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• 41. [Image] Innovation Versus Monopoly: Geothermal Energy in the West. Final Report

  	The following subjects are covered: geothermal energy and its use, electric utilities and the climate for geothermal development, the raw fuels industry and geothermal energy, and government and energy. ...
  	Citation × Citation Citation Abstract Copy Title: Innovation Versus Monopoly: Geothermal Energy in the West. Final Report Author: Bierman, S.L. Year: 1977 The following subjects are covered: geothermal energy and its use, electric utilities and the climate for geothermal development, the raw fuels industry and geothermal energy, and government and energy. The role of large petroleum companies and large public utilities is emphasized. (MHR) Title: Innovation Versus Monopoly: Geothermal Energy in the West. Final Report Author: Bierman, S.L. Year: 1977 The following subjects are covered: geothermal energy and its use, electric utilities and the climate for geothermal development, the raw fuels industry and geothermal energy, and government and energy. The role of large petroleum companies and large public utilities is emphasized. (MHR) Close

• 42. [Image] The Marysville, Montana Geothermal Project (Revised)

  	The object of the Marysville Geothermal Project is to investigate a region of abnormally high geothermal heat flow near Marysville, MT, about 20 miles northwest of Helena. The research should determine ...
  	Citation × Citation Citation Abstract Copy Title: The Marysville, Montana Geothermal Project (Revised) Author: McSpadden, W.R. Year: 1974 The object of the Marysville Geothermal Project is to investigate a region of abnormally high geothermal heat flow near Marysville, MT, about 20 miles northwest of Helena. The research should determine the nature and size of the resource, how the energy might be extracted, the potential monetary value of the energy, and how similar resources elsewhere might be located. The heat source was expected to be a granitic pluton or magmatic intrusion, 10,000 to 40,000 years old, with temperatures in the range of 300 to 500°C. Originally it was thought that the pluton was at relatively shallow depths, but at present its depth and exact location are unknown Title: The Marysville, Montana Geothermal Project (Revised) Author: McSpadden, W.R. Year: 1974 The object of the Marysville Geothermal Project is to investigate a region of abnormally high geothermal heat flow near Marysville, MT, about 20 miles northwest of Helena. The research should determine the nature and size of the resource, how the energy might be extracted, the potential monetary value of the energy, and how similar resources elsewhere might be located. The heat source was expected to be a granitic pluton or magmatic intrusion, 10,000 to 40,000 years old, with temperatures in the range of 300 to 500°C. Originally it was thought that the pluton was at relatively shallow depths, but at present its depth and exact location are unknown Close

• 43. [Image] Geothermal Resources of the Eastern United States

  	Known and potential geothermal resources of the eastern United States are reported. The resources considered are exclusively hydrothermal, and the study was confined to the 35 states east of the Rocky ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Resources of the Eastern United States Author: Renner, J.L. Year: 1979 Known and potential geothermal resources of the eastern United States are reported. The resources considered are exclusively hydrothermal, and the study was confined to the 35 states east of the Rocky Mountains, excluding the Dakotas. Resource definition in these areas is based entirely on data found in the literature and in the files of a number of state geological offices. The general geology of the eastern United States is outlined. Six relatively homogeneous eastern geologic regions are discussed (MHR) Title: Geothermal Resources of the Eastern United States Author: Renner, J.L. Year: 1979 Known and potential geothermal resources of the eastern United States are reported. The resources considered are exclusively hydrothermal, and the study was confined to the 35 states east of the Rocky Mountains, excluding the Dakotas. Resource definition in these areas is based entirely on data found in the literature and in the files of a number of state geological offices. The general geology of the eastern United States is outlined. Six relatively homogeneous eastern geologic regions are discussed (MHR) Close

• 44. [Image] Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, May 1, 1976--October 31, 1976

  	Progress is reported in the development of procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological geochemical, and ...
  	Citation × Citation Citation Abstract Copy Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, May 1, 1976--October 31, 1976 Author: Costain, J.K. Year: 1976 Progress is reported in the development of procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological geochemical, and geophysical data. An optimum site for geothermal development in the tectonically stable eastern United States will probably be associated with crustal igneous rocks containing relatively high concentrations of radiogenic heat-producing elements buried beneath an insulating blanket of sediments of low thermal conductivity. Evaluation of plutonic rocks exposed in the Piedmont will aid in the interpretation of gravity and magnetic data for the Atlantic Coastal Plain. Initial results of determination of heat generation from surface samples in South Caroline are encouraging, especially if granitic igneous rocks of similar heat generation can be found beneath sedimentary insulation. Continues logging of existing wells in Coastal Plain sediments supports earlier conclusion that these sediments do behave as efficient sedimentary insulators. Higher temperatures appear to be reached at shallower depths for wells drilled in Coastal Plain sediments in the vicinity of the Georgetown, South Carolina gravity law. Detailed structural mapping in the vicinity of the warm springs in northwestern Virginia has confirmed structural control of the warm springs, and has revealed the existence of kink bands. The kink bands could be related to the development of zones of vertical permeability which serve as conduits in sedimentary rocks for ascending hot water. Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, May 1, 1976--October 31, 1976 Author: Costain, J.K. Year: 1976 Progress is reported in the development of procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological geochemical, and geophysical data. An optimum site for geothermal development in the tectonically stable eastern United States will probably be associated with crustal igneous rocks containing relatively high concentrations of radiogenic heat-producing elements buried beneath an insulating blanket of sediments of low thermal conductivity. Evaluation of plutonic rocks exposed in the Piedmont will aid in the interpretation of gravity and magnetic data for the Atlantic Coastal Plain. Initial results of determination of heat generation from surface samples in South Caroline are encouraging, especially if granitic igneous rocks of similar heat generation can be found beneath sedimentary insulation. Continues logging of existing wells in Coastal Plain sediments supports earlier conclusion that these sediments do behave as efficient sedimentary insulators. Higher temperatures appear to be reached at shallower depths for wells drilled in Coastal Plain sediments in the vicinity of the Georgetown, South Carolina gravity law. Detailed structural mapping in the vicinity of the warm springs in northwestern Virginia has confirmed structural control of the warm springs, and has revealed the existence of kink bands. The kink bands could be related to the development of zones of vertical permeability which serve as conduits in sedimentary rocks for ascending hot water. Close

• 45. [Image] Subsurface investigations at the Roosevelt KGRA, Utah. Final report

  	An investigation of the geothermal reservoir in the Roosevelt Hot Springs Known Geothermal Resource Area in Utah was carried out. The objective of this effort was to develop predictions for well production ...
  	Citation × Citation Citation Abstract Copy Title: Subsurface investigations at the Roosevelt KGRA, Utah. Final report Author: Butz, J. Year: 1979 An investigation of the geothermal reservoir in the Roosevelt Hot Springs Known Geothermal Resource Area in Utah was carried out. The objective of this effort was to develop predictions for well production capacities, based on data taken during field tests and through use of a computer model. In turn, the production information could then be used in design optimization and economic analyses for development of the resource under study. Flow tests of a geothermal well, Utah State 14-2, were conducted. Data consisting of pressure and temperature logs as a function of depth were obtained. Maximum recorded temperature was 503/sup 0/F (262/sup 0/C) and maximum pressure, 954 psia (6.58MPa) as measured under flow conditions. Tests were run at rates up to 580,000 lb/hr (73.3 kg/sec) total flow. The information gathered during the testing was reduced and compared to results of a predictive computer model. Reservoir conditions in the Roosevelt Hot Springs KGRA are such that two-phase flow exists in the wellbore and, in some cases, also in the reservoir itself. The computer model employed in the analysis reflects current efforts to improve the state-of-the-art in the prediction of two-phase pressure drops in vertical systems. Predictions at flowrates of up to 300,000 lb/hr (38 kg/sec) matched quite well with test data, while modeling at higher flowrates (to maximum tested) showed progressively greater deviation from test data. Cause of the observed degradation is postulated to be the movement of the flash horizon into the reservoir, due to drawdown at high flowrates; DOE/ET/28389-1 Title: Subsurface investigations at the Roosevelt KGRA, Utah. Final report Author: Butz, J. Year: 1979 An investigation of the geothermal reservoir in the Roosevelt Hot Springs Known Geothermal Resource Area in Utah was carried out. The objective of this effort was to develop predictions for well production capacities, based on data taken during field tests and through use of a computer model. In turn, the production information could then be used in design optimization and economic analyses for development of the resource under study. Flow tests of a geothermal well, Utah State 14-2, were conducted. Data consisting of pressure and temperature logs as a function of depth were obtained. Maximum recorded temperature was 503/sup 0/F (262/sup 0/C) and maximum pressure, 954 psia (6.58MPa) as measured under flow conditions. Tests were run at rates up to 580,000 lb/hr (73.3 kg/sec) total flow. The information gathered during the testing was reduced and compared to results of a predictive computer model. Reservoir conditions in the Roosevelt Hot Springs KGRA are such that two-phase flow exists in the wellbore and, in some cases, also in the reservoir itself. The computer model employed in the analysis reflects current efforts to improve the state-of-the-art in the prediction of two-phase pressure drops in vertical systems. Predictions at flowrates of up to 300,000 lb/hr (38 kg/sec) matched quite well with test data, while modeling at higher flowrates (to maximum tested) showed progressively greater deviation from test data. Cause of the observed degradation is postulated to be the movement of the flash horizon into the reservoir, due to drawdown at high flowrates; DOE/ET/28389-1 Close

• 46. [Image] Downhole Electrical Detection of Hydraulic Fractures in GT-2 and EE-1

  	Electrical geophysical methods including mise a la masse and self-potential (SP) for determination of hydraulic fracture characteristics were used at the hot dry rock geothermal project. Electrical and ...
  	Citation × Citation Citation Abstract Copy Title: Downhole Electrical Detection of Hydraulic Fractures in GT-2 and EE-1 Author: Kintzinger, P.R. Year: 1977 Electrical geophysical methods including mise a la masse and self-potential (SP) for determination of hydraulic fracture characteristics were used at the hot dry rock geothermal project. Electrical and induction logs indicated that the resistivity contrast between the granite and 200/sup 0/C water at the 2926-m (9600-ft) depth is a factor of 1000 or more. Thus the water in a hydraulic fracture, formed to connect two adjacent deep holes, is a good conductor compared to the confining granite. Mise a la masse-type measurements were made to help determine the characteristics for hydraulic fractures formed in each of the two geothermal holes GT-2 and EE-1. Once a hydraulic fracture has been formed, mise a la masse effects are obtained both with the fracture pressurized above hydrostatic and when depressurized to hydrostatic. This indicates that once the fracture has been created, enough natural propping exists that a conductive zone persists even when the fracture is deflated. A fracture was formed in a 18-m (60-ft) zone immediately below 1957 m (6420 ft) in EE-1. Later a set of SP logs was run in this zone with no pressure, with pressure building, with pressure decreasing, and again with the fracture depressurized. Results show that during times of change of parameters in hydraulically fractured regions in the hole, natural SP logging helps to determine the position of the fracture. However, after a fracture has come to equilibrium with fluid parameters such as temperature, pressure, salinity, and pH, an effect of the fracture may not be evident. Self-potential logs provide an excellent method for locating the bottom of steel casing that has been set in the hole Title: Downhole Electrical Detection of Hydraulic Fractures in GT-2 and EE-1 Author: Kintzinger, P.R. Year: 1977 Electrical geophysical methods including mise a la masse and self-potential (SP) for determination of hydraulic fracture characteristics were used at the hot dry rock geothermal project. Electrical and induction logs indicated that the resistivity contrast between the granite and 200/sup 0/C water at the 2926-m (9600-ft) depth is a factor of 1000 or more. Thus the water in a hydraulic fracture, formed to connect two adjacent deep holes, is a good conductor compared to the confining granite. Mise a la masse-type measurements were made to help determine the characteristics for hydraulic fractures formed in each of the two geothermal holes GT-2 and EE-1. Once a hydraulic fracture has been formed, mise a la masse effects are obtained both with the fracture pressurized above hydrostatic and when depressurized to hydrostatic. This indicates that once the fracture has been created, enough natural propping exists that a conductive zone persists even when the fracture is deflated. A fracture was formed in a 18-m (60-ft) zone immediately below 1957 m (6420 ft) in EE-1. Later a set of SP logs was run in this zone with no pressure, with pressure building, with pressure decreasing, and again with the fracture depressurized. Results show that during times of change of parameters in hydraulically fractured regions in the hole, natural SP logging helps to determine the position of the fracture. However, after a fracture has come to equilibrium with fluid parameters such as temperature, pressure, salinity, and pH, an effect of the fracture may not be evident. Self-potential logs provide an excellent method for locating the bottom of steel casing that has been set in the hole Close

• 47. [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

• 48. [Image] Preliminary Petrographic and Geophysical Interpretations of the Exploratory Geothermal Drill Hole and Core, Redstone, New Hampshire

  	A 3000 foot diamond drill hole was drilled in the Conway Granite in Redstone, New Hampshire. A comprehensive detailed petrographic and physical study of this core was made. The purpose of this study is ...
  	Citation × Citation Citation Abstract Copy Title: Preliminary Petrographic and Geophysical Interpretations of the Exploratory Geothermal Drill Hole and Core, Redstone, New Hampshire Author: Hoag, R.B. Jr. Year: 1977 A 3000 foot diamond drill hole was drilled in the Conway Granite in Redstone, New Hampshire. A comprehensive detailed petrographic and physical study of this core was made. The purpose of this study is to supply a sound data base for future geothermal and uranium-thorium studies of the drill core. An estimate of the heat flow potential of the Redstone drill hole gives a heat flow of 1.9 HFU. If only the red phase of the Conway Granite had been intersected the heat flow may have been as much as 2.7 HFU, reaching a temperature of 260/sup 0/C at 6 km. The drill hole intersected four lithologies; the green and red phase of the Conway Granite, the Albany quartz syenite and a medium-grained, hastingsite-biotite granite. The red phase has the highest and most irregular radioactivity. The irregularity is mainly due to minor variations in lithology. The Drill core intersected several alteration zones up to a thickness of 150 feet. These alteration zones represent passage of low to medium temperature fluids which might have been mineralized. The Conway Granite has the physical and chemical characteristics necessary for the formation of vein type uranium deposits. The presence of unexplained radiometric anomalies lends support to the existence of such deposits Title: Preliminary Petrographic and Geophysical Interpretations of the Exploratory Geothermal Drill Hole and Core, Redstone, New Hampshire Author: Hoag, R.B. Jr. Year: 1977 A 3000 foot diamond drill hole was drilled in the Conway Granite in Redstone, New Hampshire. A comprehensive detailed petrographic and physical study of this core was made. The purpose of this study is to supply a sound data base for future geothermal and uranium-thorium studies of the drill core. An estimate of the heat flow potential of the Redstone drill hole gives a heat flow of 1.9 HFU. If only the red phase of the Conway Granite had been intersected the heat flow may have been as much as 2.7 HFU, reaching a temperature of 260/sup 0/C at 6 km. The drill hole intersected four lithologies; the green and red phase of the Conway Granite, the Albany quartz syenite and a medium-grained, hastingsite-biotite granite. The red phase has the highest and most irregular radioactivity. The irregularity is mainly due to minor variations in lithology. The Drill core intersected several alteration zones up to a thickness of 150 feet. These alteration zones represent passage of low to medium temperature fluids which might have been mineralized. The Conway Granite has the physical and chemical characteristics necessary for the formation of vein type uranium deposits. The presence of unexplained radiometric anomalies lends support to the existence of such deposits Close

• 49. [Image] Dipole-Dipole Resistivity Survey of a Portion of the Coso Hot Springs KGRA, Inyo County, California

  	A detailed electrical resistivity survey of 54 line-km was completed at the Coso Hot Springs KGRA in September 1977. This survey has defined a bedrock resistivity low at least 4 sq mi (10 sq km) in extent ...
  	Citation × Citation Citation Abstract Copy Title: Dipole-Dipole Resistivity Survey of a Portion of the Coso Hot Springs KGRA, Inyo County, California Author: Fox, R.C. Year: 1978 A detailed electrical resistivity survey of 54 line-km was completed at the Coso Hot Springs KGRA in September 1977. This survey has defined a bedrock resistivity low at least 4 sq mi (10 sq km) in extent associated with the geothermal system at Coso. The boundaries of this low are generally well defined to the north and west but not as well to the south where an approximate southern limit has been determined. The bedrock resistivity low merges with an observed resistivity low over gravel fill east of Coso Hot Springs. A complex horizontal and vertical resistivity structure of the surveyed area has been defined which precludes the use of layered-earth or two-dimensional interpretive models for much of the surveyed area. In general the survey data indicate that a 10 to 20 ohm-meter zone extends from near surface to a depth greater than 750 meters within the geothermal system. This zone is bordered to the north and west by bedrock resistivities greater than 200 ohm-meters and to the south by bedrock resistivities greater than 50 ohm-meters. A combination of observed increases in: (1) fracture density (higher permeability), (2) alteration (high clay content), and (3) temperatures (higher dissolved solid content of ground water) within the bedrock low explain its presence Title: Dipole-Dipole Resistivity Survey of a Portion of the Coso Hot Springs KGRA, Inyo County, California Author: Fox, R.C. Year: 1978 A detailed electrical resistivity survey of 54 line-km was completed at the Coso Hot Springs KGRA in September 1977. This survey has defined a bedrock resistivity low at least 4 sq mi (10 sq km) in extent associated with the geothermal system at Coso. The boundaries of this low are generally well defined to the north and west but not as well to the south where an approximate southern limit has been determined. The bedrock resistivity low merges with an observed resistivity low over gravel fill east of Coso Hot Springs. A complex horizontal and vertical resistivity structure of the surveyed area has been defined which precludes the use of layered-earth or two-dimensional interpretive models for much of the surveyed area. In general the survey data indicate that a 10 to 20 ohm-meter zone extends from near surface to a depth greater than 750 meters within the geothermal system. This zone is bordered to the north and west by bedrock resistivities greater than 200 ohm-meters and to the south by bedrock resistivities greater than 50 ohm-meters. A combination of observed increases in: (1) fracture density (higher permeability), (2) alteration (high clay content), and (3) temperatures (higher dissolved solid content of ground water) within the bedrock low explain its presence Close

• 50. [Image] Geothermal Resource and Reservoir Investigations of U. S. Bureau of Reclamation Leaseholds at East Mesa, Imperial Valley, California

  	The study included five parts: geology, seismicity, well testing, reservoir simulation, and geochemistry. Included in appendices are: production test data and discussion, interference tests, production ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Resource and Reservoir Investigations of U. S. Bureau of Reclamation Leaseholds at East Mesa, Imperial Valley, California Author: Howard, J. Year: 1978 The study included five parts: geology, seismicity, well testing, reservoir simulation, and geochemistry. Included in appendices are: production test data and discussion, interference tests, production tests in the northern portion of the East Mesa KGRA, conversion tables, chemical analysis of fluids from East Mesa wells, and results of laboratory studies of scale samples taken from the vertical tube evaporator. (MHR) Title: Geothermal Resource and Reservoir Investigations of U. S. Bureau of Reclamation Leaseholds at East Mesa, Imperial Valley, California Author: Howard, J. Year: 1978 The study included five parts: geology, seismicity, well testing, reservoir simulation, and geochemistry. Included in appendices are: production test data and discussion, interference tests, production tests in the northern portion of the East Mesa KGRA, conversion tables, chemical analysis of fluids from East Mesa wells, and results of laboratory studies of scale samples taken from the vertical tube evaporator. (MHR) Close