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• 1. [Image] Geothermal Environmental Impact Assessment: Subsurface Environmental Assessment for Four Geothermal Systems

  	Geothermal systems are described for Imperial Valley and The Geysers, California; Klamath Falls, Oregon; and the Rio Grande Rift Zone, New Mexico; including information on location, area, depth, temperature, ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Environmental Impact Assessment: Subsurface Environmental Assessment for Four Geothermal Systems Author: Geonomics, Inc. Year: 1978 Geothermal systems are described for Imperial Valley and The Geysers, California; Klamath Falls, Oregon; and the Rio Grande Rift Zone, New Mexico; including information on location, area, depth, temperature, fluid phase and composition, resource base and status of development. The subsurface environmental assessment evaluates potential groundwater degradation, seismicity and subsidence. A general discussion on geothermal systems, pollution potential, chemical characteristics of geothermal fluids and environmental effects of geothermal water pollutants is presented as background material. For the Imperial Valley, all publicly available water quality and location data for geothermal and nongeothermal wells in and near the East Mesa, Salton Sea, Heber, Brawley, Dunes and Glamis KGRAs have been compiled and plotted. The geothermal fluids which will be reinjected range in salinity from a few thousand to more than a quarter million ppm. Although Imperial Valley is a major agricultural center, groundwater use in and near most of these KGRAs is minimal. Extensive seismicity and subsidence monitoring networks have been established in this area of high natural seismicity and subsidence. The vapor-dominated geysers geothermal field is the largest electricity producer in the world. Groundwater in this mountainous region flows with poor hydraulic continuity in fractured rock. Ground and surface water quality is generally good, but high boron concentrations in hot springs and geothermal effluents is of significant concern; however, spent condensate is reinjected. High microearthquake activity is noted around the geothermal reservoir and potential subsidence effects are considered minimal. In Klamath Falls, geothermal fluids up to 113 C (235 F) are used for space heating, mostly through downhole heat exchangers with only minor, relatively benign, geothermal fluid being produced at the surface. Seismicity is low and is not expected to increase. Subsidence is not recognized. Of all geothermal occurrences in the Rio Grande Rift, the Valles Caldera is currently of primary interest. injection of geothermal effluent from hydrothermal production Wells should remove any hydrologic hazard due to some potentially noxious constituents. Waters circulating in the LASL Hot Dry Rock experiment are potable. Seismic effects are expected to be minimal. Subsidence effects could develop Title: Geothermal Environmental Impact Assessment: Subsurface Environmental Assessment for Four Geothermal Systems Author: Geonomics, Inc. Year: 1978 Geothermal systems are described for Imperial Valley and The Geysers, California; Klamath Falls, Oregon; and the Rio Grande Rift Zone, New Mexico; including information on location, area, depth, temperature, fluid phase and composition, resource base and status of development. The subsurface environmental assessment evaluates potential groundwater degradation, seismicity and subsidence. A general discussion on geothermal systems, pollution potential, chemical characteristics of geothermal fluids and environmental effects of geothermal water pollutants is presented as background material. For the Imperial Valley, all publicly available water quality and location data for geothermal and nongeothermal wells in and near the East Mesa, Salton Sea, Heber, Brawley, Dunes and Glamis KGRAs have been compiled and plotted. The geothermal fluids which will be reinjected range in salinity from a few thousand to more than a quarter million ppm. Although Imperial Valley is a major agricultural center, groundwater use in and near most of these KGRAs is minimal. Extensive seismicity and subsidence monitoring networks have been established in this area of high natural seismicity and subsidence. The vapor-dominated geysers geothermal field is the largest electricity producer in the world. Groundwater in this mountainous region flows with poor hydraulic continuity in fractured rock. Ground and surface water quality is generally good, but high boron concentrations in hot springs and geothermal effluents is of significant concern; however, spent condensate is reinjected. High microearthquake activity is noted around the geothermal reservoir and potential subsidence effects are considered minimal. In Klamath Falls, geothermal fluids up to 113 C (235 F) are used for space heating, mostly through downhole heat exchangers with only minor, relatively benign, geothermal fluid being produced at the surface. Seismicity is low and is not expected to increase. Subsidence is not recognized. Of all geothermal occurrences in the Rio Grande Rift, the Valles Caldera is currently of primary interest. injection of geothermal effluent from hydrothermal production Wells should remove any hydrologic hazard due to some potentially noxious constituents. Waters circulating in the LASL Hot Dry Rock experiment are potable. Seismic effects are expected to be minimal. Subsidence effects could develop Close

• 2. [Image] Comparative assessment of five potential sites for hydrothermal-magma systems: summary

  	A comparative assessment of five potential hydrothermal-magma sites for this facet of the Thermal Regimes part of the CSDP has been prepared for the DOE Office of Basic Energy Sciences. The five sites ...
  	Citation × Citation Citation Abstract Copy Title: Comparative assessment of five potential sites for hydrothermal-magma systems: summary Author: Luth, W.C Year: 1980 A comparative assessment of five potential hydrothermal-magma sites for this facet of the Thermal Regimes part of the CSDP has been prepared for the DOE Office of Basic Energy Sciences. The five sites are: The Geysers-Clear Lake, CA, Long Valley, CA, Rio Grande Rift, NM, Roosevelt Hot Springs, UT, and Salton Trough, CA. This site assessment study has drawn together background information (geology, geochemistry, geophysics, and energy transport) on the five sites as a preliminary stage to site selection. Criteria for site selection are that potential sites have identifiable, or likely, hydrothermal systems and associated magma sources, and the important scientific questions can be identified and answered by deep scientific holes. Recommendations were made.; DOE/TIC-11303 Title: Comparative assessment of five potential sites for hydrothermal-magma systems: summary Author: Luth, W.C Year: 1980 A comparative assessment of five potential hydrothermal-magma sites for this facet of the Thermal Regimes part of the CSDP has been prepared for the DOE Office of Basic Energy Sciences. The five sites are: The Geysers-Clear Lake, CA, Long Valley, CA, Rio Grande Rift, NM, Roosevelt Hot Springs, UT, and Salton Trough, CA. This site assessment study has drawn together background information (geology, geochemistry, geophysics, and energy transport) on the five sites as a preliminary stage to site selection. Criteria for site selection are that potential sites have identifiable, or likely, hydrothermal systems and associated magma sources, and the important scientific questions can be identified and answered by deep scientific holes. Recommendations were made.; DOE/TIC-11303 Close

• 3. [Image] Comparative assessment of five potential sites for hydrothermal-magma systems: energy transport

  	A comparative assessment of five sites is being prepared as part of a Continental Scientific Drilling Program (CSDP) review of thermal regimes for the purpose of scoping areas for future research and drilling ...
  	Citation × Citation Citation Abstract Copy Title: Comparative assessment of five potential sites for hydrothermal-magma systems: energy transport Author: Hardee, H.C. Year: 1980 A comparative assessment of five sites is being prepared as part of a Continental Scientific Drilling Program (CSDP) review of thermal regimes for the purpose of scoping areas for future research and drilling activities. This background report: discusses the various energy transport processes likely to be encountered in a hydrothermal-magma system, reviews related literature, discusses research and field data needs, and reviews the sites from an energy transport viewpoint. At least three major zones exist in the magma-hydrothermal transport system: the magma zone, the hydrothermal zone, and the transition zone between the two. Major energy transport questions relate to the nature and existence of these zones and their evolution with time. Additional energy transport questions are concerned with the possible existence of critical state and super-critical state permeable convection in deep geothermal systems. A review of thermal transport models emphasizes the fact that present transport models and computational techniques far outweigh the scarcity and quality of deep field data. Title: Comparative assessment of five potential sites for hydrothermal-magma systems: energy transport Author: Hardee, H.C. Year: 1980 A comparative assessment of five sites is being prepared as part of a Continental Scientific Drilling Program (CSDP) review of thermal regimes for the purpose of scoping areas for future research and drilling activities. This background report: discusses the various energy transport processes likely to be encountered in a hydrothermal-magma system, reviews related literature, discusses research and field data needs, and reviews the sites from an energy transport viewpoint. At least three major zones exist in the magma-hydrothermal transport system: the magma zone, the hydrothermal zone, and the transition zone between the two. Major energy transport questions relate to the nature and existence of these zones and their evolution with time. Additional energy transport questions are concerned with the possible existence of critical state and super-critical state permeable convection in deep geothermal systems. A review of thermal transport models emphasizes the fact that present transport models and computational techniques far outweigh the scarcity and quality of deep field data. Close

• 4. [Image] A Geological and Geophysical Study of the Geothermal Energy Potential of Pilgrim Springs, Alaska

  	The Pilgrim Springs geothermal area, located about 75 km north of Nome, was the subject of an intensive, reconnaissance-level geophysical and geological study during a 90-day period in the summer of 1979. ...
  	Citation × Citation Citation Abstract Copy Title: A Geological and Geophysical Study of the Geothermal Energy Potential of Pilgrim Springs, Alaska Author: Turner, Donald L. [ed.] Year: 1980 The Pilgrim Springs geothermal area, located about 75 km north of Nome, was the subject of an intensive, reconnaissance-level geophysical and geological study during a 90-day period in the summer of 1979. The thermal springs are located in a northeast-oriented, oval area of thawed ground approximately 1.5 km{sup 2} in size, bordered on the north by the Pilgrim River. A second, much smaller, thermal anomaly was discovered about 3 km northeast of the main thawed area. Continuous permafrost in the surrounding region is on the order of 100 m thick. Present surface thermal spring discharge is {approx} 4.2 x 10{sup -3} m{sup 3} s{sup -1} (67 gallons/minute) of alkali-chloride-type water at a temperature of 81 C. The reason for its high salinity is not yet understood because of conflicting evidence for seawater vs. other possible water sources. Preliminary Na-K-Ca geothermometry suggests deep reservoir temperatures approaching 150 C, but interpretation of these results is difficult because of their dependence on an unknown water mixing history. Based on these estimates, and present surface and drill hole water temperatures, Pilgrim Springs would be classified as an intermediate-temperature, liquid-dominated geothermal system; UAG-R-271 Title: A Geological and Geophysical Study of the Geothermal Energy Potential of Pilgrim Springs, Alaska Author: Turner, Donald L. [ed.] Year: 1980 The Pilgrim Springs geothermal area, located about 75 km north of Nome, was the subject of an intensive, reconnaissance-level geophysical and geological study during a 90-day period in the summer of 1979. The thermal springs are located in a northeast-oriented, oval area of thawed ground approximately 1.5 km{sup 2} in size, bordered on the north by the Pilgrim River. A second, much smaller, thermal anomaly was discovered about 3 km northeast of the main thawed area. Continuous permafrost in the surrounding region is on the order of 100 m thick. Present surface thermal spring discharge is {approx} 4.2 x 10{sup -3} m{sup 3} s{sup -1} (67 gallons/minute) of alkali-chloride-type water at a temperature of 81 C. The reason for its high salinity is not yet understood because of conflicting evidence for seawater vs. other possible water sources. Preliminary Na-K-Ca geothermometry suggests deep reservoir temperatures approaching 150 C, but interpretation of these results is difficult because of their dependence on an unknown water mixing history. Based on these estimates, and present surface and drill hole water temperatures, Pilgrim Springs would be classified as an intermediate-temperature, liquid-dominated geothermal system; UAG-R-271 Close

• 5. [Image] Geologic Interpretation of the Geothermal Potential of the North Bonneville Area

  	Possible geothermal development for the township of North Bonneville, Washington is being investigated because of the proximity of the town to hot springs in a geologic province of good geothermal potential. ...
  	Citation × Citation Citation Abstract Copy Title: Geologic Interpretation of the Geothermal Potential of the North Bonneville Area Author: Nielson, D.L. Year: 1980 Possible geothermal development for the township of North Bonneville, Washington is being investigated because of the proximity of the town to hot springs in a geologic province of good geothermal potential. Surface expression of geothermal resources is provided by conduits through an impermeable reservoir cap and is therefore generally structurally controlled. Near North Bonneville the geologic formations that underlie potential drilling sites are the Eagle Creek formation and the Ohanpecosh Formation. The Lower Miocene Eagle Creek Formation is composed of poorly consolidated volcanic conglomerates, sandstOnes, tuffs, and includes a few minor interbedded lava flows. The Eocene-Oligiocene Ohanapecosh (Weigle) Formation in its nearest exposures to North Bonneville is composed of Volcaniclastics and lava flows. The Ohanapecosh has been altered to zeolites and clays and is therefore Well consolidated and impermeable. The lack of permeability provides the necessary reservoir cap for any geothermal system that may be present at depth. This formation, to the northeast, in the Wind River drainage is greater than 19,000 ft. thick. Circulation of geothermal heated water from this thick sequence of impermeable strata must be associated with penetrating fracture zones Title: Geologic Interpretation of the Geothermal Potential of the North Bonneville Area Author: Nielson, D.L. Year: 1980 Possible geothermal development for the township of North Bonneville, Washington is being investigated because of the proximity of the town to hot springs in a geologic province of good geothermal potential. Surface expression of geothermal resources is provided by conduits through an impermeable reservoir cap and is therefore generally structurally controlled. Near North Bonneville the geologic formations that underlie potential drilling sites are the Eagle Creek formation and the Ohanpecosh Formation. The Lower Miocene Eagle Creek Formation is composed of poorly consolidated volcanic conglomerates, sandstOnes, tuffs, and includes a few minor interbedded lava flows. The Eocene-Oligiocene Ohanapecosh (Weigle) Formation in its nearest exposures to North Bonneville is composed of Volcaniclastics and lava flows. The Ohanapecosh has been altered to zeolites and clays and is therefore Well consolidated and impermeable. The lack of permeability provides the necessary reservoir cap for any geothermal system that may be present at depth. This formation, to the northeast, in the Wind River drainage is greater than 19,000 ft. thick. Circulation of geothermal heated water from this thick sequence of impermeable strata must be associated with penetrating fracture zones Close

• 6. [Image] The Cody Hydrothermal System

  	The hot springs of Colter's Hell are the surface manifestations of a much larger hydrothermal system. That system has been studied to define its extent, maximum temperature, and mechanism of operation. ...
  	Citation × Citation Citation Abstract Copy Title: The Cody Hydrothermal System Author: Heasler, H.P. Year: 1982 The hot springs of Colter's Hell are the surface manifestations of a much larger hydrothermal system. That system has been studied to define its extent, maximum temperature, and mechanism of operation. The study area covers 2700 km/sup 2/ (1040 mi/sup 2/) in northwest Wyoming. Research and field work included locating and sampling the hot springs, geologic mapping, thermal logging of available wells, measuring thermal conductivities, analyzing over 200 oil and gas well bottom-hole temperatures, and compiling and analyzing hydrologic data. These data were used to generate a model for the hydrothermal system Title: The Cody Hydrothermal System Author: Heasler, H.P. Year: 1982 The hot springs of Colter's Hell are the surface manifestations of a much larger hydrothermal system. That system has been studied to define its extent, maximum temperature, and mechanism of operation. The study area covers 2700 km/sup 2/ (1040 mi/sup 2/) in northwest Wyoming. Research and field work included locating and sampling the hot springs, geologic mapping, thermal logging of available wells, measuring thermal conductivities, analyzing over 200 oil and gas well bottom-hole temperatures, and compiling and analyzing hydrologic data. These data were used to generate a model for the hydrothermal system Close

• 7. [Image] Geothermal energy enhancement by thermal fracture. [REX (Rock Energy Extraction)]

  	A large, vertical, circular fracture created deep within hot rock is connected to the surface through two holes. The inlet provides a source of cold water and the outlet extracts heated water. Cooling ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal energy enhancement by thermal fracture. [REX (Rock Energy Extraction)] Author: Demuth, R.B. Year: 1980 A large, vertical, circular fracture created deep within hot rock is connected to the surface through two holes. The inlet provides a source of cold water and the outlet extracts heated water. Cooling of the rock produces thermal stresses that fracture the rock adjacent to the primary crack, thereby enhancing the heat extraction rate by means of convective transport. The properties of the thermal fracture network vary with position and time. The REX code for high-speed computer was written and used to study the coupled processes of primary-crack flow and lateral thermal fracture heat transport. Calculations for elapsed times of 100 y show that thermal fracture enhancement can double the heat extraction rate over the results from conduction alone. Long-term enhancement predictions depend on data from rock-mechanics studies, which the REX code is prepared to accept as they become available.; LA-8428 Title: Geothermal energy enhancement by thermal fracture. [REX (Rock Energy Extraction)] Author: Demuth, R.B. Year: 1980 A large, vertical, circular fracture created deep within hot rock is connected to the surface through two holes. The inlet provides a source of cold water and the outlet extracts heated water. Cooling of the rock produces thermal stresses that fracture the rock adjacent to the primary crack, thereby enhancing the heat extraction rate by means of convective transport. The properties of the thermal fracture network vary with position and time. The REX code for high-speed computer was written and used to study the coupled processes of primary-crack flow and lateral thermal fracture heat transport. Calculations for elapsed times of 100 y show that thermal fracture enhancement can double the heat extraction rate over the results from conduction alone. Long-term enhancement predictions depend on data from rock-mechanics studies, which the REX code is prepared to accept as they become available.; LA-8428 Close