TID-4500, Category UC-35 Nuclear Explosions — Peaceful Applications

LAWRENCE UVERMORE LABORATORY UnivBrai»o(Cajffafrea/UvBn7iore,Calf(0fni3/94550

UCRL-51226 AN ANALYSIS OF GAS STIMULATION USING NUCLEAR EXPLOSIVES B. Rubin L. Schwartz D. Montan

MS. date: May 15, 197 2

-NOTICE- This report was prepared as an account of work sponsored by the United States Government. Neither the United States nor the United States Atomic Energy Commission, nor any or their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, com­ pleteness or usefulness of any information, apparatus, product or process disclosed, or represents that its use would not infringe privately owned rights.

R5747

BJsrtBeunow w THIS B6COMENT B wm% Foreword

This report is an updating and expansion of our previous report on nuclear gas stimulation issued in April 1971 and covers the same topics. Where appropriate, the previous text and organization have been used. New topics presented in this report are the gas production results from Rulison, a proposal for large-scale commercial development together with possible plans for delivery of the gas to market, and the calculated radia­ tion exposure to the consuming population from use of the gas associated with these delivery plans. In addition to the produc­ tion and economic analyses previously presented for a typical nuclear stimulated well in the Green River Basin, we have included a similar analysis for a well representative of the Piceance Basin. Gas sales prices for these examples have been adjusted to 40£ per thousand cubic feet instead of 30£ since it appears that this may be consistent with gas prices in the 1975-1980 period. During the past year the major event of interest to gas stimulation was the successful test in the Miniata Event of the Diamond explosive. An expanded discussion of that ex­ plosive is included here.

-xi- Contents

Foreword ii Abstract X Summary 1 The Need for Gas 5 Concept of Commercial Gas Stimulation • . . .8 Description of the Concept 8 Currently Proposed Joint Industry-Government Experiments 11 Potential for Gas Stimulation 13 Relationship of Nuclear Stimulated Gas to Proved Reserves and Potential Supply 15 Gas Production from Nuclear Stimulated Wells 16 Technical Feasibility 16 Gas Flow Analyses of Nuclear Stimulated Wells 16 Gas Production from Single Wells 20 Comparison with Conventional Wells in the Same Region 21 Possible Schedule for Commercial Production of Gas by Nuclear Stimulation 22 Economics of Gas Production by Nuclear Stimulation 24 Estimated Cost of Commercial Gas Stimulation 24 Single-Well Revenue Estimates 26 Cost Comparisons of Alternate Gas Supplies ...... 28 Potential Markets and Delivery Schedule 29 Radioactivity in the Gas 32 Environmental Impact 38 Well Construction 38 Seismic Effects 39 Seismic Aftershocks 39 Disposal of Radioactivity in the Chimney Gas 41 Groundwater Effects 42 Effects on Other Mineral Resources .43 Public Acceptance 44 Technical Development Programs for Achieving Commercial Usage 46 Development of the Gas-Stimulation Explosive 46 Diameter 47 Gaseous Radionuclide Production 47 Downhole Conditions 47 Sequential Firing 48 Cost 48 -iii- Technical Development Programs for Achieving Commercial Usage (Continued)

Nuclear Effects 49 Explosive Operations System 5^

Gas-Reservoir Production Technology 51 Policy Issues Requiring Government and Industry Action 53 Government Actions 53

Industry Actions 53 Joint Actions—The Technological Development Program .... 54

Benefits 55 References gg Appendix A. Alternative Gas Supply Methods gg Conventional Exploration in the U. S. and Canada gg Import of Liquefied Natural Gas gg Synthetic Gas gi Nuclear Stimulation gl

Competition for Investment Capital 62

References 63

Appendix B. Radioactivity in the Gas 64 Uniform Mixing Model 54

Separate Pipeline for First-Year Gas from New Wells 65 Population Dose gg

-iv- AN ANALYSIS OF GAS STIMULATION USING NUCLEAR EXPLOSIVES

Abstract

The United States presently is faced to an annual gas production rate of 3.4 tril­ with a developing crisis in its energy lion cubic feet by the year 2000. Based resources and specifically in its supply on a hypothetical example in which all the of natural gas. The use of nuclear explo­ gas would be used in California, we cal­ sives in the stimulation of low-permeability culate that the average whole-body radia­ gas reservoirs has the potential of supply­ tion exposure to individuals in the Cali­ ing moi'e than 300 trillion cubic feet of fornia population would be between less gas, an amount greater than the nation's than 0.45 and 0.64 millirem/yr, compared present proved gas reserves. Two with the 170 millirem/yr average allow­ nuclear-explosive gas-stimulation experi­ able exposure to the population rec­ ments have produced a substantial quantity ommended by official guidelines. Compared of gas. We have made an economic proj­ with other alternatives for increasing U. S. ection of commercial production (after the gas production, nuclear stimulation appears successful completion of a research and to have advantages in terms of required development program) for nuclear- capital investment and gas sales price. explosive stimulation of wells in the A research and development program will Piceance and Green River Basins in be required to achieve this projected ca­ Colorado and Wyoming. The internal rate pability for nuclear-explosive gas stimu­ of return on investment varies from 7f to lation. The cost of this development pro­ 285% depending on the properties of the gram to achieve initial commercial reservoirs and the required number of production in about five years is estimated explosives per well, assuming a wellhead to be $100-150 million. We recommend price for gas of 40f per thousand cubic that a vigorous government-industry pro­ feet. We propose a schedule for the gram be conducted to develop this technol­ commercial development of the Piceance ogy to help relieve the shortage in natural and Green River Basins that could lead gas supply.

Summary

It is becoming increasingly clear that sidered, major deficits will still exist in the demand for gas in the U.S. is out­ some geographic areas (see Fig. 1). One stripping supply. In fact, the gap between potential source is from very low perme­ demand and supply is predicted to be so ability reservoirs that contain large quan­ large in the coming years that, even if tities of gas. Recovery of this gas by con­ all potential new sources of gas are con- ventional techniques is not economically

-1- feasible within the life of the wells, ously detonated at a depth near 6000 ft in bui the use of nuclear explosives offers the Piceance Basin in Colorado (Fig. 3). the potential of fracturing the rock and The Wagon Wheel experiment is planned producing, in effect, a very large diam­ for sequential detonation of five 100-kt eter well capable of substantially in­ explosives at a depth of 11,000 ft in the creased gas production. Green River Basin in Wyoming (Fig. 5). The U.S. Bureau of Mines has estimated For the present study we obtained the that 317 trillion cubic feet (Tcf = 1012 ft3) fracture radius for production calculations of gas is potentially available using nuclear by matching the early production from explosive gas stimulation techniques. This Rulison; the Rulison chimney consists of figure should be compared with the proved a high permeability zone extending out to reserves of 290 Tcf that are currently 2.75 times the initial cavity radius (Fig. 10). being produced at the rate of more than This is consistent with the extent of 22 Tcf/yr. fracturing measured in Gasbuggy. To date, two nuclear explosive gas We calculated gas productivity for stimulation experiments (Rulison and typical nuclear stimulated wells in the Gasbuggy) have been successfully fired. Piceance and Green River Basins. As Both wells have been reentered and have examples, three 100-kt explosives were produced gas for periods totaling 3j and assumed to stimulate a 2000-ft vertical 12 months, respectively. Each one interval in the Piceance Basin containing already has produced many times the 100 billion cubic feet (Bcf = 109 ft3) of quantity of gas produced in several years gas per section, and four 100-kt explosives from nearby conventional wells (Fig. 8). were assumed for a 2400-ft vertical The key to commercial nuclear explo­ interval in the Green River Basin con­ sive gas stimulation lies in obtaining taining 170 Bcf per section. Permeabilities sufficient gas production at a cost that of 10-40 microdarcies (/id) and 5-10 ^d, gives a reasonable return on investment. respectively, were assumed for the two Because drilled holes are expensive, regions. The corresponding 20-yr gas production can be maximized by firing a production from single wells in the two number of explosives in a vertical array basins is 14-31 and 21-35 Bcf, respec­ in the same emplacement hole. tively (Figs. 11 and 12). It is expected that the gas will be pro­ Based on these typical gas production duced by reentering the emplacement hole rates, a plan has been postulated for after the detonations (Fig. 2). The degree commercial development of the two basins. of stimulation depends on the size and the We assume that upon completion of a character of the fracture zone produced 5-yr government-industry research and by each nuclear explosion. pilot development program industrial To test and verify this principle, two development teams could begin com­ additional experiments have been proposed mercial field development in 1977. Three by industry that will employ multiple ex­ such operations in parallel might reach plosives. In the Rio Blanco experiment, a continuous nuclear stimulated well con­ three 30-!'.t explosives will be simultane­ struction rate of 100 wells per year by

-2- 1981 (Table 5). Using gas productivities coal gasification, or import of liquefied corresponding to permeabilities of 40 natural gas (Table 10). Gas sales prices and 10 116 in the Piceance and Green River from nuclear stimulation should be lower Basins, respectively, and making the than from any other source except con­ conservative assumption that the wells ventional exploration. would produce for only 20 yr, we find that The total gas production rate resulting gas production would start in 1977 and from the commercial development pro­ rise to a steady state production rate of gram proposed here c^uld furnish a large 3.4 Tcf/yr by the year 2000 (Fig. 13). portion of the needed supply in selected We also make an economic evaluation major market areas; for example, 80% of the production from single wells in of the demand of the state of California the two basins. In this analysis we con­ could be supplied in the year 2000 (Fig. 17). sider the federal royalty, severance, and To evaluate the radiation exposure to ad valorem taxes, administrative costs, the population resulting from iow levels and lease operating expenses in calculating of radioactivity in the gas, we considered the future net revenue from one well year two methods of distribution of this geis by year, as well as the present worth of in California. If all the gas were uniformly 20 years' future production. The proj­ mixed with other out-of-state gas supplied ected nuclear development costs are to California and consumed in general use, estimated at about $2.41 million per well the average year-2000 individual exposure in the Piceance Basin and $3.34 million would be 0.45 millirem (mrem) per year. per well in the Green River Basin (Table 7). The maximum individual exposure would Using this cost and a price of 40f per be 0.7 mrem/yr, and the population dose thousand cubic feet (Mcf), the internal would be less than 14,000 man-rem/yr. rate of return on invested capital varies Alternatively, the 0.47 Tcf of more from 7.5 to 28.5%, depending on the highly contaminated gas occurring during permeabilities encountered (Figs. 14 and the first year of new well production 15). If depletion allowance, depreciation, might be collected into a separate pipeline and corporate federal income tax are and consumed in power plants; the gas included and one assumes that the loss in produced in later years and representing the development years can be written off the major portion would be essentially against other corporate profits, the in­ contamination-free. In this case, the ternal return on investment is slightly average individual exposure would be increased. less than 0.11 mrem/yr and the maximum A comparison of nuclear stimulation exposure would be less than 2.1 mrem/yr. with the several alternative ways of in­ The population dose would be lowered to creasing gas availability shows that the less than 2000 man-rem per year. cost of research and development, the These dose levels should be compared required capital investment, and the time with the 170 mrem/yr average allow­ needed to achieve a new production capa­ able exposure to individuals in the bility of 1 Tcf/yr are less than or com­ population at large as recommended by petitive with conventional exploration. the former Federal Radiation Council

-3^ (now a part of the Environmental Protec­ per year range in each of the two tion Agency). The California population basins. exposures should be compared with doses Minimal amounts of radioactivity from natural sources of 2.3-3.5 X 10 man- would be released in the local environ­ rem/yr or doses from medical sources ment that could enter the biosphere. of 2-5 X TO6 man-rem/yr (Table 13). Flaring of gas should not be necessary As in all considerations of radio­ except for production testing of wells in activity, the exposure should be made new and untested areas. As exemplified as low as possible and the risk must be by the proposed Rio Blanco releases, evaluated against benefit. The benefit such flaring would release only minor in this case is the availability of sub­ amounts of radioactivity. It is expected stantial quantities of a clean (low sulfur that tritiated water produced with the gas content), inexpensive, convenient fuel. would be disposed of without environmental The radioactivity levels appear to be release, possibly by reinjection under­ small compared with established recom­ ground. mended guidelines and with natural The economic projections and estimates background. However, an official regu­ of radiation exposure presented here are latory framework for distribution and based on what might be achieved after a consumption of the gas does not exist at successful research and development present and the acceptability of these program. One feature of such a program projected levels of radioactivity has yet is the design ard testing of a small- to be established. diameter, low-tritium, inexpensive nu­ The principal local environmental clear explosive for sequential firing. effects resulting from nuclear stimulation Lawrence Livermore Laboratory suc­ would be those associated with construc­ cessfully tested a prototype explosive tion of the gas well, access roads, electric (characterized by the name Diamond) in power lines, tnd gas pipelines. Also, the Mi ni at a Event at the Nevada Test Site there would be the seismic effects result­ on July 8, 1971. In a typical gas field ing from detonation of the explosives on environment this 80-kt explosive is proj­ a few selected days during the year. ected to leave less than 2000 curies of Based on experience from Rulison, from tritium. Further development on harden­ the Salmon experiment in Mississippi, ing this explosive to withstand sequential and from many experiments at the Nevada firing is yet to be accomplished. Test Site, the expected damage to struc­ Other development tasks also remain tures would be low in the remote loca­ to be done. Ways must be found to create tions where nuclear stimulation would connected fracture regions from which be conducted. Such damage as does gas can be most economically produced. occur should be limited to architectural Operational systems must be developed effects such as cracking cf plaster or that are safe and efficient. Lautly, data fallen bricks. Estimates of the total are needed on which administrative deci­ value of such damage claims to be sions regarding commercial use would be paid are in the $100,000 to $200,000 based. Each of these areas requires a specific research and development can be provided, perhaps by support of effort. nonprofit research organizations. Several policy actions must be taken Ultimately, public acceptance of by government and by industry for the nuclear gas stimulation will depend on commercial development program en­ public awareness of the fuel shortage, on visioned here. In addition to funding a a realization that the radioactivity asso­ major share of the development program, ciated with the gas is extremely low, and the government must adopt legislation on an awareness of the direct financial that permits commercial use of nuclear benefits from use of this resource. As explosives and must announce how much examples of these financial benefits, by is to be charged for these explosives. 1991 the nuclear stimulation industry Also, pricing policies for the sale of the would have a product sales value of about gas and regulation guidelines for the $1 billion per year (Table 15). Govern­ distribution to consumers must be es­ ment revenues in the form of local and tablished. In addition, information on statetaxes plus federal royalties would explosive characteristics such as diam­ amount to $180 million in that year. If eter and amount of residual tritium must instead of producing this gas the equiva­ be declassified so that industry can lent quantity of energy were to be obtained make reliable design and economic through import of petroleum, the effect studies. on balance of trade would represent an Industry must be willing to assume its outflow of $1.3 billion. share of the development program cost. In addition to these direct monetary A small number of companies so far have benefits, there would be the economic borne the burden of supporting the tech­ stimulus to local and state commerce nical development of gas stimulation. of this new industry and, overall, the Industry should find ways by which the benefit to society of providing a large additional necessary development funds source of clean, inexpensive energy.

The Need for Gas

Recently there has been a growing gas supplied to its "interruptible" cus­ awareness in the X3. S. that there is an tomers in Cleveland and reduced the supply urgent need for increasing the country's to a number of industries by 7 5%, thereby supplies of natural gas. In addition to causing them to close down for 8 days warnings over the past several years by and forcing 30,000 employees to forego 3 leaders of the gas industry that proved working. Several cases are pending reserves ware being consumed at a rate before the Federal Power Commission greatly in excess of new reserve addi- in which gas transmission companies are 2 tions, the symptoms of an impending attempting to reduce the supply to dis­ shortage have begun to appear. As ex­ tribution companies. amples, in January 1971 the East Ohio That these are not isolated examples Gas Company invoked its right to limit is indicated by the directive issued in

-5' April 1971 by the FPC to ail U.S. gas 50 transmission companies to prepare plans for the order in which they will cut back Actual Projected / supplies to their interruptible customers / 40 when necessary.' Several gas transmis­ U.S. / ~ demand-; / sion companies already have notified their I // customers that no further increase in gas U.S. production J Alaska plus imports / services can be provided because of the production-7 — limited supply situation. / Overland / The past record of U. S. gas consump­ / imports-^/ LNG importsy // tion and its projection to 199 5 (if uncon­ strained by supply limitations), as given recently by the gas industry's Future Requirements Committee, is shown in Synthesized /"""- 7 Fig. 1. Also shown are the expected gas-J supplies of gas from domestic production, "Lower 48" production synthesized gas, pipeline imports, and liquefied natural gas (LNG) imports as U.S. production projected by the National Petroleum 1960 1970 1980 1990 Counoil. The notablt feature of this Year graph is the gap between supply and projected demand that appears in 1971 Fig. 1. U.S. natural gas demand and 7 and rapidly increases with time. supply. The Administration is fully aware of the impending shortage. In a recent precipitate discovery of major gas areas. address, the Secretary of Interior pre­ But I will not allow this program to dicted that the outlook for natural gas mushroom willy-nilly into an environ- supply, based on present U. S. reserves Q mental disaster." "is that supply will reach its limit by the Table 1 lists some of the ways by middle of this decade and, at that point, which additional gas may be supplied. In will have to adjust consumption to the addition to the comments listed there available supply. I intend to exercise relative to the total quantities potentially the following options to increase our available, it is important to note that the supply of natural gas. I will encourage rates at which these potential supplies domestic exploration and production, can be developed and delivered to U. S. explore the expansion of imports, and consumers are quite limited, as indicated foster the development of new techniques in Fig. 1. Factors likely to affect these in gas recovery and synthetic fuels.... rates of development may be (1) limited For the near-term solutions, I am hope­ availability of investment capital needed ful that the regular sales of United States to construct facilities such as exploratory Outer Continental Shelf and state offshore gas wells, coal gasification plants with their exploration and drainage leases will associated coal mines, or refrigerated

-6- Table 1. Possible alternatives for increasing U.S. natural gas supplies. Potential quantities8 (Tcf) Method Proved Potential Comments

Conventional exploration Onshore 225 613 Exploration now directed much deeper Offshore 39 238 onshore into deeper water offshore, Alaska 26 327 and into remote areas. 290 1178 Imports from Canadian proved reserves (53 Tcf) not Canada — ? available to U. S. Potential discoveries could be large; availability for export to U. S. will depend on Canadian policy. Liquefied natural gas imports South America 50 1967 proved reserves—not all available North Africa 135 for export. Europe and Japan compete Nigeria 4 with the U. S. for these supplies. Middle East 350 Synthetic gas Naphtha and Some Availability of imported naphtha and heavy-oil heavy oil for this purpose is uncertain. gasification Gasification of naphtha and oil are primarily for meeting peak loads. Sales price will be high, and imported liquids may be subject to import control. Coal 1750 Based on conversion of all the U. S. gasification strippable coal (140 billion tons) to gas at 50% efficiency. Nuclear stimulation 317 There is a large uncertainty in this value. The U.S. 1970 consumption was 22 Tcf.

LNG tankers and liquefaction and re- magnitude of that shortage in the coming gasification plants and (2) possible en­ years, it would appear that all possible vironmental const, aints on the develop­ sources of gas will be needed; projected ment of facilities such as new coal development rates of aU supply methods strip mines for coal gasificatior. Arctic will still fall short of meeting total gas transmission pipelines, or LNG potential demand. Gas provided by nu­ marine unloading and on-shore storage clear explosive stimulation of low- facilities. permeability reservoirs can supply an Therefore, in view of the imminent important fraction of the new supply shortage of natural gas and the apparent needed. Concept of Commercial Gas Stimulation

DESCRIPTION OF THE CONCEPT lating tight gas reservoirs because tremendous energy can be packaged in Large quantities of gas are known to a very small volume and emplaced through exist in low-permeability (or "tight") a drilled hole. The explosion produces reservoirs. The gas is present in the a region of broken rock called a chimney pores in the rock, but the pores are very and a fracture system that surrounds poorly connected. Gas may flow through and is connected to the chimney; as a minute fractures and connections between result, instead of producing gas from a the pores to the well, but not fast enough well 6 in. in diameter, the nuclear- to amortize the investment in conventional stimulated well produces gas from an wells. effective diameter of several hundred Many of these gas-bearing formations feet. in the basin of the Rocky Mountain area Many calculations have been made of are located at relatively great depths. the expected performance of such a On the average, total drilling and comple­ well. The results of gas production tion costs for conventional wells to depths calculations will vary according to the of about 5000 ft are approximately pro­ particular model and flow parameters portional to depth. For deeper wells they chosen to represent the stimulated under­ increase very rapidly; at depths of ground formations. However, with 15,000 ft the cost per foot of total depth reasonable assumptions there is general is four times as much as for shallow agreement that over an investment return wells. The relatively large investment period like 20 yr such a well may produce together with the low rate of gas produc­ 10 to 30% of the gas in place. A note­ tion from these tight formations makes worthy point is that if the return on in­ conventional wells unattractive, even vestment during the initial 20 yr is though the total reserves ultimately pro- sufficiently attractive to justify the proj­ duceable are very large. ect, there is the additional attraction that Some low-permeability reservoirs have the well may continue to produce for been made economically productive by the another 20 to 30 yr at only a slightly use of chemical explosives or by hydraulic diminished rate. Although the financial fracturing; however, this method has not present worth of such long-term future been successful in deep, tight gas reser­ production is relatively small, there voirs whose permeabilities are measured would be a strong benefit to the nation in microdarcies. Of course, should the in terms of stable proved reserves. price of gas increase substantially, some Other factors being equal, the increase marginal-permeability fields would be­ in well diameter alone might not lead to come economically feasible and increase sufficiently increased production to the gas supply. justify the additional cost of the nuclear The nuclear explosive gives a new stimulation method. However, it is be­ dimension to the possibilities of stimu­ lieved that concomitant factors may act

-8- to further enhance production. One such be tolerated, but adverse public reaction factor is the greatly increased number of and damage compensation will seriously separate gas-bearing lenses and strata hamper the project. Therefore, it is that are expected to be intersected by anticipated that the explosives would be the nuclear chimney and fracture zone fired sequentially, with perhaps 5 min as compared with the number intersected delays between detonations. In this way, by a single 6-in. hole. In addition, the each explosive can have several times drilled well-bore surface, which in con­ the yield that it otherwise would have if ventional wells is sometimes suspected simultaneous detonations were used. To of being sealed off by drilling fluids, will minimize inconvenience to the surround­ disappear over the entire height of the ing population and for efficiency in the chimney and the producing cavity will field operation, it is envisioned that in a communicate directly with the gas-bearing development of a gas field a number of formations. wells could be stimulated in one day, Figure 2 shows the concept of com­ followed by a period of no firing. mercial nuclear-explosive gas stimula­ To construct a well in this manner, tion. A number of explosives would it will be necessary to develop a special be emplaced one above another in the nuclear explosive that can survive the same hole to stimulate the greatest shock of the earlier detonations and still possible thickness of gas-bearing rock function properly with high reliability. and thus achieve maximum production. An alternative method of operation that This concept envisages that the emplace­ would eliminate the need for such a ment hole would be reentered after the hardened explosive could be that of em- detonation and used to produce the gas. placing each explosive after the previous This requires that the yields and depths one had been detonated. This method of the nuclear explosives be so planned still would have the advantage of maxi­ that the chimneys are connected by mum net pay thickness stimulated; how­ means of intersecting fractures or, ever, it would require the development alternatively, that a method be devised of a reliable downhole stemming procedure to keep the emplacement hole open that could survive the previous detonation between chimneys. and still permit safe emplacement of the The larger the explosive yield, the next explosive above. Both of these larger the fracture radius and the more operational methods will require de­ gas economically produced. While the tailed study to determine which one horizontal fracture radius is important, appears to offer the best tradeoffs in the amount of gas produced depends much technical feasibility, cost, reliability, more strongly, given the same permea­ and safety. bility, on the total thickness of the forma­ Reentry after the detonations could be tion fractures. The limitation of explo­ delayed for a number of months, if sive yield depends on the remoteness of necessary, to permit the decay of the site relative to surrounding towns. short-lived radioisotopes. In a proved Some seismic damage to structures may gas field, gas need not be released to .^T1 6*i*!©iSg» ••Mi rarin.ii ij

v*- QAS PBODOCINQ SANDSTONE

•••trr

% §*4 * - *i* -*i* 5 '*%fcl^*JjlA j ^'-»

J,

MUY SANDSTONe '-^h. -

$^.,r^./^'"l;".|

Fig. 2. Nuclear gas-reservoir stimulation. The reservoir is modeled after the Green River Basin in Wyoming. the atmosphere (flared) but could be tribute to the technical understanding of produced directly into the pipeline. nuclear gas stimulation: Carbon dioxide that is produced by the • Determination of preshot resc "oir explosion and mixed with the chimney properties; gas would be released to the atmo­ • Gas production through the emplace­ sphere. ment hole; Water produced with the gas initially • Calculation of the fracture zone; will contain low levels of tritium. It o Seismic motion measurements; may prove desirable to dispose of this • Radioactivity measurements in the water by reinjection underground, gas; possibly into the same well from which • Pressure measurements in the it came. stemming. The details of commercial gas stimu­ To obtain further information we have lation will vary from field to field, de­ proposed the following additional experi­ pending on the gas-reservoir character­ ments: istics and operating conditions. Any • Measurement of chimney connec­ specific concept must be based on maxi­ tions with tracers; mizing the gas production-to-cost ratio • Early gas-sample and chimney- and return on investment—consistent pressure measurements; with safe and environmentally acceptable • A postshot hole for measuring operating procedures. chimney radius, the effects of simultaneous detonation, and the CURRENTLY PROPOSED JOINT reservoir pressure gradient. INDU STRY -GOV ERNMENT EXPERIMENTS The Rio Blanco experiment is in an advanced stage of preparation and is Two experiments sponsored jointly by currently scheduled for execution during industry and government have been pro­ the first quarter of Fiscal Year 1973. posed that embody the multiple explosive concept. We briefly summarize them Wagon Wheel Proposal here. The El Paso Natural Gas Company has proposed the Wagon Wheel experiment. 14 Rio Blanco Proposal In the initial planning phase considerable The CER Geonuclear Corporation has effort was devoted to predicting the proposed a joint governmenVindustry cavity size and the crushed and shear IS fracture radii shown in Fig. 4. 15 Note experiment called Rio Blanco. Fig­ the small chimney size predicted at the ure 3 shows the cross section of this chosen site, where the gas bearing for­ experiment. Three explosives, each mation is about 3000 ft thick. For eventual with a nominal yield of 30 kt, are planned economic commercial production to be to be fired simultaneously at depths be­ tween 5700 and 6600 ft. achieved, a way must be found to fracture The company has proposed the follow­ through the entire gas-producing interval ing set of measurements that would con­ with a minimum number of explosives.

-11- • Gas flow from each chimney with tracers; • Seismic motion measurements; • Radioactivity measurements in the 5400r- gas. The proposed LLL add-ons are to meas­ ure and interpret the following: • Dynamic shock effects; e Early chimney pressures; • Chimney radius, chimney inter­ connections, and the fracture distribution caused by sequential firing; • Reservoir pressure gradient.

• Shear fracture to 220 ft

- Apical void 50% of original cavity volume

Radius of maximum fracture 441 ft i

6800 "- ;^1^V!,

J \

Fig. 3. Cross section of the Rio Blanco experiment. The dashed lines show the proposed postshot fracture and pressure monitor­ ing hole.

Therefore, it is proposed to use five 100-kt explosives fired sequentially. Figure 5 shows the conceptual design of the Wagon Wheel experiment. The measurements proposed by El Paso ^-Crushed to 123 ft Natural Gas are: • Determination of preshot reservoir • Civity radius 88 ft properties; • Gas production through the emplace­ ment hole; Fig. 4. Predicted result of a 100-kt ex­ plosion at a depth of 10,000 ft • Calculation of the fracture zone; in Wagon Wheel rock.

-12- made by C. H. Atkinson of the Bureau of Proposed 16 dynamic Mines. The regions presently judged nsrrumentation to be most suitable are the basins of the 9,000 Rocky Mountain states shown in Fig. 6. Table 2 gives an evaluation of the four Proposed basins. Atkinson estimated that only 20% postshor fracture of the potentially productive area may 10,000 and pressure monitoring holes actually turn out to be amenable to gas I stimulation. For these areas he further estimated that 40% of the total sand oa. thickness contains recoverable gas and that in 20 yr of production 50% of the gas could be removed by use of nuclear stim­ 11,000 ulation. These estimates led him to con­ clude that the successful use of nuclear stimulation could make available about 317 Tcf of gas from these four major Fig.12,00 5. 0Cros s section of the Wagon Wheel experiment. Rocky Mountain basins. It should be pointed out that it is This experiment is planned for Fiscal difficult to make such an estimate because Year 1974. of the very limited data available, and this figure should be taken as a rough POTENTIAL FOR GAS STIMULATION approximation. More recent information seems to indicate that the Green River An assessment of the areas that may Basin may be overestimated, while the be suitable for gas stimulation has been Piceance Basin may be underestimated.

Table 2. Estimated increase In reserves of natural gas assuming the effective use of nuclear explosives.3 A real Increased extent with Assumed Number Total recovery productive productive of known sand Productive using nuclear potential area gas-bearing thickness thickness explosives Basin (mi2) formations (ft) (ft) (Tcf)

Uinta 8,900 1800 4 1700 680 61 Piceance 3,900 800 4 1200 480 19 Green River 19,000 4000 7 2500 1000 199 San Juan 10,600 2000 3 1100 440 38 317 Assumes that 20% of the total area will be productive, that 40% of total sand thick­ ness contains recoverable gas, and that 50% of the gas will be recovered in 20 yr. The large Paradox Basin is too sparsely developed to permit a reasonable evaluation.

-13- _- "V ~-r i

IDAHO WYOMING • Casper

Cheyenne •

COLORADO

NEVADA ; • Denver Project Rio Blanco

Project Rulison rj Project Gasbuggy

* Albuquerque

ARIZONA NEW MEXICO I < • Phoenix

J i El Paso

Fig. 6. Low-permeability natural gas basins of the Rocky Mountain states. These basins contain reservoirs thick enough to be considered for nuclear stimulation.

-14- A more accurate estimate of the gas to conclusive formation tests. The potentially available in these regions is proved reserves in the lower 48 states now in preparation as a part of the National declined in 1970 from 275 to 264 Tcf Gas Survey being conducted by the Federal because the production of 22 Tcf was Power Commission. greater than the additions to reserves of 11 Tcf. The large 1970 addition to U.S. RELATIONSHIP OF NUCLEAR proved reserves of 26 Tcf in Alaska wili STIMULATED GAS TO PROVED . . -,,_,.„,, RESERVES AND POTENTIAL available to U. S. consumers until SUPPLY a gas pipeline is constructed from the North Slope. This gas is far from the Table 3 summarizes the Nation's markets in the contiguous 48 states and proved reserves and potential gas will require substantial investment to 18 supply during the last year and, for bring it to market. A pipeline to Chicago comparison, the supply that nuclear would cost about $2 billion.2 stimulation could make available. Proved The potential supply is the prospective reserves consist of gas that can be pro- quantity of gas yet to be found and proved duced in the coming years from gas wells by wells that may be drilled in the future that are producing or have been subject under assumed conditions of adequate, Tables. Gas reserves, production, and supply (in Tcf),

Reserves, Production, and Additions (1970) Proved recoverable reserves as of December 31, 1969 275 Additions during 1970 (not including Alaska) 11 Less: Production during 1970 (22) Proved recoverable reserves as of December 31, 1970 (lower 48 states) 264 Alaskan additions during 1970 26 Total proved U.S. reserves as of December 31, 1970 290

Estimated Potential Supplya Contiguous 48 states: Onshore Offshore Total Probable 179 39 218 Possible 227 99 326 Speculative 207 100 307 Subtotal 613 238 851 Alaska: _321 Total U.S. potential supply: 1178

Estimated Additional Supply Through Stimulation by Nuclear Explosives 317

Assuming existing economic and operating conditions.

-15- but reasonable, prices and normal im­ compare this volume with the 851 Tcf of provements in technology. If a funda­ potential conventional supply in the con­ mental change in economics or technology tiguous 48 states. Since a fundamental occurs, estimates of potential would be change in technology is required to make changed. the 317 Tcf of gas available, by defini­ Since the 317 Tcf of gas in tight for­ tion it has not been included in the mations are located in the contiguous proved reserves or estimated potential 48 states, it would appear proper to supply.

Gas Production from Nuclear Stimulated Wells

TECHNICAL FEASIBILITY pared with 8 years' production cf about 70 MMcf in the nearest conventional well. The most relevant data applicable to Nuclear explosions in other types of the gas-stimulation concept come from rocks and at greater burst depths can be the two nuclear gas-stimulation experi­ expected to fracture differently. In ments, Gasbuggy and Rulison. Gasbuggy Rulison, a joint Government/Austral Oil was a joint Government/El Paso Natural Company experiment, a 43-kt nuclear Gas Company experiment in which a explosive was detonated in September 29-kt explosive was fired on December 10, 1969 at a depth of 8427 ft in the Piceance 20 1967, at a depth of 4240 ft in the San Juan Basin in Colorado. Figure 9 shows an 19 Basin of New Mexico. Past production interpretation of the Rulison fracture data and analyses of coras were used to system; Fig. 8 compares the first 9 select the Gasbuggy site. Permeability months' production from the Rulison well measurements made on the cores gave with almost 8 years' production from the 0.14 millidarcy (md), but preshot pro­ nearest conventional well. Thus, both duction and laboratory measurements Gasbuggy and Rulison have proved ex - made under lithostatic overburden pres­ perimentally that nuclear stimulation can sures indicated an in situ permeability of increase gas production dramatically. about 0.010 md. Postshot drilling and production have GAS FLOW ANALYSES OF NUCLEAR yielded data on which the fracture inter­ STIMULATED WELLS pretation given in Fig. 7 is based. Extensive computational simulations Explosion-produced iractures were ob­ of the pressure and gas flow results of served as far as 700 ft from the shot Gasbuggy and of Rulison have been point, but basic matrix fracturing appeared made.11'21"24 to occur out to about 280 ft from the shot The Rulison flow analysis given by point (about 3i cavity radii). The gas was Montan (see Fig. 10) serves as an produced by reentering the emplacement example. Analysis of the well performance hole; Fig. 8 presents the production data. was made by fitting a simple model of the In 17 months, 280 million ft (MMcf) were chimney, gas sands, and explosively created produced. This number should be corn- fracturing to the two experimentally

-16- Fig. 7. Postshot cross section of the Gasbuggy experiment.

400, r T n I ' T GASBUGGY RULISON

Fig. 8. Gas production from the Gasbuggy and Rulison experiments. -17- Emplacement Reentry 600 ft Exploration

500 ft Cable break

400 ft

300 ft Fluid loss

T3 0) 200 ft

'a

T3 II 100ft

Oft I- Q-t

a* in -100 ft R = 76 ft c ^-D.O.B. = 8427 ft- Yield = 43 kt ^F^^^\i^M^-'^^mB^2L

-200 ft ±£±^mmjk

ra Gas sands LEGEND

Shales

Fig. 9. Postshot cross section of the Rulison experiment. R = cavitv radius; D.O.B. = depth of burial. c

-18- i—r i r ~X_ 3000 40

30 -

I 20 £ 2000 10

IS1»»>? 0

Distance from shot point — cavity radii I 1000 • Measured gas pressures

Calculated pressure

J L J L J I I L 1 15 1 15 1 15 1 15 1 15 1 15 1 15 1 15 1 15 Oct Nov Dec Jan Feb Mar Apr May Jun

Fig. 10. Gas flow from the Rulison experiment. The data cover the period from the time of the shot (September 1969) to June 15, 1970. The formation pressure is 3200 psia. The parameters assumed were:

Table 4. Assumed formation properties and nuclear well characteristics.

Reservoir properties Green River Basin Piceance Basin Reservoir thickness (ft) 2,400 2,000 Depth to midpoint (ft) 11,000 6,200 Effective in situ permeability (pd) 5 and 10 10 and 40 Specific gravity of gas 0.6 0.6 Temperature of formation (T) 200 200 Gas-filled porosity (%) 4 4 and 5 Gas-field pressure (initial) (psi) 6,000 3,000 Bottom-hole pressure during production (psi) 750 750 Gas in place per section per gross ft of height (MMcf) 70 20 Gas in place per section (Bcf) 170 100 Well spacing (wells/mi ) 1 1 20-yr gas production (Bcf) 21 - 35 14 - 31

Nuclear characteristics Number of explosives 3 or 4 3 Yield per explosive (k.t) 100 100 Cavity radius (ft) 88 98

20- a radius of 350 ft and extending 385 ft We made similar calculations for gas above the shot point and 220 ft below. To production from a well in the Piceance stimulate a 2400-ft thick section, four Basin. In this case we considered that such explosives would be required (see at the shallower depth of burial the larger Table 4). The calculated gas production, chimneys from three 100-kt explosives using permeabilities of 5 and 10 /ud, is would be sufficient to fracture the 2200-ft shown in Fig. 11. interval. Figure 12 presents cumulative production from a typical Piceance Basin well using permeabilities of 20 and 40 \i& 1 1 1 with three 100-kt explosives. o- ~ 30 T0^d-> - 1

t o ^^ productio n - o lativ e - /^^ \-5jid Cum u

3 f 1 1 1 10 15 20 Time — yr

Fig. 11. Calculated production from a gas reservoir in the Green River Basin stimulated by four 100-kt nuclear explosives. Curves are shown for two different permeabilities of the undisturbed formation. Fig. 12. Calculated production from a gas reservoir in the Piceance Basin stimulated by three In addition, we considered a case in 100-kt nuclear explosives. which more extensive fracturing in the Curves are shown for two different permeabilities of the vertical direction was assumed. Such undisturbed formation. extensive fracturing may result when the shock wave is reflected from the chimneys COMPARISON WITH CONVENTIONAL and fracture systems of earlier shots, WELLS IN THE SAME REGION as would be the case in sequential firing. Information provided by the Austral With a larger fracture system, it would Oil Company indicates that for several be possible to stimulate the entire 2400-ft conventional gas wells located in the section with only three 100-kt explosives. Rulison gas field the average projected The amount of gas produced would be the 20-yr cumulative production will be same as for the four 100-kt explosives, 0.26 Bcf per well. These wells cost but the cost would be less by one explo­ approximately $200,000 to $300,000; sive if such effects are observed. taking the lower cost we find that the

-21- required investment was at least $7 50,000 teams will be assembled whose capabilities per billion cubic feet of gas. Two addi­ could rise to a level of constructing 30 to tional wells that have been treated by 40 wells per year. Such a rate of firing modern hydrofracturing methods are would not be greatly different from the projected to have a 20-yr production announced rate of 39 nuclear events con­ averaging 0.4 Bcf. Using a conservative ducted during Fiscal Year 1970 at the cost of $300,000 for these wells leads to Nevada Test Site. It is envisioned that the same investment requirement—about two teams would operate in the Green $750,000 per billion cubic feet. By com­ River Basin, one building up to a con­ parison, an investment of $2.41 million struction level of 30 wells per year and in a Piceance Basin nuclear stimulated one to 40; a third team would build up to well is projected to result in a 20-yr 30 wells per year in the Piceance Basin. cumulative production between 14 and Table 5 gives a possible schedule for 31 Bcf—a unit cost of $78,000 to $172,000 commercial development, together with per billion cubic feet. the required number of explosives per Therefore, it appears that the average year. required investment in nuclear stimulated Using the annual gas production rates wells would be between one-fourth and for the Green River and Piceance wells one-ninth as large as in conventional wells with permeabilities of 10 wd and 40 jid, for the same total production from these respectively, as representative of well tight formations. productivities for'these regions, we calculated annual production rates for POSSIBLE SCHEDULE FOR COM­ total gas from the Green River and MERCIAL PRODUCTION OF GAS Piceance Basins. These are shown in BY NUCLEAR STIMULATION Fig. 13 and Table 6. No allowance was A 5-yr research and development pro­ made for reduced production due to field gram remains to be completed before full- use; in practice a few percent reduction scale industrial field development can would probably occur. begin. Details are presented beginning Although the calculations indicate that on page 46. The successful execution of in 20 yr only 20% of the Green River and Rio Blanco and Wagon Wheel would be 31% of the Piceance gas originally in place followed by a pe iod of production testing will be produced per well, for simplicity and evaluation. A group of three or five the assumption is made here that the wells pilot development wells in each basin have a 20-yr iife, (This assumption may might follow about 2 yr later, and upon have some validity because of the lenticular successful completion and evaluation of nature of the gas-bearing sands, which these wells full-scale commercial devel­ inhibits communication with the outlying opment could begin, perhaps as early as areas. However, there is no present data 1977 in the Piceance Basin. on this topic.) On this basis the total pro­ We assume here that industrial drilling, duction rate of nuclear stimulated gas field construction, and explosive firing would rise from 85 Bcf in 1976 to 2.5 Tcf

-22- Table 5. Possible commercial production plan for nuclear-stimulated gas wells. Fiscal Year 1977 1978 1979 1980 1981 1982 1983 Number of wells detonated (per year) Green River Basin A — 10 20 30 40 40 40 Green River Basin B — — 10 20 30 30 30 Piceance Basin 20 20 30 30 30 30 30 Total 20 30 60 80 100 100 100 Number of explosives required (per year) 60 100 210 290 370 370 370

Fig. 13. Calculated annual gas production rates from the Green River and Piceance Basins.

-23- Table 6. Proposed schedule of commercial gas production by nuclear stimulation.

Plceancc Basin Green River Basin A Green River Basin B Total First-year Total First-year Total First-year Total First-year Total Wells in gas gas Wells in gas gas Wells in gas gas Wells in gas gas Year production (Bct/yr) (Bcr/yr) production (Bcf/yrl (Bcl/yr) production (Bcf/yr) (Bcf/yr) production (Bd/yr) (Bcf/yr)

1077 20 85 85 20 85 OS 1978 40 85 130 10 48 4S 50 133 178 1979 70 127 212 30 97 121 10 48 48 110 272 381 1080 100 127 272 60 145 214 30 97 121 190 369 607 1981 130 127 327 100 193 326 60 145 214 290 465 867 1982 160 378 140 193 409 90 145 289 390 465 1076 J083 190 427 180 193 485 120 145 337 490 1249 1984 220 474 220 193 558 150 145 392 590 1424 !985 250 520 260 626 180 444 690 1500 19SS 280 583 300 693 210 494 790 1750 1987 310 605 340 7 59 240 543 890 1906 1988 340 647 380 820 270 591 99u 205U 19B9 370 884 420 881 300 637 1090 2202 1090 400 720 460 940 330 682 1190 2342 1991 430 758 SCO 997 360 725 1290 241)0 1992 460 792 540 1054 390 767 1390 2513 1993 400 824 580 1108 420 609 1490 2741 1E-84 520 USD 620 1161 450 849 1590 2860 !995 550 886 660 1215 480 888 1690 2988 1906 58D 918 700 1Z66 510 927 1790 3111 1097 590 930 740 1316 540 965 1870 3211 1008 GOO 938 770 1353 570 1002 1940 3293 1099 600 03B 790 1378 580 1026 I960 3342 2000 800 938 800 1392 600 1038 2000 3368 2001 2002 2003 2004 2005 600 127 938 800 193 1392 600 145 1038 2000 465 3368

in 1990 and reach steady state at 3.4 Tcf of total reserves is recoverable by nuclear in the year 2000. stimulation, it would take about 80 yr at Depending on the total areas available the above rate to recover it all. Thus, it for development in the two basins, this should be appreciated that nuclear stimula­ rate might continue for many years. If it tion can make an appreciable and long- lasting is proved valid that an estimated 300 Tcf contribution to the nation' s gas supply.

Economics of Gas Production by Nuclear Stimulation

ESTIMATED COST OF COMMERCIAL made for problems encountered in drilling GAS STIMULATION the emplacement holes and for failure of Table 7 summarizes the estimated l?s> of the nuclear explosives. Since it costs in 1976 of constructing a nuclear cannot be predicted which explosive in an stimulated well as part of a field develop­ array might fail, making removal of the ment effort in each of the two basins, gas below much more difficult and expensive, assuming the use of three 100-kt explo­ we have assumed 2% of the gas would be lost. sives in the Piceance wells and four in the Construction costs were inflated from Green River wells. Allowance has been 1971 costs at 5i% per year; the nuclear

-24- Table 7. Estimated costs per well for commercial gas stimulation (thousands of 1976 dollars).3 Piceance Green River Basinb Basinc Emplacement hole Includes site access, grading and a 10-3/4-in.-o. d. cased emplacement hole 7000 ft deep in Piceance Basin and 12,000 ft deep in Green River Basin 520 900 Allowance for drilling problems in development of field (unable to complete 1 of 6 emplacement holes) 90 150 Detonation service manpower Includes technical personnel to supervise explosive emplacement and stemming and to set up and operate firing equipment; based on a field- development rate of 1 well/mo 40 40 Explosive emplacement and stemming Includes equipment and personnel to etnplace and stem explosives; includes cost of all downhole hardware and stemming material 190 210 Reentry and completion Includes equipment and personnel to reenter emplacement well and wellhead hardware to complete well for production 60 70 Safety program Includes personnel to evaluate hazards and perform those activities necessary to ensure health and safety of general public and project personnel; includes equipment to monitor and document radioactivities daring production; based on a field-development rate of 1 well/mo 130 130 Subtotal without explosives 1030 1500 Nuclear explosives (AEC-announced charge for 100-kt) Includes required number of complete explosives with provision for sequential firing; includes temperature and pressure protection to 350°F and 10,000 psi and all firing components; 2% of gas subtracted as penalty for 99% explosive reliability 1380 1840 Total estimated cost per nuclear-stimulated well with allowance for lost holes in field development 2410 3340

aCosts inflated from 1971 to 1976 at 5.5% per year. Three 100-kt explosives per well. cFour 100-kt explosives per well.

-25- explosive cost was based on the schedule SINGLE-WELL REVENUE ESTIMATES of charges recommended by the AEC for use in evaluating potential Plowshare Table 8 summarizes the revenue and applications. 29 As summarized in Table 7, expenses from a single nuclear gas well we have estimated the costs per well as in the Green River Basin over a 20-yr $2,410,000 and $3,340,000 for the Vvo period. Similar revenue calculations have basins, respectively. The cost of the been made for production from the Piceance Green River well with one fewer explosive Basin well. In this analysis we have ob­ would be reduced by $460,000. tained gross revenue by deducting 12.5% The actual number of explosives re­ of the gross production for royalties paid, quired, ruid therefore the total costs, will principally to the federal government that depend on which assumption regarding the owns the land, and have used a wellhead extent of fracturing from multiple explo­ gas price of 40f /Mcf for the remaining sions is supported by experience. It gas. Future net revenue was obtained by should be noted that these costs do not deducting state and local taxes (consisting include the cost of acquiring or proving of severance and ad valorem taxes in out the lease nor the expenses incurred Wyoming at 6.5% and in Colorado at 12.5%), in collecting and transporting the gas to a administration expenses at 3%, and transmission system. operating expenses at $500 per month per

Table 8. Economic analysis for single-well development in the Green River Basin. This assumes a permeability of 10 /id, a wellhead gas price of 40f /Mcf, and the use of three or four 100-kt explosives.

Production (MMcf) Revenue and expenses (thousands of dollars) Net General and Lease operating (87.5% Gross Severance Ad valorem administration expense Future net Year Gross of gross) revenue tax (1%) tax (5.551) expense (3%) ($500/ month) revenue

I 4837 4232 1693 17 93 51 G 1S2G 2 2413 2111 844 8 46 25 6 758 3 2110 1846 738 7 41 22 6 G62 4 1945 1702 581 7 37 20 G 610 5 1837 1607 643 6 35 19 6 576 6 1735 1536 614 6 34 18 6 550 7 1692 1480 592 6 33 18 G 530 8 1637 1432 573 6 32 17 6 512 0 1589 1391 556 C 31 17 6 497 10 1546 1352 541 5 30 16 6 184 11 1505 1317 527 5 29 16 6 471 12 1467 1284 514 5 28 IS G 459 13 1432 1253 501 5 28 IS 6 448 14 1303 1224 489 5 27 15 G 437 IS 1366 1195 478 5 2G 14 G 427 16 1335 1168 1G7 5 ?6 14 6 417 17 1306 1142 457 5 25 14 G 408 18 1277 mo 447 4 25 13 G 399 19 1250 1094 437 4 24 13 G 390 20 1224 1071 428 J 24 13 6 382

-26- im * N.it:

well from the gross revenue. The last development expenses because their impact column in Table 8 gives the future net on the profitability of a development varies revenue for each year. from company to company. As an example Figures 14 and 15 show the discounted of the effect of taxes on profitability, in cash flow rates of return on these invest­ ments as a function of gas sales price 1 1 1 - y- i -y (before depletion, depreciation, and 35 federal income tax) for the respective permeabilities and numbers of explosives 30 - 40 (id-\ / / appropriate to the wells in the two basins. One can see that at a gas sales price of 25 / Uoud- 4 Of /Mcf the rate of return on investment 1 c in a Piceance Basin well varies from 7.4 |20 to 28,5%, depending on the permeability; the rate of return on investment in a t> £ 15 ^r — Green River Basin well varies from 10.5 a to 27.9%, depending on permeability and 10 - f\ _ the required number of explosives. V-10pd The rates of return in these figures do 5 not include items such as federal income tax, depletion, depreciation, and intangible 0 1 i 1 1 1 10 20 30 40 50 60 70 3 3 Gos soles price — cents/10 ft 35 Fig. 15. Discounted rate of return of a Piceance Basin gas well stim­ 30 Three ulated with three 100-kt explo­ explosives sives (1976 dollars). Curves are shown for three different 25 perm eabilities.

20 Table 9 we present a possible summary 10 ud of the cash flow derived from the revenue 15 of Table 8 with 20% of the well-development cost capitalized and straight-line- 10 depreciated over a 20-yr period, a 22% gross revenue depletion allowed, and a 48% federal income tax rate applied. De­ preciation and depletion are added back to 10 income after tax to obtain the cash flow. 3 3 Gas sales price — cents/10 ft The remaining 80% of the well cost is treated as an expense and deducted from Fig. ?4. Discounted rate of return of a nuclear-stimulated gas well other taxable income of the company. in the Green River Basin for About 60 to 70% of conventional-well costs two different permeabilities (1976 dollars). qualify for treatment as an intangible

27- expense, and the explosive charges would COST COMPARISONS OF ALTERNATE appear to qualify in this category. The GAS SUPPLIES effect would be to increase this fraction We now are in a position to compare to at least 80%. The resulting tax credit some of the economic factors related to of $1.28 million then gives a net invest­ alternative methods of obtaining increased ment cost for well development of 52.06 gas supplies. To place the methods on million. Discounting the tabulated rev­ an equivalent basis for comparison, we enue cash flow indicates a rare of re­ have estimated the time and relative in­ turn of 25%. This compares closely vestment costs required to develop the with the 22. 5% rate of return (before more probable sources so as to attain an federal income taxes) indicated in Fig. additional gas supply capability of 1 Tcf/yr 14 for the same well with four explo­ (see Table 10). The table also indicates sives at a permeability of 10 fi6. The the approximate magnitudes of current or same type of calculation for all the currently proposed investments, the likely possible wells shown in Figs 14 and 15 ranges of gas sales prices, and the re­ gives rates of return after depletion search and development funding required and federal income taxes about 2 to 3% (if any) to bring these sources to com­ higher than the returns before taxes. mercial production. This indicates that income tax, depre­ Table 10 shows that gas produced from ciation, depletion, and tax credits ef nuclear-stimulated wells has the po­ effectively cancel insofar as the rate tential of being more economic than all of return is concerned. other sources except conventional

Table 9, Economic analysis for single-well development in the Green River Basin, including federal income tax, depreciation, and depletion (thousands of dollars). This assumes a permeability of 10 j/d, a wellhead gas price of 40£ /Mcf, and four 100-kt explosives.

Less Less Add Future Less depletion Net federal Add back Gross net depreciation Taxable allowance taxable income tax ."jack depletion Cash ear revenues revenue (20T. Hi cost) inconle (2» of gross) inconie (48%) Income depreciation allowance flovv I 1693 1526 33 1493 372 1120 538 383 33 372 988 2 844 758 33 725 186 539 239 350 33 186 499 3 738 662 33 625 162 466 224 243 33 162 430 4 681 61C 33 577 150 437 205 222 33 150 405 5 643 576 33 542 141 401 192 309 33 141 383 6 614 550 33 517 135 281 183 198 33 135 367 7 532 530 33 496 130 3GK 176 190 33 130 354 B 573 512 33 479 126 353 169 184 35 126 343 2 556 497 33 464 122 342 164 178 33 122 333 10 54! 484 33 450 119 331 159 172 33 119 325 11 52. 471 33 437 116 321 154 1*7 33 116 31C 12 514 459 33 425 113 312 150 162 33 113 3D" 13 501 448 33 414 no 304 146 •58 3.. no 30:> 14 483 437 33 404 108 256 142 154 33 108 295 15 478 427 33 393 105 288 138 :ao 33 105 288 16 467 417 33 383 103 281 135 146 33 :03 282 17 457 408 33 374 101 274 131 142 33 101 27 G IO 447 399 33 365 98 36TI 128 139 33 93 270 i? 437 350 33 357 'J6 260 125 135 33 96 265 20 428 302 33 348 94 254 123 132 33 94 260

-28- Table 10. Costs for alternative gas supplies.

Approximate Approximate Approxim ale Current RcJJ Total time scale curre.it or capital investment Gas Bales funding required (yr to reach proposed required to attain an price level R&D funding additional investment additional I Tcfjjr Call dollars (millions of (millions at 1 Tci/yr) (billions of dollars) (billions of dollars) per thejsard ft3) dollars per yr) dollars)

Conventional exploration Onshore 2-3 Q.16a 0,;.5-0.45d 6 Offshore 3-5 I.5-2.0C 0.30-0.65 0 *™ (Chicago) Alaska B-10f 0.2 ld +2.06 0.7 5-1.00* •Chicago)

Imports from Canadian Arctic 3-5< 0.2 5a + J1 0.75-I.0Qe (Chicago)

Liquefied 0.1-0.2f ri 11971-197 5) l natural Gas -3 0.68-1.00 0 Some Imports ~5 1.0/yr (Cast Coast) (iy-6-1980)

Synthetic eas Naphtha and 5-7^ -O.-KP 10 plants (§£150 million = l.oJ o.aa-i.eoJ 0 Same heavy-oil (at source) gasification Coal —,0-I5k 0.25m 10 plants L mines = 2.9U 0.70-1.00e 15 federal 300P gasification (at source) 30 industry

Nuclear stimulation 10 No commercial 300 ivells (5 S3,34 million = 1.0 G.4 federal investment 160 wells (2S2.44 million = 0.4 0.40-0.50 6.0 Industry 100-150 (1976 S) Total 1.4

Current one-time only funding.-3" Normal funding—based on costs of exploration for oil and gas as reported in Ref. 31. The costs far gas exploration were approximated by prorating the total costs for oil and gas exploration according to the costs of successful exploratory oil and gas wells. cThis figure was estimated 35 follows: (1) Divide the average U. S. total reserves (275 Tcf for 1969) by the total U.S. productive capacity (36.5 Tcf/yr in 1969) to obtain the average reserve lifetime capability (7.G yr in 1969); (2) divide this average lifetime into the average annual newly discovered additions to reserves (about 5.5 Tcf/yr from 1964 through 1970) to obtain the average change In productive capacity per year; (3) divide this number into the average total costs for gas exploration (see footnote b), which ranges from about SS90 million In 1965 to about S956 million in 1969) to get the costs per unit change In productive capacity per year. The average for the years 1965 through 1969 Is SI.3 billion. Reference 32. The price listed includes a transmission charge of 10-15^/Mcf. eReference 33. Reference 8, p. 31. *"For pipeline (Alaska only). cJormal funding level unknown. For ships, terminals, and storage facilities !Ref. 8, pp. 31 and 36). 'Reference 34. ^Reference 8. mRererence 35. "Reference 8, p. 54. pReference 36.

exploration in terms of required invest­ the time needed to produce commercially ment, gas sales price, and research worthwhile quantities. An expanded dis­ and development funding, and it is cussion of these topics is given in Ap­ competitive with the others in terms of pendix A.

Potential Markets and Delivery Schedule

Figure 16 shows the projected U.S. gas Fig. 16). Alternatively, this quantity of requirements by geographic region through gas could supply half of the projected in­ 1995, assuming no constraints on supply. crease in the Great Lakes area (Region 4). The production schedule we have proposed Figure 17 shows the projected State of would reach 3 Tcf/yr by 1995. This would California demand, the past production 37 equal the total projected increase in the and consumption in California, and our far western regions (8, 9, and 10 in projected production of nuclear stimulated

-29- .-NEW ENGLAND-REGION 1 1970 1250 75 _1 336 85 "150S 95 J 770 APPALACWA-REGIQN 2 1970 13908 75 '•~|5213 SS t 7225 95 ^H9B' SOUTHEAST-REGION 3 1668 A228 34S8 5431

GREAT LAKES-REGION 4 1970 " I 2970 75 ''~ |44S3 85 "^6507 95 I9S30 NORTHERN PLAINS-REGION 5 977 1179 14S9 1783 MID-CONTINENT-REGION 6 1563 11969 **"12668 "13435 GULF COAST-REGION 7 1SSSL TasM 85 ^Mg.W)7 95 ID ".345 ROCKY MOUNTAIN-REGION 8 1970 [535 75 1652 85 "1812 95 J 1031 PACIFIC SOUTHWEfT-REGION 9 2615 3360 3818 4609

PACIFIC NORTHWEST-REGION 10

1— 1 1 1 —1 1—1— 2.000 4.000 6.000 8.000 10,000 12.000 14.000 16.000 'C.OOti 20.000 BILLIONS OF CUBIC FEET

Fig. 16. Future U. S. gas requirements by region. The 1970 data are the actual requirements; the 1975 data are estimates; the 1985 and 1995 data are projections. (Reproduced from Ref. 7 by permission of the Future Require­ ments Agency.)

-30- 1 /I Actual Projected

Total consumption -

Inter, jptible industrial and other

Electric J power

- Gas produced in California • Nuclear stimulated total

Residential, commercial, and Firm industrial

I

I 1965 1970 1975 5980 1985 1990 1995 2000 Year

Fig. 17. State of California gas consumption and production. gas. One can sec that by 1995 we could ifornia would be provided to start de­ .supply 80% of the total California de­ liveries in 1077. (We estimated pipe­ mand. line capacities from figures given by Table 11 shows one possible sched­ Coates, pipeline costs on the basis ule fcr delivery of the gas to California. of average costs given by O' Donnell, " A 36-in.-diam pipeline to Southern Cal­ and compression station costs as 20% -31- Table 11. Possible schedule and costs for delivery of nuclear-stimulated gas to Calif ornia. 1972- 1978- 1980- 1982- 1985- 1991- 1977 1979 1981 1984 1990 2000 Additional number of wells constructed Piceance Basin 20 so 60 90 180 3C0 Green River Basin 40 120 210 420 700 Well cost increment (millions of dollars) 48 254 545 917 1834 3063 Pipeline characteristics Size 36 in. 48 in. — 48 in. 48 in. — Capacity 0.5 Tcf 1 Tcf — 1 Tcf 1 Tcf _ Market Calif. Calif. — Calif. Illinois — Pipeline cost increment (millions of dollars) 230 360 — 360 520 — Annual gas production at end cf period (Tcf/yr) 0.38 0.87 1.42 2.3 3.4 Total cost increment (millions of dollars) 278 664 545 1277 2354 3063

of pipeline costs.) This size of pipe­ 1 Tcf/yr might be directed to the Great line could handle up to 0.5 Tcf/yr. Lakes region. Because of the relatively assured sup­ Interestingly, the capital investment ply, 48-in. pipelines capable of deliver­ initially required for pipelines could be ing I Tcf/yr would be added as re­ larger than that for the nuclear stimulated quired to handle the expected increase wells. Amortization of these pipelines, in total production rate. If the Cali­ however, would not affect the wellhead fornia market were being adequately gas price; the pipeline costs would be supplied by 1083 from supplemental reflected in the price of gas delivered to sources, a pipeline to take the final the marketing region.

Radioactivity in the Gas

Based on the above plan for gas delivery, from a 100-kt Diamond explosive in a gas we have estimated the future dose commit­ well environment. ment to the consuming population result­ Although gas was fla»*ad from Gasbuggy ing from use of nuclear-stimulated gas. and Rulison and will be flared from Rio Models based on data from Gasbuggy Blanco, Wagon Wheel, and probably and Rulison have been used to calculate several future experiments, we assume gas composition. Tritium production by that well and field properties will have the explosives is based on that expected been established in the experimental phase

-32- and that no flaring is expected for com­ radionuclide concentrations in the gas from mercial field development. the two basins will .result from differences 40 41 in rock composition, depth, and tempera­ Data from Gcsbuggy and Rulison ture, as well as from the fewer explosives identified tritium, krypton-85, and required in a Piceunce Basin well. Due carbon-14 as the only radionuclides of to the high early production rates, almost significance in the gas vis a vis radiation all of the contaminants in the gas will be exposure to potential consumers of stimu­ removed from the well by the end of the lated gas when sufficient time is allowed first year, and second-year average between detonation and production of the radionuclide concentrations will be about gas (at least 3 mo). All of the krypton-85 1/1000 of the first-year averages. was in the gas, whereas tritium was dis­ We will consider two alternative pro­ tributed among hydrogen-bearing species, posals for the delivery and use of the gas principally water and natural gas, with and the estimated population dose from only a small fraction available to the gas each: (Da uniform mixing model and (about 5% for Gasbuggy and about 10% for (2) separate use of first-year gas from Rulison). Carbon-14 is produced in such new wells for power generation. small quantities that its contribution to California is the assumed market area the potential dose to man is very small for the stimulated gas, and wc assume compared with that of tritium, even when that the ORNL dose model for consumption 42 the Diamond explosive, whose tritium of stimulated gas in Los Angeles is production is minimal, is used. applicable for gas use throughout the Table 12 gives the expected tritium and state. The estimated fuiurc population was krypton~85 concentrations in the gas based on 1070 estimates of 20 million (after water and carbon dioxide removal) as annual average concentrations for the The final 1970 population figures are expected rate of production from wells in 19,953434 for the state and 7,032,075 for Los Angeles County. the two basins. Small differences in

Table 12. Average radionuclide concentrations in produced gas (after carbon dioxide and water removal). No. of 100-kt __ explosives Annual average concentration (pCi/cm ) Basin per well Year Tritium* Krypton-85

Green River 4 1 llb 71 2 0.015b 0.1 Piceance 3 1 <8C 60 2 <0.004C 0.02

Assumes negligible exchange of tritium from water to methane aftsr the start of production. bFrom Ref. I. cBased on a <2000-Ci tritium residual for a 100-kt Diamond explosive in a gas well environment.

-33- for California and 7 million for Los would be less than 0.64 mrem/yr in 1981 Angeles and a growth rate of 1.5%/yr. and the highest maximum dose would be Dose equivalents are calculated for sub­ less than 1.0 mrem/yr. For tho separate mersion, inhalation, and skin absorption - pipeline model, in which the first-year only. Contributions from food chains are gas is delivered to power plants, the expected to be small relative to these average dose to individuals would be less direct modes of exposure. Whole-body than 0.11 mrem/yr and the maximum dose dose calculations for krypton-85 are based would be less than 2.1 mrem/yr. Thus, on Hendrickson's model. 43 the separate pipeline model results in a Figure 17 shows the -stimulated gas lower average individual dose but slightly supply from the proposed commercial increased maximum dose. However, as field development compared with the shown in Fig. 20, the population dose projected demand for California, and would be decreased from about 15,000 man- Fig. 13 shows the supply of first-year gas rem/yr to the 1500-2000 man-r™m/yr from new wells. Figures 18 and 19 show range. To keep exposures as low as the average and maximum radiation ex­ "practicable," this alternative may be posures to individuals (using upper-limit preferrable if the extra complexity of tritium concentrations) from these two handling the contaminated gas in a methods of gas delivery to the California separate pipeline does not represent an population, and Fig. 20 shows the popula- unreasonable cost. However, even the tion dose. A more detailed discussion of exposures resulting from the uniform these topics is given in Appendix B. These dilution model are a very small fraction figures do not include the possibly higher of the natural background. doses to the small number of individuals Table 13 summarizes the different using unvented gas heaters or appliances. possible tiuses to the California population As shown* for the uniform mixing model, from use of nuclear-stimulated gas and the highest average dose to individuals compares them with doses from natural

The contribution to dose from the ex­ products from the 10 Los Angeles power clusive power plant usage of stimulated plants using a computer model that con­ gas in Los Angeles was not considered in siders the frequency distribution of at­ Ref. 42. Therefore, in this report we mospheric stability categories as a func­ scaled (by the fraction of total gas usage tion of wind direction, the actual wind represented by power plant consumption) speeds associated with the different direc­ the average ground-level concentrations tions and stability categories, and the from AJI sources indicated by Barton effective plume height for each power etal. to obtain conservative estimates plant. He used 5 yr of data from four of the average dose to the population re­ weather stations in the vicinity of the sulting from only power plant use cf first- power plants. Preliminary results44 year gas from new wells. The maximum indicate that both the annual maximum dose to individuals downwind of power close to individuals and the average dose plants, however, was baseo on the peak to the population will be at least one order ground-level concentration of 100 cm3 of of magnitude lower than those indicated gas per cubic meter of air calculated by in Fig. 19. This appears to invalidate Barton etal.42 Recently, T. V. Crawford the conclusion stated above that the of this Laboratory carried out preliminary separate pipeline model would result in a calculations of the annual average ground- slightly increased maximum dose to level air concentrations of combustion individuals.

-34 1000

100

Maximum dose to individuals (downwind of large gas-burning 10 power plants)

3 Average dose to individuals

Direct exposure only Based on Los Angeles model for all heating and 0.1 appliances vented except range; does not include the dose contribution to the small number of individuals with unvented heating and appliances.

0.01 1976 1980 1984 1988 1992 1996 2000 Year

Fig. 18. California per-capita exposure from tritium and krypton-85 assuming uniform mixing of nuclear-stimulated gas with the total gas delivered to the state. 1000 i—'—r

-Natural background

100

10- -Maximum dose to individuals (downwind of power plants) I I I

I •Average dose to individuals

0.1

Direct exposure only Based on Los Aogeles model for atmospheric exposure scaled to power plant exclusive use of gas.

0.01 1976 1980 1984 1988 1992 1996 2000 Year

Fig. 19. Individual exposures in the vicinity of power plants from tritium and krypton-85 assuming separate power-plant use of first- year gas from new wells.

36- 10,000,0001 1 1 1 r- 1 r

- Natural background

1,000,000-

100,000 -Uniform mixing of stimulated gas with total gas I

10,000 -Power plant use of first-year gas from new wells

1,000 Direct exposure only Based on Los Angeles model; does not include the dose contribution to the small number of individuals with unvented heating and appliances.

1976 1980 1984 1988 1992 1996 2000 Year

Fig. 20. Upper-limit population exposure due to the use of nuclear-stimulated gas in California.

-37 Table 13. Radiacion exposure to population of California from various sources. 2000 1970 estimated 1970 individual 2000 estimated estimated exposure estimated individual population (mrem/yr) population exposure exposure exposure Source (mrem/yr av) (man-reni/yr) Av Max (man-rem/yr)

Natural background 114 2,300,000 114 — 3,500,000 All medical sources 98 2,000,000 160 — 5,200,000 Nuclear atmospheric tests 5 100,000 5 — 160,000 Nuclear power reactors 0.002 40 -0.2 — 6,030 Power-reactor fuel reprocessing 0.0008 16 0.2 — 6,000

Gas Stimulation General use of all gas <0.45 <0.7 <14,000 Power plant use of first-year gas <0.11 <2.1 <2,000 background and other man-made sources Tritium in the gas will be released of radiation_•- . . 45 at a rate of less than 0.14 MCi/yr af­ On a worldwide scale the long-lived ter the fourth year of production. This tritium and krypton-85 from nuclear-gas corresponds tG a contribution to the stimulation are of concern as contributors worldwide tritium inventory at steady to the general buildup of these radionu­ state of 2. 5 MCi, which would be about clides in the biosphere. Based on the 3 to 10% of the naturally produced above models for field development, the inventory from cosmic rays. We expect krypton-85 in the gas will be released at that tritiated water produced from the a steady rate of 0.85 MCi/yr after the stimulated wells (and removed from the fourth ye&r. Worldwide buildup of gas before it enters the pipeline) wilt krypton-85 from this source would be disposed of in a manner that per­ approach a steady state value of 13 MCi manently isoloates it from the biosphere by the end of this century. Assuming a by rctnjection underground. If it cannot uniform distribution in the atmosphere-, the be so disposed, the rate of tritium re­ whole-body dose to individuals worldwide lease could be about four times the mrem/yr. above rate. Environmental Impact

WELL CONSTRUCTION a nuclear-stimulated well are essentially no different from those of a conventional The permanent local environmental gas well. Power lines, access road.s, a effects resulting from the construction of leveled area for operation of the drill rig.

-38- mud pits to contain drilling mud, and gas For example, an estimate of $50,000 pipelines would be required. Items not has been made for the damage to be ex­ needed after completion of construction, pected as a result of the Rio Blanco ex- such as the mud pits, could be restored 47 to their initial condition. pertinent in Colorado. This estimate At the depihs of burial contemplated is primarily a result of architectural for the nuclear explosives, no surface damage (e.g.. plaster cracking, fallen subsidence or other permanent disturb­ bricks at residential and public structures). ance should occur. Figure 21 shows three examples of such minor damage experienced as a result of SEISMIC EFFECTS Ruiicon. Predetonation preventive mainte­ nance probably will reduce this cost. The principal limitation on the maxi­ Table 14 presents the Gasbuggy and mum size of nuclear explosive that can be Rulison seismic damage experience and used fee nuclear stimulation is due to the gives estimates of the expected costs for transient seismic shock immediately Rio Blanco. Wagon Wheel, and the com­ following the explosion. Based on the mercial Piceance and Green River Basin results from many underground nuclear wells. experiments, methods have been developed To minimize the number of days on for predicting the expected components of which local populations would be subject to this seismic nuisance, one possible ground motion: peak vector acceleration, 46 mode cf operation would be to construct a velocity, and displacement. These number of wells and detonate them all on methods take into consideration the effects the same day. Four detonation days per of source, transmission path, and year should suffice for the 30 or 40 wells- receiving-site geology. per-year size of field operations we have In addition, the experience from such postulated. damage to structures as h=»s been seen in Inconvenience to the public on shot days Hattissburg, Mississippi, from Salmon may require suitable compensation. How­ and in Mercury, Nevada, from many ex­ ever, the expected annual costs for seismic periments at NTS and in Meeker, Colorado, damage are small (ses Table 14). from Rulison provides a measure of cor­ relation between fhe expected ground SEISMIC AFTERSHOCKS motions and the degree of expected structural damage*. Underground nuclear explosions some­ In the relatively remote Piceance and times generate small aftershocks iti the Green River Basin locations, the number immediate vicinity. The specific mech­ of existing structures exposed to. such anisms for generation of these small damage will be low. Well sites will be earthquakes are not known, but they are constrained to those locations where the apparently related to residual stress repair cost of such minor damage as does changes produced by the explosion. occur will be an acceptable cost to the Rulison provided information on the operation. aftershock susc-.ptibility of an area that

-39- Fig. 21. Typical seismic damage from an underground nuclear explosion: cracking of masonry foundation (upper left), dislodged bricks (lower left), cracking of plaster (right).

Table 14. Seismic damage estimates.

Gasbigg? Kultsott Piceance Basin Green River Basin UctusD (actual* Rio Bianco commercial Wagon Wheel commercial

Number of Ke* 1900 300 •300 1350 1350 structure* (Si-15 mi> (0-23 mi) (0-20 mi) (0-40 mif susceptible 3000 to damage (2S-J0 mi) Number of 320 8S "5 Y 2 (for

Estimated S93.000 S3C.000 -S2S.00O $05,000 sso.ooo value of (paid) claims

Annual claim •sioo.ooo < =200.000 estimate for cosistercial operation H detoaat' Uays/yr)

-40- statistically has a low frequency of earth­ detonated in a region where high natural quakes. The U.S. Geological Suryey's stress had built up, might trigger an National Center for Earthquake Research earthquake with greater seismic energy and the National Oceanic and Atmospheric and greater hazard potential than the ex­ Administration's Earth Science Laboratory plosion itself. However, because Colorado both instrumented the Rulison area with and the Green River area of Wyoming are seismographs. not active seismic regions and have no Ambient seismic activity was monitored history of destructive earthquakes, we for several days before the detonation and do not believe that this will constitute a no earthquakes were detected. Many small risk. There is no realistic prospect of aftershocks were detected within a few prematurely setting off a major earth­ minutes after the detonation; all originated quake that might have been near the point within 3000 ft of the Rulison location. of natural occurrence. Further monitoring for 20 days at dis­ tances out to 60 mi indicated 27 seismic DISPOSAL OF RADIOACTIVITY IN events; of these, 14 were less than 60 mi THE CHIMNEY GAS from the Rulison emplacement well, but the largest had a body-wave magnitude of During the early stages of commercial 2.2. nuclear stimulation development there On the basis of such experience, we will be a need to test the gas productivity expect that each explosion in the 100-kt of test wells constructed in previously yield range will generate no more than a untested geological formations and loca­ few dozen such events, none having a tions. This will require flaring both of Bichter magnitude greater than 3 (com­ the gas that fills the chimney after the pared with a Richter magnitude 5h body detonation and some amount of the gas wave for each of the five detonations). that continues to flow into the chimney These will cease within a few hours. The from the surrounding formation as the total seismic energy released will be well is produced. substantially less than that from each Small amounts of radioactivity will be 100-kt explosion. The ground motion they released to the environment during this produce may be perceptible to an ob­ flaring operation. However, we believe server within a few t: iles of the detona­ the exposures resulting from such re­ tion, but probably not farther away. leases can be held to acceptable levels. They will present neither hazard nor As an example, the statements regarding identifiable impact on the environment. maximum exposures to man from flaring In connection with earlier underground of the gas during production testing of detonations, the argument has been Rio Blanco are quoted from the environ- raised that, while the innocuous small . . 48 aftershocks described above are the mental statement : expected effect, it is not impossible in "The calculations assume maxi­ principle that some future explosion, if mum radioactivity concentrations and a maximum rate of flaring.

-41- The possible resulting radiation The Pest method for disposal of this exposure to man from the produc­ water has yet to be determined. It is tion testing activity is found to be possible that the water could be reinjected a small fraction of the natural into the producing well, thereby isolating background radiation. While the it permanently underground in a location radiation exposure to man fro-n where it could not have access to aquifers. dry deposition is estimated to be The disposition of water containing a small fraction («1%) of the low levels of tritium will be a continuing natural annual background there aspect of nuclear stimulation field opera­ is the opinion held by some tions. The final choice of disposition scientists that any exposure methods will depend on interactions be­ above ar.nual background (jpprox-* tween costs and the government policy of imately 140 rnrem per year at practicable and minimal releases of the location of Rio Blanco) radioactivity to the environment. J49-51J should be avoided. Other scientists maintain that these GROUNDWATER EFFECTS radiation levels have no somatic, physiological or genetic effect Detailed hydrologic studies of each atall.^" local area selected for nuclear stimulation Once the potential productivity at a will be necessary in order to understand particular area is determined, flaring of the conceivable pathways by which radio­ gas should not be necessary for normal active contamination might enter the commercial operations. However, the groundwater and to assess the potential carbon dioxide and water vapor present hazards. Such as assessment has been in the gas must be separated from the 48 methane before it can be delivered to the made for Rio Blanco, While the condi­ pipeline. Natural gas from conventional tions will be different for each specific location, the Rio Blanco analysis may be wells is normally processed through taken as indicative of the environments to purificition facilities to remove these be expected in developing these basins. constituents, which are then harmlessly The U. S. Geological Survey has thor­ discharged to the environment. However, oughly studied the hydrology of the Piceance 35-50% of the tritium initially present in Creek Basin. The bottom of the lowest the chimney may be in the water vapor, and aquifer region containing mobile water is this water, after condensation and separa­ at least 3500 ft above the calculated top tion from the methane, could have a of the detonation-induced rock fractures. specific activity in the range of 0.02 to Therefore, no aquifer will have direct 0.05 ^Ci/ml. This is 20 to 50 times the communication with the explosion produced ICRP-accepted standard for potable water." chimney. Near the emplacement well, the water in this lowest aquifer (called *The current radiation protection guide­ the "B" aquifer) is sub-rotable, containing line value for tritiuci-containing water is 1000 pCi/ml, as established by the Federal about 3000 ppm of dissolved solids. Radiation Couiicil (now a part of the EPA). Water moves through the "B" aquifer at

-42- less than 1.2 ft per day. The nearest Thus it may be concluded that no con­ current-use point from this aquifer is tamination of the groundwater near tile 3.6 mi from the detonation site. If the Rio Bianco site is anticipated. Imme­ water were assumed to be flowing towards diately following the detonation, some this point, the radioactivity would take increase in turbidity may be experienced some 43 yr to arrive there, assuming also in water wells out to 10 mi due to shaking that it was first able to enter the aquifer. of the weli cores, but this should subside By that time, from radioactive decay alone in a few days. In addition, water wells and not assuming any dilution by uncon- and springs within 3 mi may show a slight tamirtjted water, the tritium concentration temporary increase in flow due to a rise would be less than 1% of the current radia­ in the piezometric surface. tion concentration guides for water. The potential individual dose that could be EFFECTS ON OTHER MINERAL accrued by drinking this water would be RESOURCES less than 1 mrem/yr. Concern has l>een expressed over the At the emplacement well, the 'x" possible deleterious effects of gas stimu­ aquifer lies between 880 and 1650 ft below lation detonations on other mineral for­ the surface. It is overlain by an aquitard mations mat might render them unmineable —a flow-restricting formation. Still by standard methods such as formation higher, between 245 and 845 ft below the fracturing or increases in water intrusion. surface, is the so-called "A" aquifer. For example, at the Rio Blanco site The quality of the water in the "A" aquifer the major mineral resources are oil shale is better; it contains only 640 ppm ot dis­ and sodium and aluminum-bearing min­ solved solids. If there were a small erals (nahcolite and dawsonite), located crack that ran from the cnimney to the at depths of 440 to 2300 ft. surface and radioactivity were to seep At a meeting of the Colorado Governor's up that crack, only 1% of the activity Advisory Committee on Project Rio Bianco, wou'd pass through the "B:' aquifer the Oil Shale Corporation (TOSCO), and on to the "A': aquifer. Water flow Superior Oil Corporation, and Wolf Ridge velocity in the "A" aquifer averages Minerals Company each expressed their less than 0.8 ft/day. The nearest well concern that the project would jeopardize tapping the "A" aquifer is about 6. 5 development of the oil shale and sodium mi from the emplacement well (but in minerals.S 3 Their concern is principally a direction that is almost perpendicular that the effect of the stress wave on the to the groundwater flow). Even assuming joints and the fractures in the Green River that the flow were towards this well, Formation might be such as to make min­ contaminated water would take 100 yr ing more difficult or perhaps impossible. (at current flow velocities) to reach They also stated that the mineral resources it. Thus, the tritium levels would have in the area are potentially more valuable decayed to far lower levels than those than the gas and that the possible loss of quoted above for the nearest use point in such large mineral resources is not worth the "B" aquifer. the risk.

-43- The possible mechanisms and extent of a criterion that no fault be closer than effects on the oil shale formations have 7000 ft may be reasonable for future 34 55 been studied in some detail. * These operations. included fracturing of the rock by the out­ This Laboratory has obtained consider­ going shock wave, the possibility of motion able experience relevant to potential mine induced on faults, the possibility of mine and tunnel damage in connection with damage, and the possible increase of nuclear detonations in or near tunnel water intrusion due to increased permea­ complexes at NTS. This experience bility of the adjacent aquitards or tran­ indicates that even in the weak rock found secting faults. at NTS no visible effects from an explo­ Theoretical calculations and compari­ sion of 100 kt would be expected in tunnels sons with past detonations lead to the con­ and mines more than about one mile from clusion that there can be no fractures the detonation and, in the majority of cases, created by the Rio Blanco explosion be­ no visible damage would be expected far­ tween about 350 and 5G00 ft below the ther than about one-half mile away. 47 surface. The full extent of the mineral- Since no fault motion and no cracking bearing region falls within this range. in the region of occurrence of these min­ Motion along preexisting faults in the eral resources is expected, the increase vicinity of nuclear detonations at NTS of water intrusion does not appear to be a have been observed and reported. How­ real possibility. ever, there is no surficial evidence that Similar considerations of these potential such motion has changed the permeability effects will need to be made in each loca­ of these faults. By examining the tion for which nuclear stimulation is pro­ explosion-induced fault motion, one would posed. However, on the basis of the Rio expect that no fault farther than about Blanco studies it would appear that no 7000 ft (measured on the surface) from a threat will be presented to the development 56 100-kt detonation could be moved. Since of mineral resources in these areas and there are no known faults within 2| mi of that future development of these gas reser­ Rio Blanco, no such motion is expected. voirs can be accomplished prior to, or However, the location of nuclear stimu­ concurrent with, mineral resource de­ lated wells will need careful evaluation velopment using cooperation and good on the basis of proximity to major faults; management techniques.

Public Acceptance

Public acceptance, both of the tech­ sition. In Rulison several injunctions nical feasibility experiments and the were sought initially to stop the detona­ subsequent commercial development of tion and subsequently to prevent the post- fields, will be a major factor in the de- shot flaring program. In all instances velopment and use of the technology. The the courts ruled that the experiment Gasbuggy experiment generated no oppo- could proceed, thereby clearly establishing

-44- the propriety of AEC procedures and sulted in generally favorable public reac­ guidelines regarding release of tions. radioactivity and carrying out peaceful nu­ Ultimately, public acceptance will re­ clear explosions. volve around a few key points: (1) a public Since Rulison, considerable effort has awareness of the shortage of fuel and other been made to work with those groups in natural resources; (2) a direct benefit Colorado who opposed Rulison, as well as (such as jobs or severance and ad valorem State advisory groups and environmental taxes) to those most directly inconvenienced organizations, in an effor. to acquaint them by the detonations; (3) an awareness that fully with planned precautionary measures the radioactivity associated with products and to acknowledge their criticisms. In from nuclear detonations is extremely addition, a series of public meetings on small; and (4) the actual demonstration— Plowshare, the Miniata test, and the through the carrying out of experimental publication of the Rulison results have re­ projects—that the AEC can accurately

Table IS. Benefits to the government from nuclear gas stimulation.

Increment in Present value of cumulative total 1980 1986 1991 through 1991* Gas Production (Tcf/yr) 0,867 1.750 2.480 Gas Value at 40f /Mcf (millions of dollars) 347 700 992 3756

Revenue to government (thousands of dollars) County ad valorem taxes 16.7 33.7 48.0 180.5 State severance taxes 3.1 6.1 8.6 32.8 Federal royalty0 43.3 87.6 124.4 468.7 Total government revenue 63.1 127.4 181.0 682.0

Balance-of-payments effect (millions of dollars) Equivalent cost of imported oild 458 925 1315 4952 Equivalent cost of imported liquefied natural gas 606 1229 1741 6562

^aken as 5.5% of net value after U. S. royally. Taken as 1% of net value after U. S. royalty. Taken as 12^% of gross production value. Taken as $3.00/bbl paid to foreign producers and shippers (energy equivalent of 1 bbl oil = 5680 Mcf of gas). Taken as 70£ /Mcf paid to foreign producers and shippers; U. S. price after vaporization would be 80$ /Mcf. f Discounted at 8%.

-45- predict the effects of nuclear explosions We have proposed that field develop­ and that its procedures do adequately pro­ ment could start in 1977, increasing as tect the public health and safety and mini­ shown in Table 5 to a continuing construc­ mize impact on the environment. tion rate of 100 wells per year. Depend­ Based on the schedules for commer­ ing on the total area available in each cial development proposed in this re­ locality for development, it may be ex­ port. Table 15 presents the financial pected that several hundred wells would be benefits to government over the next constructed over an extended period and 20 yr from the sale of nuclear stimu­ that these wells would continue to produce lated gas at 40£/Mcf. gas for 20 to 50 yr. If instead of producing this domestic Such a program would greatly affect gas the equivalent energy is provided to the population levels and economic bases U.S. consumers by importing crude oil of these remote areas, since this level at $3.00 per barrel, the balance of trade of long-term construction and operating effect would result in an outflow of $1.3 activity might be expected to result in billion per year by 1991. If the require­ local populations of about 10,000 to 20,000 ment for this energy must be met by gas, people. Thus, in addition to the tax the importing in 1991 of an equivalent revenues to local government from pro­ quantity of liquefied natural gas at duction of the gas, there would be a far 70f /Mcf paid to foreign producers and larger stimulus to the local economies shippers would result in an outflow of from the economic multiplier resulting almost $1.7 billion per year. from this new local industry.

Technical Development Programs for Achieving Commercial Usage

If nuclear gas stimulation is to DEVELOPMENT OF THE GAS- be utilized for increasing the nation's STIMULATION EXPLOSIVE supply of natural gas, a number of The explosives used in the Gasbuggy development programs must be under­ and RuJison experiments were existing taken. While we have answered a num­ designs developed to meet military weapons ber of the most important questions re­ criteria. The explosive for commercial garding technical feasibility and safety, gas stimulation must be designed (1) to explosives must be designed to mini­ leave a minimum amount of tritium, (2) to mize the radioactivity problem, costs fit into as small a drill hole as practicable, must be further reduced, the optimum (3) to withstand the high temperatures and use of multiple explosives must be pressures existing in gas fields, (4) to be determined, and operational pro­ sufficiently rugged to withstand the shock cedures must be worked out. These from previous sequentially fired explo­ efforts are described in the following sives, and (5) to be of minimal cost (i. e., sections. to be easily manufactured and use

46- minimum quantities of fissionable mate­ fission yield. The Diamond explosive is rials). designed with this factor in mind. These goals are difficult to meet Additional sources of tritium are from simultaneously and are not met fortuitously neutron reactions with shielding materials by a weapon explosive. A common de­ or with constituents of the surrounding nominator for all these factors is cost, rock. An (n, T) reaction on B and an since desirable features always can be (n,o-) reaction on Li are the two dominant achieved for more money. Therefore, sources. Since the lithium occurs naturally tradeoffs between features are essential in the rock (and 0.5 to 3% of the neutrons to attain minimal costs. entering the soil will form tritium for the An explosive that embodies most of range of gas-field soils for which we have these features has been designed; the word analyses), it is advantageous to keep the Diamond is intended to ser\'e as the generic neutrons from entering the soil. name for this .lass of explosives. Salient The post-explosion tritium from each features of these design factors and their 30-kt Diamond explosive in the Bio Blanco impact on thi diamond explosive are as Event is expected to be less than 0.1 g follows. (1000 Ci). This low level of post-explosion tritium represents a significant step in the Diameter development of a gas stimulation explosive. Diameter is important because of Krypton-8 5 is the other radioisotope limitations <..!' drilling technology and of concern. It is a fission product and its drilling cost. It is more difficult to design presence is an unavoidable consequence of an explosive with the desired character­ the use of the fission process. istics at a small diameter than at a large diameter. The cost of the explosive will Downhole Conditions generiilly increase as the diameter de­ The explosive is designed to be capable creases. The diameter of the Diamond of withstanding an external hydrostatic explosive canister is less than 8 in.; it pressure of 10,000 psi and temperature as can therefore be emplaced in a 9-5/8-in. - high as 350°F. o. d. casing. Modification of the explosive To protect against high temperatures for sequential firing may lead to a some­ there is a system (illustrated in Fig. 22) what increased diameter. that utilizes the latent heat of vaporization of an internal water supply to provide the Gaseous Radionuclide Production necessary cooling. The advantages of The reduction of post-explosion tritium such a system are its simple operation, levels is the single most important tech­ inexpensive components, and lack of need nical consideration. Because a thermonu­ for surface pcwer. The main disadvantage clear explosive can produce between 0.7 is that the system has a limited life; when and 5 g of tritium per kiloton of yield, a the water supply is exhausted the explosive fission explosive has an inherent advantage will heat up and become unusable. in that only about 0.1 mg of tritium is To protect against high pressures there produced in ternary fission per kiloton of is a high-strength steel canister over the

-47- v Water vapor''"-

L,, ^AKJuidf water in ——-^

Cooling - '-System. ,_

'a porator —f r^-t-^ Wuter vapor absorber for

Heat conductor —»» • ' • (copper) it'

Pressure 10,00Opsi Temperature 350 F

Fig. 22. Temperature controls for underground nuclear explosives.

explosive. In addition, the internal parts the explosive design affect the cost. The are designed to take as much load as cost factor was considered at every step possible. The main problem in the canister in the design of the present Diamond explo­ design arises in choosing a low-cost yet sive, and a continuing effort will be made adequate-strength steel that is resistant to make the explosive as inexpensive as to the corrosive effects found in deep holes. possible.

Sequential Firing A Diamond explosive was tested in the Currently the Diamond explosive may Miniata Event at the NTS on July 8, 1971. be detonated only in the simultaneous mode. The purpose was to verify that the explo­ The sequential mode will require a sub­ sive together with a simpli '.ied firing stantial effort to develop an explosive system would perform as designed. capable of performing reliably after having The measured yield of about 82 kt is in been subjected to the stresses generated excellent agreement with that predicted by the previous explosions. before the shot. Results indicate that the experiment was completely successful. Cost Although the purposes and constraints As previously mentioned, all aspects of of this experiment as conducted at NTS

-48- were not consistent with a meaningful fracturing by the later shots. Whether direct measurement of postshot tritium simultaneous or sequential firing is levels, all diagnostic results are in superior from a fracturing viewpoint can­ harmony with the conclusion that the not be determined without experimentation. amount of tritium produced in a gas field Such enhancement could reduce tha costs environment would be as predicted. of stimulating a given section by 20 to 50% and might increase gas production by NUCLEAR EFFECTS comparable amounts. Figures 3 and 5 show the locations of As illustrated in the section on gas proposed postshot fracture-measurement production, the cost of stimulating a given and pressure-monitoring holes to be gas section and the amount of gas that can drilled into the fractured regions resulting be recovered depends critically on an from the Rio Blanco and Wagon Wheel ex­ understanding of the fracturing effects of periments. Such measurements are single and multiple explosions. Based on necessary to achieve understanding of the our data and those of the Soviets and the effects of multiple chimneys and to achieve French, the fracture dimensions in a hard, confidence in our ability to predict such brittle rock such as granite are quite well effects from calculations based on experi­ known. On the other hand, in salt there ments of this type. are no significant permanent fractures. Nuclear-effects data relative to under­ Data from Gasbuggy indicate that the standing the role of fractures in gas pro­ fairly high clay content in the gas-bearing duction also should be obtained in sub­ Pictured Cliffs formation acted to inhibit sequent nuclear production tests by adding the formation of permanent fractures. We instrumentation to such projects. The believe that in a shale with less clay, as details of the type and frequency of such at Rulison and in the Green River Basin, add-on experiments cannot be fully specified larger permanent fracture systems will until the gas-production experiments are result. Whether such fractures will stay better defined. open at 10,000 tc 14,000 ft is not known. Studies ci the chemical interactions The use of multiple explosions should occurring in the chimney are of critical lead to the enhancement of fracturing, importance in understanding and predicting whether simultaneous or sequential firing radioactivity behavior. Figures 23 and 24 is used. For simultaneous firing, the show the radioactivity and gas composition much higher stress level in the region of from Gasbuggy and Rulison.*4 0 ' 41 It is interaction, as well as the reinforcement evident that significant chemical reactions of lateral movement In this region, should and exchange processes were going on lead to more extensive compressive and inside the chimneys after the detonations. tensile failure. For sequential firing, Since each chimney will present a some­ the presence of the chimney and the frac­ what different chemical environment, ture zone resulting from the earlier shots some variation in the chemical state of will provide free surfaces for the genera­ the tritium can be expected. These tion of reflections and subsequent tensile differences need to be understood so that

-49- a- u-Ui_LI 1 1 1 1 i 1 M program to reduce the cost of nuclear R T ta / ITTT T •, 10 L/ltil l 1 . /V ° ' J gas stimulation. ' ^V^ tritium Obviously, there is a great deal of i - interaction between these development •n8 Si J ' 85|<^\^ /- U ^""-"^ programs and the nuclear-explosives nt s 1 >^. ~ 3 « : design effort described above, particularly - ^V -

^—i 1—i— tilAfrcl to ***••:

I ii I I I I id " lb- I \ ! !o. JUL 12 2 4 6 8 10 1212 4 6 8 10 12 1967 1968 '1969 Month and year

Fig. 23. Flow rate, composition, and radioactivity of Gasbuggy gas.

every measure can be taken to mini­ mize the radioactivity produced in the gas. While the seismic damage problem for single explosions is reasonably wfell understood at the present time, the use of multiple explosives, whether sequential or simultaneous, as well as the greater depths raises a number of new questions that must be answered. 500 Therefore, additional research in the Total production of dry gas — 10°ft° areas of seismic motion and damage Fig. 24. Composition and radioactivity must be undertaken as a part of any of Rulison gas.

-50. EXPLOSIV E OPERATIONS SYSTEM for a period of time at several different rates and record the corresponding down- To achieve the low fielding costs pro­ hole pressure. By matching these data jected in Table 7, a major engineering with theoretical calculations of the flow program must be mounted to develop new process, an understanding of the extent operational procedures and techniques. of the fractures and the role they play can For example, new and better methods of be gained. However, in the general c*se reentering the chimney region through the the interpretation is not unique and addi­ emplacement hole are requited. To tional pressure data are needed in the evaluate the concept of sequential emplace­ fracture region, as well as beyond. As a ment and detonation of explosives one at a result of many years' experience with time, extremely reliable methods of conventional wells, a good deal of retaining a sealed emplacement hole understanding of their results has been above each chimney will need to be developed. However, the nuclear- developed. stimul&tion case is significiantly differ­ A closely related area of engineering ent in scale and kind, and so far only study is the operational system needed two nuclear wells are available for for carrying out emplacement and detona­ study. tion. A recently developed concept, shown To develop a good understanding of the in Fig. 25, envisages the use of cement l'racture zone (particularly for multiple stemming immediately above the explosive explosions) and the role it plays and 10 to act as a pressure seal. Fluid stemming optimize the spacing and placement of the would fill the remainder of the hole to the explosives, definitive experiments in gas- surface. Removal of the explosive firing production engineering would appear very cable for subsequent reentry is the necessary. Figures 3 and 5 illustrate such troublesome problem here; in this concept, proposed experiments in which an addi­ high-strength cable immersed in the fluid tional hole is drilled in ihe fracture zone stemming would break at the cement-fluid of a multiple gas-stimulation amplication interface when stressed and could be pulled so that pressures can be monitored during from the hole. Low-strength cable re­ production from the emplacement/reentry maining in the cement could be drilled hole. The use of two such holes would be out with the cement. To minimize still better; such data make the solutions fcosts, a minimum number of vehicles unique when matched by two-dimensional would be used for explosive delivery, gas-flow calculations and should yield a firing cable connection, and remotely very good understanding of the important controlled firing. parameters for nuclear gas stimulation. Since not all gas reservoirs are alike tn GAS-RESERVOIR PRODUCTION their flow characteristics and because TECHNOLOGY various spacings should be tried with The best method of evaluating any gas nuclear explosives, several experiments well, whether it be conventional or nuclear may be necessary for a full under­ stimulated is to produce gas from the well standing.

51- DELIVERY RE-ENTRV PRODUCTION

Fig. 25. Commercial fieldii.jj concept for a nuclear explosive for gna stimulation. Policy Issues Requirki^ Covernment and Industry Action

There is no question that additional produced per explosive will need to be sources of gas for our nation's needs must declassified so that design of commercial be developed. It is also clear that devel­ production wells can proceed. opment of no one single new source can meet the burgeoning demand; all potential INDUSTRY ACTIONS sources must be considered and as many as appear practical developed. AEC Chairman J. R. Schlesinger in a 53 Nuclear gas stimulation has been shoivn recent speech reminded industry that to be technically feasible but requires the role of the AEC is to provide service considerable technological development and support in nuclear matters but it is before it can contribute natural gas to our up to industry to provide the incentive and national supply in an economically attrac­ resources for the establishment of com­ tive way. A number of actions must be mercial nuclear enterprises. Nuclear- taken by government and by industry for stimulated gas production still awaits the the technological development program to execution of a several-year technological be accomplished and for the establishment development program that will involve of a nuclear-stimulated-gas industry. substantial expenditures. Although a small number of companies have come forward GOVERNMENT ACTIONS to propose, fund, and execute a few joint industry-government experiments, it is It must be recognized that for industry apparent that a number of companies to assess accurately the required amount holding mineral leases on properties suit­ of capital investment and return on that able for nuclear gas stimulation have not investment, firm information is needed seen fit to commit their effort. on (1) the prices to be charged by the AHC It is recognized that the funds required for the nuclear explosives, (2) the gas for such experiments may be too great for sales prices to be allowed by the Federal all but £ few companies to risk on a Power Commission, and (3> the levels of unilateral basis. However. ways to pool radioac cy in the distributed gas to be funds from more than one company for allowed ny the AEC, as based on standards such purposes are known; for exam pi .--, to be established by the Environmental the electric utilities industry is proposing Protection Agency. Present law permits to carry out research and development the use of nuclear explosives in joint through a nonprofit foundation, and the gas government-industry experiments. How­ industry is already conducting such re­ ever, after the research and development search on coal gasification through the program is completed, a law must be institute of Gas Technology.a9,6° passed to permit commercial use of If the burden of industrial sponsorship nuclear explosives. In addition, informa­ for nuclear stimulation falls too heavily tion such as canister diameter and quan­ an only the presently participating com­ tity of internal and external radioactivity panies while others wait for the technology

-53- to be developed, completion of the devel­ development and minimal research and opment program may not occur and com­ development funds necessary for govern­ mercial prodr tion may never come to ment contractors and safety, more ex­ pass. periments stretched over 6 or 7 yr would be required and the total cost would be JOINT ACTIONS—THE TECHNOLOGICAL increased. DEVELOPMENT PROGRAM The nuclear explosive will be continually A 5-yr program of technological devel­ improved as experience is gained in actual opment will be required to achieve com­ field use. The nuclear-effects data will mercial gas production. One or two nu­ be obtained primarily through governmt.it- clear experiments will be required to funded research and development "add-ons" measure the environmental conditions re­ to specific projects. Building an under­ sulting from a nearby nuclear detonation standing of the generation of the seismic and *.o test the successful operation of a waves and distribution of the radioactivity hardened explosive fired in the sequential is necessary to minimize the chance of an mode. Pilot development tests involving unforeseen occurrence in future projects the construction of groups of three to five and to learn just how far it is prudent to wells in each new location will be necessary go in cost-reduction proposals. Fractur­ to prove out the gas productivity and ing research will be an effort to find out economics of nuclear stimulated wells how few explosives can be used to stimu­ using multiple detonations. late a given reservoir section and still be We suggest that the government's role interconnected so that the emplacement would be to develop the explosives and the hole can be used for reentry. Radio­ understanding of the nuclear effects of chemical and chemical work should help these explosives. Industry's role would in understanding how the shot horizons be to join with the government by proposing can be selected to minimize CO„ and specific joint experimental projects, fund­ tritium production and in deciding on the ing a major share of the field test costs, best methods for the disposal of tritiated and applying its research and development water. While these issues are of interest capabilities to the reservoir-production to a specific project sponsor, the relevance problems. is more toward being better able to apply Should the government decide that the understanding of these effects to other nuclear gas stimulation is an alternative areas and depths; hence the recommenda­ warranting its policy and funding support, tion of government funding. The joint we believe the development program could projects are obviously necessary to test be accomplished in about 5 yr for $100 to for gas production and to learn how to $150 million, of which 60% might be funded efficiently carry out nuclear explosions in by the government and 40% by industrial gas fields. companies. Alternatively, if the develop­ At the conclusion of this program, the costs ment program were to be paced by in­ for field development should be well estab­ dustrial interest and funding, with the lished and the technical questions relating government contributing only the explosive to nuclear stimulation should be answered.

-54- BENEFITS investment could be returned many times in royalties. The return to the various The primary beneficiary will be the state and local taxing jurisdictions ranges American consumer, who would be pro­ from 6| to 12|%. The companies involved vided a new supply of relatively low cost, would, of course, recover their expenses convenient, clean fuel. The government's and derive their profit from the sale of the gas.

-55- References

1. G. Werth et al., An Analysis of Nuclear-Explosive Gas Stimulation and the Program Required for Its Development, Lawrence Livermore Laboratory, Rept. UCRL-50966 (1971). 2. Hearings before the Subcommittee on Minerals, Materials, and Fuels, Committee on Interior and Insular Affairs, United States Senate, Nov. 13-14, 1969. 3. The Cleveland Press, Sept. 30, 1970. 4. Notice of Proposed Changes in the FPC Gas Tariff National Gas Pipeline of America, Docket No. RP-70-42, June 29, 1970. 5. Federal Power Commission Order No. 431 (18CFR 2.70) Docket No. R-418, Apr. 15, 1971. 6. Letters have been sent by the following gas pipeline transmission companies to their distributor and/or industrial customers notifying them not to expect increases in gas supply: Tennessee Gas Transmission Co. (June 16, 1970), Southern Natural Gas Co. (May 16, 1970), El Paso Natural Gas Co. (Aug. 16, 1970), United Gas Pipeline Co. (FPC Docket CP70-278). 7. Future Natural Gas Requirements of the United States, vol. 4, Future Require­ ments Agency, Denver Research Institute, Denver, Colorado (1971). 8. U. S. Energy Outlook—An Initial Appraisal 197 1-1985, vol. I, National Petroleum Council, Washington, D.C. (1971). 9. R. B. Morton, Secretary, U.S. Department of the Interior, address before the American Gas Association, Oct. 18, 1971. 10. G. W. Frank, H. F. Coffer, and G. R. Luetkehans, "Economics of Nuclear Gas Stimulation," in Symposium on Engineering with Nuclear Explosives, Jan. 14-16, 1970, Las Vegas, Nev., Government Printing Office, Washington, D.C. (1970), p. 577-596. 11. D. Montan, Project Rulison Gas Flow Analysis, Lawrence Livermore Laboratory, Rept. UCRL-73263 Preprint (1971); presented at the American Nuclear Society Meeting, Oct. 1971, Miami, Fla. 12. A. E. Sherwood, Transient Flow in a Gas Reservoir Stimulated by a Nuclear Explosion: Project Gasbuggy, Lawrence Livermore Laboratory, Rept. UCRL- 71868 (1969). 13. Project Rio Blanco Feasibility Study—Piceance Basin, Colorado, Equity Oil Co., Salt Lake City, Utah (1970). 14. L. A. Rogers, Project Wagon Wheel: Nuclear Explosive Stimulation of a Natural Gas Well, presented at 71st National Meeting of American Institute of Chemical Engineers, Dallas, Tex., Feb. 22, 1972. 15. R. W. Terhune, Prediction of Underground Nuclear Explosion Effects in Wagon Wheel Wheel Sandstone, Lawrence Livermore Laboratory, Rept. UCRL-50993 (1971).

-56- 16. C. H. Atkinson, Nuclear Fracturing Prospects for Low Permeability Hydro­ carbon Reservoirs in the United States, presented at Preshot Gasbuggy Symposium, Farmington, N. Mex., Sept. 18, 1967. 17. Reserves of Crude Oil, Natural Gas Liquids, and Natural Gas in the United States and Canada and United States Productive Capacity as of December 31, 1970, American Petroleum Institute, Washington, D. C, May 1971. 18. Report of the Potential Gas Committee, Mineral Resources Institute, Colorado School of Mines, Golden, Colo., June 1971. 19. A. Holzer, Gasbuggy in Perspective, Lawrence Livermore Laboratory, Rept. UCRL-7217 5 (1970). 20. M. Reynolds Jr. et al., "Project Rulison: A Preliminary Report," in Symposium on Engineering with Nuclear Explosives, Jan. 14-16, 1970, Las Vegas, Ncv., Government Printing Office, Washington, D„C. (1970), p. 597. 21. R. P. Lemon and H. J. Patel, The Effect of Nuclear Stimulation on Formation Permeability and Gas Recovery at Project Gasbuggy, Paper SPE-3624, presented at the 46th Annual Society of Petroleum Engineers Fall Meeting, Oct. 3-6, 1971, New Orleans, La. 22. L. A. Rogers, "Determining the Explosion Effects on the Gasbuggy Reservoir from Computer Simulation of the Postshot Gas Production History," in Symposium on Engineering with Nuclear Explosives, Jan. 14-16, 1970, Las Vegas, Nev., Government Printing Office, Washington, D. C. (1970), p. 698. 23. Report on Interpretation of Test Data from Project Rulison in the Rulison Field, Garfield County, Colorado, DeGolyer &McNaughton, Dallas, Tex., Dec. 6, 1971. 24. Project Rio Blanco Nuclear Stimulated Reservoir Predictions, CER Geonuclear Corp., Las Vegas, Nev., Mar. 31, 1971; published in Hearings before the Joint Committee on Atomic Energy, Congress of the U. S., 92nd Congress, Part 4, pp. 2908ff. 2 5. A. L. Edwards, TRUMP: A Computer Program for Transient and Steady-State Temperature Distributions in Multidimensional Systems, Lawrence Livermore ! Laboratory, Rept. UCRL-14754 Rev. 2 (1969). 26. A. L. Edwards, TRUMP Computer Program: Calculation of Transient Laminar Fluid Flow in Porous Media, Lawrence Livermore Laboratory, Rept. UCRL- j 50664 (1969). t 27. Economics of Stimulating Natural Gas Reservoirs with Nuclear Explosives, i Committee on Industrial Plowshare Applications, Atomic Industrial Forum, J New York, Nov. 1970. : 28. M. W. Reynolds, Jr., Austral Oil Co., private communication to B. Rubin, Feb. 16, 1972. if 29. W. J. Frank, "Characteristics of Nuclear Explosions," in Proceedings of the _i Third Plowshare Symposium, April 1964, Lawrence Livermore Laboratory, £ Rept. TID-7695 (1964).

-57- 30. "U. S. Utilities Flood Over $1 Billion Into Gas Search," Oil and Gas Journal, Oct. 25, 1971, p. 39. 31. "South Louisiana Gas Prices Go Up August 1," Oil and Gas Journal, July 26, 1971, p. 78. 32. J. S. Shaw, Jr., President, Southern Natural Gas Co., speech before the Natural Gas Men of Houston, June 17, 1971. 33. "All Sources of Gas Said Vital to U.S.," Oil and Gas Journal, June 2, 1971, p. 92. 34. "SNG: How Much, At What Cost, How Soon in the U. S. ?", Oil and Gas Journal, Dec. 6, 1971, p. 31. 35. E. A. Walsh, Vice President, El Paso Natural Gas Co., statement before the Committee on Interior and Insular Affairs, U.S. Senate, Nov. 18, 1971. 36. "AGA and U.S. Department of Interior Sign Agreement for Associated Research in Coal-to-Gas Conversion Program," Gas Industries, Sept. 1971. 37. Report on the Current Gas Supply Situation in California, California Public Utilities Commission, Utilities Division, Gas Branch, San Francisco, Calif., June 1971. 38. D. L. Coates, "Computer Analyzer Pipeline Design," Oil, and Gas Journal, Dec. 21, 1970. 39. J. P. O'Donnell, "Pipeline Economics," Oil and Gas Journal, Aug. 2, 1971. 40. C. Smith, Project Gasbuggy Gas Quality Analysis and Evaluation Program Tabulation of Radiochemical and Chemical Analytical Results, Lawrence Livermore Laboratory, Rept. UCRL-50635 (1969). 41. C. Smith, Chimney Gas Radiochemistry in Nuclear Gas Stimulation Applications, Lawrence Livermore Laboratory, Rept. UCRL-73269 (1971). 42. C. Barton et al., "Radiological Considerations in the Use of Natural Gas from Nuclearly Stimulated Wells," Nuclear Technology, vol. 11, July 1971. 43. M. Hendrickson, The Dose from Krypton-85 Released to the Earth's Atmosphere, Battelle Northwest Laboratories, Richland, Wash., Rept. BNWL-SA-3233A (IAEA-SM-147/12) (1970). 44. T. V. Crawford, Lawrence Livermore Laboratory, private communication, April 19, 1972. 45. Estimates of Ionizing Radiation Doses in the United States, 1960-2000, Environ­ mental Protection Agency, Rockville, Md., Draft Report, June 1971. 46. Technical Discussion of Off-site Safety Program for Underground Nuclear Detonations, USAEC Nevada Operations Office, Las Vegas, Nev., Rept. NVO-40 (Rev. 2) (1969). 47. G. C. Rizer, A Method of Predicting Seismic Damage to Residential Type Structures from Underground Nuclear Explosions, Lawrence Livermore Laboratory, Rept. UCRL-50959 (1970). 48. Environmental Statement—Rio Blanco Gas Stimulation Project, U.S. Atomic Energy Commission, Washington, D. C., Rept. WASH-1519 (1971).

-58- 49. J. Gofman and A. Tamplin, "Radiation, The Invisible Casu ..., ' Environment, vol. 12, No. 3 (1970). 50. L. Pauling, "Genetic and Somatic Effects of High Energy Radiation," Bulletin of Atomic Scientists, vol. 26, No. 7 (1970). 51. E. P. Radford et al., "Statement of Concern," Environment, vol. 11, No. 7 (1969). 52. R. D. Evans, J. T. Keane, and M. M. Shar.ahan, chapter on radiogenic irradia­ tion in Radiobiology of Plutonium, B. J. Stover and W. S. Jee, Eds. (University of Utah Press, Salt Lake City, Utah, 1972). 53. Presentation Before the Governor's (Colorado) Special Advisory Committee on the Rio Blanco Nuclear Stimulation Project, The Oil Shale " . "poration, October 19, 1971. 54. R. W. Terhune, Predictions of Spall Phenomena and Near-Surface Effects for Project Rio Blanco, Lawrence Livermore Laboratory, Rept. UCID-15922 (1971;. 55. F. Holzer and D. O. Emerson, Possible Effects of the Rio Blanco Project on the Overlying Oil Shale and Mineral Deposits, Lawrence Livermore Laboratory, Rept. UCRL-51163 (1971). 56. F. A. McKeown and D. D. Dickey, "Fault Displacement and Motions Related to Nuclear Explosions," Bull. Seismol. Soc. Am., vol. 59, p. 2253 (1969). 57. Consolidated Civil Actions C-1702, C-1712, C-1722, R. L. Crowther et al. vs Dr. G. T. Seaborg et al., U.S. District Court, District of Colorado, March 14, 1970. 58. J. R. Sehlesinger, Chairman, U.S. Atomic Energy Commission, speech before the Atomic Industrial Forum/American Nuclear Society, Bal Harbour, Fla., Oct. 1971. 59. Electric Utilities Industry Research and Development Goals through the Year 2000, Report of the R&D Goals Task Force to the Electric Research Council, New York (1971). 60. Report of AGA Redex Committee on Acceleration of Commercial Gasification of Coal, American Gas Association, Arlington, Va. (1970).

59- Appendix A

ALTERNATIVE GAS SUPPLY METHODS

This discussion of the alternatives for such leases due to possible environmental A-4 obtaining increased gas supplies is an effects." amplification of the topics in Table 10. Imports of gas by pipelines from Canada have been growing steadily over Conventional Exploration in the the past few years. Prospects for addi­ U. ii. and Canada" tional gas finds in Canada appear very Conventional exploration and drilling favorable and considerable investment in in geologically favorable locations repre­ exploration undoubtedly will occur. How­ sents the best method for increasing ever, recent estimates indicate an import domestic gas supplies, and the petroleum, level of only 2.3 Tcf/yr by 1985,A~5 partly A- industry has been spending about $1 billion because of Canadian export restrictions. per year on gas exploration for the past Delivery of gas to U.S. markets from A-l few years." The gas transmission remote northwestern Canada or Arctic pipeline companies have committed ap­ island regions will be costly and will re­ proximately an additional $1 billion quire additional pipeline construction. during 1970-71 for this purpose be­ cause a ruling by the FPC allowed Import of Liquefied Natural Gas them to include in their rate base ad­ It is probable that import of LNG will vanced payments to gas producers for grow very rapidly in the coming years. exploration. 30 ' A-2 However, the Large quantities of gas will be available FPC recently stopped further advanced from North Africa and the Middle East if payments of this kind. A-3 sufficiently large investments are made Much of the onshore U. S. down to in foreign liquefaction plants, special 10,000 or 15,000 feet already has been refrigerated tankers, and U.S. storage explored; thus the favorable areas for and regasification plants. The El Paso new gas finds appear to be offshore, on­ Natural Gas Company has filed for and shore at depths below 15,000 ft, or in obtained partial approval from the FPC more remote regions such as Alaska and for import of 0.36 Tcf/yr of LNG from 35 A-7 the Canadian Arctic islands. Since these Algeria. ' The disadvantages of this locations are more difficult to explore, method are the higher gas sales price, finding and developing such gas supplies the dependence of U. S. consumers on an probably will take 2 or 3 yr longer than easily interruptible foreign source, and usual. Further delays may occur due to the adverse effect on the U. S. balance of the current lack of availability of federal trade. leases for offshore properties in favorable Development of the technology for locations and recent procedural restric­ liquefying, storing, and sea transport tions by the U. S. courts on granting of of LNG has been funded entirely by

-60- industry. Commercial deliveries operation in a number of different coun- A-10 from Algeria to markets in Europe tries" for as long as 30 yr. Although have been underway for several improvements in efficiency have been A-9 years, so that further developmental made, the process has operational draw­ funding does not appear necessary. backs in its fixed-bed handling of coal and ash that cause it to be less efficient than Synthetic Gas more recently developed fluidized bed Gas can be synthesized by several processes. At least five new processes routes from hydrocarbon fluids and from (plus variants) are in the advanced stagei coal. Commercially proved processes of development; three of these are just for conversion of naphtha anH light oil entering or have entered the pilot plant feedstock are readily available; as of stage and the other two may follow in A-ll December 1971 plans had been announced about 2 yr. However, none of the for construction of at least 13 gas synthesis advanced methods is expected to be in 34 plants by the gas transmission industry. commercial production before 1978 to Although the capital investment for such 1980; therefore, some companies with plants is not excessive ($30 million for urgent supply needs may proceed with 35 40 Bcf/yr), the cost of naphtha feedstocks the construction of Lurgi process plants. is high and the resultant gas sales price A coal gasification plant to produce about probably will be more than $1 per thousand 0.08 Tcf/yr will cost about $250 million; cubic feet at the plant. In addition, do­ the coal mine required to supply it will o mestic supplies of naphtha and light oil cost about $40 million. The amount of feedstocks are very limited because of coal needed to supply such a plant is about competitive demand by the petrochemical 6 million tons/yr. Thus, an addition to industry. Import of naphtha further affects gas supplies of 1 Tcf/yr would require the balance of trade and may come under 60 million tons/yr of coal —10% of the oil import restrictions. Therefore, most present U. S. total coal production. of these plants are planned for use on an A 5-yr joint government-industry re­ intermittent, seasonal basis to meet peak search and development program to carry demands. This source of gas does not this technology from its present research appear to be a solution to the long-term status to commercial production was supply problem. started in June 1971. The planned Because the vast coal reserves of the government annual funding level of $20 mil­ U. S. represent a source of hydrocarbon lion was reduced to $15 million for Fiscal fuels that should last for 200 or 300 yr, Year 1972. Total government funding is there can be no doubt that coal gasification expected to be about $100 million. eventually will come to supply a significant portion of our gas supplies. Nuclear Stimulation The principal method for gasification of Our proposed commercial production coal in current commercial operation is schedule for nuclear stimulation of the the Lurgi high-pressure process. Large Green River and Piceance Basins, as plants of the Lurgi type have been in shown in Fig. 14, indicates that a gas

-61- production rate of I Tcf/yr would bo is about 8% of the gross national product, reached in 1982. The required capital the industry now utilizes more than 14% of investment in nuclear-stimulated gas wells the gross capital available for private to that date would amount to $1.4 billion. investment — more than 26% of me amount It is anticipated that the needed funding to spent annually in the U. S. for investment A-12 complete the 5-yr research and develop­ in new plants and equipment. A rough ment program will range from $100 to estimate of the capital requirements for $150 million, shared between government the energy industry from 1970 to 1985 and industry. indicates that the gas industry needs are Thus, it may be seen that gas produced about 15% of the total. In view of the very from nuclear-stimulated wells has the large amounts of capital that will be re­ potential of being better than all other quired to meet currently projected energy sources except conventional exploration needs and the increasingly stiff competi­ in terms of required investment, gas sales tion between different energy sources as price, and level of research and develop­ well as from other demands for capital, ment funding, and it is competitive with concern has been expressed by officials the others in terms of time scale needed of government and the banking community to produce commercially worthwhile over the availability of sufficient funds to quantities. meet these requirements. ' There­ fore, it will become increasingly impor­ Competition for Investment Capital tant to choose for development those A striking feature of the entire U. S. energy resources that not only show a energy industry is that it is very capital- profitable return but also require the intensive. Although the gross purchase smallest capital investment. In this re­ value of energy (gas, coal, petroleum in gard, gas production from nuclear stimu­ all forms, and electricity) by consumers lated wells compares very favorably.

-52- References

A-l. Joint Association Survey of the U. S. Oil qnd Gas Producing Industry, American Petroleum Institute, Washington, D.C. (1968, 1969, and 1970). A-2. "FFC Mulls Gas-Line Accounting Changes," Oil and Gas Journal, Oct. 12, 1970. A-3. "FPC Reins in Pipelines' Cash Advances," Oil and Gas Journal, Nov. 15, 1971. A-4. "Bar to Gulf Sale Imperils Mixon Policy," Oil and Gas Journgl, Dec. 27, 1971. A-5. G. A. Mills, "Gas from Coal—Fuel of the Future," Environmental Science and Technology, vol. 5, p. 1178(1971). A-6. "Canada Rejects Increase in Gis Exports," Oil and Gas Journal, Nov. i9, 1971. A-7. "FPC Staff Halves Algerian LMG Deal," Oil and Gas Journal, Aug. 23, 1971. A-8. C. M. Sliepcevich, "Liquefied Natural Gas, A New Source of Energy," American Scientist, vol. 53, p. 260 (1965). A-9. P. C. Egan and D. W. Ward, "LNG, Its Production, Handling and Use," Cryogenics, Aug. 1969. A-10. "Manufactured Gas," in Encyclopedia of Chemical Technology, 2nd ed., vol. 10 (Interscience Publishers, New "York, 1963-65), pp. 367ff. A-11. Annual Report 1971, Office of Coal Research, U.S. Department of the Interior, Washington, D.C. (1971). A-12. Energy Policy Issues for the United States During the Seventies, prepared for the National Enerpy Forum by Arthur D. Little, Inc., Cambridge, Mass. (1971), p. 7. A-13. W. A. Lockwood, Sr., Vice President, First National City Bank of New York, "Energy Financing—A Money Famine Ahead?," address before the National Energy Porum, Washington, D.C. , Sept. 1971. A-14. J. N. Nassikas, Chairman, Federal Power Commission, "An Analysis of the Current Energy Problem," presentation at the Electrical World conference "Energy in the Seventies, " Jan. 14-15, 1971, Washington, D.C.

-63- Appendix B

RADIOACTIVITY IN THE GAS

Here we discuss additional details per­ exposure to maximum combustion product taining to radioactivity concentrations in concentrations downwind of power plants. the gas pipelines and to the assumptions The maximum dose would be less than useii in the consumption models. 1.0 to 0.70 mrem/yr. For the extreme case of individuals using unvented heating Uniform Mixing Model and appliances (which are illegal in many In this model, as field development communities), the maximum exposure progresses, gas from new wells will be would be about five times that given by mixed with that from older wells in the the upper curve in Fig. 18. The average field, and radionuclide concentrations in exposures shown in Fig. 18 do not include the pipeline v/ill gradually decrease as shown by the broken curves in Fig. B-l, assuming complete mixing of gas from the 100 two basins. It is further assumed that the gas will be uniformly diluted with all the other gas being delivered to California from out of state. (The projected out-of- state supply was assumed to be 80% of the total demand, which "was the proportion 10 37 U in 1971). The resulting radionuclide Q. pipeline concentrations are shown by the solid lines in Fig. B-l. The annual- average whole-body doses to the California population from tritium and krypton-85 that result from burning the diluted gas are shown in Fig. 18. The lower curve O represents the annual average exposure U to individuals, which includes (1) the ex­ ' After dilutioi posure from domestic use, with all heating and appliances vented except gas ranges, and (2) the population-weighted average 0.1 I I I I I I 1_J I I I L 1976 1980 1984 1988 1992 1996 2000 exposure from outside air that contains Year combustion products from all sources. As shown, the average dose would be less Fig. B-l. Radionuclide concentrations than 0.64 to 0.45 mrem/yr. The upper in gas distributed in California curve shows the annual-average maximum assuming uniform mixing with total gas delivered to the exposure to individuals; this results from state.

-64- the small fraction of individuals with un- 1000 vented heating and appliances. • Pipeline concentrations If dilution with the entire out-of-state before dilution with current supply is not possible, individual exposures Los Angeles power plant demand would increase in proportion to the lesser dilution. However, after the sixth year of •After dilution production the stimulated gas would repre­ U 100 sent more than half of the estimated out- a. of-state .supply; therefore, with no dilution after the sixth year, exposures would at V Krypfon-85 most be a factor of two higher than indi­ cated. After the nineteenth year, the stimulated gas supply slightly exceeds the 10 estimated out-of-state supply, and the J individual doses shown correspond to use YTritiu m (upper limit) of undiluted stimulated gas.

Separate Pipeline for First-Year Gas from New Wells 1 J_ 1976 1980 1984 1988 1992 1996 2000 An alternative consideration is to Year separately collect all the first-year Fig. B-2. Radionuclide concentrations production from new wells and deliver in gas distributed to power it specifically for consumption in electric- plants in California assuming the plants receive only first- power generating stations. The expected year gas from new wells. quantity of this gas at steady state (0.47 Tcf/yr after the third year) would power plant consumption and no dilution be about 1.7 times the consumption of gas- is assumed thereafter. burning power plants now in Los Angeles. The atmospheric exposure model for The second-year and later gas then could Los Angeles 42 has been scaled to estimate be freely delivered with essentially no the exposure to individuals from exclu­ concern for its radioactivity content. sive power-plant consumption of stimu­ (Since average concentrations in the sec­ lated gas. Figure 19 shows these esti­ ond year are expected to be about 1/1000 mates, which assume dilution during the of those of the first year, the correspond­ first 3 yr; the population weighted average ing dose for such gas usage would be about exposure would be less than 0.11 mrem/yr 1/1000 of the values in Fig. 18.) and the maximum exposure would be less Figure B-2 shows pipeline tritium and than 2.1 mrem/yr7 The excess gas in the krypton-85 concentrations in the special pipeline (about 70% of the current Los pipeline before and after dilution with the Angeles power-plant consumption) is current consumption by power plants in assumed to be utilized in power plants Los Angeles. After the third year the supply exceeds the current Los Angeles See footnote on p. 34.

-65- elsewhere in California under similar an increasing number of new wells brought exposure conditions. Thus, individual into production during this period. The doses would remain about the same, but population used for the upper curve (uni­ the population at risk would be about 1.7 form dilution model) was that of the entire times that estimated for Los Angeles. state, because of uniform gas usage; that for the lower curve (power-plant use of Population Dose first-year gas from new wells) assumed Figure 20 summarizes the man-rem exposure of only the Los Angeles popula­ population exposure in California for the tion during the first 3 yr and 1.7 times the two alternative delivery and use situations Los Angeles population after the fourth outlined above. For uniform mixing of the year. In the latter model, if the power gas, the population exposure would be less plants were located away from urban than 15,000 man-rem/yr. Although the centers, the annual man-rem dose would dilution assumed affects individual doses, be lower in proportion to the lower popula­ the man-rem population exposure is tion at risk. Even with the assumed u. ^.an approximately proportional to the total power-plant locations, the population radioactivity released and the population dose from this alternative use of stim­ exposed and is qualitatively independent ulated gas is a factor of seven to ten of dilution. Both man-rem curves in lower than for the uniform dilution Fig. 20 rise rapidly m early years due to model.

-66-