co., in Charco Redondo Field, Southeast Part of Zapata County, Yellow Clay and Sand Depth in Feet. Thickness.. From. To. Shale Shale and sand Sand and iron Shale _. Rock and sand Shale _ _. Rock sand and iron (show gas 1,582-1,540) Sulphur water, sand Sand and iron _'_ Shale Flinty rock and! sand Shelly shale Sand and iron Shale Shells and pyrite '_ Shale ._ Lime rock , Shelly shale Lime shell Shelly shale Slate Shelly shale Shale and slate Shale, sandy : Sand Shale, sandy 1,424 1,443 1,460 1,493 1,503 1,508 1,527 1,557 1,563 1,580 1,588 1,612 1,649 1,747 1,759 1,791 1,895 1,902 1,920 1,925 1,964 1,984 2,030 2,107 2,194 2,195 1,443 1,460 1,493 1,503 1,508 1,527 1,551 1,563 1,580 1,588 1,612 1,649 1,747 1,759 1,791 1,895 1,902. 1,920 1,925 1,964 1,984 2,020 2,107 2,194 2,195 2,210 10 17 33 IDS' 19' 30< 6> 17 8- 24 8V 98- 12- 32 104r 18- 5 39 20' 36 87" 87 1 15". Depth inFeet. Thickness. 3TI-om. To. Yellow clay and sand . Light green clay i Blue and green shale ;__ Boulders and slate Blue clay and slate Oil sand Shells, fossil oysters _ _ Olay and shale _" Light blue clay : Shale and fossil shells Olay and dark shale Shells and shale Red clay . Olay, thin sand strata White clay Red clay __. Green shale . Hard green shale __ Shell and shale ..__ _ Shells and shales Sand and shale I Green and! blue shale ._ Gumbo a -- ----- : - Red and green shales ... Shells and shale - Tough gumbo _ Brown shale "_; Hard slaty shale— . _ Gumbo ._-— -. .. — _ . 0 18 70 78 83 168 169 HM 240 ¦';)¦;¦, "271 :"!;::; ;',()', 323 362 :m 390 -i:;;; 443 610 019 C4B 062 714 760 760 Wi 759 18 70 78 83 163 :i, "M 760 '„<;,'> V;;;:' 789 sbe 18 52 85 80 5' 1 25 46: 18 13 12 24' 16 39 19 9' 48 5. 167 o. 29' 14 52' 46 9 14 6 14 Log of Zapata Oil & Gas Co., in Charco Redondo Field, Southeast Part of Papata County, Yellow Clay and Sand— Continued Notes onOiland GasFields of Webb andZapataCounties 29 Depth Feet. Thickness . From. To. Hard shale find boulders Shale and soft slate Dull brown gumbo* Hard sand and shells Shale, shells and concretions Shale Sand and boulders, gas bubbles Blue shale Sand and shale, pyrite Shale _ '___ Light green clay Dark shale „„_, Gumbo Blue shale Sand and green shale _ 11111 Hard sandstone ' ___." 11..1111 Sand and shale 11111 Hard sandstone Shale) and gumbo 1111111111111111 Shale and sandstone lIII_. Gumbo Shale and shells 111 "111 Black shale and pyrite Olay "mi Hard dark shale Sand and shale ~~~ Hard sandstone ___L Shale HI Shale and gumbo '111111 1111 Hard rock Shale ami slate __ Shells 111111111111111 Soft white clay Shale and slato__ lI—IIIIIIIIIIII Black shale and shells '__'. Olay, with shells _ .111111111 Shell rock gypsum , 11111 Shale and shells 111111 Sand and shale 1 1.111111111111 Soft white clay Hard rock concretions Shale II Bock. Soft white clay .111111 Bocks . Shale and clay I lIIIHII Shale and shells I-111111 Olay and boulders ... White clay . Shales and clay Rock slaty 11.-111111111. Bocks, concretions and gypsum ± II Sandstone White clay boulders I lIIIHII Shells and concretions Sandstone slate Bock pyrite lIIIIIII'I Gumbo .- " Sandstone Shale and sand.., 1111111111 803 807 826 841 848 860 932 '965 992 S9B 1,037 J.043 1,009 1,0781 1,118 1,130 1,150 1,172 1,175 1,226 1,238 1,247 1,263 1,270 1,286 1,298 1,302 1,308 1,329 1,341 1,347 1,3621 1,368 1,385 1,397 1,426 1,448 1,462 1,479 1,497 1,501 1,506 1,508 1,519 1,524 1,531 1,560 1,583 1,609 1,619 1,640 1,646 1,-C5B 1,673 1,687 1,702 1,707 1,712 1,717 1,728 807 820 841 848 860 982 965 998 1,037 1,043 1,069 1,078 1,118 1,130 1,150 1,172 1,175 1,326 1,238 1,247 1,263 1,270 1,286 1,298 1,302 1,308 1,329 1,341 1,347 i,;.62 1,868 1,385 1,397 1,426 ¦ 1,448 1,462 1,479 1,497 1,501 1,50© 1,508 1,519 1,524 1,531 1,560 1,588 1,609 1,619 1,640 1,646 1,658 1,673 1,687 1,702 1,707 1,712 1,717 1,728 1,785 IS If 12 7-2 36 21 38 fc 2e cI 4C 15 2C 22 £ 51 15 li 1: 2 i: 17 12 29 22 If 17 La £ 11 9,1 II Z 1: l! 1 1; 11 1 30 University of Texas Bulletin The Underground Position of the Austin Formation in the San Antonio Oil Fields E.H. Sellards The Austin formation, or Austin chalk, underlies all of the1 oil fields of the San Antonio district, and is itself productive of oil in the Alta Vista and Mission fields and perhaps to a lesser extent elsewhere. It is a thick formation, varying from possibly three hundred and fifty to four hundred and fifty feet or more, consisting of a chalky, usually light colored or blue rock, and with the possible exception of the Eagleford,. which lies next below it, is the most readily indentifiable formation of the Upper Cretaceous series. For this reason it isperhaps the most serviceable of the Upper Cretaceous formations in deciphering structural conditions from well records.. It is true that the transition from the overlying Taylor to the- Austin is gradual, and that there is probably a lack of uniformity on the part of drillers in recognizing the top surface of the chalk. However, such inconsistencies as arise from this cause, although of importance in detailed mapping, probably do not materially affect the accuracy or records when used in mapping general or regional structures. The well records here used are those of the Bureau of Economic Geology of the University of Texas, and include many records contributed or made available by several oil companies and individuals. In Bexar County, the Austin is found at the surface in a belt of country extending through the county in a northeastsouthwest direction and passing near, but mostly north of San Antonio. At its northwest margin this belt of Austin exposures is marked by a more or less well defined west-facing escarpment. Beyond'this escarpment to the northwest, the Austinis wanting, and the formations at the surface, with the exception of the Eagleford, are of Lower Cretaceous age. On the other hand, to the southeast the Austin passes underneath later formations and is found,as stated,underlying the oil fields. UndergroundPosition of Austin Formation in Oil Fields 31 While the Austin passes below the surface to the southeast, the rate per mile at which it drops to a lower level is by no means uniform. On the contrary it is found from well records that while, in places, the formation drops very abruptly to a lower level, elsewhere it again rises towards the surface, resulting in alternately structurallyhigh and low areas. To the southeast of the Alta Vista and Somerset fields, the Austin evidently drops to a lower level very rapidly, although there may of course be as yet undetected interruptions or reversals in the dip. That the average rate of descent of the Austin is rapid, however, is demonstrated by the fact that the formation, unless greatly altered in character, was not reached in the Bichter well near Pleasanton, about twenty miles south of the Alta Vista,field althoughdrilling was continued to a depth of 4015 feet, or to a level of about 3665 feet below sea level. In the northwestern part of Atascosa County the Austin formation lies at a depth of 1700 or 1800 feet. The drop to the Eichter well, allowing for difference in elevation, amounts to not less than 2500 or 2600 feet in fifteen miles. The average rate of descent in the formation crossing Atascosa County in a southeasterly direction is therefore not less than an average of 165 or 175 feet per mile. In referring to the undergroundposition of the Austin chalk it is of course understood that this formation is but one of a series of formations lying in natural order, the one upon the other, and that where the records are such as to indicate that one of the formations lies at a relatively high elevation it may be with confidence concluded that the other formations of the same series, when not separated by an unconformity, likewise lie at a relatively high level at that locality. In this way a certain formation recognizablein well logs may be used in determining structural conditions, regardless of whether the formation itself is productive or not, and from structural conditions in turn may be inferred to some extent the probability of oil production in that particular locality. Accordingly the Austin, for the reasons given, is here used in depicting the structural conditions in this region so far as these conditions 32 University of Texas Bulletin can be shown on a small map and) from wells that are in some parts of the area much fewer in number than could have been desired. General Structural Conditions in the San Antonio District No more than brief reference will be made at this time to the general structural conditions in the San Antonio district, these conditions having been somewhat fully described elsewhere. The Balcones zone of folding and faulting, as is well known, passes through this district. The' inner margin of this fault zone (inner in the sense of farthest inland from the Gulf) is markedr in this part of the State by a pronounced southeast facing escarpment, the trend of the fault zone being northeast- southwest. Beyond the escarpment to the northwest the formations, which are those of the Lower Cretaceous, are but little disturbed by faulting and have a very moderate and scarcely perceptible dip towards the Gulf. To the southeast of this escarpment, on the other hand, is a region of profound disturbance, the formations being both faulted and folded. This disturbed zone is known to be more than twenty miles in width and! it may be much wider. The faults observed are normal or tension faults, the downthrow being in the direction of the dip of the fault plane. In most of the faults the downthrow is to the southeast. This, however, is not invariable as faults are seen at the surface and recognized in well drilling in which the downthrow is in the opposite direction or to the northwest. In that case the dip of the fault plane, where observed, is likewise to the northwest. The faults with downthrow to the southeast exceed in number, as already stated, those with downthrow to the northwest; they likewise in general exceed in intensity or in amount of throw. Moreover the regional dip is to the southeast and- while there are reversals of dip, these are seldom continued for any great distance. The ultimate result of faulting and folding in this zone is to carry the formations very rapidly to a lower level. "When averaged across the county from the Balcones Escarpment to the eastern part of Bexar County the rate of drop in the formations will UndergroundPosition of Austin Formation in Oil Fields 33 be found to fall between 100 and 150 feet per mile, probably a close approximation to 125 feet per mile. But that such, an average rate of descent can be applied only in the most general way, becomes apparent from an inspection of the map and records which follow. Contour Map on the Austin Formation On the accompanying map there is assembled the information now available on the underground position of the Austin formation in the San Antonio oil fields. The belt of surface outcropping of the Austin is indicated on this map by the shaded area. To the east of its outcropping area the position of the Austin is indicated so far as practicable from records now at hand, by contouring, the contours being in depth below sea level as indicated. Likewise the location of the wells used in contouring is indicated and the depth with respect to sea level, at which the Austin was found in that particular well, is entered on the map. In this connection it should be stated' that the surface elevation of the various wells has been taken largely from the topographic map,although for anumber of the wells not on the topographic maps the elevation has been determined approximately by barometer readings. There is necessarily a small possible error in elevation of wells, and this should be taken into consideration in using the map. The possible error from thissource, however, is probably less than the average error incident to recording and interpreting well logs, and is probably negligibleor nearly so in regional mapping. In 1920 a bulletin on the geology of Bexar County was issued by the Bureau of Economic Geology, in which structural conditions were indicated by contouring on the Del Rio, a Lower Cretaceous formation.1 A comparison of the map issued at that time, with the present map, shows that the major structural features recognized from the Del Rio formation, are like- %The Geology and Mineral Resources of Bexar County, by E. H.. Sellards, University of Texas, Bureau of Economic Geology and Technology, Bulletin 1932, March, 1920. 34 University of Texas Bulletin wise shown by contouring on the Austin formation. However, by the aid of wells drilled during the past two years, the mapping has now been extended into Atascosa and Medina counties. Accordingly the map now issued includes the greater part, but not all, of Bexar County, and a small part of Atascosa and Medina counties. In the southeastern part of Bexar County but little drilling has been done, and in this part of the county no progress in contouring the underground structure has been made. For this reason this part of the county is not included in the present map. In the map previously issued based on the Del Bio formation, faulting, so far as recognized from underground records, was indicated. The present map has been simplified to the extent of not attempting to indicate such apparent lines of faulting. It may be stated, however, that such new records as have been added since the first.map was published in so far as they relate to faulting support the interpretation previously given. Structural Conditions as Indicated by Contouring on the Austin Formation The outcropping belt of the Austin in Bexar and eastern Medina counties shows notable irregularities of outline not accounted for by erosion. Thus in the western part of Bexar County north of the Portranca public road there is a broad belt of the Austin which extends in a southwesterly direction into Medina County. This belt of Austin forms a ridge of much greater elevation than the plains at either side. The level and much lower land at the north and at the south is, for the most part, covered by terrace gravels, but such exposures as are seen indicate the Taylor formation. When followed to the southwest, the Austin formation is found to pass under later formations. Again immediately north of San Antonio there is found a similar, although much narrower belt of the Austin formation, extending into the northwestern part of the city, and forming the surface exposures seen in Brackenridge .and San Pedro parks. Surface exposures of the Austin, in UndergroundPosition of Austin Formation in Oil Fields 35 Fig. 1.— Map showing approximately the underground position of the Austin formation in Bexar and in the adjacent parts of Medina and Atascosa Counties. Shading indicates area where the Austin is at or near the surface. Contours on the Austin chalk. Contour interval 500 feet. Sea level datum. 36 University of Texas Bulletin this locality,are found at an elevation of 800 feet or more abovesea, while both to the north and to the south the top of the- Austin is encountered at a much lower level. It is thus apparent that these two belts of Austin exposures are due to^ structural conditions. In the case of the Austin exposures in- San Antonio, faults are observed which limit the exposures at the south, these faults giving rise to the San Pedro, San Antonio and Salado Springs. At the north side, the Austin is limited by faults with downthrow to the north or by abrupt northwest dips in the strata. In the case of the broad belt in the western part of the county, the structural conditions are produced either by step-faulting or by folding. In each instance the structural feature is a southwest plunging anticline or fault block. While these structural features are observable at the surfacein the central part of the county, they are more or less obscured south of the Austin belt by the non-resistant character of the formations together with the mantling surface materials. From examination of the well records, however, it becomes apparent that this type of structure, southwest plunging anticlines or fault blocks, is characteristic of the area as far south at least as the south line of Bexar County. Thus the fault block seen from surface exposures in the city of San Antonio may be followed by well records to the oil and gas wells west of Leon Creek, and possibly also as far as the Medina River. The GasRidge field, which has produced chiefly gas, and in addition a small amount of oil, is obviously accounted for by this structural feature. Another very pronounced structurally high area is that found at the Alta Vista oil field. At this locality the Austin formation lies about 300 feet below sea or within about 900 or 965 feet of the present surface (900 log; 965 samples). Immediately north of the Alta Vista field the Austin lies at a much lower level, the difference beingso great as to suggest the probability of faulting with downthrow to the north. The wells of the Alta Vista and Mission oil fields are located within this structurally high area.^ UndergroundPosition of Austin Formation in Oil Fields 37 Relation of Producing Wells to Structure. The principal groups of producing wells in this region are indicated on the map. These include the Somerset field, South Medina and Yturri wells, Alta Vista and Mission pools, and the Gas Ridge wells. It will be seen that these producing wells are associated with the structural features of this area. It is probable that production is controlled in some fields by faulting and in others by folding. In either case production is likely to come chiefly from the southeast slopeof the structurally Mgh feature. That is, the favorable location for a well is either on or somewhat east of the axis of the '' structure. '' This is probably due to the fact that" the structural features of this area are unsymmetrical, the northwest slope being short and hence affording but little collecting area for oil. The southeast slope, on the other hand, in which the strata are returning to their normal southeast dip, is likely to be long and thus to afford1 a considerable collecting ground for oil. With regard to the kind of faults that favor accumulation, it is to be remembered that there'are many faults of varying intensity making up what is known as the Balcones fault zone. Most of these faults have the downthrow to the southeast, that is in the direction of the regional dip. Such faults, with downthrow to the southeast, do not provide favorable conditions for the accumulation of oil, for the reason that they merely intensify the rate of dip or descent of the formations to the southeast. Some of the faults of this zone, however, have the downthrow to the northwest. In all of these faults, the fault plane dips towards the downthrow side. In the case of a fault with the downthrow to the northwest, it follows therefore, that the "d]rag" which is incidental to faulting amounts to or brings about a short abrupt dip of the formations in the direction of the downthrow, or in this instance to the northwest. These conditions, without doubt, explain the fact that it is the faults with downthrow to the northwest that bring about conditions favorable for production, the drag to the fault planeserving as reverse dip, aided possibly by deposition in the fault plane. 38 University of Texas Bulletin Producing Formations With regard to producing formations, more or less production, or oil showings, have,been obtained from all of the Upper Cretaceous formations in this area and possibly to some extent from the Midway, which overlies the Cretaceous. In the Somerset field the principal production is from about 500 feet above the top of the Austin chalk and! probably near the contact of the Taylor and Navarro formations. The Lower Cretaceous now known to produce oil in Limestone and Caldwell counties, is present, underlying the Upper Cretaceous. Well Records The wells used in recording the underground position of the Austin formation are listed in the following table. The "map entry," given in the table, appears also on the map and is intended to assist inlocating the well. It records also the elevation of the top surface of the Austin with respect to sea level as nearly as has been determined for that particular locality. Thus the entry 412 records the top of the Austin as 412 feet above sea level. Entries precededby the minus sign, as — 1700, record depth of the Austin below sea level. In addition to the logs used in mapping a few have been added in Bexar, Medina, and Ataseosa counties, which are beyond the area covered by the map. Bexar County Name of Well. Location. Elevation. Total Depth. Top of Austin-. Map entry. Allen, D. J Applewhite _. ' Arrowhead Oil Oo._- Basse, E. E Benke, Mrs. X Blue Wing Club Brendle, H. Breckenridge Well _._ Brown, Marathon Oil Co LLcl. Oassin '"_. 1 Clamp, C. CCollins Gardens Carney, Glen Elder and Wolf Kelly Field? 16 mi. S 2% mi. W., 1 mi. N. Somerset 5 mi. N. San Antonio '22 mi. N. W -12 mi. S 527 Banders St., S. A Near Salado Creek €80 500 650± 760T 1.030T1 490T 720 630 1,054 1,952 1,700 590 1,000 8,444 coo 1,89ft 1,5~0 300 1,746 180 70± 80 —1,396 —920 735- 730: —1,256 mo- 1,018 560. 2 mi. due E. Somerset. _„_ 9 mi. S. S. A & mi. west S. W. Pt, S. A 7% mi. E. of San (Antonio 8%! mi. S. S. A. (Alta Vista) 625± 550 700 650 650 1,463 1,452 1,519 873.? 525 530± ——894"- 42S 38 125 1,226 120-* 600 1,288. 900± —3005 UndergroundPosition of Austin Formationin Oil Fields 39 Bexar County— Continued Name of Well Location. Elevation . Total Depth. Top of Austin. Map entry. Frederick Well 'Guentther MillingCo. 'Government Well, Aviation Post Government Well _-- .Ty2 mi. S. W. San Antonio . 902 Morales St., S. A 655 675 1,200 740 250± —85 425 .0 mi. N. E .Hackberry St., near Aye. O .4.5 mi. W ..7.5 mi. S N. of Kelly Field 1 .9 mi. S. W .4.5 mi. S 735T .874 55± 680 Herf, H. Hill and Roby Hofheintz, R. H Holtz Hot Wells Kearney Oil and Pipe Line Co. Kreutcli, O. Kui'z __ Legler, W. F Linn 2 Lone Star Brewing LaOmom..«1, Ulf-Vanies Exploration Co. __ Masterson 1, Meecham Oil Co -Melntosh, Mrs. Mathey 1, Bexar Petroleum Co. Medina Oil Co M. K. T. Ry Perrinot Well, Schlathei- Ind. Porch Well ess t'B2 625 680 610 575 I 729; 1,266 1,890 1,453 1,665 1,878 258 621 1,200 coo 1,200± 900 431 62 —575 80 —575 —415 . 12 mi. S. of S. A I . 5.5 mi. E. S. A._ I 1mi. S. E. of Somerset-,I .5mi. W. I . is mi. S 610 I 675 638 695 550 j 2,355 1,000 1,650 1,555 1,443. 420± 1,450 670 1,084 347 — 255 812 25 —544 [ 120 ,Jones Avc ' 660 805 248 412 [ 16 mi. S 500 2,693 ¦ 2,200± —1,700 18 mi. W . 7 mi. E. of S. A 750 700 3,2:45 668 255' So± 495 670 1mi. W. Losoya 12 mi. S. Landa _¦_ 515 ' 530 i 784 2,332 1,833 643 1,892 1,012 60± —1,377 —482 724 2 mi. S. W. Martinex ny2 mi. s 6SOT 530T 1,375 1,505 1,239 Not —55!) Ridder, A. J S. A. & A. P. Ry.- San Antonio City Water San Antonio City Water San Antonio Portland Cement Oo.__ 'Schmidt, Marathon Oil Co. Sbatuck Well Smith, Sarach 13 mi. S. W Probaa and Simpson Sts: 628 I 630 j 2,911 1,103 reached 9oo± 500 —975+ —272 130 Market St. 650 880 220 430 Conception Mission 605 1,440 780 175 5 mi. N 740 C67 60 680 1% mi. due E. Somerset.- 19th St. W 2 mi. E. S. K. of Somerset 635± . 678 650± 1,668 1,579 335 —944 343 Not Southern Ice Co Southwest Land Corporation Somerset Well Prio and Durango Sts 655 822 reached 260 —I,olB+ 395 4 mi. W. Somerset, cored by Kerr at 1600. Austin 1,560-1,950- W. 5.4 Steves Garden 509 King- Williams St 8.5 mi. S. of S. A 3% mi. S. E. of S. A 7 mi. E. of S. A 5.2 mi. S. of S. A S. W. city limits, S. A... 708 I 1,000 390 318 "St. Louis College 'Steves, Mrs. J 'Steves, Mrs. J Steves, Ed. "Sullivan, D. Taft, L. S Terrell Hot Well Terrell, J. H Texas Steam Laundry.., Tommins, R. __ Union Meat Co I 650 7CO 645 645 660 620 665 630 675 2,320 702 1,185 758 1,840 1,100 1,240 1,950 1,140 1,560 215 60* 250 1,300± 505d: 880 1,000 550 —910 545 41 — 399 640± 115 215 —370 125 205 L-osoya St South city limits, S. A._- Laredo and Ralph Sts., S. A. ... _- 14 mi. S. W. of S. A.— 665 630 748 1,500 290 i 900 375 —270 Voght, Wm — Walsh, Meechum Oil Co Waring Well Yt.uiTi 1, W. H. Reynolds et al 640 605 1,400 1,850 340 985± 300 380 13 mi. S. of S. A 7.5 mi. N. W. of S. A.- 550 920 1,736 2,853 1,403 13 — 853 907 9y2 mi. S. San Antonio— 1 510±! 3,460 1,476? 966? 40 University of Texas Bulletin Medina County Atascosa County Name of Well. Location. Eleva- ; Total Top of lion, i Depth. Austin. Map entry. Blackaller 1, Mid- Frio Oil Oo I 5 mi. E. and 3 mi. N. of the S. W. corner of county 800T 3,115 1,960 745 1,648 1,550 1,000 | 1,000 975 670 2,540 2,287 : 1,233 740 I W. Garnand, Somerset, Western Oil 00. Gray Well _. Thomas Surv. 516 Abt. 1 mi. S. E\, Lytle 8 mi., 113^ Th. Thomas 4y2 mi. S. W. of Dunlay.- —1,160? —805 Haas, Geo. _ Kimble, Osman Oil Oo 125 McOlure, T. S., 1— Near Devine, 2 mi. S. W. S. Reiden, John No. 28 3 mi. S. W. Dunlay Sta. on S. P. Ry. See T. S. McOlure, 142 Goliad St. — 1,61T Eleva- | Total tion. | Depth. Top of Austin. Map Name of Well. Location. entry. Cnruthers 11, Grayburg Oil Co About 2 mi. S. W. Somerset I 2,378 1,775 . ChildressNo. 1, Leming Oil & Gas 00. Now owned byHollingsworth, Pleasan'on Poster, Grayburg: Oil Oo 1mi. S. of Lemirig 450 A 2,600 745A Not —2,150+ Somerset Oil Field 5% mi. W. S. W. Somerset Survey 523 reached! Fowler, Gulf Production 00. Fowler Lease No. 2 1,863T' —1,118 Somerset Oil Field 2. mi. S. W. Somerset j 1,829 1,825 I ---1,175 Hartung-Lease1. W. 1. GrayburgOil 00. Survey 140, 3 mi. ± S. W. Somerset 1,919 1,968 !—1,318 Hartung 17, Grayburg Oil Oo 4% mi. S. W. Somerset' Surv. 385, J. J. Knott— 2,290 — 1,,640 McCain Lease 1. W. 2. Grayburg Oil Oo 2,729> I Survey 1,970, S. W. ofj Somerset i I i : 1,973 —1,323". Muenniek Well 2. Grayburg Oil Co.-- Richter 1, Galvan Oil Oo 'Atascosa County | 1,975 1 1,908 1,903 —1,253: iy2 mi. N. E., Pleasanton, E. H.,, Timmons Surv., N. W. part Sot reached' —3,6654- SoOAI; 4,015