CORE LABORATORIES.1NC. Petroleum Reservoir Engineering DALLAS. TEXAS. March 21, 1958

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1 CORE LABORATORIES.1NC. Petroleum Reservoir Engineering DALLAS. TEXAS March 21, 1958 REPLY TO P. o. BOX 36 MIDLAND, TEXAS Zapata Petroleum Corporation Box 2216 Midland, Texas Attention: Mr. A. T. Carleton Subject: Core Analysis Phillips State "B" No. 9 Well Maljamar Field Lea County, New Mexico Location: Sec. 19-T17S-R33E Gentlemen: Diamond coring equipment and water base mud were used to core the interval, 4055 to 4345 feet, in the Phillips State lib" No.9. Engineers of Core Laboratories, Inc. selected samples of recovered formation for analysis as directed by a representative of Zapata Petr oleum Corporation. These samples were quick-frozen to preserve fluid content and were transported to the Hobbs laboratory. Formation indicated on the accompanying Completion Cor egraph to have both maximum and 90 0 permeability values assigned was analyzed by whole-core procedures using long segments of full-diameter core and formation having only a single permeability value assigned was analyzed by conventional procedures using plugs of recovered formation. Included with the analysis re sults in this report is a special reduced- scale graphical pr esentation of the core analysis data plotted to the vertical scale of five inches equal one hundred feet which is for convenient correlation of core analysis data to various formation logging data. Grayburg formation from 4055 to 4211 feet is characterized by favorable residual fluid saturations and is considered to be capable of oil production from points where permeability equals or exceeds 0.1 millidarcy. Although exhibiting measurable permeability the sample analyzed at 4186 to 4187 feet is considered to be essentially nonproductive due to

2 Zapata Petroleum Corporation Phillips State "B" No.9 Well Page Two low porosity and has been excluded from further consideration. The average permeability of the 27 productive feet analyzed in this over-all 156-foot interval is 8.9 millidarcys and the total observed natural productive capacity is 239 millidarcy-feet, indicating that economic rates of flow will be dependent upon su cc e s sful re sponse to formation treatment. The average measured porosity is 12.5 per cent and the average empirically calculated connate water saturation is 33 per cent of pore space. Recoverable oil estimates have been calculated for the Grayburg formation interval, 4055 to 4211 feet, using the observed core analysis data from the 27 productive feet in the interval in conjunction with estimated reservoir fluid characteristic s considered to be applicable to this ho r i- zon. These estimates are presented on page one of this report and are subject to the conditions set forth in the body of and in the footnotes to the summary page. From 4211 to 4231 feet, Grayburg formation is considered to be capable of oil production; however, the somewhat higher measured total water saturations in this zone indicate that a water cut is possible. The seven feet analyzed in this interval have an average permeability of 1.4 millidarcys and a total observed natural productive capacity of 9.5 millidarcyfeet, inadequate to support sustained satisfactory flow rates prior to favorable re sponse to treatment. The average porosity of this zone is per cent and the average calculated connate wate r saturation is 55 per cent of pore space. Estimates of recoverable oil have been calculated for the Grayburg formation interval, 4211 to 4231 feet, using the observed core analysis data from the seven feet analyzed in the zone in conjunction with estimated reservoir fluid characteristic s conside red applicable. These estimate s are presented on page one of this report and, in view of the possible water cuts to accompany production from this zone, your attention is respectfully directed to the conditions set forth in the body of and in the footnotes to the summary page.

3 Zapata Petroleum Corporation Phillips State lib" No. 9 Well Page Three San Andres formation analyzed from 4247 to 4325 feet is characterized at permeable points of analysis by residual fluid saturations which are considered to be favorable to oil production. Due to the low permeability of this zone and the limited number of permeable feet, however, the commercial value of the zone is limited and the advisability of attempting a completion attempt in the interval does not appear to be warranted. We sincerely appreciate this opportunity to be of service and trust that this this report will be of as sistanc e in making a preliminary evaluation of the Grayburg and San Andres formations analyzed from the Phillips State "B" No.9. RSB:JDJ:ds 22 ce. - Addressee 3 cc. - Mr. Tom Curlee Phillips Petroleum Company Midland, Texas Very truly yours, Rj73 a '/olr.rri,../'e... s(.,..,..,.i.. n,l..c_.'7r_ R. S. Bynum, Jr., Distric t Manager

4 TIIC:-iC uuul npininu or are scd observations whom. for whose coufideut se../1111 l ll B CORE LABORATORIES, INC. Petroleum Reservoir Enqineerino DALLAS. TEXAS Page 1 of 1 File WP Fe & we Well Phillips State "B" No. 9 CORE SUMMARY AND CALCULATED RECOVERABLE OIL FORMATION NAME AND DEPTH INTERVAL: Grayburg FEET OF CORE RECOVERED FROM ABOVE INTERVAL AVERAGE TOTAL WATER SATURATION: 34.0 FEET OF CORE INCLUDED IN AVERAGES 27.0 AVERAGE CONNATE WATER SATURATION: (c) 33 AVERAGE PERMEABILITY: MILL I DARCYS 8.9 OIL GRAVITY: API (e) 36 PRODUCTIVE CAPACITY: MILLIDARCY-FEET 239 ORIGINAL SOLUTION GAS-OIL RATIO: CUBIC F"EET PER BARREL (e) 500 AVERAGE POROSITY: PER CENT ORIGINAL FORMATION VOLUME FACTOR: BARRELS 12.5 SATURATED OIL PER BARREL STOCK-TANK OIL (e) AVERAGE RESIDUAL OIL SATURATION: 19.3 CALCULATED ORIGINAL STOCK-TANK OIL IN PLACE: BARRELS PER ACRE-FOOT 520 Calculated maximum solution gas drive recovery is 137 barrels per acre-foot, assuming production could be continued until reservoir pressure declined to zero psig. Calculated maximum water drive recovery is 333 barrels per acre-foot,assuming full maintenance of original reservoir pressure, 100% areal and vertical coverage, and continuation of production to 100% water cut. (Please rel er 10 [ootnotes for [urtber dis cussion of recoi'ery estill/lites.) FORMATION NAME AND DEPTH INTERVAL: Grayburg FEET OF CORE RECOVERED FROM AVERAGE TO.TAL WATER SATURATION: ABOVE INTERVAL 55.6 F"EET OF CORE INCLUDED IN AVERAGES 7.0 AVERAGE CONNATE WATER SATURATION: (c) 55 AVERAGE PERMEABILITY: MILLIDARCYS 1.4 OIL GRAVITY: API (e) 36 PRODUCTIVE CAPACITY: MILLIDARCY-FEET 9.5 ORIGINAL SOLUTION GAS-OIL RATIO: CUBIC FEET PER BARREL (e) 500 AVERAGE POROSITY: PER CENT 12.6 ORIGINAL FORMATION VOLUME F'ACTOR: BARRELS SATURATED OIL PER BARREL STOCK-TANK OIL (e) AVERAGE RESIDUAL OIL SATURATION: 12.6 CALCULATED ORIGINAL STOCK-TANK OIL IN PLACE: BARRELS PER ACRE-F'OOT 352 Calculated maximum solution gas drive recovery is 91 barrels per acre-foot, assuming production could be continued until reservoir pressure declined to zero psig. Calculated maximum water drive recovery is 229 barrels per acre-foot.assuming full maintenance of original reservoir pressure, 100% areal and vertical coverage, and continuation of production to 100% water cut. (Please refer to [ootnotes fat' [urtber discussion of fewijery ejlillh1iej.) (c) Calculated (e) Estimated (m) Measured (*) Refer to attached letter. These recovery estimates represent theoretical maximum values for solution gas and u/ater driue. They assnme tbat prodnctlon is started tit origina! reservoir pressure; i.e., 110 account is taken of production to date or of prior drainage 10 other areas. The ellats of [actors teneling to reduce actual nltimate recovery, sucb as economic limits all oil production rates, gas.oil ratios, or u-ater-oil ratios, hnue not been taken into account, Neither baue factors been considered which may remit ;11 actu.tl recol'el'y i7lterljledirite betu/een JO!,,' tion /!,e/j and complete water drii.«recoveries, such as gas cap expansion, gl'dl'ity df(linage, or partial umt cr driue. Detailed predictions of ultimnte oil recovery to [peeifie abandonment conditions may be made ill all engineering study ill which consideration is giuen to overall reservoir cbnract eristics and economic factors. y ses, s illh'! juct ation s ha 011 and materials :-.upplicd by the client to illnl exclusive <:1I1(] iul u this repor-t is runde. The iuterjuct atious or opinions expressed represeur the best judameut uf Core Lab.uat ories. Lm-. (;'\(1 ert-nrs and omissions ex cepr ed )"; but Clue Luh.u-atories. l nc., alld its officer-s and employees assume no responsibility an.l rnak e no w arrau t y or reprvsuut atiou as to th e productivity proper oper-ation, HI' p"fljitahlt-'lil'~s of any oil. ~as or ether mineral welt or sand in conncctiun With which such I't'port i-, used or relicd upon. '

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