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This project's objectives were to evaluate the combustion-geothermal hybrid power conversion concept at the Pleasant Bayou Geopressured Well and to obtain geopressured reservoir and fluid data in long-term (3-5 years) flow test.

Among the most pressing problems constraining the development of geothermal energy is the lack of satisfactory component and system reliability. This is due to the unavailability, on a commercial scale, of cost-effective materials that can function in a wide range of geothermal environments and to the unavailability of a comprehensive body of directly related test data or materials selection experience. In 1976, the GHTD started the Geothermal Materials Program to address materials-related problems, and since 1978 Brookhaven National Laboratory has provided technical and managerial assistance in the implementation of the effort. Major successes have been attained in the development of elastomers for high-temperature applications and in the use of polymer concrete liners for corrosion protection. Both technologies have been successfully transferred to industry. Current efforts in metallic and nonmetallic materials development and corrosion protection will be summarized. In the metals area, testing of a series of experimental stainless steels has led to compositions which show a very remarkable resistance to pitting corrosion in hot chloride electrolytes. Combinations of molybdenum and nitrogen are very beneficial. Alternate materials for line shaft pump bearings have been identified through tests in simulated hot brine. Cermets and carbides show promise of extending pump life. A …

The study of geothermal reservoir behavior is presently in a state of change brought about by the discovery that reservoir heterogeneity--fractures in particular--is responsible for large scale effects during production. On the other hand, some parts of a reservoir, or some portions of its behavior. may be unaffected by fractures and behave, instead, as if the reservoir were a homogeneous porous medium. Drilling has for many years been guided by geologists prospecting for fractures (which have been recognized as the source of production), but until recently reservoir engineers have not studied the behavior of fractured systems under production. In the last three years research efforts, funded by the Department of Energy and others, have made significant progress in the study of fractures. The investigations into simulation of fracture flow, tracer analysis of fractured systems, and well test analysis of double porosity reservoirs are all advancing. However, presently we are at something of a conceptual impasse in defining a reservoir as fractured or porous. It seems likely that future directions will not continue to attempt to distinguish two separate reservoir types, but will focus instead on defining behavior types. That is, certain aspects of reservoir behavior may be considered to be …

Keynote address

This research, conducted by the Bureau of Economic Geology and the Center for Energy Studies, includes the following areas of interest; geological studies depicting pressure gradients and thermal gradients, sand distribution and fault patterns, all of which are used in petroleum exploration; geophysical data for interpretation of seismic velocities based upon lithologic changes and subsurface discontinuities; sandstone consolidation data involving changes of permeabilities with depth and diagenetic histories of Cenozoic rocks in the Gulf Coast Basin--this work also covers fluid migration pathways and resulting rock-water interactions and has led to a better understanding of generation, maturation and accumulation of hydrocarbons; work on salinity of formation waters covering several areas of study, such as chemical analysis to anticipate scale and corrosion problems, and investigations of logging techniques to better ascertain salinity of use of well logs; reservoir continuity studies, together with computational modeling to assist in estimation of ultimate recoveries and formation drives; rock mechanics studies, which have recently led to the development of new models to account for creep and determine compressibilities of sandstones and shales in geopressured environments; co-production of gas and water in watered-out gas reservoirs.

One of the major factors presently inhibiting the exploitation of geothermal energy is the high cost of drilling and completing geothermal wells. The cost of these wells typically ranges from $1 M to $3 M, which are several times that of an oil or gas well of comparable depth. These high costs are primarily driven by the harsh environment associated with geothermal reservoirs. The high temperatures which are inherent to the resource cause rapid degradation of conventional drill bits and preclude the use of conventional drilling fluids. Geothermal formations are typically hard and highly fractured. This results in low rates of penetration, high rates of drilling fluid loss, and difficulties in obtaining competent completions. The chemical composition of the downhole geothermal fluids causes extensive scaling, and combined with high temperatures, cause corrosion of drill pipe, casing, and logging equipment. Current activities include development of high temperature drilling fluids, methods for plugging lost circulation zones, advanced rock cutting techniques, and borehole instrumentation. Three specific projects which are being pursued, each at a different stage of development include: a method for locating fractures which do not intersect the wellbore, a laboratory for simulating lost circulation zones--to be used for development of new …

The Moana geothermal area is the largest single low- to moderate-temperature geothermal resource in the State of Nevada presently employed for direct-use applications. Approximately 150 individual wells, representing a total estimated investment of $5 to $7 million, are presently used to provide heat and hot water to more than 130 private residences, several churches and two large motels. Although most of the wells are constructed to meet the heating needs of individual homes, a large-scale district space heating system, designed to supply heat to 60 houses from a single well, is now being developed. usable temperatures range from 50 to 99 C (120 to 210 F); well depths range from 60 to 400 m (100 to 1300 ft). The number of new wells coming on-line in Moana is two to three per month. Development of the resource has been largely unregulated and questions dealing with reported reservoir temperature and water level declines, loss of artesian flow, and fluid disposal have recently surfaced. In October 1982, a geologic and hydrologic research program began that was designed to provide detailed geothermal reservoir data to present to prospective developers. The program combines geophysical, geochemical, and geological surveys of the Moana resource area with …

In 1970, Los Alamos began an informal study of the possible usefulness of hot dry rock (HDR) energy systems based on circulation of water through hydraulic fractures connecting two wellbores drilled into hot crustal rock of low initial permeability and free-water content. In 1973 this was established as a formal HDR Program. It has since been sponsored by DOE and its predecessor agencies, with supplementary support since 1980 by agencies of the governments of West Germany and Japan. In the meantime, complementary HDR projects have been initiated in Germany, Japan, the United Kingdom, Sweden, France, and the Soviet Union, and several other countries have undertaken HDR resource evaluations and theoretical background studies. The HDR Program is now truly international, although the broadest and most advanced effort is still at Los Alamos.

This paper briefly discusses findings from a recent study of needs in drilling research and development that was conducted at Sandia National Laboratories for the Office of Energy Research of the Department of Energy. The purpose of the study was to identify areas in which research and development are necessary in order to meet future drilling requirements. The complete study will be documented in a soon-to-be-published final report.

The U.S. Interagency Geothermal Coordinating Council was a multi-agency group charged with identifying and reducing barriers to geothermal energy development in the U.S. Many of the issues covered related to regulations for and progress in the leasing of Federal lands in the West for power development. The IGCC reports are important sources of historical information.

The attendance at the Workshop was similar to last year's with 123 registered participants of which 22 represented 8 foreign countries. A record number of technical papers (about 60) were submitted for presentation at the Workshop. The Program Committee, therefore, decided to have several parallel sessions to accommodate most of the papers. This format proved unpopular and will not be repeated. Many of the participants felt that the Workshop lost some of its unique qualities by having parallel sessions. The Workshop has always been held near the middle of December during examination week at Stanford. This timing was reviewed in an open discussion at the Workshop. The Program Committee subsequently decided to move the Workshop to January. The Tenth Workshop will be held on January 22-24, 1985. The theme of the Workshop this year was ''field developments worldwide''. The Program Committee addressed this theme by encouraging participants to submit field development papers, and by inviting several international authorities to give presentations at the Workshop. Field developments in at least twelve countries were reported: China, El Salvador, France, Greece, Iceland, Italy, Japan, Kenya, Mexico, New Zealand, the Philippines, and the United States. There were 58 technical presentations at the Workshop, of …

This presentation describes the 15 MW(e) hybrid combined cycle power plant being constructed at Honey Lake, near Susanville, California. The power plant will use a wood fired system topping cycle, an organic Ranking (binary) bottoming cycle, and geothermal heating of combustion air and organic working fluid. In addition to a technical description, project economics, project merits, and project status are presented.

Inhibited, flashed brine is thermodynamically poised to deposit CaCO{sub 3}. Eventually the scale inhibitor will be overcome by dilution in native reservoir fluid, sorption on rocks, slow overgrowth of CaCO{sub 3}, decomposition, or some combination of processes. Consequences to the reservoir which receives the fluid apparently have not been previously explored. However, Huff-Puff tests (monitored backflow of injected tracers), carried out at East Mesa in the summer of 1983, have provided a starting point for addressing the questions. An effective lifetime of about 14 hours is indicated for one inhibitor. Additionally, reactions between injected fluid and native resource fluid have been observed in two contexts: (1) the native fluid around the disposal well is the unflashed counterpart of the injectate; (2) the native fluid around the disposal well is chemically distinct from the injectate and from its unflashed counterpart. In the two cases investigated, situation (1) yielded significant reaction (deposition of CaCO{sub 3}) whereas, situation (2) appeared unreactive. These outcomes have important implications regarding the mechanics of reservoir management for long-term electricity production.

The U.S. Department of Energy-sponsored Geothermal Reservoir Well Stimulation Program was initiated in February 1979 to pursue industry interest in geothermal well stimulation work and to develop technical expertise in areas directly related to geothermal well stimulation activities. This report provides an overview of the two experiments conducted in the high-temperature reservoir in Baca, New Mexico. The report discusses resource and reservoir properties, and provides a description of the stimulation experiment, a description of the treatment evaluation, and a summary of the experiment costs. (DJE-2005)

Subsidence and fault-related surface displacements are the chief environmental concerns related to the long-term production of large volumes of fluids from geopressured-geothermal reservoirs. Environmental monitoring efforts at the three designed test well sites in Louisiana (Parcperdue, Sweet Lake, and Gladys McCall) have focused on leveling surveys, recording of microseismic events, and tiltmeter installation to provide baseline and fluid-production-related data useful in measuring land-surface and faulting effects of testing. Analysis of pretesting land-surface elevation surveys has revealed a complex pattern of subsidence related to sediment compaction, basin subsidence, and possibly to ground-water production and soil wetting and drying. The relative importance of each of these is not clear and the impact of geopressured-geothermal fluid production has not been determined. A three-year period of microseismic monitoring has produced reports by contractors of some 1000 suspected microseismic events; many of these require further verification. 64 events were recorded at Parcperdue, 141 at Gladys McCall, and 893 at Sweet Lake. Considering only events recorded by 5 stations or more reduces the total to 316, of which only six have the classic microseismic event characteristics. Analysis of all recorded events and their relation to fluid production and/or disposal is continuing. Tiltmeter data from Sweet Lake …

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This report addresses flash points and flammability limits of flammable gases found in waste tanks, primarily hydrocarbon mixtures derived from waste solvents. The effect of vapor pressure is discussed. Particular attention is given to Purex solvent. The pertinent facts are then applied to the safety of the waste tanks of concern.

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Progress on the direct mass spectrometric sampling of pyrolysis products from wood and its constituents is described for the period from June 1982 to February 1983. A brief summary and references to detailed reports, of the qualitative demonstration of our approach to the study of the separated processes of primary and secondary pyrolysis is presented. Improvements and additions to the pyrolysis and data acquisition systems are discussed and typical results shown. Chief of these are a heated-grid pyrolysis system for controlled primary pyrolysis and a sheathed flame arrangement for secondary cracking studies. Qualitative results of the secondary cracking of cellulose, lignin, and wood are shown as are comparisons with the literature for the pyrolysis spectra of cellulose, lignin, and levoglucosan. 'Fingerprints' for a number of materials are shown, with spectra taken under carefully controlled conditions so that sensitivity calibrations for different compounds, now being determined, can be applied.

This report describes an evaluation of fatigue crack growth in Pressurized Water Reactor (PWR) piping. The results provide supporting at the Pacific Northwest Laboratory which has the objective of evaluating the effectiveness and reliability of inservice inspection of primary coolant piping.

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