Project Gasbuggy a Nuclear Fracturing Experiment

Project Gasbuggy—A Nuclear Fracturing Experiment

D. C. WARD U. S. BUREAU OF MINES Downloaded from http://onepetro.org/JPT/article-pdf/18/02/139/2224539/spe-1273-pa.pdf/1 by guest on 27 September 2021 C. H. ATKINSON BARTIESWUE,OKLA. J. W. WATKINS WASHINGTON, D. C. MEMBERS AIME

Abstract Engineers at the Bureau of Mines’ Bartlesville Petro- leum Research Center early in 1959 began to investigate Project Gasbuggy was insdtnted to design, conduct and the potential for nuclear-explosive (NE) stimulation, The evaluate a nuclear fracturing experiment and it is a joint initial work was carried out on a limited scale with engi- undertaking by the Untted States Atomic Energy Com- neers of Continental Oil Co. Since 1962 tbk work has mission; Bureau of Mines, U. S. Dept. of the Interior; been performed on an expanded scale under a coopera- the U. of California Lawrence Radiation Laboratory at tive agreement with the San Francisco operations office, t Livermore; and El Paso Natural Gas Co. The experiment Special Projects Div. (Plowshare), Atomic Energy Com- is designed for the detonation of a 10-kiloton fission ex- mission (AEC}. The Plowshare program was established plosive at a depth of 4,150 ft to evaluate the stimulative to develop peaeef ul uses for nuclear explosives. This effect on gas production from the Pictured Clifis forma- cooperative research has resulted in the following conclu- tion in the Sari Juan Basin, N. M. sions: (1) the application of NE in stimulating production from selected low-productivity oil and natural gas reser- Nuclear-expiosive stimulation of natural gas reservoirs voirs is technically feasible: (2) the extensive, thick, Iow- is technically feasible; but only from arwlysis of produc- permeability natural gas reservoirs in the Rocky Mountain tion data obtained by this and future’ experiments can the region appear the most favorable for application of, NE economics be determined. Favorable results from Project stimulation,’ (3) the economics of NE stimulation can be Gasbuggy could pave the way for substantially increased recovery from many known but low-productivity hydro- determined only by a full-scale field test, and (4) justifi- cation for such a test lies in the number, areal extent and carbon reservoirs. resources of Iow-productivit y gas reservoirs where producing ratgs and ultimate recovery may be substantially Introduction increased.

For more than a century, petroleum has been produced A survey of gas fields and discussions with operators re- commercially in the U. S., and present-day estimates are sulted in a choice of several Ioeations where field tests that produced hydro-carbons supply approximately three- should be feasible. One of the most promising of these fomths of the total energy consumed in this country. An prospective test sites is on El Paso Natural Gas Co.’s ever-increasing demand for petroleum, coupled with in- (13PNG) acreage in the San Juan Basin, Rio Arriba Coun- creasing difficulty and cost involved in finding new petro- ty, N. M. An affkmative preliminary evaluation of the leum reserves, has placed emphasis on increased recovery ‘ suitability of this site and the desire of EPNG to partici- from known hydroearbon-bearing reservoirs, The inability pate in such an experiment led to the initiation of Project to reeover more than a small fraction from some of these C3asbuggy. Nuclear detonations under the AEC .Plowshare known deposits by existing technology and eeonomies lim- program are customarily named for vehicles. its development of our natural resources: Proj~t Chisbuggy was instituted to. dmign, conduct and In 1957, a. 1,7-kt (a kiloton is the energy equiva- evaluate a NE stimulation experiment in the Pictured lent of 1,000 tons of TNT) nuclear explosive was deto- Cliffs reservoir at the proposed Ioeation and is a joint un- nated at a deuth of 899 ft below the Rainier mesa at the dertrtking by the. AEC, EPNCi, USBM and the U. of .,, . Nevada test ate near Mercury, Nev. The Rainier test, California Lawrence Radiation Laboratory at Wermoce, which was the first contained nuclear explosion, suggested Calif. A detailed report was prepared concerning the feaa- to many in the petroleum industry that perhaps a nuclear ibility of NE stimulation of a natural gas reaervoir,4 in- explosive could be.’used to stimuIate ~etroleum _p~xidc= __clud]n~resuka___ of the site evaluation and a preliminary de-——.. — tion, for here was an enormous quantity of erwrgy stored sign for ~h~p<;h’e=~”e~ep~ “w= ‘pTep

Generai Effeets of Nuclear Explosions Gasbuggy Experiment Before discussing the plans and predicted results of the Site Seiection Gasbuggy experiment, background information on the ef- Criteria for selecting a test site were: (1) Iow-pefmea-’ fects of nuclear explosions should be of interest. Each of biiity, depietion-drive reservoir in which conventional stim- us is famiiiar, through dwcriptions and photographs, wi~ ulative methods are inadequate, (2) reservoir with ade- some of the effects. The mushroom cioud has become a quate thickness to effectively use the anticipated effects of familiar pictoriai sight of the atomic age. Fig. i is a pho- tograph of the Plowshare Sedan burst at the Nevada test site in Juiy, 1962, A 100-kt thermonuclear explosive buried and detonated at a depth of 635 ft in desert al- luvium threw this mass of dust and rock particles high into the air. Although the Sedan detonation was designed as a cratering experiment (note large crater in Fig. 2) and the effects are not applicable to a reservoir-stimuia- tion experiment, it demonstrates the enormous releass of energy associated with a nuclear detonation. In a contained detonation such as Rainier and many Downloaded from http://onepetro.org/JPT/article-pdf/18/02/139/2224539/spe-1273-pa.pdf/1 by guest on 27 September 2021 others, however, no rock or radioactive material is vented to the surface. What happens is illustrated in the sequen- tial, schematic drawings in Fig. 3. In a fraction of a mi- crosecond, the explosive materials are vaporized and a rapidly growing fireball is formed. Heat and shock rapidly move outward, vaporizing, melting and crushing the sur- roundhg rock and forming a cavity. Within seconds or minutes after the detonation, the cavity cools, the roof us- ually coilapses and a cylindrical chimney of broken rock develops upward as the cavity fills with, rock falling from Fig. &PIowshare Sedan crater (courtesy, Lawrenee the roof, Essentially all of the radioactive fission and ac- Radiation Laboratory, IAverrnore, Calif.) * tivation products are fus~d into a glassy substance and buried at the bottom of the cavity under rubble. Radiating outward from this cylindrical chimney are fractures in the surrounding rock. Fig. 4 is a phot&raph of one of the two cavities that so far has not collapsed completely—Gnome. In a rock- srdt formation near CarIsbad, N. M., 1,200 ft below the surface, this cavity (about 70 ft high and 165 ft in diame- ter) was formed by the detonation of a 3-kt explosive. When the cavity was first entered some five months after the detonation, the temperature was about 140F and humidity was nearly 100 per cent, The residual radioactivity background was quite low. Petroleum reservoir cores and crude oil samples placed 100 to 400 ft laterally from the Gnome explosion were subjected to shock energy, high pressures and radiation. These samples were- reeovered and analyzed, and only minor physical or chemical changes were observed,6’0 Fig. 3-Predieted scqucndal plmses from detonudon of nuclear explosive to minuteu af terwtwd.

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Fig. l—PIowshare Sedan burst dmrtly after detonathn (courtesy, Lmvrenee Ra&~ Laborato~, Livtwmo~ Fig. ~Piowshare Gnome cavity (eourteay, Lawrenee ● . Radiation Laboratory, Livermor~ Caiif.).’

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the proposed nuclear expIosion, (3) reservoir deep enough to’ the general Iow permeability of the sand deposits ex- to cotdlne the explosion but not so deep as to result in cept where networks of natural fractures mist, The reser- excessive emplacement and testing expenses, (4) location voir is contained by the overlyhtg 100-ft thick Fruitland reasonably remote from habitation but easily accessible, formation, consisting predominantly of sandstone, shale and (5) adequate drilling in the surrounding area to pro- and siltstone, and the underlying Lewis formation, over vide needed production and subsurface data, yet not so 1,500 ft thick, consisting primarily of shale, highly developed as to be subjected to. heavy liability for Fig, 7 shows locations of Pictured Cliffs wells drilled possible damage to existing wells and surface facilities. in the vicinity of the Gasbuggy site. Predicted reservoir The location selected in Sec. 36, T, 29 N., R. 4 W., properties at the ..Gasbuggy site, based on” evaluation of Rio Arriba County, N, M,, is situated in the northeastern these wells, are permeability, 0.14 md; porosity, 11 per part of the San Juan Basin (Fig. 5). The immediate area cent; gas saturation, 41 per cent; formation pressure, 1,260 is both remote and uninhabhed, yet readily accessible by psi; formation temperature, 117F, and net pay thickness, paved highway. The nearest sizable town is Farmington, 190 ft. N. M., 70 miles to the west, with a population of about These values result in a calculated amount of in-place 20,000. The nearest community is Duke, N. M,, approxi- gas of 33 MMcf/acre which, for 160-acre spacing, would mately 20 miles to the northeast, with a population of bss 5,280 MMcf. The history of most wells in the area is D about 500. The Gasbuggy site is within the Carson Na-

that, after- only moderate flush production resulting from Downloaded from http://onepetro.org/JPT/article-pdf/18/02/139/2224539/spe-1273-pa.pdf/1 by guest on 27 September 2021 tionai Forest and adjacent to the Jicarilla Apache Indian conventional completion, daily gas deliveraF1lity stabilized Reservation. The surrounding area contains mesas and at less than 100 Mcf. It is predicted that only 10 per cent “ canyons and the usual bench-type topography generally of the in-place gas could be recovered in a 20-year period . associated with these surface features. Elevations in the from a. well at this location completed with the present area range fronK7,000 to 7,200 ft. NO streams of any con- stimtdative method — selective perforating and hydraulic sequence are near the site. fracturing. Formations underlying the site range in age from Pre- cambrian to Eocene and have an estimated 12,000-ft Experimental Design thickness of sedimentary rocks. In the Central Basin pro- Primary objectives of the experiment are to determine per, gas is produced from formations of Cretaceous age, (I) change in productivity of existing wells within effec- mainly from the Pictured Cliffs, Mesaverde and Dakota tive range of the shock effect, (2) extent of effective range formations. The sequence and thicknesses of these Cre- of the shock effect, (3) productivity of a post-shot well taceous formations expected to be encountered at the test drilled into the chimney, (4) increase in ultimate recovery, site are shown in FVg, 6, The Pictured Cliffs formation should be encountered at .a depth of approximately 3,850 ft and composed of in- ,. terbedded sand and shale deposits constituting a gross in- — terval of 300 ft. In this part of the basin, the Pictured OJO Alamo sadsf one Cliffi formation is a low-productivity reservoir attributed __i!l -iFOwmtt— stole I /’ sod Kirllond shals ; 3600’ ~ ~mifiglon sond$tane I 1’ ,, W50’ ,%J .

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and (5) degree to which radioactive contamination of gas Predicted fhdergmmnd Effects will be a production problem. Fig. 9 illustrates predicted underground effects. From Two pro-shot wells will be drilled. The 5rst will be data’ resulting from 34 contained shots in tuff, salt, allu- drikd approximately 100 ft from the emplacement hole vium and granite, scaling factors for predicting physical to confkrn by intensive coring and analysis the absence effects of contained nuclear explosions have been retlned of mobtle water in the formations immediately above and to the point that *principal effects may be predicted withh below the Piotured Cliffs formation and to evaluate res- 8 per cent. ervoir conditions and tIow behavior of the Pictured Cliffs The cavky created by the ffreball is roughly spherical formation at the site. The second test well will be drilled in shape and its radius R. can be approximated by: approximately 200 ft from the emplacement hoIe and will provide additional condrmation data. Both pm-shot wells will later provide data on extent of fracturing. The pm-shot wells and the emplacement hole may be located as shown on Fig. 8. where C = constant which varies with rock type (from Upon cotimation of suhabiiity of the test site from 261 for granite to 343 for tuf’), W = yield, kt; p = over- data obtained from the pre-shot wells, the emplacement burden, density in gin/cc; and h = depth of burial, ft. hole will be drilled to accommodate the nuclear explosive The Ciasbuggy cavity radius is predicted to be 65 ft US- immediately below the base of the Pictured Cliffs forma- ing values of 300 for C, 10 for W, 2.3 for p and 4,150 for Downloaded from http://onepetro.org/JPT/article-pdf/18/02/139/2224539/spe-1273-pa.pdf/1 by guest on 27 September 2021 tion at 4,150 ft, and will later furnish data regarding the h. depth of the point of casing collapse following detona- Volume of the cavity becomes distributed as voids be- tion. Present design stipulates that explosive yield will be 10 kt, or about 5,000 times greater than the energy obtained from 1,000 qt of solidified nitroglycerin. An explo- +yO_ (%,4W ,,68”s - 6S” sive yield of 20 M also is being considered. Gh!nmr IEdlv, - 65’ Chmm, bwhl - WQ’ As soon as practical, a post-shot production well will be m“”! r,%t,,ln+ - 195’ 1. ew” driied into the chimney zone overlying the point of detonation. Two additional post-shot wells will be drilled to Emwmlmt hi+ . Fy& further evaluate the effectiveness of NE stimulation. These 6“ ODw,irq

wells will be located at distandes and directions from the lnl*tnll,,#stiles a cola bmr.fs,,M, emrdacernent hole to be determined after post-shot eval- uat~on of the re-entry well, the two pre-;hot test wells and the existing wells. .———. .—— —-- .-- —- ___ gp~h ~,g(.~ __ _ - ———— . Op AbO Ie+mdwl ------.—- ..— — —— . ———— — II furf 10”6 Ihmothil 1111

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tween the fallen rock fragments in the’ resulting chimney, the proposqi location. F1OWcalculations were made using Radius of the chimney will be approximately equal to the reservok properties previously listed. Table 1 gives that of the cavity. Height of the chimney will be four to results of these calculations assuming 160-acre well spac- five times the cavity radius (depending on rock type), or ing. The average daily capacity for each year is based on about 300 ft. producing into a 500-psi gathering system with a reduc- Vertical fracture heights can be predicted with reason- tion in line pressure when necessary tomaintain the con- able accuracy. Data from post-shot re-entry drilling show tract rate. Future gas production is scheduled on the bas- that the extent of fractures vertically above the shot point is of a daily contract rate of 1 Mcf/D for each 8,000 is approximately equal to six cavity radii. Fracturing has Mcf of reserve to insure an even supply of gas over an not been observed at distances greater than 11/2 cavity extended period of time, Predicted gas recovery after 20 radii below the shot point. Therefore, for the Gasbuggy years foilowing nuclear stimulation is 3,520 MMcf, or 67 event, it is predicted that vertical fractures should extend per cent of the original gas in place (5,280 MMcf), This approximately 100 ft above and below the Pictured Cliffs is a sevenfold increase over the predicted recovery (537 formation. As the Fruitland, Kirtland, Ojo Alamo and MMcf) from a conventionally completed well at the same Lewis formations are believed to be impervious and not location. to contain mobile water, fracturing beyond the gas-produc- Similarly, Tables 2 and 3 summari% gas recovery and ing horizon should cause a minimum exchange of fluids. deliverability based on the existence of offset producing Downloaded from http://onepetro.org/JPT/article-pdf/18/02/139/2224539/spe-1273-pa.pdf/1 by guest on 27 September 2021 The extent of lateral fracturing cannot now be accur- wells for 160-, 320- and 640-acre spacing, Predicted re- ately predicted — Boardman et al.’ reported that lateral covery as a result of nuclear stimulation increases with fractures can be expected to extend about three cavity ra- larger well spachtgs although lower percentages of the in- dii from the detonation point. This concision was based place gas are produced (Table 2). Recovery values for on observations of significant fractures encountered dur- larger well spacings should be considerably higher if pro- ing post-shot exploration. duction continues past the assumed 20-year period, as deliverability at that time should be well above an economic The first attempt to determine fracturing effects of rate. nuclear explosives as applicable to stimulation of oii and gas production was made in 1963 in conjunction with The obvious benefit from NE stimulation is an increase Project Shoal, a 12-kt nuclear detonation at a depth in gas recovery. An additional benefit is the storage ca- of 1,200 ft in granite: Subsurface fractures resulting from pacity of a large effective wellbore from which gas couId the detonation extended laterally to a test hole 445 ft be produced at high rates for short intervals during peqk (5.3 cavity radii) from the shot point, and formation move- demand periods. ment along natural fauIt planes may have extended a Gas Contamination considerable distance beyond the test hole. The two types of nuclear explosives are fission and ““ The relatiotrship R, (radius of effective fracturing) = fusion. The type of explosive determines the radioactive 3 R. = 195 ft has been used for post-shot well-perform. isotopes produced, Major gaseous contaminants result- ante predictions, This is believed to be a conservative es- ing from fission are xenon 133, iodine 131 and krypton timate because, in application to the gas reservoir under study, hairline fractures provide effective permeability in- 85. Solid contaminants, such as strontium 90, cesium 137 creases and would be more extensive than fractures prev- and carbon 14, are also present, However, the majority of these solids are trapped in the melt at the bottom of iously observed from post-shot exploration, Also, naturai fractures and planes of weakness can be opened by the the cavity, and the remainder are filterable from the pro- blast, resulting in further extensions of permeability induced fluids, Because of the high tritium yieId of a fusion crease. process as compared to the resultant gaseous contaminants from a fission process, an ali-tlssion explosive is pro- Predicted Gas Production posed for this initiaI experiment. However, tracer quanti- The cavity or collapse chimney, togzther with the zone ties of tritium will be emplaced with the nuclear explosive of highly fractured rock beyond the cavity, comprises an for further evaluation of tritium-hydrogen exchange reac- expansive, permeable volume — the extent of which in tions. thk low-permeability reservoir can be considered as an Sixty days after the Gasbuggy shot, gaseous radioiso- exceedingly large effective wellbore resulting in increased flow rates. This large effectiye wellbore will also act as a storage cavern from which gas initially can be produced at high rates. As gas is produced, continued flow takes , \ TOP of sand place across the wellbore boimdary. ‘After the storage volume is-depleted, deliverability is the rate of flow cross- ing the boundary. If gas production ceases, gas will con- tinue to flow into the wellbore until an equilibrium pressure is reached. Fig. 10 is an ideaiized representation of the stimulative K= 0.14 md effects as applied to radial fiow concepts. The designated \ parameters are: R., radius of chimnew R~, extent of effective fracturing or radius of effective wellbore; K, natural ~ o“ formation permeabili~ K,, permeability of fracture zone; and K., oermeabilitv of chimney. Because of the uorous “-— -and-p~~-eabIe-gatu&-of-tht&ch;rntieyc-R~ car%e-~onsid--” -- -—r —-.—..+----m m.e{-e{.,QM-—.—-.. . ----- ered as a minimum effective wellbore, Radial flow calculations show further that if K, >10 K, R, cart be used as the effective wellbore radius. . AR attempt was made to predct gas recovery from , , Fig. I&Radial flow concept of increased eff+ve both a conventional’ well and a nuclear-stimulated well at weIlhore-l%oject f-%sbuggy. -. .

TASLE I—PREDICTEO GAS ~ODUC?lON FOR CONVENHONA1Cf3MPlETlClN AND NUCLEAR STIMULATED WELL, PICTURED CLIFFS FORMATION, 160.ACRE SPACING — PROJECT GASBUGGY

CGS volumes am expmmed ct a pressure b.m of 15.02S psla ahd 60F

COnventlOrral Cempletkt Nuclear S!lmulatlon Pmdtrctlan ?mducfian

Aver~Meti~Dcrclty pu;; cumulative Avera~cfzaCDoclty Kll:ll pwmi cu{ym&ve Year :$!4 IMMcf) 260 ●SS -z- 32 ‘ 1 ,s00 **525 7 192 ; 235 88 32 64 1,3s0 S25 192 384 3 210 8s 32 96 1,260 52s 192 676 4 185 S8 32 128 1,150 525 192 768 5 160 88 32 160 1,050 525 192 960

6 140 sa 32 192 950 525 192 1,152 7 115 88 32 234 S40 525 192 1,344 ●**142 8 8s 32 256 760 525 192 1,S36 ‘ 9 122 Ss 32 288 640 525 192 1,728 10 106 S8 32 320 540 525 ;192 1,920 ●**700 11 90 8S 32 252 526 192 2,112 12 75 7s 27 379 610 525 192 2,304 13 tsa 75 27 406 ?670 525 192 2,496 Downloaded from http://onepetro.org/JPT/article-pdf/18/02/139/2224539/spe-1273-pa.pdf/1 by guest on 27 September 2021 14 75 75 27 ~ 433 5B0 325 192 2,6SS 15 65 65 24 457 510 510 186 2,874

16 67 57 21 47s 440 440 t 61 3,035 17 49 49 la 496 390 390 142 2,177 18 42 42 15 51 T 350 128 2,30S 19 38 38 14 525 :fl 310 112 2,41S 20 34 34 12 537 280 2s0 102 3,520

●Ddlv contract rate based on recevwable gas reserves of 700 MMcf. ●*Dally contract r4te based on recoverable s0s reserves Of 4,300 ~Cf. ●.* Line pressure reduced fmm 50010300 P$i. tline premure reduced from 200 fa 100 PSI. , TASLE 2—PRE121CTED STIMULATED GAS RECOVERY FROM should Drovide needed data to evaluate more accurately PICTURED CLIFFS WELL — PROJECT GASBUGGY / the tt%m problem when thermonuclear explosives are Recovery used for production stimulation. well Smxin6 Gas Irr Place MMcf Per cent (k (MMcfl Conventional Nuclear Conventional Nuclear Safety Aspects : —- — 160 5,280 537 s 10 67 The expe~imental design for Project Gasbuggy was 32D 10,560 S,l 70 49 made with full consideration of all safety factors, includ- 640 21,120 6,120 29 ing the possibility of (1) venting radioactive contaminants to the atmosphere, (2) damage resulting from ground

TASIE 3—PREDICTED STIMULATED GAS DELIVERABILITY FROM shock, and (3) contamination of produced gas and ground FICTURED CLIFFS WELL - PROJECT GAS8UGGY water.

Irritlal Stablllzed Avaras~M~;~Drablllty The danger of atmospheric contamination, because of well Spaclns Delhrabllltry, Mcf/D venting radioactive gas to the surface through fractures de- Nuclear Conventional Nuclmar —. (acre) &nvOntlemd veloped by the explosion or by failure of the stemming in 160 275 1,560 75 480 320 1;350 710 fthe emplacement hole, is considered extremely remote. S40 1,1s0 840 “This conclusion is based on evacuation of effects from over 100 previous underground detonations, Although the experiment is planned for complete containment, a ntaxi- topes could be present in tiie chimney gas in the follow- mum credble release mechanism will be hypothesized, and ing amounts: the U.S. Weather Bureau will prepare a predicted fallout pattern. Weather predictions and on-the-spot observations Xenon 133 (5.3 day half-life) 2,S00 curies made by the weather bureau wiil determine whether deto- Iodine 131 (8 day half-life) 7,170 curies nation wiil occur on scheduie or be postponed so that Krypton 85 (10.3 year half-life) 200 curies any conceivable failout would be restricted tb an accept- A curie is a unit measurement of radioactivity based able area. on 1 gm of radlurn, specifically, it is the activity of any The U.S. Public Health Service wili. make pre-shot substance having, 3.7 X 10’0 disintegrationa/sec. As a re- surveys of population and livestock within the potential sult of the decay piocessi assuining 100 MMcf of gti in faIlotit area to “delermine the precautions necessary to safe- the chimney, the concentration of xenon &comes negli- guard the public. A preliminary survey within a iOO-mile gible after iivemonths, and that of iodine after 10 nionths, radius of”the teat site indicated that” only routine precau- {’ iSrypton 85 has a relatively long half-life and will remairt tions will be newssary. Aiso, the heaith service wiii per- in the gas essentially at its original concerttr@ion (7 X 10-’ form post-shot monitoring, such as collecting air, water, microcuries/cc) for many tionths. Considering the levels milk and vegetation sampies — normal foiiowup proce- ‘-. of radioactivity pred:cted, the natural decay of these radlo- dures. ‘~sotopea; dlltttio~-otcortta~inated-chirnney-gaa-with-cleau’ — fie=Federal-AviatiomAgmcy-wiIi-prepar&amair.sptice-- - gas from the reservoir, dilution of produced gas with ciean ciosura plan to safeguard aircraft from any vented ma- gas from. . other field wells and.. di]uticms. . - during consumer terial. An oft-site radiological safety program will provide - sion ex- monitoring personnel, .telemetry, air sampling, counting plosion wiii not be a serious problem. equipment, decontamination facilities and medical-care fa- The t~tiutn tracer to be iruxsrporated in the experiment < cilities, ...... ,......

‘lhe post-shot drilling program will remain under the “control of the AEC as long as is necessary to protect the public safety. Concentration of radioactivity in the chimney gas will be determined, and suitable testing and production techniques will be used to prevent radiation haz- ards, The immediate test area is uninhabited, and the only installations subject to damage from ground shock are existing gas wells and pipelines. Results from previous testing indicate that no damage to cased hoks should occur at distances beyond 1,300 ft (600 W’P). Only one well is within this range, and shock damage to this well will be ‘OOt--- considered as part of the experiment, Although contamination of ground water” by radioiso- 100 I I 1 1[1111 I I I 111111 10 m m WJo I topes can be a serious hazard, data from wells drilled in “am,W40” the test area indicate no mobile water in the formations Fig. 11—AEC projected charges for nuclear explosives. that might be affected by the test. No ground water is Downloaded from http://onepetro.org/JPT/article-pdf/18/02/139/2224539/spe-1273-pa.pdf/1 by guest on 27 September 2021 used for water supply purposes in the area, and the near- grams can be designed, The Bureau of Mines and the est existing water wells are about 50 miles away and 1,700 AEC welcome discussions with industry concerning addi. ft updip in the Ojo Alamo formation. tfonal tests. Only from the analysis of production data ob- CoSts turdTime SclreduIe tained by this and future experiments can the economics” Cost of the experiment is estimated at $3,000,000, ex- of NE stimulation be determined. Many years probably clusive of explosive and detonation costs. will be required before nuclear stimulation could be Projected chargeu for nuclear explosives cited by the classed as a standard field technique. AEC range from $350,000 (10 kt) to $600,000 (2 mega- tons), with a straight-line exponentird interpolated price Acknowledgments range between the two values (Fig. 11), The economics Cooperation and assistance of personnel of the El Paso of naturaI gas stimulation through use of nuclgar explo- Natural Gas Co. and the AEC San Francisco Operations sives are difficult to predict, The experiment naturally will OtRce are gratefully acknowledged. be more costly than subsequent use for production. How- ever, it should demonstrate the technical practicability of nuclea~ ,stimulat ion and the economics can be more closely References determmed from data obtained. . 1.\Vatkirrs, J; \V. imrl Anderson, C. C. t Polential o] Nuclear h. A proposal by, EPNG that this test be conducted was pt!osivesjor Producing H drocarbons from Deposits oj Oil, Nut- ural Gas, Oil Sk!c and Far Sands in the United States (1964) submitted to the AEC on June 17, 1965. I?hal evaluation Information Circular 8219, USBM. of the proposed test by the AEC and its contractors is es~ 2, Atkinson, C. H. and Johamen, R, T.: A S@y o/the Feasibility sentially complete and approval was expected by t!’e end o/ Using Nuclear Expfoswns to Increase Petroleum Recovery of 1965, Drilling of the first pre-shot test. well : w “,s@t (1964) R. L 6494, USBM, , shortly after authorization and both pre-shot well: . hould 3. Atkinson, C. H, arid Lekas, M. A.: “Atomic-Age Fracturing be completed in two months. Pre-shot production tests May Soon Open Up Stubborn Reservoirs”, Oil & GUS Jour. will require six months. Therefore, if the present timing (Dec. 2, 1963) 154. program can be met, the shot can take place in early fall 4. El Paso Natural Gas Co,, Bumxm of Mbies, U.S. Atomic Err- of 1966. ergy Commission, Lawrence Rrdation Laboratory-Livermoro: “Project Grwbuggy”, published by El Paso Natural Cas Co., El Paso, Tex. (my 1A 1964). 5. Coffer, H. F., Bray, B. G. Knntsmr, C. F. and Rawsnn, Il. E.: Previous work has resulted in the conclusion that stim- “Effects .of Nuclear Explosions on 011 Reservoir Stimulation”, Jour. Pet. Tech. (May, 1964) 473. ulation of natural gas reservoirs with the use of nuclear explosives is technically feasible.. Calculations showing po- 6. Johansen, R. T,, Armstrong, F. E. and Watkins, J. W.: “Shock Induced Transitions—Part 11. Enca srrlation mrd Results of Ex. tential benefits of this stimulative method are based on posingPetroleum Industry Samp fes, Project Gnome”, U.S. anticipated fracture effects. The true stimulative effective. Atomic Energy Commission Plowsl]are Program, PNE-l12F, Part ness can be determined only by experimentation, An experi- 2 ( Nov. 13, 1964) 3-42. ment has been designed to test this effectiveness. Also, de- 7, Botu-dman, C. R., Rabb, D. D. and McArtbur, R, D.: Charac. termination of the extent” that radioactive contamination teristic Effects of Contained Nuclear ExpiosiQns jor Evalwtwn is a production problem and investigation of methods of oj Mining Appticatwn, Report UCRL-7350, Rev, I, hw rence Radiation Laboratory, Livermore, Calif. (Sept. 12, 1963). handling the produced -fluids are itttegral @arts of the experiment. 8. Atkinson, C. H.: Subsurface FractILring Frol~t a Nuclear” ~et- onution in Granite, U. S. Atomic Energy Comrnfsdon-Buresrrof Project Gasbuggy is an initial “experiment designed to Mince Report PNE-3001 (Nov.,MM). ** be as simple as possible,. With encouraging ~remdts, more testing in other areas at various depths, and with various EDITOR’S NoTE: PICTURES AND BI&JRAPHICALSKETCHES yields of single” and multiple detonations are logical fol- OF D. C. W-D, C. H. ATKINSON AND J. W. WATKINS AP- lowup steps before practical, field-wide developmental pro- PEAR ON PAGE 203. — ._L.-... —— —_ ——. —._ ,...... - —,