and flow tests will be conducted in the same manner as with BR-5. 3. The three production wells, BR-5, BR-10A and BR-10B, will be equipped with 28-inch tubing and liquid lift equipment. 4. The compressor system installed in Phase III will be modified to provide the necessary pressure in the fractured zone and to overcome the necessary pressure drop at a flow rate of about 12 MMSCFD. In order to provide a capability for recycle of a fraction of the off-gas, it will be necessary to provide a combination system both to pressurize the added air to the system pressure at the injection well heads and to offset the pressure drop of the recycle gas up to the production well-head. The 6,000 brake horsepower capability provided in Phase III should be adequate to provide the flow requirements indicated. 5. Two additional wells, BR-11A and BR-11B, will be drilled to a depth of 3,400 feet about 20 feet outside the wall of the chimney. These holes will be drilled and cased to a minimum ID of 6 inches to a depth of about 2,300 feet. A directional survey will be made of each hole after completion. During the course of the treatment of the fractured zone, these holes will be used for periodic wireline temperature surveys through the depth of the producing section of the oil shale formation. Periodic gas samples may be taken from selected intervals of these wells. At the conclusion of the treatment of the fractured zone, these holes can be used to provide core samples through the treated section of the oil shale. 6. Provided that the treatment of the fractured zone with production from wells BR-10A and BR-10B shows satisfactory results, two additional production wells, BR-12A and BR-12B, will be located and drilled to the same specifications as BR-10A and BR-10B, except that they will be spotted about 80 feet outside the chimney wall. The exact dis tance will depend upon the results of previous fracture studies and oil shale treatment. Limited frac ture studies will be made in drilling these wells. These production wells will use tubing and liquid lift equipment transferred from other wells. 7. Two additional wells, BR-13A and BR-13B, will be drilled to the same specifications as BR-11A and BR-11B except that they will be spotted about 60 feet outside the chimney wall. These wells will also be used for periodic temperature survey profiles as well as for recovery of gas samples during treatment of the sector beyond the first set of production wells. After completion of treatment of the sector, holes BR-13A and BR-13B can be used. to recover cores in the treated zone of the formation. 8. No additional aboveground storage requirements are envisaged for either oil or water during Phase IV. 9. During the treatment of the fracture zone, periodic temperature profiles will be taken through the wells provided for this purpose. At the surface, continuous measurements of the important process parameters will be made (ambient flow rates, temperature and pressure). Periodic or continuous sampling will be made of the composition of the gaseous effluent. Gas samples will be analyzed for chemical composition and radioactivity. Periodic measurement will be made of the volumes and densities of oil and water samples recovered. The radioactive contaminants of the liquid products will be continuously monitored. The composition of the saline constituents of the water fractions will be periodically determined. 10. At the conclusion of Phase IV and in the absence of any new experimental requirements, the aboveground process equipment will be disposed of and the surface of the land will be returned substantially to the same condition in which it was at the beginning of the experiment. SUPPLEMENTAL RESEARCH Phase I and Phase II EXPLOSIVE PERFORMANCE. A limited number of diagnostic measurements of the energy yield and other performance characteristics of the nuclear explosive will be required as a part of the Bronco experiment. These measurements will be conducted at shot time, with the exception of the analysis of melt samples recovered in post-shot drilling. ROCK PROPERTIES. Samples of pre-shot core from the vicinity of the detonation point will be subjected to laboratory tests to determine their radioactivity, chemical composition, and the following physical properties: 1. Hydrostatic compressibility up to 40 kilobars. 4. Hugoniot elastic limit. 5. High-pressure Hugoniot equation of state. 6. Sonic velocity. These data will be used as input for computer calculations of the shock wave, cavity growth, fracturing, and collapse leading to chimney formation. Core samples from post-shot holes will be analyzed for radioactivity and examined in the laboratory for permanent physical changes resulting from the explosion. GAS SAMPLING. Samples of gas will be taken in several post-shot holes to determine the extent to which radioactivity has penetrated the formation. These samples will be taken with downhole bottles on a wire line or drawn to the surface from packed-off intervals through tubing. The gas will be analyzed for chemical composition and radioactive species. This information will be helpful in evaluating the fracturing caused by the explosion, leading towards eventually establishing the fracturing mechanism. DYNAMIC EARTH MOTION. Holes BR-3 and BR-E will be fitted with peak pressure gauges, stress history transducers, and shock velocity instruments. Data from these instruments will be useful in checking the accuracy of computer code predictions of shock wave history and cavity growth. GROUND SURFACE MOTION. Accelerometers and velocity gauges will be used to measure ground surface motion within a few miles of surface zero. These data will be used in establishing minimum safe distances for equipment and facilities for subsequent explosions in the same vicinity. OTHER THEORETICAL WORK. Computer predictions will be made of the ground surface motion, the seismic wave, and the possible interaction of the chimney with overlaying aquifers. Computer computations related to recovery of oil from the chimney may also be made, in connection with Phase III. Phase III and Phase IV THERMODYNAMIC AND PHYSICAL PROPERTIES OF OIL SHALE. In situ retorting research studies at the Bureau of Mines Laramie Petroleum Research Center have been designed to provide information needed as a basis for the development of efficient methods for recovering shale oil from oil shale broken by underground nuclear explosions. Measurements have been made of the following thermodynamic properties: specific heat, heat requirements for retorting, thermal decomposition rates of oil-shale carbonates, thermal conductivity, and thermal diffusivity. Research has also been directed toward investigating the physical properties of oil shale, including the compressive strength of raw, retorted, and burned shales. The work is continuing. LARAMIE 10-TON RETORT. A superior recovery technique must insure efficient heat utilization as well as the conversion of an optimum amount of the organic matter to a liquid product. The present 10-ton retort experiment is designed to investigate the retorting of ungraded oil shale under conditions similar to those expected in a nuclear chimney. Retorting studies to date have been made on mine run shale charges containing pieces as large as 20 inches in two dimensions. The third dimension has varied from several inches to 3 or 4 feet. Yields as high as 80 percent of Fischer Assay have been achieved. CARBON RESIDUE STUDIES. Another current study will yield information on the maximum amount of heat obtainable by burning the carbonaceous residue remaining on spent shale. Results of this study should show whether a major portion of the heat required for retorting oil shale underground can be obtained by burning the organic residue remaining in the shale after retorting, or whether the heat should be generated by burning some of the product gas. LARAMIE 150-TON RETORT. A new retorting experiment, larger than the present 10-ton operation is proposed. The retorting characteristics of ungraded shale containing pieces as large as 4 feet in two dimensions will be determined. It is proposed that this experiment be conducted on shale charges of 100-150 tons, using a retorting vessel 12 feet in diameter and 45 feet high. Temperature and gas composition as functions of time and position in the bed will be recorded. Provision will be made for varying the air rate from 10,000 to 15,000 standard cubic feet per ton and the ratio of recycle gas to air from 0 to 1.5. Retorting rates will be varied but will probably average about 2 feet per day (5 lb/hr/ft2 of retort cross section). It is proposed to operate the equipment at slightly elevated pressures. From data taken in the course of retorting runs, and from careful examination of the contents of the retort at the conclusion of each run, some insight into the question of combustion front stability will be gained. OIL SHALE CRUSHING STUDIES. The crushing tendencies of various grades of oil shale when subjected to retorting conditions such as might be encountered during the retorting of the rubble column of a nuclear chimney are currently being investigated. The equipment used for this work consists of an externally heated cylindrical vessel having a capacity of approximately 150 pounds of shale. Provision is made for compressing the bed by loading with a hydraulically-operated piston Pressures of up to 500 psi, equivalent to a bed depth of approximately 1,000 feet, can be applied. Data will be indicative of the ability of various grades of shale to resist crushing and attendant reduction of bed permeability during retorting. Crushing studies will be made at subretorting temperatures as well as at retorting temperatures, and on retorted and burned shales as well as on raw shale. |