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• 11. [Image] Geothermal direct heat project, Marlin, Texas: Environmental assessment

  	The Federal action addressed is retrofitting a heating and hot water system in a hospital at Marlin, Texas, with a geothermal preheat system. The project will be located within the existing hospital boiler ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal direct heat project, Marlin, Texas: Environmental assessment Year: 1979 The Federal action addressed is retrofitting a heating and hot water system in a hospital at Marlin, Texas, with a geothermal preheat system. The project will be located within the existing hospital boiler room. One supply well will be drilled in an existing adjacent parking lot. Fluid disposal from operation will depend on fluid properties and may be by surface disposal to existing street drains, by surface disposal to a new drainage system, or by injection into a new injection well, depending on total dissolved solids (TDS) content. Environmental impacts of construction are expected to be small because of the existing structures and paved areas. Construction run-off and geothermal flow-test fluid will pass through a small pond in the city park, lowering its water quality, at least temporarily. Construction noise is not expected to be out of character with existing noises around the hospital. Project operation is not expected to produce significant impacts because of the decision point to determine fluid composition prior to designating a disposal method. Injection would be into a saline aquifer, and surface discharge would not appreciably lower water quality in the Brazos River; DOE/EA-0067 Title: Geothermal direct heat project, Marlin, Texas: Environmental assessment Year: 1979 The Federal action addressed is retrofitting a heating and hot water system in a hospital at Marlin, Texas, with a geothermal preheat system. The project will be located within the existing hospital boiler room. One supply well will be drilled in an existing adjacent parking lot. Fluid disposal from operation will depend on fluid properties and may be by surface disposal to existing street drains, by surface disposal to a new drainage system, or by injection into a new injection well, depending on total dissolved solids (TDS) content. Environmental impacts of construction are expected to be small because of the existing structures and paved areas. Construction run-off and geothermal flow-test fluid will pass through a small pond in the city park, lowering its water quality, at least temporarily. Construction noise is not expected to be out of character with existing noises around the hospital. Project operation is not expected to produce significant impacts because of the decision point to determine fluid composition prior to designating a disposal method. Injection would be into a saline aquifer, and surface discharge would not appreciably lower water quality in the Brazos River; DOE/EA-0067 Close

• 12. [Image] Hot Dry Rock Energy Extraction Field Test: 75 Days of Operation of a Prototype Reservoir at Fenton Hill, Segment 2 of Phase I

  	Results from the first extensive field test of a man-made hot dry rock (HDR) geothermal reservoir in low permeability crystalline rock are presented. A reservoir with a small heat transfer area was utilized ...
  	Citation × Citation Citation Abstract Copy Title: Hot Dry Rock Energy Extraction Field Test: 75 Days of Operation of a Prototype Reservoir at Fenton Hill, Segment 2 of Phase I Author: Tester, J.W. (ed.) Year: 1979 Results from the first extensive field test of a man-made hot dry rock (HDR) geothermal reservoir in low permeability crystalline rock are presented. A reservoir with a small heat transfer area was utilized to study the characteristics of a prototype HDR system over a shortened lifetime. The resulting accelerated thermal drawdown was modeled to yield an effective area of 8000 m/sup 2/. In addition to the thermal effects, this test provided an opportunity to examine equipment operation, water permeation into the formation, geochemical interaction between the circulating fluid and the rock and flow characteristics including impedance and residence time distributions. Continuous monitoring for induced seismic effects showed that no activity to a Richter threshold of -1.0 was detected during the 75-day experiment Title: Hot Dry Rock Energy Extraction Field Test: 75 Days of Operation of a Prototype Reservoir at Fenton Hill, Segment 2 of Phase I Author: Tester, J.W. (ed.) Year: 1979 Results from the first extensive field test of a man-made hot dry rock (HDR) geothermal reservoir in low permeability crystalline rock are presented. A reservoir with a small heat transfer area was utilized to study the characteristics of a prototype HDR system over a shortened lifetime. The resulting accelerated thermal drawdown was modeled to yield an effective area of 8000 m/sup 2/. In addition to the thermal effects, this test provided an opportunity to examine equipment operation, water permeation into the formation, geochemical interaction between the circulating fluid and the rock and flow characteristics including impedance and residence time distributions. Continuous monitoring for induced seismic effects showed that no activity to a Richter threshold of -1.0 was detected during the 75-day experiment Close

• 13. [Image] Petrology of the Quaternary Volcanics of the Roosevelt KGRA, and Adjoining Area, Utah. Final Report, Volume 1

  	The Roosevelt KGRA (Known Geothermal Resource Area) located near Milford, Utah, is associated with a suite of quaternary silicic volcanics distributed for 15 km along the crest and western flank of the ...
  	Citation × Citation Citation Abstract Copy Title: Petrology of the Quaternary Volcanics of the Roosevelt KGRA, and Adjoining Area, Utah. Final Report, Volume 1 Author: Nash, W.P. Year: 1976 The Roosevelt KGRA (Known Geothermal Resource Area) located near Milford, Utah, is associated with a suite of quaternary silicic volcanics distributed for 15 km along the crest and western flank of the Mineral Mountains, a large tertiary granite batholith. The volcanics are high-silica rhyolites and occur as domes, flows and tuffs. Initial eruptions resulted in two flows of low viscosity, phenocryst-poor rhyolite. Later activity consisted of pyroclastic eruptions and the emplacement of at least 9 viscous domes. In addition to abundant glass the rhyolites contain alkali feldspar, plagioclase, biotite, iron-titanium oxides and small amounts of hornblende, allanite, apatite, zircon, sphene and topaz. Magmatic temperatures were about 700C and water fugacities ranged from 350 to 3450 bars. Based on water fugacity calculations it is concluded that there may have been one or more shallow magma chambers in the Mineral Range at depths of about 1.6 km. Title: Petrology of the Quaternary Volcanics of the Roosevelt KGRA, and Adjoining Area, Utah. Final Report, Volume 1 Author: Nash, W.P. Year: 1976 The Roosevelt KGRA (Known Geothermal Resource Area) located near Milford, Utah, is associated with a suite of quaternary silicic volcanics distributed for 15 km along the crest and western flank of the Mineral Mountains, a large tertiary granite batholith. The volcanics are high-silica rhyolites and occur as domes, flows and tuffs. Initial eruptions resulted in two flows of low viscosity, phenocryst-poor rhyolite. Later activity consisted of pyroclastic eruptions and the emplacement of at least 9 viscous domes. In addition to abundant glass the rhyolites contain alkali feldspar, plagioclase, biotite, iron-titanium oxides and small amounts of hornblende, allanite, apatite, zircon, sphene and topaz. Magmatic temperatures were about 700C and water fugacities ranged from 350 to 3450 bars. Based on water fugacity calculations it is concluded that there may have been one or more shallow magma chambers in the Mineral Range at depths of about 1.6 km. Close

• 14. [Image] DHE (Downhole Heat Exchangers)

  	The use of downhole heat exchangers (DHE) for residential or commercial space and domestic water heating and other applications has several desirable features. Systems are nearly or completely passive ...
  	Citation × Citation Citation Abstract Copy Title: DHE (Downhole Heat Exchangers) Author: Culver, G. Year: 1990 The use of downhole heat exchangers (DHE) for residential or commercial space and domestic water heating and other applications has several desirable features. Systems are nearly or completely passive -- that is, no or very little geothermal water or steam is produced from the well either reducing or completely eliminating surface environmental concerns and the need for disposal systems or injection wells. Initial cost of pumps and installation are eliminated or reduced along with pumping power costs and maintenance costs associated with pumping often corrosive geothermal fluids. Many residential and small commercial systems do not require circulating pumps because the density difference in the incoming and outgoing sides of the loop are sufficient to overcome circulating friction losses in the entire system. The major disadvantage of DHEs is their dependence on natural heat flow. In areas where geological conditions provide high permeability and a natural hydraulic gradient, DHEs can provide a substantial quantity of heat. A single 500-ft (152 m) well in Klamath Falls, Oregon, supplies over one megawatt thermal and output is apparently limited by the surface area of pipe that can be installed in the well bore. In contrast, DHEs used in conjunction with heat pumps may supply less than 8 KW from a well of similar depth. Here output is limited by conductive heat flow with perhaps a small contribution from convection near the well bore. The highest capacity DHE reported to date, in Turkey, supplies 6 MW thermal from an 820-ft (250 m) well. There were two main goals for this project. The first was to gather, disseminate and exchange internationally information on DHEs. The second was to perform experiments that would provide insight into well bore/aquifer interaction and thereby provide more information on which to base DHE designs. 27 refs., 31 figs., 3 tabs. Title: DHE (Downhole Heat Exchangers) Author: Culver, G. Year: 1990 The use of downhole heat exchangers (DHE) for residential or commercial space and domestic water heating and other applications has several desirable features. Systems are nearly or completely passive -- that is, no or very little geothermal water or steam is produced from the well either reducing or completely eliminating surface environmental concerns and the need for disposal systems or injection wells. Initial cost of pumps and installation are eliminated or reduced along with pumping power costs and maintenance costs associated with pumping often corrosive geothermal fluids. Many residential and small commercial systems do not require circulating pumps because the density difference in the incoming and outgoing sides of the loop are sufficient to overcome circulating friction losses in the entire system. The major disadvantage of DHEs is their dependence on natural heat flow. In areas where geological conditions provide high permeability and a natural hydraulic gradient, DHEs can provide a substantial quantity of heat. A single 500-ft (152 m) well in Klamath Falls, Oregon, supplies over one megawatt thermal and output is apparently limited by the surface area of pipe that can be installed in the well bore. In contrast, DHEs used in conjunction with heat pumps may supply less than 8 KW from a well of similar depth. Here output is limited by conductive heat flow with perhaps a small contribution from convection near the well bore. The highest capacity DHE reported to date, in Turkey, supplies 6 MW thermal from an 820-ft (250 m) well. There were two main goals for this project. The first was to gather, disseminate and exchange internationally information on DHEs. The second was to perform experiments that would provide insight into well bore/aquifer interaction and thereby provide more information on which to base DHE designs. 27 refs., 31 figs., 3 tabs. Close

• 15. [Image] Atlantic coastal plain geothermal test holes, New Jersey: Hole completion reports

  	A description of the Atlantic Coastal Plains Geothermal Drilling Program and data for the following Geothermal test holes drilled in New Jersey are summarized: Site No. 40, Fort Monmouth; Site No. 41, ...
  	Citation × Citation Citation Abstract Copy Title: Atlantic coastal plain geothermal test holes, New Jersey: Hole completion reports Author: Cobb, L.B. Year: 1979 A description of the Atlantic Coastal Plains Geothermal Drilling Program and data for the following Geothermal test holes drilled in New Jersey are summarized: Site No. 40, Fort Monmouth; Site No. 41, Sea Girt; Site No. 39-A, Forked River; Site No. 38, Atlantic City; and Site No. 36, Cape May; NVO-1558-1 Title: Atlantic coastal plain geothermal test holes, New Jersey: Hole completion reports Author: Cobb, L.B. Year: 1979 A description of the Atlantic Coastal Plains Geothermal Drilling Program and data for the following Geothermal test holes drilled in New Jersey are summarized: Site No. 40, Fort Monmouth; Site No. 41, Sea Girt; Site No. 39-A, Forked River; Site No. 38, Atlantic City; and Site No. 36, Cape May; NVO-1558-1 Close

• 16. [Image] Potential Growth of Electric Power Production from Imperial Valley Geothermal Resources

  	The growth of geothermal electric power operations in Imperial Valley, California is projected over the next 40 years. With commercial power forecast to become available in the 1980's, the scenario considers ...
  	Citation × Citation Citation Abstract Copy Title: Potential Growth of Electric Power Production from Imperial Valley Geothermal Resources Author: Ermak, D.L. Year: 1977 The growth of geothermal electric power operations in Imperial Valley, California is projected over the next 40 years. With commercial power forecast to become available in the 1980's, the scenario considers three subsequent growth rates: 40, 100, and 250 MW per year. These growth rates, along with estimates of the total resource size, result in a maximum level of electric power production ranging from 1000 to 8000 MW to be attained in the 2010 to 2020 time period. Power plant siting constraints are developed and used to make siting patterns for the 400- through 8000-MW level of power production. Two geothermal technologies are included in the scenario: flashed steam systems that produce cooling water from the geothermal steam condensate and emit noncondensable gases to the atmosphere; and high pressure, confined flow systems that inject the geothermal fluid back into the ground. An analysis of the scenario is made with regard to well drilling and power plant construction rates, land use, cooling water requirements, and hydrogen sulfide emissions Title: Potential Growth of Electric Power Production from Imperial Valley Geothermal Resources Author: Ermak, D.L. Year: 1977 The growth of geothermal electric power operations in Imperial Valley, California is projected over the next 40 years. With commercial power forecast to become available in the 1980's, the scenario considers three subsequent growth rates: 40, 100, and 250 MW per year. These growth rates, along with estimates of the total resource size, result in a maximum level of electric power production ranging from 1000 to 8000 MW to be attained in the 2010 to 2020 time period. Power plant siting constraints are developed and used to make siting patterns for the 400- through 8000-MW level of power production. Two geothermal technologies are included in the scenario: flashed steam systems that produce cooling water from the geothermal steam condensate and emit noncondensable gases to the atmosphere; and high pressure, confined flow systems that inject the geothermal fluid back into the ground. An analysis of the scenario is made with regard to well drilling and power plant construction rates, land use, cooling water requirements, and hydrogen sulfide emissions Close

• 17. [Image] Hot-Dry-Rock Geothermal-Energy Development Program. Annual Report, Fiscal Year 1981

  	During fiscal year 1981, activities of the Hot Dry Rock Geothermal Energy Development Program were concentrated in four principal areas: (1) data collection to permit improved estimates of the hot dry ...
  	Citation × Citation Citation Abstract Copy Title: Hot-Dry-Rock Geothermal-Energy Development Program. Annual Report, Fiscal Year 1981 Author: Smith, M.C. (comp.) Year: 1981 During fiscal year 1981, activities of the Hot Dry Rock Geothermal Energy Development Program were concentrated in four principal areas: (1) data collection to permit improved estimates of the hot dry rock geothermal energy resource base of various regions of the United States and of the United States as a whole, combined with detailed investigations of several areas that appear particularly promising either for further energy extraction experiments or for future commercial development; (2) successful completion of a 9-month, continuous, closed-loop, recirculating flow test in the enlarged Phase I System at Fenton Hill, New Mexico - a pressurized-water heat-extraction loop developed in low-permeability granitic rock by hydraulic fracturing; (3) successful completion at a depth of 4084 m (13,933 ft) of well EE-3, the production well of a larger, deeper, and hotter, Phase II System at Fenton Hill. Well EE-3 was directionally drilled with control of both azimuth and inclination. Its inclined section is about 380 m (1250 ft) vertically above the injection well, EE-2, which was completed in FY80; and (4) supporting activities included new developments in downhole instrumentation and equipment, geochemical and geophysical studies, rock-mechanics and fluid-mechanics investigations, computer analyses and modeling, and overall system design. Under an International Energy Agency agreement, the New Energy Development Organization, representing the Government of Japan has joined Kernforschungsanlage-Juelich GmbH, representing the Federal Republic of Germany, and the US Department of Energy as an active participant in the Fenton Hill Hot Dry Rock Project Title: Hot-Dry-Rock Geothermal-Energy Development Program. Annual Report, Fiscal Year 1981 Author: Smith, M.C. (comp.) Year: 1981 During fiscal year 1981, activities of the Hot Dry Rock Geothermal Energy Development Program were concentrated in four principal areas: (1) data collection to permit improved estimates of the hot dry rock geothermal energy resource base of various regions of the United States and of the United States as a whole, combined with detailed investigations of several areas that appear particularly promising either for further energy extraction experiments or for future commercial development; (2) successful completion of a 9-month, continuous, closed-loop, recirculating flow test in the enlarged Phase I System at Fenton Hill, New Mexico - a pressurized-water heat-extraction loop developed in low-permeability granitic rock by hydraulic fracturing; (3) successful completion at a depth of 4084 m (13,933 ft) of well EE-3, the production well of a larger, deeper, and hotter, Phase II System at Fenton Hill. Well EE-3 was directionally drilled with control of both azimuth and inclination. Its inclined section is about 380 m (1250 ft) vertically above the injection well, EE-2, which was completed in FY80; and (4) supporting activities included new developments in downhole instrumentation and equipment, geochemical and geophysical studies, rock-mechanics and fluid-mechanics investigations, computer analyses and modeling, and overall system design. Under an International Energy Agency agreement, the New Energy Development Organization, representing the Government of Japan has joined Kernforschungsanlage-Juelich GmbH, representing the Federal Republic of Germany, and the US Department of Energy as an active participant in the Fenton Hill Hot Dry Rock Project Close

• 18. [Image] Geothermal Reservoir Categorization and Stimulation Study

  	Analyses of the fraction of geothermal wells that are dry (dry-hole fraction) indicate that geothermal reservoirs can be fitted into four basic categories: (i) Quaternary to late Tertiary sediments (almost ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Reservoir Categorization and Stimulation Study Author: Overton, H.L. Year: 1977 Analyses of the fraction of geothermal wells that are dry (dry-hole fraction) indicate that geothermal reservoirs can be fitted into four basic categories: (i) Quaternary to late Tertiary sediments (almost no dry holes); (ii) Quaternary to late Tertiary extrusives (approximately 20 percent dry holes); (iii) Mesozoic or older metamorphic rocks (approximately 25-30 percent dry holes); and (iv) Precambrian or younger rocks (data limited to Roosevelt Springs where 33 percent of the wells were dry). Failure of geothermal wells to flow economically is due mainly to low-permeability formations in unfractured regions. Generally the permeability correlates inversely with the temperature-age product and directly with the original rock porosity and pore size. However, this correlation fails whenever high-stress fields provide vertical fracturing or faulting, and it is the high-stress/low-permeability category that is most amenable to artificial stimulation by hydraulic fracturing, propellant fracturing, or chemical explosive fracturing. Category (i) geothermal fields (e.g., Cerro Prieto, Mexico; Niland, CA; East Mesa, CA) are not recommended for artificial stimulation because these younger sediments almost always produce warm or hot water. Most geothermal fields fit into category (ii) (e.g., Wairakei, New Zealand; Matsukawa, Japan; Ahuachapan, El Salvador) and in the case of Mt. Home, ID, and Chandler, AZ, possess some potential for stimulation. The Geysers is a category (iii) field, and its highly stressed brittle rocks should make this site amenable to stimulation by explosive fracturing techniques. Roosevelt Springs, UT, Well 9-1 is in category (iv) and is a flow failure. It represents a prime candidate for stimulation by hydraulic fracturing because it has a measured temperature of 227/sup 0/C, is cased and available for experimentation, and is within 900 m of an excellent geothermal producing well Title: Geothermal Reservoir Categorization and Stimulation Study Author: Overton, H.L. Year: 1977 Analyses of the fraction of geothermal wells that are dry (dry-hole fraction) indicate that geothermal reservoirs can be fitted into four basic categories: (i) Quaternary to late Tertiary sediments (almost no dry holes); (ii) Quaternary to late Tertiary extrusives (approximately 20 percent dry holes); (iii) Mesozoic or older metamorphic rocks (approximately 25-30 percent dry holes); and (iv) Precambrian or younger rocks (data limited to Roosevelt Springs where 33 percent of the wells were dry). Failure of geothermal wells to flow economically is due mainly to low-permeability formations in unfractured regions. Generally the permeability correlates inversely with the temperature-age product and directly with the original rock porosity and pore size. However, this correlation fails whenever high-stress fields provide vertical fracturing or faulting, and it is the high-stress/low-permeability category that is most amenable to artificial stimulation by hydraulic fracturing, propellant fracturing, or chemical explosive fracturing. Category (i) geothermal fields (e.g., Cerro Prieto, Mexico; Niland, CA; East Mesa, CA) are not recommended for artificial stimulation because these younger sediments almost always produce warm or hot water. Most geothermal fields fit into category (ii) (e.g., Wairakei, New Zealand; Matsukawa, Japan; Ahuachapan, El Salvador) and in the case of Mt. Home, ID, and Chandler, AZ, possess some potential for stimulation. The Geysers is a category (iii) field, and its highly stressed brittle rocks should make this site amenable to stimulation by explosive fracturing techniques. Roosevelt Springs, UT, Well 9-1 is in category (iv) and is a flow failure. It represents a prime candidate for stimulation by hydraulic fracturing because it has a measured temperature of 227/sup 0/C, is cased and available for experimentation, and is within 900 m of an excellent geothermal producing well Close

• 19. [Image] The Definition of Engineering Development and Research Problems Relating to the Use of Geothermal Fluids for Electric Power Generation and Nonelectric Heating

  	The use of geothermal fluids for electric power generation and nonelectric purposes causes problems not normally encountered when pure water is used for similar purposes. These problems must be identified ...
  	Citation × Citation Citation Abstract Copy Title: The Definition of Engineering Development and Research Problems Relating to the Use of Geothermal Fluids for Electric Power Generation and Nonelectric Heating Author: Apps, J.A. Year: 1977 The use of geothermal fluids for electric power generation and nonelectric purposes causes problems not normally encountered when pure water is used for similar purposes. These problems must be identified and means developed to overcome them before geothermal energy resources can become an important source of electric power or thermal energy in the United States. Research and development projects aimed at solving problems arising from the use of geothermal fluids from known sources in the United States are listed. Problem areas covered are: impact on engineering design caused by chemical, thermodynamic, and transport properties of geothermal fluids; scaling and sludge formation; gases, volatile brine constituents, condensate chemistry; environmental problems. The research projects identified are general in nature and are not site specific. (JGB) Title: The Definition of Engineering Development and Research Problems Relating to the Use of Geothermal Fluids for Electric Power Generation and Nonelectric Heating Author: Apps, J.A. Year: 1977 The use of geothermal fluids for electric power generation and nonelectric purposes causes problems not normally encountered when pure water is used for similar purposes. These problems must be identified and means developed to overcome them before geothermal energy resources can become an important source of electric power or thermal energy in the United States. Research and development projects aimed at solving problems arising from the use of geothermal fluids from known sources in the United States are listed. Problem areas covered are: impact on engineering design caused by chemical, thermodynamic, and transport properties of geothermal fluids; scaling and sludge formation; gases, volatile brine constituents, condensate chemistry; environmental problems. The research projects identified are general in nature and are not site specific. (JGB) Close

• 20. [Image] Delineation of an electrical resistivity anomaly, Malpais area, Beowawe KGRA, Eureka and Lander Counties, Nevada

  	A simple numerical model of previously released bipole-dipole resistivity data shows the margin of the graben to be anomalously conductive below the Malpais. The conductive area has been delineated with ...
  	Citation × Citation Citation Abstract Copy Title: Delineation of an electrical resistivity anomaly, Malpais area, Beowawe KGRA, Eureka and Lander Counties, Nevada Author: Smith, C. Year: 1980 A simple numerical model of previously released bipole-dipole resistivity data shows the margin of the graben to be anomalously conductive below the Malpais. The conductive area has been delineated with data from a dipole-dipole resistivity survey run in April 1980 for this study. Detailed numerical models of these data define a 1250 m wide body with resistivities less than 20 ohm-m that appear to connect The Geysers and the graben boundary. The minimum depth to the conductor is interpreted to be 375 m; its depth extent is undetermined. The electrical data do not resolve whether the anomaly below the Malpais may be the product of a defunct hydrothermal system or the signature of an active system. If thermal gradient data detect an enhanced heat flow anomaly in the same area, the Malpais may be a viable geothermal exploration target within the Beowawe KGRA; DOE/ID/12079-7 Title: Delineation of an electrical resistivity anomaly, Malpais area, Beowawe KGRA, Eureka and Lander Counties, Nevada Author: Smith, C. Year: 1980 A simple numerical model of previously released bipole-dipole resistivity data shows the margin of the graben to be anomalously conductive below the Malpais. The conductive area has been delineated with data from a dipole-dipole resistivity survey run in April 1980 for this study. Detailed numerical models of these data define a 1250 m wide body with resistivities less than 20 ohm-m that appear to connect The Geysers and the graben boundary. The minimum depth to the conductor is interpreted to be 375 m; its depth extent is undetermined. The electrical data do not resolve whether the anomaly below the Malpais may be the product of a defunct hydrothermal system or the signature of an active system. If thermal gradient data detect an enhanced heat flow anomaly in the same area, the Malpais may be a viable geothermal exploration target within the Beowawe KGRA; DOE/ID/12079-7 Close