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• 1. [Image] Steady-State and Transient Wellbore Temperatures during Drilling

  	An extensive literature search was made to locate technical publications and computer programs relating to wellbore temperatures during drilling operations. The search confirmed the need for knowledge ...
  	Citation × Citation Citation Abstract Copy Title: Steady-State and Transient Wellbore Temperatures during Drilling Author: McDonald, W.J. Year: 1976 An extensive literature search was made to locate technical publications and computer programs relating to wellbore temperatures during drilling operations. The search confirmed the need for knowledge of transient and steady state circulating temperatures in the design of geothermal bits. Two approaches were used in calculating borehole temperatures. The steady state solution of Holmes and Swift was programmed and 2100 cases calculated for various borehole configurations. For transient temperature studies, calculations were made for ten borehole configurations. These calculations help emphasize the need for better high temperature bit performance and improved engineering procedures in drilling. The conclusions and recommendations are based on latest available technology for calculating wellbore temperatures Title: Steady-State and Transient Wellbore Temperatures during Drilling Author: McDonald, W.J. Year: 1976 An extensive literature search was made to locate technical publications and computer programs relating to wellbore temperatures during drilling operations. The search confirmed the need for knowledge of transient and steady state circulating temperatures in the design of geothermal bits. Two approaches were used in calculating borehole temperatures. The steady state solution of Holmes and Swift was programmed and 2100 cases calculated for various borehole configurations. For transient temperature studies, calculations were made for ten borehole configurations. These calculations help emphasize the need for better high temperature bit performance and improved engineering procedures in drilling. The conclusions and recommendations are based on latest available technology for calculating wellbore temperatures Close

• 2. [Image] Formation Temperature Gauge Feasibility Study. Volume II, Interim Report

  	The present status of the formation temperature gauge feasibility study is reported. It also demonstrates the feasibility of the technique in the simplified situations examined to date both analytically ...
  	Citation × Citation Citation Abstract Copy Title: Formation Temperature Gauge Feasibility Study. Volume II, Interim Report Author: IRT Corporation Year: 1977 The present status of the formation temperature gauge feasibility study is reported. It also demonstrates the feasibility of the technique in the simplified situations examined to date both analytically and experimentally. The first section deals with the theory underlying the technique. The next three sections describe the temperature gauge, the simplified model calculations of the gauge response, and the preliminary experimental measurements performed to verify the results of the computational study. The final section describes the formation temperature test stand designed to demonstrate the feasibility of the technique in the geothermal well geometry. This test stand has been assembled and measurements of the gauge response will begin shortly. These are outlined at the end of this report Title: Formation Temperature Gauge Feasibility Study. Volume II, Interim Report Author: IRT Corporation Year: 1977 The present status of the formation temperature gauge feasibility study is reported. It also demonstrates the feasibility of the technique in the simplified situations examined to date both analytically and experimentally. The first section deals with the theory underlying the technique. The next three sections describe the temperature gauge, the simplified model calculations of the gauge response, and the preliminary experimental measurements performed to verify the results of the computational study. The final section describes the formation temperature test stand designed to demonstrate the feasibility of the technique in the geothermal well geometry. This test stand has been assembled and measurements of the gauge response will begin shortly. These are outlined at the end of this report Close

• 3. [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

• 4. [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

• 5. [Image] Klamath Christian Center Heating System

  	On December 6, 1983, Dave South well contacted the Geo-Heat Center requesting information and possible assistance in analyzing problems with the geothermal wells and heating system. About a week later, ...
  	Citation × Citation Citation Abstract Copy Title: Klamath Christian Center Heating System Author: Culver, G. Year: 1984 On December 6, 1983, Dave South well contacted the Geo-Heat Center requesting information and possible assistance in analyzing problems with the geothermal wells and heating system. About a week later, Geo-Heat Center personnel met with Dave and discussed the meager amount of information then available. It was decided that the Geo-Heat Center would attempt to obtain more well data and, if possible, temperature profile the wells to determine what the problem was since available data indicated the wells should produce more heat than they were. At that time the down hole heat exchanger would provide only 116°F to 118°F water during colder periods and 125°F maximum during more moderate weather. The well was being pumped from 76 feet by a jet pump and producing about 25 gpm which was being discharged into the storm drain. Title: Klamath Christian Center Heating System Author: Culver, G. Year: 1984 On December 6, 1983, Dave South well contacted the Geo-Heat Center requesting information and possible assistance in analyzing problems with the geothermal wells and heating system. About a week later, Geo-Heat Center personnel met with Dave and discussed the meager amount of information then available. It was decided that the Geo-Heat Center would attempt to obtain more well data and, if possible, temperature profile the wells to determine what the problem was since available data indicated the wells should produce more heat than they were. At that time the down hole heat exchanger would provide only 116°F to 118°F water during colder periods and 125°F maximum during more moderate weather. The well was being pumped from 76 feet by a jet pump and producing about 25 gpm which was being discharged into the storm drain. Close

• 6. [Image] Evaluation and Design of Downhole Heat Exchangers for Direct Application; Annual Report, May 1, 1976 - July 1, 1977

  	Progress in an experimental and analytical research program to evaluate and improve the design of downhole heat exchangers (DHEs) for direct applications of geothermal energy is reported. Significant progress ...
  	Citation × Citation Citation Abstract Copy Title: Evaluation and Design of Downhole Heat Exchangers for Direct Application; Annual Report, May 1, 1976 - July 1, 1977 Author: Culver, G.G. Year: 1977 Progress in an experimental and analytical research program to evaluate and improve the design of downhole heat exchangers (DHEs) for direct applications of geothermal energy is reported. Significant progress has been achieved in characterizing flows in wells and without perforated casings and DHEs installed, determination of energy extraction rates for conventional DHEs in both cased and uncased wells, and utilization of information obtained to develop and substantiate models of heat transfer within the well. Flow characterization was obtained by experimentally measuring temperature and velocity profiles. In uncased wells, there was a relatively large vertical temperature gradient (approximately 0.5{sup 0}C/m) and insignificant measured vertical flow, while for the same wells when cased the temperature gradient was essentially zero (approximately 0.03{sup 0}C/m) and a large vertically upward flow was measured (9 to 14 cm/s as measured with a hot-film anemometer). These show that a significant connection cell is established after installation of the casing. The energy extraction rates for a conventional DHE both before and after casing of a 60 m deep well was experimentally measured. In the uncased well up to 300 kW was obtained while the cased well produced over 500 kW. Analytical heat transfer models were developed for the cased well both with and without DHEs. For the cased well without a DHE, the model predicts flow rates that agree with the measured value within about 30 percent. Further, the energy extraction rates predicted by the models agree even better with the measured values. These models allow the energy extraction rates of design parameter variations to be evaluated. At this stage, only trends can be shown but with additional substantiation they should produce optimum energy extraction designs Title: Evaluation and Design of Downhole Heat Exchangers for Direct Application; Annual Report, May 1, 1976 - July 1, 1977 Author: Culver, G.G. Year: 1977 Progress in an experimental and analytical research program to evaluate and improve the design of downhole heat exchangers (DHEs) for direct applications of geothermal energy is reported. Significant progress has been achieved in characterizing flows in wells and without perforated casings and DHEs installed, determination of energy extraction rates for conventional DHEs in both cased and uncased wells, and utilization of information obtained to develop and substantiate models of heat transfer within the well. Flow characterization was obtained by experimentally measuring temperature and velocity profiles. In uncased wells, there was a relatively large vertical temperature gradient (approximately 0.5{sup 0}C/m) and insignificant measured vertical flow, while for the same wells when cased the temperature gradient was essentially zero (approximately 0.03{sup 0}C/m) and a large vertically upward flow was measured (9 to 14 cm/s as measured with a hot-film anemometer). These show that a significant connection cell is established after installation of the casing. The energy extraction rates for a conventional DHE both before and after casing of a 60 m deep well was experimentally measured. In the uncased well up to 300 kW was obtained while the cased well produced over 500 kW. Analytical heat transfer models were developed for the cased well both with and without DHEs. For the cased well without a DHE, the model predicts flow rates that agree with the measured value within about 30 percent. Further, the energy extraction rates predicted by the models agree even better with the measured values. These models allow the energy extraction rates of design parameter variations to be evaluated. At this stage, only trends can be shown but with additional substantiation they should produce optimum energy extraction designs Close

• 7. [Image] Advanced Design and Economic Considerations for Commercial Geothermal Power Plants at Heber and Niland, California. Final Report

  	Two separate studies, involving advanced design and economic considerations for commercial geothermal power plants using liquid-dominated hydrothermal resources, are presented. In the first study, the ...
  	Citation × Citation Citation Abstract Copy Title: Advanced Design and Economic Considerations for Commercial Geothermal Power Plants at Heber and Niland, California. Final Report Author: Bechtel Corporation Year: 1977 Two separate studies, involving advanced design and economic considerations for commercial geothermal power plants using liquid-dominated hydrothermal resources, are presented. In the first study, the effects on design, capital cost, and bus bar electric energy production cost caused by an anticipated decline in available geothermal fluid temperature over the lifetime of power plants are described. A two-stage, flashed-steam energy conversion process was used for the conceptual design of the power plants, which operate from the moderate-temperature, low-salinity reservoir at Heber, California. Plants with net capacities of 50, 100, and 200 MWe (net) were investigated. The results show that it is important to include provision for geothermal fluid temperature decline in the design of power plants to prevent loss of electric energy production capability and to reduce bus bar electric energy costs. In the second study, the technical, economic, and environmental effects of adding regeneration to a 50 MWe (net) power plant employing the multistage-flash/binary process are described. Regeneration is potentially attractive because it recovers waste heat from the turbine exhaust and uses it in the power cycle. However, the pressure drop caused by the introduction of the regenerator decreases the turbine expansion and thus decreases system performance. An innovative approach was taken in the design of the regenerator, which minimized the expected performance degradation of the turbine. The result was that the performance, capital cost, and bus bar electric energy production cost are nearly the same for the processes with and without regeneration. On the other hand, the addition of regeneration has the environmental benefits of substantially reducing heat rejection to the atmosphere and cooling tower makeup and blowdown water requirements. It also increases the temperature of the brine returned to the field for reinjection Title: Advanced Design and Economic Considerations for Commercial Geothermal Power Plants at Heber and Niland, California. Final Report Author: Bechtel Corporation Year: 1977 Two separate studies, involving advanced design and economic considerations for commercial geothermal power plants using liquid-dominated hydrothermal resources, are presented. In the first study, the effects on design, capital cost, and bus bar electric energy production cost caused by an anticipated decline in available geothermal fluid temperature over the lifetime of power plants are described. A two-stage, flashed-steam energy conversion process was used for the conceptual design of the power plants, which operate from the moderate-temperature, low-salinity reservoir at Heber, California. Plants with net capacities of 50, 100, and 200 MWe (net) were investigated. The results show that it is important to include provision for geothermal fluid temperature decline in the design of power plants to prevent loss of electric energy production capability and to reduce bus bar electric energy costs. In the second study, the technical, economic, and environmental effects of adding regeneration to a 50 MWe (net) power plant employing the multistage-flash/binary process are described. Regeneration is potentially attractive because it recovers waste heat from the turbine exhaust and uses it in the power cycle. However, the pressure drop caused by the introduction of the regenerator decreases the turbine expansion and thus decreases system performance. An innovative approach was taken in the design of the regenerator, which minimized the expected performance degradation of the turbine. The result was that the performance, capital cost, and bus bar electric energy production cost are nearly the same for the processes with and without regeneration. On the other hand, the addition of regeneration has the environmental benefits of substantially reducing heat rejection to the atmosphere and cooling tower makeup and blowdown water requirements. It also increases the temperature of the brine returned to the field for reinjection Close

• 8. [Image] Equipment Development Report: Borehole-Fluid Sampling Tool

  	The design and development of a tool for collecting fluid samples from hot, deep geothermal boreholes are discussed. This tool has performed satisfactorily in the field at downhole temperatures of 200/sup ...
  	Citation × Citation Citation Abstract Copy Title: Equipment Development Report: Borehole-Fluid Sampling Tool Author: Archuleta, J.R. Year: 1978 The design and development of a tool for collecting fluid samples from hot, deep geothermal boreholes are discussed. This tool has performed satisfactorily in the field at downhole temperatures of 200/sup 0/C and pressures of 34.5 MPa (5000 psi). Assembly and operating instructions are included Title: Equipment Development Report: Borehole-Fluid Sampling Tool Author: Archuleta, J.R. Year: 1978 The design and development of a tool for collecting fluid samples from hot, deep geothermal boreholes are discussed. This tool has performed satisfactorily in the field at downhole temperatures of 200/sup 0/C and pressures of 34.5 MPa (5000 psi). Assembly and operating instructions are included Close

• 9. [Image] Hot Dry Rock Geothermal Energy Development Project: Cablehead Assembly, Equipment Development Report

  	The development, design, and service history of a multiconductor cablehead capable of operation at 275/sup 0/C and 103 MPa (15,000 psi) are discussed. This high-temperature cablehead has been in service ...
  	Citation × Citation Citation Abstract Copy Title: Hot Dry Rock Geothermal Energy Development Project: Cablehead Assembly, Equipment Development Report Author: Archuleta, J.R. Year: 1978 The development, design, and service history of a multiconductor cablehead capable of operation at 275/sup 0/C and 103 MPa (15,000 psi) are discussed. This high-temperature cablehead has been in service for about 18 months; conclusions drawn from this test period are summarized Title: Hot Dry Rock Geothermal Energy Development Project: Cablehead Assembly, Equipment Development Report Author: Archuleta, J.R. Year: 1978 The development, design, and service history of a multiconductor cablehead capable of operation at 275/sup 0/C and 103 MPa (15,000 psi) are discussed. This high-temperature cablehead has been in service for about 18 months; conclusions drawn from this test period are summarized Close

• 10. [Image] Conceptual Design of Commercial 50 MWe(Net) Geothermal Power Plants at Heber and Niland, California. Final Report

  	The scope of work of this study includes conceptual designs, corresponding capital cost estimates and engineering and construction schedules for two 50 MWe (net) commercial-scale geothermal power plants. ...
  	Citation × Citation Citation Abstract Copy Title: Conceptual Design of Commercial 50 MWe(Net) Geothermal Power Plants at Heber and Niland, California. Final Report Author: Bechtel Corporation Year: 1976 The scope of work of this study includes conceptual designs, corresponding capital cost estimates and engineering and construction schedules for two 50 MWe (net) commercial-scale geothermal power plants. In order to develop and illustrate the concepts involved, the reservoir and site conditions of the geothermal field near Heber, California, which has moderate-temperature low-salinity brine, were used for one of the power plants. The conditions of the field near Niland, California (or the Salton Sea Geothermal Field), which has high-temperature high-salinity brine, were used for the other plant. Both fields are located in the Imperial Valley in Southern California. The two plants give perspective on plant design and capital costs for the range of hydrothermal resources that are of economic interest for electric power generation Title: Conceptual Design of Commercial 50 MWe(Net) Geothermal Power Plants at Heber and Niland, California. Final Report Author: Bechtel Corporation Year: 1976 The scope of work of this study includes conceptual designs, corresponding capital cost estimates and engineering and construction schedules for two 50 MWe (net) commercial-scale geothermal power plants. In order to develop and illustrate the concepts involved, the reservoir and site conditions of the geothermal field near Heber, California, which has moderate-temperature low-salinity brine, were used for one of the power plants. The conditions of the field near Niland, California (or the Salton Sea Geothermal Field), which has high-temperature high-salinity brine, were used for the other plant. Both fields are located in the Imperial Valley in Southern California. The two plants give perspective on plant design and capital costs for the range of hydrothermal resources that are of economic interest for electric power generation Close