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• 1. [Image] Neutron Formation Temperature Gauge and Neutron Activation Analysis Brine Flow Meter. Final Report, October 1, 1976--March 31, 1978

  	Feasibility studies of nuclear techniques applicable to the determination of geothermal formation temperature and two-phase brine flow downhole have been performed. The formation temperature gauging technique ...
  	Citation × Citation Citation Abstract Copy Title: Neutron Formation Temperature Gauge and Neutron Activation Analysis Brine Flow Meter. Final Report, October 1, 1976--March 31, 1978 Author: Vagelatos, N. Year: 1978 Feasibility studies of nuclear techniques applicable to the determination of geothermal formation temperature and two-phase brine flow downhole have been performed. The formation temperature gauging technique involves injection of fast neutrons into the formation and analysis of the moderated slow neutron energy distribution by appropriately filtered neutron detectors. The scientific feasibility of the method has been demonstrated by analytical computational and experimental evaluation of the system response. A data analysis method has been developed to determine unambiguously the temperature, neutron absorption cross section and neutron moderating power of an arbitrary medium. The initial phase of a program to demonstrate the engineering feasibility of the technique has been performed. A sonde mockup was fabricated and measurements have been performed in a test stand designed to simulate a geothermal well. The results indicate that the formation temperature determined by this method is independent of differences between the temperature in the borehole fluid and the formation, borehole fluid density, and borehole fluid salinity. Estimates of performance specifications for a formation temperature sonde have been made on the basis of information obtained in this study and a conceptual design of a logging system has been developed. The technique for the determination of fluid flow in a well is based on neutron activation analysis of elements present in the brine. An analytical evaluation of the method has been performed. The results warrant further, experimental evaluation Title: Neutron Formation Temperature Gauge and Neutron Activation Analysis Brine Flow Meter. Final Report, October 1, 1976--March 31, 1978 Author: Vagelatos, N. Year: 1978 Feasibility studies of nuclear techniques applicable to the determination of geothermal formation temperature and two-phase brine flow downhole have been performed. The formation temperature gauging technique involves injection of fast neutrons into the formation and analysis of the moderated slow neutron energy distribution by appropriately filtered neutron detectors. The scientific feasibility of the method has been demonstrated by analytical computational and experimental evaluation of the system response. A data analysis method has been developed to determine unambiguously the temperature, neutron absorption cross section and neutron moderating power of an arbitrary medium. The initial phase of a program to demonstrate the engineering feasibility of the technique has been performed. A sonde mockup was fabricated and measurements have been performed in a test stand designed to simulate a geothermal well. The results indicate that the formation temperature determined by this method is independent of differences between the temperature in the borehole fluid and the formation, borehole fluid density, and borehole fluid salinity. Estimates of performance specifications for a formation temperature sonde have been made on the basis of information obtained in this study and a conceptual design of a logging system has been developed. The technique for the determination of fluid flow in a well is based on neutron activation analysis of elements present in the brine. An analytical evaluation of the method has been performed. The results warrant further, experimental evaluation Close

• 2. [Image] Annual Report on the Project to Design and Experimentally Test an Improved Geothermal Drill Bit

  	Progress is reported in a research and development program to design, build, and test an improved geothermal drill bit. The major tasks of the Phase I effort are entitled: failure mechanisms of existing ...
  	Citation × Citation Citation Abstract Copy Title: Annual Report on the Project to Design and Experimentally Test an Improved Geothermal Drill Bit Author: Barker, L.M. Year: 1976 Progress is reported in a research and development program to design, build, and test an improved geothermal drill bit. The major tasks of the Phase I effort are entitled: failure mechanisms of existing bits; new steels and new bearing design; and new seals and lubricants. It appears that a significant gain in drill-bit life can be attained by the use of higher-temperature steels which retain more hardness at temperatures above 260/sup 0/C (500/sup 0/F). Such steels are available, and two research bits of high-temperature steels were made and will shortly be tested in a laboratory-simulated full-scale geothermal drilling environment. Two control bits of the same design, but made with conventional drill bit steels, were also obtained for identical laboratory test runs, so that the performance of the research bits can be meaningfully assessed. Base-line properties of the steels, such as hardness and fracture toughness as functions of temperature, are being measured to further assess the value of the high-temperature steels selected for the research bits. A geothermal test vessel was designed and fabricated in which the full-scale drill bits will be tested. The vessel is capable of temperature to 427/sup 0/C (800/sup 0/F) and pressures to 35 MPa (5,000 psi). Seal and lubrication designs were studied, and the state of the art in high-temperature seals and lubricants was assessed. Some candidate seals and lubricants have been obtained for testing, and others are being procured. In addition, a seal test vessel has been designed and will soon be completed which can simulate the geothermal drilling environment in full-scale testing of seal and lubricant designs and materials. (JGB) Title: Annual Report on the Project to Design and Experimentally Test an Improved Geothermal Drill Bit Author: Barker, L.M. Year: 1976 Progress is reported in a research and development program to design, build, and test an improved geothermal drill bit. The major tasks of the Phase I effort are entitled: failure mechanisms of existing bits; new steels and new bearing design; and new seals and lubricants. It appears that a significant gain in drill-bit life can be attained by the use of higher-temperature steels which retain more hardness at temperatures above 260/sup 0/C (500/sup 0/F). Such steels are available, and two research bits of high-temperature steels were made and will shortly be tested in a laboratory-simulated full-scale geothermal drilling environment. Two control bits of the same design, but made with conventional drill bit steels, were also obtained for identical laboratory test runs, so that the performance of the research bits can be meaningfully assessed. Base-line properties of the steels, such as hardness and fracture toughness as functions of temperature, are being measured to further assess the value of the high-temperature steels selected for the research bits. A geothermal test vessel was designed and fabricated in which the full-scale drill bits will be tested. The vessel is capable of temperature to 427/sup 0/C (800/sup 0/F) and pressures to 35 MPa (5,000 psi). Seal and lubrication designs were studied, and the state of the art in high-temperature seals and lubricants was assessed. Some candidate seals and lubricants have been obtained for testing, and others are being procured. In addition, a seal test vessel has been designed and will soon be completed which can simulate the geothermal drilling environment in full-scale testing of seal and lubricant designs and materials. (JGB) Close

• 3. [Image] Seal/lubricant systems for geothermal drilling equipment

  	The development and testing of seals and lubricants for journal-type roller-cone rock bits for drilling into geothermal reservoirs at temperatures over 260/sup 0/C (500/sup 0/F) are described. The conditions ...
  	Citation × Citation Citation Abstract Copy Title: Seal/lubricant systems for geothermal drilling equipment Author: Hendrickson, R.R. Year: 1980 The development and testing of seals and lubricants for journal-type roller-cone rock bits for drilling into geothermal reservoirs at temperatures over 260/sup 0/C (500/sup 0/F) are described. The conditions experienced by seals and lubricants subjected to geothermal drilling are reviewed along with the basic design requirements for roller-cone bit seals and journal bearing lubricants. Two unique test facilities are described: a seal test machine which simulates pressures, temperatures, and mechanical eccentricities, and a lubricant tester capable of evaluating load-bearing ability at temperature and pressure. Three candidate elastomeric compounds demonstrated 288/sup 0/C (550/sup 0/F) capability and several others demonstrated 260/sup 0/C (500/sup 0/F) or greater capability. Successful elastomeric seal candidates were proprietary compounds based on EPDM, Kalrez, and/or Viton polymers. Three mechanical seals for reservoir temperatures over 288/sup 0/C (550/sup 0/F) are presented. Lubricant screening tests on more than 50 products are summarized, and several newly developed lubricants which meet both the compatibility and lubrication requirements are described. Several seal/lubricant systems are recommended for laboratory or field geothermal drilling tests in roller-cone drill bits. The future availability of drill bits for geothermal use is discussed, as well as the potential spinoffs of the program findings for nongeothermal roller-cone bits; SAND-80-7101 Title: Seal/lubricant systems for geothermal drilling equipment Author: Hendrickson, R.R. Year: 1980 The development and testing of seals and lubricants for journal-type roller-cone rock bits for drilling into geothermal reservoirs at temperatures over 260/sup 0/C (500/sup 0/F) are described. The conditions experienced by seals and lubricants subjected to geothermal drilling are reviewed along with the basic design requirements for roller-cone bit seals and journal bearing lubricants. Two unique test facilities are described: a seal test machine which simulates pressures, temperatures, and mechanical eccentricities, and a lubricant tester capable of evaluating load-bearing ability at temperature and pressure. Three candidate elastomeric compounds demonstrated 288/sup 0/C (550/sup 0/F) capability and several others demonstrated 260/sup 0/C (500/sup 0/F) or greater capability. Successful elastomeric seal candidates were proprietary compounds based on EPDM, Kalrez, and/or Viton polymers. Three mechanical seals for reservoir temperatures over 288/sup 0/C (550/sup 0/F) are presented. Lubricant screening tests on more than 50 products are summarized, and several newly developed lubricants which meet both the compatibility and lubrication requirements are described. Several seal/lubricant systems are recommended for laboratory or field geothermal drilling tests in roller-cone drill bits. The future availability of drill bits for geothermal use is discussed, as well as the potential spinoffs of the program findings for nongeothermal roller-cone bits; SAND-80-7101 Close

• 4. [Image] Geothermal Resource Exploration in Boise, Idaho

  	Exploratory drilling in Boise, Idaho, in the vicinity of the Boise Front Fault has confirmed the presence of a 170/sup 0/F (77/sup 0/C) geothermal resource below about 800 ft (244 m) near the Veterans ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Resource Exploration in Boise, Idaho Author: Nelson, L.B. Year: 1980 Exploratory drilling in Boise, Idaho, in the vicinity of the Boise Front Fault has confirmed the presence of a 170/sup 0/F (77/sup 0/C) geothermal resource below about 800 ft (244 m) near the Veterans Hospital of the Military Reserve Park. The Idaho National Engineering Laboratory (INEL), sponsored by the Department of Energy, drilled three exploratory slim holes and two deep exploratory test wells. Study results based on tests of the two exploratory-test wells are reported. Faulting related to the Boise Front Fault defines a major physiographic break in the area that acts as a subsurface conduit through which geothermal water circulates. Hydrologic tests indicate that rocks disturbed by the Boise Front Fault may be as much as ten times more permeable than those removed from the major structural lineament Title: Geothermal Resource Exploration in Boise, Idaho Author: Nelson, L.B. Year: 1980 Exploratory drilling in Boise, Idaho, in the vicinity of the Boise Front Fault has confirmed the presence of a 170/sup 0/F (77/sup 0/C) geothermal resource below about 800 ft (244 m) near the Veterans Hospital of the Military Reserve Park. The Idaho National Engineering Laboratory (INEL), sponsored by the Department of Energy, drilled three exploratory slim holes and two deep exploratory test wells. Study results based on tests of the two exploratory-test wells are reported. Faulting related to the Boise Front Fault defines a major physiographic break in the area that acts as a subsurface conduit through which geothermal water circulates. Hydrologic tests indicate that rocks disturbed by the Boise Front Fault may be as much as ten times more permeable than those removed from the major structural lineament Close

• 5. [Image] Field drilling tests on improved geothermal unsealed roller-cone bits: Final report

  	The development and field testing of a 222 mm (8-3/4 inch) unsealed, insert type, medium hard formation, high-temperature bit are described. Increased performance was gained by substituting improved materials ...
  	Citation × Citation Citation Abstract Copy Title: Field drilling tests on improved geothermal unsealed roller-cone bits: Final report Author: Hendrickson, R.R. Year: 1980 The development and field testing of a 222 mm (8-3/4 inch) unsealed, insert type, medium hard formation, high-temperature bit are described. Increased performance was gained by substituting improved materials in critical bit components. These materials were selected on bases of their high temperature properties, machinability and heat treatment response. Program objectives required that both machining and heat treating could be accomplished with existing rock bit production equipment. Six of the experimental bits were subjected to air drilling at 240/sup 0/C (460/sup 0/F) in Franciscan graywacke at the Geysers (California). Performances compared directly to conventional bits indicate that in-gage drilling time was increased by 70%. All bits at the Geysers are subjected to reaming out-of-gage hole prior to drilling. Under these conditions the experimental bits showed a 30% increase in usable hole drilled, compared with the conventional bits. The materials selected improved roller wear by 200%, friction per wear by 150%, and lug wear by 150%. These tests indicate a potential well cost savings of 4 to 8%. Savings of 12% are considered possible with drilling procedures optimized for the experimental bits; SAND-80-7079 Title: Field drilling tests on improved geothermal unsealed roller-cone bits: Final report Author: Hendrickson, R.R. Year: 1980 The development and field testing of a 222 mm (8-3/4 inch) unsealed, insert type, medium hard formation, high-temperature bit are described. Increased performance was gained by substituting improved materials in critical bit components. These materials were selected on bases of their high temperature properties, machinability and heat treatment response. Program objectives required that both machining and heat treating could be accomplished with existing rock bit production equipment. Six of the experimental bits were subjected to air drilling at 240/sup 0/C (460/sup 0/F) in Franciscan graywacke at the Geysers (California). Performances compared directly to conventional bits indicate that in-gage drilling time was increased by 70%. All bits at the Geysers are subjected to reaming out-of-gage hole prior to drilling. Under these conditions the experimental bits showed a 30% increase in usable hole drilled, compared with the conventional bits. The materials selected improved roller wear by 200%, friction per wear by 150%, and lug wear by 150%. These tests indicate a potential well cost savings of 4 to 8%. Savings of 12% are considered possible with drilling procedures optimized for the experimental bits; SAND-80-7079 Close

• 6. [Image] Testing Operations Plan: Coso Geothermal Exploratory Hole No. 1 (CGEH-1)

  	Coso Geothermal Exploratory Hole No. 1 (CGEH-1) was drilled to investigate the potential of the Coso Hot Springs Known Geothermal Resource Area (KGRA) in southeastern California. Detailed background information ...
  	Citation × Citation Citation Abstract Copy Title: Testing Operations Plan: Coso Geothermal Exploratory Hole No. 1 (CGEH-1) Author: Nevada Operations Office; Naval Weapons Center, China Lake Year: 1978 Coso Geothermal Exploratory Hole No. 1 (CGEH-1) was drilled to investigate the potential of the Coso Hot Springs Known Geothermal Resource Area (KGRA) in southeastern California. Detailed background information is contained in the drilling plan, ''Coso Geothermal Exploratory Hole No. 1 (CGEH-1),'' NVO-184, dated June 1977. The purpose of this supplement to NVO-184 is to establish a plan of operations for testing the resource after completion of well drilling activities. Major elements of this plan include setting forth the management and organizational concept to be followed, describing the generalized site activities required and the well testing operations, and establishing schedules, environmental considerations, and technical documentation requirements. The objective of this testing is to determine the well productivity and geothermal reservoir parameters. The testing will consist of both static and dynamic measurements. The static measurements will include wellhead pressure monitoring plus downhole temperature and pressure surveys conducted with the well shut in. The dynamic measurements will include downhole and surface pressure, temperature, and flow rate data with the well producing at varying rates. Two types of dynamic tests are contemplated; the first utilizing the James Method and the second utilizing a separator test system, if justified by an evaluation of the resource potential Title: Testing Operations Plan: Coso Geothermal Exploratory Hole No. 1 (CGEH-1) Author: Nevada Operations Office; Naval Weapons Center, China Lake Year: 1978 Coso Geothermal Exploratory Hole No. 1 (CGEH-1) was drilled to investigate the potential of the Coso Hot Springs Known Geothermal Resource Area (KGRA) in southeastern California. Detailed background information is contained in the drilling plan, ''Coso Geothermal Exploratory Hole No. 1 (CGEH-1),'' NVO-184, dated June 1977. The purpose of this supplement to NVO-184 is to establish a plan of operations for testing the resource after completion of well drilling activities. Major elements of this plan include setting forth the management and organizational concept to be followed, describing the generalized site activities required and the well testing operations, and establishing schedules, environmental considerations, and technical documentation requirements. The objective of this testing is to determine the well productivity and geothermal reservoir parameters. The testing will consist of both static and dynamic measurements. The static measurements will include wellhead pressure monitoring plus downhole temperature and pressure surveys conducted with the well shut in. The dynamic measurements will include downhole and surface pressure, temperature, and flow rate data with the well producing at varying rates. Two types of dynamic tests are contemplated; the first utilizing the James Method and the second utilizing a separator test system, if justified by an evaluation of the resource potential Close

• 7. [Image] Laboratory and field testing of improved geothermal rock bits

  	The development and testing of 222 mm (8-3/4 inch) unsealed, insert type, medium hard formation, high-temperature bits are described. The new bits were fabricated by substituting improved materials in ...
  	Citation × Citation Citation Abstract Copy Title: Laboratory and field testing of improved geothermal rock bits Author: Hendrickson, R.R. Year: 1980 The development and testing of 222 mm (8-3/4 inch) unsealed, insert type, medium hard formation, high-temperature bits are described. The new bits were fabricated by substituting improved materials in critical bit components. These materials were selected on bases of their high temperature properties, machinability, and heat treatment response. Program objectives required that both machining and heat treating could be accomplished with existing rock bit production equipment. Two types of experimental bits were subjected to laboratory air drilling tests at 250/sup 0/C (482/sup 0/F) in cast iron. These tests indicated field testing could be conducted without danger to the hole, and that bearing wear would be substantially reduced. Six additional experimental bits, and eight conventional bits were then subjected to air drilling a 240/sup 0/C (464/sup 0/F) in Francisan Graywacke at The Geysers, CA. The materials selected improved roller wear by 200%, friction-pin wear by 150%, and lug wear by 150%. Geysers drilling performances compared directly to conventional bits indicate that in-gage drilling life was increased by 70%. All bits at The Geysers are subjected to reaming out-of-gage hole prior to drilling. Under these conditions the experimental bits showed a 30% increase in usable hole over the conventional bits. These tests demonstrated a potential well cost reduction of 4 to 8%. Savings of 12% are considered possible with drilling procedures optimized for the experimental bits; SAND-80-7102 Title: Laboratory and field testing of improved geothermal rock bits Author: Hendrickson, R.R. Year: 1980 The development and testing of 222 mm (8-3/4 inch) unsealed, insert type, medium hard formation, high-temperature bits are described. The new bits were fabricated by substituting improved materials in critical bit components. These materials were selected on bases of their high temperature properties, machinability, and heat treatment response. Program objectives required that both machining and heat treating could be accomplished with existing rock bit production equipment. Two types of experimental bits were subjected to laboratory air drilling tests at 250/sup 0/C (482/sup 0/F) in cast iron. These tests indicated field testing could be conducted without danger to the hole, and that bearing wear would be substantially reduced. Six additional experimental bits, and eight conventional bits were then subjected to air drilling a 240/sup 0/C (464/sup 0/F) in Francisan Graywacke at The Geysers, CA. The materials selected improved roller wear by 200%, friction-pin wear by 150%, and lug wear by 150%. Geysers drilling performances compared directly to conventional bits indicate that in-gage drilling life was increased by 70%. All bits at The Geysers are subjected to reaming out-of-gage hole prior to drilling. Under these conditions the experimental bits showed a 30% increase in usable hole over the conventional bits. These tests demonstrated a potential well cost reduction of 4 to 8%. Savings of 12% are considered possible with drilling procedures optimized for the experimental bits; SAND-80-7102 Close

• 8. [Image] Investigation and evaluation of geopressured-geothermal wells. Fairfax Foster Sutter No. 2 well, St. Mary Parish, Louisiana. Volume I. Completion and testing. Final report

  	The Fairfax Foster Sutter No. 2 well, located in the East Franklin area of St. Mary Parish, Louisiana, is the first successful test of a geopressured-geothermal aquifer under the Well-of-Opportunity program. ...
  	Citation × Citation Citation Abstract Copy Title: Investigation and evaluation of geopressured-geothermal wells. Fairfax Foster Sutter No. 2 well, St. Mary Parish, Louisiana. Volume I. Completion and testing. Final report Author: Willits, M.H. Year: 1979 The Fairfax Foster Sutter No. 2 well, located in the East Franklin area of St. Mary Parish, Louisiana, is the first successful test of a geopressured-geothermal aquifer under the Well-of-Opportunity program. The section tested was the MA-6 sand of lower Miocene age which has produced large quantities of gas from the adjacent but structurally separated Garden City field. In the subject well the observed temperature was 270{sup 0}F (132{sup 0}C) and the measured gradient was 0.77 psi/ft. The gross sand thickness was 270 feet, the net sand thickness 190 feet, and the tested interval 58 net feet. The temperatures and pressures encountered approached the limits of the surface-recording bottomhole pressure gauge and particularly the single-conductor cables on which the gauges were run. The objectives of the tests were all accomplished, and data were obtained which will contribute to the overall assessment of the geopressured-geothermal resource of the Upper Gulf of Mexico basin. In general, the gas solubility (22.8 scf/bbl) was as expected for the temperature, pressure, and salinity of the brine. The produced water was more saline than expected (160,000 mg/l). The high concentrations of dissolved solids, coupled with the evolution of CO{sub 2} from these waters during production, created a scaling problem in the tubular goods and surface equipment that will have to be addressed in future tests; DOE/ET/28460-1 Title: Investigation and evaluation of geopressured-geothermal wells. Fairfax Foster Sutter No. 2 well, St. Mary Parish, Louisiana. Volume I. Completion and testing. Final report Author: Willits, M.H. Year: 1979 The Fairfax Foster Sutter No. 2 well, located in the East Franklin area of St. Mary Parish, Louisiana, is the first successful test of a geopressured-geothermal aquifer under the Well-of-Opportunity program. The section tested was the MA-6 sand of lower Miocene age which has produced large quantities of gas from the adjacent but structurally separated Garden City field. In the subject well the observed temperature was 270{sup 0}F (132{sup 0}C) and the measured gradient was 0.77 psi/ft. The gross sand thickness was 270 feet, the net sand thickness 190 feet, and the tested interval 58 net feet. The temperatures and pressures encountered approached the limits of the surface-recording bottomhole pressure gauge and particularly the single-conductor cables on which the gauges were run. The objectives of the tests were all accomplished, and data were obtained which will contribute to the overall assessment of the geopressured-geothermal resource of the Upper Gulf of Mexico basin. In general, the gas solubility (22.8 scf/bbl) was as expected for the temperature, pressure, and salinity of the brine. The produced water was more saline than expected (160,000 mg/l). The high concentrations of dissolved solids, coupled with the evolution of CO{sub 2} from these waters during production, created a scaling problem in the tubular goods and surface equipment that will have to be addressed in future tests; DOE/ET/28460-1 Close

• 9. [Image] Development of drilling foams for geothermal applications

  	The use of foam drilling fluids in geothermal applications is addressed. A description of foams - what they are, how they are used, their properties, equipment required to use them, the advantages and ...
  	Citation × Citation Citation Abstract Copy Title: Development of drilling foams for geothermal applications Author: McDonald, W.J. Year: 1980 The use of foam drilling fluids in geothermal applications is addressed. A description of foams - what they are, how they are used, their properties, equipment required to use them, the advantages and disadvantages of foams, etc. - is presented. Geothermal applications are discussed. Results of industry interviews presented indicate significant potential for foams, but also indicate significant technical problems to be solved to achieve this potential. Testing procedures and results of tests on representative foams provide a basis for work to develop high-temperature foams; SAND-79-7122 Title: Development of drilling foams for geothermal applications Author: McDonald, W.J. Year: 1980 The use of foam drilling fluids in geothermal applications is addressed. A description of foams - what they are, how they are used, their properties, equipment required to use them, the advantages and disadvantages of foams, etc. - is presented. Geothermal applications are discussed. Results of industry interviews presented indicate significant potential for foams, but also indicate significant technical problems to be solved to achieve this potential. Testing procedures and results of tests on representative foams provide a basis for work to develop high-temperature foams; SAND-79-7122 Close

• 10. [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