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Sample records for east mesa geothermal field

  1. Case history report on East Mesa and Cerro Prieto geothermal fields

    Energy Technology Data Exchange (ETDEWEB)

    Davis, DG.; Sanyal, S.K.

    1979-06-01

    Well log analysis as applied to the geothermal industry is one of the areas of technology in great need of further development. One means of improving log analysis technology is to study case histories of the past uses of log analysis as applied to specific fields. The project described in this report involved case history studies on two well-known geothermal areas in North America: the East Mesa field in California and the Cerro Prieto field in Mexico. Since there was considerably more pertinent material available on East Mesa, a major part of the effort on this project was devoted to studying the East Mesa field. One particular problem that first came to attention when studying the Cerro Prieto data was the difficulty in determining actual formation temperature at the time of logging. Since the temperature can have a significant effect on well log readings, an accurate temperature determination was considered to be important.

  2. Field tests of 2- and 40-tube condensers at the East Mesa Geothermal Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, R.W.; Domingo, N.

    1982-05-01

    Two water-cooled isobutane condensers, one with 2 tubes and one with 40 tubes, were subjected to field tests at the East Mesa Geothermal Test Site to assess relative heat transfer performance in both surface evaporator and direct-contact evaporator modes. The five groups of tests established that field performance was below earlier laboratory-determined levels and that direct-contact evaporator mode performance was poorer than that for the surface evaporator mode. In all test situations, fluted condenser tubes performed better than smooth condenser tubes. Cooling water quality had no significant effect on performance, but brine preflash in the direct-contact mode did promote some relative performance improvement. Important implications of these results for binary geothermal power plants are that (1) working-fluid-side impurities can significantly degrade heat transfer performance of the power plant condensers and (2) provisions for minimizing such impurities may be required.

  3. East Mesa geothermal pump test facility (EMPTF). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Olander, R.G.; Roberts, G.K.

    1984-11-28

    The design, fabrication and installation of a geothermal pump test facility (EMPFT) at the DOE geothermal site at East Mesa, California which is capable of testing 70 to 750 horsepower downwell pumps in a controlled geothermal environment were completed. The facility consists of a skid-mounted brine control module, a 160 foot below test well section, a hydraulic turbine for power recovery, a gantry-mounted hoist for pump handling and a 3-phase, 480 VAC, 1200 amp power supply to handle pump electric requirements. Geothermal brine is supplied to the EMPTF from one of the facility wells at East Mesa. The EMPTF is designed with a great amount of flexibility. The 20-inch diameter test well can accommodate a wide variety of pumps. The controls are interactive and can be adjusted to obtain a full complement of pump operation data, or set to maintain constant conditions to allow long-term testing with a minimum of operator support. The hydraulic turbine allows the EMPTF user to recover approximately 46% of the input pump power to help defray the operating cost of the unit. The hoist is provided for material handling and pump servicing and reduces the equipment that the user must supply for pump installation, inspection and removal.

  4. East Mesa geothermal pump test facility (EMPTF). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Olander, R.G.; Roberts, G.K.

    1984-11-28

    Barber-Nichols has completed the design, fabrication and installation of a geothermal pump test facility at the DOE geothermal site at East Mesa, California which is capable of testing 70 to 750 horsepower downwell pumps in a controlled geothermal environment. The facility consists of a skid-mounted brine control module, a 160 foot below ground test well section, a hydraulic turbine for power recovery, a gantry-mounted hoist for pump handling and a 3-phase, 480 VAC, 1200 amp power supply to handle pump electric requirements. Geothermal brine is supplied to the EMPTF from one of the facility wells at East Mesa. The EMPTF is designed with a great amount of flexibility to attract the largest number of potential users. The 20-inch diameter test well can accommodate a wide variety of pumps. The controls are interactive and can be adjusted to obtain a full complement of pump operation data, or set to maintain constant conditions to allow long-term testing with a minimum of operator support. The hydraulic turbine allows the EMPTF user to recover approximately 46% of the input pump power to help defray the operating cost of the unit. The hoist is provided for material handling and pump servicing and reduces the equipment that the user must supply for pump installation, inspection and removal.

  5. ERDA test facilities, East Mesa Test Site. Geothermal resource investigations, Imperial Valley, California

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    Detailed specifications which must be complied with in the construction of the ERDA Test Facilities at the East Mesa Site for geothermal resource investigations in Imperial Valley, California are presented for use by prospective bidders for the construction contract. The principle construction work includes a 700 gpm cooling tower with its associated supports and equipment, pipelines from wells, electrical equipment, and all earthwork. (LCL)

  6. Session 2: Review of the 500 KW Direct Contact Geothermal Plant at East Mesa

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, Kenneth E.

    1983-12-01

    The concept of a binary power cycle utilizing direct contact heat exchangers was first proposed by Jacobs and Boehm in 1973 for use with geothermal brines. This concept was proposed primarily to overcome difficulties associated with the fouling and scaling nature of many moderate temperature brines. However, thermodynamic analyses and subsequent economic analyses clearly pointed to possible economic advantages over conventional binary cycles even with non-fouling, non-scaling brines. For a direct contact binary power plant to be economically attractive it is necessary that a small pinch point be obtainable so that a maximum amount of power can be obtained per unit mass flow of geothermal brine. Since the working fluid comes in direct contact with the brine it must be immiscible with the brine, low in cost and, if part of it goes into solution in the brine, easily recoverable. In addition, noncondensible gases from the brine must be controlled to limit their effect on condenser pressure. The 500 kWe DCHX test facility installed at East Mesa was designed to evaluate techniques to provide economical operation. The choice of the East Mesa test site as a first location to evaluate the DCHX system placed additional requirements on the system. The brine at East Mesa was at low pressure, requiring the use of downhole pumps. The selection of isobutane as a working fluid required increasing the pressure of the brine. The high amount of dissolved CO{sub 2} in the brine required that it be preflashed to prevent the carryover of CO{sub 2} gas through the turbine and into the condenser which would adversely affect the system performance. All of these problems have been met by the system designer and operator, Barber-Nichols Engineering. Further, problems with isobutane turbine design, supposed state-of-the-art, were encountered and resolved.

  7. Hydraulic Fracture Stimulation Treatments at East Mesa, Well 58-30; Geothermal Reservoir Well Stimulation Program; Experiment 3 and 4

    Energy Technology Data Exchange (ETDEWEB)

    None

    1982-02-01

    The tests reported were part of the DOE Geothermal Reservoir Well Stimulation Program. This East Mesa (Imperial Valley, CA) well was successfully stimulated with two fracture treatments, a dendritic fracture and a planar fracture. The natural flow production of the well increased 114 percent, to 197,900 lb/hr. These tests were among the few successful attempts of this program to increase flow from geothermal production wells. The general belief is that these tests worked OK primarily because the formation was sedimentary rock (similar to rock in most oil and gas wells that have been stimulated successfully. Similar tests in geothermal hard rock reservoirs did not work very well. (DJE 2005)

  8. Planning and design of additional East Mesa Geothermal Test Facilities. Phase 1B. Volume II. Procurement package

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, R.O.

    1976-10-15

    Procurement packages of technical specifications and construction drawings for eleven test facility additions to the ERDA East Mesa Geothermal Component Test Facility are presented. Each of the specifications includes all of the technical requirements needed for procurement and construction starting with Division 2. The information is presented under the following subject headings: injection pump system: 52-2 injection pipeline; control and instrumentation spools; calibration test bench; test pad modifications; test pad piping headers; production and injection wells; well 5-2 modifications; well 8-1 down-hole pump; well 6-1 down-hole pump; and well 8-1 booster pump. (JGB)

  9. Geothermal resource and reservoir investigations of U. S. Bureau of Reclamation leaseholds at East Mesa, Imperial Valley, California

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J.; Apps, J.A.; Benson, S.

    1978-10-01

    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)

  10. Operational and field test results from the 500 kw direct contact pilot plant at East Mesa

    Energy Technology Data Exchange (ETDEWEB)

    Hlinak, A.J.; Lobach, J.L.; Nichols, K.E.

    1981-10-01

    A 500 kw geothermal powerplant utilizing direct contact heat exchange (DCHX) between geothermal brine and an isobutane (IC/sub 4/) working fluid is currently operating at the East Mesa test facility. The pilot plant program was initiated to determine the feasibility of large-scale direct contact heat exchange and associated plant operations. In addition to verifying the design performance of the DCHX itself, test efforts to date have (1) quantified the effect of dissolved gases (primarily CO/sub 2/) transferred from the brine to the IC/sub 4/ loop on the pressure elevation in the unvented power condenser and demonstrated a viable scheme to control this pressure elevation, (2) evaluated the potential of flash extraction and recovery of dissolved IC/sub 4/ from the spent brine, and (3) demonstrated control of fouling in critical components by pretreating the brine with small amounts of a chemical additive (FLOCON 247, Pfizer, Inc.).

  11. Hydraulic-fracture stimulation treatments at East Mesa, Well 58-30. Geothermal-reservoir well-stimulation program

    Energy Technology Data Exchange (ETDEWEB)

    1981-02-01

    East Mesa Well 58-30 was selected for two stimulation treatments: a conventional hydraulic fracture in a deep, low permeability interval, and a dendritic fracture in a shallow, high permeability interval of completion. The well selection, pre-stimulation evaluation, fracture treatment design, and post-stimulation evaluation are presented.

  12. Preliminary evaluation of fluid chemistry in the East Mesa KGRA

    Energy Technology Data Exchange (ETDEWEB)

    Hoagland, J.R.

    1976-10-04

    One of the major problems needing consideration when bringing a geothermal field into production is the anticipation and control of mineral precipitation in both the producing formations and production equipment. Prediction of the chemical interactions between natural multicomponent thermal fluids and the minerals comprising a producing formation can be accomplished by the study of equilibrium models approximating the natural system. Models are constructed from theoretically and experimentally derived thermodynamic data for the involved minerals and aqueous species. This equilibrium modeling approach was applied to the rock-water system at the East Mesa geothermal area in the Imperial Valley of California. Results of petrographic and fluid analyses are given. (JGB)

  13. 'Bread Loaf' Mesa East of Phlegra Montes

    Science.gov (United States)

    2002-01-01

    [figure removed for brevity, see original site] An isolated mesa east of the Phlegra Montes in northeastern Elysium Planitia has a cracked surface that, combined with its overall shape, gives the appearance of a giant loaf of bread. Other mesas with similar surfaces are found in the area, suggesting that at one time these mesas were part of a continuous layer of material. It is likely that at that time, some process caused the graben-like cracks to form. Later erosion of the cracked layer left only the isolated mesas seen in the THEMIS image. One clue that supports this scenario is the presence of many filled and eroded craters throughout the scene but no fresh ones. One way to produce this landscape begins with an ancient and heavily cratered surface that subsequently is buried by some other material. If this overburden was stripped off relatively recently, not enough time would have passed to allow for a new population of fresh craters to be produced. The result would be a landscape with isolated mesas of younger material on top of an ancient, cratered surface.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey

  14. Imperial County geothermal development annual meeting: summary

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    All phases of current geothermal development in Imperial County are discussed and future plans for development are reviewed. Topics covered include: Heber status update, Heber binary project, direct geothermal use for high-fructose corn sweetener production, update on county planning activities, Brawley and Salton Sea facility status, status of Imperial County projects, status of South Brawley Prospect 1983, Niland geothermal energy program, recent and pending changes in federal procedures/organizations, plant indicators of geothermal fluid on East Mesa, state lands activities in Imperial County, environmental interests in Imperial County, offshore exploration, strategic metals in geothermal fluids rebuilding of East Mesa Power Plant, direct use geothermal potential for Calipatria industrial Park, the Audubon Society case, status report of the Cerro Prieto geothermal field, East Brawley Prospect, and precision gravity survey at Heber and Cerro Prieto geothermal fields. (MHR)

  15. Simulated heat-exchanger tubes: DOE Geothermal Test Facility, East Mesa, California. Corrosion test report. [Allegheny-Ludlum Alloy 29-4 and Alloy 29-4C

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, P.F. II; Anliker, D.M.

    1982-11-01

    A 1032-hr corrosion test was made of two geothermal heat exchanger materials, Allegheny-Ludlum Alloy 29-4 and Alloy 29-4C. Coupons of the two metals were exposed under conditions simulating flow in a geothermal heat exchanger tube. Continuous flow and cyclic exposure tests were made. No signs of localized corrosion were observed in either the base metal, tube weld seam, or heat affected zone. Most coupons showed statistically insignificant weight change. A corrosion rate of less than 0.5 mil/yr is indicated. No significant difference in the performance of the two alloys is reported. (LEW)

  16. Near-surface groundwater responses to injection of geothermal wastes

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, S.C.

    1984-06-01

    This report assesses the feasibility of injection as an alternative for geothermal wastewater disposal and analyzes hydrologic controls governing the upward migration of injected fluids. Injection experiences at several geothermal developments are presented including the following: Raft River Valley, Salton Sea, East Mesa, Otake, Hatchobaru, and Ahuachapan geothermal fields.

  17. Compartmentalization of the Coso East Flank Geothermal Field Imaged by 3-D Full-tensor MT Inversion

    Science.gov (United States)

    Lindsey, Nathaniel J.; Kaven, Joern Ole; Davatzes, Nicholas; Newman, Gregory A.

    2016-11-01

    Previous magnetotelluric (MT) studies of the high-temperature Coso geothermal system in California identified a subvertical feature of low resistivity (2 - 5 Ohm-m) and appreciable lateral extent (>1 km) in the producing zone of the East Flank field. However, these models could not reproduce gross 3-D effects in the recorded data. We perform 3-D full-tensor inversion and retrieve a resistivity model that out-performs previous 2-D and 3-D off-diagonal models in terms of its fit to the complete 3-D MT dataset as well as the degree of modeling bias. Inclusion of secondary Zxx and Zyy data components leads to a robust east-dip (60o) to the previously identified conductive East Flank reservoir feature, which correlates strongly with recently mapped surface faults, downhole well temperatures, 3-D seismic reflection data, and local microseismicity. We perform synthetic forward modeling to test the best fit dip of this conductor using the response at a nearby MT station. We interpret the dipping conductor as a fractured and fluidized compartment, which is structurally-controlled by an unmapped blind East Flank fault zone.

  18. Compartmentalization of the Coso East Flank geothermal field imaged by 3-D full-tensor MT inversion

    Science.gov (United States)

    Lindsey, Nathaniel J.; Kaven, Joern Ole; Davatzes, Nicholas; Newman, Gregory A.

    2017-02-01

    Previous magnetotelluric (MT) studies of the high-temperature Coso geothermal system in California identified a subvertical feature of low resistivity (2-5 Ohm m) and appreciable lateral extent (>1 km) in the producing zone of the East Flank field. However, these models could not reproduce gross 3-D effects in the recorded data. We perform 3-D full-tensor inversion and retrieve a resistivity model that out-performs previous 2-D and 3-D off-diagonal models in terms of its fit to the complete 3-D MT data set as well as the degree of modelling bias. Inclusion of secondary Zxx and Zyy data components leads to a robust east-dip (60†) to the previously identified conductive East Flank reservoir feature, which correlates strongly with recently mapped surface faults, downhole well temperatures, 3-D seismic reflection data, and local microseismicity. We perform synthetic forward modelling to test the best-fit dip of this conductor using the response at a nearby MT station. We interpret the dipping conductor as a fractured and fluidized compartment, which is structurally controlled by an unmapped blind East Flank fault zone.

  19. Exploration of Ulumbu geothermal field, Flores-east nusa tenggara, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Sulasdi, Didi

    1996-01-26

    This paper describes the progress made in developing geothermal resources at Ulumbu Flores, Indonesia for utilization mini geothermal power generation. Two deep exploratory wells drilling drilled by PLN confirmed the existence of the resources. The well measurement carried out during drilling and after completion of the well indicated that the major permeable zone at around 680 m depth and that this zone is a steam cap zone, which is likely to produce high enthalpy steam. The above information indicates that well ULB-01 will produce a mass flow at least 40 tonnes per hour, which will ensure a 3 MW (E) Ulumbu mini geothermal power plant.

  20. Deformation study of Kamojang geothermal field

    Science.gov (United States)

    Ramdhani, B. D.; Meilano, I.; Sarsito, D. A.

    2017-07-01

    GPS has proven to be an indispensable tool in the effort to understand crust deformation before, during, and after the big earthquake events through data analysis and numerical simulation. The development of GPS technology has been able to prove as a method for the detection of geothermal activity that related to deformation. Furthermore, the correlation of deformation and geothermal activity are related to the analysis of potential hazards in the geothermal field itself. But unfortunately, only few GPS observations established to see the relationship of tectonic and geothermal activity around geothermal energy area in Indonesia. This research will observe the interaction between deformation and geothermal sources around the geothermal field Kamojang using geodetic GPS. There are 4 campaign observed points displacement direction to north-east, and 2 others heading to south-east. The displacement of the observed points may have not able proven cause by deformation of geothermal activity due to duration of observation. Since our research considered as pioneer for such investigation in Indonesia, we expect our methodology and our findings could become a starter for other geothermal field cases in Indonesia.

  1. Imperial County geothermal development. Quarterly report, April 1, 1980-June 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    Three areas are reported: Geothermal Administration, Geothermal Planning; and other Geothermal Activities. Geothermal Administration addresses the status of the Imperial Valley Environmental Project (IVEP) transfer, update of the Geothermal Resource Center, and findings of Geothermal field inspections. Field inspections will cover the four new wells drilled by Magma at the Salton Sea in preparation for 28 MW power plant, the progress at Sperry at East Mesa, and the two on-line power plants in East Mesa and North Brawley. Evaluation of cooperative efforts will cover the Geothermal Subsidence Detection Network Resurvey, Master EIR for the Salton Sea and the Annual Imperial County Geothermal meeting. The status of Geothermal development throughout the County will cover existing proposed facilities. The summary of the Geothermal meeting (Appendix A) will also provide the status of several projects. Geothermal Planning addresses the EIR Notice of Exemption from CEQA, progress on the Master EIR for the Salton Sea, and the EIR for Phillips Petroleum for 6 exploratory wells in the Truckhaven area. Other Geothermal Activity addresses the Department of Energy Region IX meeting hosted by Imperial County, the Annual Imperial County Geothermal meeting, Class II-1 geothermal hazardous waste disposal siting study, and Imperial County Geothermal Direct Heat Study.

  2. Geothermal Field Developments in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Hirakawa, Seiichi

    1983-12-15

    The present situation of the geothermal field developments in Japan is such that eight geothermal power stations are being operated, while there are sill many geothermal areas to be explored. Up to this day, the target of geothermal exploration has mainly been the areas by surface geological survey and the existing geothermal reservoirs are located not deeper than 1,500m depth. Recent geothermal energy development shows a trend from the study on vapor dominated of liquid dominated hydrothermal resources in shallow zones to that on hydrothermal resources in deeper zones. Exploration wells of 3,000m depth class have been drilled in Japan.

  3. Test results from the 500 kW direct contact pilot plant at East Mesa

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, K.E.; Olander, R.G.; Lobach, J.L.

    1980-09-01

    A 500 kW power plant utilizing direct contact heat exchange (DCHX) between the geothermal brine and the isobutane (IC/sub 4/) working fluid is being operated at the East Mesa test facility. The power plant incorporates a 40-inch-diameter direct-contactor approximately 35 feet tall. The purpose of the pilot plant is to determine the feasibility of large-scale direct-contact heat exchange and power plant operation with the DCHX. The binary cycle offers higher conversion factors (heat energy transformed to electrical energy) than the flashed steam approach for geothermal brines in the 300 to 400/sup 0/F range and preliminary results indicate the DCHX system may have higher performance than the conventional tube-and-shell binary approach. This performance advantage results from the absence of any fouling and the very close pinch temperatures achieved in the DCHX itself. The baseline performance tests for the plant were completed in January 1980. The results of these tests and follow-on testing are covered.

  4. Reservoir Simulation on the Cerro Prieto Geothermal Field: A Continuing Study

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda, M.; Marquez, R.; Arellano, V.; Esquer, C.A.

    1983-12-15

    The Cerro Prieto geothermal field is a liquid-dominated geothermal reservoir of complex geological and hydrological structure. It is located at the southern end of the Salton-Mexicali trough which includes other geothermal anomalies as Heber and East Mesa. Although in 1973, the initial power plant installed capacity was 75 MW of electrical power, this amount increased to 180 MW in 1981 as field development continued. It is expected to have a generating capacity of 620 MW by the end of 1985, when two new plants will be completely in operation. Questions about field deliverability, reservoir life and ultimate recovery related to planned installations are being presently asked. Numerical modeling studies can give very valuable answers to these questions, even at the early stages in the development of a field. An effort to simulate the Cerro Prieto geothermal reservoir has been undergoing for almost two years. A joint project among Comision Federal de Electricidad (CFE), Instituto de Investigaciones Electricas (IIE) and Intercomp of Houstin, Texas, was created to perform reservoir engineering and simulation studies on this field. The final project objective is tosimulate the behavior of the old field region when production from additional wells located in the undeveloped field zones will be used for feeding the new power plants.

  5. Geothermal exploration technology. Annual report, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    Progress is reported on the following programs: electrical and electromagnetic computer modeling techniques; minicomputer for in-field processing of magnetotelluric data; superconducting thin-film gradiometer and magnetometers for geophysical applications; magnetotellurics with SQUID magnetometers; controlled-source electromagnetic system; geothermal seismic field system development; Klamath Basin geothermal resource and exploration technique evaluation; Mt. Hood geothermal resource evaluation; East Mesa seismic study; seismological studies at Cerro Prieto; self-potential studies at Cerro Prieto; resistivity studies at Cerro Prieto; magnetotelluric survey at Cerro Prieto; and precision gravity studies at Cerro Prieto. (MHR)

  6. Geothermal structure of Australia's east coast basins

    Science.gov (United States)

    Danis, C. R.; O'Neill, C.

    2010-12-01

    The east coast sedimentary basins of Australia formed on an active margin of eastern Gondwana, and constitute an important hydrocarbon resource. The 1600km long Sydney-Gunnedah-Bowen Basin (SGBB) is largest east coast basin system, with thick Permian to Jurassic sedimentary successions overlying Palaeozoic basement rocks. The SGBB has been the focus of renewed geothermal exploration interest, however, the thermal state and geothermal potential of the system is largely unconstrained. Geothermal exploration programs require an accurate estimate of subsurface temperature information, in addition to favourable geology, to make informed decisions on potential targe developments. Primarily temperature information comes from downhole measurements, generally non-equilibrated, which are traditionally extrapolated to depth, however such extrapolation does not take into account variations in geological structure or thermal conductivity. Here we import deep 3D geological models into finite element conduction simulations, using the code Underworld, to calculate the deep thermal structure of the basin system. Underworld allows us to incorporate complex, detailed geological architecture models, incorporating different material properties for different layers, with variable temperature and depth-dependent properties. We adopt a fixed top boundary temperature on a variable topographic surface, and vary the bottom surface boundary condition, to converge of models which satisfy equilibrated downhole temperature measurement constraints. We find coal plays an important role in insulating sedimentary basins. Heat refracts around the coal interval and produces elevated temperatures beneath thick sediments, especially where thick coal intervals are present. This workflow has been formalized into an Underworld geothermal model library, enabling model centric computational workflows. Using the imported model architecture from the geology, data can be continuously updated and added to the

  7. Experimental geothermal research facilities study (Phase O). Final report No. 26405-6001-RU-00

    Energy Technology Data Exchange (ETDEWEB)

    1974-12-31

    This study focuses on identification of a representative liquid-dominated geothermal reservoir of moderate temperature and salinity, preliminary design of an appropriate energy conversion system, identification of critical technology and planning for the implementation of experimental facilities. Results of Phase O of the project are reported in two volumes. Volume II presents detailed results of studies and analyses arranged in nine appendices including the final report by a subcontractor on the study. The specific appendices are: Appendix A: Geothermal Resources of the Western United States; Appendix B: Site Selection Process and the East Mesa Geothermal Field; Appendix C: East Mesa Geothermal Field Reservoir Characteristics; Appendix D: Advisor's Views and Comments; Appendix E: Thermodynamic Analyses; Appendix F: Material and Corrosion Factors; Appendix G: Preliminary Reliability/Maintainability Analyses; Appendix H: Environmental Impact Analysis Guidelines; and Appendix I: Report to the National Science Foundation/TRW Systems Group by Rogers Engineering Company, Inc., San Francisco, California.

  8. PROSPECTS OF GEOTHERMAL RESOURCES DEVELOPMENT FOR EAST CISCAUCASIA

    Directory of Open Access Journals (Sweden)

    A. B. Alkhasov

    2013-01-01

    Full Text Available Abstract. Work subject. Aim. The Northern Caucasus is one of the prospective regions for development of geothermal energy.The hydrogeothermal resources of the only East Ciscaucasian Artesian basin are estimated up to 10000 MW of heat and 1000 MW of electric power. For their large-scale development it is necessary to built wells of big diameter and high flow rate involving huge capital investments. Reconstruction of idle wells for production of thermal water will allow to reduce capital investments for building of geothermal power installations. In the East Ciscaucasian Artesian basin there are a lot of promising areas with idle wells which can be converted for production of thermal water. The purpose of work is substantiation possibility of efficient development of geothermal resources of the Northern Caucasus region using idle oil and gas wells.Methods. The schematic diagram is submitted for binary geothermal power plant (GPP with use of idle gas-oil wells where the primary heat carrier in a loop of geothermal circulation system is used for heating and evaporation of the low-boiling working agent circulating in a secondary contour of steam-power unit. Calculations are carried out for selection of the optimum parameters of geothermal circulation system for obtaining the maximum useful power of GPP. The thermodynamic analysis of low-boiling working agents is made. Development of medial enthalpy thermal waters in the combined geothermal-steam-gas power installations is offered where exhaust gases of gas-turbine installation are used for evaporation and overheat of the working agent circulating in a contour of GPP. Heating of the working agent in GPP up to the temperature of evaporation is carried out by thermal water.Results. The possibility of efficient development of geothermal resources of the Northern Caucasus region by construction of binary geothermal power plants using idle oil and gas wells is substantiated. The capacities and the basic

  9. Geothermal emissions data base, Wairakei geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, S.R. (comp.)

    1978-04-01

    A database subset on the gaseous emissions from the Wairakei geothermal field is presented. Properties and states of the reservoir fluid such as flow rates, wellhead pressure, and enthalpy are included in the file along with the well name and constituent measurement. This subset is the result of an initial screening of the data covering 1965 to 1971, and new additions will be appended periodically to the file. The data is accessed by a database management system as are all other subsets in the file. Thereby, one may search the database for specific data requirements and print selective output. For example, one may wish to locate reservoir conditions for cases only when the level of the constituent exceeded a designated value. Data output is available in the form of numerical compilations such as the attached, or graphical displays disposed to paper, film or magnetic tape.

  10. Two-Phase Flow in Geothermal Wells: Development and Uses of a Good Computer Code

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz-Ramirez, Jaime

    1983-06-01

    A computer code is developed for vertical two-phase flow in geothermal wellbores. The two-phase correlations used were developed by Orkiszewski (1967) and others and are widely applicable in the oil and gas industry. The computer code is compared to the flowing survey measurements from wells in the East Mesa, Cerro Prieto, and Roosevelt Hot Springs geothermal fields with success. Well data from the Svartsengi field in Iceland are also used. Several applications of the computer code are considered. They range from reservoir analysis to wellbore deposition studies. It is considered that accurate and workable wellbore simulators have an important role to play in geothermal reservoir engineering.

  11. M.E.S.A, not Just a Seat at the Table: a Chicano Geology Student's Experience with Investigative Field Research

    Science.gov (United States)

    Ponce-Zepeda, M. M.

    2011-12-01

    The MESA (math, engineering, science achievement) program in California engages educationally disadvantaged students, primarily minority groups, providing the opportunity to excel in math and science and graduate with math-based degrees. MESA at East Los Angeles Community College selected me, a returning 24 year-old Chicano student, for the SCEC (Southern California Earthquake Center) summer internship at Utah State University (USU). The project coordinators assigned me to a group with three other undergraduate geology students from across the continent and from a variety of socioeconomic backgrounds to investigate geothermal systems in the Salton Trough and northern Utah. The peer-driven field work transformed student to investigator by forcing each participant to be responsible for the success of the entire group. In this environment, I rose to expectations along with my fellow interns managing a detailed field notebook, sampling, planning routes, level logger maintenance, and x-ray diffractometer analysis interpretation, among other things. Mentorship from and challenges proposed by the USU project advisor further built on this scaffolding of field experience. First hand fieldwork provides a battery of beneficial skills that many undergraduate geology students, especially at the two- year college level, rarely get an opportunity to participate in. The advantage of including non-traditional students from two- year colleges allows for a dynamic research network nationwide. Key sample collection by the East Los Angeles College (ELAC) Geology Club, a student- run club at an inner city community college, facilitated ongoing examination by collecting mud samples from gryphons and mudpots in the Salton Trough and testing temperature, pH levels, electrical conductivity, and total dissolved solids in the field. The samples were sent back to students at USU for further analysis. This collaborative effort is symbiotic as sharing the sampling responsibility allowed USU to

  12. Integrated Geophysical Studies in the East-Indian Geothermal Province

    Science.gov (United States)

    Baranwal, V. C.; Sharma, S. P.

    2006-01-01

    Integrated geophysical surveys using vertical electrical sounding (VES), very low frequency (VLF) EM, radiation counting, total magnetic field and self-potential (SP) measurements are carried out to characterize the geothermal area around a hot spring in the Nayagarh district, Orissa, India that lies in the East Indian geothermal province. The study was performed to delineate the fracture pattern, contaminated groundwater movement and possible heating source. VES interpretations suggest a three- to four-layer structure in the area. Resistivity survey near the hot spring suggests that weathered and fractured formations constitute the main aquifer system and extend to 60 m depth. Current flow measured at various electrode separations normalized by the applied voltage suggests that fractures extend to a greater depth. Detailed VLF study shows that fractures extend beyond 70 m depth. VLF anomaly has also very good correlation with the total magnetic field measured along the same profiles. Study results suggest that a gridded pattern of VLF survey could map the underground conductive fracture zones that can identify the movement of contaminated groundwater flow. Therefore, precautionary measures can be taken to check further contamination by delineating subsurface conducting structures. Self potential (SP) measured over the hot spring does not show a large anomaly in favor of the presence of a sulphide mineral body. A small positive (5 15mV) SP anomaly is measured which may be streaming potential due to subsurface fluid flow. A high radiation is measured about four kilometers from the hot spring, suggesting possible radiogenic heating. However, the exact nature of the heating source and its depth is not known in the area. Deep resistivity followed by a magneto-telluric survey could reveal the deeper structures.

  13. Maximum Magnitude and Probabilities of Induced Earthquakes in California Geothermal Fields: Applications for a Science-Based Decision Framework

    Science.gov (United States)

    Weiser, Deborah Anne

    Induced seismicity is occurring at increasing rates around the country. Brodsky and Lajoie (2013) and others have recognized anthropogenic quakes at a few geothermal fields in California. I use three techniques to assess if there are induced earthquakes in California geothermal fields; there are three sites with clear induced seismicity: Brawley, The Geysers, and Salton Sea. Moderate to strong evidence is found at Casa Diablo, Coso, East Mesa, and Susanville. Little to no evidence is found for Heber and Wendel. I develop a set of tools to reduce or cope with the risk imposed by these earthquakes, and also to address uncertainties through simulations. I test if an earthquake catalog may be bounded by an upper magnitude limit. I address whether the earthquake record during pumping time is consistent with the past earthquake record, or if injection can explain all or some of the earthquakes. I also present ways to assess the probability of future earthquake occurrence based on past records. I summarize current legislation for eight states where induced earthquakes are of concern. Unlike tectonic earthquakes, the hazard from induced earthquakes has the potential to be modified. I discuss direct and indirect mitigation practices. I present a framework with scientific and communication techniques for assessing uncertainty, ultimately allowing more informed decisions to be made.

  14. Characteristic of geothermal fluid at East Manggarai, Flores, East Nusa Tenggara

    Science.gov (United States)

    Iqbal, Mochamad; Herdianita, Niniek Rina; Risdianto, Dikdik

    2016-09-01

    The research area is located in East Manggarai and its surrounding area, Flores. In the study area there are two geothermal systems, i.e. Mapos geothermal system which is associated with Anak Ranakah volcano and Rana Masak geothermal systems which is associated with Watuweri volcano. The difference within these systems is shown by the relative content of conservative elements of Cl, Li and B. Geothermal surface manifestations in Mapos include 4 hot springs having temperatures of 34,3-51,4°C and bicarbonate and sulphate-bicarbonate waters; the discharge area in Rana Masak consist of 3 hot springs with temperatures of 38-46,6°C and chloride and chloride-bicarbonate water. Stable isotopes δ18O and δD analyses showed that the geothermal fluid derived from meteoric water. The Mapos geothermal system is a high temperature system having reservoir temperature of 250-270°C with natural heat loss of 230 kW. The Rana Masak geothermal system is a low temperature system having reservoir temperature of 120-140°C with natural heat loss of 120 kW.

  15. Klamath Falls geothermal field, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, P.J.; Culver, G.; Lund, J.W.

    1989-09-01

    Klamath Falls, Oregon, is located in a Known Geothermal Resource Area which has been used by residents, principally to obtain geothermal fluids for space heating, at least since the turn of the century. Over 500 shallow-depth wells ranging from 90 to 2,000 ft (27 to 610 m) in depth are used to heat (35 MWt) over 600 structures. This utilization includes the heating of homes, apartments, schools, commercial buildings, hospital, county jail, YMCA, and swimming pools by individual wells and three district heating systems. Geothermal well temperatures range from 100 to 230{degree}F (38 to 110{degree}C) and the most common practice is to use downhole heat exchangers with city water as the circulating fluid. Larger facilities and district heating systems use lineshaft vertical turbine pumps and plate heat exchangers. Well water chemistry indicates approximately 800 ppM dissolved solids, with sodium sulfate having the highest concentration. Some scaling and corrosion does occur on the downhole heat exchangers (black iron pipe) and on heating systems where the geo-fluid is used directly. 73 refs., 49 figs., 6 tabs.

  16. A database for the geysers geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Bodvarsson, G.S.; Cox, B.L.; Fuller, P.; Ripperda, M.; Tulinius, H.; Witherspoon, P.A.; Goldstein, N.; Flexser, S.; Pruess, K. (Lawrence Berkeley Lab., CA (USA)); Truesdell, A. (Geological Survey, Menlo Park, CA (USA))

    1989-09-01

    This document contains graphs of data collected from Geysers Geothermal Field. These graphs display data concerning wellhead pressure and degrees of super heat from 1968 to 1988 in Appendix B; injection rate and cumulative injection rate in Appendix C. 255 figs. (FSD)

  17. Geothermal Field Development in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, Hector Alonso

    1983-12-15

    Mexico is a Country characterized by its diversified means of Power Gerneration. Actual installed capacity is almost 19000 MW, of which 205 MW corresponds to Geothermal Plants, that is, 180 MW in Cerro Prieto and 25 MW of Portable Plants in Los Azufres. To date, 346 area with exploitation possibilites, are known. They are mainly distributed along the Volcanic Belt where the most prominent are, Los Azufres, La Primavera, Los Humeros, Ixtlan De Los Hervores and Los Negritos, among others. Proved reserves are 920 MW, and the accessible resource base are 4600 MW identified and 6000 MW undiscovered. The long range construction studies intends to achieve a total installed capacity of 100000 MW, by the end of this century, including 2000 MW Geothermal, through conventional and Portable Plants. It is not a definite program but a development strategy. The carrying out of a definite program, will depend upon the confirmation of Hypothesis made in previous studies, and the economic decisions related to the financial sources availability, and techologies to be used in the future as well.

  18. Cerro Prieto geothermal field: exploration during exploitation

    Energy Technology Data Exchange (ETDEWEB)

    1982-07-01

    Geological investigations at Momotombo included photogeology, field mapping, binocular microscope examination of cuttings, and drillhole correlations. Among the geophysical techniques used to investigate the field sub-structure were: Schlumberger and electromagnetic soundings, dipole mapping and audio-magnetotelluric surveys, gravity and magnetic measurements, frequency domain soundings, self-potential surveys, and subsurface temperature determinations. The geochemical program analyzed the thermal fluids of the surface and in the wells. The description and results of exploration methods used during the investigative stages of the Momotombo Geothermal Field are presented. A conceptual model of the geothermal field was drawn from the information available at each exploration phase. The exploration methods have been evaluated with respect to their contributions to the understanding of the field and their utilization in planning further development.

  19. Geothermal emissions data base: Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, S.R. (comp.)

    1978-04-01

    A new database subset on the gaseous emissions from the Cerro Prieto geothermal field is presented. Properties and states of the reservoir fluid such as flow rates, wellhead pressure, and enthalpy are included in the file along with the well name and constituent measurement. This subset is the result of an initial screening of the data covering 1967 to 1969, and new additions will be appended periodically to the file. The data are accessed by a database management system as are all other subsets in the file. Thereby, one may search the database for specific data requirements and print selective output. For example, one may wish to locate reservoir conditions for cases only when the level of the constituent exceeded a designated value. Data output is available in the form of numerical compilations such as the attached, or graphical displays disposed to paper, film, or magnetic tape.

  20. Reservoir assessment of The Geysers Geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, R.P.; Chapman, R.H.; Dykstra, H.

    1981-01-01

    Big Sulphur Creek fault zone, in The Geysers Geothermal field, may be part of a deep-seated, wrench-style fault system. Hydrothermal fluid in the field reservoir may rise through conduits beneath the five main anomalies associated with the Big Sulphur Creek wrench trend. Some geophysical anomalies (electrical resistivity and audio-magnetotelluric) evidently are caused by the hot water geothermal field or zones of altered rocks; others (gravity, P-wave delays, and possibly electrical resistivity) probably respresent the underlying heat source, a possible magma chamber; and others (microearthquake activity) may be related to the steam reservoir. A large negative gravity anomaly and a few low-resistivity anomalies suggest areas generally favorable for the presence of steam zones, but these anomalies apparently do not directly indicate the known steam reservoir. At the current generating capacity of 930 MWe, the estimated life of The Geysers Geothermal field reservoir is 129 years. The estimated reservoir life is 60 years for the anticipated maximum generating capacity of 2000 MWe as of 1990. Wells at The Geysers are drilled with conventional drilling fluid (mud) until the top of the steam reservoir is reached; then, they are drilled with air. Usually, mud, temperature, caliper, dual induction, and cement bond logs are run on the wells.

  1. Direct application of West Coast geothermal resources in a wet-corn-milling plant. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-03-01

    The engineering and economic feasibility of using the geothermal resources in East Mesa, California, in a new corn processing plant is evaluated. Institutional barriers were also identified and evaluated. Several alternative plant designs which used geothermal energy were developed. A capital cost estimate and rate of return type of economic analysis were performed to evaluate each alternative. (MHR)

  2. Geothermal Reservoir Characterization for Steam Field Management in Kamojang Geothermal Field-West Java

    Directory of Open Access Journals (Sweden)

    Z. Abidin

    2009-01-01

    Full Text Available Kamojang is the first geothermal field in Indonesia with a vapor dominated system reservoir. Kamojang has been exploited for over 20 years producing about 1100 tons/hour of steam which is equivalent to 140 Mwe electricity energy. This research is aimed to study the reservoir character after 20 years of exploitation and to investigate the effect of reinjection as a artificial recharge for steam input in the future and also the nature of secondary processes in the reservoir using isotope geochemistry tools. The research is conducted by natural isotopes (18O, 2H and 3H analysis of many sources of water (meteoric, cold spring, fumaroles and shallow groundwater in the surrounding of Kamojang field and also fluid reservoir to establish fluid reservoir origins and isotopic composition. Gas analysis and isotopes monitoring on the 25 production wells have been conducted every 2-3 years intervals for more than 10 years to investigate the effect of exploitation to the reservoir performance. Tritium radiotracer test with 370 GBq (10 Ci activity was conducted at the KMJ 15 reinjection well to determine qualitatively and quantitatively the flow of reinjection water to its surrounding producing well (KMJ 11, 14, 17, 18, 26, 17 and 30. Data interpretation and evaluation to determine reinjection water mass recovery and cooling prediction modeling were conducted using ICEBOX program package (TRINV and TRCOOL. Interpretation and evaluation of data concluded that reservoir fluid of Kamojang geothermal field was originated from meteoric water which infiltrated through fault structures at elevation of 1350 m –1650 m above sea level. There is no evidence that the fluid was originated from magmatic water. Reservoir fluid moved both laterally and vertically (deep fluid with lateral fluid movement from west to the east. The isotope data analysis indicated there is water entry in west-northwest reservoir boundary. Water entry gradually moved from northwest to the

  3. Strain rate orientations near the Coso Geothermal Field

    Science.gov (United States)

    Ogasa, N. T.; Kaven, J. O.; Barbour, A. J.; von Huene, R.

    2016-12-01

    Many geothermal reservoirs derive their sustained capacity for heat exchange in large part due to continuous deformation of preexisting faults and fractures that permit permeability to be maintained. Similarly, enhanced geothermal systems rely on the creation of suitable permeability from fracture and faults networks to be viable. Stress measurements from boreholes or earthquake source mechanisms are commonly used to infer the tectonic conditions that drive deformation, but here we show that geodetic data can also be used. Specifically, we quantify variations in the horizontal strain rate tensor in the area surrounding the Coso Geothermal Field (CGF) by analyzing more than two decades of high accuracy differential GPS data from a network of 14 stations from the University of Nevada Reno Geodetic Laboratory. To handle offsets in the data, from equipment changes and coseismic deformation, we segment the data, perform a piecewise linear fit and take the average of each segment's strain rate to determine secular velocities at each station. With respect to North America, all stations tend to travel northwest at velocities ranging from 1 to 10 mm/yr. The nearest station to CGF shows anomalous motion compared to regional stations, which otherwise show a coherent increase in network velocity from the northeast to the southwest. We determine strain rates via linear approximation using GPS velocities in Cartesian reference frame due to the small area of our network. Principal strain rate components derived from this inversion show maximum extensional strain rates of 30 nanostrain/a occur at N87W with compressional strain rates of 37nanostrain/a at N3E. These results generally align with previous stress measurements from borehole breakouts, which indicate the least compressive horizontal principal stress is east-west oriented, and indicative of the basin and range tectonic setting. Our results suggest that the CGF represents an anomaly in the crustal deformation field, which

  4. Integrated model of the shallow and deep hydrothermal systems in the East Mesa area, Imperial Valley, California

    Energy Technology Data Exchange (ETDEWEB)

    Riney, T.D.; Pritchett, J.W.; Rice, L.F.

    1982-01-01

    Geological, geophysical, thermal, petrophysical and hydrological data available for the East Mesa hydrothermal system that are pertinent to the construction of a computer model of the natural flow of heat and fluid mass within the system are assembled and correlated. A conceptual model of the full system is developed and a subregion selected for quantitative modeling. By invoking the Boussinesq approximation, valid for describing the natural flow of heat and mass in a liquid hydrothermal system, it is found practical to carry computer simulations far enough in time to ensure that steady-state conditions are obtained. Initial calculations for an axisymmetric model approximating the system demonstrate that the vertical formation permeability of the deep East Mesa system must be very low (k/sub v/ approx. 0.25 to 0.5 md). Since subsurface temperature and surface heat flow data exhibit major deviations from the axisymmetric approximation, exploratory three-dimensional calculations are performed to assess the effects of various mechanisms which might operate to produce such observed asymmetries. A three-dimensional model evolves from this iterative data synthesis and computer analysis which includes a hot fluid convective source distributed along a leaky fault radiating northward from the center of the hot spot and realistic variations in the reservoir formation properties.

  5. Los Humeros geothermal field, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Upton, P.S.

    1997-12-31

    Studies done to evaluate a low permeability-high enthalpy reservoir are reported in this paper. The main mechanism of well production in Los Humeros seems to be strongly related to a fracture network with a low matrix permeability. Under this condition there is a preferential steam flow to wells which is not easy to handle with a primary porosity model even though an element refinement is used. Here, the relative permeabilities are important because the subcooled non-perturbed state is close to the thermodynamic saturation line. Reservoir assessment results using a single porosity model have not been able to reproduce the average production enthalpy measured at the field and seem to be not good enough to represent the heat and transport phenomena occurring there. On the other hand, small scale problems using a double porosity model and similar initial conditions from Los Humeros apparently give a better fit to the production enthalpy. Volumetric assessment of the resource shows a generation capacity of the field of the order of the 120 MWe for an exploitation period of 20 years.

  6. Geothermal Resource Analysis and Structure of Basin and Range Systems, Especially Dixie Valley Geothermal Field, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    David Blackwell; Kenneth Wisian; Maria Richards; Mark Leidig; Richard Smith; Jason McKenna

    2003-08-14

    Publish new thermal and drill data from the Dizie Valley Geothermal Field that affect evaluation of Basin and Range Geothermal Resources in a very major and positive way. Completed new geophysical surveys of Dizie Valley including gravity and aeromagnetics and integrated the geophysical, seismic, geological and drilling data at Dizie Valley into local and regional geologic models. Developed natural state mass and energy transport fluid flow models of generic Basin and Range systems based on Dizie Valley data that help to understand the nature of large scale constraints on the location and characteristics of the geothermal systems. Documented a relation between natural heat loss for geothermal and electrical power production potential and determined heat flow for 27 different geothermal systems. Prepared data set for generation of a new geothermal map of North American including industry data totaling over 25,000 points in the US alone.

  7. Geothermal research. Innovative geothermal probe field for an Art Nouveau villa; Geothermieforschung. Innovatives Erdwaermesondenfeld fuer Jugendstilvilla

    Energy Technology Data Exchange (ETDEWEB)

    Buechner, Ute; Dworrak, Matthias C. [FITR - Forschungsinstitut fuer Tief- und Rohrleitungsbau gemeinnuetzige GmbH, Weimar (Germany)

    2010-07-01

    The Weimarer Forschungsinstitut fuer Tief- und Rohrleitungsbau (FITR) is seated in a historical Art Nouveau Villa owned by the Max-Zoellner-Stiftung. The building was modernized exemplarily. It now has a bivalent heating system with a geothermal field. Modern measuring technology was implemented, and project findings of geothermal projects of the FITR were implemented.

  8. Geothermal reservoir categorization and stimulation study

    Energy Technology Data Exchange (ETDEWEB)

    Overton, H.L.; Hanold, R.J.

    1977-07-01

    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.

  9. Geologic model of the Cerro Prieto geothermal field

    Science.gov (United States)

    Halfman, S. E.; Howard, J. H.; Vonderhaar, S. P.

    1982-09-01

    One of the tasks under the Mexican-American cooperative agreement is the comprehensive geologic study of the Cerro Prieto geothermal field. Using logs from over seventy deep wells as the basic source of information on the subsurface geology, a working model of the Cerro Prieto geothermal field is developed.

  10. Structural investigations of Great Basin geothermal fields: Applications and implications

    Energy Technology Data Exchange (ETDEWEB)

    Faulds, James E [Nevada Bureau of Mines and Geology, Univ. of Nevada, Reno, NV (United States); Hinz, Nicholas H. [Nevada Bureau of Mines and Geology, Univ. of Nevada, Reno, NV (United States); Coolbaugh, Mark F [Great Basin Center for Geothermal Energy, Univ. of Nevada, Reno, NV (United States)

    2010-11-01

    Because fractures and faults are commonly the primary pathway for deeply circulating hydrothermal fluids, structural studies are critical to assessing geothermal systems and selecting drilling targets for geothermal wells. Important tools for structural analysis include detailed geologic mapping, kinematic analysis of faults, and estimations of stress orientations. Structural assessments are especially useful for evaluating geothermal fields in the Great Basin of the western USA, where regional extension and transtension combine with high heat flow to generate abundant geothermal activity in regions having little recent volcanic activity. The northwestern Great Basin is one of the most geothermally active areas in the USA. The prolific geothermal activity is probably due to enhanced dilation on N- to NNE-striking normal faults induced by a transfer of NW-directed dextral shear from the Walker Lane to NW-directed extension. Analysis of several geothermal fields suggests that most systems occupy discrete steps in normal fault zones or lie in belts of intersecting, overlapping, and/or terminating faults. Most fields are associated with steeply dipping faults and, in many cases, with Quaternary faults. The structural settings favoring geothermal activity are characterized by subvertical conduits of highly fractured rock along fault zones oriented approximately perpendicular to the WNW-trending least principal stress. Features indicative of these settings that may be helpful in guiding exploration for geothermal resources include major steps in normal faults, interbasinal highs, groups of relatively low discontinuous ridges, and lateral jogs or terminations of mountain ranges.

  11. Study of the structural control of fluid flow within the Cerro Prieto Geothermal Field, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Noble, J.E.; Manon, M.A.; Lippmann, M.J.; Witherspoon, P.A.

    1977-10-01

    The Lawrence Berkeley Laboratory and the Comision Federal de Electricidad of Mexico are conducting a joint investigation of the Cerro Prieto Geothermal Field, located approximately 35 km south of Mexicali, Baja California, Mexico, in the Sea of Cortez-Salton Trough. Recent analyses of various geophysical/electrical logs, temperature logs, production and geochemical data and the subsequently developed preliminary model of the structure of the geothermal system and the distribution of geothermal fluids are presented. Techniques routinely applied to petroleum exploration were successfully used in the development of a preliminary model of this water-dominated system. The study indicates the upwelling of geothermal fluids along an east bounding fault from a deep, as yet unexplored source. The fluids dissipate into various sand horizons at various depths. The resulting stratigraphic and fluid flow model is of importance in planning additional developments of the Cerro Prieto Geothermal Field.

  12. Seismic monitoring at the Geysers Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Romero, A.E. Jr.; Kirkpatrick, A.; Majer, E.L.; Peterson, J.E. Jr.

    1994-09-01

    This report summarizes the efforts of LBL to utilize MEQ data in reservoir definition as well as in evaluating its performance. Results of the study indicate that the velocity and attenuation variations correlate with the known geology of the field. At the NW Geysers, high velocity anomalies correspond to metagraywacke and greenstone units while low velocity anomalies seem to be associated with Franciscan melanges. Low Vp/Vs and high attenuation delineate the steam reservoir suggesting undersaturation of the reservoir rocks. Ongoing monitoring of Vp/Vs may be useful in tracking the expansion of the steam zone with time. Spatial and temporal patterns of seismicity exhibit compelling correlation with geothermal exploitation. Clusters of MEQs occur beneath active injection wells and appear to shift with changing injection activities. High resolution MEQ locations hold promise for inferring fluid flow paths, especially in tracking injectate. This study has demonstrated that continuous seismic monitoring may be useful as an active reservoir management tool.

  13. Geochemical exploration of the Chipilapa geothermal field, El Salvador

    Energy Technology Data Exchange (ETDEWEB)

    Nieva, David; Verma, Mahendra Pal; Santoyo, Edgar; Portugal, Enrique [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Campos, Alejandro [Comision Ejecutiva Hidroelectrica del Rio Lempa, Santa Tecla (El Salvador)

    1997-12-01

    Results of the geochemical exploration of the Ahuachapan-Chipilapa areas are presented. The procedure for interpreting the chemical composition of very dilute thermal waters is emphasised. Three groups of thermal waters are described, two with a geothermal brine component and one resulting from steam condensation. The model for one of the groups (Type 2) leads to predictions of temperature and chloride concentration that are reasonably close to those of the geothermal liquid feeding Chipilapa well CH-7B. In particular, it was predicted correctly that the salinities in the Chipilapa areas would be considerably lower than those in the Ahuachapan field. It is shown that the simultaneous modeling of the carbon dioxide concentration and isotopic composition of fumarole steam allows discrimination between primary and secondary steam. The composition of all fumarole samples is described as steam originating from a single reservoir fluid at 250degC, and composition {delta}{sup 18}O= - 4.1, {delta}D=-46, CO{sub 2}=5 x 10{sup -5} molar fraction. The total discharge composition of CH-7B confirms the trend observed in the Ahuachapan field of decreasing reservoir salinities towards the east. Postulating the existence of a deep reservoir brine in the eastern (Chipilapa) section of the system, with lower salinity but otherwise similar temperatures and isotopic composition to the Ahuachapan brine, allows for the generation of relatively simple models that explain the formation of the CH-7B brine, and the three groups of thermal waters. Type 1 waters are noteworthy in the sense that they result from a ternary mixture of meteoric water, geothermal brine and high-temperature steam condensate. The possibility that the east-west trend in salinity results from a process of dilution of brine with condensate from steam separated at very high temperatures is discussed. The distribution of the different types of hydrothermal manifestations delineates a lateral discharge system, with the

  14. Geothermal reservoir engineering, second workshop summaries, December 1-3, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, P.; Ramey, H.J. Jr.

    1976-12-01

    Workshop proceedings included the following: (1) During the Overview Session some papers, among others, discussed 'Geothermal Reservoir Engineering Research' and 'Geothermal Reservoir Engineering in Industry'; (2) Session I, Reservoir Physics, included papers on 'Steam Zone Temperature Gradients at the Geysers' and 'Water Influx in a Steam Producing Well'; (3) Session II, Well Testing, included papers on 'Borehole Geophysics in Geothermal Wells--Problems and Progress' and 'Herber-Pressure Interference Study'; (4) Session III, Field Development, included papers on 'A Reservoir Engineering Study of the East Mesa KGRA' and 'Determining the Optimal Rate of Geothermal Energy Extraction'; (5) Session IV, Well Stimulation, included papers on 'Fluid Flow Through a Large Vertical Crack in the Earth's Crust' and 'Explosive Stimulation of Geothermal Wells'; and (6) Session V, Modeling, included papers on 'Steam Transport in Porous Media' and 'Large-Scale Geothermal Field Parameters and Convection Theory.'

  15. Geothermal reservoir engineering, second workshop summaries, December 1-3, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, P.; Ramey, H.J. Jr.

    1976-12-01

    Workshop proceedings included the following: (1) During the Overview Session some papers, among others, discussed 'Geothermal Reservoir Engineering Research' and 'Geothermal Reservoir Engineering in Industry'; (2) Session I, Reservoir Physics, included papers on 'Steam Zone Temperature Gradients at the Geysers' and 'Water Influx in a Steam Producing Well'; (3) Session II, Well Testing, included papers on 'Borehole Geophysics in Geothermal Wells--Problems and Progress' and 'Herber-Pressure Interference Study'; (4) Session III, Field Development, included papers on 'A Reservoir Engineering Study of the East Mesa KGRA' and 'Determining the Optimal Rate of Geothermal Energy Extraction'; (5) Session IV, Well Stimulation, included papers on 'Fluid Flow Through a Large Vertical Crack in the Earth's Crust' and 'Explosive Stimulation of Geothermal Wells'; and (6) Session V, Modeling, included papers on 'Steam Transport in Porous Media' and 'Large-Scale Geothermal Field Parameters and Convection Theory.'

  16. The Geothermal Field Camp: Capacity building for geothermal energy systems in Indonesia

    Science.gov (United States)

    Moeck, I.; Sule, R.; Saptadji, N. M.; Deon, F.; Herdianita, N. R.; Jolie, E.; Suryantini, N.; Erbas, K.

    2012-04-01

    In July 2011, the first geothermal field camp was hold on Java/Indonesia near the city Bandung south of the volcanic field Tangkuban Perahu. The course was organized by the Institut Teknologie Bandung (ITB) and International Centre for Geothermal Research (ICGR) of the German Centre of Geosciences (GFZ). The purpose of the Geothermal Field Camp is to combine both field based work and laboratory analysis to ultimately better understand the data collected in field and to integrate data gained by various disciplines. The training belongs to a capacity building program for geothermal energy systems in Indonesia and initially aims to train the trainers. In a later stage, the educational personal trained by the Geothermal Field Camp shall be able to hold their individual Geothermal Field Camp. This is of special interest for Indonesia where the multitude of islands hindered a broad uniform education in geothermal energy systems. However, Indonesia hold the largest geothermal potential worldwide and educated personal is necessary to successfully develop this huge potential scattered over region in future. The interdisciplinary and integrative approach combined with field based and laboratory methodologies is the guiding principle of the Geothermal Field Camp. Tangkuban Perahu was selected because this field allows the integration of field based structural geological analysis, observation and sampling of geothermal manifestations as hot springs and sinters and ultimately of structural geology and surface geochemistry. This innovative training introduces in methods used in exploration geology to study both, fault and fracture systems and fluid chemistry to better understand the selective fluid flow along certain fractures and faults. Field geology covered the systematic measurement of faults and fractures, fault plane and fracture population analysis. In addition, field hydro-geochemistry focused on sampling techniques and field measurements onsite. Subsequent data analysis

  17. Geothermal Fields on the Volcanic Axis of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Mercado, S.; Gonzalez, A.

    1980-12-16

    At present in Mexico, geothermal energy is receiving a great impulse due to the excellent results obtained in the Cerro Prieto geothermal field, in which a geothermoelectric plant is operated. This plant has four units of 37.5 MW each, with a total capacity of 150 MW, and under program 470 MW more by 1984. The Government Institution, Comisi6n Federal de Electricidad, is in charge of the exploration and exploitation of geothermal fields as well as construction and operation of power plants in Mexico. By this time CFE has an extensive program of exploration in the central part of Mexico, in the Eje Neovolcdnico. In this area, several fields with hydrothermal alteration are under exploration, like the Michoac6n geothermal area, where Los Azufres geothermal field is being developed. Seventeen wells have been drilled and twelve of them presented excellent results, including two dry steam wells. In other areas, such as Arar6, Cuitzeo, San Agustln del Maiz,Ixtldn de Los Hervores and Los Negritos, geological, geophysical and geochemical explorations have been accomplished, including shallow well drilling with good results. Another main geothermal area is in the State of Jalisco with an extension of 5,000 m2, where La Primavera geothermal field shows a lot of volcanic domes and has an intensive hydrothermal activity. Deep wells have been drilled, one of them with a bottom temperature of 29OOC. Other fields in this area, like San Narcos, Hervores de La Vega, La Soledad, Villa Corona, etc., have a good geothermal potential. A new geothermal area has been explored recently in the eastern part of the country named Los Humeros, Puebla. In this area studies are being made and there are plans for well drilling exploration by the beginning of 1981. Like this one, there are many other areas in the country in which 300 hydrothermal alteration zones are been classified and 100 of them are considered economically exploitable.

  18. Symposium in the field of geothermal energy

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, Miguel; Mock, John E.

    1989-04-01

    Mexico and the US are nations with abundant sources of geothermal energy, and both countries have progressed rapidly in developing their more accessible resources. For example, Mexico has developed over 600 MWe at Cerro Prieto, while US developers have brought in over 2000 MWe at the Geysers. These successes, however, are only a prologue to an exciting future. All forms of energy face technical and economic barriers that must be overcome if the resources are to play a significant role in satisfying national energy needs. Geothermal energy--except for the very highest grade resources--face a number of barriers, which must be surmounted through research and development. Sharing a common interest in solving the problems that impede the rapid utilization of geothermal energy, Mexico and the US agreed to exchange information and participate in joint research. An excellent example of this close and continuing collaboration is the geothermal research program conducted under the auspices of the 3-year agreement signed on April 7, 1986 by the US DOE and the Mexican Comision Federal de Electricidad (CFE). The major objectives of this bilateral agreement are: (1) to achieve a thorough understanding of the nature of geothermal reservoirs in sedimentary and fractured igneous rocks; (2) to investigate how the geothermal resources of both nations can best be explored and utilized; and (3) to exchange information on geothermal topics of mutual interest.

  19. Sperry Low Temperature Geothermal Conversion System, Phase I and Phase II. Volume IV. Field activities. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, C.

    1984-01-01

    This volume describes those activities which took place at the Sperry DOE Gravity Head plant site at the East Mesa Geothermal Reservoir near Holtville, California between February 1980, when site preparation was begun, and November 1982, when production well 87-6 was permanently abandoned. Construction activities were terminated in July 1981 following the liner collapse in well 87-6. Large amounts of program time manpower, materials, and funds had been diverted in a nine-month struggle to salvage the production well. Once these efforts proved futile, there was no rationale for continuing with the site work unless and until sufficient funding to duplicate well 87-6 was obtained. Activities reported here include: plant construction and pre-operational calibration and testing, drilling and completion of well 87-6, final repair effort on well 87-6, abandonment of well 87-6, and performance evaluation of well 87.6. (MHR)

  20. Geothermal System at 21{degrees}N, East Pacific Rise: Physical Limits on Geothermal Fluid and Role of Adiabatic Expansion.

    Science.gov (United States)

    Bischoff, J L

    1980-03-28

    Pressure-volume-temperature relations for water at the depth of the magma chamber at 21 degrees N on the East Pacific Rise suggest that the maximum subsurface temperature of the geothermal fluid is about 420 degrees C. Both the chemistry of the discharging fluid and thermal balance considerations indicate that the effective water/rock ratios in the geothermal system are between 7 and 16. Such low ratios preclude effective metal transport at temperatures below 350 degrees C, but metal solubilization at 400 degrees C and above is effective even at such low ratios. It is proposed that the 420 degrees C fluid ascends essentially adiabatically and in the process expands, cools, and precipitates metal sulfides within the upper few hundred meters of the sea floor and on the sea floor itself.

  1. Characterization of deep ground geothermal field in Jiahe Coal Mine

    Institute of Scientific and Technical Information of China (English)

    Zhang Yi; Guo Dongming; He Manchao; Jiang Yaodong; Yang Qing

    2011-01-01

    Research into the characteristics of geothermal fields is important for the control of heat damage in mines.Based on measured geothermal data of boreholes from -200 m to -1200 m in a Jiahe Coal Mine,we demonstrate non-linear but increasing relations of both geo-temperatures and geothermal gradients with increases depth.Numerically,we fitted the relationship between geo-temperatures and depth,a first-order exponential decay curve,formulated as:T(h) - -4.975 + 23.08 × exp(-h/1736.1 ).

  2. Geothermal reservoir at Tatapani Geothermal field, Surguja district, Madhya Pradesh, IN

    Energy Technology Data Exchange (ETDEWEB)

    Pitale, U.L.; Sarolkar, P.B.; Rawat, H.S.; Shukia, S.N.

    1996-01-24

    The Tatapani Geothermal field, located on the Son-Narmada mega lineament is one of the most intense geothermal manifestation, with hot spring temperature of 98°c. in Central India. 21 Exploratory and thermal gradient boreholes followed by 5 production wells for proposed 300 KWe binary cycle power plant, have revealed specific reservoir parameters of shallow geothermal reservoir of 110°c in upper 350 m of geothermal system and their possible continuation to deeper reservoir of anticipated temperature of 160 ± 10°c. Testing of five production wells done by Oil and Natural Gas Corporation concurrently with drilling at different depths and also on completion of drilling, have established feeder zones of thermal water at depth of 175-200 m, 280-300 m, maximum temperature of 112.5°c and bottom hole pressure of 42 kg/cm². Further interpretation of temperature and pressure profiles, injection test, well head discharges and chemical analysis data has revealed thermal characteristics of individual production wells and overall configuration of .thermal production zones with their permeability, temperature, and discharge characteristics in the shallow thermal reservoir area. Well testing data and interpretation of reservoir parameters therefrom, for upper 350 m part of geothermal system and possible model of deeper geothermal reservoir at Tatapani have been presented in the paper.

  3. Investigations of deep resistivity structures at the Wairakei geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Bibby, Hugh M.; Risk, George F.; Grant Caldwell, T.; Heise, Wiebke [GNS Science, P.O. Box 30368, Lower Hutt (New Zealand)

    2009-03-15

    The Wairakei geothermal field was the proving ground for the use of electrical resistivity methods for geothermal exploration. At this site it was first demonstrated that a large contrast in resistivity existed between geothermal ground and the cold surroundings. Within the top 500 m of the geothermal field, low-resistivity (5-10 {omega}m) reflects the effects of both the hot saline water in the pore spaces and the conductive rock-matrix. The first surveys at Wairakei used a Wenner array (a {proportional_to}550 m) to measure the resistivity values along tracks throughout the field; contour maps of the resistivities were used to estimate the lateral extent of the geothermal waters at a few hundred metres depth. In the late 1960s the Wenner array was superseded by the Schlumberger array (AB/2 = 500 m and 1000 m), which enabled deeper penetration and better definition of the extent of the geothermal waters. These early surveys showed that the bounds of the geothermal waters were often sharp, leading to the concept that a 'resistivity boundary' could be defined for New Zealand's liquid-dominated geothermal fields. As new methods of measuring electrical structure with greater precision became available, Wairakei was often chosen as the testing ground. In 1982, a deep penetrating tensor bipole-dipole survey was made over the northern part of the field to provide close-spaced data across the boundary, leading to a better definition of the boundary and its change with depth. A similar survey over the eastern edge of the field revealed a very sharp boundary with an apparent correlation between its location and a deeper caldera structure. The first application of tensor time-domain resistivity (tensor LOTEM) was made across the north-western edge of Wairakei in 1997 giving both a detailed image of the boundary and showing that it was possible to trace geological structures within the geothermal field. The most commonly used method for resistivity surveying in

  4. Extremely Shallow Extensional Faulting Near Geothermal Fields

    Science.gov (United States)

    Hudnut, K. W.; Wei, S.; Donnellan, A.; Fielding, E. J.; Graves, R. W.; Helmberger, D. V.; Liu, Z.; Parker, J. W.; Treiman, J. A.

    2013-12-01

    side down slip. Up to 18 cm/s ground motion were observed at four seismic stations within 10 km which are modeled by northward rupture directivity with rupture speed of ~1.0-1.5 km/s. Although most energy in Brawley Seismic Zone swarms is released in deeper and larger strike-slip events, we observe surprisingly that the recent cases of surface faulting in 2005 on the Kalin fault (Rymer et al., USGS OFR 2010-1333) and 2012 preferentially involve normal fault surface slip in close proximity to geothermal fields, as did the 2006 Morelia fault case (Suárez-Vidal et al., SRL 2007). The Aug. 2012 case was the latest of three minor extensional surface ruptures, each associated with moderate seismic activity near geothermal fields. We compare this latest case, with its ~3.5 km surface break, and the two earlier examples with ~0.5 km (2005) and ~2.0 km (2006) long surface breaks with similar NE-SW to NNE-SSW orientations. All three cases had tectonic surface slip of greater than 15 cm but less than 30 cm, involved mostly normal fault slip, and occurred within extensional step-over zones between the San Andreas and Imperial faults (2005 & 2012), and between the Imperial and Cerro Prieto faults (2006).

  5. Geochemistry of igneous rocks from the Cerro Prieto geothermal field, northern Baja California, Mexico

    Science.gov (United States)

    Herzig, C. T.

    1990-08-01

    Fractional crystallization of basaltic magma, derived from an oceanic affinity source region present beneath the Salton Trough and emplaced into a pull-apart basin of this continental rift regime, produced a tholeiitic suite of hypabyssal rocks consisting of basalt, andesite and dacite within the Cerro Prieto geothermal field, located in northern Baja California, Mexico. Higher light-rare-earth-element abundances for a basalt from the Cerro Prieto geothermal field in comparison to basalts from the Gulf of California and the East Pacific Rise suggest partial assimilation of crustal materials into the parental magmas generated beneath the Salton Trough. The crustal contaminant may be present near the surface today in the form of granitoids of the Peninsular Ranges batholith, at deeper levels as hydrothermally altered materials near the base of the Salton Trough, or may be a relict feature of Tertiary subduction contained within the upper mantle beneath the Salton Trough. The Sr isotopic compositions of dacites from the nearby Cerro Prieto volcano range from 0.7029 to 0.7036, indicating an oceanic affinity source for these rocks. The suite of hypabyssal rocks of tholeiitic affinity present within the Cerro Prieto geothermal field, related by fractional crystallization, link the dacite volcano of Cerro Prieto to gabbroic plutons inferred to exist beneath the Cerro Prieto geothermal field.

  6. Stress, faulting and fluid flow in the Coso Geothermal Field, CA

    Science.gov (United States)

    Davatzes, N. C.; Hickman, S.

    2006-12-01

    We integrate new geologic mapping and new in situ measurements of stress orientations and magnitudes from studies of wells within and on the flanks of the geothermal system with existing data sets to refine a geomechanical model for the Coso geothermal field. Stress orientations (averaged from several hundred to thousand meters of vertical borehole data) in wells across the field are fairly uniform and are consistent with focal mechanism inversions of earthquake clusters for stress and incremental strain. Active faults trending NNW-SSE to NNE-SSW are well oriented for normal slip in the current stress field, where the mean least principal horizontal compressive stress, Shmin, orientation is 108° ± 24º in a transitional strike-slip to normal faulting stress regime. These structures bound regions of intense micro-seismicity and are complexly associated with surface hydrothermal activity. WNW-ESE trending faults are also associated with distinct regions of enhanced seismicity but are only associated with surface hydrothermal activity where they intersect more northerly trending normal faults. These faults show no evidence for Quaternary slip at the surface and are poorly oriented in the modern stress field. These results together with stress magnitudes measured in the East Flank of the field suggest that the most productive portions of the Coso geothermal field are in high deviatoric stress environments conducive to normal faulting. Recent earthquake relocations and incremental strain inversions map areas of extensional strain located over the southern part of the Main Field and reaching east and north into the East Flank consistent with our borehole analyses. The resulting relatively low mean stress is conducive to dilation and increased permeability accompanying fault slip and coincides with the hottest areas in the geothermal field. Similar regions of locally reduced mean stress might arise from mechanical interaction during slip on intersecting fault segments

  7. Matched Field Detection of Microseismicity in a Geothermal Field

    Science.gov (United States)

    Templeton, D. C.; Harris, D. B.

    2010-12-01

    The delineation of fractures in geothermal fields is an important aspect of reservoir management that often is attempted by mapping the distribution of microseismicity. Traditional methods of earthquake location frequently used for this purpose are labor-intensive, requiring phase-arrival picking and high-resolution location with a relative location routine such as hypoDD. Automatic picks often require assessment and correction by an analyst. Frequently, event superposition and poor signal-to-noise ratio limit the number of usable events to one-third or fewer of the detectable transients. In some applications smaller events may become so numerous that they come to resemble a continuous random process that is not amenable to location analysis suited to transient arrivals. We are exploring the application of matched field processing (MFP) to map emissions from a geothermal field. MFP is a technique developed in underwater sound to localize emissions from continuous sources such as submersibles. The technique resembles beamforming or FK analysis in that it focuses the wavefield emanating from a particular source location by matching, in the frequency domain, the phase and amplitude of waves incident across the observing aperture. It differs from beamforming and FK methods in that the phase and amplitude structure is not determined by a plane-wave model. Wavefield structure may be determined empirically, by measuring it from observations of reference events, or it may be developed by full-waveform synthetics computed through a velocity model of the medium. In this presentation, we explore the empirical approach. Our objective is to map all of the observable seismicity in a geothermal field, not just the larger events that are sufficiently distinct to permit accurate picks. Our approach would extend current techniques, using the larger events conventionally located as master events to define wavefield templates for mapping normally-discarded indistinct seismicity. Since

  8. Direct application of east coast geothermal resources in a frozen food plant. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ammerlaan, A.C.F.; Knebel, M.E.; Czarnecki, R.J.

    1979-01-01

    The technical and economic viability of retrofitting an existing frozen food plant in Salisbury, Maryland to utilize the anticipated geothermal resources in that area was evaluated, via a budgetary level design and cost estimating analysis. Based on predicted reservoir data, a design concept was developed from production well through the plant to final brine disposal. A parametric analysis of capital and operating costs was performed which covered the range of geothermal design data developed. Relevant social, financial, environmental, legal, and regulatory institutional relationships were examined and ways to eliminate any barriers they presented against the proposed application were explored. Based on results from the other tasks, the existing DOE East Coast Geothermal Development Plan was evaluated and possible alterations were proposed. (MHR)

  9. Is radon a potential risk in geothermal fields?

    Energy Technology Data Exchange (ETDEWEB)

    Balcazar, M.; Tavera, L.; Lopez, A. [Instituto Nacional de Investigaciones Nucleares, Mexico City (Mexico)

    1998-12-31

    Some environmental groups in Mexico have shown concern, by the fact that natural radon emanation in geothermal fields could be considered as a potential risk for human health. As part of the studies recommended by the Ministry of Energy and to provide technical answers to the request of environmental groups, a study of the radon emanation and its impact to human health was carried out at the Primavera Mexican geothermal energy field under prospecting. It was found that radon concentration decreases with temperature of geothermal fluids and increases with the enthalpy of the well. In any case, using the appropriate corrections, radon values were similar to those of ground water. Radon values in the atmosphere of the field show no potential risk for human health. (author)

  10. Drilling fluid/formation interaction at simulated in situ geothermal conditions. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Enniss, D.O.; Bergosh, J.L.; Butters, S.W.; Jones, A.H.

    1980-07-01

    Interaction of drilling fluids with a geothermal reservoir formation can result in significant permeability impairment and therefore reduced well productivity. This interaction is studied under simulated in situ geothermal conditions of overburden stress, pore fluid pressure, temperature, and pore fluid chemistry. Permeability impairment of an East Mesa KGRA reservoir material is evaluated as a function of stagnation time, drilling fluid, and temperature. Results indicate that all of these parameters contribute significantly to the magnitude and the reversibility of the impairment.

  11. 3D Magnetotelluic characterization of the Coso GeothermalField

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Gregory A.; Hoversten, G. Michael; Wannamaker, Philip E.; Gasperikova, Erika

    2007-04-23

    Electrical resistivity may contribute to progress inunderstanding geothermal systems by imaging the geometry, bounds andcontrolling structures in existing production, and thereby perhapssuggesting new areas for field expansion. To these ends, a dense grid ofmagnetotelluric (MT) stations plus a single line of contiguous bipolearray profiling has been acquired over the east flank of the Cosogeothermal system. Acquiring good quality MT data in producing geothermalsystems is a challenge due to production related electromagnetic (EM)noise and, in the case of Coso, due to proximity of a regional DCintertie power transmission line. To achieve good results, a remotereference completely outside the influence of the dominant source of EMnoise must be established. Experimental results so far indicate thatemplacing a reference site in Amargosa Valley, NV, 65 miles from the DCintertie, isstill insufficient for noise cancellation much of the time.Even though the DC line EM fields are planar at this distance, theyremain coherent with the nonplanar fields in the Coso area hence remotereferencing produces incorrect responses. We have successfully unwrappedand applied MT times series from the permanent observatory at Parkfield,CA, and these appear adequate to suppress the interference of thecultural EM noise. The efficacy of this observatory is confirmed bycomparison to stations taken using an ultra-distant reference site eastof Socorro, NM. Operation of the latter reference was successful by usingfast ftp internet communication between Coso Junction and the New MexicoInstitute of Mining and Technology, using the University of Utah site asintermediary, and allowed referencing within a few hours of datadownloading at Coso. A grid of 102 MT stations was acquired over the Cosogeothermal area in 2003 and an additional 23 stations were acquired toaugment coverage in the southern flank of the first survey area in 2005.These data have been inverted to a fully three

  12. A Galerkin, finite-element analysis of steady-state flow and heat transport in the shallow hydrothermal system in the East Mesa area, Imperial Valley, California

    Science.gov (United States)

    Miller, R.E.

    1977-01-01

    A steady-state simulation model was applied to the shallow hydrothermal system in the East Mesa area of Imperial Valley, Calif. The steady-state equations of flow and heat transport were solved by use of a Galerkin, finite-element method. A solution was obtained by iterating between the temperature and pressure equations, using updated densities and viscosities. Temperature and pressure were obtained for each node, and corresponding head values were calculated. The simulated temperature and pressure patterns correlated well with the observed patterns. Additional data, mainly from test drilling, would be required for construction of a similar model of the deep hydrothermal system.

  13. Field Plot Points for Mesa Verde National Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The Mesa Verde National Park Classification Releve Location zip shapefile (meveplot.zip) was developed as a Geographic Information Systems (GIS) product to represent...

  14. Some comments on the La Primavera geothermal field, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez A, B.; Lippmann, M.J.

    1983-12-01

    The La Primavera geothermal field is located about 20 km west of the city of Guadalajara, Jalisco, in the western part of the Mexican Neovolcanic Axis. Initial results of five deep exploration wells (down to 2000 m depth) were very promising; measured downhole temperatures exceed 300/sup 0/C. During production, however, downhole temperatures dropped, and the chemistry of the fluids changed. The analysis of geologic, mineralogic, geochemical, and well completion data indicate that colder fluids flow down the wellbore from shallower aquifers cooling the upper zones of the geothermal reservoir. This problem is attributed to inadequate well completions. Doubts have arisen about continuing the exploration of the field because of the somewhat disappointing drilling results. However, a more thorough analysis of all available data indicates that a good geothermal prospect might exist below 3000 m, and that it could be successfully developed with appropriately located and completed wells.

  15. Groundwater contamination mechanism in a geothermal field: a case study of Balcova, Turkey.

    Science.gov (United States)

    Aksoy, Niyazi; Simşek, Celalettin; Gunduz, Orhan

    2009-01-01

    The Balcova Geothermal Field (BGF) located in Izmir, Turkey is situated on an east-west directed graben plain within which the hot waters surface from a fault zone that cuts the Mesozoic aged Bornova Flysch. Due to the low permeability and porosity of the Bornova Flysch, the geothermal water cycles along the immediate vicinity of the Agamemnon fault and mixes with cold waters at different depths of this fractured zone. Within the scope of this study, the mixing patterns and the groundwater contamination mechanisms are analyzed by, hydrogeological and hydrogeochemical methods. Based on the results of this research, it has been found out that the hot geothermal water and the cold regional groundwater resources of the surficial aquifer mix within the fractured zone in Bornova Flysch and within the Quaternary alluvium aquifer due to natural and anthropogenic activities including (i) the natural upward movement of geothermal fluid along the fault line, (ii) the accelerated upward seepage of geothermal fluid from faulty constructed boreholes drilled in the area, (iii) the faulty reinjection applications; and, (iv) the uncontrolled discharge of waste geothermal fluid to the natural drainage network. As a result of these activities, the cold groundwater reserves of the alluvial aquifer are contaminated thermally and chemically in such a way that various toxic chemicals including arsenic, antimony and boron are introduced to the heavily used surficial aquifer waters hindering their use for human consumption and agricultural irrigation. Furthermore, the excessive pumping from the surficial aquifer as well as the reduced surface water inflow into BGF due to the dam constructed on Ilica Creek intensify the detrimental effects of this contamination. Based on the results of this study, it can be concluded that the groundwater pollution in BGF will expand and reach to the levels of no return unless a series of preventive measures is taken immediately.

  16. Groundwater contamination mechanism in a geothermal field: A case study of Balcova, Turkey

    Science.gov (United States)

    Aksoy, Niyazi; Şimşek, Celalettin; Gunduz, Orhan

    2009-01-01

    The Balcova Geothermal Field (BGF) located in Izmir, Turkey is situated on an east-west directed graben plain within which the hot waters surface from a fault zone that cuts the Mesozoic aged Bornova Flysch. Due to the low permeability and porosity of the Bornova Flysch, the geothermal water cycles along the immediate vicinity of the Agamemnon fault and mixes with cold waters at different depths of this fractured zone. Within the scope of this study, the mixing patterns and the groundwater contamination mechanisms are analyzed by, hydrogeological and hydrogeochemical methods. Based on the results of this research, it has been found out that the hot geothermal water and the cold regional groundwater resources of the surficial aquifer mix within the fractured zone in Bornova Flysch and within the Quaternary alluvium aquifer due to natural and anthropogenic activities including (i) the natural upward movement of geothermal fluid along the fault line, (ii) the accelerated upward seepage of geothermal fluid from faulty constructed boreholes drilled in the area, (iii) the faulty reinjection applications; and, (iv) the uncontrolled discharge of waste geothermal fluid to the natural drainage network. As a result of these activities, the cold groundwater reserves of the alluvial aquifer are contaminated thermally and chemically in such a way that various toxic chemicals including arsenic, antimony and boron are introduced to the heavily used surficial aquifer waters hindering their use for human consumption and agricultural irrigation. Furthermore, the excessive pumping from the surficial aquifer as well as the reduced surface water inflow into BGF due to the dam constructed on Ilica Creek intensify the detrimental effects of this contamination. Based on the results of this study, it can be concluded that the groundwater pollution in BGF will expand and reach to the levels of no return unless a series of preventive measures is taken immediately.

  17. Measurement of Subsidence in the Yangbajain Geothermal Fields from TerraSAR-X

    Science.gov (United States)

    Li, Yongsheng; Zhang, Jingfa; Li, Zhenhong

    2016-08-01

    Yangbajain contains the largest geothermal energy power station in China. Geothermal explorations in Yangbajain first started in 1976, and two plants were subsequently built in 1981 and 1986. A large amount of geothermal fluids have been extracted since then, leading to considerable surface subsidence around the geothermal fields. In this paper, InSAR time series analysis is applied to map the subsidence of the Yangbajain geothermal fields during the period from December 2011 to November 2012 using 16 senses of TerraSAR-X stripmap SAR images. Due to its high resolution and short repeat cycle, TerraSAR-X provides detailed surface deformation information at the Yangbajain geothermal fields.

  18. Radon studies for extending Los Azufres geothermal energy field in Mexico

    CERN Document Server

    Tavera, L; Camacho, M E; Chavez, A; Pérez, H; Gómez, J

    1999-01-01

    Los Azufres is a 98 MW producing geothermal energy field situated in the Mexican volcanic belt at the west part of the country. Recently, hydrothermal activity and geochemical analysis of geothermal fluids from the north part of the geothermal field gave indications of a possible geothermal-production area, similar to the already producing field. In order to investigate the activity of geological structures, which are considered the means of geothermal fluids transporters, radon mapping was carried out using sets of 240 LR-115 detectors in the area of interest. Radon values higher than 10 kBq m sup - sup 3 were considered anomalous and indicative of geothermal anomalies.

  19. Human Resources in Geothermal Development

    Energy Technology Data Exchange (ETDEWEB)

    Fridleifsson, I.B.

    1995-01-01

    Some 80 countries are potentially interested in geothermal energy development, and about 50 have quantifiable geothermal utilization at present. Electricity is produced from geothermal in 21 countries (total 38 TWh/a) and direct application is recorded in 35 countries (34 TWh/a). Geothermal electricity production is equally common in industrialized and developing countries, but plays a more important role in the developing countries. Apart from China, direct use is mainly in the industrialized countries and Central and East Europe. There is a surplus of trained geothermal manpower in many industrialized countries. Most of the developing countries as well as Central and East Europe countries still lack trained manpower. The Philippines (PNOC) have demonstrated how a nation can build up a strong geothermal workforce in an exemplary way. Data from Iceland shows how the geothermal manpower needs of a country gradually change from the exploration and field development to monitoring and operations.

  20. Deep geothermal processes acting on faults and solid tides in coastal Xinzhou geothermal field, Guangdong, China

    Science.gov (United States)

    Lu, Guoping; Wang, Xiao; Li, Fusi; Xu, Fangyiming; Wang, Yanxin; Qi, Shihua; Yuen, David

    2017-03-01

    This paper investigated the deep fault thermal flow processes in the Xinzhou geothermal field in the Yangjiang region of Guangdong Province. Deep faults channel geothermal energy to the shallow ground, which makes it difficult to study due to the hidden nature. We conducted numerical experiments in order to investigate the physical states of the geothermal water inside the fault zone. We view the deep fault as a fast flow path for the thermal water from the deep crust driven up by the buoyancy. Temperature measurements at the springs or wells constrain the upper boundary, and the temperature inferred from the Currie temperature interface bounds the bottom. The deepened boundary allows the thermal reservoir to revolve rather than to be at a fixed temperature. The results detail the concept of a thermal reservoir in terms of its formation and heat distribution. The concept also reconciles the discrepancy in reservoir temperatures predicted from both quartz and Na-K-Mg. The downward displacement of the crust increases the pressure at the deep ground and leads to an elevated temperature and a lighter water density. Ultimately, our results are a first step in implementing numerical studies of deep faults through geothermal water flows; future works need to extend to cases of supercritical states. This approach is applicable to general deep-fault thermal flows and dissipation paths for the seismic energy from the deep crust.

  1. Dramatic incidents during drilling at Wairakei Geothermal Field, New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, Richard S. [11 Fiesta Grove, Raumati Beach, Paraparaumu (New Zealand); Hunt, Trevor M. [GNS Science, Wairakei Research Centre, Private Bag 2000, Taupo (New Zealand); King, Tom R. [Tom King Ltd, Taupo (New Zealand); Thompson, Geoffrey E.K. [Geophysics Division, DSIR, Wairakei (New Zealand)

    2009-03-15

    The paper describes three blowouts associated with Wairakei wells that had been drilled during the late 1950s to early 1960s, near areas of surface thermal manifestations. Also discussed are the 1960s drilling practices in this geothermal field, the remedial actions undertaken to regain well control, and the lessons learned from these unexpected incidents. (author)

  2. Geophysical monitoring at the Cerro Prieto geothermal field

    Science.gov (United States)

    Wilt, M.; Zelwer, R.; Majer, E. L.

    1982-09-01

    A program of reservoir monitoring at the Cerro Prieto geothermal field using surface geophysical methods with the objective of observing changes resulting from production is described. The three methods used, dipole-dipole resistivity, precision gravity, and passive seismic monitoring, are discussed.

  3. Temperature distribution in the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Castillo B, F.; Bermejo M, F.J.; Domiguez A, B.; Esquer P, C.A.; Navarro O, F.J.

    1981-01-01

    A series of temperature and pressure logs and flow rate measurements was compiled for each of the geothermal wells drilled to different reservoir depths between October 1979 and December 1980. Based on the valuable information obtained, a series of graphs showing the thermal characteristics of the reservoir were prepared. These graphs clearly show the temperature distribution resulting from the movement of fluids from the deep regions toward the higher zones of the reservoir, thus establishing more reliable parameters for locating new wells with better production zones. Updated information based on data from new deep wells drilled in the geothermal field is presented here. This new information does not differ much from earlier estimates and theories. However, the influence of faulting and fracturing on the hydrothermal recharge of the geothermal reservoir is seen more clearly.

  4. Geothermal Field Near Rotorua, New Zealand

    Science.gov (United States)

    2002-01-01

    Historical sketches show the indigenous Maori cooking with natural hot waters and steam prior to the arrival of Europeans on North Island, New Zealand. Since the 1950s, geothermal heat and steam have been exploited for both heating and electrical power generation, and some excess electrical power is exported to South Island. The geothermal development can be identified by the unique patterns of infrastructure that look like tan beads on a string in the midst of otherwise green vegetation. This one near the town of Rotorua lies within a northeast-trending line of active volcanoes (Ruapehu, Tongariro, and White Island) that are the surface result of the Pacific tectonic plate descending beneath the Australian-Indian plate. Image STS110-726-10 was taken by space shuttle crewmembers in April 2002 using a Hasselblad film camera. Image provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  5. Seismic Activity at tres Virgenes Volcanic and Geothermal Field

    Science.gov (United States)

    Antayhua, Y. T.; Lermo, J.; Quintanar, L.; Campos-Enriquez, J. O.

    2013-05-01

    The volcanic and geothermal field Tres Virgenes is in the NE portion of Baja California Sur State, Mexico, between -112°20'and -112°40' longitudes, and 27°25' to 27°36' latitudes. Since 2003 Power Federal Commission and the Engineering Institute of the National Autonomous University of Mexico (UNAM) initiated a seismic monitoring program. The seismograph network installed inside and around the geothermal field consisted, at the beginning, of Kinemetrics K2 accelerometers; since 2009 the network is composed by Guralp CMG-6TD broadband seismometers. The seismic data used in this study covered the period from September 2003 - November 2011. We relocated 118 earthquakes with epicenter in the zone of study recorded in most of the seismic stations. The events analysed have shallow depths (≤10 km), coda Magnitude Mc≤2.4, with epicentral and hypocentral location errors geothermal explotation zone where there is a system NW-SE, N-S and W-E of extensional faults. Also we obtained focal mechanisms for 38 events using the Focmec, Hash, and FPFIT methods. The results show normal mechanisms which correlate with La Virgen, El Azufre, El Cimarron and Bonfil fault systems, whereas inverse and strike-slip solutions correlate with Las Viboras fault. Additionally, the Qc value was obtained for 118 events. This value was calculated using the Single Back Scattering model, taking the coda-waves train with window lengths of 5 sec. Seismograms were filtered at 4 frequency bands centered at 2, 4, 8 and 16 Hz respectively. The estimates of Qc vary from 62 at 2 Hz, up to 220 at 16 Hz. The frequency-Qc relationship obtained is Qc=40±2f(0.62±0.02), representing the average attenuation characteristics of seismic waves at Tres Virgenes volcanic and geothermal field. This value correlated with those observed at other geothermal and volcanic fields.

  6. Volume strain within the Geysers geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Mossop, Antony [Department of Geophysics, Stanford University, Stanford, California (United States); Segall, Paul [Department of Geophysics, Stanford University, Stanford, California (United States)

    1999-12-10

    During the 1970s and 1980s. The Geysers geothermal region was rapidly developed as a site of geothermal power production. The likelihood that this could cause significant strain within the reservoir, with corresponding surface displacements, led to a series of deformation monitoring surveys. In 1973, 1975, 1977, and 1980, The Geysers region was surveyed using first-order, class I, spirit leveling. In 1994, 1995, and 1996, many of the leveling control monuments were resurveyed using high-precision Global Positioning System receivers. The two survey methods are reconciled using the GEOID96 geoid model. The displacements are inverted to determine volume strain within the reservoir. For the period 1980-1994, peak volume strains in excess of 5x10{sup -4} are imaged. There is an excellent correlation between the observed changes in reservoir steam pressures and the imaged volume strain. If reservoir pressure changes are inducing volume strain, then the reservoir quasi-static bulk modulus K must be <4.6x10{sup 9} Pa. However, seismic velocities indicate a much stiffer reservoir with K=3.4x10{sup 10} Pa. This apparent discrepancy is shown to be consistent with predicted frequency dependence in K for fractured and water-saturated rock. Inversion of surface deformation data therefore appears to be a powerful method for imaging pressure change within the body of the reservoir. Correlation between induced seismicity at The Geysers and volume strain is observed. However, earthquake distribution does not appear to have a simple relationship with volume strain rate. (c) 1999 American Geophysical Union.

  7. INTERGEO - Central/East European Collaboration Network on direct application of geothermal energy

    Energy Technology Data Exchange (ETDEWEB)

    Popovski, K. [Central/East European Collaboration Network on Direct Application of Geothermal Energy, Bitola (Yugoslavia); Arpasi, M. [International Geothermal Association - European Branch, Budapest (Hungary)

    1997-12-01

    A proposal for organisation of a Network to be known as INTERGEO is presented, which should extend and reinforce the cooperation for the development of the direct application of geothermal energy between the developed EC countries and the ones of the so called Central/East European region. Unter the term `developed countries` for this particular energy source utilisation mainly Italy, France and Germany should be understood. The Central/East European region consists the following countries: Albania, Bosnia and Herzegovina, Bulgaria, Belarus, Croatia, Czech Republic, Estonia, Hungary, Latvia, Lituania, Macedonia, Moldova, Poland, Roumania, Slovenia, Slovakia, Turkey, Ukraine and Yugoslavia. The idea itself, the need and possibilities for organisation, possible plan of action and expected benefits for the EC and Central/East European countries are elaborated in order to come to the conclusions for the proposal justifiableness and feasibility for realisation. (orig.)

  8. A Reservoir Assessment of the Geysers Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Richard P.; Chapman, Rodger H.; Dykstra, Herman; Stockton, A.D.

    1981-01-01

    Big Sulphur Creek fault zone, in The Geysers Geothermal field, may be part of a deep-seated, wrench-style fault system. Hydrothermal fluid reservoir may rise through conduits beneath the five main anomalies associated with the Big Sulphur Creek wrench trend. Upon moderately dipping, fracture network. Condensed steam at the steep reservoir flank drains back to the hot water table. These flanks are defined roughly by marginally-producing geothermal wells. Field extensions are expected to be on the southeast and northwest. Some geophysical anomalies (electrical resistivity and audio-magnetotelluric) evidently are caused by the hot water geothermal field or zones of altered rocks; others (gravity, P-wave delays, and possibly electrical resistivity) probably represent the underlying heat source, a possible magma chamber; and others (microearthquake activity) may be related to the steam reservoir. A large negative gravity anomaly and a few low-resitivity anomalies suggest areas generally favorable for the presence of steam zones, but these anomalies apparently do not directly indicate the known steam reservoir. Monitoring gravity and geodetic changes with time and mapping microearthquake activity are methods that show promise for determining reservoir size, possible recharge, production lifetime, and other characteristics of the known stream field. Seismic reflection data may contribute to the efficient exploitation of the field by identifying fracture zones that serve as conduits for the steam. (DJE-2005)

  9. Site-specific analysis of hybrid geothermal/fossil power plants

    Energy Technology Data Exchange (ETDEWEB)

    1977-06-01

    A preliminary economic analysis of a hybrid geothermal/coal power plant has been completed for four geothermal Resource areas: Roosevelt Hot Springs, Coso Hot Springs, East Mesa and Long Valley. A hybrid plant would be economically viable at Roosevelt Hot Springs and somewhat less so at Coso Hot Springs. East Mesa and Long Valley show no economic promise. A well-designed hybrid plant could use geothermal energy for boiler feedwater heating, auxiliary power, auxiliary heating, and cooling water. Construction and operation of a hybrid plant at either Roosevelt Hot Springs or Coso Hot Springs is recommended. Brown University provided the theoretical basis for the hybrid study. A modified version of the Lawrence Berkeley Livermore GEOTHM Program is the major analytical tool used in the analysis. The Intermountain Power Project is the reference all coal-fired plant. Costing methods followed recommendations issued by the Energy research and Development Administration.

  10. 3D Magnetotelluric characterization of the COSO GeothermalField

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Gregory A.; Hoversten, Michael; Gasperikova, Erika; Wannamaker, Philip E.

    2005-01-01

    Knowledge of the subsurface electrical resistivity/conductivity can contribute to a better understanding of complex hydrothermal systems, typified by Coso geothermal field, through mapping the geometry (bounds and controlling structures) over existing production. Three-dimensional magnetotelluric (MT) inversion is now an emerging technology for characterizing the resistivity structures of complex geothermal systems. The method appears to hold great promise, but histories exploiting truly 3D inversion that demonstrate the advantages that can be gained by acquiring and analyzing MT data in three dimensions are still few in number. This project will address said issue, by applying 3D MT forward modeling and inversion to a MT data set acquired over the Coso geothermal field. The goal of the project is to provide the capability to image large geothermal reservoirs in a single self-consistent model. Initial analysis of the Coso MT data has been carried out using 2D MT imaging technology to construct an initial 3D resistivity model from a series of 2D resistivity images obtained using the inline electric field measurements (Zxy impedance elements) along different measurement transects. This model will be subsequently refined through a 3D inversion process. The initial 3D resistivity model clearly shows the controlling geological structures possibly influencing well production at Coso. The field data however, also show clear three dimensionality below 1 Hz, demonstrating the limitations of 2D resistivity imaging. The 3D MT predicted data arising from this starting model show good correspondence in dominant components of the impedance tensor (Zxy and Zyx) above 1Hz. Below 1 Hz there is significant differences between the field data and the 2D model data.

  11. An approach for geochemical assessment of Chipilapa geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Nieva, D.; Verma, M.P.; Portugal, E.; Torres, V.

    1993-01-28

    It presents a systematic methodology to evaluate the reservoir characteristics of Chipilapa- Ahuachapan geothermal field through the highly diluted natural manifestations (springs and domestic wells) in its surroundings. The manifestations are classified in three main groups according to their mechanism of formation: high salinity water (HSW), medium salinity water (MSW), and Sulfated Water (SW). The reservoir temperature at Chipilapa geothermal field is around 220°C which is estimated with application of various chemical geothermometers. The isotopic studies indicate that the heating of local meteoric water with the separated steam of deep reservoir fluids is a dominating process in the formation of springs and domestic wells fluids. The process of formation of primary and secondary vapor explains the isotopic composition of fumaroles.

  12. Recency of Faulting and Neotechtonic Framework in the Dixie Valley Geothermal Field and Other Geothermal Fields of the Basin and Range

    Energy Technology Data Exchange (ETDEWEB)

    Steven Wesnousky; S. John Caskey; John W. Bell

    2003-02-20

    We studied the role that earthquake faults play in redistributing stresses within in the earths crust near geothermal fields. The geographic foci of our study were the sites of geothermal plants in Dixie Valley, Beowawe, and Bradys Hot Springs, Nevada. Our initial results show that the past history of earthquakes has redistributed stresses at these 3 sites in a manner to open and maintain fluid pathways critical for geothermal development. The approach developed here during our pilot study provides an inexpensive approach to (1) better define the best locations to site geothermal wells within known geothermal fields and (2) to define the location of yet discovered geothermal fields which are not manifest at the surface by active geothermal springs. More specifically, our investigation shows that induced stress concentrations at the endpoints of normal fault ruptures appear to promote favorable conditions for hydrothermal activity in two ways. We conclude that an understanding of the spatial distribution of active faults and the past history of earthquakes on those faults be incorporated as a standard tool in geothermal exploration and in the siting of future boreholes in existing geothermal fields.

  13. The Geysers Geothermal Field Update1990/2010

    Energy Technology Data Exchange (ETDEWEB)

    Brophy, P.; Lippmann, M.; Dobson, P.F.; Poux, B.

    2010-10-01

    In this report, we have presented data in four sections: (1) THE GEYSERS HISTORICAL UPDATE 1990-2010 - A historical update of the primary developments at The Geysers between 1990 and 2010 which uses as its start point Section IIA of the Monograph - 'Historical Setting and History of Development' that included articles by James Koenig and Susan Hodgson. (2) THE GEYSERS COMPREHENSIVE REFERENCE LIST 1990-2010 - In this section we present a rather complete list of technical articles and technical related to The Geysers that were issued during the period 1990-2010. The list was compiled from many sources including, but not limited to scientific journals and conference proceedings. While the list was prepared with care and considerable assistance from many geothermal colleagues, it is very possible that some papers could have been missed and we apologize to their authors in advance. The list was subdivided according to the following topics: (1) Field characterization; (2) Drilling; (3) Field development and management; (4) Induced seismicity; (5) Enhanced Geothermal Systems; (6) Power production and related issues; (7) Environment-related issues; and (8) Other topics. (3) GRC 2010 ANNUAL MEETING GEYSERS PAPERS - Included in this section are the papers presented at the GRC 2010 Annual Meeting that relate to The Geysers. (4) ADDITIONAL GEYSERS PAPERS 1990-2010 - Eighteen additional technical papers were included in this publication in order to give a broad background to the development at The Geysers after 1990. The articles issued during the 1990-2010 period were selected by colleagues considered knowledgeable in their areas of expertise. We forwarded the list of references given in Section 2 to them asking to send us with their selections with a preference, because of limited time, to focus on those papers that would not require lengthy copyright approval. We then chose the articles presented in this section with the purpose of providing the broadest possible

  14. Interstratified Illite/Montmorillonite in Kamojang Geothermal Field, Indonesia

    Directory of Open Access Journals (Sweden)

    D. F. Yudiantoro

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v8i4.167Kamojang geothermal field located in West Java Province, falls under the Pangkalan Subregency, Bandung Regency. The researched area is a geothermal field located in the Quaternary volcanic caldera system of about 0.452 to 1.2 Ma. The volcanic activity generated hydrothermal fluids, interacting with rocks producing mineral alteration. The minerals formed in the areas of research are interstratified illite/montmorillonite (I/M. Analyses to identify interstratified I/M have been performed by X-ray diffraction using ethylene glycol, while the determination of the type and percentage of interstratified I/M was based on the calculation method of Watanabe. The methodology was applied on core and cutting samples from Wells KMJ-8, 9, 11, 13, 16, 23, 49, 51, and 54. The result of analysis of the samples shows that the type of clay is interstratified illite/montmorillonite and the minerals are formed at temperatures ranging from 180 to 220° C. The type of interstratified I/M in the studied area is S = 0 and S = 1. The percentage of illite type S = 0 is between 20 - 35% illite, whereas type S = 1 has about 45 - 72% illite. Along with the increasing depth, the percentage of illite is getting greater. This is consistent with the vertical distribution of temperature which increases according to the depth. This correlation results in an interpretation that the upflow zone of the geothermal reservoir is located in the centre of the Kamojang geothermal field.

  15. Interstratified Illite/Montmorillonite in Kamojang Geothermal Field, Indonesia

    Directory of Open Access Journals (Sweden)

    D. F. Yudiantoro

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v8i4.167Kamojang geothermal field located in West Java Province, falls under the Pangkalan Subregency, Bandung Regency. The researched area is a geothermal field located in the Quaternary volcanic caldera system of about 0.452 to 1.2 Ma. The volcanic activity generated hydrothermal fluids, interacting with rocks producing mineral alteration. The minerals formed in the areas of research are interstratified illite/montmorillonite (I/M. Analyses to identify interstratified I/M have been performed by X-ray diffraction using ethylene glycol, while the determination of the type and percentage of interstratified I/M was based on the calculation method of Watanabe. The methodology was applied on core and cutting samples from Wells KMJ-8, 9, 11, 13, 16, 23, 49, 51, and 54. The result of analysis of the samples shows that the type of clay is interstratified illite/montmorillonite and the minerals are formed at temperatures ranging from 180 to 220° C. The type of interstratified I/M in the studied area is S = 0 and S = 1. The percentage of illite type S = 0 is between 20 - 35% illite, whereas type S = 1 has about 45 - 72% illite. Along with the increasing depth, the percentage of illite is getting greater. This is consistent with the vertical distribution of temperature which increases according to the depth. This correlation results in an interpretation that the upflow zone of the geothermal reservoir is located in the centre of the Kamojang geothermal field.

  16. Sustainability analysis of the Ahuachapan geothermal field: management and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Monterrosa, Manuel; Montalvo Lopez, Francisco E. [LaGeo S.A. de C.V., Reservoir Engineering, 15 Av. Sur, Colonia Utila, Santa Tecla, La Libertad (El Salvador)

    2010-12-15

    The Ahuachapan geothermal field (AGF) is located in north western El Salvador. To date, 53 wells (20 producers and 8 injectors) have been drilled in the Ahuachapan geothermal field and the adjacent Chipilapa area. Over the past 33 years, 550 Mtonnes have been extracted from the reservoir, and the reservoir pressure has declined by more than 15 bars. By 1985, the large pressure drawdown due to over-exploitation of the resource reduced the power generation capacity to only 45 MW{sub e}. Several activities were carried out in the period 1997-2005 as part of ''stabilization'' and ''optimization'' projects to increase the electric energy generation to 85 MW{sub e}, with a total mass extraction of 850 kg/s. LaGeo is assessing the sustainability of geothermal reservoir utilization. Preliminary results indicate the planned power production and mass extraction (95 MW, 900 kg/s) cannot be sustained for more than 50 years using current power plant technology. To sustain the exploitation for at least 100 years, the following changes should be implemented: (1) improve the gathering system using large-diameter steam pipelines, (2) expand the exploitation area to the southeast and southwest, and (3) reduce the inlet pressure of the turbines to less than 4 bars. (author)

  17. Analysis of 3d Magnetotelluric Measurements Over the Coso Geothermal Field

    Science.gov (United States)

    Newman, G. A.; Gasperikova, E.; Hoversten, M.

    2007-12-01

    We have carried out an investigation of the Coso Geothermal field utilizing a dense grid of magnetotelluric (MT) stations plus a single line of contiguous bipole array profiling over the east flank of the field. Motivation for this study is that electrical resistivity/conductivity mapping can contribute to better understanding of enhanced geothermal systems (EGS) by imaging the geometry, bounds and controlling structures in existing production, and by monitoring changes in the underground resistivity properties in the vicinity of injection due to fracture porosity enhancement. Initial analysis of the Coso MT data was carried out using 2D MT imaging technology to construct a starting 3D resistivity model from a series of 2D resistivity images obtained using the inline electric field measurements (Zxy impedance elements) along different measurement transects. This model was then refined through a 3D inversion process. The 3D resisitivity model clearly showed the controlling geological structures influencing well production at Coso and shows correlations with mapped surface features such as faults and regional geoelectric strike. We have also correlated the model with an acoustic and shear velocity model of the field to show that the near-vertical high conductivity (low resistivity) structure on the eastern flank of the producing field is also a zone of increase acoustic velocity and increased Vp/Vs ratio.

  18. Geothermal assessment of the lower Bear River drainage and northern East Shore ground-water areas, Box Elder County, Utah

    Energy Technology Data Exchange (ETDEWEB)

    Klauk, R.H.; Budding, K.E.

    1984-07-01

    The Utah Geological and Mineral Survey (UGMS) has been researching the low-temperature geothermal resource potential in Utah. This report, part of an area-wide geothermal research program along the Wasatch Front, concerns the study conducted in the lower Bear River drainage and northern East Shore ground-water areas in Box Elder County, Utah. The primary purpose of the study is to identify new areas of geothermal resource potential. There are seven known low-temperature geothermal areas in this part of Box Elder County. Geothermal reconnaissance techniques used in the study include a temperature survey, chemical analysis of well and spring waters, and temperature-depth measurements in accessible wells. The geothermal reconnaissance techniques identified three areas which need further evaluation of their low-temperature geothermal resource potential. Area 1 is located in the area surrounding Little Mountain, area 2 is west and southwest of Plymouth, and area 3 is west and south of the Cutler Dam. 5 figures, 4 tables.

  19. Exploration of the Rotokawa geothermal field, Taupo volcanic zone, New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Browne, P.R.L. (Univ. of Auckland (New Zealand))

    1988-11-10

    The Rotokawa geothermal field is located 7 km east of Wairakei, New Zealand, and has been investigated for its sulphur resources and power potential over the past 50 years. Exploration of the field has slow and mostly unsystematic. The depths of the drill holes are less than 50 m until 1964. Since 1965 the exploration has been carried out systematically. Three, one and four exploration wells were drilled in 1965-66, 1977, and 1984-86 respectively. Finding Jurassic greywackes and argillites at a depth of 2200 m below a thick (ca. 900 m)sequence of two pyroxene andesite lava flows had an important significance, because the Jurassic rocks are the basement rocks for the North Island. The Rotokawa geothermal field represents an important resource with an assessed potential of 49 MW (proven), 100 MW (probable) and 200 MW (possible), though these figures are considered to be probably optimistic. Further exploratory drilling is needed. The main development problems at this stage are: (1) encountering good subsurface permeability, (2) identifying and combating corrosive CO{sub 2}-rich fluids, (3) determining the most favorable reinjection conditions; this is a problem, ironically enhanced by the hot temperature and the consequently high silica contents of the thermal fluids, (4) establishing an acceptable development plan for the field which accommodates the requirements of both the sulphur mining interests, the power producers, and especially the Ngati Tahu maori owners of the land. 24 refs., 2 figs., 2 tabs.

  20. Hydrothermal surface alteration in the Copahue Geothermal Field (Argentina)

    Energy Technology Data Exchange (ETDEWEB)

    Mas, Graciela R.; Mas, Luis C.; Bengochea, Leandro

    1996-01-24

    In the area of the Copahue Geothermal Field, there are five active geothermal manifestations, which mainly consist of fumaroles, hot springs and mud pots. Four of these manifestations are located in Argentina: Las Máquinas, Termas de Copahue, Las Maquinitas and El Anfiteatro, and the fifth on the Chilean side: Chancho Co. All of them present a strong acid sulfate country rock alteration, characterized by the assemblage alunite + kaolinite + quartz + cristobalite + pyrite + sulfur + jarosite, as the result of the base leaching by fluids concentrated in H2SO4 by atmospheric oxidation at the water table in a steam heated environment of H2S released by deeper boiling fluids. Another alteration zone in this area, called COP-2, is a fossil geothermal manifestation which shows characteristics of neutral to alkaline alteration represented mainly by the siliceous sinter superimposed over the acid alteration. The mineralogy and zoning of these alteration zones, and their relation with the hidrothermal solutions and the major structures of the area are analized.

  1. What lies beneath the Cerro Prieto geothermal field?

    Energy Technology Data Exchange (ETDEWEB)

    Elders, W.A.; Williams, A.E.; Biehler, S. [Univ. of California, Riverside, CA (United States)

    1997-12-31

    Although the Cerro Prieto geothermal reservoir is one of the world`s largest geothermal developments, conflicting ideas persist about the basement beneath it. The current plan to drill a 6 km deep exploratory well in the eastern part of the field has brought this controversy into sharper focus. This paper discusses criteria which any model of what lies beneath the reservoir must meet, in terms of regional tectonics and geophysics, of the metamorphic and igneous rocks thus far encountered in drilling, and of models of possible heat sources and coupling between the hydrothermal and magmatic systems. Our analysis confirms the interpretation that the crystalline basement beneath the sediments, rather than being granitic, is oceanic in character, resembling an ophiolite complex. The heat source is most likely a cooling gabbroic intrusion, several kilometers in diameter, overlain by a sheeted dike swarm. A 6 km deep bore-hole centered over such an intrusion would not only be one of the world`s deepest geothermal wells but could also be one of the hottest.

  2. Seismicity and coupled deformation modeling at the Coso Geothermal Field

    Science.gov (United States)

    Kaven, J. O.; Hickman, S. H.; Davatzes, N. C.

    2015-12-01

    Micro-seismicity in geothermal reservoirs, in particular in enhanced geothermal systems (EGS), is a beneficial byproduct of injection and production, as it can indicate the generation of high-permeability pathways on either pre-existing or newly generated faults and fractures. The hazard of inducing an earthquake large enough to be felt at the surface, however, is not easily avoided and has led to termination of some EGS projects. To explore the physical processes leading to permeability creation and maintenance in geothermal systems and the physics of induced earthquakes , we investigated the evolution of seismicity and the factors controlling the migration, moment release rate, and timing of seismicity in the Coso Geothermal Field (CGF). We report on seismicity in the CGF that has been relocated with high precision double-difference relocation techniques and simultaneous velocity inversions to understand hydrologic reservoir compartmentalization and the nature of subsurface boundaries to fluid flow. We find that two distinct compartments are present within the CGF, which are divided by an aseismic gap showing a relatively low Vp/Vs ratio, likely indicating lower temperatures or lower pore pressures within the gap than in the adjacent reservoir compartments. Well-located events with Mw> 3.5 tend to map onto reactivated fault structures that were revealed when imaged by the relocated micro-seismicity. We relate the temporal and spatial migration of moment release rate to the injection and production histories in the reservoir by employing a thermo-poro-elastic finite element model that takes into account the compartment boundaries defined by the seismicity. We find that pore pressure effects alone are not responsible for the migration of seismicity and that poro-elastic and thermo-elastic stress changes are needed in addition to fluid pressure effects to account for the observed moment release rates.

  3. Pressure Buildup Analysis for Two-Phase Geothermal Wells: Application to the Baca Geothermal Field

    Science.gov (United States)

    Riney, T. D.; Garg, S. K.

    1985-03-01

    The recently published pressure transient analysis methods for two-phase geothermal wells are employed to analyze the pressure buildup data for several wells located in the Redondo Creek area of the Baca geothermal field in New Mexico. The downhole drilling information and pressure/temperature surveys are first interpreted to locate zones at which fluid enters the well bore from the formation and to estimate the initial reservoir temperature and pressure in these zones. All of the Baca wells considered here induced flashing in the formation upon production. Interpretation of the buildup data for each well considers well bore effects (e.g., phase change in the well bore fluid and location of the pressure sensor with respect to the permeable horizon) and the carbon dioxide content of the fluid and its effects on the phase behavior of the reservoir fluids and differentiates between the single- and two-phase portions of the pressure buildup data. Different straight-line approximations to the two portions (i.e., single- and two-phase) of the data on the Homer plot are used to obtain corresponding estimates for the single- and two-phase mobilities. Estimates for the formation permeability-thickness (kH) product are also given.

  4. A database for The Geysers geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Bodvarsson, G.S.; Cox, B.L.; Fuller, P.; Ripperda, M.; Tulinius, H.; Witherspoon, P.A.; Goldstein, N.; Flexser, S.; Pruess, K. (Lawrence Berkeley Lab., CA (USA)); Truesdell, A. (Geological Survey, Menlo Park, CA (USA))

    1989-09-01

    In Fiscal Year 1985-1986 the Earth Sciences Division of Lawrence Berkeley Laboratory (LBL) began a multi-year project for SLC to organize and analyze the field data from The Geysers. In the first year, most of the work concentrated on the development of a comprehensive database for The Geysers, and conventional reservoir engineering analysis of the data. Essentially, all non-proprietary data for wells at The Geysers have been incorporated into the database, as well as proprietary data from wells located on State leases. In following years, a more detailed analysis of The Geysers data has been carried out. This report is a summary of the non- proprietary work performed in FY 1985--1986. It describes various aspects of the database and also includes: review sections on Field Development, Geology, Geophysics, Geochemistry and Reservoir Engineering. It should be emphasized that these background chapters were written in 1986, and therefore only summarize the information available at that time. The appendices contain individual plots of wellhead pressures, degree of superheat, steam flow rates, cumulative mass flows, injection rates and cumulative injection through 1988 for approximately 250 wells. All of the data contained in this report are non-proprietary, from State and non-State leases. The production/injection and heat flow data from the wells were obtained from the California State Division of Oil and gas (DOG) (courtesy of Dick Thomas). Most of the other data were obtained from SLC files in Sacramento (courtesy of Charles Priddy), or DOG files in Santa Rosa (courtesy of Ken Stelling). 159 refs., 23 figs., 3 tabs.

  5. Landslide hazard assessment and mitigation measures in Philippine geothermal fields

    Energy Technology Data Exchange (ETDEWEB)

    Leynes, R.D.; Pioquinto, W.P.C.; Caranto, J.A. [PNOC Energy Development Corporation, Fort Bonifacio (Philippines)

    2005-04-01

    Simple, yet reliable, field criteria have been developed and are being used to qualitatively assess slope instability and slope failure potential in Philippine geothermal fields. Based on a hazard assessment classification of slopes along corridor facilities, sites for implementation of engineering measures are selected. Two case studies are presented. In Mindanao field, the ''very high-risk'' classification of an area resulted in the installation of pipe shelters, which subsequently shielded a section of a pipeline from landslides. Follow-up monitoring is also conducted using cheap, locally fabricated tools, such as surface extensometers. This is being done in Leyte field, where a landslide has threatened a transmission line tower. (author)

  6. Fractal analysis of pressure transients in the Geysers Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Acuna, J.A.; Ershaghi, I.; Yortsos, Y.C.

    1992-01-01

    The conventionally accepted models for the interpretation of pressure transient tests in naturally fractured reservoirs usually involve simplistic assumptions regarding the geometry and transport properties of the fractured medium. Many single well tests in this type of reservoirs fail to show the predicted behavior for dual or triple porosity or permeability systems and cannot be explained by these models. This paper describes the application of a new model based on a fractal interpretation of the fractured medium. The approach, discussed elsewhere [2], [6], is applied to field data from The Geysers Geothermal Field. The objective is to present an alternative interpretation to well tests that characterizes the fractured medium in a manner more consistent with other field evidence. The novel insight gained from fractal geometry allows the identification of important characteristics of the fracture structure that feeds a particular well. Some simple models are also presented that match the field transient results.

  7. Development of a geothermal resource in a fractured volcanic formation: Case study of the Sumikawa Geothermal Field, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Garg, S.K.; Pritchett, J.W.; Stevens, J.L.; Luu, L. [Maxwell Federal Div., Inc., San Diego, CA (United States); Combs, J. [Geo-Hills Associates, Los Altos, CA (United States)

    1996-11-01

    The principal purpose of this case study of the Sumikawa Geothermal Field is to document and to evaluate the use of drilling logs, surface and downhole geophysical measurements, chemical analyses, and pressure transient data for the assessment of a high temperature volcanic geothermal field. The work accomplished during Year 1 of this ongoing program is described in the present report. A brief overview of the Sumikawa Geothermal Field is given. The drilling information and downhole pressure, temperature, and spinner surveys are used to determine feedzone locations, pressures and temperatures. Available injection and production data from both slim holes and large-diameter wells are analyzed to evaluate injectivity/productivity indices and to investigate the variation of discharge rate with borehole diameter. Finally, plans for future work are outlined.

  8. Geothermal reservoir monitoring by continuous self-potential measurements, Mori geothermal field, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Yasukawa, Kasumi; Ishido, Tsuneo [Geological Survey of Japan, AIST, Central 7, Tsukuba, Ibaraki 305-8567 (Japan); Suzuki, Iwao [JMC Geothermal Engineering Co. Ltd, Iwate (Japan)

    2005-10-01

    A self-potential (SP) monitoring study was conducted at the Mori geothermal field, Japan, to detect fluid flow changes in the reservoir caused by well operations. In 2000, eight observation points were deployed in and around the reservoir region for about 2.5 months, during which the production and reinjection wells were shut in and then re-opened. Since no reliable remote reference was available, the SP results were plotted in two ways: adopting an observation point in the target area as reference, and using the average value of all the observation points as a reference (called the 'relative SP' plot). Although changes in SP corresponding to well operations were detected in both plots, more reliable results were obtained with the relative SP plot. Based on numerical simulation of SP using a simplified model of the Mori reservoir, the observed changes are interpreted as being caused by reservoir pressure changes through electrokinetic coupling. (author)

  9. “Climate change, geothermal and development in East Africa” : Notice

    OpenAIRE

    Hazard, Benoit; Adongo, Christine

    2015-01-01

    Hazard, B & Adongo, C " Climate change, geothermal and development in East Africa " , version anglaise du texte publié en français sous le titre « La géothermie : entre développement et énergie verte en Afrique de l'Est », in COP 21 Déprogrammer l'apocalypse, ss. dir. de Raymond Woessner, éditions Atlande, 2015.; English version of a notice published in frenc in « La géothermie : entre développement et énergie verte en Afrique de l'Est », in COP 21 Déprogrammer l'apocalypse, ss. dir. de Raymo...

  10. Mechanisms of formation damage in matrix-permeability geothermal wells

    Energy Technology Data Exchange (ETDEWEB)

    Bergosh, J.L.; Wiggins, R.B.; Enniss, D.O.

    1982-04-01

    Tests were conducted to determine mechanisms of formation damage that can occur in matrix permeability geothermal wells. Two types of cores were used in the testing, actual cores from the East Mesa Well 78-30RD and cores from a fairly uniform generic sandstone formation. Three different types of tests were run. The East Mesa cores were used in the testing of the sensitivity of core to filtrate chemistry. The tests began with the cores exposed to simulated East Mesa brine and then different filtrates were introduced and the effects of the fluid contrast on core permeability were measured. The East Mesa cores were also used in the second series of tests which tested formation sandstone cores were used in the third test series which investigated the effects of different sizes of entrained particles in the fluid. Tests were run with both single-particle sizes and distributions of particle mixes. In addition to the testing, core preparation techniques for simulating fracture permeability were evaluated. Three different fracture formation mechanisms were identified and compared. Measurement techniques for measuring fracture size and permeability were also developed.

  11. Anomalously High Geothermal Gradients in the Buckman Well Field, Santa Fe County, New Mexico

    Science.gov (United States)

    Pollack, A.; Munda, R.; Farrell, T. F.; Kelley, S. A.; Frost, J.; Jiracek, G. R.

    2013-12-01

    Temperature as a function of depth was measured in ten wells in the Santa Fe, NM area as part of the Summer of Applied Geophysics Experience (SAGE) program. Eight of the wells are within 5.5 km of the city's Buckman municipal well field and two wells are at La Tierra, 16.5 km to the SE. Geothermal gradients increase from east to west towards the Buckman area, from 20°C/km at La Tierra to 76°C/km at Buckman. Within the Buckman well field, two wells on its eastern side were determined to have temperature gradients of 32°C/km and 42°C/km. Only 300 m west, the geothermal gradient sharply increases, and measured gradients reach 76 °C/km (well number SF4A), 62°C/km (SF4B), and 68°C/km (SF3A) in three shallow (<100 m) monitoring drill holes. Both local and regional causes may explain the geothermal anomaly. The short spatial wavelength of the horizontal gradient increase argues for a localized source. The unusually high gradients in three of the wells may be associated with fault-controlled, effective shallow-source, warm water upflow or with lateral flow in a shallow aquifer. On the regional level, the east to west increase in temperature gradients can be explained by deep circulating groundwater flow in the Espanola Basin and upwelling near the Rio Grande. Another possible explanation comes from gravity data gathered by SAGE over several years that shows a local NW-striking structural high in the area that could force localized convective upflow. Regional aeromag maps indicate magnetic lows exactly underneath the anomalous wells. These may be interpreted as buried volcanic plugs beneath the Buckman well field, acting as conduits for upwelling warmer waters. They may also indicate hydrothermally altered rock beneath the surface. A more nontraditional cause of the sharp thermal anomaly is also possible. The geothermal gradient anomaly coincides with the dramatic discovery by InSAR in 1993-2000 of localized ground subsidence due to excessive water well pumping

  12. Origin of first cells at terrestrial, anoxic geothermal fields.

    Science.gov (United States)

    Mulkidjanian, Armen Y; Bychkov, Andrew Yu; Dibrova, Daria V; Galperin, Michael Y; Koonin, Eugene V

    2012-04-01

    All cells contain much more potassium, phosphate, and transition metals than modern (or reconstructed primeval) oceans, lakes, or rivers. Cells maintain ion gradients by using sophisticated, energy-dependent membrane enzymes (membrane pumps) that are embedded in elaborate ion-tight membranes. The first cells could possess neither ion-tight membranes nor membrane pumps, so the concentrations of small inorganic molecules and ions within protocells and in their environment would equilibrate. Hence, the ion composition of modern cells might reflect the inorganic ion composition of the habitats of protocells. We attempted to reconstruct the "hatcheries" of the first cells by combining geochemical analysis with phylogenomic scrutiny of the inorganic ion requirements of universal components of modern cells. These ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K(+), Zn(2+), Mn(2+), and phosphate. Thus, protocells must have evolved in habitats with a high K(+)/Na(+) ratio and relatively high concentrations of Zn, Mn, and phosphorous compounds. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapor-dominated zones of inland geothermal systems. Under the anoxic, CO(2)-dominated primordial atmosphere, the chemistry of basins at geothermal fields would resemble the internal milieu of modern cells. The precellular stages of evolution might have transpired in shallow ponds of condensed and cooled geothermal vapor that were lined with porous silicate minerals mixed with metal sulfides and enriched in K(+), Zn(2+), and phosphorous compounds.

  13. Shear velocity of the Rotokawa geothermal field using ambient noise

    Science.gov (United States)

    Civilini, F.; Savage, M. K.; Townend, J.

    2014-12-01

    Ambient noise correlation is an increasingly popular seismological technique that uses the ambient seismic noise recorded at two stations to construct an empirical Green's function. Applications of this technique include determining shear velocity structure and attenuation. An advantage of ambient noise is that it does not rely on external sources of seismic energy such as local or teleseismic earthquakes. This method has been used in the geothermal industry to determine the depths at which magmatic processes occur, to distinguish between production and non-production areas, and to observe seismic velocity perturbations associated with fluid extraction. We will present a velocity model for the Rotokawa geothermal field near Taupo, New Zealand, produced from ambient noise cross correlations. Production at Rotokawa is based on the "Rotokawa A" combined cycle power station established in 1997 and the "Nga Awa Purua" triple flash power plant established in 2010. Rotokawa Joint Venture, a partnership between Mighty River Power and Tauhara North No. 2 Trust currently operates 174 MW of generation at Rotokawa. An array of short period seismometers was installed in 2008 and occupies an area of roughly 5 square kilometers around the site. Although both cultural and natural noise sources are recorded at the stations, the instrument separation distance provides a unique challenge for analyzing cross correlations produced by both signal types. The inter-station spacing is on the order of a few kilometers, so waves from cultural sources generally are not coherent from one station to the other, while the wavelength produced by natural noise is greater than the station separation. Velocity models produced from these two source types will be compared to known geological models of the site. Depending on the amount of data needed to adequately construct cross-correlations, a time-dependent model of velocity will be established and compared with geothermal production processes.

  14. Geochemical evidence of drawdown in the Cerro Prieto geothermal field

    Science.gov (United States)

    Truesdell, A.H.; Manon, M.A.; Jimenez, S.M.E.; Sanchez, A.A.; Fausto, L.J.J.

    1979-01-01

    Some wells of the Cerro Prieto geothermal field have undergone changes in the chemistry of fluids produced which reflect reservoir processes. Pressure decreases due to production in the southeastern part of the field have produced both drawdown of lower chloride fluids from an overlying aquifer and boiling in the aquifer with excess steam reaching the wells. These reservoir changes are indicated by changes in fluid chloride concentrations, Na/K ratios and measured enthalpies and by comparisons of aquifer fluid temperatures and chloride concentrations calculated from enthalpy and chemical measurements. Fluid temperatures have not been greatly affected by this drawdown because heat contained in the rock was transferred to the fluid. When this heat is exhausted, fluid temperatures may drop rapidly. ?? 1979.

  15. Reservoir engineering studies of the Cerro Prieto geothermal field

    Science.gov (United States)

    Goyal, K. P.; Lippmann, M. J.; Tsang, C. F.

    1982-09-01

    Reservoir engineering studies of the Cerro Prieto geothermal field began in 1978 under a five-year cooperative agreement between the US Department of Energy and the Comision Federal de Electricidad de Mexico, with the ultimate objective of simulating the reservoir to forecast its production capacity, energy longevity, and recharge capability under various production and injection scenarios. During the fiscal year 1981, attempts were made to collect information on the evolution history of the field since exploitation began; the information is to be used later to validate the reservoir model. To this end, wellhead production data were analyzed for heat and mass flow and also for changes in reservoir pressures, temperatures, and saturations for the period from March 1973 to November 1980.

  16. Geothermal injection treatment: process chemistry, field experiences, and design options

    Energy Technology Data Exchange (ETDEWEB)

    Kindle, C.H.; Mercer, B.W.; Elmore, R.P.; Blair, S.C.; Myers, D.A.

    1984-09-01

    The successful development of geothermal reservoirs to generate electric power will require the injection disposal of approximately 700,000 gal/h (2.6 x 10/sup 6/ 1/h) of heat-depleted brine for every 50,000 kW of generating capacity. To maintain injectability, the spent brine must be compatible with the receiving formation. The factors that influence this brine/formation compatibility and tests to quantify them are discussed in this report. Some form of treatment will be necessary prior to injection for most situations; the process chemistry involved to avoid and/or accelerate the formation of precipitate particles is also discussed. The treatment processes, either avoidance or controlled precipitation approaches, are described in terms of their principles and demonstrated applications in the geothermal field and, when such experience is limited, in other industrial use. Monitoring techniques for tracking particulate growth, the effect of process parameters on corrosion and well injectability are presented. Examples of brine injection, preinjection treatment, and recovery from injectivity loss are examined and related to the aspects listed above.

  17. Exploration and development of the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Lippmann, M.J.; Goldstein, N.E.; Halfman, S.E.; Witherspoon, P.A.

    1983-07-01

    A multidisciplinary effort to locate, delineate, and characterize the geothermal system at Cerro Prieto, Baja California, Mexico, began about 25 years ago. It led to the identification of an important high-temperature, liquid-dominated geothermal system which went into production in 1973. Initially, the effort was undertaken principally by the Mexican electric power agency, the Comision Federal de Electricidad (CFE). Starting in 1977 a group of US organizations sponsored by the US Department of Energy, joined CFE in this endeavor. An evaluation of the different studies carried out at Cerro Prieto has shown that: (1) surface electrical resistivity and seismic reflection surveys are useful in defining targets for exploratory drilling; (2) the mineralogical studies of cores and cuttings and the analysis of well logs are important in designing the completion of wells, identifying geological controls on fluid movement, determining thermal effects and inferring the thermal history of the field; (3) geochemical surveys help to define zones of recharge and paths of fluid migration; and (4) reservoir engineering studies are necessary in establishing the characteristics of the reservoir and in predicting its response to fluid production.

  18. Briefing Book, Interagency Geothermal Coordinating Council (IGCC) Meeting of April 28, 1988

    Energy Technology Data Exchange (ETDEWEB)

    None

    1988-04-28

    The IGCC of the U.S. government was created under the intent of Public Law 93-410 (1974) to serve as a forum for the discussion of Federal plans, activities, and policies that are related to or impact on geothermal energy. Eight Federal Departments were represented on the IGCC at the time of this meeting. The main presentations in this report were on: Department of Energy Geothermal R&D Program, the Ormat binary power plant at East Mesa, CA, Potential for direct use of geothermal at Defense bases in U.S. and overseas, Department of Defense Geothermal Program at China Lake, and Status of the U.S. Geothermal Industry. The IGCC briefing books and minutes provide a historical snapshot of what development and impact issues were important at various time. (DJE 2005)

  19. Final design, installation and baseline testing of 500 kW direct contact pilot plant at East Mesa

    Energy Technology Data Exchange (ETDEWEB)

    Hlinak, A.; Lobach, J.; Nichols, K.; Olander, R.; Werner, D.

    1980-05-30

    The pilot plant was configured to accomplish two objectives - first to evaluate the overall performance potential of direct contact powerplants and second to develop design criteria and parameters for full-scale direct contact plants. The pilot plant includes all of the process functions that would be incorporated in a full-scale plant. Incoming brine is treated to remove undissolved gases, pumped through the direct contact heat exchanger (DCHX), and then sent to a recovery system for removal of the dissolved working fluid. The chosen working fluid is isobutane (IC/sub 4/). The working fluid loop includes a radial inflow turbine with generator, condensers, hot-well reservoir, and a feed pump. A downwell pump was installed in the geothermal well to supply the plant with unflashed brine. (MHR)

  20. Remote Sensing Techniques as a Tool for Geothermal Exploration: the Case Study of Blawan Ijen, East Java

    Science.gov (United States)

    Pasqua, Claudio; Verdoya, Massimo

    2014-05-01

    The use of remote sensing techniques in the initial phase of geothermal surveys represents a very cost-effective tool, which can contribute to a successful exploration program. Remote sensing allows the analysis of large surfaces and can lead to a significant improvement of the identification of surface thermal anomalies, through the use of thermal infra red data (TIR), as well as of zones of widespread and recent faulting, which can reflect larger permeability of geological formations. Generally, the fractures analysis from remote sensing can be fundamental to clarify the structural setting of an area. In a regional volcanic framework, it can also help in defining the spatial and time evolution of the different volcanic apparatuses. This paper describes the main results of a remote sensing study, conducted in the Blawan-Ijen volcanic area (East Java), which is at present subject of geothermal exploration. This area is characterized by the presence of a 15 km wide caldera originated by a collapsed strato volcano. This event was followed by the emplacement of several peri-calderic and intra-calderic volcanoes, among which G. Raung, as testified by the frequent occurrence of shallow earthquakes and by H2S emission and sulfur deposition, and G. Kawah Ijen, occurring at the eastern rim of the caldera, are still active. The summit of G. Kawah Ijen volcano consists of two interlocking craters forming an E-W elongated depression filled up by a hyperacidic lake. Along the southern shore of the lake, a small rhyolitic dome occurs, which exhibits strong fumarolic activity with temperature of as much as 600 °C. We performed an analysis based on the combined interpretation of Landsat ETM+7, Aster and Synthetic Aperture Radar (SAR) images, focused on the identification of subsurface high permeability zones. The main trends of the linear features as derived from the fractures analysis, as well as their relation with the distribution of volcanic centres, were identified

  1. Mesa redonda

    Directory of Open Access Journals (Sweden)

    Roberto Lira Olmo

    2015-04-01

    Full Text Available En relación al tema central del presente número de la Revista Urbano, la "Identidad Urbana", el Comité Editorial de la misma estimó en su oportunidad de gran interés reunir en una Mesa Redonda a destacados intelectuales, académicos y profesionales que, de una u otra forma, están vinculados por su trabajo, investigación e inquietudes personales con este apasionante tema del cual existen tantas y tan variadas concepciones.

  2. A reservoir engineering assessment of the San Jacinto-Tizate Geothermal Field, Nicaragua

    Energy Technology Data Exchange (ETDEWEB)

    Ostapenko, S.; Spektor, S.; Davila, H.; Porras, E.; Perez, M.

    1996-01-24

    More than twenty yews have passed since geothermal research and drilling took place at the geothermal fields in Nicaragua- Tbe well horn Momotombo Geothermal Field (70 We) has been generating electricity since 1983, and now a new geothermal field is under exploration. the San Jacinto-Tizate. Two reservoirs hydraulic connected were found. The shallow reservoir (270°C) at the depth of 550 - 1200 meters, and the deep one at > 1600 meters. Both of theme are water dominated reservoirs, although a two phase condition exist in the upper part of the shallow one. Different transient tests and a multi-well interference test have been carried out, very high transmissivity value were estimated around the well SJ-4 and average values for the others. A preliminar conceptual model of the geothermal system is given in this paper, as the result of the geology, geophysics, hydrology studies, drilling and reservoir evaluation.

  3. A reservoir engineering assessment of the San Jacinto-Tizate geothermal field, Nicaragua

    Energy Technology Data Exchange (ETDEWEB)

    Ostapenko, S.; Spektor, S.; Davila, H.; Porras, E.; Perez, M. [INTERGEOTERM, Managua (Nicaragua)

    1996-12-31

    More than twenty years have passed since geothermal research and drilling took place at the geothermal fields in Nicaragua. The well known Momotombo Geothermal Field (70 MWe) has been generating electricity since 1983, and now a new geothermal field is under exploration, the San Jacinto-Tizate. Two reservoirs hydraulic connected were found. The shallow reservoir (270{degrees}C) at the depth of 550 - 1200 meters, and the deep one at > 1600 meters. Both of them are water dominated reservoirs although a two phase condition exist in the upper part of the shallow one. Different transient tests and a multi-well interference test have been carried out, very high transmissivity value were estimated around the well SJ-4 and average values for the others. A preliminary conceptual model of the geothermal system is given in this paper, as the result of the geology, geophysics, hydrology studies, drilling and reservoir evaluation.

  4. Investigation of fault structures from microseismicity in the Wairakei geothermal field, New Zealand

    Science.gov (United States)

    Kim, Jongchan; Boese, Carolin; Andrews, Jennifer; Sepulveda, Favian; Archer, Rosalind; Malin, Peter

    2014-05-01

    The Wairakei geothermal field is located in the centre of a NNE-trending rifting arc, called the Taupo Volcanic Zone (TVZ), New Zealand. In 1958, commercial production of electricity started at the Wairakei field, which currently holds the largest installed capacity of the TVZ (~375 MWe). For some operational reasons, large scale infield re-injection started in the mid 1990's (Otupu area; east of Wairakei) and further extended to the south (Karapiti area) in August 2011. Small scale re-injection trials have been also being conducted since 2012 (West of Wairakei). In total, 13 borehole seismometers have been installed in the Wairakei geothermal field since 2009 to support reservoir management and drilling strategies, and observe the reservoir response to production and injection. The range of installation depths is 65 m to 1,200 m. About 97% of the 7049 events recorded have magnitude ≤2, in the so-called micro-earthquake range, and locate above 6 km depth. The micro-seismicity distribution tends to be diffuse. Although some correlation with geological units and faults can be made, identification of distinct fractures is challenging. In this study, we investigate active fault structures from micro-seismic events occurring in the geothermal field between March 2009 and June 2013 using focal mechanism, clustering and double-difference relocation methods. We firstly calculate double-couple focal mechanism solutions from the micro-seismic data set using HASH. To reduce uncertainty of focal mechanism parameters, P-wave first motion polarities from 12 GeoNet stations installed in the vicinity of the Wairakei were combined with those of 13 Wairakei stations within the field. In total, 21 focal mechanisms with more than eight P-wave polarities have been computed. Most focal mechanisms are consistent in showing a NNE-trending nodal plane, and have normal or strike-slip mechanisms, coinciding well with the overall extensional tectonic regime and mapped active faults in the

  5. Analysis of the Fractures pattern at the Chingshui geothermal field, Taiwan

    Science.gov (United States)

    Lu, C.; Lo, W.; Song, S.

    2010-12-01

    Magma chambers in the shallow crust and shallow intrusive igneous rock result in a high heat flow and geothermal gradient. Hot springs, one of geothermal potential phenomena, is widely distributed in Taiwan, especially in the Slate Belt and Tananao Complex of Central Range. The Slate Belt is mainly composed of meta-sandstone, argillite and slate, which have high porosity for geothermal source reservoirs. While the Tananao Complex is composed of phyllite, schist, gneiss, limestone and amphibolites, which have low porosity, but heat flow can conduct along cleavages, Joints, and other fractures. The purpose of this study is to delineate the fracture pattern and geothermal structure by field geologic survey and joints analysis. The rocks cropping out in the mapped area belong mainly to the Lushan Formation of Miocene age, which can be divided into two members: Chingshuihu member and Jentse member in ascending order. The Chingshuihu member is composed of slate or phyllite with thin beds of metasandstone. The Jentse member is composed of alternation of argillite and metasandstone. The geothermal reservoir of the Chingshui geothermal field might be related to the fault damage zone of the Chingshuihsi fault and Xiaonanao fault. Linking damage zones were caused by the interaction and linkage of fault segments in the geothermal field and developed a wide range of fracture patterns that depend on the nature of the interaction between the two fault segments. The fault damage zone and high porosity of sandstone resulted in well geothermal reservoir. The information obtained from the field geologic survey and Joint analysis indicate that the joint systems could be divided into four sets in terms of the strike and dip. Further, the geothermal reservoir is confined to a zone that extends 800m in width along N30E, 1km in length, and has an 80 dip toward SE. The main geothermal field is found in the NW of the reservoir; this area is located between the Chingshuihsi fault and

  6. Extension of the Cerro Prieto field and zones in the Mexicali Valley with geothermal possibilities in the future

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca L, H.L.; de la Pena L, A.; Puente C, I.; Diaz C, E.

    1981-01-01

    This study concerns the possible extension of the Cerro Prieto field and identification of other zones in the Mexicali Valley with geothermal development potential by assessing the structural geologic conditions in relation to the regional tectonic framework and the integration of geologic and geophysical surveys carried out at Cerro Prieto. This study is based on data obtained from the wells drilled to date and the available geological and geophysical information. With this information, a geologic model of the field is developed as a general description of the geometry of what might be the geothermal reservoir of the Cerro Prieto field. In areas with geothermal potential within the Mexicali Valley, the location of irrigation wells with anomalous temperatures was taken as a point of departure for subsequent studies. Based on this initial information, gravity and magnetic surveys were made, followed by seismic reflection and refraction surveys and the drilling of 1200-m-deep multiple-use wells. Based on the results of the final integration of these studies with the geology of the region, it is suggested that the following areas should be explored further: east of Cerro Prieto, Tulecheck, Riito, Aeropuerto-Algodones, and San Luis Rio Colorado, Sonora.

  7. Isotopic zoning and origin of the aquifers in the discharge area of the geothermal fields of Ahuachapan and Chipilapa, El Salvador

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Vicente Torres; Birkle, Peter; Partida, Eduardo Gonzalez; Nieva, David; Verma, Mahendra Pal; Marin, Enrique Portugal [Instituto de Investigaciones Electricas, Dept. de Geotermia, Cuernavaca, Morelos (Mexico); Castellanos, Federico [Comision Ejecutiva Hidroelectrica del Rio Lempa, GEOCEL, Santa Tecla (El Salvador)

    1997-12-01

    The northern discharge areas of the Ahuachapan and Chipilapa geothermal fields can be subdivided into four different zones based on their structural position, and the isotopic and chemical composition of their waters. In general, the contribution of geothermal waters from these two fields was estimated to be less than 10%. Elevation effects are of little importance, whereas a slight trend towards higher isotopic values with increasing water temperatures may exist. The NNW-SSE-trending Escalante and Agua Caliente faults represents lateral groundwater barriers, and provide vertical conduits for the ascending geothermal waters. The western discharge areas seem to be more influenced by the Ahuachapan geothermal field, whereas those to the east are more influenced by the Chipilapa field. Groundwaters in the Northern Plain are mainly from shallow northward-flowing aquifers. These waters show temperature effects, mixing with geothermal waters and are affected by the geology of the area. However, non of these factors alone can explain the isotopic variations in the waters of the northern discharge areas. (Author)

  8. The Ahuachapan geothermal field, El Salvador: Reservoir analysis

    Energy Technology Data Exchange (ETDEWEB)

    Aunzo, Z.; Bodvarsson, G.S.; Laky, C.; Lippmann, M.J.; Steingrimsson, B.; Truesdell, A.H.; Witherspoon, P.A. (Lawrence Berkeley Lab., CA (USA); Icelandic National Energy Authority, Reykjavik (Iceland); Geological Survey, Menlo Park, CA (USA); Lawrence Berkeley Lab., CA (USA))

    1989-08-01

    The Earth Sciences Division of Lawrence Berkeley Laboratory (LBL) is conducting a reservoir evaluation study of the Ahuachapan geothermal field in El Salvador. This work is being performed in cooperation with the Comision Ejecutiva Hidroelectrica del Rio Lempa (CEL) and the Los Alamos National Laboratory (LANL). This report describes the work done during the first year of the study (FY 1988--89), and includes the (1) development of geological and conceptual models of the field, (2) evaluation of the initial thermodynamic and chemical conditions and their changes during exploitation, (3) evaluation of interference test data and the observed reservoir pressure decline, and (4) the development of a natural state model for the field. The geological model of the field indicates that there are seven (7) major and five (5) minor faults that control the fluid movement in the Ahuachapan area. Some of the faults act as a barrier to flow as indicated by large temperature declines towards the north and west. Other faults act as preferential pathways to flow. The Ahuachapan Andesites provide good horizontal permeability to flow and provide most of the fluids to the wells. The underlying Older Agglomerates also contribute to well production, but considerably less than the Andesites. 84 refs.

  9. Optimization of Field Development Scheduling, East Unity Oil Field, Sudan

    Directory of Open Access Journals (Sweden)

    Tagwa A. Musa

    2005-01-01

    Full Text Available In order to improve the reservoir performance in East Unity oil field Sudan, the studies focused on characterization, modeling and simulation of the actual performance and future development. A model was constructed using a three-phase, three dimensional, black oil simulator (ECLIPSE. In this study a data from East Unity oil field Sudan started production at July 1999 was used to perform the optimal oil rate and designing the best location of the new operating wells. Cumulative oil production, oil production rate, Water cut and recovery factor were used as key criteria to see if adding new wells in the area under study are economic risk.

  10. Full Moment Tensor Analysis at The Geysers Geothermal Field

    Science.gov (United States)

    Boyd, O. S.; Dreger, D. S.; Hellweg, M.; Lombard, P. N.; Ford, S. R.; Taira, T.; Taggart, J.; Weldon, T. J.

    2011-12-01

    Geothermal energy has been produced at The Geysers Geothermal Field in Northern California for more than forty years. It has been demonstrated that increased steam production and fluid injection correlates positively with changes in earthquake activity, resulting in thousands of tiny earthquakes each year with events ranging in magnitude up to 4.5. We determine source parameters for the largest of these earthquakes using a regional distance moment tensor method. We invert three-component, complete waveform data from broadband stations of the Berkeley Digital Seismic Network, the Northern California Seismic Network and the USArray deployment (2005-2007) for the complete, six-element moment tensor. Some solutions depart substantially from a pure double-couple with some events having large volumetric components. Care is needed in the assessment of the significance of the non-double-couple terms. We have worked to develop a systematic procedure for the evaluation of aleatoric and epistemic solution uncertainty (e.g. Ford et al., 2009; Ford et al., 2010). We will present the solutions for The Geysers events together with estimates of random errors and systematic errors due to imperfect station coverage and knowledge of the velocity structure, which are needed to compute Green's functions for the inversion. Preliminary results indicate that some events have large isotropic components that appear to be stable and suggestive of fluid or gas involvement during the rupture processes. We are presently incorporating full moment tensor capability in the Berkeley Seismological Laboratory's automatic processing system and analyst interface. This upgrade will enable improved monitoring at The Geysers and volcanically active regions of California.

  11. Modeling study of the Pauzhetsky geothermal field, Kamchatka, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Kiryukhin, A.V. [Institute of Volcanology, Kamchatsky (Russian Federation); Yampolsky, V.A. [Kamchatskburgeotermia State Enterprise, Elizovo (Russian Federation)

    2004-08-01

    Exploitation of the Pauzhetsky geothermal field started in 1966 with a 5 MW{sub e} power plant. A hydrogeological model of the Pauzhetsky field has been developed based on an integrated analysis of data on lithological units, temperature, pressure, production zones and natural discharge distributions. A one-layer 'well by well' model with specified vertical heat and mass exchange conditions has been used to represent the main features of the production reservoir. Numerical model development was based on the TOUGH2 code [Pruess, 1991. TOUGH2 - A General Purpose Numerical Simulator for Multiphase Fluid and Heat Flow, Lawrence Berkeley National Laboratory Report, Berkeley, CA; Pruess et al., 1999. TOUGH2 User's Guide, Version 2.0, Report LBNL-43134, Lawrence Berkeley National Laboratory, Berkeley, CA] coupled with tables generated by the HOLA wellbore simulator [Aunzo et al., 1991. Wellbore Models GWELL, GWNACL, and HOLA, Users Guide, Draft, 81 pp.]. Lahey Fortran-90 compiler and computer graphical packages (Didger-3, Surfer-8, Grapher-3) were also used to model the development process. The modeling study of the natural-state conditions was targeted on a temperature distribution match to estimate the natural high-temperature upflow parameters: the mass flow-rate was estimated at 220 kg/s with enthalpy of 830-920 kJ/kg. The modeling study for the 1964-2000 exploitation period of the Pauzhetsky geothermal field was targeted at matching the transient reservoir pressure and flowing enthalpies of the production wells. The modeling study of exploitation confirmed that 'double porosity' in the reservoir, with a 10-20% active volume of 'fractures', and a thermo-mechanical response to reinjection (including changes in porosity due to compressibility and expansivity), were the key parameters of the model. The calibrated model of the Pauzhetsky geothermal field was used to forecast reservoir behavior under different exploitation scenarios for

  12. The evaluating of the cost of electric power generation from the first geothermal power plant in Iran (Case Study: Meshkin-Shahr Geothermal Field

    Directory of Open Access Journals (Sweden)

    Mousazadeh , B

    2016-12-01

    Full Text Available Iran has fourteen vast areas with good potential for geothermal utilization. One such area is the Meshkin-Shahr geothermal field. Ten exploration wells and one injection well have been drilled to determine the parameters of the reservoir. In this paper, we considered the possibility of installing 55 MW geothermal power plant in Meshkin-Shahr near Sabalan Mt in the north-west of Iran. The Renewable Energies Organization of Iran (SUNA are trying to develop Meshkinshahr geothermal field to startup the first double flash geothermal power plant. In this pape, the technical and economical parameters due to installing 55 MW geothermal power plant was considered for meshkin- shahr geothermal field. Three scenarios; minimum, mean, maximum have been explored respectively to estimate the cost of power generation in Meshkin-Shahr geothermal power plant. The results of these calculations have been classified in some tables and shows that it will be economical to generate 55 MWe from Meshkin-Shahr geothermal power plant

  13. Innovative approach for risk assessment in green field geothermal project

    NARCIS (Netherlands)

    Batini, F.; Wees, J.-D. van

    2010-01-01

    At present, the worldwide geothermal energy production provides less than 1% of the world's energy needs but the geothermal resources confined in the first 6 km of the earth's crust are estimated to be in the fairly above 200 GW of which 50-80 GW are located in Europe. Exploring and developing at

  14. Gas chemistry and thermometry of the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Nehring, N.L. (US Geological Survey, Menlo Park, CA); D' Amore, F.

    1981-01-01

    Geothermal gases at Cerro Prieto are derived from high temperature reactions within the reservoir or are introduced with recharge water. Gases collected from geothermal wells should, therefore, reflect reservoir conditions. Interpretation of gas compositions of wells indicates reservoir temperatures, controls of oxygen and sulfur fugacities, and recharge source and direction.

  15. Innovative approach for risk assessment in green field geothermal project

    NARCIS (Netherlands)

    Batini, F.; Wees, J.-D. van

    2010-01-01

    At present, the worldwide geothermal energy production provides less than 1% of the world's energy needs but the geothermal resources confined in the first 6 km of the earth's crust are estimated to be in the fairly above 200 GW of which 50-80 GW are located in Europe. Exploring and developing at la

  16. Hydrogeology of the Owego-Apalachin Elementary School Geothermal Fields, Tioga County, New York

    Science.gov (United States)

    Williams, John H.; Kappel, William M.

    2015-12-22

    The hydrogeology of the Owego-Apalachin Elementary School geothermal fields, which penetrate saline water and methane in fractured upper Devonian age bedrock in the Owego Creek valley, south-central New York, was characterized through the analysis of drilling and geophysical logs, water-level monitoring data, and specific-depth water samples. Hydrogeologic insights gained during the study proved beneficial for the design of the geothermal drilling program and protection of the overlying aquifer during construction, and may be useful for the development of future geothermal fields and other energy-related activities, such as drilling for oil and natural gas in similar fractured-bedrock settings.

  17. Plate boundary deformation and man-made subsidence around geothermal fields on the Reykjanes Peninsula, Iceland

    KAUST Repository

    Keiding, Marie

    2010-07-01

    We present Interferometric Synthetic Aperture Radar (InSAR) data from 1992-1999 and 2003-2008 as well as GPS data from 2000-2009 for the active plate boundary on the Reykjanes Peninsula, southwest Iceland. The geodetic data reveal deformation mainly due to plate spreading, anthropogenic subsidence caused by geothermal fluid extraction and, possibly, increasing pressure in a geothermal system. Subsidence of around 10. cm is observed during the first 2. years of production at the Reykjanes geothermal power plant, which started operating in May 2006. We model the surface subsidence around the new power plant using point and ellipsoidal pressure sources in an elastic halfspace. Short-lived swarms of micro-earthquakes as well as aseismic fault movement are observed near the geothermal field following the start of production, possibly triggered by the stresses induced by geothermal fluid extraction. © 2010 Elsevier B.V.

  18. Numerical Studies of the Heat and Mass Transport in the Cerro Prieto Geothermal Field, Mexico

    Science.gov (United States)

    Lippmann, M. J.; Bodavarsson, G. S.

    1983-06-01

    Numerical simulation techniques are employed in studies of the natural flow of heat and mass through the Cerro Prieto reservoir, Mexico and of the effects of exploitation on the field's behavior. The reservoir model is a two-dimensional vertical east to west-southwest cross section, which is based on a recent hydrogeologic model of this geothermal system. The numerical code MULKOM is used in the simulation studies. The steady state pressure and temperature distributions are computed and compared against observed preproduction pressures and temperatures; a reasonable match is obtained. A natural hot water recharge rate of about 1×10-2 kg/s per meter of field length (measured in a north-south direction) is obtained. The model is then used to simulate the behavior of the field during the 1973-1978 production period. The response of the model to fluid extraction agrees to what has been observed in the field or postulated by other authors. There is a decrease in temperatures and pressures in the produced region. No extensive two-phase zone develops in the reservoir because of the strong fluid recharge. Most of the fluid recharging the system comes from colder regions located above and west of the produced reservoir.

  19. Discovery and geology of the Desert Peak geothermal field: a case history. Bulletin 97

    Energy Technology Data Exchange (ETDEWEB)

    Benoit, W.R.; Hiner, J.E.; Forest, R.T.

    1982-09-01

    A case history of the exploration, development (through 1980), and geology of the Desert Peak geothermal field is presented. Sections on geochemistry, geophysics, and temperature-gradient drilling are included.

  20. Subsurface Characterization Beneath the Coso Geothermal Field by Ambient Noise Tomography

    Science.gov (United States)

    Ritzwoller, M. H.; Yang, Y.; Levshin, A. L.; Barmin, M. P.; Jones, C. H.

    2009-12-01

    The Coso Geothermal Area has been the subject of numerous geophysical studies over the past 30 years. Various seismological techniques have been applied to evaluate the regional stress distribution, velocity and attenuation structure of the subsurface. None of these studies has imaged subsurface shear velocity using surface waves generated either by local micro-earthquakes or by regional or teleseismic earthquakes, nor have any used interferometric methods based on ambient noise. In this study, we apply an interferometic method based on ambient seismic noise aimed at imaging the shallow shear velocity structure beneath the Coso Geothermal Area. Data are from a PASSCAL experiment deployed between 1998 and 2000 and regional broad-band seismometers operated by CalTech. Cross-correlations are performed between each pair of the COSO PASSCAL and CalTech stations for 15 months from March 1999 to May 2000. After compensating for or correcting instrumental irregularities and selecting reliable Rayleigh wave dispersion measurements from the inter-station cross-correlations, we obtain about 300 measurement paths as the basis for surface wave tomography at periods from 3 to 10 sec. Uncertainties of both group and phase velocity measurements are estimated using the variations among the dispersion curves from one-month cross-correlations in different months. The resulting dispersion maps reveal low group and phase velocities in the COSO volcanic field, especially at 3 sec period for group velocities, and high velocities to the east of the COSO volcanic field. The velocity variations are consistent with surface geological features, which encourages future inversion for 3-D shear velocity structure in the top 15 km of the crust.

  1. Regional Geothermal Characterisation of East Anatolia from Aeromagnetic, Heat Flow and Gravity Data

    Science.gov (United States)

    Bektaş, Özcan; Ravat, Dhananjay; Büyüksaraç, Aydin; Bilim, Funda; Ateş, Abdullah

    2007-05-01

    East Anatolia is a region of high topography made up of a 2-km high plateau and Neogene and Quaternary volcanics overlying the subduction-accretion complex formed by the process of collision. The aeromagnetic and gravity data surveyed by the Mineral Research and Exploration (MTA) of Turkey have been used to interpret qualitatively the characteristics of the near-surface geology of the region. The residual aeromagnetic data were low-pass filtered and analyzed to produce the estimates of magnetic bottom using the centroid method and by forward modelling of spectra to evaluate the uncertainties in such estimates. The magnetic bottom estimates can be indicative of temperatures in the crust because magnetic minerals lose their spontaneous magnetization at the Curie temperature of the dominant magnetic minerals in the rocks and, thus, also are called Curie point depths (CPDs). The Curie point depths over the region of Eastern Anatolia vary from 12.9 to 22.6 km. Depths computed from forward modelling of spectra with 200 600 km window sizes suggest that the bottom depths from East Anatolia from the magnetic data may have errors exceeding 5 km; however, most of the obtained depths appear to lie in the above range and indicate that the lower crust is either demagnetized or non-magnetic. In the interpretation of the magnetic map, we also used reduction-to-pole (RTP) and amplitude of total gradient of high-pass filtered anomalies, which reduced dipolar orientation effects of induced aeromagnetic anomalies. However, the features of the RTP and the total gradient of the high-pass filtered aeromagnetic anomalies are not highly correlated to the hot spring water locations. On the other hand, many high-amplitude features seen on the total gradient map can be correlated with the ophiolitic rocks observed on the surface. This interpretation is supported by Bouguer gravity data. In this paper, we recommend that the sources of the widespread thermal activity seen in East Anatolia must

  2. Identification of fluid-flow paths in the Cerro Prieto geothermal field

    Science.gov (United States)

    Halfman, S. E.; Lippmann, M. J.; Zelwer, R.; Howard, J. H.

    1982-05-01

    A hydrogeologic model of the Cerro Prieto geothermal field has been developed based on geophysical and lithologic well logs, downhole temperature, and well completion data from about 90 deep wells. The hot brines seem to originate in the eastern part of the field, flowing in a westward direction and rising through gaps in the shaly layers which otherwise act as partial caprocks to the geothermal resource.

  3. Seismotectonics of the Cerro Prieto Geothermal Field, Baja California, Mexico.

    Science.gov (United States)

    Rebollar, C. J.; Reyes, L. M.; Quintanar, L.; Arellano, J. F.

    2002-12-01

    We studied the background seismic activity in the Cerro Prieto geothermal field (CPGF) using a network of 21 digital stations. Earthquakes are located below the exploitation area of the CPGF, between 3 and 12 km depth, within the basement. Earthquakes follow roughly a N30°E trend perpendicular to the Cerro Prieto fault. This activity is located on a horst-like structure below the geothermal field and coincides with the zone of maximum subsidence in the CPGF. Two earthquake swarms occurred along the SE-NW strike of the Cerro Prieto fault and in the neighborhood of the Cerro Prieto volcano. Magnitudes range from -0.3 to 2.5. A Vp/Vs=1.91 ratio of the activity below the volcano suggests a water-saturated medium and/or a partial-melt medium. We calculated 76 focal mechanisms of individual events. On June 1 and September 10, 1999, two earthquakes of Mw 5.2 and 5.3 occurred in the basement at depths of 7.4 and 3.8 km below the CPGF. Maximum peak accelerations above the hypocenter ranged from 128.0 to 432.0 cm/s2. Waveform modeling results in a fault geometries given by strike=236°, dip=60°, rake=-58° (normal) and strike=10°, dip=90°, rake=159° (right lateral strike-slip) for the June and September events. Observed triangular source time function of 0.7 seconds and a double source with a total duration of 1.9 seconds for the June and September events were used to calculate the synthetics seismograms. Static stress drops and seismic moments for the June and September events are: Δ\\sigma=82.5 MPa (825 bars), Mo= 7.65x1016 Nm (7.65x1023 dyne-cm) and Δ\\sigma=31.3 MPa (313 bars) and Mo=1.27x1017 Nm (1.27x1024 dyne-cm). These stress drops are typical of continental events rather than stress drops of events originated in spreading centers. We concluded from the focal mechanisms of the background seismicity and June and September 1999 events, that a complex stress environment exits in the CPGF due to the continual thinning of the crust in the Cerro Prieto basin.

  4. Phase 2 and 3 Slim Hole Drilling and Testing at the Lake City, California Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Dick Benoit; David Blackwell; Joe Moore; Colin Goranson

    2005-10-27

    During Phases 2 and 3 of the Lake City GRED II project two slim holes were cored to depths of 1728 and 4727 ft. Injection and production tests with temperature and pressure logging were performed on the OH-1 and LCSH-5 core holes. OH-1 was permanently modified by cementing an NQ tubing string in place below a depth of 947 ft. The LCSH-1a hole was drilled in Quaternary blue clay to a depth of 1727 ft and reached a temperature of 193 oF at a depth of 1649 ft. This hole failed to find evidence of a shallow geothermal system east of the Mud Volcano but the conductive temperature profile indicates temperatures near 325 oF could be present below depth of 4000 ft. The LCSH-5 hole was drilled to a depth of 4727 ft and encountered a significant shallow permeability between depths of 1443 and 1923 ft and below 3955 ft. LCSH-5 drilled impermeable Quaternary fanglomerate to a depth of 1270 ft. Below 1270 ft the rocks consist primarily of Tertiary sedimentary rocks. The most significant formation deep in LCSH-5 appears to be a series of poikoilitic mafic lava flows below a depth of 4244 ft that host the major deep permeable fracture encountered. The maximum static temperature deep in LCSH-5 is 323 oF and the maximum flowing temperature is 329 oF. This hole extended the known length of the geothermal system by ¾ of a mile toward the north and is located over ½ mile north of the northernmost hot spring. The OH-1 hole was briefly flow tested prior to cementing the NQ rods in place. This flow test confirmed the zone at 947 ft is the dominant permeability in the hole. The waters produced during testing of OH-1 and LCSH-5 are generally intermediate in character between the deep geothermal water produced by the Phipps #2 well and the thermal springs. Geothermometers applied to deeper fluids tend to predict higher subsurface temperatures with the maximum being 382 oF from the Phipps #2 well. The Lake City geothermal system can be viewed as having shallow (elevation > 4000 ft and

  5. Reservoir engineering assessment of Dubti geothermal field, Northern Tendaho Rift, Ethiopia

    Energy Technology Data Exchange (ETDEWEB)

    Battistelli, A.; Ferragina, C. [Aquater S.p.A. (ENI Group), San Lorenzo in Campo (Italy); Yiheyis, A.; Abatneh, W. [Ethiopian Institute of Geological Surveys, Addis Ababa (Ethiopia); Calore, C. [International Institute for Geothermal Research, Pisa (Italy)

    2002-06-01

    Following on from surface exploration surveys performed during the 1970s and early 1980s, exploration drilling was carried out in the Tendaho Rift, in Central Afar (Ethiopia), from October 1993 to June 1995. Three deep and one shallow well were drilled in the central part of the Northern Tendaho Rift to verify the existence of a geothermal reservoir and its possible utilisation for electric power generation. The project was jointly financed by the Ethiopian Ministry of Mines and Energy and the Italian Ministry for Foreign Affairs. Project activities were performed by the Ethiopian Institute of Geological Surveys and Aquater SpA. The main reservoir engineering data discussed in this paper were collected during drilling and testing of the above four wells, three of which are located inside the Dubti Cotton Plantation, in which a promising hydrothermal area was identified by surface exploration surveys. Drilling confirmed the existence of a liquid-dominated shallow reservoir inside the Dubti Plantation, characterised by a boiling -point-for-depth temperature distribution down to about 500 m depth. The main permeable zones in the Sedimentary Sequence, which is made up of lacustrine deposits, are located in correspondence to basalt lava flow interlayerings, or at the contact between volcanic and sedimentary rocks. At depth, the basaltic lava flows that characterise the Afar Stratoid Series seem to have low permeability, with the exception of fractured zones associated with sub-vertical faults. Two different upflows of geothermal fluids have been inferred: one flow connected to the Dubti fault feeds the shallow reservoir crossed by wells TD-2 and TD-4, where a maximum temperature of 245{sup o}C was recorded; the second flow seems to be connected with a fault located east of well TD-1, where the maximum recorded temperature was 270{sup o}C. A schematic conceptual model of the Dubti hydrothermal area, as derived from reservoir engineering studies integrated with geological

  6. Modeling research in low-medium temperature geothermal field, Tianjin

    Institute of Scientific and Technical Information of China (English)

    王坤; 李春华

    2002-01-01

    The geothermal reservoir in Tianjin can be divided into two parts: the upper one is the porous medium reservoir in the Tertiary system; the lower one includes the basement reservoir in Lower Paleozoic and Middle-Upper Proterozoic. Hot springs are exposed in the northern mountain and confined geothermal water is imbedded in the southern plain. The geothermal reservoir is incised by several fractures. In recent years, TDS of the geothermal water have gone up along with the production rate increasing, along the eastern fracture zone (Cangdong Fracture and West Baitangkou Fracture). This means that the northern fracture system is the main seepage channel of the deep circulation geothermal water, and the reservoir has good connection in a certain area and definite direction. The isotopic research about hydrogen and carbon chronology indicates that the main recharge period of geothermal water is the Holocene Epoch, the pluvial and chilly period of 20 kaBP. The karst conduits in weathered carbonate rocks of the Proterozoic and Lower Paleozoic and the northeast regional fracture system are the main feeding channels of Tianjin geothermal water. Since the Holocene epoch, the geothermal water stayed at a sealed warm period. The tracer test in WR45 doublet system shows that the tracer test is a very effective measure for understanding the reservoir's transport nature and predicting the cooling time and transport velocity during the reinjection. 3-D numerical simulation shows that if the reinjection well keeps a suitable distance from the production well, reinjection will be a highly effective measure to extract more thermal energy from the rock matrix. The cooling of the production well will not be a problem.

  7. Multidisciplinary exploration of the Tendaho Graben geothermal fields

    Science.gov (United States)

    Armadillo, Egidio; Rizzello, Daniele; Verdoya, Massimo; Pasqua, Claudio; Marini, Luigi; Meqbel, Naser; Stimac, Jim; Kebede, Solomon; Mengiste, Andarge; Hailegiorgis, Getenesch; Abera, Fitsum; Mengesha, Kebede

    2017-04-01

    The NW-SE trending Tendaho Graben is the major extensional feature of the Afar, Ethiopia. Rifting and volcanic activity within the graben occurred mostly between 1.8 and 0.6 Ma, but extended to at least 0.2 Ma. Very recent (0.22- 0.03 Ma) activity is focused along the southern part of the younger and active Manda Hararo Rift, which is included in the north-western part of the graben. Extension gave rise to about 1600 m of vertical displacement (verified by drilling) of the basaltic Afar Stratoid sequence, over a crust with a mean thickness of about 23 km. The infill of graben, overlying the Stratoids, consists of volcanic and sedimentary deposits that have been drilled by six exploratory wells. Within the graben, two main geothermal fields have been explored by intensive geological, geochemical and geophysical surveys over an area that approximately covers a square sector of 40x40 km. Both new and existing data sets have been integrated. The Dubti-Ayrobera system is located along the central axis of the graben. Available data, acquired in the last three decades, comprise more than two thousands gravity and magnetic stations, 229 magnetotelluric stations and structural-geological and geochemical observations. The Alalobeda system is located along the SW flank of the graben, at about 25 km from the Dubti-Ayrobera system and has been very recently studied by means of gravimetric (300 stations), magnetotelluric and TDEM (140 stations) geological and geochemical surveys. The new residual magnetic anomaly map has been used to map the younger normal polarity basalt distribution and infer the location of the unknown main rift axis. The bedrock surface resulting by the 3D inversion of the new residual Bouguer anomaly enlightens the main normal faults hindered by sediments and the secondary structures represented by horsts and grabens. The three-dimensional resistivity models allow mapping the sedimentary infill of the graben, fracture zones in the Afar Stradoids bedrock and

  8. Results of investigations at the Ahuachapan geothermal field, El Salvador

    Energy Technology Data Exchange (ETDEWEB)

    Dennis, B.; Goff, F.; Van Eeckhout, E.; Hanold, B. (comps.)

    1990-04-01

    Well logging operations were performed in eight of the geothermal wells at Ahuachapan. High-temperature downhole instruments, including a temperature/rabbit, caliper, fluid velocity spinner/temperature/pressure (STP), and fluid sampler, were deployed in each well. The caliper tool was used primarily to determine if chemical deposits were present in well casings or liners and to investigate a suspected break in the casing in one well. STP logs were obtained from six of the eight wells at various flow rates ranging from 30 to 80 kg/s. A static STP log was also run with the wells shut-in to provide data to be used in the thermodynamic analysis of several production wells. The geochemical data obtained show a system configuration like that proposed by C. Laky and associates in 1989. Our data indicate recharge to the system from the volcanic highlands south of the field. Additionally, our data indicate encroachment of dilute fluids into deeper production zones because of overproduction. 17 refs., 50 figs., 10 tabs.

  9. Application of ethanol as a geothermal tracer: a field-test in the Los Azufres geothermal field, Michoacan, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Tello Hinojosa, Enrique [Comision Federal de Electricidad, Morelia, Michoacan (Mexico); Pal Verma, Mahendra [Comision Federal de Electricidad, Morelia, Michoacan (Mexico); Suarez Arriaga, Mario C. [Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Michoacan (Mexico); Barrera Conzalez, Victor; Sandoval Medina, Fernando [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)

    2005-12-01

    The thermal decomposition rate of ethanol, rhodamine WT and fluoroscein was determined from laboratory data obtained under conditions of temperature and pressure that simulated a geothermal reservoir. It was found that ethylic alcohol had better thermal stability rhodamine and fluoroscein. Using data obtained from de-ionized water experiments after 168 hours and 200 degree centigrade of temperature, the rhodamine WT and fluoroscein presented a degradation of 99.4% and 99.7%, respectively, while for the ethanol the degradation percentage under the same conditions was only of 44.6%. According to this, ethylic alcohol can be used as a conservative tracer up to about 250 degree centigrade, while rhodamine WT and fluoroscein can be used only at less than 200 degree centigrade, and only where the transit return time is expected to be less than 7 days. Ethanol was used as a conservative tracer in a field test in the southern zone of the Los Azufres geothermal field. The highest concentration was detected in a monitoring well in the steam phase 15 days after the injection, and in the liquid phase, or brine, 34 days after the injection. This suggests that alcohol fractionates preferentially in the steam phase and moves or migrates twice as fast than it does in the liquid phase. The tracer speed can be calculated in 176 m/day in the steam phase and 77.5 m/day in the brine. The ethanol presents good enough characteristics to be used as a tracer in both phases in geothermal environments. [Spanish] Se determino la velocidad de descomposicion termica del etanol, la rodamina y la fluoresceina a partir de datos de laboratorio obtenidos bajo condiciones de presion y de temperatura que simulan las de un yacimiento geotermico. Se encontro que el alcohol etilico presenta una mayor estabilidad termica que la rodamina y la fluoresceina. Empleando los datos obtenidos de experimentos con agua de-ionizada despues de 168 horas y a 200 grados centigrados de temperatura, la rodamina y la

  10. Use of geothermal heat for sugar refining. Final report, October 1, 1976--May 31, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, R.O.

    1977-05-01

    The economic and technical feasibility of applying low grade geothermal heat (less than 300/sup 0/F) in the beet sugar refining industry for both new factory construction and retrofit conversion of existing factories was assessed. The representative Holly Sugar factory at Brawley, California, was utilized as a baseline primarily because of its centralized location with respect to the known and partially developed geothermal anomalies at Brawley, East Mesa, and Heber. Nominal values for the key parameters of the sugar refining process and typical values for the geothermal fluid parameters representative of geothermal resources in areas of existing or potential future sugar factories were defined, promising points of application were identified, and conceptual designs synthesized for introducing the geothermal heat into the process. The design approaches were then quantified with capital, operating and maintenance costs, and comparative economic evaluations were made with other fuels projected to 1995. In parallel with the detailed study of process conversion to geothermal heat, the existing pattern and potential growth of the sugar refining industry was assessed to estimate the potential market for new factory construction at suitable areas, as well as the potential for retrofit conversion of existing factories. The environmental impact of other geothermal application concepts was also assessed, and expected technological or industry/government policy changes which might affect the potential for conversion to geothermal heat were identified and evaluated. Emphasis was placed on achieving results that would stimulate commercial utilization of geothermal heat for beet sugar refining and related processes.

  11. Final Scientific / Technical Report, Geothermal Resource Exploration Program, Truckhaven Area, Imperial County, California

    Energy Technology Data Exchange (ETDEWEB)

    Layman Energy Associates, Inc.

    2006-08-15

    sedimentary section is sand-rich, suggesting good potential for a sediment-hosted geothermal reservoir in porous sands, similar to other fields in the region such as Heber and East Mesa. Sand porosity may remain higher in the eastern portion of the low resistivity zone. This is based on its location hydrologically downstream of the probable area of thermal upwelling, intense fracture development, and associated pore-filling hydrothermal mineral deposition to the west.

  12. EXPLORATION BY MEANS OF GEOPHYSICAL METHODS OF GEOTHERMAL FIELDS AND CASE STUDIES

    Directory of Open Access Journals (Sweden)

    Züheyr KAMACI

    1997-01-01

    Full Text Available Geothermal energy which is one of the reuseable energy resources, can save as much as 77 million barrels of petroleum equivalent annually when used in the production of electricity and heating-environment. Geophysical exploration methods plays in important role in the fields of geothermal exploration, development and observational studies. Thermal and geoelectrical methods are the most effective methods which shows the temperature variation anomalies and mechanical drilling places. But, when the other methods of gravity, magnetic, radiometric, well geophysics and well logs can be used in conjunction with seismic tomography, apart from the mentioned geophysical exploration method, better results could be obtained. From the above mentioned facts various case history reports are given from our country and worldwide to determine geothermal energy resources by using geophysical exploration technique application. From these results of studies a 55 °C hot water artessian aquifer is found in the Uşak-Banaz geothermal field by applying geoelectrical methods.

  13. Fluid flow model of the Cerro Prieto Geothermal Field based on well log interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Halfman, S.E.; Lippmann, M.J.; Zelwe, R.; Howard, J.H.

    1982-08-10

    The subsurface geology of the Cerro Prieto geothermal field was analyzed using geophysical and lithologic logs. The distribution of permeable and relatively impermeable units and the location of faults are shown in a geologic model of the system. By incorporating well completion data and downhole temperature profiles into the geologic model, it was possible to determine the direction of geothermal fluid flow and the role of subsurface geologic features that control this movement.

  14. Field based geothermal exploration: Structural controls in the Tarutung Basin/North Central Sumatra (Indonesia)

    Science.gov (United States)

    Nukman, M.; Moeck, I.

    2012-04-01

    The Tarutung Basin is one of several basins along the prominent Sumatra Fault System (SFS) which represents a dextral strike slip fault zone segmented into individual fault strands. The basins are located at right-stepping transfer. The Tarutung Basin hosts geothermal manifestations such as hot springs and travertines indicating a geothermal system with some decent potential in the subsurface. As part of geothermal exploration, field geology is investigated focusing on how the structural setting controls the thermal manifestation distribution. A complex fault pattern is now newly mapped and evidences sinistral faults striking E-W (Silangkitang), normal faults striking SE-NW at the eastern strand of Tarutung Basin (Sitompul) and normal faults striking NW-SE at the western strand of the basin (Sitaka). These structures form an angle greater than 450 with respect to the current maximum principal stress which is oriented in N-S. Secondary sinistral shear fractures identified as antithetic Riedel shears can be correlated with hot spring locations at Silangkitang, forming an angle of 500 with respect to the current maximum stress. A large angle of normal fault and antithetic Riedel shear trend with respect to the current maximum stress direction indicates that the structures have been rotated. Unidentified dextral strike slip faults might exist at the eastern strand of Tarutung Basin to accommodate the clockwise rotation between the eastern boundary of the basin and the NW-SE striking normal fault of Panabungan. Normal faults striking parallel with the SFS East of the basin are interpreted as dilatational jogs caused by the clockwise rotated block movement with respect to the NW-SE fault trend sinistral shear along ENE-WSW faults. Silicified pryroclastics in association with large discharge at hot springs at these NW-SE striking normal faults support this hypothesis. As proposed by Nivinkovich (1976) and Nishimura (1986) Sumatra has rotated 20° clockwise since the last

  15. Solar-geothermal hybrid system

    Energy Technology Data Exchange (ETDEWEB)

    Lentz, Alvaro; Almanza, Rafael [Instituto de Ingenieria, UNAM, Ciudad Universitaria, Edificio 12, 04510 Mexico DF (Mexico)

    2006-10-15

    The Cerro Prieto Geothermal Power Plant is located in the northwest of Mexico, lat. 32{sup o}39', long. 115{sup o}21' in the northern hemisphere. A solar-geothermal hybrid system is proposed in order to increase the steam flow during the present geothermal cycle, adding a solar field of parabolic trough concentrators. Energy is supplied to the geothermal flow from wells in order to increase the steam generation rate. This configuration will increase the capacity factor of the system by generating additional steam during the peak demand hours. The parabolic trough solar field is evaluated in North-South and East-West orientation collector alignments. A proposal to obtain an increase of 10% in steam flow is evaluated, as the increase in flow is limited by the content of dissolved salts, so as to avoid a liquid phase with high salt concentrations. The size of the parabolic troughs field was obtained. (author)

  16. Energy Optimization Modeling of Geothermal Power Plant (Case Study: Darajat Geothermal Field Unit III)

    Science.gov (United States)

    Sinaga, R. H. M.; Darmanto, P. S.

    2016-09-01

    Darajat unit III geothermal power plant is developed by PT. Chevron Geothermal Indonesia (CGI). The plant capacity is 121 MW and load 110%. The greatest utilization power is consumed by Hot Well Pump (HWP) and Cooling Tower Fan (CTF). Reducing the utility power can be attempted by utilizing the wet bulb temperature fluctuation. In this study, a modelling process is developed by using Engineering Equation Solver (EES) software version 9.430.The possibility of energy saving is indicated by Specific Steam Consumption (SSC) net in relation to wet bulb temperature fluctuation from 9°C up to 20.5°C. Result shows that the existing daily operation reaches its optimum condition. The installation of Variable Frequency Drive (VFD) could be applied to optimize both utility power of HWP and CTF. The highest gain is obtained by VFD HWP installation as much as 0.80% when wet bulb temperature 18.5 °C.

  17. Using micro-seismicity and seismic velocities to map subsurface geologic and hydrologic structure within the Coso geothermal field, California

    Science.gov (United States)

    Kaven, Joern Ole; Hickman, Stephen H.; Davatzes, Nicholas C.

    2012-01-01

    Geothermal reservoirs derive their capacity for fluid and heat transport in large part from faults and fractures. Micro-seismicity generated on such faults and fractures can be used to map larger fault structures as well as secondary fractures that add access to hot rock, fluid storage and recharge capacity necessary to have a sustainable geothermal resource. Additionally, inversion of seismic velocities from micro-seismicity permits imaging of regions subject to the combined effects of fracture density, fluid pressure and steam content, among other factors. We relocate 14 years of seismicity (1996-2009) in the Coso geothermal field using differential travel times and simultaneously invert for seismic velocities to improve our knowledge of the subsurface geologic and hydrologic structure. We utilize over 60,000 micro-seismic events using waveform cross-correlation to augment to expansive catalog of P- and S-wave differential travel times recorded at Coso. We further carry out rigorous uncertainty estimation and find that our results are precise to within 10s of meters of relative location error. We find that relocated micro-seismicity outlines prominent, through-going faults in the reservoir in some cases. We also find that a significant portion of seismicity remains diffuse and does not cluster into more sharply defined major structures. The seismic velocity structure reveals heterogeneous distributions of compressional (Vp) and shear (Vs) wave speed, with Vp generally lower in the main field when compared to the east flank and Vs varying more significantly in the shallow portions of the reservoir. The Vp/Vs ratio appears to outline the two main compartments of the reservoir at depths of -0.5 to 1.5 km (relative to sea-level), with a ridge of relatively high Vp/Vs separating the main field from the east flank. In the deeper portion of the reservoir this ridge is less prominent. Our results indicate that high-precision relocations of micro-seismicity can provide

  18. Mushroom growing project at the Los Humeros, Mexico geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Rangel, M.E.R. [Comision Federal de Electricidad (Mexico)

    1998-12-01

    There are several projects of direct (non-electrical) use of geothermal energy in Mexico. Personnel of the Comision Federal de Electricidad (CFE) have experience in various of these projects, like drying of timber and fruits, space heating, food processing, etc. Taking this in consideration, CFE built the Los Humeros mushroom plant using for heat source the geothermal steam from Well H-1. The main purpose of the project was to take advantage of residual geothermal energy in a food production operation and to develop the appropriate technology. In 1992, existing installations were renovated, preparing appropriate areas for pasteurization, inoculation and production. The mushroom Pleurotus ostreatus var. florida and columbinus was used. A year later, CFE proposed the construction of improved facilities for growing edible mushrooms. New materials and equipment, as well as different operation conditions, were proposed on the basis of the experience gained in the initial project. The construction and renovation activities were completed in 1994.

  19. ANALYSIS OF RECHARGE COOLDOWN AT THE WESTERN BOUNDARY OF CERRO PRIETO I GEOTHERMAL FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, P.; Lam, S.; Hunsbedt, A.; Esquer, C.; Marquez, R.; Hernandez, L. Cobo, J.

    1985-01-22

    Extensive study of the Cerro Prieto geothermal field has provided much geologic and thermodynamic data of its structurally-complex, liquid-dominated reservoir. Several of the studies investigated the resource characteristics of fluid and energy flow. An early report by Mercado (1975) showed that the heat source for the part of the reservoir under development, now called Cerro Prieto I (CPI), originated in the eastern part of the field. Subsequent studies confirmed the flow of hot water from the east. A summary of several experimental and numerical studies of fluid and energy transport in the field was given by Lippmann and Bodvarsson (1983). The hydrogeologic model of Halfman et al. (1982) shows hot-water flow from the east divided into a shallow (alpha) aquifer at about 120Om and a deeper (beta) aquifer at about 170Om depth. A cross section along an east-west direction shows a central upflow to the two aquifers and uncertain geology beyond the western border of the field near well M-9. It also shows a fault dividing the line of border wells at M-29 from the inner wells at M-25 to the east. The hydrogeology of the field was described by Sanchez and de la Pena (1981) as an alluvial unit from the surface to about 700 m over the production zone and a shale-sandstone unit comprising an upper, shallow (alpha) aquifer bounded below by a basement horst overlying a deeper (beta) aquifer. To date, much of the cumulative production at Cerro Prieto I has been from the alpha aquifer. Piezometric level measurements over the first 5 years of operation showed a decline in the western zone beyond the production wells. Over the 10-year period of continuous production, a significant temperature decline has been observed along the westernmost line of wells. Several investigations of the recharge characteristics of the field have been reported. Mercado (1975) and Elders et al. (1984) indicated a flow of cold groundwater from the east. Mercado also noted that cold water was entering

  20. The Momotombo Geothermal Field, Nicaragua: Exploration and development case history study

    Energy Technology Data Exchange (ETDEWEB)

    None

    1982-07-01

    This case history discusses the exploration methods used at the Momotombo Geothermal Field in western Nicaragua, and evaluates their contributions to the development of the geothermal field models. Subsequent reservoir engineering has not been synthesized or evaluated. A geothermal exploration program was started in Nicaragua in 1966 to discover and delineate potential geothermal reservoirs in western Nicaragua. Exploration began at the Momotombo field in 1970 using geological, geochemical, and geophysical methods. A regional study of thermal manifestations was undertaken and the area on the southern flank of Volcan Momotombo was chosen for more detailed investigation. Subsequent exploration by various consultants produced a number of geotechnical reports on the geology, geophysics, and geochemistry of the field as well as describing production well drilling. Geological investigations at Momotombo included photogeology, field mapping, binocular microscope examination of cuttings, and drillhole correlations. Among the geophysical techniques used to investigate the field sub-structure were: Schlumberger and electromagnetic soundings, dipole mapping and audio-magnetotelluric surveys, gravity and magnetic measurements, frequency domain soundings, self-potential surveys, and subsurface temperature determinations. The geochemical program analyzed the thermal fluids of the surface and in the wells. This report presents the description and results of exploration methods used during the investigative stages of the Momotombo Geothermal Field. A conceptual model of the geothermal field was drawn from the information available at each exploration phase. The exploration methods have been evaluated with respect to their contributions to the understanding of the field and their utilization in planning further development. Our principal finding is that data developed at each stage were not sufficiently integrated to guide further work at the field, causing inefficient use of

  1. Two-dimensional inversion of resistivity monitoring data from the Cerro Prieto geothermal field

    Science.gov (United States)

    Goldstein, N. E.; Sasaki, Y.; Wilt, M. J.

    1985-03-01

    Two dimensional iterative, least-squares inversions were performed on dc resistivity data obtained over the geothermal field at five successive times during the 1979-1983 period. The solutions gave the percent change in resistivity within each of 47 rectangular blocks representing the reservoir and recharge regions. The changes are consistent with hydrogeologic and recharge models, on the basis of geophysical well logs, well cuttings, well production, geochemical and reservoir engineering data. The solutions support the model of a reservoir that is recharged mainly by cooler, less saline water, causing changes in both pore fluid resistivity and the extent of boiling near the wells. There may be a component of high-temperature recharge from below and to the east, but flow may be impeded by a two-phase zone. Notwithstanding the various sources of error and uncertainty in the data acquisition and 2-D inversions, repetitive, high precision dc resistivity monitoring seems to be a useful method for assessing reservoir conditions when used in conjunction with production and reservoir engineering data and analysis.

  2. Relation between crustal stress field changes and fluid injection at The Geysers geothermal field, California

    Science.gov (United States)

    Martinez, P.; Bohnhoff, M.; Kwiatek, G.

    2012-12-01

    Studying potential spatial and temporal variations of the crustal stress field caused by massive fluid injection during reservoir stimulation is important towards an improved understanding of induced seismicity in different types of reservoirs. However, an accurate and reliable determination of such stress changes is difficult and requires dense local seismic networks with good azimuthal coverage and low magnitude-detection threshold. The Geysers geothermal field is located close to the San Andreas Fault in California, USA. There, induced seismicity associated with the exploitation of the reservoir has been extensively monitored for more than 30 years. While it is evident that seismicity at The Geyser is related to injection and production operations it is difficult to relate the production parameters from individual wells to the spatial and temporal patterns of the crustal stress field and associated seismicity. Earlier attempts to determine the local stress field in the area (Oppenheimer, 1986, J. G. R., 91) estimated the stress orientation by inverting 210 fault plane solutions. He obtained a result that was very consistent with the regional stress field, which might indicate that the regional tectonic stress field dominates over the stresses induced locally by reservoir treatment. In this study we aim at determining potential spatial and temporal variations of the local stress field orientation at The Geysers geothermal site using first motion polarity data provided by a permanent array of 34 stations from Lawrence Berkeley National Laboratory (LBNL) installed in 2007. The network is composed of 3-component short period sensors located at the surface throughout the geothermal field with a sampling frequency of 500 Hz. To determine the stress field orientation we apply different stress inversion methods including non-linear stress inversion algorithms (Abers and Gephart, 2001, J. G. R., 106) with Bayesian uncertainty assessment and a linear approach (Hardebeck

  3. Origin of rainwater acidity near the Los Azufres geothermal field, Mexico

    Science.gov (United States)

    Verma, M.P.; Quijano, J.L.; Johnson, Chad; Gerardo, J.Y.; Arellano, V.

    2000-01-01

    The chemical and isotopic compositions of rainwater were monitored at Los Azufres geothermal field (88 MWe) and its surroundings during May - September 1995, which is the rainy season. Samples were collected from eight sites: three within the field, three in its surroundings and two sufficiently far from the field such that they have no geothermal input. The concentrations of Cl-, SO42- and NO3- were measured in about 350 samples and found to be generally geothermal wells are in the range -3.4 to 0.0???. The ??34S ranges for the natural and anthropogenic sources for environmental sulfur overlap, making it difficult to differentiate between the contribution of different sources. However, a similarity of values of ??34S at Los Azufres and Morelia (85 km distant) suggest a regional source of sulfate that is not associated with geothermal emissions from Los Azufres. (C) 2000 Published by Elsevier Science Ltd on behalf of CNR.The chemical compositions of rainwater were analyzed at Los Azufres geothermal field in Spain from May-September 1995. The concentrations of Cl-, SO42- and NO3- were measured and found to be generally <5 ppm. Chloride concentrations remained constant with time, but sulfate and nitrate concentrations decreased, suggesting a nearby industrial source. A mixing model for Cl-, SO42-, and ??34S also suggested an industrial source for the rainwater sulfur.

  4. GEOTHERMICS GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>20141588 Guo Shiyan(Green Energy Geothermai Development Co.,SINOPEC,Xianyang 712000,China);Li Xiaojun Reservoir Stratum Characteristics and Geothermal Resources Potential of Rongcheng Uplift Geothermal Field in Baoding,Hebei Province(Chinese Journal of Geology,ISSN0563-5020,CN11-1937/P,48(3),2013,p.922-931,2 illus.,4 tables,10 refs.)Key words:geothermal fields,Hebei Province

  5. Sustainability assessment of geothermal exploitation by numerical modelling: the example of high temperature Mofete geothermal field at Campi Flegrei caldera (Southern Italy)

    Science.gov (United States)

    Carlino, Stefano; Troiano, Antonio; Giulia Di Giuseppe, Maria; Tramelli, Anna; Troise, Claudia; Somma, Renato; De Natale, Giuseppe

    2015-04-01

    The active volcanic area of Campi Flegrei caldera has been the site of many geothermal investigations, since the early XX century. This caldera is characterised by high heat flow, with maximum value > 150 mWm-2, geothermal gradients larger than 200°Ckm-1 and diffuse magmatic gases discharge at the surface. These features encouraged an extensive campaign for geothermal investigation, started in 1939, with many drillings performed at Campanian volcanoes (Campi Flegrei and Ischia) and later at Vesuvius. Several wells aimed to the exploitation of high enthalpy geothermal energy, were drilled in the Campi Flegrei caldera, down to a maximum depth of ~3 km involving mainly two sites (Mofete and S.Vito geothermal fields) located in western and northern sector of caldera respectively. The most interesting site for geothermal exploitation was the Mofete zone, where a number of 4 productive wells were drilled and tested to produce electrical power. Based on data inferred from the productive tests it was established a potential electrical extractable power from Mofete field of at least 10MWe. More recently an empirical evaluation of the whole geothermal potential of the caldera provides a value of more than 1 GWe. The results of AGIP-ENEL exploration at Campi Flegrei highlighted the feasibility of geothermal exploitation. Here, we show for the first time the results of numerical simulations (TOUGH2 code ®) of fluids extraction and reinjection from the Mofete geothermal field, in order to produce at least 5MWe from zero emission power plant (Organic Rankine Cycle type). The simulation is aimed to understand the perturbation of the geothermal reservoir in terms of temperature, pressure change, and possible related seismicity, after different simulated time of exploitation. The modeling is mainly constrained by the data derived from geothermal exploration and productive tests performed since 1979 by AGIP-ENEL Companies. A general assessment of the maximum potential magnitude

  6. Assessment on Geothermal Energy Resources and Geothermal Water Storage in Xiaotangshan Geothermal Field%北京小汤山地热田地热资源量及地热水储存量计算与评价

    Institute of Scientific and Technical Information of China (English)

    何铁柱

    2012-01-01

    In this paper, the history of the exploration and utilization of geothermal fields in Xiaotangshan has been described briefly. Also it represents the geological and the geothermal conditions of the geothermal field. Through studying the relevant parameters of the geothermal wells, the Xiaotangshan geothermal field can be divided into two partitions; then, by the thermal reservoir method, the basis of the amount of resources, the geothermal resources, and the heat storage of the geothermal water are estimated as 1746.03×10^12kcal,1290×10^12keal and 25.43×108m^3 respectively.%文章简述了小汤山地热田的开发利用历史,描述了该地热田的地质、地热地质条件。对地热井的有关参数进行了统计分析,将热田分为两个分区,采用热储法计算出基础资源量、地热资源量和地热水的静储量分别为1746.03×10^12kcal、1290×10^12keal和25.43×108m^3。

  7. Numerical simulations of passing seismic waves at the Larderello-Travale Geothermal Field, Italy

    Science.gov (United States)

    Lupi, Matteo; Fuchs, Florian; Saenger, Erik H.

    2017-06-01

    Passing seismic waves released by large-magnitude earthquakes may affect geological systems located thousands of miles far from the epicenter. The M9.0 Tohoku earthquake struck on 11 March 2011 in Japan. We detected local seismic activity at the Larderello-Travale geothermal field, Italy, coinciding with the maximum amplitudes of the Rayleigh waves generated by the Tohoku earthquake. We suggest that the earthquakes were triggered by passing Rayleigh waves that induced locally a maximum vertical displacement of approximately 7.5 mm (for waves with period of 100 s). The estimated dynamic stress was about 8 kPa for a measured peak ground velocity of 0.8 mm/s. Previous similar observations pointed out local seismicity at the Larderello-Travale Geothermal Field triggered by the 2012 Mw5.9 Po Plain earthquake. We conducted forward numerical modeling to investigate the effects caused by passing P, S, Love, and Rayleigh waves through the known velocity structure of the geothermal field. Results indicate that maximum displacements focus differently when considering body or surface waves, with displacement values being higher within the first 2 km of depth. The focusing of the displacement below 3 km seems to be strongly controlled by the velocity structure of the Larderello-Travale geothermal field. We propose that seismic activity triggered by passing seismic waves may be related to a clock-advancing mechanism for local seismic events that may have occurred in any case. Furthermore, our analysis shows that local anisotropies in the velocity structure of the Larderello-Travale geothermal field (possibly linked to compartments of elevated pore pressures) strongly control the reactivation of regions of the geothermal field affected by passing seismic waves.

  8. The Krafla Geothermal Field, Iceland: 3. The Generating Capacity of the Field

    Science.gov (United States)

    Bodvarsson, G. S.; Pruess, K.; Stefansson, V.; Eliasson, E. T.

    1984-11-01

    This paper presents analytical and numerical studies of the generating capacity of the Krafla field. A general lumped parameter model is developed which can be used to obtain rough estimates of the generating capacity of a geothermal field based on the size of the wellfield, the average formation porosity, and the amount of recharge to the system. The model is applied to the old wellfield at Krafla. More sophisticated calculations of the generating capacity of the Krafla field are also performed using distributed-parameter models. Two-dimensional areal models of the various reservoir regions at Krafla are developed and their generating capacities (MWe) evaluated. The results obtained indicate that the old wellfield can sustain steam production of 30 MWe for 30 years. The estimated power potential of the new wellfield is 20 MWe for 30 years. To obtain the required steam production several additional wells may be drilled in the old and new wellfields.

  9. Corrosion studies in brines of the Salton Sea Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Carter, J.P.; McCawley, F.X.; Cramer, S.D.; Needham, P.B. Jr.

    1979-01-01

    Toward the goal of maximizing minerals and metals recovery from domestic resources, the Bureau of Mines, U.S. Department of the Interior, has conducted in situ corrosion studies at the Salton Sea Known Geothermal Resources Area (KGRA) in the Imperial Valley, Calif., to evaluate and characterize materials of construction for geothermal resources recovery plants. General-, pitting, and crevice-corrosion characteristics of 13 commercially available alloys were investigated for periods of 15 and 30 days in seven process environments expected to be found in typical geothermal resources plants. Stainless steel alloy 29-4, Inconel 625, and the Hastelloys G, S, and C-276 were the most resistant to general corrosion, did not pit, and exhibited little susceptibility to crevice corrosion. Stainless steel alloys 430, E-Brite 26-1, and 6X had low general corrosion rates, but pitted and were susceptible to crevice corrosion. Stainless steel alloy 316 L had a low corrosion rate, but corroded intergranularly, pitted, and was susceptible to crevice corrosion and to stress-corrosion cracking. Titanium--1.5 nickel and TiCode-12 had low corrosion rates, did not pit, and were not susceptible to crevice corrosion. Carbon and 4130 steels had high corrosion rates, pitted, and had high susceptibilities to crevice corrosion. The major scale-forming mineral on the corrosion samples in most of the process environments studied was galena mixed with lesser amounts of other minerals.

  10. Tough2/PC application simulation project for Heber geothermal field, California, a progress report

    Energy Technology Data Exchange (ETDEWEB)

    Boardman, Timothy S.; Khan, M. Ali; Antunez, Emilio

    1996-01-24

    A numerical simulation model for the Heber geothermal field in Southern California is being developed under a technology transfer agreement between the Department of Energy/Lawrence Berkeley National Laboratory (LBNL) and the California Department of Conservation, Division of Oil, Gas, and Geothermal Resources (DOGGR). The main objectives of the cooperation are (1) to train DOGGR personnel in the use of the TOUGH2PC computer code; and (2) to develop a module compatible with TOUGH2 to investigate the effects of production/injection operations on the ground surface subsidence-rebound phenomenon observed in the Heber geothermal field. Initial-state calibration (undisturbed system) runs are being conducted to calibrate the model.

  11. Chemical Variations in the Rocks of La Primavera Geothermal Field (Mexico) Related with Hydrothermal Alteration

    Energy Technology Data Exchange (ETDEWEB)

    Prol-Ledesma, R.M.; Hernandez-Lombardini, S.I.; Lozano-Santa Cruz, R.

    1995-01-01

    The origin and fate of the components dissolved in the geothermal fluids are of great importance in the study of epithermal deposits, and in the environmental considerations for exploitation of geothermal fields. The chemical study of La Primavera geothermal field in Mexico has environmental importance due to the high arsenic concentration observed in the thermal water and the possible contamination of aquifers in the area. The variations in the chemistry of all altered samples with respect to unaltered samples indicates depletion of manganese, and the alkalis; and enrichment in iron and magnesium. Most samples show an enrichment in aluminum and titanium, and depletion in silica and calcium. Trace elements follow different trends at various depths: shallow depths are more favorable for deposition of the analyzed trace elements than the surface or the deep part of the reservoir.

  12. Anthropogenic seismicity rates and operational parameters at the Salton Sea Geothermal Field.

    Science.gov (United States)

    Brodsky, Emily E; Lajoie, Lia J

    2013-08-01

    Geothermal power is a growing energy source; however, efforts to increase production are tempered by concern over induced earthquakes. Although increased seismicity commonly accompanies geothermal production, induced earthquake rate cannot currently be forecast on the basis of fluid injection volumes or any other operational parameters. We show that at the Salton Sea Geothermal Field, the total volume of fluid extracted or injected tracks the long-term evolution of seismicity. After correcting for the aftershock rate, the net fluid volume (extracted-injected) provides the best correlation with seismicity in recent years. We model the background earthquake rate with a linear combination of injection and net production rates that allows us to track the secular development of the field as the number of earthquakes per fluid volume injected decreases over time.

  13. SELF-POTENTIAL SURVEY AT THE CERRO PRIETO GEOTHERMAL FIELD, BAJA CALIFORNIA, MEXICO

    Energy Technology Data Exchange (ETDEWEB)

    Corwin, R.F.; Diaz C., S.; Rodriguez B., J.

    1978-06-01

    In December 1977, two self-potential survey lines were run across the producing area of the Cerro Prieto geothermal field, located about 30 km south of Mexicali, Baja California, Mexico. The purpose of the survey was to determine whether significant self-potential variations were related to the known geothermal activity. Large-amplitude, long-wavelength self-potential anomalies are seen in the Cerro Prieto geothermal field. The inflection points of the anomalies are roughly centered over two major faults thought to act as conduits for the thermal fluids, and the form of the anomalies indicates that they may be generated by electrical activity extending to a depth of several km along the fault zones. Thus, self-potential measurements may be helpful in tracing thermally active fault zones in the Cerro Prieto area.

  14. Integrated Resistivity and Ground Penetrating Radar Observations of Underground Seepage of Hot Water at Blawan-Ijen Geothermal Field

    OpenAIRE

    Sukir Maryanto; Ika Karlina Laila Nur Suciningtyas; Cinantya Nirmala Dewi; Arief Rachmansyah

    2016-01-01

    Geothermal resource investigation was accomplished for Blawan-Ijen geothermal system. Blawan geothermal field which located in the northern part of Ijen caldera presents hydrothermal activity related with Pedati fault and local graben. There were about 21 hot springs manifestations in Blawan-Ijen area with calculated temperature about 50°C. We have performed several geophysical studies of underground seepage of hot water characterization. The geoelectric resistivity and GPR methods are used i...

  15. Thermal modeling of step-out targets at the Soda Lake geothermal field, Churchill County, Nevada

    Science.gov (United States)

    Dingwall, Ryan Kenneth

    Temperature data at the Soda Lake geothermal field in the southeastern Carson Sink, Nevada, highlight an intense thermal anomaly. The geothermal field produces roughly 11 MWe from two power producing facilities which are rated to 23 MWe. The low output is attributed to the inability to locate and produce sufficient volumes of fluid at adequate temperature. Additionally, the current producing area has experienced declining production temperatures over its 40 year history. Two step-out targets adjacent to the main field have been identified that have the potential to increase production and extend the life of the field. Though shallow temperatures in the two subsidiary areas are significantly less than those found within the main anomaly, measurements in deeper wells (>1,000 m) show that temperatures viable for utilization are present. High-pass filtering of the available complete Bouguer gravity data indicates that geothermal flow is present within the shallow sediments of the two subsidiary areas. Significant faulting is observed in the seismic data in both of the subsidiary areas. These structures are highlighted in the seismic similarity attribute calculated as part of this study. One possible conceptual model for the geothermal system(s) at the step-out targets indicated upflow along these faults from depth. In order to test this hypothesis, three-dimensional computer models were constructed in order to observe the temperatures that would result from geothermal flow along the observed fault planes. Results indicate that the observed faults are viable hosts for the geothermal system(s) in the step-out areas. Subsequently, these faults are proposed as targets for future exploration focus and step-out drilling.

  16. Hyperspectral Thermal Infrared Analysis of the Salton Sea, CA Geothermal Field

    Science.gov (United States)

    Reath, K. A.; Ramsey, M. S.

    2011-12-01

    The Salton Sea Geothermal Field is an active 20 km2 region in southern California, which lies along the Calipatria Fault; an offshoot of the San Andreas Fault. Several geothermal fields (including the Davis-Schrimpf and Sandbar fields) and ten power plants generating 340 MW lie within this region. In order to better understand the mineral and thermal distribution of the surface, hyperspectral thermal infrared (TIR) data were acquired by Aerospace Corporation using the Spatially Enhanced Broadband Array Spectrograph System (SEABSS) airborne sensor on March 26, 2009 and April 6, 2010. SEBASS collects 128 wavelength channels at 1 meter spatial resolution, from which a new and more accurate interpretation was produced of the surface mineralogy of the geothermal fields and surrounding areas. Such data are rarely available for this type of scientific analysis and enabled the identification of mineral assemblages associated with geothermally-active areas. These minerals include anhydrite, gypsum, as well as an unknown mineral with a unique TIR wavelength feature at 8.2 μm. Comparing the 2009 and 2010 data, this unknown mineral varies in abundance and spatial distribution likely due to changes in rainfall. Samples rich in this mineral were collected from an area identified in the SEBASS data and analyzed in the laboratory using high resolution TIR emission spectroscopy. The same spectral absorption feature was found confirming the mineral's presence. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were performed on one of the samples in order to positively identify this mineral and further constrain the TIR analysis. By using the combination of airborne and laboratory spectroscopy, detailed and temporally-variable patterns of the surface mineralogy were ultimately produced. This work has the potential to be used at other geothermal sites to better characterize transient mineralogy, understand the influence of surface and ground water in these systems, and

  17. Magnetotelluric Study on the Donan Geothermal Field, Southern Part of Hokkaido, Japan

    Science.gov (United States)

    Hayakawa, M.; Mogi, T.

    2016-12-01

    We performed a MT study in the Donan geothermal field where deep seated hot granitic rocks are distributing as a source of geothermal resources. But no prominent fracture zone were found in this area. Imaging a fracture zone and clarifying geothermal reservoirs are purpose of the study. Quaternary volcanoes, such as Hokkaido Komagatake and Esan in the southern part, and Karibayama in the northern part, are situated in the surroundings of the Donan area, southwestern Hokkaido, Japan. Even though recent volcanic activity is not seen in the central part, geothermal gradient is high. The geological structure of this region is dominated by the movement of basement blocks aligning in the north-south, and folds and fractures have developed. Many hot springs and geothermal manifestations are seen in this region where called "Yakumo-Nigorikawa geothermal zone." The Mori geothermal power plant, located at south area, is operating in the Nigorikawa caldera formed about 12,000 years ago. Like Nigorikawa, the Yakumo area, located at the central part of the Donan area, have been thought as promising geothermal area, and many geothermal study were performed in the 1990th. Six drilling holes were excavated and they showed that hot granitic rock are distributing at around below 1000m depth, and temperature is higher than 200 degrees in this area. We carried out new magnetotelluric (MT) survey at 20 stations in the Yakumo area. We constructed 2-D and 3-D resistivity model with MT data. Because the anomalous phases exceeding 90 degree were seen in some sites at frequency less than 0.1Hz, we only used the data at frequency range of 320Hz and 0.1Hz in this study. We used Ogawa and Uchida (1996) as a 2D inversion and Han et al. (2008) that have applied approximate sensitivity, as 3D inversion respectively. From the resistivity models, the remarkable low resistivity zone extending from deep to shallower is seen at the center of the survey area, that is inclined from south to north. A

  18. The nature of magmatism at Palinpinon geothermal field, Negros Island, Philippines: implications for geothermal activity and regional tectonics

    Science.gov (United States)

    Rae, Andrew J.; Cooke, David R.; Phillips, David; Zaide-Delfin, Maribel

    2004-01-01

    The Palinpinon geothermal field, Negros Island, Philippines is a high-temperature, liquid-dominated geothermal system in an active island-arc volcanic setting. This paper presents a regional context for the Palinpinon geology, discusses the petrogenetic evolution of magmatism in the district and assesses the genetic relationships between intrusion and geothermal circulation. The oldest rock formation, the Lower Puhagan Volcanic Formation (Middle Miocene), is part of a volcanic sequence that is traceable throughout the Visayas region and is related to subduction of the Sulu Sea oceanic basin in a southeasterly direction beneath the Sulu arc. Late Miocene to Early Pliocene times mark a period of regional subsidence and marine sedimentation. A thick sequence of calcareous sediments (Okoy Formation) was deposited during this period. Magmatism in Early Pliocene to Recent times coincided with commencement of subduction at the Negros-Sulu Arc. This produced basaltic andesites and andesites belonging to the Southern Negros and Cuernos Volcanic Formations. During this time the Puhagan dikes and the Nasuji Pluton intruded Middle Miocene, Late Miocene and Early-Late Pliocene formations. Based on radiogenic ( 40Ar/ 39Ar) dating of hornblende, the Puhagan dikes are 4.1-4.2 Ma and the Nasuji Pluton 0.3-0.7 Ma. This age difference confirms these intrusions are not genetically related. The Early Pliocene age of the Puhagan dikes also confirms they are not the heat source for the current geothermal system and that a much younger intrusion is situated beyond drill depths. Igneous rock formations in southern Negros are the products of regional island-arc magmatism with medium K, calc-alkaline, basaltic to dacitic compositions. Their adakitic affinity implies that the melting of subducted oceanic basalt has influenced magmatism in this region. Considering the regional tectonic history the most likely scenarios for the generation of slab melts are: (1) during the Middle Miocene, by the

  19. GEOTHERMICS GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>20131088 Fan Difu (Geological Survey of Jiangsu Province , Nanjing 210018 , China ); Xu Xueqiu Origin Study of Geothermal Field in Xiaoyangkou of Rudong County in Jiangsu (Journal of Geology , ISSN1674-3636 , CN32-1796/P , 36 (2), 2012 , p.192-197 , 3illus. , 9refs.) Key words : geothermal fields , Jiangsu Province

  20. Prospects of development of highly mineralized high-temperature resources of the Tarumovskoye geothermal field

    Science.gov (United States)

    Alkhasov, A. B.; Alkhasova, D. A.; Ramazanov, A. Sh.; Kasparova, M. A.

    2016-06-01

    The promising nature of integrated processing of high-temperature geothermal brines of the Tarumovskoye geothermal field is shown. Thermal energy of a geothermal brine can be converted to the electric power at a binary geothermal power plant (GPP) based on low-boiling working substance. The thermodynamic Rankine cycles are considered which are implemented in the GPP secondary loop at different evaporation temperatures of the working substance―isobutane. Among them, the most efficient cycle from the standpoint of attaining a maximum power is the supercritical one which is close to the so-called triangular cycle with an evaporation pressure of p e = 5.0 MPa. The used low-temperature brine is supplied from the GPP to a chemical plant, where main chemical components (lithium carbonate, burnt magnesia, calcium carbonate, and sodium chloride) are extracted from it according to the developed technology of comprehensive utilization of geothermal brines of chloride-sodium type. The waste water is delivered to the geotechnological complex and other consumers. For producing valuable inorganic materials, the electric power generated at the GPP is used. Owing to this, the total self-sufficiency of production and independence from external conditions is achieved. The advantages of the proposed geotechnological complex are the full utilization of the heat potential and the extraction of main chemical components of multiparameter geothermal resources. In this case, there is no need for reverse pumping, which eliminates the significant capital costs for building injection wells and a pumping station and the operating costs for their service. A characteristic of the modern state of the field and estimated figures of the integrated processing of high-temperature brines of well no. 6 are given, from which it follows that the proposed technology has a high efficiency. The comprehensive development of the field resources will make it possible to improve the economic structure of the

  1. Measured ground-surface movements, Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Massey, B.L.

    1981-01-01

    The Cerro Prieto geothermal area in the Mexicali Valley, 30 kilometers southeast of Mexicali, Baja California, incurred slight deformation because of the extraction of hot water and steam, and probably, active tectonism. During 1977 to 1978, the US Geological Survey established and measured two networks of horizontal control in an effort to define both types of movement. These networks consisted of: (1) a regional trilateration net brought into the mountain ranges west of the geothermal area from stations on an existing US Geological Survey crustal-strain network north of the international border; and (2) a local net tied to stations in the regional net and encompassing the present and planned geothermal production area. Electronic distance measuring instruments were used to measure the distances between stations in both networks in 1978, 1979 and 1981. Lines in the regional net averaged 25 km. in length and the standard deviation of an individual measurement is estimated to be approx. 0.3 part per million of line length. The local network was measured using different instrumentation and techniques. The average line length was about 5 km. and the standard deviation of an individual measurement approached 3 parts per million per line length. Ground-surface movements in the regional net, as measured by both the 1979 and 1981 resurveys, were small and did not exceed the noise level. The 1979 resurvey of the local net showed an apparent movement of 2 to 3 centimeters inward toward the center of the production area. This apparent movement was restricted to the general limits of the production area. The 1981 resurvey of the local net did not show increased movement attributable to fluid extraction.

  2. Light hydrocarbons as redox and temperature indicators in the geothermal field of El Tatio (northern Chile)

    Energy Technology Data Exchange (ETDEWEB)

    Tassi, F. [University of Florence (Italy). Dept. of Earth Sciences; Martinez, C. [University Catolica del Norte, Antofagasta (Chile). Dept. of Earth Science; Vaselli, O. [University of Florence (Italy). Dept. of Earth Sciences; Institute of Geosciences and Earth Resources, Florence (Italy). National Council of Research; Capaccioni, B. [University of Urbino (Italy). Institute of Volcanology and Geochemistry; Viramonte, J. [National University of Salta (Argentina). Institute GEONORTE and CONICET

    2005-11-15

    El Tatio (northern Chile), one of the largest geothermal fields of South America, is presently undergoing a new program of geothermal exploration, after the failure of the first exploration phase in the early 1970s. The geochemical features of the fluid discharges characterizing this system mainly consist of boiling pools and fumaroles, and represent the result of a complex mixing process involving 3 main components: (i) hydrothermal; (ii) atmospheric; (iii) magmatic. Chemical reactions involving light hydrocarbons equilibrate at higher temperature than those directly measured in the geothermal wells and calculated on the basis of the composition of the inorganic gas species. This suggests that in the deeper parts of the hydrothermal system temperatures higher than 300{sup o}C may be achieved. Such results can have a strong impact for the evaluation of the potential resources of this geothermal system. Moreover, the chemical characteristics of the organic gas fraction allow the assessment of the chemical-physical conditions governing the geochemical processes acting on geothermal fluids at depth. (author)

  3. Use of slim holes for reservoir evaluation at the Steamboat Hills Geothermal Field, Nevada, USA

    Energy Technology Data Exchange (ETDEWEB)

    Combs, Jim; Goranson, Colin

    1994-01-20

    Three slim holes were drilled at the Steamboat Hills Geothermal Field in northwestern Nevada about 15 km south of Reno. The slim holes were drilled to investigate the geologic conditions, thermal regime and productive characteristics of the geothermal system. They were completed through a geologic sequence consisting of alluvium cemented by geothermal fluids, volcaniclastic materials, and granodiorite. Numerous fractures, mostly sealed, were encountered throughout the drilled depth; however, several open fractures in the granodiorite, dipping between 65 and 90{degree}, had apertures up to 13 mm in width. The depths of the slim holes vary from 262 to 277 m with open-hole diameters of 76 mm. Pressure and temperature logs gave bottom-hole temperatures ranging from 163 to 166{degree} C. During injection testing, downhole pressures were measured using capillary tubing with a surface quartz transducer while temperatures were measured with a Kuster temperature tool located below the capillary tubing pressure chamber. No pressure increase was measured at reservoir depths in any of the three slim holes while injecting 11 kg/s of 29{degree}C water indicating a very high permeability in the geothermal reservoir. These injection test results suggested that productive geothermal fluids could be found at depths sufficient for well pumping equipment and at temperatures needed for electrical power production using binary-type conversion technology.

  4. Long-term Evolution of Seismicity Rates in California Geothermal Fields

    Science.gov (United States)

    Trugman, D. T.; Shearer, P. M.; Borsa, A. A.; Fialko, Y. A.

    2015-12-01

    The temporal evolution of seismicity rates within geothermal fields provides important observational constraints on the ways in which rocks respond to natural and anthropogenic loading. We develop an iterative, regularized inversion procedure to partition the observed seismicity rate into two primary components: (1) the interaction seismicity rate due to earthquake-earthquake triggering, and (2) the time-varying background seismicity rate controlled by other time-dependent stresses, including anthropogenic forcing. We parameterize our seismicity model using an Epidemic-Type Aftershock Sequence (ETAS) framework with a background seismicity rate that varies smoothly with time. We apply our methodology to study long-term changes in seismicity rates at the Geysers and Salton Sea geothermal fields in California. At the Geysers, we find that the background seismicity rate is highly correlated with fluid injection. Seismicity at the Geysers has experienced a rate increase of approximately 50% since year 2000 and exhibits strong seasonal fluctuations, both of which can be explained by changes in fluid injection following the completion of the Santa Rosa pipeline. At the Salton Sea, the background seismicity rate has remained relatively stable since 1990, with short-term fluctuations that are not obviously modulated by fluid fluxes related to the operation of the geothermal field. The differences in the field-wide seismicity responses of the Geysers and Salton Sea to geothermal plant operation may reflect differences in in-situ reservoir conditions and local tectonics, indicating that induced seismicity may not be solely a function of fluid injection and withdrawal.

  5. Workshop on CSDP data needs for the BACA geothermal field: a summary

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, D.C.; Tsang, C.F. (eds.)

    1984-06-01

    These workshop summaries discuss the data needs of the Continental Scientific Drilling Program (CSDP) community and provide an introduction to the available geological, geophysical, geochemical and reservoir engineering data of the Baca geothermal field, Valles Caldera, New Mexico. Individual abstracts have been prepared for the presentations. (ACR)

  6. Attenuation tomography using microearthquake (MEQ) data in the "A" geothermal field

    Science.gov (United States)

    Hasanah, Mia Uswatun; Nugraha, Andri Dian; Sule, Rachmat

    2013-09-01

    Attenuation is a physical parameter of rock that can reflect the geological conditions beneath the earth's surface. We conducted attenuation tomographic imaging in the "A" geothermal field by using microearthquake (MEQ) data. We applied a method of spectral fitting to invert the t* value. For the attenuation tomographic inversion, we used the initial 3-D velocity model from the previous study in the region. Our study shows that the value of Qp, Qs and Qp/Qs ratio in the geothermal field is an important parameter for interpreting the subsurface structure. The "A" geothermal field in this study lies between several active and dormant volcanoes in West Java Province, Indonesia. This geothermal field already produces electricity of more than 220 MWe. The hydraulic stimulation has been carried out from the end of 2007 until the beginning of 2008. This experiment was carried out in order to get an understanding about the orientation of weak or fractures zones in the subsurface, so that the strategy of future exploration and well targeting could be estimated. We interpreted the joint immaging result of Qp, Qs and Qp/Qs ratio with previous seismic velocities (Vp, Vs and Vp/Vs ratio) tomography result. We can see that the high attenuation value (low Q value) and low velocity anomaly structures may associated to fluid filled rock and also fault segment.

  7. Feasibility of Geothermal Energy Extraction from Non-Activated Petroleum Wells in Arun Field

    Science.gov (United States)

    Syarifudin, M.; Octavius, F.; Maurice, K.

    2016-09-01

    The big obstacle to develop geothermal is frequently came from the economical viewpoint which mostly contributed by the drilling cost. However, it potentially be tackled by converting the existing decommissioned petroleum well to be converted for geothermal purposes. In Arun Field, Aceh, there are 188 wells and 62% of them are inactive (2013). The major obstacle is that the outlet water temperature from this conversion setup will not as high as the temperature that come out from the conventional geothermal well, since it will only range from 60 to 180oC depending on several key parameters such as the values of ground temperature, geothermal gradient in current location, the flow inside of the tubes, and type of the tubes (the effect from these parameters are studied). It will just be considered as low to medium temperature, according to geothermal well classification. Several adjustments has to be made such as putting out pipes inside the well that have been used to lift the oil/gas and replacing them with a curly long coil tubing which act as a heat exchanger. It will convert the cold water from the surface to be indirectly heated by the hot rock at the bottom of the well in a closed loop system. In order to make power production, the binary cycle system is used so that the low to medium temperature fluid is able to generate electricity. Based on this study, producing geothermal energy for direct use and electricity generation in Arun Field is technically possible. In this study case, we conclude that 2900 kW of electricity could be generated. While for-direct utility, a lot of local industries in Northern Sumatera could get the benefits from this innovation.

  8. 3-D analysis and interpretation of magnetotelluric data from the Aluto-Langano geothermal field, Ethiopia

    Science.gov (United States)

    Samrock, F.; Kuvshinov, A.; Bakker, J.; Jackson, A.; Fisseha, S.

    2015-09-01

    The Main Ethiopian Rift Valley encompasses a number of volcanoes, which are known to be actively deforming with reoccurring periods of uplift and setting. One of the regions where temporal changes take place is the Aluto volcanic complex. It hosts a productive geothermal field and the only currently operating geothermal power plant of Ethiopia. We carried out magnetotelluric (MT) measurements in early 2012 in order to identify the source of unrest. Broad-band MT data (0.001-1000 s) have been acquired at 46 sites covering the expanse of the Aluto volcanic complex with an average site spacing of 1 km. Based on this MT data it is possible to map the bulk electrical resistivity of the subsurface down to depths of several kilometres. Resistivity is a crucial geophysical parameter in geothermal exploration as hydrothermal and magmatic reservoirs are typically related to low resistive zones, which can be easily sensed by MT. Thus by mapping the electrical conductivity one can identify and analyse geothermal systems with respect to their temperature, extent and potential for production of energy. 3-D inversions of the observed MT data from Aluto reveal the typical electrical conductivity distribution of a high-enthalpy geothermal system, which is mainly governed by the hydrothermal alteration mineralogy. The recovered 3-D conductivity models provide no evidence for an active deep magmatic system under Aluto. Forward modelling of the tippers rather suggest that occurrence of melt is predominantly at lower crustal depths along an off-axis fault zone a few tens of kilometres west of the central rift axis. The absence of an active magmatic system implies that the deforming source is most likely situated within the shallow hydrothermal system of the Aluto-Langano geothermal field.

  9. Geothermal resources characteristics of Shilin basin geothermal field in Yunnan province%云南石林盆地地热田地热资源特征

    Institute of Scientific and Technical Information of China (English)

    姚明波; 刘红战; 陈康

    2013-01-01

    石林是国家地质公园,位于滇东断陷盆地,其地热研究是对云南断陷盆地地热研究的理论论证.论文通过对石林地热的热源、热田结构、水文地质特征、水化学特征进行研究,地热类型为深循环层状地热田,受九乡-石垭口断裂和牛头山古陆控制,形成封闭的层状低温地热田.从水文地质条件看,地下热水水化学类型为HCO3-Ca,偏硅酸含量较高.地热热储层埋藏深,水温45 ~51℃,地下热水具承压性,宜于开采利用.但热田水补给资源有限,且上部冷水丰富,应控制地热水的开发利用.该研究成果对滇东其他岩溶断陷盆地地热开发有应用和参考价值.%Shilin is a national geological park which is located in eastern Yunnan basin.The study on its geothermal is the theoretical demonstration of Yunnan rift basin geothermal.This paper studied the geothermal type,geothermal field structure,hydrogeological characteristics and water chemistry characteristics.The geothermal type belongs to deep cycle layered geothermal field and controlled by Jiyxiang-Shiyakou fault and Niutoushan ancient land so as to form the low temperature geothermal field of close layered.According to the hydrogeological conditions,the chemical type of geothermal water is HCO3-Ca with high silicic acid content.As the geothermal reservoir is deeply buried,its water temperature is from 45 to 51 centigrade and with pressure-bearing,the underground hot water is suitable to exploit.While the resources supply is limited and the upper cold water is rich,the development and utilization of geothermal water should be controled.The result has application and reference value for the development of other eastern Yunnan karst rift basins.

  10. Geothermal power plants of the United States: a technical survey of existing and planned installations

    Energy Technology Data Exchange (ETDEWEB)

    DiPippo, R.

    1978-04-01

    The development of geothermal energy as a source of electric power in the United States is reviewed. A thorough description is given of The Geysers geothermal power project in northern California. The recent efforts to exploit the hot-water resources of the Mexicali-Imperial Rift Valley are described. Details are given concerning the geology of the several sites now being used and for those at which power plants will soon be built. Attention is paid to the technical particulars of all existing plants, including wells, gathering systems, energy conversion devices, materials, environmental impacts, economics and operating characteristics. Specifically, plants which either exist or are planned for the following locations are covered: The Geysers, CA; East Mesa, CA; Heber, CA; Roosevelt Hot Springs, UT; Valles Caldera, NM; Salton Sea, CA; Westmorland, CA; Brawley, CA; Desert Peak, NV; and Raft River, ID. The growth of installed geothermal electric generating capacity is traced from the beginning in 1960 and is projected to 1984.

  11. Laboratory study of acid stimulation of drilling-mud-damaged geothermal-reservoir materials. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1983-05-01

    Presented here are the results of laboratory testing performed to provide site specific information in support of geothermal reservoir acidizing programs. The testing program included laboratory tests performed to determine the effectiveness of acid treatments in restoring permeability of geologic materials infiltrated with hydrothermally altered sepiolite drilling mud. Additionally, autoclave tests were performed to determine the degree of hydrothermal alteration and effects of acid digestion on drilling muds and drill cuttings from two KGRA's. Four laboratory scale permeability/acidizing tests were conducted on specimens prepared from drill cuttings taken from two geothermal formations. Two tests were performed on material from the East Mesa KGRA Well No. 78-30, from a depth of approximately 5500 feet, and two tests were performed on material from the Roosevelt KGRA Well No. 52-21, from depths of approximately 7000 to 7500 feet. Tests were performed at simulated in situ geothermal conditions of temperature and pressure.

  12. Elevated carbon dioxide flux at the Dixie Valley geothermal field, Nevada; relations between surface phenomena and the geothermal reservoir

    Science.gov (United States)

    Bergfeld, D.; Goff, F.; Janik, C.J.

    2001-01-01

    In the later part of the 1990s, a large die-off of desert shrubs occurred over an approximately 1 km2 area in the northwestern section of the Dixie Valley (DV) geothermal field. This paper reports results from accumulation-chamber measurements of soil CO2 flux from locations in the dead zone and stable isotope and chemical data on fluids from fumaroles, shallow wells, and geothermal production wells within and adjacent to the dead zone. A cumulative probability plot shows three types of flux sites within the dead zone: Locations with a normal background CO2 flux (7 g m-2 day-1); moderate flux sites displaying "excess" geothermal flux; and high flux sites near young vents and fumaroles. A maximum CO2 flux of 570 g m-2 day-1 was measured at a location adjacent to a fumarole. Using statistical methods appropriate for lognormally distributed populations of data, estimates of the geothermal flux range from 7.5 t day-1 from a 0.14-km2 site near the Stillwater Fault to 0.1 t day-1 from a 0.01 -km2 location of steaming ground on the valley floor. Anomalous CO2 flux is positively correlated with shallow temperature anomalies. The anomalous flux associated with the entire dead zone area declined about 35% over a 6-month period. The decline was most notable at a hot zone located on an alluvial fan and in the SG located on the valley floor. Gas geochemistry indicates that older established fumaroles along the Stillwater Fault and a 2-year-old vent in the lower section of the dead zone discharge a mixture of geothermal gases and air or gases from air-saturated meteoric water (ASMW). Stable isotope data indicate that steam from the smaller fumaroles is produced by ??? 100??C boiling of these mixed fluids and reservoir fluid. Steam from the Senator fumarole (SF) and from shallow wells penetrating the dead zone are probably derived by 140??C to 160??C boiling of reservoir fluid. Carbon-13 isotope data suggest that the reservoir CO2 is produced mainly by thermal decarbonation of

  13. Thermal Modeling of an Area N-W of the Larderello Geothermal Field, Italy.

    Science.gov (United States)

    Bellani, S.; Gherardi, F.

    2008-12-01

    A wide area enclosed between the ancient Etruscan town of Volterra and the northern rim of the Larderello high enthalpy geothermal field (Tuscany, Italy) shows thermal features which suggest further investigations aimed at mid-low enthalpy geothermal energy exploitation. Thermal gradients are in the range 75 - 100 C°/km, while surface heat flow spans between 100 - 150 mW/m2. Numerical simulations were performed to predict the spatial distribution of temperature and fluid circulation paths, constrained by field data. Temperature control based on real data is allowed by a few deep exploratory geothermal wells along with several shallower gradient wells, down to a maximum of about 3 km. The model domain extends over an area 20 by 10 km; thickness is 6 km. Local geology is simplified in four different terrains, according to the generalized stratigraphy of the area. Several sets of simulations were carried out running SHEMAT and TOUGH2 numerical codes, considering various boundary conditions, inner geometries and hydraulic permeabilities. The model was realized by means of unsteady forward simulations, under the assumptions of impervious and isothermal top and bottom boundaries, lateral adiabatic faces and variable internal physical properties. The results indicate that the present temperature and pressure distribution of hot fluids with depth in the northern border area of the Larderello field allows to hypothesize a fruitful exploitation of the medium- enthalpy geothermal resources, possibly with low-boiling point fluids binary plants for electricity generation.

  14. Geothermal energy: opportunities for California commerce. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1982-08-01

    This report provides a preliminary engineering and economic assessment of five direct use projects using low and moderate temperature geothermal resources. Each project site and end-use application was selected because each has a high potential for successful, near-term (2 to 5 years) commercial development. The report also includes an extensive bibliography, and reference and contact lists. The five projects are: Wendel Agricultural Complex, East Mesa Livestock Complex, East Mesa Vegetable Dehydration Facility, Calapatria Heating District and Bridgeport Heating District. The projects involve actual investors, resource owners, and operators with varying financial commitments for project development. For each project, an implementation plan is defined which identifies major barriers to development and methods to overcome them. All projects were determined to be potentially feasible. Three of the projects cascade heat from a small-scale electric generator to direct use applications. Small-scale electric generation technology (especially in the 0.5 to 3 MW range) has recently evolved to such a degree as to warrant serious consideration. These systems provide a year-round heating load and substantially improve the economic feasibility of most direct use energy projects using geothermal resources above 200/sup 0/F.

  15. Abrupt physical and chemical changes during 1992-1999, Anderson Springs, SE Geyser Geothermal Field, California

    Science.gov (United States)

    Janik, Cathy J.; Goff, Fraser; Walter, Stephen R.; Sorey, Michael L.; Counce, Dale; Colvard, Elizabeth M.

    2000-01-01

    of steam discharges from the Southeast Geysers. The hot spring waters are low in ions of Cl, B, and Li, but relatively high in HCO3, SO4 and NH4. The stable-isotope compositions (deuterium and oxygen-18) of these waters plot near the global meteoric water line. Geochemical data through time reveal apparent maxima in the concentrations of SO4, Fe, and Mn in 1991 to 1992, before the cluster became hotter. The black-to-gray deposits from the new spring cluster are rich in pyrite and contain anomalous metals. About one-half mile to the east of the hot springs, mineralized water discharges intermittently from an old adit of the Schwartz (Anderson) mine, and enters a tributary of Anderson Creek. This drainage increased substantially in July 1998, and a slurry of mine water and precipitates were transported down the tributary and into Anderson Creek. In December 1998, the adit water was 22°C, and had a chemical composition that was similar to spring waters that once discharged in the ravines surrounding the old Anderson Springs resort. The cause for the abrupt changes that have occurred in thermal features at Anderson Springs is still not resolved. One possibility is that these changes are a response to withdrawal of steam from The Geysers geothermal field over more than 20 years of production. Pressure declines in the geothermal reservoir may have caused a "drying out" of the overlying condensation zone. Induced boiling in this zone and upflow of deep steam to shallower depths would cause heating and vaporization of shallow ground waters. In addition, earthquakes occurring in the vicinity of Anderson Springs have increased significantly after nearby geothermal power plants began operation. These earthquakes may have enhanced surface discharge of thermal fluids along fractures and faults.

  16. Vitrinite reflectance geothermometry and apparent heating duration in the Cerro Prieto geothermal field

    Science.gov (United States)

    Barker, C.E.; Elders, W.A.

    1981-01-01

    Vitrinite reflectance measured in immersion oil (Ro) on kerogen extracted from hydrothermally altered mudstones in borehole M-84 at the Cerro Prieto geothermal field exhibit an increase in mean reflectance (Ro) from 0.12 per cent at 0.24 km depth to 4.1 per cent at 1.7 km depth. Downhole temperatures measured over this interval increase from about 60?? to 340??C. These Ro data plotted against temperature fall along an exponential curve with a coefficient of determination of about 0.8. Other boreholes sampled in the field show similar relationships. A regression curve calculated for temperature and Ro in borehole M-105 correctly predicts temperatures in other boreholes within the central portion of the geothermal system. The correlation between the reflectance values and logged temperature, together with consistent temperature estimates from fluid inclusion and oxygen isotope geothermometry, indicates that changes in Ro are an accurate and sensitive recorder of the maximum temperature attained. Therefore, vitrinite reflectance can be used in this geothermal system to predict the undisturbed temperature in a geothermal borehole during drilling before it regains thermal equilibrium. Although existing theoretical functions which relate Ro to temperature and duration of heating are inaccurate, empirical temperature-Ro curves are still useful for geothermometry. A comparison of temperature-Ro regression curves derived from nine boreholes within the Cerro Prieto system suggests that heating across the central portion of the field occurred penecontemporaneously, but varies near margins. Boreholes M-93 and M-94 appear to have cooled from their maximum temperatures, whereas M-3 and Prian-1 have only recently been heated. Comparison of the temperature-Ro data from the Salton Sea, California, geothermal system indicates that the duration of heating has been longer there than at the Cerro Prieto field. ?? 1981.

  17. Brine treatment test for reinjection on Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Hurtado, R.; Mercado, S.; Gamino, H. (Departamento de Geotermia, Division de Fuentes de Energia, Instituto de Investigaciones Electricas, Justo Sierra y Herreros Sur 2098-Altos C.P. 21020, Mexicali, B.C. (MX))

    1989-01-01

    Reinjection of disposal brine from the Cerro Prieto Geothermal Power Plant System is attractive mainly because, on top of solving the brine disposal problem, it may significantly contribute to extend the reservoir useful lifetime, through thermal and hydraulic recharge. Because the high concentration of colloidal silica in the disposal brine, laboratory and pilot plant tests were conducted in order to develop the brine treatment process. Addition of 20-40 mg/1 lime to flashed and aged brine for 10-20 minutes yields a clarified brine relatively low in suspended solids (10-30 mg/1) when the over flow rate is 38.5 1/min-m/sup 2/. 1.1 mills/kWh was the estimated cost for treatment of 800 kg/s of separated brine from the Cerro Prieto I power station.

  18. Application of oil-field well log interpretation techniques to the Cerro Prieto Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Ershaghi, I.; Phillips, L.B.; Dougherty, E.L.; Handy, L.L.

    1979-10-01

    An example is presented of the application of oil-field techniques to the Cerro Prieto Field, Mexico. The lithology in this field (sand-shale lithology) is relatively similar to oil-field systems. The study was undertaken as a part of the first series of case studies supported by the Geothermal Log Interpretation Program (GLIP) of the US Department of Energy. The suites of logs for individual wells were far from complete. This was partly because of adverse borehole conditions but mostly because of unavailability of high-temperature tools. The most complete set of logs was a combination of Dual Induction Laterolog, Compensated Formation Density Gamma Ray, Compensated Neutron Log, and Saraband. Temperature data about the wells were sketchy, and the logs had been run under pre-cooled mud condition. A system of interpretation consisting of a combination of graphic and numerical studies was used to study the logs. From graphical studies, evidence of hydrothermal alteration may be established from the trend analysis of SP (self potential) and ILD (deep induction log). Furthermore, the cross plot techniques using data from density and neutron logs may help in establishing compaction as well as rock density profile with depth. In the numerical method, R/sub wa/ values from three different resistivity logs were computed and brought into agreement. From this approach, values of formation temperature and mud filtrate resistivity effective at the time of logging were established.

  19. Inverse modeling and forecasting for the exploitation of the Pauzhetsky geothermal field, Kamchatka, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Finsterle, Stefan; Kiryukhin, A.V.; Asaulova, N.P.; Finsterle, S.

    2008-04-01

    A three-dimensional numerical model of the Pauzhetsky geothermal field has been developed based on a conceptual hydrogeological model of the system. It extends over a 13.6-km2 area and includes three layers: (1) a base layer with inflow; (2) a geothermal reservoir; and (3) an upper layer with discharge and recharge/infiltration areas. Using the computer program iTOUGH2 (Finsterle, 2004), the model is calibrated to a total of 13,675 calibration points, combining natural-state and 1960-2006 exploitation data. The principal model parameters identified and estimated by inverse modeling include the fracture permeability and fracture porosity of the geothermal reservoir, the initial natural upflow rate, the base-layer porosity, and the permeabilities of the infiltration zones. Heat and mass balances derived from the calibrated model helped identify the sources of the geothermal reserves in the field. With the addition of five makeup wells, simulation forecasts for the 2007-2032 period predict a sustainable average steam production of 29 kg/s, which is sufficient to maintain the generation of 6.8 MWe at the Pauzhetsky power plant.

  20. Mapping the Geothermal System Using AMT and MT in the Mapamyum (QP Field, Lake Manasarovar, Southwestern Tibet

    Directory of Open Access Journals (Sweden)

    Lanfang He

    2016-10-01

    Full Text Available Southwestern Tibet plays a crucial role in the protection of the ecological environment and biodiversity of Southern Asia but lacks energy in terms of both power and fuel. The widely distributed geothermal resources in this region could be considered as potential alternative sources of power and heat. However, most of the known geothermal fields in Southwestern Tibet are poorly prospected and currently almost no geothermal energy is exploited. Here we present a case study mapping the Mapamyum (QP geothermal field of Southwestern Tibet using audio magnetotellurics (AMT and magnetotellurics (MT methods. AMT in the frequency range 11.5–11,500 Hz was used to map the upper part of this geothermal reservoir to a depth of 1000 m, and MT in the frequency range 0.001–320 Hz was used to map the heat source, thermal fluid path, and lower part of the geothermal reservoir to a depth greater than 1000 m. Data from 1300 MT and 680 AMT stations were acquired around the geothermal field. Bostick conversion with electromagnetic array profiling (EMAP filtering and nonlinear conjugate gradient inversion (NLCGI was used for data inversion. The AMT and MT results presented here elucidate the geoelectric structure of the QP geothermal field, and provide a background for understanding the reservoir, the thermal fluid path, and the heat source of the geothermal system. We identified a low resistivity anomaly characterized by resistivity in the range of 1–8 Ω∙m at a depth greater than 7 km. This feature was interpreted as a potential reflection of the partially melted magma in the upper crust, which might correlate to mantle upwelling along the Karakorum fault. It is likely that the magma is the heat source of the QP geothermal system, and potentially provides new geophysical evidence to understand the occurrence of the partially melted magmas in the upper crust in Southwestern Tibet.

  1. Did stresses from the Cerro Prieto Geothermal Field influence the El Mayor-Cucapah rupture sequence?

    Science.gov (United States)

    Trugman, Daniel T.; Borsa, Adrian A.; Sandwell, David T.

    2014-12-01

    The Mw 7.2 El Mayor-Cucapah (EMC) earthquake ruptured a complex fault system in northern Baja California that was previously considered inactive. The Cerro Prieto Geothermal Field (CPGF), site of the world's second largest geothermal power plant, is located approximately 15 km to the northeast of the EMC hypocenter. We investigate whether anthropogenic fluid extraction at the CPGF caused a significant perturbation to the stress field in the EMC rupture zone. We use Advanced Land Observing Satellite interferometric synthetic aperture radar data to develop a laterally heterogeneous model of fluid extraction at the CPGF and estimate that this extraction generates positive Coulomb stressing rates of order 15 kPa/yr near the EMC hypocenter, a value which exceeds the local tectonic stressing rate. Although we cannot definitively conclude that production at the CPGF triggered the EMC earthquake, its influence on the local stress field is substantial and should not be neglected in local seismic hazard assessments.

  2. Thermo Hot Springs: MT and Gravity observations of a producing geothermal field in Utah, USA

    Science.gov (United States)

    Hardwick, C.; Chapman, D. S.; Gettings, P.

    2012-12-01

    Thermo Hot Springs, an existing 10 MW geothermal resource in southern Utah, is poorly understood with little constraint on subsurface extent and capacity. In an effort to expand geothermal production, the subsurface extent of the system is being explored by gravity and magnetotelluric (MT) surveys. Since summer of 2010 we have added 108 gravity stations and 90 MT stations in the study area. Complete Bouguer anomaly shows a prominent north-south regional trend of 10 to 15 mGal amplitude which is interpreted as a large Basin-and-Range normal fault. Northeast of the hot springs there is an east-west trending gravity low of 4 mGal amplitude which is interpreted as a fault with down throw to the north. These two trends intersect adjacent to the hot spring, and are interpreted to be the structural control of the fluid flow. Preliminary results from 2-dimensional inversion models of gravity and MT profiles provide depth-to-basement values as shallow as 200 m near the hot spring and as deep as 2 km in the southwest of the study area. We believe that the low resistivities observed in the southwest indicate the existence of hot fluids and/or clay rich sediments at a thickness of more than 1.5 km overlying hot, saturated basement rock. A deep, stratigraphically hosted geothermal system could be present in the southwest and may be connected to the hot springs through a north trending, deeply penetrating fracture zone. With the addition of regional borehole data, thermal gradient wells and water chemistry we aim to constrain the extent of the geothermal system, identify its source and quantify its total production potential.

  3. Structural Controls of Neal Hot Springs Geothermal Field, Malhuer County, Oregon

    Science.gov (United States)

    Edwards, J. H.; Faulds, J. E.

    2012-12-01

    Detailed mapping (1:24,000) of the Neal Hot Springs area (90 km2) in eastern Oregon is part of a larger study of geothermal systems in the Basin and Range, which focuses on the structural controls of geothermal activity. The study area lies within the intersection of two regional grabens, the middle-late Miocene, N-striking, Oregon-Idaho graben and younger late Miocene to Holocene, NW-striking, western Snake River Plain graben. The geothermal field is marked by Neal Hot Springs, which effuse from opaline sinter mounds just north of Bully Creek. Wells producing geothermal fluids, with temperatures at 138°C, intersect a major, W-dipping, NNW-striking, high-angle normal fault at depths of 850-915 m. Displacement along this structure dies southward, with likely horse-tailing, which commonly produces high fracture density and a zone of high permeability conducive for channeling hydrothermal fluids. Mapping reveals that the geothermal resource lies within a local, left step-over. 'Hard-linkage' between strands of the left-stepping normal fault, revealed through a study of well chips and well logs, occurs through two concealed structures. Both are W-striking faults, with one that runs parallel to Cottonwood Creek and one 0.5 km N of the creek. Injection wells intersect these two transverse structures within the step-over. Stepping and displacement continue to the NW of the known geothermal field, along W-dipping, N-striking faults that cut lower to middle Miocene Hog Creek Formation, consisting of silicic and mafic volcanic rocks. These N-striking faults were likely initiated during initial Oregon-Idaho graben subsidence (15.3-15.1 Ma), with continued development through late Miocene. Bully Creek Formation deposits, middle to upper Miocene lacustrine and pyroclastic rocks, concomitantly filled the sub half-grabens, and they dip gently to moderately eastward. Younger, western Snake River Plain deposits, upper Miocene to Pliocene fluvial, lacustrine, and pyroclastic rocks

  4. Mesa Verde Archaeoastronomy

    Science.gov (United States)

    Munson, Gregory E.

    Mesa Verde archaeoastronomy has been studied for over 100 years through academic research. Investigators have excavated, stabilized, and documented the major dwellings in Mesa Verde National Park. Evidence for astronomical orientation and alignment was found in Cliff Palace and Sun Temple. The level of documentation increased with each new research project. With good documentation practices, together, the research has shown that the cultures of the Mesa Verde were advanced in their social organization and use of astronomy. Consultation with Native American tribal leaders will add significant background to the depth of knowledge that their ancestors possessed.

  5. The Geothermal System of the Arjuno-Welirang Volcano (East Java, Indonesia)

    Science.gov (United States)

    Inguaggiato, S.; Mazzini, A.; Vita, F.

    2015-12-01

    Arjuno-Welirang is a twin strato-volcano system located in the East of Java (Indonesia). It features two main peaks: Arjuno (3339 masl) and Welirang (3156 masl). The last recorded eruptive activity took place in August 1950 from the flanks of Kawah Plupuh and in October 1950 by the NW part of the Gunung Welirang. This strato-volcano is characterized by a solfataric area, with high T-vent fumarole at least up to 220°C, located mainly in the Welirang crater zone where sulphur deposits are abundant. In addition, several hot springs vent from the flanks of the volcano, indicating the presence of a large hydrothermal system During July 2015 we carried out a geochemical field campaign on the Arjuno-Welirang volcano-hydrothermal system area sampling water and dissolved gases from the thermal and cold springs located on the flanks of the volcano and from two high-T fumaroles located on the summit area of Welirang. Hydrothermal springs reveal temperatures up to 53°C and pH between 6.2 and 8.2. The hydrothermal springs show a volatile content (mainly CO2 and He) that is several order of magnitude higher than the Air Saturated Waters values (ASW) indicating a strong gas/water interaction processes between waters of meteoric origin and deep volatiles of volcanic origin. The hydrothermal springs have dissolved helium isotopic values with clear magmatic signature (R/Ra around 7) that is remarkably close to the helium isotope values from the fumaroles (R/Ra= 7.30).

  6. Results of investigations at the Zunil geothermal field, Guatemala: Well logging and brine geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Adams, A.; Dennis, B.; Van Eeckhout, E.; Goff, F.; Lawton, R.; Trujillo, P.E.; Counce, D.; Archuleta, J. (Los Alamos National Lab., NM (USA)); Medina, V. (Instituto Nacional de Electrificacion, Guatemala City (Guatemala). Unidad de Desarollo Geotermico)

    1991-07-01

    The well logging team from Los Alamos and its counterpart from Central America were tasked to investigate the condition of four producing geothermal wells in the Zunil Geothermal Field. The information obtained would be used to help evaluate the Zunil geothermal reservoir in terms of possible additional drilling and future power plant design. The field activities focused on downhole measurements in four production wells (ZCQ-3, ZCQ-4, ZCQ-5, and ZCQ-6). The teams took measurements of the wells in both static (shut-in) and flowing conditions, using the high-temperature well logging tools developed at Los Alamos National Laboratory. Two well logging missions were conducted in the Zunil field. In October 1988 measurements were made in well ZCQ-3, ZCQ-5, and ZCQ-6. In December 1989 the second field operation logged ZCQ-4 and repeated logs in ZCQ-3. Both field operations included not only well logging but the collecting of numerous fluid samples from both thermal and nonthermal waters. 18 refs., 22 figs., 7 tabs.

  7. Faults dominant structure? -Seismic images of the subsurface structure for the Ilan geothermal field in Taiwan.

    Science.gov (United States)

    Chang, Yu-Chun; Shih, Ruey-Chyuan; Wang, Chien-Ying; Kuo, Hsuan-Yu; Chen, Wen-Shan

    2016-04-01

    A prototype deep geothermal power plant is to be constructed at the Ilan plain in northeastern Taiwan. The site will be chosen from one of the two potential areas, one in the west and the other in the eastern side of the plain. The triangle-shaped Ilan plane is bounded by two mountain ranges at the northwest and the south, with argillite and slate outcrops exposed, respectively. The Ilan plane is believed situating in a structure extending area at the southwestern end of the Okinawa Trough. Many studies about subsurface structure of the plain have been conducted for years. The results showed that the thickest sediments, around 900 m, is located at the eastern coast of the plain, at north of the largest river in the plain, the Lanyang river, and then became shallower to the edges of the plain. Since the plane is covered by thick sediments, formations and structures beneath the sediments are barely known. However, the observed high geothermal gradient and the abundant hot spring in the Ilan area indicate that this area is having a high potential of geothermal energy. In order to build up a conceptual model for tracing the possible paths of geothermal water and search for a suitable site for the geothermal well, we used the seismic reflection method to delineate the subsurface structure. The seismic profiles showed a clear unconformity separating the sediments and the metamorphic bedrock, and some events dipping to the east in the bedrock. Seismic images above the unconformity are clear; however, seismic signals in the metamorphic bedrock are sort of ambiguous. There were two models interpreted by using around 10 seismic images that collected by us in the past 3 years by using two mini-vibrators (EnviroVibe) and a 360-channel seismic data acquisition system. In the first model, seismic signals in the bedrock were interpreted as layer boundaries, and a fractured metamorphic layer down the depth of 1200m was thought as the source of geothermal water reservoir. In the

  8. Production and Injection Induced Changes at The Geysers Geothermal Field, CA, USA

    Science.gov (United States)

    Gritto, R.; Jarpe, S.; Boyle, K. L.; Hutchings, L. J.

    2011-12-01

    Induced seismicity related to the exploitation of geothermal fields has caused concern and objection from the public against the operation of geothermal reservoirs in close proximity to population centers. Production at the EGS sites in Basel (Switzerland) was stopped after renewed seismicity caused concern and objection from the public in the city. A planned expansion of the EGS site in Soultz-sous-forêt (France) was suspended after attempts to generate increased permeability through hydrofracturing of the reservoir rock generated an increase in seismicity. As a consequence of these concerns and objections it becomes imperative to understand the differences between naturally occurring and induced events and their relationship to induced stress changes in the reservoir if sustained generation of geothermal energy is the goal. We will address seismicity trends at The Geysers Geothermal Reservoir, CA USA, to understand the role of historical seismicity associated with past injection of water and/or production of steam. The paper will present results of time-lapse tomography to evaluate and quantify temporal changes of the physical parameters in the reservoir. Seismic data collected by the Lawrence Berkeley National Lab (LBNL) seismic network from 2003 through present, were analyzed to delineate regions where compressional and shear-wave velocities indicate changes in reservoir properties.

  9. El Centro Geothermal Utility Core Field Experiment environmental-impact report and environmental assessment

    Energy Technology Data Exchange (ETDEWEB)

    1979-08-01

    The City of El Centro is proposing the development of a geothermal energy utility core field experiment to demonstrate the engineering and economic feasibility of utilizing moderate temperature geothermal heat, on a pilot scale, for space cooling, space heating, and domestic hot water. The proposed facility is located on part of a 2.48 acre (1 hectare) parcel owned in fee by the City in the southeastern sector of El Centro in Imperial County, California. Geothermal fluid at an anticipated temperature of about 250/sup 0/F (121/sup 0/C) will heat a secondary fluid (water) which will be utilized directly or processed through an absorption chiller, to provide space conditioning and water heating for the El Centro Community Center, a public recreational facility located approximately one-half mile north of the proposed well site. The geothermal production well will be drilled to 8500 feet (2590m) and an injection well to 4000 feet (1220m) at the industrially designated City property. Once all relevant permits are obtained it is estimated that site preparation, facility construction, the completion and testing of both wells would be finished in approximately 26 weeks. The environmental impacts are described.

  10. Development of a geothermal resource in a fractured volcanic formation: Case study of the Sumikawa Geothermal Field, Japan. Final report, May 1, 1995--November 30, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Garg, S.K.; Combs, J.; Pritchett, J.W. [and others

    1997-07-01

    The principal purpose of this case study of the Sumikawa Geothermal Field is to document and to evaluate the use of drilling logs, surface and downhole geophysical measurements, chemical analyses and pressure transient data for the assessment of a high temperature volcanic geothermal field. This comprehensive report describes the work accomplished during FY 1993-1996. A brief review of the geological and geophysical surveys at the Sumikawa Geothermal Field is presented (Section 2). Chemical data, consisting of analyses of steam and water from Sumikawa wells, are described and interpreted to indicate compositions and temperatures of reservoir fluids (Section 3). The drilling information and downhole pressure, temperature and spinner surveys are used to determine feedzone locations, pressures and temperatures (Section 4). Available injection and production data from both slim holes and large-diameter wells are analyzed to evaluate injectivity/productivity indices and to investigate the variation of discharge rate with borehole diameter (Section 5). New interpretations of pressure transient data from several wells are discussed (Section 6). The available data have been synthesized to formulate a conceptual model for the Sumikawa Geothermal Field (Section 7).

  11. Connecting Anthropogenic Seismicity Rates To Operational Parameters At The Salton Sea Geothermal Field, Southern California (Invited)

    Science.gov (United States)

    Brodsky, E. E.; Lajoie, L. J.

    2013-12-01

    Geothermal power is generated at several major volcanic fields in California. As efforts to monitor seismicity increase, methods to understand the anthropogenic component need to improve. Ideally, induced earthquake rate should be forecast based on publicly-reported volumes of fluid injection or other operational parameters. At the flash facilities in the Salton Sea Geothermal Field, the total volume of fluid extracted or injected tracks the long-term evolution of seismicity. However, for recent years net fluid volume (extracted-injected) is better correlated with seismicity. After correcting for the variable aftershock rate using an Epidemic-Type Aftershock Sequence model (ETAS), we fit the background earthquake rate with a linear combination of injection and net production rate that allows us to track the secular evolution of the field. The number of earthquakes per fluid volume injected decreases gradually over time. In the Salton Sea Geothermal Field, the new analysis of induced seismicity provides a template for future evaluation of hazard directly based on measureable, controllable operational quantities. The interactions of these anthropogenic events with the larger-scale tectonic and volcanic systems remains to be investigated. Results of the linear model of seismicity based on a combination of net production and injection. (a) Example of observed seismicity rate and model prediction using the reported fluid data and the best-fit linear model. (b) Number of earthquakes triggered per net volume of fluid extracted or total fluid injection.

  12. Pre- and post-exploitation variations in hydrothermal activity in Los Humeros geothermal field, Mexico

    Science.gov (United States)

    Prol-Ledesma, R. M.

    1998-08-01

    Los Humeros geothermal field is a remarkable example of the lack of water-rock equilibrium. Significant variations of hydrothermal activity have occurred before and after exploitation started. Presently, discharged water is not in equilibrium with the alteration suite observed in the reservoir rocks. Hydrothermal minerals identified in core and cuttings define the occurrence of several stages of hydrothermal activity. Cooling at depth is inferred from fluid inclusion and alteration mineralogy data from the wells located nearby Los Humeros fault. Most wells produce a two-phase fluid with excess enthalpy, this accounts for the high CO 2 content observed in the discharged fluid. Sulfur and carbon isotopic data indicate that volatile species in the geothermal fluid have magmatic as well as sedimentary components, while strontium isotopic composition shows that calcium is provided by the andesitic rocks that form the reservoir. As exploitation of the field started, concentration of HCl increased in the discharged fluids. This shows that recharge of the reservoir is not enough to balance the output for production, and drying out of the field may be taking place at depth. The lack of chemical equilibrium and the presence of gases of magmatic origin suggest that Los Humeros is a relatively young geothermal field related to a recent magmatic intrusion.

  13. Subsidence and Stress Change in the Cerro Prieto Geothermal Field, B. C., Mexico

    Science.gov (United States)

    Glowacka, E.; Sarychikhina, O.; Nava, F. A.

    2005-11-01

    Previous works have shown that ground deformation and seismicity in the Cerro Prieto geothermal field (CPGF) are due to both tectonics and field exploitation. Here, we use information about current tectonics and data from precision leveling surveys, to model tectonic and anthropogenic subsidence. Our results show that tectonic subsidence constitutes only ˜4% of the measured subsidence. Anthropogenic subsidence was evaluated using a model of rectangular tensional cracks, based on the hydrological model of the field, together with the Coulomb 2.0 program. From the resulting values of the fissure parameters and from extraction and injection data, we calculate that the volume changes caused by closure of the geothermal and cold water reservoirs account for only ˜3% and ˜7%, respectively, of the volume change which should occur due to extraction. Since 18% of the extracted fluids are reinjected, external recharge must compensate for about 72% of the expected volume reduction. An analysis of the changes in Coulomb stress caused by exploitation of the geothermal field suggest that even though the anthropogenic stresses account for only a fraction of tectonic stresses, they are large enough to trigger seismicity.

  14. Fracture mapping in geothermal fields with long-offset induction logging

    Energy Technology Data Exchange (ETDEWEB)

    Wilt, M.; Takasugi, Shinji; Uchida, Toshihiro [and others

    1997-12-31

    The mapping of producing fractures in a geothermal field is an important technical objective in field development. Locating, orienting, and assessing producing fractures can guide drilling programs and optimize the placement of production and injection wells. A long-offset multicomponent borehole induction resistivity tool capable of surviving the high temperatures encountered in geothermal wells has recently been developed in a NEDO project, {open_quotes}Deep-Seated Geothermal Reservoirs,{close_quotes} and tested in a high temperature environment. Several characteristics of this device make it ideal for detecting producing fractures. Whereas commercial induction logging devices have source-receiver separations of 1 m, this device has multiple sensors with separations up to 8 m, allowing for deeper penetration and the ability to straddle fracture-induced washout zones in boreholes. The three-component measurements also make it possible to map the strike and inclination of nearby fractures and other three-dimensional structures. This, in turn, allows for accurate projection of these structures into the space between wells. In this paper, we describe the design of the tool and show results of a performance test carried out in an oil-field steam flood. Data from vertical sensors are compared to conventional logging results and indicate the recent formation of a low-resistivity zone associated with high temperatures due to steam flood breakthrough. Horizontal field data indicate that the high-temperature zone is irregular in the vicinity of the borehole and more pronounced closest to the steam injector.

  15. The shallow seismic structure of the Larderello geothermal field (Italy) as seen from Receiver Function analysis

    Science.gov (United States)

    Piana Agostinetti, Nicola; Licciardi, Andrea; Piccinini, Davide; Mazzarini, Francesco; Musumeci, Giovanni; Saccorotti, Gilberto

    2017-04-01

    The Larderello field (Tuscany, Italy) is the oldest example in the world of geothermal energy exploitation for industrial purposes. Despite its century long history of exploration and exploitation, the deep structure (4-8km depth) of the Larderello field is still poorly known, due to (a) the lack of resolution of the applied exploration techniques and (b) the lack of interest in the investigation of deep geothermal reservoirs, given the abundant amount of energy extracted from the shallow reservoirs. Recently, the increasing demand of green-energy promoted a renewed interest in the geothermal industrial sector, which translated into new exploration efforts, especially to obtain a detailed characterization of deep geothermal sources. We investigate the seismic structure of the Larderello geothermal field using Receiver Function (RF) analysis. Crustal seismic structures are routinely investigated using the RF methodology, where teleseismic P-wave are analysed to extract P-to-S converted phases that can be related to the propagation of the P-wave across a seismic discontinuity. We compute RF from 26 seismic stations, belonging to both temporary and permanent networks: the GAPSS and RETREAT experiments and the Italian Seismic Network. The RF data-set is migrated at depth and decomposed into azimuthal harmonics. Computing the first, k=0, and the second, k=1, harmonics allows to separate the "isotropic" contribution, due to the change of the isotropic properties of the sampled materials (recorded on the k=0 harmonics), from the "anisotropic" contribution, where the energy is related to the propagation of the P-wave through anisotropic materials (recorded on the k=1 harmonics). Preliminary results allow us: (1) to infer the position of the main S-wave velocity discontinuities in the study area, mainly a shallow Tyrrhenian Moho and a very-low S-wave velocity body in the center of the Larderello dome, at about 5-15km depth; and (2) to map the presence of anisotropic

  16. Spectral reflectance analysis of hydrothermal alteration in drill chips from two geothermal fields, Nevada

    Science.gov (United States)

    Lamb, A. K.; Calvin, W. M.

    2010-12-01

    We surveyed drill chips with a lab spectrometer in the visible-near infrared (VNIR) and short-wave infrared (SWIR) regions, 0.35-2.5 μm, to evaluate hydrothermal alteration mineralogy of samples from two known geothermal fields in western Nevada. Rock is fractured into small pieces or “chips” during drilling and stored in trays by depth interval. The drill chips are used to determine subsurface properties such as lithology, structure, and alteration. Accurately determining alteration mineralogy in the geothermal reservoir is important for indicating thermal fluids (usually associated with fluid pathways such as faults) and the highest temperature of alteration. Hydrothermal minerals, including carbonates, iron oxides, hydroxides, sheet silicates, and sulfates, are especially diagnostic in the VNIR-SWIR region.. The strength of reflectance spectroscopy is that it is rapid and accurate for differentiating temperature-sensitive minerals that are not visually unique. We examined drill chips from two western Nevada geothermal fields: Hawthorne (two wells) and Steamboat Springs (three wells) using an ASD lab spectrometer with very high resolution. The Steamboat Hills geothermal field has produced electricity since 1988 and is well studied, and is believed to be a combination of extensional tectonics and magmatic origin. Bedrocks are Cretaceous granodiorite intruding into older metasediments. Hot springs and other surface expressions occur over an area of about 2.6 km2. In contrast, the Hawthorne geothermal reservoir is a ‘blind’ system with no surface expressions such as hot springs or geysers. The geothermal field is situated in a range front fault zone in an extensional area, and is contained in Mesozoic mixed granite and meta-volcanics. We collected spectra at each interval in the chip trays. Interval length varied between 10’ and 30’. - Endmember analysis and mineral identification were performed -using standard analysis approaches used to map mineralogy

  17. Consideration of geological aspects and geochemical parameters of fluids in Bushdi geothermal field, south of mount Sabalan, NW Iran

    Science.gov (United States)

    Masoumi, Rahim; Calagari, Ali Asghar; Siahcheshm, Kamal; Porkhial, Soheil; Pichler, Thomas

    2017-05-01

    The geothermal field at Bushdi to the south of Sabalan volcano encompasses both cold and hot springs along with surficial steam vents. This geothermal field is situated in a volcanic terrain which includes basaltic and trachy-andesitic lavas and pyroclastics which have undergone considerable faulting during Quaternary times. Regardless of conventional uses, no industrial utilization has been reported from this field yet. In the geothermal fluids Na is the most abundant cation following the trend Na+ >> Ca2+ > K+ > Mg2+. Cl- is the most abundant anion following two trends (1) Cl- >> HCO3- > SO42- and (2) HCO3- > Cl- > SO42-. From a hydrogeochemical point of view the geothermal fluids in the study area can be divided into two categories: (1) Na-Cl and (2) Na-Ca-HCO3. The conic and lenticular shaped travertine deposits around hot springs possessing a Ca2+-Na+-HCO3- composition are the most conspicuous features in this area. According to oxygen and hydrogen stable isotopes (δD and δ18O) data, a large proportion of the fluids in this geothermal system are of meteoric origin. Downward percolation along the brecciated rocks in the fault zones between the mount Sabalan and the Bushdi area can be regarded as the main fluid source for the geothermal system. The geothermal fluids have 3H above 1 TU and hence can be considered as young (modern to sub-modern) waters, with a residence time of less than 63 years.

  18. Identification of linear features at geothermal field based on Segment Tracing Algorithm (STA) of the ALOS PALSAR data

    Science.gov (United States)

    Haeruddin; Saepuloh, A.; Heriawan, M. N.; Kubo, T.

    2016-09-01

    Indonesia has about 40% of geothermal energy resources in the world. An area with the potential geothermal energy in Indonesia is Wayang Windu located at West Java Province. The comprehensive understanding about the geothermal system in this area is indispensable for continuing the development. A geothermal system generally associated with joints or fractures and served as the paths for the geothermal fluid migrating to the surface. The fluid paths are identified by the existence of surface manifestations such as fumaroles, solfatara and the presence of alteration minerals. Therefore the analyses of the liner features to geological structures are crucial for identifying geothermal potential. Fractures or joints in the form of geological structures are associated with the linear features in the satellite images. The Segment Tracing Algorithm (STA) was used for the basis to determine the linear features. In this study, we used satellite images of ALOS PALSAR in Ascending and Descending orbit modes. The linear features obtained by satellite images could be validated by field observations. Based on the application of STA to the ALOS PALSAR data, the general direction of extracted linear features were detected in WNW-ESE, NNE-SSW and NNW-SSE. The directions are consistent with the general direction of faults system in the field. The linear features extracted from ALOS PALSAR data based on STA were very useful to identify the fractured zones at geothermal field.

  19. Field trip guide to the Valles Caldera and its geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Goff, F.E.; Bolivar, S.L.

    1983-12-01

    This field trip guide has been compiled from extensive field trips led at Los Alamos National Laboratory during the past six years. The original version of this guide was designed to augment a workshop on the Valles Caldera for the Continental Scientific Drilling Program (CSDP). This workshop was held at Los Alamos, New Mexico, 5-7 October 1982. More stops were added to this guide to display the volcanic and geothermal features at the Valles Caldera. The trip covers about 90 miles (one way) and takes two days to complete; however, those who wish to compress the trip into one day are advised to use the designated stops listed in the Introduction. Valles Caldera and vicinity comprise both one of the most exciting geothermal areas in the United States and one of the best preserved Quaternary caldera complexes in the world.

  20. 3-D seismic velocity and attenuation structures in the geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Nugraha, Andri Dian [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Syahputra, Ahmad [Geophyisical Engineering, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Fatkhan,; Sule, Rachmat [Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)

    2013-09-09

    We conducted delay time tomography to determine 3-D seismic velocity structures (Vp, Vs, and Vp/Vs ratio) using micro-seismic events in the geothermal field. The P-and S-wave arrival times of these micro-seismic events have been used as input for the tomographic inversion. Our preliminary seismic velocity results show that the subsurface condition of geothermal field can be fairly delineated the characteristic of reservoir. We then extended our understanding of the subsurface physical properties through determining of attenuation structures (Qp, Qs, and Qs/Qp ratio) using micro-seismic waveform. We combined seismic velocities and attenuation structures to get much better interpretation of the reservoir characteristic. Our preliminary attanuation structures results show reservoir characterization can be more clearly by using the 3-D attenuation model of Qp, Qs, and Qs/Qp ratio combined with 3-D seismic velocity model of Vp, Vs, and Vp/Vs ratio.

  1. 3-D seismic velocity and attenuation structures in the geothermal field

    Science.gov (United States)

    Nugraha, Andri Dian; Syahputra, Ahmad; Fatkhan, Sule, Rachmat

    2013-09-01

    We conducted delay time tomography to determine 3-D seismic velocity structures (Vp, Vs, and Vp/Vs ratio) using micro-seismic events in the geothermal field. The P-and S-wave arrival times of these micro-seismic events have been used as input for the tomographic inversion. Our preliminary seismic velocity results show that the subsurface condition of geothermal field can be fairly delineated the characteristic of reservoir. We then extended our understanding of the subsurface physical properties through determining of attenuation structures (Qp, Qs, and Qs/Qp ratio) using micro-seismic waveform. We combined seismic velocities and attenuation structures to get much better interpretation of the reservoir characteristic. Our preliminary attanuation structures results show reservoir characterization can be more clearly by using the 3-D attenuation model of Qp, Qs, and Qs/Qp ratio combined with 3-D seismic velocity model of Vp, Vs, and Vp/Vs ratio.

  2. Slope stability analysis of landslide in Wayang Windu Geothermal Field, Pangalengan, West Java Province, Indonesia

    Science.gov (United States)

    Yuhendar, A. H.; Wusqa, U.; Kartiko, R. D.; Raya, N. R.; Misbahudin

    2016-05-01

    Large-scale landslide occurred in Margamukti village, Pangalengan, Bandung Regency, West Java Province, Indonesia. The landslide damaged geothermal gas pipeline along 300 m in Wayang Windu Geothermal Field. Based on field observation, landslide occured in rotational sliding movement. Laboratory analysis were conducted to obtain the characteristics of the soil. Based on the condition of the landslide in this area, the Factor of Safety can be simulated by the soil mechanics approach. Factor of safety analysis based on soil cohesion and internal friction angle was conducted using manual sensitivity analysis for back analysis. The analysis resulted soil cohesion in critical condition (FS<1) is 6.01 kPa. This value is smaller than cohesion of undisturbed slope soil sample. Water from rainfall is the most important instability factors in research area. Because it decreases cohesion in soils and increases weight and pore water pressure in granular media.

  3. Fracture mapping in geothermal fields with long-offset induction logging

    Energy Technology Data Exchange (ETDEWEB)

    Wilt, M. [Electromagnetic Instruments, Inc., Richmond, CA (United States); Takasugi, Shinji [Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan); Uchida, Toshihiro [New Energy and Industrial Technology Development Organization, Tokyo (Japan); Kasameyer, P. [Lawrence Livermore National Lab., CA (United States); Lee, Ki Ha; Lippmann, M. [Lawrence Berkeley National Lab., CA (United States)

    1997-01-01

    The mapping of producing fractures in a geothermal field is an important technical objective in field development. Locating, orientating, and assessing producing fractures can guide drilling programs and optimize the placement of production and injection wells. A long-offset multicomponent borehole induction resistivity tool capable of surviving the high temperatures encountered in geothermal wells has recently been developed and tested in a high temperature environment. Several characteristics of this device make it ideal for detecting producing fractures. Whereas commercial induction logging devices have strong source-receiver separations of 1 m, this device has multiple sensors with separation of 8 m, allowing for deeper penetrations and the ability to straddle fracture-induced washout zones in boreholes. The three-component measurements also make it possible to map the strike and inclination of nearby fractures and other three-dimensional structures. This in turn allows for accurate projection of these structures into the space between wells.

  4. Forming Condition and Main Heat Reservoir Resource of Lindian Geothermal Field in Heilongj iang Provinc%黑龙江省林甸地热田形成条件及主要热储层资源量

    Institute of Scientific and Technical Information of China (English)

    常立新

    2015-01-01

    黑龙江省林甸地热田是我国高寒地区特大型中低温地热田,是全国著名的温泉之乡。地热田区域内具有形成地热田的良好地质条件。较高的地温场为地热田提供了能源保障;区域构造上存在乌裕尔和黑鱼泡两个深凹陷,是东西北三面地下水渗入汇聚的中心部位;北部物源中的高孔渗砂体为地热田提供了良好的热水储集空间;盆缘外侧的大小兴安岭中的多条河流为地热田提供了充足的水源补给。通过模拟计算,林甸地热田主要热储层地热水资源量为1760.62×108 m3。%Heilongjiang Province Lindian geothermal fields are the super-huge type medium-low temperature geothermal fields in alpine region of our country,also are the famous hot spring town.It has good geological conditions to form the geothermal field within the area.Higher geothermal field provide energy security for the geothermal fields;two deep depressions presenting in regional structure,that is Wuyuer and Heiyupao,they are the infiltration convergence central part of groundwater from east,west and north three sides;high porosity and permeability sand bodies of northern provenance provides the good heat water reservoir space for the geothermal fields;the many rivers from Great Khingan and Lesser Khin-gan Range in the outside of the basin margin provide the sufficient water supply for the geothermal fields. Through simulation,the geothermal water volume of major heat reservoir is 1760.62 × 108 m3 in Lindian geothermal fields.

  5. Improved Detection of Microearthquakes: Application of Matched Field Processing (MFP) to Traditional and Enhanced Geothermal Systems

    Science.gov (United States)

    Templeton, D. C.; Harris, D.; Goebel, M.

    2013-12-01

    We investigate the microseismicity in both traditional and Enhanced Geothermal Systems (EGS) and compare the temporal distribution of microseismic events to well fluid injection data. We apply the empirical and model-based Matched Field Processing (MFP) methods to continuous seismic data from the Salton Sea geothermal field and the DOE Newberry EGS site. MFP is a non-traditional event detection method that can identify more and smaller events than traditional detection methods alone. The empirical MFP method uses known catalog events as master templates to identify new microearthquakes while the model-based MFP method uses synthetic sources computed across a subsurface 3D grid as master templates. Salton Sea data between January 2008 and December 2011 was downloaded off the SCEDC website and high-quality master events were identified from the online catalog. We created empirical matched field steering vector calibrations for 7 three-component stations within the Salton Sea Geothermal Field. The original Salton Sea earthquake catalog identified 4202 events. When we applied the empirical MFP technique to the same data, we identified 5005 additional events (~119% more events). We compare the results from this traditional geothermal area with results obtained from the Newberry EGS site, for which we have 8 three-component stations. The Newberry catalog originally identified 204 events in 3 months while the MFP technique identified 249 additional events (~122% more events). We will compare the results from using the empirical MFP method at the Newberry EGS site with results obtained from using model-based master templates. Additionally, we compare the number of events in the improved earthquake catalogs with available fluid injection data. This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  6. Seismicity studies in the region of the Cerro Prieto Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Albores, A.; Reyes, A.; Brune, J.N.; Gonzalez, J.; Garcilazo, L.; Suarez, F.

    1980-01-01

    This paper reports results from seismicity studies in the region of the Cerro Prieto geothermal field. These studies were conducted with local short period seismic arrays during 1974-1975 and 1977-1978. During the latter period, horizontal seismometers were used for better control on the S-wave arrival times. Locations were obtained for about 200 events and composite fault plane solutions were obtained for five groups of events. 16 refs.

  7. Matched Filter Detection of Microseismicity at Ngatamariki and Rotokawa Geothermal Fields, Central North Island, New Zealand

    Science.gov (United States)

    Hopp, C. J.; Savage, M. K.; Townend, J.; Sherburn, S.

    2016-12-01

    Monitoring patterns in local microseismicity gives clues to the existence and location of subsurface structures. In the context of a geothermal reservoir, subsurface structures often indicate areas of high permeability and are vitally important in understanding fluid flow within the geothermal resource. Detecting and locating microseismic events within an area of power generation, however, is often challenging due to high levels of noise associated with nearby power plant infrastructure. In this situation, matched filter detection improves drastically upon standard earthquake detection techniques, specifically when events are likely induced by fluid injection and are therefore near-repeating. Using an earthquake catalog of 637 events which occurred between 1 January and 18 November 2015 as our initial dataset, we implemented a matched filtering routine for the Mighty River Power (MRP) geothermal fields at Rotokawa and Ngatamariki, central North Island, New Zealand. We detected nearly 21,000 additional events across both geothermal fields, a roughly 30-fold increase from the original catalog. On average, each of the 637 template events detected 45 additional events throughout the study period, with a maximum number of additional detections for a single template of 359. Cumulative detection rates for all template events, in general, do not mimic large scale changes in injection rates within the fields, however we do see indications of an increase in detection rate associated with power plant shutdown at Ngatamariki. Locations of detected events follow established patterns of historic seismicity at both Ngatamariki and Rotokawa. One large cluster of events persists in the southeastern portion of Rotokawa and is likely bounded to the northwest by a known fault dividing the injection and production sections of the field. Two distinct clusters of microseismicity occur in the North and South of Ngatamariki, the latter appearing to coincide with a structure dividing the

  8. GEOTHERMICS GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>20101802 Fang Bin (China University of Geosciences,Beijing 100083,China);Yang Yunjun Characteristics and Resource Evaluation of the Jiwa Geothermal Field in Central Qiangtang,Northern Tibet,China (Geological Bulletin of China,ISSN1671-

  9. Microearthquake Study of the Salton Sea Geothermal Field, California: Evidence of Stress Triggering - Masters Thesis

    Energy Technology Data Exchange (ETDEWEB)

    Holland, Austin Adams

    2002-02-01

    A digital network of 24 seismograph stations was operated from September 15, 1987 to September 30, 1988, by Lawrence Livermore National Laboratory and Unocal as part of the Salton Sea Scientific Drilling Project to study seismicity related to tectonics and geothermal activity near the drilling site. More than 2001 microearthquakes were relocated in this study in order to image any pervasive structures that may exist within the Salton Sea geothermal field. First, detailed velocity models were obtained through standard 1-D inversion techniques. These velocity models were then used to relocate events using both single event methods and Double-Differencing, a joint hypocenter location method. An anisotropic velocity model was built from anisotropy estimates obtained from well logs within the study area. During the study period, the Superstition wills sequence occurred with two moderate earthquakes of MS 6.2 and MS 6.6. These moderate earthquakes caused a rotation of the stress field as observed from the inversion of first motion data from microearthquakes at the Salton Sea geothermal field. Coulomb failure analysis also indicates that microearthquakes occurring after the Superstition Hills sequence are located within a region of stress increase suggesting stress triggering caused by the moderate earthquakes.

  10. Temporal changes in shear velocity from ambient noise at New Zealand geothermal fields

    Science.gov (United States)

    Civilini, F.; Savage, M. K.; Townend, J.

    2016-12-01

    We use ambient noise to compare shear velocity changes with geothermal production processes at the Ngatamariki and Rotokawa geothermal fields, located in the central North Island of New Zealand. We calculate shear velocity changes through an analysis of cross correlation functions of diffusive seismic wavefields between stations, which are proportional to Green's functions of the station path. Electricity production at Ngatamariki uses an 82 MW binary type power station manufactured by Ormat Technologies, which began operations in mid-2013 and is owned and operated by Mighty River Power. The "Nga Awa Purua" triple flash power plant at the Rotokawa geothermal field was established in 2010 with parnership between Mighty River Power and Tauhara North No. 2 trust and currently operates 174 MW of generation. The seismometers of both networks, deployed primarily to observe microseismicity within the field, were installed prior to well stimulation and the start of production. Although cultural noise dominates the energy spectrum, a strong natural ambient noise signal can be detected when filtering below 1 Hz. Despite similar noise settings, the signal-to-noise ratio of cross correlation stacks at Rotokawa was more than two times greater than at Ngatamariki. We use stacks of cross correlations between stations prior to the onset of production as references, and compare them with cross correlations of moving stacks in time periods of well stimulation and the onset of electricity production.

  11. Three-dimensional inversion of magnetotelluric data from the Coso Geothermal Field, based on a finite difference Gauss-Newton method parallelized on a multicore workstation

    Science.gov (United States)

    Maris, Virginie

    An existing 3-D magnetotelluric (MT) inversion program written for a single processor personal computer (PC) has been modified and parallelized using OpenMP, in order to run the program efficiently on a multicore workstation. The program uses the Gauss-Newton inversion algorithm based on a staggered-grid finite-difference forward problem, requiring explicit calculation of the Frechet derivatives. The most time-consuming tasks are calculating the derivatives and determining the model parameters at each iteration. Forward modeling and derivative calculations are parallelized by assigning the calculations for each frequency to separate threads, which execute concurrently. Model parameters are obtained by factoring the Hessian using the LDLT method, implemented using a block-cyclic algorithm and compact storage. MT data from 102 tensor stations over the East Flank of the Coso Geothermal Field, California are inverted. Less than three days are required to invert the dataset for ˜ 55,000 inversion parameters on a 2.66 GHz 8-CPU PC with 16 GB of RAM. Inversion results, recovered from a halfspace rather than initial 2-D inversions, qualitatively resemble models from massively parallel 3-D inversion by other researchers and overall, exhibit an improved fit. A steeply west-dipping conductor under the western East Flank is tentatively correlated with a zone of high-temperature ionic fluids based on known well production and lost circulation intervals. Beneath the Main Field, vertical and north-trending shallow conductors are correlated with geothermal producing intervals as well.

  12. Solar Field Optical Characterization at Stillwater Geothermal/Solar Hybrid Plant

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Guangdong [National Renewable Energy Laboratory,15013 Denver West Parkway,Golden, CO 80401e-mail: Guangdong.Zhu@nrel.gov; Turchi, Craig [National Renewable Energy Laboratory,15013 Denver West Parkway,Golden, CO 80401

    2017-01-27

    Concentrating solar power (CSP) can provide additional thermal energy to boost geothermal plant power generation. For a newly constructed solar field at a geothermal power plant site, it is critical to properly characterize its performance so that the prediction of thermal power generation can be derived to develop an optimum operating strategy for a hybrid system. In the past, laboratory characterization of a solar collector has often extended into the solar field performance model and has been used to predict the actual solar field performance, disregarding realistic impacting factors. In this work, an extensive measurement on mirror slope error and receiver position error has been performed in the field by using the optical characterization tool called Distant Observer (DO). Combining a solar reflectance sampling procedure, a newly developed solar characterization program called FirstOPTIC and public software for annual performance modeling called System Advisor Model (SAM), a comprehensive solar field optical characterization has been conducted, thus allowing for an informed prediction of solar field annual performance. The paper illustrates this detailed solar field optical characterization procedure and demonstrates how the results help to quantify an appropriate tracking-correction strategy to improve solar field performance. In particular, it is found that an appropriate tracking-offset algorithm can improve the solar field performance by about 15%. The work here provides a valuable reference for the growing CSP industry.

  13. Open questions on the origin of life at anoxic geothermal fields.

    Science.gov (United States)

    Mulkidjanian, Armen Y; Bychkov, Andrew Yu; Dibrova, Daria V; Galperin, Michael Y; Koonin, Eugene V

    2012-10-01

    We have recently reconstructed the 'hatcheries' of the first cells by combining geochemical analysis with phylogenomic scrutiny of the inorganic ion requirements of universal components of modern cells (Mulkidjanian et al. Proc Natl Acad Sci U S A 109:E821-830, 2012). These ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K⁺, Zn²⁺, Mn²⁺, and phosphate. Thus, protocells must have evolved in habitats with a high K⁺/Na⁺ ratio and relatively high concentrations of Zn, Mn and phosphorous compounds. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapor-dominated zones of inland geothermal systems. Under an anoxic, CO₂-dominated atmosphere, the ionic composition of pools of cool, condensed vapor at anoxic geothermal fields would resemble the internal milieu of modern cells. Such pools would be lined with porous silicate minerals mixed with metal sulfides and enriched in K⁺ ions and phosphorous compounds. Here we address some questions that have appeared in print after the publication of our anoxic geothermal field scenario. We argue that anoxic geothermal fields, which were identified as likely cradles of life by using a top-down approach and phylogenomics analysis, could provide geochemical conditions similar to those which were suggested as most conducive for the emergence of life by the chemists who pursuit the complementary bottom-up strategy.

  14. Analysis of Injection-Backflow Tracer Tests in Fractured Geothermal Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Kocabas, I.; Horne, R.N.

    1987-01-20

    Tracer tests have been an important technique for determining the flow and reservoir characteristics in various rock matrix systems. While the interwell tracer tests are aimed at the characterization of the regions between the wells, single-well injection-backflow tracer tests may be useful tools of preliminary evaluation, before implementing long term interwell tracer tests. This work is concerned with the quantitative evaluation of the tracer return profiles obtained from single well injection-backflow tracer tests. First, two mathematical models of tracer transport through fractures, have been reviewed. These two models are based on two different principles: Taylor Dispersion along the fracture and simultaneous diffusion in and out of the adjacent matrix. Then the governing equations for the transport during the injection-backflow tests have been solved. Finally the results were applied to field data obtained from Raft River and East Mesa geothermal fields. In order to determine the values of the parameters of the models that define the transport mechanisms through fractures a non-linear optimization technique was employed. 26 refs., 10 figs.

  15. Hydrothermal alteration of sediments associated with surface emissions from the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Valette-Silver, J.N.; Esquer P., I.; Elders, W.A.; Collier, P.C.; Hoagland, J.R.

    1981-01-01

    A study of the mineralogical changes associated with these hydrothermal vents was initiated with the aim of developing possible exploration tools for geothermal resources. The Cerro Prieto reservoir has already been explored by extensive deep drilling so that relationships between surface manifestations and deeper hydrothermal processes could be established directly. Approximately 120 samples of surface sediments were collected both inside and outside of the vents. The mineralogy of the altered sediments studied appears to be controlled by the type of emission. A comparison between the changes in mineralogy due to low temperature hydrothermal activity in the reservoir, seen in samples from boreholes, and mineralogical changes in the surface emission samples shows similar general trends below 180 C: increase of quartz, feldspar and illite, with subsequent disappearance of kaolinite, montmorillonite, calcite and dolomite. These mineral assemblages seem to be characteristic products of the discharge from high intensity geothermal fields.

  16. Plant adaptation to extreme environments: the example of Cistus salviifolius of an active geothermal alteration field.

    Science.gov (United States)

    Bartoli, Giacomo; Bottega, Stefania; Forino, Laura M C; Ciccarelli, Daniela; Spanò, Carmelina

    2014-02-01

    Cistus salviifolius is able to colonise one of the most extreme active geothermal alteration fields in terms of both soil acidity and hot temperatures. The analyses of morpho-functional and physiological characters, investigated in leaves of plants growing around fumaroles (G leaves) and in leaves developed by the same plants after transfer into growth chamber under controlled conditions (C leaves) evidenced the main adaptive traits developed by this pioneer plant in a stressful environment. These traits involved leaf shape and thickness, mesophyll compactness, stomatal and trichome densities, chloroplast size. Changes of functional and physiological traits concerned dry matter content, peroxide and lipid peroxidation, leaf area, relative water and pigment contents. A higher reducing power and antioxidant enzymatic activity were typical of G leaves. Though the high levels of stress parameters, G leaves showed stress-induced specific morphogenic and physiological responses putatively involved in their surviving in active geothermal habitats.

  17. Geology Structure Identification based on Polarimetric SAR (PolSAR) Data and Field Based Observation at Ciwidey Geothermal Field

    Science.gov (United States)

    Pradipta, R. A.; Saepuloh, A.; Suryantini

    2016-09-01

    Geological structure observation is difficult to be conducted at Quaternary volcanic field due to the classical problem at tropical region such as intensive erosion, dense vegetation covers, and rough terrain. The problem hampers the field observation especially for geological structures mapping. In order to overcome the problems, an active remote sensing technology based on Polarimetric Synthetic Aperture Radar (PolSAR) data was used in this study. The longer wavelength of microwave than optical region caused the SAR layer penetration higher than optics. The Ciwidey Geothermal Field, Indonesia was selected as study area because of the existence of surface manifestations with lack information about the control of geological structures to the geothermal system. Visual interpretation based on composite polarization modes was applied to identify geological structures at study area. The color composite Red-Green-Blue for HV-HH-VV polarizations provided highest texture and structural features among the other composite combination. The Linear Features Density (LFD) map was also used to interpret the fractures zones. The calculated LFD showed high anomaly about 3.6 km/km2 with two strike directions NW-SE and NE-SW. Interestingly, the surface geothermal manifestation agreed with the low anomaly of LFD. The geological structures consisted of ten faults were successfully detected and mapped. The faults type mainly are oblique-slip with strike directions NE-SW and NW-SE.

  18. Reservoir Characterization around Geothermal Field, West Java, Indonesia Derived from 4-D Seismic Tomography

    Science.gov (United States)

    Verdhora Ry, Rexha; Nugraha, A. D.

    2016-01-01

    Observation of micro-seismic events induced by intensive geothermal exploitation in a particular geothermal field, located in West Java region, Indonesia was used to detect the fracture and permeability zone. Using local monitoring seismometer network, tomographic inversions were conducted for the three-dimensional Vp, Vs, and Vp/Vs structure of the reservoir for January - December 2007, January - December 2008, and January - December 2009. First, hypocenters location was relocated using joint hypocenter determination (JHD) method in purpose to estimate best location. Then, seismic tomographic inversions were conducted using delay time tomography for dataset of every year respectively. The travel times passing through the three-dimensional velocity model were calculated using ray tracing pseudo-bending method. Norm and gradient damping were added to constrain blocks without ray and to produce smooth solution model. The inversion algorithm was developed in Matlab environment. Our tomographic inversion results from 3-years of observations indicate the presence of low Vp, low Vs, and low Vp/Vs ratio at depths of about 1 - 3 km below sea level. These features were interpreted may be related to steam-saturated rock in the reservoir area of this geothermal field. The locations of the reservoir area were supported by the data of well- trajectory, where the zones of high Vp/Vs were observed around the injection wells and the zones of low Vp/Vs were observed around the production wells. The extensive low Vp/Vs anomaly that occupies the reservoir is getting stronger during the 3-years study period. This is probably attributed to depletion of pore liquid water in the reservoir and replacement with steam. Continuous monitoring of Vp, Vs, and Vp/Vs is an effective tool for geothermal reservoir characterization and depletion monitoring and can potentially provide information in parts of the reservoir which have not been drilled.

  19. Seismicity and deformation in the Coso Geothermal field from 2000 to 2012

    Science.gov (United States)

    Kaven, J. Ole; Hickman, Stephen H.; Davatzes, Nicholas C.

    2015-04-01

    Induced micro-seismicity in geothermal reservoirs, in particular in enhanced geothermal systems (EGS), is an intended byproduct of injection and production, as it often indicates the generation of permeability pathways on either pre-existing or newly generated faults and fractures. The hazard of inducing an earthquake large enough to cause damage to surface structures, however, is not easily avoided and has led to termination of geothermal projects. To explore the physical processes leading to damaging earthquakes, we investigate the evolution of seismicity and the factors controlling the migration, moment release rate, and structure within the seismicity in the Coso Geothermal Field (CGF). The CGF has been in production since the 1980s and includes both naturally occurring geothermal resources and portions of the reservoir that are EGS projects. We report on seismicity in the CGF that has been relocated with high precision double-difference relocation and simultaneous velocity inversion to understand the reservoir compartmentalization, in particular, where boundaries to flow exist both vertically and horizontally. We also calculate moment magnitudes (Mw) from the initial displacement pulse of the seismograms to relate moment directly to the deformation. We find that two distinct compartments form the CGF, which are divided by an aseismic gap that also shows a relatively low Vp/Vs ratio. Further, we find that events with Mw> 3.5 tend to map onto larger fault structures that are imaged by the relocated seismicity. We relate the temporal and spatial migration of moment release rate to the injection and production records in the reservoir by employing a thermo-poro-elastic finite element model in which the compartment boundaries are defined by the seismicity. We find that pore pressure effects alone are not responsible for the migration of seismicity and that poro-elastic and thermo-elastic strain changes can account for more of the observed moment release rate than

  20. Geothermal potential and origin of natural thermal fluids in the northern Lake Abaya area, Main Ethiopian Rift, East Africa

    Science.gov (United States)

    Minissale, A.; Corti, G.; Tassi, F.; Darrah, T. H.; Vaselli, O.; Montanari, D.; Montegrossi, G.; Yirgu, G.; Selmo, E.; Teclu, A.

    2017-04-01

    In this study, the occurrence, chemical composition, origin and geothermal significance of thermal springs and fumaroles naturally discharging in the area located north of the Lake Abaya (western margin of the Main Ethiopian Rift, East Africa) are reviewed in relation with recent tectonics. All thermal springs showed a dominantly Na-HCO3 composition, consistent with observations dating from at least 1972, and most of them displayed a narrow range of δD and δ18O isotopic compositions for water similar to regional meteoric origins. These observations suggest that water-rock interaction processes occur in all aquifers and dominate the contributions of water that actively circulate within thermal fluids, and also suggest a similar elevation of groundwater recharge throughout the study area. Most of the thermal springs are dominated by a CO2-rich gas phase and discharge along the active faults bordering the western edge of the Main Ethiopian Rift valley. The δ13C values of CO2 and the 3He/4He isotopic ratios are consistent with the presence of mantle-derived fluids similar to what is observed in many other areas along the kinematically active African Rift, especially within Ethiopia. The application of geothermometric techniques in the liquid and the gas phases suggests the presence of a deep reservoir in which the fluids equilibrated at a maximum temperature of approximately 180 °C. Additionally, the presence of fumaroles at boiling temperatures and water/mud boiling pools in several places suggests that the geothermal reservoir is positioned at a relatively shallow depth and likely located in the western side of the study area. The analysis of data collected throughout time reveals that the waters of Lake Abaya have experienced an increase in salinity of 20% paralleled contemporaneously with a decrease in pH and δ18O and δD of water in the last 40 years; these changes do not appear to be related to climate change-induced increases in temperature or evaporation

  1. Relationship between water chemistry and sediment mineralogy in the Cerro Prieto geothermal field: a preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Valette-Silver, J.N. (Univ. de Perpignan, France); Thompson, J.M.; Ball, J.W.

    1981-01-01

    The chemical compositions of waters collected from the Cerro Prieto geothermal production wells and hydrothermal emanations are different. Compared to the Cerro Prieto well waters, the surficial waters generally contain significantly less potassium, slightly less calcium and chloride, and significantly more magnesium and sulfate. In comparison to the unaltered sediments, the changes in the mineralogy of the altered sediments appear to be controlled by the type of emanation (well, spring, mud pot, geyser, fumarole, or cold pool). However, an increase in quartz and potassium feldspar percentages seems to be characteristic of the majority of the sediments in contact with geothermal fluids. Preliminary attempts to model the chemical processes occurring in the Cerro Prieto geothermal field using chemical equilibrium calculations are reported. For this purpose the chemical compositions of thermal waters (well and surficial emanation) were used as input data to make calculations with SOLMNEQ and WATEQ2 computer programs. Then the theoretical mineral composition of altered sediments was predicted and compared to the mineralogy actually observed in the solid samples.

  2. A method of fundamental solutions in poroelasticity to model the stress field in geothermal reservoirs

    CERN Document Server

    Augustin, Matthias Albert

    2015-01-01

    This monograph focuses on the numerical methods needed in the context of developing a reliable simulation tool to promote the use of renewable energy. One very promising source of energy is the heat stored in the Earth’s crust, which is harnessed by so-called geothermal facilities. Scientists from fields like geology, geo-engineering, geophysics and especially geomathematics are called upon to help make geothermics a reliable and safe energy production method. One of the challenges they face involves modeling the mechanical stresses at work in a reservoir. The aim of this thesis is to develop a numerical solution scheme by means of which the fluid pressure and rock stresses in a geothermal reservoir can be determined prior to well drilling and during production. For this purpose, the method should (i) include poroelastic effects, (ii) provide a means of including thermoelastic effects, (iii) be inexpensive in terms of memory and computational power, and (iv) be flexible with regard to the locations of data ...

  3. Temperature-depth relationships based on log data from the Los Azufres geothermal field, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Estrada, G.; Lopez-Hernandez, A. [Comision Federal de Electricidad (Mexico); Prol-Ledesma, R.M. [Universidad Nacional Autonoma de Mexico (Mexico)

    2001-02-01

    Equilibrium temperatures based on log data acquired during drilling stops in the Los Azufres geothermal field were used to study the relationship between temperature, depth and conductive heat flow that differentiate production from non-production areas. Temperature and thermal conductivity data from 62 geothermal wells were analyzed, displaying temperature-depth, gradient-depth, and ternary temperature-gradient-depth plots. In the ternary plot, the production wells of Los Azufres are located near the temperature vertex, where normalized temperatures are over 0.50 units, or where the temperature gradient is over 165{sup o}C/ km. In addition, the temperature data were used to estimate the depth at which 600{sup o}C could be reached (5-9 km) and the regional background conductive heat flow ({approx_equal}106 mW/m{sup 2}). Estimates are also given for the conductive heat flow associated with the conductive cooling of an intrusive body ({approx_equal}295 mW/m{sup 2}), and the conductive heat flow component in low-permeability blocks inside the reservoir associated with convection in limiting open faults (from 69 to 667 mW/m{sup 2}). The method applied in this study may be useful to interpret data from new geothermal areas still under exploration by comparing with the results obtained from Los Azufres. (author)

  4. Preliminary isotopic studies of fluids from the Cerro Prieto geothermal field

    Science.gov (United States)

    Truesdell, A.H.; Rye, R.O.; Pearson, F.J.; Olson, E.R.; Nehring, N.L.; Whelan, J.F.; Huebner, M.A.; Coplen, T.B.

    1979-01-01

    Preliminary isotopic studies of Cerro Prieto geothermal fluids and earlier studies of Mexicali Valley ground waters suggest local recharge of the geothermal system from the area immediately to the west. Oxygen isotope exchange of water with reservoir rock minerals at temperatures increasing with depth has produced fluids with oxygen-18 contents increasing with depth, and pressure drawdown in the southeastern part of the field has allowed lower oxygen-18 fluids to invade the production aquifer from above. The contents of tritium and carbon-14 in the fluid suggest only that the age of the fluid is between 50 and 10,000 years. The isotopic compositions of carbon and sulfur are consistent with a magmatic origin of these elements but a mixed sedimentary-organic origin appears more likely for carbon and is also possible for sulfur. Investigations of the isotopic compositions of geothermal and cold ground waters continue and are being expanded as fluids become available and as separation and analysis methods are improved. ?? 1979.

  5. Electronic geothermal atlases of Asian Russia

    Institute of Scientific and Technical Information of China (English)

    Albert DDuchkov; Michael Zheleznjak; Ludmila SSokolova

    2014-01-01

    Generalized geothermal data was used to produce two electronic atlases for Asian Russia, Geothermal Atlas of Siberia (GAS) (1995-2000) and Geothermal Atlas for Siberia and Russian Far East (GASRFE) (2009-2012). The atlases include heat flow maps, temperatures at depths of 0.5, 1, 2, 3, 5 km and lower boundary of permafrost. Quantitative values of pa-rameters are presented as isolines (GAS) and symbols (GASRFE). GAS website is located at the Trofimuk Institute (www.ipgg.sbras.ru/ru/institute/structure/geophysics/natural-fields). GASRFE provides the most complete geothermal data on Asian Russia, which has been growing for the last 50 years, and is published on the Internet at http://maps.nrcgit.ru/geoterm. In this atlas, data about the depth of permafrost lower boundary ("zero"isotherm) are pre-sented for the first time.

  6. Distributed Acoustic Sensing Technology in a Magmatic Geothermal Field - First Results From a Survey in Iceland

    Science.gov (United States)

    Reinsch, Thomas; Jousset, Philippe; Henninges, Jan; Blanck, Hanna

    2016-04-01

    Seismic methods are particularly suited for investigating the Earth's subsurface. Compared to surface-measurements , wellbore measurements can be used to acquire more detailed information about rock properties and possible fluid pathways within a geothermal reservoir. For high temperature geothermal wells, however, ambient temperatures are often far above the operating temperature range of conventional geophones. One way to overcome this limitation is the application of fiber optic sensor systems, where only the passive optical fiber is subjected to downhole conditions. Their applicability is thus determined by the operating temperature range of the optical fiber. Choosing appropriate fibers, such sensor systems can be operated at temperatures far above 200°C. Along an optical fiber, the distributed acoustic sensing technology (DAS) can be used to acquire acoustic signals with a high spatial and temporal resolution. Previous experiments have shown that the DAS technology is well suited for active seismic measurements. Within the framework of the EC funded project IMAGE, a fiber optic cable was deployed in a newly drilled geothermal well (RN-34) within the Reykjanes geothermal field, Iceland. Additionally, a >15 km fiber optic cable, already available at the surface, was connected to a DAS read-out unit. Acoustic data was acquired continuously for 9 days. Hammer shots were performed at the wellhead as well as along the surface cable in order to locate individual acoustic traces and calibrate the spatial distribution of the acoustic information. During the monitoring period both signals from on- and offshore explosive sources and natural seismic events could be recorded. We compare the fiber optic data to conventional seismic records from a dense seismic network deployed on the Reykjanes in the course of the IMAGE project. Here, first results from the seismic survey will be presented.

  7. Imperial County geothermal development semi-annual report, October 1, 1980-March 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    The current geothermal progress in Imperial County is reported. Three areas are reported: Geothermal Administration, Geothermal Planning, and other Geothermal Activities. Geothermal Administration addresses the status of the Imperial Valley Environmental Project (IVEP) transfer, update of the Geothermal Resource Center, and findings of Geothermal field inspections. In addition, the cooperative efforts between industry and the County; Master EIR for the Salton Sea KGRA and the resurveying of the subsidence detection network are covered. Geothermal Planning addresses a Board of Supervisor action on the Union Oil Geothermal Production Permit for 16 wells in the Salton Sea KGRA and a permit for Southern California Edison 10 megawatts power plant in the Salton Sea KGRA. Planning Commission action covers: Amendment of Magma Power's 49 megawatts Geothermal Production Permit to 28 megawatt power plant and relocation of the plant and wells within the Salton Sea KGRA; Exploration permit to Occidental Geothermal for four exploratory wells in East Brawley; Geothermal Production Permit to Southern California Edison to operate a 10 megawatt power plant in the Salton Sea KGRA; and Geothermal production permit to Union Oil for 16 production-injection wells in the Salton Sea KGRA. Lastly, EIR exemptions to CEQA were granted to Chevron for 70 shallow temperature observation holes and Union for fifteen. Other Geothermal Activity addresses the County Direct Heat Development study; the solicitation for district heating and cooling proposals; the new Geothermal Class II-1 disposal site; the DOE Region IX meeting in Tucson; and USGA designating a new KGRA, the East Brawley KGRA, the Westmorland KGRA, and revising the southern border of the Salton Sea KGRA.

  8. Autumn Daily Characteristics of Land Surface Heat and Water Exchange over the Loess Plateau Mesa in China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Loess Plateau, located in northern China, has a significant impact on the climate and ecosystem evolvement over the East Asian continent. In this paper, the preliminary autumn daily characteristics of land surface energy and water exchange over the Chinese Loess Plateau mesa region are evaluated by using data collected during the Loess Plateau land-atmosphere interaction pilot experiment (LOPEX04), which was conducted from 25 August to 12 September 2004 near Pingliang city, Gansu Province of China. The experiment was carried out in a region with a typical landscape of the Chinese Loess Plateau, known as "loess mesa". The experiment's field land utilizations were cornfield and fallow farmland, with the fallow field later used for rotating winter wheat. The autumn daily characteristics of heat and water exchange evidently differed between the mesa cornfield and fallow, and the imbalance term of the surface energy was large. This is discussed in terms of sampling errors in the flux observations footprint; energy storage terms of soil and vegetation layers; contribution from air advections; and low and high frequency loss of turbulent fluxes and instruments bias. Comparison of energy components between the mesa cornfield and the lowland cornfield did not reveal any obvious difference. Inadequacies of the field observation equipment and experimental design emerged during the study, and some new research topics have emerged from this pilot experiment for future investigation.

  9. Surface Deformation Associated with Geothermal Fluids Extraction at the Cerro Prieto Geothermal Field, Baja California, Mexico Revealed by DInSAR Technique

    Science.gov (United States)

    Sarychikhina, O.; Glowacka, E.; Mojarro, J.

    2016-08-01

    The Differential Synthetic Aperture Radar Interferometry (DInSAR) is widely used for surface deformation detection and monitoring.In this paper, ERS-1/2, ENVISAT and RADARSAT-2 synthetic aperture radar (SAR) images acquired between 1993 and 2014 were processed to investigate the evolution of surface deformation at the Cerro Prieto geothermal field, Baja California, Mexico. The conventional DInSAR together with the interferogram stacking method was applied. Average LOS (line of sight) displacement velocity maps were generated for different periods: 1993 - 1997, 1998 - 2000, 2004, 2005, 2007, 2009, and 2012 - 2014, revealing that the area corresponding to Cerro Prieto basin presented the important surface deformation (mainly subsidence) during the entire time of investigation. The changes in the surface deformation pattern and rate were identified. These changes have a good correlation in time with the changes of production in the Cerro Prieto geothermal field.

  10. The Ahuachapan geothermal field, El Salvador: Exploitation model, performance predictions, economic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ripperda, M.; Bodvarsson, G.S.; Lippmann, M.J.; Witherspoon, P.A.; Goranson, C.

    1991-05-01

    The Earth Sciences Division of Lawrence Berkeley Laboratory (LBL) is conducting a reservoir evaluation study of the Ahuachapan geothermal field in El Salvador. This work is being performed in cooperation with the Comision Ejecutiva Hidroelectrica del Rio Lempa (CEL) and the Los Alamos National Laboratory (LANL) with funding from the US Agency for International Development (USAID). This report describes the work done during the second year of the study (FY89--90). The first year's report included (1) the development of geological and conceptual models of the field, (2) the evaluation of the reservoir's initial thermodynamic and chemical conditions and their changes during exploitation, (3) the evaluation of interference test data and the observed reservoir pressure decline and (4) the development of a natural state model for the field. In the present report the results of reservoir engineering studies to evaluate different production-injection scenarios for the Ahuachapan geothermal field are discussed. The purpose of the work was to evaluate possible reservoir management options to enhance as well as to maintain the productivity of the field during a 30-year period (1990--2020). The ultimate objective was to determine the feasibility of increasing the electrical power output at Ahuachapan from the current level of about 50 MW{sub e} to the total installed capacity of 95 MW{sub e}. 20 refs., 75 figs., 10 tabs.

  11. Exploration and development of Uenotai geothermal field, Akita prefecture, northeastern Japan. Uenotai chinetsu chitai no tansa to sono kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Naka, T. (Akita Geothermal Energy Co., Akita (Japan)); Okada, H. (Dowa Mining Co. Ltd., Tokyo (Japan))

    1992-08-30

    This paper describes exploration and development of the Uenotai geothermal field where a geothermal power plant is being build to start power generation scheduled for 1994. Geothermal reservoir beds at the Uenotai field are of fracture type. The beds consist not only of fracture zones generated from fault motions, but also autobrecciated lava structure, lithofacial boundaries including different lithofacies at lava bottom, intrusive rock circumference, and fault fracture zones crossing complexly with these formations, forming passages of geothermal fluids and the basis for heat convection. The heat source is thought to be the Quaternary magma source located deep under the upheaval area in Mt. Oyasu, where geothermal reservoir beds of hot water dominant type, steam dominant type, and high-temperature seam type exist. The produced hot water is of an alkaline NaCl type. The pre-Tertiary deposit in the Uenotai area under development would be the most important bed for the development, and geothermal reservoir beds of steam dominant type at 500 m below sea level or deeper are the target for the development. The scale of the development has been established under an assumption that it is most effective to produce steam at 232 t/h maintaining the well opening pressure at 9.5 KSCA to generate power at 27500kW. 18 refs., 16 figs., 8 tabs.

  12. Detailed microearthquake studies at the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Majer, E.L. (Lawrence Berkeley Lab., CA); McEvilly, T.V.

    1981-01-01

    There appears to be an increase in seismic activity within the Cerro Prieto production zone since early 1978. The microearthquake activity is now more or less constant at a rate of 2 to 3 events per day. The b-values within the field are significantly higher inside the production zone than are those for events on faults outside of the production region. The earthquakes seem to be controlled by the Hidalgo fault, although slight clustering was observed in the center of the main production region. The earthquakes within the production zone may reflect the reservoir dynamics associated with heat and mass withdrawal. Mechanisms such as volume change, thermal stresses and weakening of materials associated with boiling (i.e., phase changes, dissolution) may all be responsible for the increased seismic activity. Although a small reinjection program has started, the pressure drawdown conditions existing within the field would imply that increased pore pressure resulting from the injection activities is not responsible for the increased seismic activity.

  13. 3D Extended Logging for Geothermal Resources: Field Trials with the Geo-Bilt System

    Energy Technology Data Exchange (ETDEWEB)

    Mallan, R; Wilt, M; Kirkendall, B; Kasameyer, P

    2002-05-29

    Geo-BILT (Geothermal Borehole Induction Logging Tool) is an extended induction logging tool designed for 3D resistivity imaging around a single borehole. The tool was developed for deployment in high temperature geothermal wells under a joint program funded by the California Energy Commission, Electromagnetic Instruments (EMI) and the U.S. Department of Energy. EM1 was responsible for tool design and manufacture, and numerical modeling efforts were being addressed at Lawrence Livermore Laboratory (LLNL) and other contractors. The field deployment was done by EM1 and LLNL. The tool operates at frequencies from 2 to 42 kHz, and its design features a series of three-component magnetic sensors offset at 2 and 5 meters from a three-component magnetic source. The combined package makes it possible to do 3D resistivity imaging, deep into the formation, from a single well. The manufacture and testing of the tool was completed in spring of 2001, and the initial deployment of Geo-BILT occurred in May 2001 at the Lost Hills oil field in southern California at leases operated by Chevron USA. This site was chosen for the initial field test because of the favorable geological conditions and the availability of a number of wells suitable for tool deployment. The second deployment occurred in April 2002 at the Dixie Valley geothermal field, operated by Caithness Power LLC, in central Nevada. This constituted the first test in a high temperature environment. The Chevron site features a fiberglass-cased observation well in the vicinity of a water injector. The injected water, which is used for pressure maintenance and for secondary sweep of the heavy oil formation, has a much lower resistivity than the oil bearing formation. This, in addition to the non-uniform flow of this water, creates a 3D resistivity structure, which is analogous to conditions produced from flowing fractures adjacent to geothermal boreholes. Therefore, it is an excellent site for testing the 3D capability of

  14. Geoelectric studies on the east rift, Kilauea volcano, Hawaii Island. Geothermal resources exploration in Hawaii: Number 3

    Energy Technology Data Exchange (ETDEWEB)

    Keller, G.V.; Skokan, C.K.; Skokan, J.J.; Daniels, J.; Kauahikaua, J.P.; Klein, D.P.; Zablocki, C.J.

    1977-12-01

    Three geophysical research organizations, working together under the auspices of the Hawaii Geothermal Project, have used several electrical and electromagnetic exploration techniques on Kilauea volcano, Hawaii to assess its geothermal resources. This volume contains four papers detailing their methods and conclusions. Separate abstracts were prepared for each paper. (MHR)

  15. Guidebook to Geothermal Finance

    Energy Technology Data Exchange (ETDEWEB)

    Salmon, J. P.; Meurice, J.; Wobus, N.; Stern, F.; Duaime, M.

    2011-03-01

    This guidebook is intended to facilitate further investment in conventional geothermal projects in the United States. It includes a brief primer on geothermal technology and the most relevant policies related to geothermal project development. The trends in geothermal project finance are the focus of this tool, relying heavily on interviews with leaders in the field of geothermal project finance. Using the information provided, developers and investors may innovate in new ways, developing partnerships that match investors' risk tolerance with the capital requirements of geothermal projects in this dynamic and evolving marketplace.

  16. Application of differential magnetic sounding to the study of the Travale-Radicondoli geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    In 1980 and in 1982, the Laboratory Applied Geophysics of the C.N.R.S. attempted to establish by magnetic differential sounding a possible anomaly of conductivity, linked with the geothermal field of Travale-Radicondoli (Tuscany). Some 25 sites have been occupied along two profiles, one being located between Siena and Populonia, near Piombino, the other one between Siena and Cecina. An important anomaly of the transient magnetic field (some 15% of the normal field) was brought to light in 1980 between Gerfalco (in the S.W.) and Frosini (in the N.E.). It exactly covers the geothermal area of Travale. The direction of the telluric currents causing the anomaly is parallel to the magnetic meridian and their maximum depth is of some 2000 metres. The 1982 campaign has shown that in the North of Travale, anomalous currents move in the N.W.-S.W. direction or even completely E.-W. (in the S.W. of Volterra), and meet in the sea, round Livorno. One can give an interpretation of the phenomena as a whole, if one admits the presence of very conductive layers between Lardello and Travale. The currents which circulate parallel to the coast are channelled locally by this structure which could be closely linked up with the vapour field.

  17. Study of practical cycles for geothermal power plants. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Eskesen, J.H.

    1977-04-01

    A comparison is made of the performance and cost of geothermal power cycles designed specifically, utilizing existing technology, to exploit the high temperature, high salinity resource at Niland and the moderate temperature, moderately saline resource at East Mesa in California's Imperial Valley. Only two kinds of cycles are considered in the analysis. Both employ a dual flash arrangement and the liberated steam is either utilized directly in a condensing steam turbine or used to heat a secondary working fluid in a closed Rankine (binary) cycle. The performance of several organic fluids was investigated for the closed cycle and the most promising were selected for detailed analysis with the given resource conditions. Results show for the temperature range investigated that if the noncondensible gas content in the brine is low, a dual flash condensing steam turbine cycle is potentially better in terms of resource utilization than a dual flash binary cycle. (The reverse is shown to be true when the brine is utilized directly for heat exchange.) It is also shown that despite the higher resource temperature, the performance of the dual flash binary cycle at Niland is degraded appreciably by the high salinity and its output per unit of brine flow is almost 20 percent lower than that of the steam turbine cycle at East Mesa. Turbine designs were formulated and costs established for power plants having a nominal generating capacity of 50 MW. Three cycles were analyzed in detail. At East Mesa a steam turbine and a binary cycle were compared. At Niland only the binary cycle was analyzed since the high CO/sub 2/ content in the brine precludes the use of a steam turbine there. In each case only the power island equipment was considered and well costs and the cost of flash separators, steam scrubbers and piping to the power plant boundary were excluded from the estimate.

  18. Seismic Investigations of the Murci Geothermal Field (Southern Tuscany, Italy): Preliminary Results

    Science.gov (United States)

    Riedel, M.; Alexandrakis, C.; Buske, S.

    2013-12-01

    The Monte Amiata region in the Southern Tuscany, Central Italy, describes a volcanic complex with great significance in terms of the regional fresh water supply, mining and geothermal power generation. Mainly for the latter purpose, the volcanic area of Mt Amiata has been the subject of extensive geological and geophysical research (e.g. Dini et al., 2010 and references therein). The insights from these studies have led to successful geothermal production in the Mt Amiata region since the early 1960s (e.g. Batini et al., 2003). Today's most important reservoirs in this area are the Bagnore and the Piancastagnaio fields which are both operated by the company Enel Green Power. The work presented here deals with the Murci area, another potential reservoir located about 10 km southwest of the Mt Amiata volcanic complex. Therefore, in order to get a more detailed understanding of this area, five reflection seismic profiles were carried out. We have performed on three of them a preliminary depth-migrated images, through Kirchhoff prestack depth migration (KPSDM). The vital point of depth migration algorithms is the accuracy of the velocity model that is used for the backpropagation of the seismic data. Therefore, we derived a suitable 1D starting model from nearby well logs and VSP measurements. In order to remove the large topography effects along the profiles, we then utilized first-arrival tomography for each seismic line. For the following processing we incorporated these 2D tomographic results into our starting model which compensates for static effects and improves the resolution in the near-surface area. The velocity models were then used in the application of KPSDM to the seismic data for each profile, respectively. The resulting preliminary images show a zone of high seismic reflectivity, known as the 'K-horizon' (e.g. Brogi, 2008), and could improve its geological interpretation. These promising results encourage us to proceed with deeper migration velocity

  19. Rapid high temperature field test method for evaluation of geothermal calcite scale inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G.

    1982-08-01

    A test method is described which allows the rapid field testing of calcite scale inhibitors in high- temperature geothermal brines. Five commercial formulations, chosen on the basis of laboratory screening tests, were tested in brines with low total dissolved solids at ca 500 F. Four were found to be effective; of these, 2 were found to be capable of removing recently deposited scale. One chemical was tested in the full-flow brine line for 6 wks. It was shown to stop a severe surface scaling problem at the well's control valve, thus proving the viability of the rapid test method. (12 refs.)

  20. A tracer test at the Beowawe geothermal field, Nevada, using fluorescein and tinopal CBS

    Energy Technology Data Exchange (ETDEWEB)

    Rose, P.E.; Adams, M.C. [Univ. of Utah, Salt Lake City, UT (United States); Benoit, D. [Oxbow Power Services, Inc., Reno, NV (United States)

    1995-12-31

    An interwell tracer test using fluorescein and tinopal CBS was performed at the Beowawe geothermal field in north-central Nevada in order to assess the effects of recent changes to the injection strategy. Fluorescein return curves established injection-production flow patterns and verified that produced water is being reinjected into a region of the reservoir that is in excellent communication with the production wells. An analysis of the tinopal CBS return curves indicated that tinopal CBS was apparently strongly adsorbed onto the reservoir rock. The fluorescein return curves were used to estimate the overall (fractures and matrix) reservoir volume.

  1. Radon measurements at IC-09 well of Chingshui geothermal field (Taiwan): A case study

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y. [Department of Mineral and Petroleum Engineering, National Cheng Kung University, 1, University Ave., Tainan 701, Taiwan (China); Kuo, T., E-mail: mctkuobe@mail.ncku.edu.t [Department of Mineral and Petroleum Engineering, National Cheng Kung University, 1, University Ave., Tainan 701, Taiwan (China); Fan, K. [Department of Mineral and Petroleum Engineering, National Cheng Kung University, 1, University Ave., Tainan 701, Taiwan (China); Liang, H. [Exploration and Development Research Institute, CPC Corporation, Taiwan (China); Tsai, C. [Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan (China); Chiang, C. [Central Geological Survey, Ministry of Economic Affairs, Taipei, Taiwan (China); Su, C. [Department of Mineral and Petroleum Engineering, National Cheng Kung University, 1, University Ave., Tainan 701, Taiwan (China)

    2011-02-15

    Radon concentration was monitored during the flow tests of well IC-09 at the Chingshui geothermal field. The radon concentration was found to increase from 54 {+-} 29 to 983 {+-} 65 Bq/m{sup 3} as a step function of production time, or cumulative production. The observed radon behavior can be explained by a radial composite model with the carbonate scales deposited in the skin zone near the well. The radius of skin zone near well IC-09 can be estimated with radon data at about 20 m using a plug flow model. Monitoring natural radon during the well flow tests is a helpful tracer to diagnose the formation damage near the well.

  2. Gas equilibria in Cerro Prieto geothermal field, B.C., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Portugal, E.; Barragan, R.M.; Izquierdo, G. [Inst. de Investigaciones Electricas, Morelos (Mexico); Leon, J. de [Comision Federal de Electricidad, Mexicali B.C. (Mexico)

    2003-07-01

    Gas equlibria methods involving fischer-tropsch-pyrite-magnetite; and fischer-tropsch-pyrite-hematite-pyrite-magnetite reactions were used to evaluate reservoir temperature and a mass steam fraction in Cerro Prieto geothermal field. These approaches have been applied in some selected producing wells from four areas under exploitation. The results show good correlation for both equilibria methods; however fischer-tropsch; pyrite-magnetite reactions provide the best estimation of the physical reservoir parameters. The main processes found for Cerro Prieto IV area are lateral vapor contribution and the inflow of hotter and deeper fluid with high liquid saturation. (orig.)

  3. Trace element hydrochemistry indicating water contamination in and around the Yangbajing geothermal field, Tibet, China.

    Science.gov (United States)

    Guo, Qinghai; Wang, Yanxin

    2009-10-01

    Thirty-eight water samples were collected at Yangbajing to investigate the water contamination resulting from natural geothermal water discharge and anthropogenic geothermal wastewater drainage. The results indicate that snow or snow melting waters, Yangbajing River waters and cold groundwaters are free from geothermal water-related contamination, whereas Zangbo river waters are contaminated by geothermal wastewaters. Moreover, there may exist geothermal springs under the riverbed of a tributary stream of Zangbo River as shown by its Cd, Li, Mo and Pb concentrations. The efforts made in this study show trace element hydrochemistry can well indicate water quality degradation related to geothermal water exploitation.

  4. FINITE ELEMENT NUMERICAL SIMULATION FOR THE HYDRODYNAMIC FIELD EVOLUTION OF GEOTHERMAL WATER IN THE NANWENQUAN ANTICLINE IN CHONGQING IN CHINA

    Institute of Scientific and Technical Information of China (English)

    LUO Yun-ju; LIU Dong-yan; LIU Xin-rong

    2006-01-01

    The Nanwenquan (South Hot Spring) and Xiao quan (Small Hot Spring) in the Nanwenquan anticline are well-known attraction for their geothermal water, but currently, the two natural hot springs have hot flow naturally. In order to protect the geothermal water resource, the evolution of hydrodynamic field must be researched for the causation of the hydrodynamic field destroyed. The finite element numerical simulation was adopted and quantitative study on the geothermal water hydrodynamic field. The finite element model was set up to simulate the research sites, the simulated water level was compared with the actual water level, the feasibility of this model was proved when the simulated water level is approximate to actual one, and an applicable finite element model was obtained. The finite element model was used to simulate the evolution of the hydrodynamic field. This paper supplies a basis to exploit adequately and protect effectively the geothermal water resource, at the same time it is proved feasible in practice to apply finite element numerical simulation to quantitative study of the geothermal water.

  5. Improved Detection of Microearthquakes in Geothermal Areas - Applying Empirical Matched Field Processing to Traditional and EGS sites

    Science.gov (United States)

    Templeton, D. C.; Wang, J.; Harris, D. B.

    2012-12-01

    The aim of this project is to increase the amount of information that can be extracted from seismic data collected in EGS or traditional geothermal areas. To accomplish our objective, we develop a seismic imaging technique that can map seismicity from discrete microearthquake sources using the Matched Field Processing (MFP) method. We use data from the Salton Sea geothermal field available from the Southern California Earthquake Data Center. Data between November 2009 and December 2010 was downloaded off the web and 231 high-quality master events were identified from the online catalog. This time period included two robust earthquake swarms. We created matched field steering vector calibrations for 7 three-component stations within the Salton Sea Geothermal Field. The official earthquake catalog identified 1536 events. When we applied the empirical MFP technique to the same data, we identified 5357 events. We then compare the results from this traditional geothermal area with results obtained from an Engineered Geothermal System (EGS) site. Finally, we compare the number of events in the improved earthquake catalogs with available fluid injection data. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  6. Feasibility study report for the Imperial Valley Ethanol Refinery: a 14. 9-million-gallon-per-year ethanol synfuel refinery utilizing geothermal energy

    Energy Technology Data Exchange (ETDEWEB)

    1981-03-01

    The construction and operation of a 14,980,000 gallon per year fuel ethanol from grain refinery in the Imperial Valley of California is proposed. The Imperial Valley Ethanol Refinery (refinery) will use hot geothermal fluid from geothermal resources at the East Mesa area as the source of process energy. In order to evaluate the economic viability of the proposed Project, exhaustive engineering, cost analysis, and financial studies have been undertaken. This report presents the results of feasibility studies undertaken in geothermal resource, engineering, marketing financing, management, environment, and permits and approvals. The conclusion of these studies is that the Project is economically viable. US Alcohol Fuels is proceeding with its plans to construct and operate the Refinery.

  7. Identification of Surface Manifestation at Geothermal Field Using SAR Dual Orbit Data

    Science.gov (United States)

    Akbari, Dinul; Saepuloh, Asep

    2016-09-01

    The Wayang -Windu Geothermal Field located in West Java, Indonesia is a geothermal field under tropical zone which is identified by high precipitation, dense vegetation, and extensive weathering/alteration. The clouds due to high precipitation and vegetation conditions on the tropical zone inhibit the identification of surface manifestation using optical remote sensing techniques. In this paper, we reduced these inhibiting factors using microwave remote sensing techniques termed as Synthetic Aperture Radar (SAR). The SAR dual orbits were used to observe the targets on the surface by minimizing the effects from the clouds and dense vegetation cover. This study is aimed to identify surface manifestation based on Geo morphologic and Structural Features (GSF) of the SAR in Ascending and Descending orbits. The Linear Features Density of SAR (lifedSAR) method was applied to quantify the linear features of the ground surface and served as basis of surface manifestation identification. Based on the lifedSAR and field observations, the surface manifestations could be detected succesfully at Wayang and Cibolang craters with density about 45%. The soil measurements were used validate the result and to interpret the correlation between LFD and surface manifestations.

  8. A review of the microbiology of the Rehai geothermal field in Tengchong, Yunnan Province, China

    Directory of Open Access Journals (Sweden)

    Brian P. Hedlund

    2012-05-01

    Full Text Available The Rehai Geothermal Field, located in Tengchong County, in central-western Yunnan Province, is the largest and most intensively studied geothermal field in China. A wide physicochemical diversity of springs (ambient to ∼97 °C; pH from ≤1.8 to ≥9.3 provides a multitude of niches for extremophilic microorganisms. A variety of studies have focused on the cultivation, identification, basic physiology, taxonomy, and biotechnological potential of thermophilic microorganisms from Rehai. Thermophilic bacteria isolated from Rehai belong to the phyla Firmicutes and Deinococcus-Thermus. Firmicutes include neutrophilic or alkaliphilic Anoxybacillus, Bacillus, Caldalkalibacillus, Caldanaerobacter, Laceyella, and Geobacillus, as well as thermoacidophilic Alicyclobacillus and Sulfobacillus. Isolates from the Deinococcus-Thermus phylum include several Meiothermus and Thermus species. Many of these bacteria synthesize thermostable polymer-degrading enzymes that may be useful for biotechnology. The thermoacidophilic archaea Acidianus, Metallosphaera, and Sulfolobus have also been isolated and studied. A few studies have reported the isolation of thermophilic viruses belonging to Siphoviridae (TTSP4 and TTSP10 and Fuselloviridae (STSV1 infecting Thermus spp. and Sulfolobus spp., respectively. More recently, cultivation-independent studies using 16S rRNA gene sequences, shotgun metagenomics, or “functional gene” sequences have revealed a much broader diversity of microorganisms than represented in culture. Studies of the gene and mRNA encoding the large subunit of the ammonia monooxygenase (amoA of ammonia-oxidizing Archaea (AOA and the tetraether lipid crenarchaeol, a potential biomarker for AOA, suggest a wide diversity, but possibly low abundance, of thermophilic AOA in Rehai. Finally, we introduce the Tengchong Partnerships in International Research and Education (PIRE project, an international collaboration between Chinese and U.S. scientists with

  9. Coupled thermo-hydro-mechanical modeling of heat extraction from the Tattapani geothermal field, India

    Science.gov (United States)

    Nand Pandey, Sachchida; Vishal, Vikram

    2017-04-01

    Modeling of coupled thermo-hydro-mechanical processes in enhanced geothermal systems is presented using the finite element method of modeling for a 3-D domain. The reservoir consists of a single horizontal fracture surrounded by low permeable rock matrix. The flow is imposed on a fracture plane, consisting of a doublet system. The reservoir rock mechanical properties were taken from the field data of the Tattapani geothermal field, India. We investigate the effects of injection temperature and mass flow rate on the energy output. The results indicate that temperature and pressure changes within the reservoirs occur due to injection of cold water. The temperature drop and fluid overpressure inside the reservoirs/fracture affect the transport properties of the fracture. The spatial-temporal variations of fracture aperture inside the reservoir greatly impact the thermal drawdown and therefore net energy output. The results showed that maximum aperture evolution occurs near the injection zone than the production zone. The fracture aperture evolution is a result of combined effects of thermal stress and fluid overpressure inside the fracture. The fracture opening reduces the injection pressure required to circulate the fixed volume of water. The effects of the injection temperature on heat extraction were also analyzed under different reservoir formations. The results indicate that reservoir permeability plays a significant role on heat extraction, highlighting the important effect of water losses. For each factor, it is concluded that thermal breakthrough primarily depends on injection temperate, mass flow rate, reservoir permeability and well distances. The results of this study can help in choosing the operational parameters for successful operation of geothermal system. The study will also be helpful to optimize the EGS performance under varying reservoir conditions.

  10. Numerical Modelling and Geological Interpretation of Geothermal Fields in Black Sea

    Science.gov (United States)

    Kostyanev, Simeon; Trapov, Georgi; Dimovski, Stefan; Vasilev, Atanas; Stoyanov, Velislav; Kostadinov, Evgeni

    2013-04-01

    A numerical solution to the thermal conductivity equation was carried out along three profiles; the Varna-Sukhumi profile and two transverse profiles. The purpose of this paper is a more detailed study of the distribution in depth of the thermal field in the light of the latest geological and geophysical data concerning the age and structure of the sedimentary rocks and the Black Sea basement. Specified seismic and tomographic data about the sedimentary formation and the region basement were obtained and employed in order to precise the results obtained from the previous studies. Calculations were carried out along a geological profile using real properties of sedimentary rocks and basement and they have shown that the regional variation of temperature along the Moho plane varies from 420 to 754° ?. The heat flow along the same plane varies from 15-20 t? 29-41 mW /m2. The part of the heat flow that is caused by radiogenic sources amounts to 17-30 mW/m2. The modelling results are presented as sections that illustrate the distribution of temperature and heat flow in depth. This article is initiated by the fact that between 1st January 2009 and 12th December 2011, Project # 226592, entitled "UP-GRADE BLACK SEA SCIENTIFIC NETWORK", was worked out as part of the Seventh Framework Program (FP7). A team from the University of Mining and Geology, Sofia, took part in the project developing a geothermal database for the Black Sea basin. Part of the data was employed for the modeling of then geothermal field along the Varna-Sukhumi Profile. A catalogue is being prepared that is going to comprise all geothermal data of the Black Sea that are available so far and that amount more than 750 at present. The authors wish to thank the Project Management for the provided opportunity to work on this problem. The numerical modelling the analysis and interpretation of geothermal data will contribute to the study of the geological evolution of the lithosphere of the Black Sea depression.

  11. Mantle-derived CO2 in Hot Springs of the Rehai Geothermal Field,Tengchong, China

    Institute of Scientific and Technical Information of China (English)

    REN Jianguo; WANG Xianbin; OUYANG Ziyuan

    2005-01-01

    Gas concentrations and isotopic compositions of He and CO2 were determined on free gas samples from ten hot springs of the Rehai geothermal field, Tengchong, China. The results showed that hot-spring CO2 gas, together with He,was derived mainly from the mantle, indicating the accumulation of mantle-derived volatiles beneath the survey area. The δ13C values of CO2, higher than those of the typical mantle-derived carbon and the isotopic composition of hot-spring-free CO2 in unequilibrium with dissolved CO2, are recognized only in the Rehai geothermal field, suggesting that there seems to be a still-degassing magmatic intrusion at depths, which provides mantle-derived volatiles to the hydrothermal system above. The accumulation of those volatiles has probably played an important role in triggering earthquakes in this region.In addition, the isotopic characteristics of He and C also indicate that the magmatic intrusion seems to have been derived from the MORB source, and could be contaminated by crustal materials during its upwelling through the continental crust.

  12. Repetitive precision gravity studies at the Cerro Prieto and Heber geothermal fields

    Science.gov (United States)

    Grannell, R. B.

    1982-09-01

    To study subsidence and mass removal, a precise gravity network was established on 60 permanent monuments in the Cerro Prieto geothermal field in early 1978, and repeated annually through early 1981; the survey was tied to two bedrock sites outside the limits of the current production zone. The looping technique of station occupation was utilized, in which occupation of the base was followed by occupation of several stations, followed by a return to the base. Use of two LaCoste and Romberg gravity meters, and replication of values within loops as well as entire loops, enhanced precision such that the median standard deviations of the base-to-station differences, reduced to observed gravity values, ranged from 7 to 15 microgals for individual surveys. The smaller values were obtained as field and data reduction techniques were improved and experience was gained. A similar survey was initiated in the Heber area just north of the Mexican border in early 1980. It too was established on permanent monuments, was tied to bedrock stations outside the geothermal area, and used multiple repetitions of values with two meters to achieve high precision.

  13. Preliminary study in phase tensor analysis of magnetotelluric data: Case study of "X" geothermal field data

    Science.gov (United States)

    Dewi, Mayvita; Widodo, Raharjo, Imam B.

    2017-07-01

    Magnetotelluric method is commonly used for geothermal investigation due to its ability to image changes in resistivity distribution from the greater depth. However, the field magnetotelluric data is affected by distribution of geometry and conductivity heterogeneity near the surface. It can distort the magnetotelluric data response. In order to resolve the problem, the phase tensor analysis has been conducted in this paper. Phase tensor analysis has been implemented to "X" geothermal field data. The results show that the dimensionality of the area is closed to 2D from the frequency of 0.5 to 10-2 Hz, and is 3-D for lower frequency. While, the resistivity analysis has shown that the strike direction of the measurement area is N0°E - N18°E, with 90° ambiguity, or N90°E-N108°E. The resistivity increases with the depth and a conductive layer detected on the southern part of the study area.

  14. Icelandic basaltic geothermal field: A natural analog for nuclear waste isolation in basalt

    Energy Technology Data Exchange (ETDEWEB)

    Ulmer, G.C.; Grandstaff, D.E. (Temple Univ., Philadelphia, PA (USA). Dept. of Geology)

    1984-11-21

    Analog studies of Icelandic geothermal fields have shown that the design of nuclear waste repositories in basalt can benefit by comparison to the data base already available from the development of these geothermal fields. A high degree of similarity exists between these two systems: their petrology, groundwater geochemistry, mineral solubilities, hydrologic parameters, temperature ranges, water-rock redox equilibria, hydrothermal pH values, and secondary mineralogies all show considerable overlap in the range of values. The experimentally-simulated hydrothermal studies of the basaltic nuclear waste repository rocks have, at this time, produced a data base that receives a strong confirmation from the Icelandic analog. Furthermore, the Icelandic analog should eventually be employed to extrapolate into higher and lower temperatures, into longer time-base chemical comparisons, and into more realistic mineral deposition studies, than have been possible in the laboratory evaluations of the nuclear waste repository designs. This eventual use of the Icelandic analog will require cooperative work with the Icelandic Geological Survey. 46 refs., 4 figs., 2 tabs.

  15. Geothermal Resource Exploration by Stream pH Mapping in Mutsu Hiuchi Dake Volcano, Japan

    Directory of Open Access Journals (Sweden)

    Yota Suzuki

    2017-07-01

    Full Text Available Although pH measurements of hot spring water are taken in conventional geothermal resource research, previous studies have seldom created pH distribution maps of stream and spring waters for an entire geothermal field as a technique for geothermal exploration. In this study, a pH distribution map was created by measuring stream and spring water pH at 75 sites in the Mutsu Hiuchi Dake geothermal field, Japan. Areas of abnormally high pH were detected in midstream sections of the Ohaka and Koaka rivers; these matched the location of the Mutsu Hiuchi Dake East Slope Fault, which is believed to have formed a geothermal reservoir. The abnormally high pH zone is attributed to the trapping of rising volcanic gases in a mature geothermal reservoir with neutral geothermal water. This causes the gas to dissolve and prevents it from reaching the surface. Thus, the mapping of stream water pH distribution in a geothermal field could provide a new and effective method for estimating the locations of geothermal reservoirs. As the proposed method does not require laboratory analysis, and is more temporally and economically efficient than conventional methods, it might help to promote geothermal development in inaccessible and remote regions.

  16. Addendum to material selection guidelines for geothermal energy-utilization systems. Part I. Extension of the field experience data base. Part II. Proceedings of the geothermal engineering and materials (GEM) program conference (San Diego, CA, 6-8 October 1982)

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C.S.; Ellis, P.F. II

    1983-05-01

    The extension of the field experience data base includes the following: key corrosive species, updated field experiences, corrosion of secondary loop components or geothermal binary power plants, and suitability of conventional water-source heat pump evaporator materials for geothermal heat pump service. Twenty-four conference papers are included. Three were abstracted previously for EDB. Separate abstracts were prepared for twenty-one. (MHR)

  17. Reservoir Changes Derived from Seismic Observations at The Geysers Geothermal Field, CA, USA

    Science.gov (United States)

    Gritto, R.; Jarpre, S.

    2012-04-01

    Induced seismicity associated with the exploitation of geothermal fields is used as a tool to characterize and delineate changes associated with injection and production of fluids from the reservoir. At the same time public concern of felt seismicity has led to objections against the operation of geothermal reservoirs in close proximity to population centers. Production at the EGS sites in Basel (Switzerland) was stopped after renewed seismicity caused concern and objection from the public in the city. Operations in other geothermal reservoirs had to be scaled back or interrupted due to an unexpected increase in seismicity (Soultz-sous-forêt, France, Berlín, El Salvador). As a consequence of these concerns and in order to optimize the use of induced seismicity for reservoir engineering purposes, it becomes imperative to understand the relationship between seismic events and stress changes in the reservoir. We will address seismicity trends at The Geysers Geothermal Reservoir, CA USA, to understand the role of historical seismicity associated with past injection of water and/or production of steam. Our analysis makes use of a comprehensive database of earthquakes and associated phase arrivals from 2004 to 2011. A high-precision sub-set of the earthquake data was selected to analyze temporal changes in seismic velocities and Vp/Vs-ratio throughout the whole reservoir. We find relatively low Vp/Vs values in 2004 suggestive of a vapor dominated reservoir. With passing time, however, the observed temporal increase in Vp/Vs, coupled with a decrease in P- and S-wave velocities suggests the presence of fluid-filled fractured rock. Considering the start of a continuous water injection project in 2004, it can be concluded that the fluid saturation of the reservoir has successfully recovered. Preliminary results of 3-D velocity inversions of seismic data appear to corroborate earlier findings that the lowest Vp/Vs estimates are observed in the center of the reservoir

  18. Archaeology in the Kilauea East Rift Zone: Part 2, A preliminary sample survey, Kapoho, Kamaili and Kilauea geothermal subzones, Puna District, Hawaii island

    Energy Technology Data Exchange (ETDEWEB)

    Sweeney, M.T.K.; Burtchard, G.C. [International Archaeological Research Inst., Inc., Honolulu, HI (United States)

    1995-05-01

    This report describes a preliminary sample inventory and offers an initial evaluation of settlement and land-use patterns for the Geothermal Resources Subzones (GRS) area, located in Puna District on the island of Hawaii. The report is the second of a two part project dealing with archaeology of the Puna GRS area -- or more generally, the Kilauea East Rift Zone. In the first phase of the project, a long-term land-use model and inventory research design was developed for the GRS area and Puna District generally. That report is available under separate cover as Archaeology in the Kilauea East Rift Zone, Part I: Land-Use Model and Research Design. The present report gives results of a limited cultural resource survey built on research design recommendations. It offers a preliminary evaluation of modeled land-use expectations and offers recommendations for continuing research into Puna`s rich cultural heritage. The present survey was conducted under the auspices of the United States Department of Energy, and subcontracted to International Archaeological Research Institute, Inc. (IARII) by Martin Marietta Energy Systems, Inc. The purpose of the archaeological work is to contribute toward the preparation of an environmental impact statement by identifying cultural materials which could be impacted through completion of the proposed Hawaii Geothermal Project.

  19. Pre-exploitation state of the Ahuachapán geothermal field, El Salvador

    Science.gov (United States)

    Aunzo, Z.; Laky, C.; Steingrimsson, B.; Bodvarsson, G.S.; Lippmann, M.J.; Truesdell, A.H.; Escobar, C.; Quintanilla, A.; Cuellar, G.

    1991-01-01

    The lithology and structural features of the Ahuachapán geothermal area and their impact on the movement of cold and hot fluids within the system are described, as well as the development and evaluation of the natural state model of the field. Four major lithologic units are present in Ahuachapán and three major aquifers have been identified; flow patterns and zones of fluid mixing were located on the basis of temperature and geochemical data from wells and surface manifestations. Geologic structures control the heat and fluid recharge and the flow within the reservoir. Modeling studies suggest, in agreement with field data, an overall average transmissivity of 25–35 darcy-meters, and indicate that the system is recharged by waters with temperatures greater than 250°C. The total thermal throughflow for the Ahuachapán reservoir in the unexploited state is estimated to be about 250 MWt.

  20. Hydrothermal Alteration in Submarine Basaltic Rocks from the Reykjanes Geothermal Field, Iceland. (Invited)

    Science.gov (United States)

    Zierenberg, R. A.; Schiffman, P.; Fowler, A. P.; Marks, N.; Fridleifsson, G.; Elders, W. A.

    2013-12-01

    The Iceland Deep Drilling Project (IDDP) is preparing to drill to 4-5 km in the Reykjanes Geothermal Field to sample geothermal fluids at supercritical temperature and pressure for power generation. The Reykjanes geothermal field is the on-land extension of the Reykjanes Ridge spreading center. The upper 1-2 kilometers drilled at Reykjanes are submarine basalts and basaltic sediments, hyalloclastites, and breccias, with an increasing proportion of basaltic intrusive rocks below 2 km depth. Geothermal fluids are evolved seawater with a composition similar to mid-ocean ridge hydrothermal systems. Zn- and Cu-rich sulfide scale, locally enriched in Au and Ag, are deposited in production pipes. The sulfide deposits are compositionally and isotopically similar to seafloor massive sulfides. In anticipation of deeper drilling, we have investigated the mineralogy and geochemistry of drill cuttings from a 3 km deep well (RN-17). The depth zoning of alteration minerals is similar to that described from other Icelandic geothermal fields, and is comparable to observed seafloor metamorphic gradients in ODP drill holes and ophiolites. Chlorite-epidote alteration occurs at depths >400 m and passes downhole through epidote-actinolite alteration and into amphibole facies (hornblende-calcic plagioclase) alteration below 2.5 km. Local zones of high temperature (>800°C), granoblastic-textured, pyroxene hornfels, are interpreted to form by contact metamorphism during dike/sill emplacement. Similar granoblasically altered basalts were recovered from the base of the sheeted dikes in IODP Hole 1256D. Downhole compositional variations of drill cuttings, collected every 50 m, suggest that rocks below ~ 2 km are little altered. Whole-rock oxygen isotope profiles are consistent with low water/rock ratios, but suggest that early stages of hydrothermal alteration included meteoric water-derived fluids. Strontium isotope profiles indicate more extensive exchange with seawater-derived fluids

  1. Full Moment Tensor Analysis Using First Motion Data at The Geysers Geothermal Field

    Science.gov (United States)

    Boyd, O.; Dreger, D. S.; Lai, V. H.; Gritto, R.

    2012-12-01

    Seismicity associated with geothermal energy production at The Geysers Geothermal Field in northern California has been increasing during the last forty years. We investigate source models of over fifty earthquakes with magnitudes ranging from Mw 3.5 up to Mw 4.5. We invert three-component, complete waveform data from broadband stations of the Berkeley Digital Seismic Network, the Northern California Seismic Network and the USA Array deployment (2005-2007) for the complete, six-element moment tensor. Some solutions are double-couple while others have substantial non-double-couple components. To assess the stability and significance of non-double-couple components, we use a suite of diagnostic tools including the F-test, Jackknife test, bootstrap and network sensitivity solution (NSS). The full moment tensor solutions of the studied events tend to plot in the upper half of the Hudson source type diagram where the fundamental source types include +CLVD, +LVD, tensile-crack, DC and explosion. Using the F-test to compare the goodness-of-fit values between the full and deviatoric moment tensor solutions, most of the full moment tensor solutions do not show a statistically significant improvement in fit over the deviatoric solutions. Because a small isotropic component may not significantly improve the fit, we include first motion polarity data to better constrain the full moment tensor solutions.

  2. Estimation of deepwater temperature and hydrogeochemistry of springs in the Takab geothermal field, West Azerbaijan, Iran.

    Science.gov (United States)

    Sharifi, Reza; Moore, Farid; Mohammadi, Zargham; Keshavarzi, Behnam

    2016-01-01

    Chemical analyses of water samples from 19 hot and cold springs are used to characterize Takab geothermal field, west of Iran. The springs are divided into two main groups based on temperature, host rock, total dissolved solids (TDS), and major and minor elements. TDS, electrical conductivity (EC), Cl(-), and SO4 (2-) concentrations of hot springs are all higher than in cold springs. Higher TDS in hot springs probably reflect longer circulation and residence time. The high Si, B, and Sr contents in thermal waters are probably the result of extended water-rock interaction and reflect flow paths and residence time. Binary, ternary, and Giggenbach diagrams were used to understand the deeper mixing conditions and locations of springs in the model system. It is believed that the springs are heated either by mixing of deep geothermal fluid with cold groundwater or low conductive heat flow. Mixing ratios are evaluated using Cl, Na, and B concentrations and a mass balance approach. Calculated quartz and chalcedony geothermometer give lower reservoir temperatures than cation geothermometers. The silica-enthalpy mixing model predicts a subsurface reservoir temperature between 62 and 90 °C. The δ(18)O and δD (δ(2)H) are used to trace and determine the origin and movement of water. Both hot and cold waters plot close to the local meteoric line, indicating local meteoric origin.

  3. A large and complete Jurassic geothermal field at Claudia, Deseado Massif, Santa Cruz, Argentina

    Science.gov (United States)

    Guido, Diego M.; Campbell, Kathleen A.

    2014-04-01

    Late Jurassic geothermal deposits at Claudia, Argentinean Patagonia, are among the largest (40 km2) and most varied in the Deseado Massif, a 60,000 km2 volcanic province hosting precious metals (Au, Ag) mineralization generated during diffuse back arc spreading and opening of the South Atlantic Ocean. Both siliceous sinter and travertine occur in the same stratigraphic sequence. Deposits range from those interpreted as fluvially reworked hydrothermal silica gels, to extensive apron terraces, to a clustering of high-temperature subaerial vent mounds. Paleoenvironmentally diagnostic textures of sinters include wavy laminated, bubble mat and nodular fabrics, and for travertines comprise fossil terracette rims, wavy laminated, bubble mat, spherulitic, oncoidal, and peloidal fabrics. Of special note is the presence of relatively large (to 25 cm high), inferred subaqueous "Conophyton" structures in travertines, which serve as analogs for some Precambrian stromatolites and imply the presence of relatively deep pools maintained by voluminous spring discharges. The Claudia geothermal field is geographically and geologically linked to the Cerro Vanguardia epithermal project (total resource of ~ 7.8 million ounces Au equivalent) via proximity, similar veins, and structural linkages, making it an especially large and relevant prospect for the region. The combined Claudia-Cerro Vanguardia hydrothermal system likely represents a fortuitous alignment of focused fluid flow and structure conducive to forming a giant epithermal ore deposit, with respect to size, ore concentration and potentially duration, in the Late Jurassic of Patagonia.

  4. Radon and thoron analysis of soil gas survey case study of Rajabasa geothermal field

    Science.gov (United States)

    Haerudin, Nandi; Wahyudi, Suryanto, Wiwit

    2013-09-01

    Radon and Thoron concentration of soil gas was measured by Scintrex Radon detector RDA 200 in the Rajabasa geothermal field, South Lampung regency, Indonesia. This study is aimed todeterminethe buried fault zoneunder theoverburdenlayer. The survey areacovers three geothermal manifestations in the southern part of Rajabasageothermalfield. The result indicates fault system trending SW-NE (N 60° E) and SSW-NNE (N 8° E). The contour map of Radon concentration performed high value in the three manifestations which was included survey area; those are 123 cpm in Gunung Botak hot spring, 145 cpm in Kunjir fumarole and 382 cpm about 300 m from Bulakan (Way Belerang) fumarole. Three manifestations were connected by two fault. The first fault passed begin from Gunung Botak directed to Kunjir and the other across the first fault from SSW to Bulakan. The contour map of Radon and Thoron ratio indicated that the second fault system is not only indicate the presence of the fault/fracture zones but also show the extension of the faults/fractures from the depth to the surface.

  5. Geologic characteristics of a portion of the Salton Sea geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Tewhey, J.D.

    1977-04-25

    The examination of drill cuttings and core samples from the Magmamax Nos. 2 and 3 and Woolsey No. 1 wells indicate that the sequence of sedimentary rocks in the Salton Sea geothermal field from the surface to below 4000 ft can be divided into three categories: cap rock, unaltered reservoir rocks, and hydrothermally altered reservoir rocks. The cap rock extends from the surface to a depth of approximately 1100 ft in all three wells. There is evidence to suggest that the cap rock has undergone self-sealing through time as a result of the circulation of hot brine through the rocks. Essentially unaltered reservoir rocks extend from a depth of 1100 ft to approximately 3000 ft. The mineralogical and textural changes that occur at depth can be attributed to the process of hydrothermal alteration. Alteration has occurred in a chemically open system and the important variables in the alteration scheme have been temperature, permeability, brine composition, and rock composition. The transition from unaltered to altered reservoir rocks is marked by the replacement of calcite by epidote. The first appearance of epidote correlates reasonably well with the top of the alteration zone as determined in other studies by electric log analysis. Biotite and chlorite, potential indicators of alteration zones, are considered to be of detrital origin rather than hydrothermal origin. The primary effect of hydrothermal alteration on the reservoir rocks in the Salton Sea geothermal field has been the reduction of porosity and permeability with depth. Petrographic analysis indicates that porosity and permeability in the field is enhanced by the presence of fractures in shales. The geologic picture that emerges from spontaneous potential (SP) log correlation is that of a structural basin whose axis lies to the northwest of Magmamax No. 2. The data suggest that unaltered reservoir rocks on the periphery of the field offer good production possibilities.

  6. Geothermal Resources in Spain; Recurssos geothermicos en Espana

    Energy Technology Data Exchange (ETDEWEB)

    Garcia de la Noceda Marquez, C.

    2009-07-01

    A general view on the geothermal resources is presented and the basic concepts of geothermal fields and their classification, the different possibilities of geothermal energy utilization as well as a general panoramic of geothermal energy in Spain. (Author) 6 refs.

  7. Geothermal handbook

    Science.gov (United States)

    1976-01-01

    The Bureau of Land Management offered over 400,000 hectares (one million acres) for geothermal exploration and development in 1975, and figure is expected to double this year. The Energy Research and Development Administration hopes for 10-15,000 megawatts of geothermal energy by 1985, which would require, leasing over 16.3 million hectares (37 million acres) of land, at least half of which is federal land. Since there is an 8 to 8-1/2 year time laf between initial exploration and full field development, there would have to be a ten-fold increase in the amount of federal land leased within the next three years. Seventy percent of geothermal potential, 22.3 million hectares (55 million acres), is on federal lands in the west. The implication for the Service are enormous and the problems immediate. Geothermal resource are so widespread they are found to some extent in most biomes and ecosystems in the western United States. In most cases exploitation and production of geothermal resources can be made compatible with fish and wildlife management without damage, if probable impacts are clearly understood and provided for before damage has unwittingly been allowed to occur. Planning for site suitability and concern with specific operating techniques are crucial factors. There will be opportunities for enhancement: during exploration and testing many shallow groundwater bodies may be penetrated which might be developed for wildlife use. Construction equipment and materials needed for enhancement projects will be available in areas heretofore considered remote projects will be available in areas heretofore considered remote by land managers. A comprehensive knowledge of geothermal development is necessary to avoid dangers and seize opportunities. This handbook is intended to serve as a working tool in the field. It anticipated where geothermal resource development will occur in the western United States in the near future. A set of environmental assessment procedures are

  8. Recover Act. Verification of Geothermal Tracer Methods in Highly Constrained Field Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Matthew W. [California State University, Long Beach, CA (United States)

    2014-05-16

    The prediction of the geothermal system efficiency is strong linked to the character of the flow system that connects injector and producer wells. If water flow develops channels or “short circuiting” between injection and extraction wells thermal sweep is poor and much of the reservoir is left untapped. The purpose of this project was to understand how channelized flow develops in fracture geothermal reservoirs and how it can be measured in the field. We explored two methods of assessing channelization: hydraulic connectivity tests and tracer tests. These methods were tested at a field site using two verification methods: ground penetrating radar (GPR) images of saline tracer and heat transfer measurements using distributed temperature sensing (DTS). The field site for these studies was the Altona Flat Fractured Rock Research Site located in northeastern New York State. Altona Flat Rock is an experimental site considered a geologic analog for some geothermal reservoirs given its low matrix porosity. Because soil overburden is thin, it provided unique access to saturated bedrock fractures and the ability image using GPR which does not effectively penetrate most soils. Five boreholes were drilled in a “five spot” pattern covering 100 m2 and hydraulically isolated in a single bedding plane fracture. This simple system allowed a complete characterization of the fracture. Nine small diameter boreholes were drilled from the surface to just above the fracture to allow the measurement of heat transfer between the fracture and the rock matrix. The focus of the hydraulic investigation was periodic hydraulic testing. In such tests, rather than pumping or injection in a well at a constant rate, flow is varied to produce an oscillating pressure signal. This pressure signal is sensed in other wells and the attenuation and phase lag between the source and receptor is an indication of hydraulic connection. We found that these tests were much more effective than constant

  9. Recover Act. Verification of Geothermal Tracer Methods in Highly Constrained Field Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Matthew W. [California State University, Long Beach, CA (United States)

    2014-05-16

    The prediction of the geothermal system efficiency is strong linked to the character of the flow system that connects injector and producer wells. If water flow develops channels or “short circuiting” between injection and extraction wells thermal sweep is poor and much of the reservoir is left untapped. The purpose of this project was to understand how channelized flow develops in fracture geothermal reservoirs and how it can be measured in the field. We explored two methods of assessing channelization: hydraulic connectivity tests and tracer tests. These methods were tested at a field site using two verification methods: ground penetrating radar (GPR) images of saline tracer and heat transfer measurements using distributed temperature sensing (DTS). The field site for these studies was the Altona Flat Fractured Rock Research Site located in northeastern New York State. Altona Flat Rock is an experimental site considered a geologic analog for some geothermal reservoirs given its low matrix porosity. Because soil overburden is thin, it provided unique access to saturated bedrock fractures and the ability image using GPR which does not effectively penetrate most soils. Five boreholes were drilled in a “five spot” pattern covering 100 m2 and hydraulically isolated in a single bedding plane fracture. This simple system allowed a complete characterization of the fracture. Nine small diameter boreholes were drilled from the surface to just above the fracture to allow the measurement of heat transfer between the fracture and the rock matrix. The focus of the hydraulic investigation was periodic hydraulic testing. In such tests, rather than pumping or injection in a well at a constant rate, flow is varied to produce an oscillating pressure signal. This pressure signal is sensed in other wells and the attenuation and phase lag between the source and receptor is an indication of hydraulic connection. We found that these tests were much more effective than constant

  10. Geothermal development. Semi-annual report, October 1, 1980-March 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    1981-03-31

    Three areas are reported: geothermal administration, geothermal planning, and other geothermal activities. Administration covers the status of the Imperial Valley Environmental Project transfer, update of the Geothermal Resource Center, and findings of the geothermal field inspections. Planning addresses Board of Supervisor actions, Planning Commission actions, notice of exemptions, and the master Environmental Impact Report for Salton Sea. The other activity includes the County Direct Heat Development study; the solicitation for district heating and cooling proposals; the new Geothermal Class II-1 disposal site; the DOE Region IX meeting in Tucson; and USGA designating a new KGRA, the East Brawley KGRA, the Westmoreland KGRA, and revising the southern border of the Salton Sea KGRA. (MHR)

  11. Internal structure of fault zones in geothermal reservoirs: Examples from palaeogeothermal fields and potential host rocks

    Science.gov (United States)

    Leonie Philipp, Sonja; Reyer, Dorothea; Meier, Silke; Bauer, Johanna F.; Afşar, Filiz

    2014-05-01

    Fault zones commonly have great effects on fluid transport in geothermal reservoirs. During fault slip all the pores and small fractures that meet with the slip plane become interconnected so that the inner part of the fault, the fault core, consisting of breccia or gouge, may suddenly develop a very high permeability. This is evidenced, for example by networks of mineral veins in deeply eroded fault zones in palaeogeothermal fields. Inactive faults, however, may have low permeabilities and even act as flow barriers. In natural and man-made geothermal reservoirs, the orientation of fault zones in relation to the current stress field and their internal structure needs be known as accurately as possible. One reason is that the activity of the fault zone depends on its angle to the principal stress directions. Another reason is that the outer part of a fault zone, the damage zone, comprises numerous fractures of various sizes. Here we present field examples of faults, and associated joints and mineral veins, in palaeogeothermal fields, and potential host rocks for man-made geothermal reservoirs, respectively. We studied several localities of different stratigraphies, lithologies and tectonic settings: (1) 58 fault zones in 22 outcrops from Upper Carboniferous to Upper Cretaceous in the Northwest German Basin (siliciclastic, carbonate and volcanic rocks); (2) 16 fault zones in 9 outcrops in Lower Permian to Middle Triassic (mainly sandstone, limestone and granite) in the Upper Rhine Graben; and (3) 74 fault zones in two coastal sections of Upper Triassic and Lower Jurassic age (mudstones and limestone-marl alternations) in the Bristol Channel Basin, UK. (1) and (2) are outcrop analogues of geothermal reservoir horizons, (3) represent palaeogeothermal fields with mineral veins. The field studies in the Northwest German Basin (1) show pronounced differences between normal-fault zones in carbonate and clastic rocks. In carbonate rocks clear damage zones occur that are

  12. Niland development project geothermal loan guaranty: 49-MW (net) power plant and geothermal well field development, Imperial County, California: Environmental assessment

    Energy Technology Data Exchange (ETDEWEB)

    1984-10-01

    The proposed federal action addressed by this environmental assessment is the authorization of disbursements under a loan guaranteed by the US Department of Energy for the Niland Geothermal Energy Program. The disbursements will partially finance the development of a geothermal well field in the Imperial Valley of California to supply a 25-MW(e) (net) power plant. Phase I of the project is the production of 25 MW(e) (net) of power; the full rate of 49 MW (net) would be achieved during Phase II. The project is located on approximately 1600 acres (648 ha) near the city of Niland in Imperial County, California. Well field development includes the initial drilling of 8 production wells for Phase I, 8 production wells for Phase II, and the possible need for as many as 16 replacement wells over the anticipated 30-year life of the facility. Activities associated with the power plant in addition to operation are excavation and construction of the facility and associated systems (such as cooling towers). Significant environmental impacts, as defined in Council on Environmental Quality regulation 40 CFR Part 1508.27, are not expected to occur as a result of this project. Minor impacts could include the following: local degradation of ambient air quality due to particulate and/or hydrogen sulfide emissions, temporarily increased ambient noise levels due to drilling and construction activities, and increased traffic. Impacts could be significant in the event of a major spill of geothermal fluid, which could contaminate groundwater and surface waters and alter or eliminate nearby habitat. Careful land use planning and engineering design, implementation of mitigation measures for pollution control, and design and implementation of an environmental monitoring program that can provide an early indication of potential problems should ensure that impacts, except for certain accidents, will be minimized.

  13. Hydrogeochemical and isotopic characteristics of Kavak (Seydişehir-Konya) geothermal field, Turkey

    Science.gov (United States)

    Bozdağ, Ayla

    2016-09-01

    The Kavak geothermal field is located 13 km north of Seydişehir town, about 90 km southwest of Konya Province in the Central Anatolia, Turkey. This study was carried out to determine the origin, chemical characteristics, and isotopic composition of Kavak thermal waters. The measured temperatures of thermal and mineral waters range from 21.5 to 26 °C with a discharge of 0.8 l/s in springs, and from 30 to 45.8 °C with a discharge of 185 l/s in wells. Thermal and/or mineralized spring and well waters are of Casbnd Nasbnd HCO3 types with electrical conductivity ranging from 2530 to 4150 μS/cm while cold groundwater is mainly of Casbnd HCO3 and Casbnd Mgsbnd HCO3 types with electrical conductivity ranging from 446 to 668 μS/cm. Kavak thermal waters have not reached complete chemical re-equilibrium possibly as a result of mixing with cold water during upward flow. Assessments from quartz geothermometers and fluid-mineral equilibria calculations suggest that reservoir temperature of Kavak geothermal field ranges from 68 to 105 °C. Thermal waters are oversaturated at discharge temperatures for calcite, dolomite, and aragonite minerals corresponding to travertine precipitation in the discharge area. Gypsum and anhydrite minerals are undersaturated in all the thermal waters. The δ18O and δ2H compositions of Kavak thermal and cold waters point to a meteoric origin. Meteoric waters infiltrate the reservoir rocks along faults and fracture zones. After being heated at depth with the high geothermal gradient, they move up to the surface along faults and fractures that act as pathways. Additionally, δ18O and δ2H values suggest that thermal waters are recharged from higher elevations in comparison with cold waters. Long-term circulation of meteoric waters within the basement rocks is indicated by low tritium (<2 TU) values in the thermal waters, although the fluids do not achieve thermodynamic equilibrium. Based on the δ13C values, carbon in thermal waters is considered

  14. INVESTIGATION OF DISSOLVED SULPHATE IN VARIOUS GEOTHERMAL FIELDS OF SUMATRA USING OXYGEN AND SULPHUR ISOTOPES

    Directory of Open Access Journals (Sweden)

    E. Ristin Pujiindiyati

    2010-06-01

    Full Text Available There are at least 30 high temperature systems; eleven active volcanoes, five degassing volcanoes and one caldera volcano controlled by Sumatra Fault Zone over a length of 1700 km. To understand this geothermal field system, some information about geochemistry including isotope composition in its fluid is needed. Sulphur-34 and oxygen-18 isotopes in dissolved sulphate pair have been used to determine the origin of acidic fluid of sulphate and to evaluate the process involved. The fluids from eight hot springs, two fumaroles, four deep wells and crater have been collected in along Sumatra geothermal fields. Sulphur-34 (d 34S (SO4, 0/00 CDT and oxygen-18 (d 18O (SO4, 0/00 SMOW in sulphate is analyzed according to Robinson-Kusakabe and Rafter method, respectively. The d 34S (SO4 values from Sibayak wells are more enriched of 16.8 0/00 to 18.2 0/0 that may indicate the dissolution of anhydrite minerals or isotope partitioning in hydration of SO2. The d 34S (SO4 values from two fumaroles (Pusuk Bukit - North Sumatra and Rantau Dadap - South Sumatra are at depleted value of -0.150/00 and 1.80/00, those are close to d 34S from magmatic sulphur.  In general, the d 34S (SO4 of springs spread in a wide range of 5.250/00 to14.20/00 and show a mixing process between atmospheric sulphate and sulphate from deep wells. The d 18O (SO4 from wells exhibits depleted value around -3.60/00 suggesting that 87.5% of sulphate oxygen is derived from groundwater oxygen and 12.5% is derived from atmospheric molecular oxygen in sulphide oxidation reaction. In the other hand, hot springs (except Semurup, crater and fumaroles have enriched value of d 18O (SO4. These enriched values suggest that a higher percentage of atmospherically derived oxygen compared to those from the depth.   Keywords: isotope, geothermal, Sumatra

  15. A comparison of long-term changes in seismicity at The Geysers, Salton Sea, and Coso geothermal fields

    Science.gov (United States)

    Trugman, Daniel T.; Shearer, Peter M.; Borsa, Adrian A.; Fialko, Yuri

    2016-01-01

    Geothermal energy is an important source of renewable energy, yet its production is known to induce seismicity. Here we analyze seismicity at the three largest geothermal fields in California: The Geysers, Salton Sea, and Coso. We focus on resolving the temporal evolution of seismicity rates, which provides important observational constraints on how geothermal fields respond to natural and anthropogenic loading. We develop an iterative, regularized inversion procedure to partition the observed seismicity rate into two components: (1) the interaction rate due to earthquake-earthquake triggering and (2) the smoothly varying background rate controlled by other time-dependent stresses, including anthropogenic forcing. We apply our methodology to compare long-term changes in seismicity to monthly records of fluid injection and withdrawal. At The Geysers, we find that the background seismicity rate is highly correlated with fluid injection, with the mean rate increasing by approximately 50% and exhibiting strong seasonal fluctuations following construction of the Santa Rosa pipeline in 2003. In contrast, at both Salton Sea and Coso, the background seismicity rate has remained relatively stable since 1990, though both experience short-term rate fluctuations that are not obviously modulated by geothermal plant operation. We also observe significant temporal variations in Gutenberg-Richter b value, earthquake magnitude distribution, and earthquake depth distribution, providing further evidence for the dynamic evolution of stresses within these fields. The differing field-wide responses to fluid injection and withdrawal may reflect differences in in situ reservoir conditions and local tectonics, suggesting that a complex interplay of natural and anthropogenic stressing controls seismicity within California's geothermal fields.

  16. Chemical Stimulation Treatment of the Rossi 21-19 Well Beowawe Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    None

    1984-01-01

    The tests reported were part of the DOE Geothermal Reservoir Well Stimulation Program. This was an attempt to ameliorate near-wellbore restricted permeability in a well at a field where other wells flowed at high rates. The two stage treatment first injected HCl followed by a large volume of HCl-HF acid solution. This was a relatively inexpensive treatment, with costs shown. Injectivity tests showed a 2.2 fold increase in injectivity attributable to the second treatment, but mechanical complications with the well precluded an adequate production test. Flow of the fluid out into the formation was measured by Sandia using surface electrical potential. LANL detected microseismic events during the stimulation, which might be especially significant.

  17. Chemical Stimulation Treatment of the Rossi 21-19 Well Beowawe Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    None

    1984-01-01

    The tests reported were part of the DOE Geothermal Reservoir Well Stimulation Program. This was an attempt to ameliorate near-wellbore restricted permeability in a well at a field where other wells flowed at high rates. The two stage treatment first injected HCl followed by a large volume of HCl-HF acid solution. This was a relatively inexpensive treatment, with costs shown. Injectivity tests showed a 2.2 fold increase in injectivity attributable to the second treatment, but mechanical complications with the well precluded an adequate production test. Flow of the fluid out into the formation was measured by Sandia using surface electrical potential. LANL detected microseismic events during the stimulation, which might be especially significant.

  18. Development And Application Of A Hydrothermal Model For The Salton Sea Geothermal Field, California

    Energy Technology Data Exchange (ETDEWEB)

    Kasameyer, P.; Younker, L.; Hanson, J.

    1984-01-01

    A simple lateral flow model adequately explains many of the features associated with the Salton Sea Geothermal Field. Earthquake swarms, a magnetic anomaly, and aspects of the gravity anomaly are all indirect evidence for the igneous activity which is the ultimate source of heat for the system. Heat is transferred from this area of intrusion by lateral spreading of hot water in a reservoir beneath an impermeable cap rock. A two dimensional analytic model encompassing this transport mechanism matches general features of the thermal anomaly and has been used to estimate the age of the presently observed thermal system. The age is calculated by minimizing the variance between the observed surface heat-flow data and the model. Estimates of the system age for this model range from 3,000 to 20,000 years.

  19. Temporal static stress drop variations due to injection activity at The Geysers geothermal field, California

    Science.gov (United States)

    Staszek, M.; Orlecka-Sikora, B.; Leptokaropoulos, K.; Kwiatek, G.; Martínez-Garzón, P.

    2017-07-01

    We use a high-quality data set from the NW part of The Geysers geothermal field to determine statistical significance of temporal static stress drop variations and their relation to injection rate changes. We use a group of 322 seismic events which occurred in the proximity of Prati-9 and Prati-29 injection wells to examine the influence of parameters such as moment magnitude, focal mechanism, hypocentral depth, and normalized hypocentral distances from open-hole sections of injection wells on static stress drop changes. Our results indicate that (1) static stress drop variations in time are statistically significant, (2) statistically significant static stress drop changes are inversely related to injection rate fluctuations. Therefore, it is highly expected that static stress drop of seismic events is influenced by pore pressure in underground fluid injection conditions and depends on the effective normal stress and strength of the medium.

  20. Geothermal Field Development in the European Community Objectives, Achievements and Problem Areas

    Energy Technology Data Exchange (ETDEWEB)

    Ungemach, Pierre

    1983-12-15

    Achievements and problem areas are reviewed with respect to various engineering implications of geothermal field development in the European Community (EC). Current and furture development goals address three resource settings. (a) low enthalpy sources (30-150{degrees}C), an outlook common to all Member states as a result of hot water aquifers flowing in large sedimentary units with normal heat flow, widespread thoughout the EC; (b) high enthalpy sources (<150{degrees}C) in areas of high heat flow which, as a consequence of the geodynamics of the Eurasian plate, are limited to Central and South-West Italy and to Eastern Greece; (c) hot dry rocks (HDR), whose potential for Europe, and also the difficulties in implementing the heat mining concept, are enormous. A large scale experiment conducted at medium depth in Cornwall (UK) proves encouraging though. It has provided the right sort of scientific inputs to the understanding of the mechanics of anisotropic brittle basement rocks.

  1. Geological Results from Drilling in the Poihipi (Western) Sector of the Wairakei Geothermal Field, NZ

    Energy Technology Data Exchange (ETDEWEB)

    Bogie, I.; Lawless, J.V.; MacKenzie, K.M.

    1995-01-01

    Four wells drilled into the Poihipi Sector on the Western margin of the Wairakei geothermal field have found a similar lithostratigraphy to that encountered in wells previously drilled in the general area. Young pumice breccias overly the Huka Falls Formation, with the latter containing intercalations of the Rautehuia Breccia. This in turn overlies ignimbrites and tuffaceous sediments of the Waiora Formation, which contains flows of Haparangi Rhyolite. This sequence is cut by steeply dipping normal faults which strike to the northeast and for the most part dip towards the northwest. Hydrothermal alteration is virtually limited to the Waiora and Haparangi units where a sequence of interlayered illite-smectite and illite clays are found along with chlorite, quartz, pyrite and calcite. There is a minor occurrence of zeolites. Despite large changes in the area's hydrology in response to exploitation, changes in alteration are limited to a comparatively deep occurrence of kaolinite and minor overprinting of epidote by illitic clay.

  2. Analysis of field-performance data on shell-and-tube heat exchangers in geothermal service

    Energy Technology Data Exchange (ETDEWEB)

    Silvester, L.F.; Doyle, P.T.

    1982-03-01

    Analysis of field performance data from a binary cycle test loop using geothermal brine and a hydrocarbon working fluid is reported. Results include test loop operational problems, and shell-and-tube heat exchanger performance factors such as overall heat transfer coefficients, film coefficients, pinch points, and pressure drops. Performance factors are for six primary heaters having brine in the tubes and hydrocarbon in the shells in counterflow, and for a condenser having cooling water in the tubes and hydrocarbon in the shell. Working fluids reported are isobutane, 90/10 isobutane/isopentane, and 80/20 isobutane/isopentane. Performance factors are for heating each working fluid at supercritical conditions in the vicinity of their critical pressure and temperature and condensing the same fluid.

  3. Geochemical Enhancement Of Enhanced Geothermal System Reservoirs: An Integrated Field And Geochemical Approach

    Energy Technology Data Exchange (ETDEWEB)

    Joseph N. Moore

    2007-12-31

    The geochemical effects of injecting fluids into geothermal reservoirs are poorly understood and may be significantly underestimated. Decreased performance of injection wells has been observed in several geothermal fields after only a few years of service, but the reasons for these declines has not been established. This study had three primary objectives: 1) determine the cause(s) of the loss of injectivity; 2) utilize these observations to constrain numerical models of water-rock interactions; and 3) develop injection strategies for mitigating and reversing the potential effects of these interactions. In this study rock samples from original and redrilled injection wells at Coso and the Salton Sea geothermal fields, CA, were used to characterize the mineral and geochemical changes that occurred as a result of injection. The study documented the presence of mineral scales and at both fields in the reservoir rocks adjacent to the injection wells. At the Salton Sea, the scales consist of alternating layers of fluorite and barite, accompanied by minor anhydrite, amorphous silica and copper arsenic sulfides. Amorphous silica and traces of calcite were deposited at Coso. The formation of silica scale at Coso provides an example of the effects of untreated (unacidified) injectate on the reservoir rocks. Scanning electron microscopy and X-ray diffractometry were used to characterize the scale deposits. The silica scale in the reservoir rocks at Coso was initially deposited as spheres of opal-A 1-2 micrometers in diameter. As the deposits matured, the spheres coalesced to form larger spheres up to 10 micrometer in diameter. Further maturation and infilling of the spaces between spheres resulted in the formation of plates and sheets that substantially reduce the original porosity and permeability of the fractures. Peripheral to the silica deposits, fluid inclusions with high water/gas ratios provide a subtle record of interactions between the injectate and reservoir rocks

  4. The structural architecture of the Los Humeros volcanic complex and geothermal field, Trans-Mexican Volcanic Belt, Central Mexico

    Science.gov (United States)

    Norini, Gianluca; Groppelli, Gianluca; Sulpizio, Roberto; Carrasco Núñez, Gerardo; Davila Harris, Pablo

    2014-05-01

    The development of geothermal energy in Mexico is a very important goal, given the presence of a large heat anomaly, associated with the Trans-Mexican Volcanic Belt, the renewability of the resource and the low environmental impact. The Quaternary Los Humeros volcanic complex is an important geothermal target, whose evolution involved at least two caldera events, that alternated with other explosive and effusive activity. The first caldera forming event was the 460 ka eruption that produced the Xaltipan ignimbrite and formed a 15-20 km wide caldera. The second collapse event occurred 100 ka with the formation of the Zaragoza ignimbrite and a nested 8-10 km wide caldera. The whole volcano structure, the style of the collapses and the exact location of the calderas scarps and ring faults are still a matter of debate. The Los Humeros volcano hosts the productive Los Humeros Geothermal Field, with an installed capacity of 40 MW and additional 75 MW power plants under construction. Recent models of the geothermal reservoir predict the existence of at least two reservoirs in the geothermal system, separated by impermeable rock units. Hydraulic connectivity and hydrothermal fluids circulation occurs through faults and fractures, allowing deep steam to ascend while condensate flows descend. As a consequence, the plans for the exploration and exploitation of the geothermal reservoir have been based on the identification of the main channels for the circulation of hydrothermal fluids, constituted by faults, so that the full comprehension of the structural architecture of the caldera is crucial to improve the efficiency and minimize the costs of the geothermal field operation. In this study, we present an analysis of the Los Humeros volcanic complex focused on the Quaternary tectonic and volcanotectonics features, like fault scarps and aligned/elongated monogenetic volcanic centres. Morphostructural analysis and field mapping reveal the geometry, kinematics and dynamics of

  5. Influence of shallow flow on the deep geothermal field of Berlin - Results from 3D models

    Science.gov (United States)

    Frick, Maximilian; Sippel, Judith; Scheck-Wenderoth, Magdalena; Cacace, Mauro; Hassanzadegan, Alireza

    2015-04-01

    The goal of this study is to quantify the influence of fluid-driven heat transport on the subsurface temperature distribution of the city of Berlin, Germany. Berlin is located in the Northeast German Basin filled with several kilometers of sediments. Two of the clastic sedimentary units, namely the Middle Buntsandstein and the Sedimentary Rotliegend are of particular interest for geothermal exploration. Previous studies in the Northeast German Basin have already shown that subsurface temperature distributions are highly dependent on the geometries and properties of the geological units. Our work benefits strongly from these studies that involve numerical modeling of coupled conductive and convective heat transport. We follow a two-step approach where we first improve an existing structural model by integrating newly available 57 geological cross-sections, well data and deep seismics (down to ~4 km). Secondly, we perform a sensitivity analysis in which we investigate the effects of varying physical fluid and rock properties as well as hydraulic and thermal boundary conditions on the resulting temperature configuration. Computed temperatures are validated via comparison with existing well temperature measurements in the area. Of special interest for this study is the influence of the shallow aquifer systems on the subsurface temperature field. The major constituents of this system are the Quaternary silts and sands, the Tertiary Rupelian clay and the Tertiary sands beneath the Rupelian. These units have different hydraulic properties. The Rupelian clay represents a major aquitard in this respect hydraulically disconnecting the pre- and post-Rupelian succession. This aquitard shows a heterogeneous thickness distribution locally characterized by different hydrogeological windows (i.e. domains of no thickness) enabling intra-aquifer groundwater circulation at depth thus having a first-order effect on the shallow thermal field. As result of the simulations, we present

  6. Geothermal Energy

    Science.gov (United States)

    1975-11-15

    kaolinization . Deposition of silica can easily be observed in the Geysers field, where fractures of one-inch width, completely filled and sealed...by silica and calcite, are common features. Kaolinization , associated with other more complicated hydrothermal rock alteration, is also...techniques. Surface corrosion may be extremely severe in geothermal fluids containing free hydrochloric, sulphuric or hydrofluoric acid

  7. Assessing Past Fracture Connectivity in Geothermal Reservoirs Using Clumped Isotopes: Proof of Concept in the Blue Mountain Geothermal Field, Nevada USA

    Science.gov (United States)

    Huntington, K. W.; Sumner, K. K.; Camp, E. R.; Cladouhos, T. T.; Uddenberg, M.; Swyer, M.; Garrison, G. H.

    2015-12-01

    Subsurface fluid flow is strongly influenced by faults and fractures, yet the transmissivity of faults and fractures changes through time due to deformation and cement precipitation, making flow paths difficult to predict. Here we assess past fracture connectivity in an active hydrothermal system in the Basin and Range, Nevada, USA, using clumped isotope geochemistry and cold cathodoluminescence (CL) analysis of fracture filling cements from the Blue Mountain geothermal field. Calcite cements were sampled from drill cuttings and two cores at varying distances from faults. CL microscopy of some of the cements shows banding parallel to the fracture walls as well as brecciation, indicating that the cements record variations in the composition and source of fluids that moved through the fractures as they opened episodically. CL microscopy, δ13C and δ18O values were used to screen homogeneous samples for clumped isotope analysis. Clumped isotope thermometry of most samples indicates paleofluid temperatures of around 150°C, with several wells peaking at above 200°C. We suggest that the consistency of these temperatures is related to upwelling of fluids in the convective hydrothermal system, and interpret the similarity of the clumped isotope temperatures to modern geothermal fluid temperatures of ~160-180°C as evidence that average reservoir temperatures have changed little since precipitation of the calcite cements. In contrast, two samples, one of which was associated with fault gauge observed in drill logs, record significantly cooler temperatures of 19 and 73°C and anomalous δ13C and δ18Owater values, which point to fault-controlled pathways for downwelling meteoric fluid. Finally, we interpret correspondence of paleofluid temperatures and δ18Owater values constrained by clumped isotope thermometry of calcite from different wells to suggest past connectivity of fractures among wells within the geothermal field. Results show the ability of clumped isotope

  8. Fluid circulation and reservoir conditions of the Los Humeros Geothermal Field (LHGF), Mexico, as revealed by a noble gas survey

    Science.gov (United States)

    Pinti, Daniele L.; Castro, M. Clara; Lopez-Hernandez, Aida; Han, Guolei; Shouakar-Stash, Orfan; Hall, Chris M.; Ramírez-Montes, Miguel

    2017-03-01

    Los Humeros Geothermal Field (LHGF) is one of four geothermal fields currently operating in Mexico, in exploitation since 1990. Located in a caldera complex filled with very low-permeability rhyolitic ignimbrites that are the reservoir cap-rock, recharge of the geothermal field is both limited and localized. Because of this, planning of any future geothermal exploitation must be based on a clear understanding of the fluid circulation. To this end, a first noble gas survey was carried out in which twenty-two production wells were sampled for He, Ne, Ar, Kr, and Xe isotope analysis. Air-corrected 3He/4He ratios (Rc) measured in the fluid, normalized to the helium atmospheric ratio (Ra; 1.384 × 10- 6), are consistently high across the field, with an average value of 7.03 ± 0.40 Ra. This value is close to that of the sub-continental upper mantle, indicating that LHGF mines heat from an active magmatic system. Freshwater recharge does not significantly affect He isotopic ratios, contributing 1-10% of the total fluid amount. The presence of radiogenic 40Ar* in the fluid suggests a fossil fluid component that might have circulated within the metacarbonate basement with radiogenic argon produced from detrital dispersed illite. Solubility-driven elemental fractionation of Ne/Ar, Kr/Ar, and Xe/Ar confirm extreme boiling in the reservoir. However, a combined analysis of these ratios with 40Ar/36Ar reveals mixing with an air component, possibly introduced by re-injected geothermal fluids.

  9. Hydrothermal alteration and fluid inclusion geothermometry of Los Humeros geothermal field, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Prol-Ledesma, R.M. (Inst. de Geofisica and DEPFI, UNAM, Cd. Univ., Coyoacan 04510 (MX)); Browne, P.R.L. (Geothermal Inst. and Geology Dept., Auckland Univ., Private Bag, Auckland (NZ))

    1989-01-01

    The Los Humeros geothermal field, located in Puebla State, Mexico, occurs in a caldera; drillholes to 3000 m depth encountered a sequence of Quaternary lavas and pyroclastic rocks that range in composition from rhyolite to basalt but are dominantly andesitic. These rest upon the local basement comprising limestone and siltstone of Cretaceous age, which was encountered below 2500 m in the northern part of the field and 1000 m in its southern part. Examination of 29 cores, mostly from below 900 m depth, from 14 wells show that the hydrothermal minerals that occur in the volcanic host rocks include quarts, calcite, epidote, amphibole, sericite, smectite, illite, chlorite, biotite, pyrite and hematite. Their distribution mainly reflects the prevailing hydrological and thermal regime where temperatures locally exceed 300{degrees} C. A preliminary model for the hydrology of the field based upon the hydrothermal alteration mineralogy and fluid inclusion data suggests that dilute hot water ascends via faults in the Central Caldera collapse area of the field and moves laterally outward to elsewhere within the caldera.

  10. Integrated Resistivity and Ground Penetrating Radar Observations of Underground Seepage of Hot Water at Blawan-Ijen Geothermal Field

    Directory of Open Access Journals (Sweden)

    Sukir Maryanto

    2016-01-01

    Full Text Available Geothermal resource investigation was accomplished for Blawan-Ijen geothermal system. Blawan geothermal field which located in the northern part of Ijen caldera presents hydrothermal activity related with Pedati fault and local graben. There were about 21 hot springs manifestations in Blawan-Ijen area with calculated temperature about 50°C. We have performed several geophysical studies of underground seepage of hot water characterization. The geoelectric resistivity and GPR methods are used in this research because both of them are very sensitive to detect the presence of hot water. These preliminary studies have established reliable methods for hydrothermal survey that can accurately investigate the underground seepage of hot water with shallow depth resolution. We have successfully identified that the underground seepage of hot water in Blawan geothermal field is following the fault direction and river flow which is evidenced by some hot spring along the Banyu Pahit river with resistivity value less than 40 Ωm and medium conductivity.

  11. Using earthquake clusters to identify fracture zones at Puna geothermal field, Hawaii

    Science.gov (United States)

    Lucas, A.; Shalev, E.; Malin, P.; Kenedi, C. L.

    2010-12-01

    The actively producing Puna geothermal system (PGS) is located on the Kilauea East Rift Zone (ERZ), which extends out from the active Kilauea volcano on Hawaii. In the Puna area the rift trend is identified as NE-SW from surface expressions of normal faulting with a corresponding strike; at PGS the surface expression offsets in a left step, but no rift perpendicular faulting is observed. An eight station borehole seismic network has been installed in the area of the geothermal system. Since June 2006, a total of 6162 earthquakes have been located close to or inside the geothermal system. The spread of earthquake locations follows the rift trend, but down rift to the NE of PGS almost no earthquakes are observed. Most earthquakes located within the PGS range between 2-3 km depth. Up rift to the SW of PGS the number of events decreases and the depth range increases to 3-4 km. All initial locations used Hypoinverse71 and showed no trends other than the dominant rift parallel. Double difference relocation of all earthquakes, using both catalog and cross-correlation, identified one large cluster but could not conclusively identify trends within the cluster. A large number of earthquake waveforms showed identifiable shear wave splitting. For five stations out of the six where shear wave splitting was observed, the dominant polarization direction was rift parallel. Two of the five stations also showed a smaller rift perpendicular signal. The sixth station (located close to the area of the rift offset) displayed a N-S polarization, approximately halfway between rift parallel and perpendicular. The shear wave splitting time delays indicate that fracture density is higher at the PGS compared to the surrounding ERZ. Correlation co-efficient clustering with independent P and S wave windows was used to identify clusters based on similar earthquake waveforms. In total, 40 localized clusters containing ten or more events were identified. The largest cluster was located in the

  12. Geological, Geophysical, And Thermal Characteristics Of The Salton Sea Geothermal Field, California

    Energy Technology Data Exchange (ETDEWEB)

    Younker, L.W.; Kasameyer, P. W.; Tewhey, J. D.

    1981-01-01

    The Salton Sea Geothermal Field is the largest water-dominated geothermal field in the Salton Trough in Southern California. Within the trough, local zones of extension among active right-stepping right-lateral strike-slip faults allow mantle-derived magmas to intrude the sedimentary sequence. The intrusions serves as heat sources to drive hydrothermal systems. We can characterize the field in detail because we have an extensive geological and geophysical data base. The sediments are relatively undeformed and can be divided into three categories as a function of depth: (1) low-permeability cap rock, (2) upper reservoir rocks consisting of sandstones, siltstones, and shales that were subject to minor alterations, and (3) lower reservoir rocks that were extensively altered. Because of the alteration, intergranular porosity and permeability are reduced with depth. permeability is enhanced by renewable fractures, i.e., fractures that can be reactivated by faulting or natural hydraulic fracturing subsequent to being sealed by mineral deposition. In the central portion of the field, temperature gradients are high near the surface and lower below 700 m. Surface gradients in this elliptically shaped region are fairly constant and define a thermal cap, which does not necessarily correspond to the lithologic cap. At the margin of the field, a narrow transition region, with a low near-surface gradient and an increasing gradient at greater depths, separates the high temperature resource from areas of normal regional gradient. Geophysical and geochemical evidence suggest that vertical convective motion in the reservoir beneath the thermal cap is confined to small units, and small-scale convection is superimposed on large-scale lateral flow of pore fluid. Interpretation of magnetic, resistivity, and gravity anomalies help to establish the relationship between the inferred heat source, the hydrothermal system, and the observed alteration patterns. A simple hydrothermal model is

  13. Predicting thermal conductivity of rocks from the Los Azufres geothermal field, Mexico, from easily measurable properties

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Alfonso; Contreras, Enrique; Dominquez, Bernardo A.

    1988-01-01

    A correlation is developed to predict thermal conductivity of drill cores from the Los Azufres geothermal field. Only andesites are included as they are predominant. Thermal conductivity of geothermal rocks is in general scarce and its determination is not simple. Almost all published correlations were developed for sedimentary rocks. Typically, for igneous rocks, chemical or mineral analyses are used for estimating conductivity by using some type of additive rule. This requires specialized analytical techniques and the procedure may not be sufficiently accurate if, for instance, a chemical analysis is to be changed into a mineral analysis. Thus a simple and accurate estimation method would be useful for engineering purposes. The present correlation predicts thermal conductivity from a knowledge of bulk density and total porosity, properties which provide basic rock characterization and are easy to measure. They may be determined from drill cores or cuttings, and the procedures represent a real advantage given the cost and low availability of cores. The multivariate correlation proposed is a quadratic polynomial and represents a useful tool to estimate thermal conductivity of igneous rocks since data on this property is very limited. For porosities between 0% and 25%, thermal conductivity is estimated with a maximum deviation of 22% and a residual mean square deviation of 4.62E-3 n terms of the log{sub 10}(k{rho}{sub b}) variable. The data were determined as part of a project which includes physical, thermal and mechanical properties of drill cores from Los Azufres. For the correlation, sixteen determinations of thermal conductivity, bulk density and total porosity are included. The conductivity data represent the first determinations ever made on these rocks.

  14. Thermal and petrologic constraints on lower crustal melt accumulation under the Salton Sea Geothermal Field

    Science.gov (United States)

    Karakas, Ozge; Dufek, Josef; Mangan, Margaret T.; Wright, Heather M.; Bachmann, Olivier

    2017-06-01

    In the Salton Sea region of southern California (USA), concurrent magmatism, extension, subsidence, and sedimentation over the past 0.5 to 1.0 Ma have led to the creation of the Salton Sea Geothermal Field (SSGF)-the second largest and hottest geothermal system in the continental United States-and the small-volume rhyolite eruptions that created the Salton Buttes. In this study, we determine the flux of mantle-derived basaltic magma that would be required to produce the elevated average heat flow and sustain the magmatic roots of rhyolite volcanism observed at the surface of the Salton Sea region. We use a 2D thermal model to show that a lower-crustal, partially molten mush containing < 20- 40% interstitial melt develops over a ∼105-yr timescale for basalt fluxes of 0.008 to 0.010 m3 /m2 /yr (∼0.0008 to ∼0.001 km3/yr injection rate) given extension rates at or below the current value of ∼0.01 m/yr (Brothers et al., 2009). These regions of partial melt are a natural consequence of a thermal regime that scales with average surface heat flow in the Salton Trough, and are consistent with seismic observations. Our results indicate limited melting and assimilation of pre-existing rocks in the lower crust. Instead, we find that basalt fractionation in the lower crust produces derivative melts of andesitic to dacitic composition. Such melts are then expected to ascend and accumulate in the upper crust, where they further evolve to give rise to small-volume rhyolite eruptions (Salton Buttes) and fuel local spikes in surface heat flux as currently seen in the SSGF. Such upper crustal magma evolution, with limited assimilation of hydrothermally altered material, is required to explain the slight decrease in δ18 O values of zircons (and melts) that have been measured in these rhyolites.

  15. 断裂构造对地热田形成的控制作用%Control of Faults on the Geothermal Field Formed

    Institute of Scientific and Technical Information of China (English)

    赵亚娟; 刘立军; 张少才; 牛树银; 夏帅; 王敏; 王雨豪

    2016-01-01

    Niutuo geothermal field is located in Central Beijing, Tianjin and Bao hinterland of economic development,as has rich geothermal reserves,including wide distribution area and low-temperature geothermal resources.Our studies suggest that broken projections in Niutuo is relatively complete.Faults are well developed in geothermal field through the analysis of geothermal fields to spread morphology and thermal energy storage feature, including the geothermal field distribution.Then we discuss the analysis under the mantle plume control the heat source formation,upward migration and the formation of geothermal fields.%河北牛驼镇地热田位于环京、津、保经济发展的腹地,拥有地热储量丰富、分布面积广的中—低温地热资源。研究认为:牛驼镇断凸是一个相对完整的、断裂构造比较发育的地热田。通过分析地热田展布形态、热储特征、地温场分布特征,进而探讨了地幔热柱控制下其热源的形成、向上运移,及其地热田的形成。

  16. Integrated geophysical imaging of the Aluto-Langano geothermal field (Ethiopia).

    Science.gov (United States)

    Rizzello, Daniele; Armadillo, Egidio; Verdoya, Massimo; Pasqua, Claudio; Kebede, Solomon; Mengiste, Andarge; Hailegiorgis, Getenesh; Abera, Fitsum; Mengesha, Kebede; Meqbel, Naser

    2017-04-01

    The Aluto-Langano geothermal system is located in the central part of the Main Ethiopian Rift, one of the world's most tectonically active areas, where continental rifting has been occurring since several Ma and has yielded widespread volcanism and enhanced geothermal gradient. The geothermal system is associated to the Mt Aluto Volcanic Complex, located along the eastern margin of the rift and related to the Wonji Fault Belt, constituted by Quaternary NNE-SSW en-echelon faults. These structures are younger than the NE-SW border faults of the central Main Ethiopian Rift and were originated by a stress field oblique to the rift direction. This peculiar tectonism yielded local intense rock fracturing that may favour the development of geothermal reservoirs. In this paper, we present the results of an integrated geophysical survey carried out in 2015 over an area of about 200 km2 covering the Mt Aluto Volcanic Complex. The geophysical campaign included 162 coincident magnetotelluric and time domain electromagnetic soundings, and 207 gravity stations, partially located in the sedimentary plain surrounding the volcanic complex. Three-dimensional inversion of the full MT static-corrected tensor and geomagnetic tipper was performed in the 338-0.001 Hz band. Gravity data processing comprised digital enhancement of the residual Bouguer anomaly and 2D-3D inverse modelling. The geophysical results were compared to direct observations of stratigraphy, rock alteration and temperature available from the several deep wells drilled in the area. The magnetotelluric results imaged a low-resistivity layer which appears well correlated with the mixed alteration layer found in the wells and can be interpreted as a low-temperature clay cap. The clay-cap bottom depth is well corresponds to a change of thermal gradient. The clay cap is discontinuous, and in the central area of the volcanic complex is characterised by a dome-shape structure likely related to isotherm rising. The propilitic

  17. A closely-spaced magnetotelluric study of the Ahuachapan-Chipilapa geothermal field, El Salvador

    Energy Technology Data Exchange (ETDEWEB)

    Romo, Jose Manuel; Flores, Carlos; Vega, Raymundo; Vazquez, Rogelio; Flores, Marco A. Perez; Trevino, Enrique Gomez; Esparza, Francisco J.; Garcia, Victor H. [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Baja California (Mexico); Quijano, Julio E. [Comision Ejecutiva Hidroelectrica del Rio Lempa (CEL), Santa Tecla (El Salvador)

    1997-12-01

    The distribution of electrical conductivity beneath the Ahuachapan-Chipilapa geothermal area was simulated using 2-D models based on 126 closely-spaced magnetotelluric (MT) measurements. The observed MT response was interpreted as being produced by the superposition of two orthogonal geological structural systems: an approximately E-W regional trend associated with the Central Graben structure, which affects the loner period response, and a local and younger N-S fault system that is responsible for the short-to-intermediate period data. The MT response in the 0.02-10 s range period was used to simulate the conductivity structure within the first 2 km depth. By correlating the low-resistivity zones between twelve 2-D models, maps of the spatial distribution of conductors at three different depth levels were constructed. Three deep conductors were identified, one of the associated with the Ahuachapan reservoir, another apparently related to the Laguna Verde volcano, and a third one controlled by El Tortuguero Graben. The subsurface geometry of these conductivity anomalies suggests that the the Chipilapa and La Labor hot springs are supplied by two separate sources of hot fluids, one coming from the east and the other from the south or southwest. The distribution of the shallow high-conductivity zones agrees with the hydrothermal alteration zones mapped at the surface, suggesting that at shallow levels the argillitization process contributes significantly to the low resistivity. The large number of drillholes and the dense MT site coverage allowed the definition of important correlations between high temperatures and high conductivity, as well as between deep conductivity anomalies and productive wells. On this basis two years for future drilling are proposed. (Author)

  18. Archaeology in the Kilauea East Rift Zone: Part 1, Land-use model and research design, Kapoho, Kamaili and Kilauea Geothermal Subzones, Puna District, Hawaii Island

    Energy Technology Data Exchange (ETDEWEB)

    Burtchard, G.C.; Moblo, P. [International Archaeological Research Inst., Inc., Honolulu, HI (United States)

    1994-07-01

    The Puna Geothermal Resource Subzones (GRS) project area encompasses approximately 22,000 acres centered on the Kilauea East Rift Zone in Puna District, Hawaii Island. The area is divided into three subzones proposed for geothermal power development -- Kilauea Middle East Rift, Kamaili and Kapoho GRS. Throughout the time of human occupation, eruptive episodes along the rift have maintained a dynamic landscape. Periodic volcanic events, for example, have changed the coastline configuration, altered patterns of agriculturally suitable sediments, and created an assortment of periodically active, periodically quiescent, volcanic hazards. Because of the active character of the rift zone, then, the area`s occupants have always been obliged to organize their use of the landscape to accommodate a dynamic mosaic of lava flow types and ages. While the specific configuration of settlements and agricultural areas necessarily changed in response to volcanic events, it is possible to anticipate general patterns in the manner in which populations used the landscape through time. This research design offers a model that predicts the spatial results of long-term land-use patterns and relates them to the character of the archaeological record of that use. In essence, the environmental/land-use model developed here predicts that highest population levels, and hence the greatest abundance and complexity of identifiable prehistoric remains, tended to cluster near the coast at places that maximized access to productive fisheries and agricultural soils. With the possible exception of a few inland settlements, the density of archaeological remains expected to decrease with distance from the coastline. The pattern is generally supported in the regions existing ethnohistoric and archaeological record.

  19. Geothermal Frontier: Penetrate a boundary between hydrothermal convection and heat conduction zones to create 'Beyond Brittle Geothermal Reservoir'

    Science.gov (United States)

    Tsuchiya, N.; Asanuma, H.; Sakaguchi, K.; Okamoto, A.; Hirano, N.; Watanabe, N.; Kizaki, A.

    2013-12-01

    experiments, our research goals are 1)Analysis and understanding of geothermal structure and geofluids in ductile condition of the Japanese Island arc, 2)Fundamental technologies of drilling under ductile region for geothermal reservoir, 3) Development of geothermal reservoir simulator of two phase and multiphase flow including supercritical state through rock fracture, 4) Lab scale support for ICDP-JBBP, 5) Application of new EGS technologies to conventional geothermal fields as recovery from the 2011 Great East Japan Earthquake and energy crisis in Japan. [Publications Relevant to the Research] Tsuchiya, N. and Hirano, N. (2007), ISLAND ARC, 16, 6-15. Okamoto, A., Saishu, H., Hirano, N. & Tsuchiya, N. (2010) Geochimica et Cosmochimica Acta, 74, 3692-3706. Majer, E.L., Baria, R., Stark, M., Oates, S., Bonner, J. Smith, B. & Asanuma H., (2007) Geothermics, 36, 185-222. Watanabe, N., Hirano, N. Tsuchiya, N. (2009) Journal of Geophysical Research B: Solid Earth, 114(4), B04208.

  20. Performance Characteristics of Agricultural Field Machineries In South- East Nigeria

    Directory of Open Access Journals (Sweden)

    Oduma O

    2017-06-01

    Full Text Available The field performances of agricultural field machineries in South -East agricultural zone of Nigeria were assessed, to enable farmers and agriculturists select suitable farm machines/implements based on soil conditions/characteristics for their agricultural activities. The various implements studied include; disc plough, 2-gang tandem disc harrow, ridger, rotovator and 6-row combine seed planter. Three different makes and models of tractors namely: New Holland (model-NH5610SE and capacity-55.9kw, Massey Ferguson (model-MF430E and capacity-55.2kw and Mahindra (model-NH7570E and capacity-55.9kw with 3- point hitch systems and average age of 1.3 years were used to study the field performances of each of the implements, in five different states that made up the study area. The field performances studied include; implements working speed, operation time, depth of cut, effective and theoretical field capacities, field efficiency, fuel consumption rate, implement power requirements, and wheel slippage, under different soil conditions. Results obtained revealed that the disc plough had field efficiency range of 85.74% to 88.55%, effective and theoretical field capacities range of 0.846 to 1.164ha/hr and 0.961 to 1.319ha/hr respectively; and the highest field (ploughing efficiency was obtained in loamy-sandy soil when the plough was operated with the Massey Ferguson tractor. Harrow recorded field efficiency range of 80.17 to 91.38%, effective and theoretical field capacities range of 0.931 to 1.458ha/hr and 1.151 to 1.667 ha/hr respectively; and the highest field (harrowing efficiency was obtained on sandy-clay soil by New Holland tractor. Ridger recorded 83.65 to 88.82% field efficiency, 0.932 to 1.322ha/hr effective capacity and 1.073 to 1.504ha/hr theoretical field capacity; and sandy-clay gave the highest field (ridging efficiency when operated with a New Holland tractor. The rotovator had field efficiency range of 81.10 to 89.81%, effective and

  1. Remote triggering and numerical simulations of passing seismic waves at the Larderello-Travale Geothermal Field, Italy

    Science.gov (United States)

    Fuchs, Florian; Lupi, Matteo; Saenger, Erik

    2017-04-01

    Seismic waves generated by large magnitude earthquakes can affect geological systems located thousands of kilometers far from the epicenter. The Larderello-Travale geothermal field is one of the most studied high-enthalpy geothermal systems worldwide shown to be sensitive to incoming seismic energy. In this study we detected local seismic activity at the Larderello-Travale field, coinciding with the passage of Rayleigh waves released by the 2011 M9.0 Tohoku earthquake. The earthquakes of local magnitudes 1.6 and 1.7 occurred at 6 km and 8 km depth, respectively. We suggest that these earthquakes were dynamically triggered by transient Rayleigh waves which induced a maximum vertical displacement of approximately 7.5 mm at the hydrothermal field (for waves with period of 200 s). We estimate a dynamic stress of about 8 kPa for a measured peak ground velocity of 0.8 mm/s and propose that this additional stress in a clock-advance process triggered the local earthquakes which may have eventually occurred naturally at a later time. Previous studies also report increased seismic activity at the Larderello-Travale geothermal field after regional earthquakes. We conducted numerical simulations of P-, S-, Love and Rayleigh waves propagating through a detailed model of the Larderello-Travale geothermal field based on the known velocity structure. This enables us to identify potential regions where seismic energy may accumulate due to local structure. Results indicate that maximum displacements focus differently when considering body or surface waves. We identify a region located at 3-5 km depth (k-horizon) that may correspond to the brittle-ductile boundary where almost no seismic energy is focused.

  2. Carbon isotope geochemistry of hydrocarbons in the Cerro Prieto geothermal field, Baja California Norte, Mexico.

    Science.gov (United States)

    Des Marais, D J; Stallard, M L; Nehring, N L; Truesdell, A H

    1988-01-01

    Hydrocarbon abundances and stable-isotopic compositions were measured in wells M5, M26, M35 and M102, which represent a range of depths (1270-2000 m) and temperatures (275-330 degrees C) in the field. In order to simulate the production of the geothermal hydrocarbons, gases were collected from the pyrolysis of lignite in the laboratory. This lignite was obtained from a well which sampled rock strata which are identical to those occurring in the field, but which have experienced much lower subsurface temperatures. In both the well and the laboratory observations, high-temperature environments favored higher relative concentrations of methane, ethane and benzene and generally higher delta 13C-values in the individual hydrocarbons. The best correlation between the laboratory and well data is obtained when laboratory-produced gases from experiments conducted at lower (400 degrees C) and higher (600 degrees C) temperatures are mixed. This improved correlation suggests that the wells are sampling hydrocarbons produced from a spectrum of depths and temperatures in the sediments.

  3. Carbon isotope geochemistry of hydrocarbons in the Cerro Prieto geothermal field, Baja California Norte, Mexico

    Science.gov (United States)

    Des Marais, D. J.; Stallard, M. L.; Nehring, N. L.; Truesdell, A. H.

    1988-01-01

    Hydrocarbon abundances and stable-isotopic compositions were measured in wells M5, M26, M35 and M102, which represent a range of depths (1270-2000 m) and temperatures (275-330 degrees C) in the field. In order to simulate the production of the geothermal hydrocarbons, gases were collected from the pyrolysis of lignite in the laboratory. This lignite was obtained from a well which sampled rock strata which are identical to those occurring in the field, but which have experienced much lower subsurface temperatures. In both the well and the laboratory observations, high-temperature environments favored higher relative concentrations of methane, ethane and benzene and generally higher delta 13C-values in the individual hydrocarbons. The best correlation between the laboratory and well data is obtained when laboratory-produced gases from experiments conducted at lower (400 degrees C) and higher (600 degrees C) temperatures are mixed. This improved correlation suggests that the wells are sampling hydrocarbons produced from a spectrum of depths and temperatures in the sediments.

  4. Salton Sea Geothermal Field, California, as a near-field natural analog of a radioactive waste repository in salt

    Energy Technology Data Exchange (ETDEWEB)

    Elders, W.A.; Cohen, L.H.

    1983-11-01

    Since high concentrations of radionuclides and high temperatures are not normally encountered in salt domes or beds, finding an exact geologic analog of expected near-field conditions in a mined nuclear waste repository in salt will be difficult. The Salton Sea Geothermal Field, however, provides an opportunity to investigate the migration and retardation of naturally occurring U, Th, Ra, Cs, Sr and other elements in hot brines which have been moving through clay-rich sedimentary rocks for up to 100,000 years. The more than thirty deep wells drilled in this field to produce steam for electrical generation penetrate sedimentary rocks containing concentrated brines where temperatures reach 365/sup 0/C at only 2 km depth. The brines are primarily Na, K, Ca chlorides with up to 25% of total dissolved solids; they also contain high concentrations of metals such as Fe, Mn, Li, Zn, and Pb. This report describes the geology, geophysics and geochemistry of this system as a prelude to a study of the mobility of naturally occurring radionuclides and radionuclide analogs within it. The aim of this study is to provide data to assist in validating quantitative models of repository behavior and to use in designing and evaluating waste packages and engineered barriers. 128 references, 33 figures, 13 tables.

  5. Mineralogical and Geochemical Constraints on Arsenic Mobility in a Philippine Geothermal Field

    Institute of Scientific and Technical Information of China (English)

    Chelo PASCUA; Tsutomu SATO; Glenn GOLLA

    2006-01-01

    Arsenic is usually associated with sulphide minerals formed in the geothermal environment.However, sulphide minerals are prone to dissolution after contact with meteoric water under surface oxidizing conditions. Secondary precipitates that form from the dissolution of the primary sulfides exert a greater influence on arsenic mobility in the geothermal environment. Fe-hydroxides have very good affinity with dissolved arsenate and are stable under most surface oxidizing conditions. Both amorphous silica directly precipitated from geothermal fluids and possibly a kaolinite alteration can host a small significant amount of arsenic. These silicates are also more stable under a wide range of pH and redox conditions.

  6. Physical properties of two core samples from Well 34-9RD2 at the Coso geothermal field, California

    Science.gov (United States)

    Morrow, C.A.; Lockner, D.A.

    2006-01-01

    The Coso geothermal field, located along the Eastern California Shear Zone, is composed of fractured granitic rocks above a shallow heat source. Temperatures exceed 640 ?F (~338 ?C) at a depth of less than 10000 feet (3 km). Permeability varies throughout the geothermal field due to the competing processes of alteration and mineral precipitation, acting to reduce the interconnectivity of faults and fractures, and the generation of new fractures through faulting and brecciation. Currently, several hot regions display very low permeability, not conducive to the efficient extraction of heat. Because high rates of seismicity in the field indicate that the area is highly stressed, enhanced permeability can be stimulated by increasing the fluid pressure at depth to induce faulting along the existing network of fractures. Such an Enhanced Geothermal System (EGS), planned for well 46A-19RD, would greatly facilitate the extraction of geothermal fluids from depth by increasing the extent and depth of the fracture network. In order to prepare for and interpret data from such a stimulation experiment, the physical properties and failure behavior of the target rocks must be fully understood. Various diorites and granodiorites are the predominant rock types in the target area of the well, which will be pressurized from 10000 feet measured depth (MD) (3048m MD) to the bottom of the well at 13,000 feet MD (3962 m MD). Because there are no core rocks currently available from well 46A-19RD, we report here on the results of compressive strength, frictional sliding behavior, and elastic measurements of a granodiorite and diorite from another well, 34-9RD2, at the Coso site. Rocks cored from well 34-9RD2 are the deepest samples to date available for testing, and are representative of rocks from the field in general.

  7. Testing of the recently developed tectonomagmatic discrimination diagrams from hydrothermally altered igneous rocks of 7 geothermal fields

    OpenAIRE

    PANDARINATH, Kailasa

    2014-01-01

    Recently developed multidimensional tectonomagmatic discrimination diagrams based on log-ratio variables of chemical elements, discordant outlier-free databases, and probability-based boundaries have been shown to work better than the earlier diagrams. Hydrothermally altered drilled well rock cuttings obtained from different depths of geothermal fields were used to test these diagrams to compare the inferred tectonic setting with the expected one. In spite of the hydrothermal alteration effec...

  8. Three-dimensional numerical reservoir simulation of the EGS Demonstration Project at The Geysers geothermal field

    Science.gov (United States)

    Borgia, Andrea; Rutqvist, Jonny; Oldenburg, Curt M.; Hutchings, Lawrence; Garcia, Julio; Walters, Mark; Hartline, Craig; Jeanne, Pierre; Dobson, Patrick; Boyle, Katie

    2013-04-01

    The Enhanced Geothermal System (EGS) Demonstration Project, currently underway at the Northwest Geysers, California, aims to demonstrate the feasibility of stimulating a deep high-temperature reservoir (up to 400 °C) through water injection over a 2-year period. On October 6, 2011, injection of 25 l/s started from the Prati 32 well at a depth interval of 1850-2699 m below sea level. After a period of almost 2 months, the injection rate was raised to 63 l/s. The flow rate was then decreased to 44 l/s after an additional 3.5 months and maintained at 25 l/s up to August 20, 2012. Significant well-head pressure changes were recorded at Prati State 31 well, which is separated from Prati 32 by about 500 m at reservoir level. More subdued pressure increases occur at greater distances. The water injection caused induced seismicity in the reservoir in the vicinity of the well. Microseismic monitoring and interpretation shows that the cloud of seismic events is mainly located in the granitic intrusion below the injection zone, forming a cluster elongated SSE-NNW (azimuth 170°) that dips steeply to the west. In general, the magnitude of the events increases with depth and the hypocenter depth increases with time. This seismic cloud is hypothesized to correlate with enhanced permeability in the high-temperature reservoir and its variation with time. Based on the existing borehole data, we use the GMS™ GUI to construct a realistic three-dimensional (3D) geologic model of the Northwest Geysers geothermal field. This model includes, from the top down, a low permeability graywacke layer that forms the caprock for the reservoir, an isothermal steam zone (known as the normal temperature reservoir) within metagraywacke, a hornfels zone (where the high-temperature reservoir is located), and a felsite layer that is assumed to extend downward to the magmatic heat source. We then map this model onto a rectangular grid for use with the TOUGH2 multiphase, multicomponent, non

  9. Deformation near the Casa Diablo geothermal well field and related processes Long Valley caldera, Eastern California, 1993-2000

    Science.gov (United States)

    Howle, J.F.; Langbein, J.O.; Farrar, C.D.; Wilkinson, S.K.

    2003-01-01

    Regional first-order leveling lines, which extend from Lee Vining, CA, to Tom's Place, CA, have been surveyed periodically since 1957 by the U.S. Geological Survey (USGS), the National Geodetic Survey (NGS), and Caltrans. Two of the regional survey lines, or leveling networks, intersect at the Casa Diablo geothermal well field. These leveling networks, referenced to a distant bench mark (C916) near Lee Vining, provide time-series vertical control data of land-surface deformation that began around 1980. These data are also useful for delineating localized subsidence at Casa Diablo related to reservoir pressure and temperature changes owing to geothermal development that began in 1985. A comparison of differences in bench-mark elevations for five time periods between 1983 and 1997 shows the development and expansion of a subsidence bowl at Casa Diablo. The subsidence coincides spatially with the geothermal well field and temporally with the increased production rates and the deepening of injection wells in 1991, which resulted in an increase in the rate of pressure decline. The subsidence, superimposed on a broad area of uplift, totaled about 310 mm by 1997. The USGS established orthogonal tilt arrays in 1983 to better monitor deformation across the caldera. One tilt array (DBR) was established near what would later become the Casa Diablo geothermal well field. This array responded to magmatic intrusions prior to geothermal development, tilting away from the well field. With the start of geothermal fluid extraction in 1985, tilt at the DBR array reversed direction and began tilting into the well field. In 1991, geothermal power production was increased by a factor of four, and reservoir pressures began a period of steep decline. These changes caused a temporary three-fold increase in the tilt rate. The tilt rate became stable in 1993 and was about 40% lower than that measured in 1991-1992, but still greater than the rates measured during 1985-1990. Data from the

  10. Local and regional seismic response to injection and production at the Salton Sea geothermal field, southern California

    Science.gov (United States)

    Lajoie, L. J.; Brodsky, E. E.

    2011-12-01

    California hosts both the largest geothermal resource capacity and highest seismicity rate in the nation. With plans to increase geothermal output, and proven earthquake triggering in the vicinity of geothermal power plants worldwide, it is important to determine the local and regional effects of geothermal power production. This study focuses on relating the volume of fluid extracted from and re-injected into wells at the Salton Sea geothermal field (SSGF) in Southern California to local seismicity rate and increased probability of larger events on nearby faults such as the San Andreas and Imperial faults. Seismic data is obtained from the publicly available Advanced National Seismic System (ANSS) catalog and SSGF injection and production data from the State of California Department of Conservation. We identify triggered earthquakes in the catalog by modeling seismicity in a 15km radius around the SSGF according to an Epidemic-Type Aftershock Sequence (ETAS) method. The model seeks to fit the cumulative seismicity curve from our dataset by optimizing five seismic parameters in accordance with Gutenberg-Richter and Omori's law. The modeled curve is then removed from the dataset to isolate the non-ETAS, or production-triggered, signal. We then formulate a constitutive law to relate the seismicity rate to the driving stress (i.e. volumetric strain in the reservoir). Defining the local stressing rate provides a tool for predicting the effects that production has on regional seismicity rates. The largest spike in SSGF net production volume over the past 30 years is accompanied by the one of the largest increases in both seismicity rate and moment release within the geothermal field. This indicates a direct coupling between net fluid production volume (volume extracted minus volume re-injected) and seismicity rate and cumulative seismic moment in the field. Three dimensional plots of hypocentral earthquake locations show that seismicity is concentrated on an

  11. The Obsidian Creep Project: Seismic Imaging in the Brawley Seismic Zone and Salton Sea Geothermal Field, Imperial County, California

    Science.gov (United States)

    Catchings, R. D.; Rymer, M. J.; Goldman, M.; Lohman, R. B.; McGuire, J. J.

    2010-12-01

    In March 2010, we acquired medium- and high-resolution P- and S-wave seismic reflection and refraction data across faults in the Brawley seismic zone (BSZ) and across part of the Salton Sea Geothermal Field (SSGF), Imperial Valley, California. Our objectives were to determine the dip, possible structural complexities, and seismic velocities associated with the BSZ and SSGF. We acquired multiple seismic data sets along a north-south profile and a high-resolution P-wave profile along an east-west profile. The north-south profile included: 1) a 6.4-km-long P-wave (main) profile that was recorded on 320 Texan seismographs spaced at 20-m intervals, 2) a 1.2-km-long cabled, high-resolution profile along the northern end of the main profile, and 3) an approximately 1.2-km-long S-wave profile along the cabled profile. P-wave sources along the main profile were generated by 0.15- to 0.45-kg buried explosions spaced every 40 m, and P-wave sources along the cabled profile were generated by Betsy-Seisgun ‘shots’ spaced every 10 m. S-waves sources were generated by hammer impacts on the ends of an aluminum block. The east-west profile consisted of a 3.4-km-long high-resolution P-wave seismic profile with shots (Betsy-Seisgun) and geophones spaced every 10 m. Preliminary interpretation of shot gathers from blasts in the north-south profile suggests that the BSZ and SSGF are structurally complex, with abundant faults extending to or near the ground surface. Also, we observe relatively high-velocity material, apparent velocities of about 4.0 km/s in one direction and about 2.8 km/s in another relative to about 1.6 km/s for shallower material, that shallows beneath the SSGF. This may be due to high temperatures and resultant metamorphism of buried materials in the SSGF. From preliminary interpretation of shot gathers along the east-west profile we interpret a prominent fault that extends to the ground surface. This fault is on projection of the Kalin fault, from about 40 m to

  12. Climate field reconstruction of East Asian spring temperature

    Science.gov (United States)

    Ohyama, M.; Yonenobu, H.; Choi, J.-N.; Park, W.-K.; Hanzawa, M.; Suzuki, M.

    2012-08-01

    We describe a first attempt of dendroclimatic field reconstruction, based upon five ring-width chronologies from living trees, in Japan and Korea. Mean March-May temperature derived from a gridded land air temperature dataset (CRUTEM3) between 35-40° E and 125-140° N was reconstructed for the period of 1784-1990 AD. The reconstruction accounted for 19.4% of the temperature variance in the calibration period. This reconstruction showed remarkably similar fluctuations to regional dendroclimatic reconstructions in Japan and Korea, indicating the past spatial coherency of spring temperatures in the region. The reconstruction was validated against other climate proxies. A fairly good agreement was found with cold periods as estimated from documentary records in China and Japan. The west-Japan temperature series recovered also showed a reasonable agreement with the reconstruction. These comparisons revealed that climatic field reconstruction using tree-ring chronologies in this area offers a good potential for reconstructing long-term and large-scale past temperature patterns for East Asia.

  13. Climate field reconstruction of East Asian spring temperature

    Directory of Open Access Journals (Sweden)

    M. Ohyama

    2012-08-01

    Full Text Available We describe a first attempt of dendroclimatic field reconstruction, based upon five ring-width chronologies from living trees, in Japan and Korea. Mean March–May temperature derived from a gridded land air temperature dataset (CRUTEM3 between 35–40° E and 125–140° N was reconstructed for the period of 1784–1990 AD. The reconstruction accounted for 19.4% of the temperature variance in the calibration period. This reconstruction showed remarkably similar fluctuations to regional dendroclimatic reconstructions in Japan and Korea, indicating the past spatial coherency of spring temperatures in the region. The reconstruction was validated against other climate proxies. A fairly good agreement was found with cold periods as estimated from documentary records in China and Japan. The west-Japan temperature series recovered also showed a reasonable agreement with the reconstruction. These comparisons revealed that climatic field reconstruction using tree-ring chronologies in this area offers a good potential for reconstructing long-term and large-scale past temperature patterns for East Asia.

  14. Geothermal handbook. Geothermal project, 1976. [Ecological effects of geothermal resources development

    Energy Technology Data Exchange (ETDEWEB)

    1976-06-01

    The geothermal program of Fish and Wildlife Service, U.S. Dept. of Interior, aims to develop ecologically sound practices for the exploration, development, and management of geothermal resources and the identification of the biological consequences of such development so as to minimize adverse effects on fish and wildlife resources. This handbook provides information about the ecological effects of geothermal resource development. Chapters are included on US geothermal resources; geothermal land leasing; procedures for assessing the effects on fish and game; environmental impact of exploratory and field development operations; and wildlife habitat improvement methods for geothermal development.

  15. Hyperspectral image analysis for the determination of alteration minerals in geothermal fields: Çürüksu (Denizli) Graben, Turkey

    Science.gov (United States)

    Uygur, Merve; Karaman, Muhittin; Kumral, Mustafa

    2016-04-01

    Çürüksu (Denizli) Graben hosts various geothermal fields such as Kızıldere, Yenice, Gerali, Karahayıt, and Tekkehamam. Neotectonic activities, which are caused by extensional tectonism, and deep circulation in sub-volcanic intrusions are heat sources of hydrothermal solutions. The temperature of hydrothermal solutions is between 53 and 260 degree Celsius. Phyllic, argillic, silicic, and carbonatization alterations and various hydrothermal minerals have been identified in various research studies of these areas. Surfaced hydrothermal alteration minerals are one set of potential indicators of geothermal resources. Developing the exploration tools to define the surface indicators of geothermal fields can assist in the recognition of geothermal resources. Thermal and hyperspectral imaging and analysis can be used for defining the surface indicators of geothermal fields. This study tests the hypothesis that hyperspectral image analysis based on EO-1 Hyperion images can be used for the delineation and definition of surfaced hydrothermal alteration in geothermal fields. Hyperspectral image analyses were applied to images covering the geothermal fields whose alteration characteristic are known. To reduce data dimensionality and identify spectral endmembers, Kruse's multi-step process was applied to atmospherically and geometrically-corrected hyperspectral images. Minimum Noise Fraction was used to reduce the spectral dimensions and isolate noise in the images. Extreme pixels were identified from high order MNF bands using the Pixel Purity Index. n-Dimensional Visualization was utilized for unique pixel identification. Spectral similarities between pixel spectral signatures and known endmember spectrum (USGS Spectral Library) were compared with Spectral Angle Mapper Classification. EO-1 Hyperion hyperspectral images and hyperspectral analysis are sensitive to hydrothermal alteration minerals, as their diagnostic spectral signatures span the visible and shortwave

  16. Modelling the Interaction of Multiple Borehole Heat Exchangers in Shallow Geothermal Fields

    Science.gov (United States)

    Shao, H.; Schelenz, S.; Kist, N.; Shim, B. O.; Bucher, A.; Kolditz, O.

    2014-12-01

    The utilization of Borehole Heat Exchanger (BHE) to transfer heat from the shallow subsurface has been a common practice for the Ground Source Heat Pump (GSHP) system. To represent realistic application scenarios for numerical simulations of such systems, saturated and unsaturated conditions as well as heterogeneous soil properties have to be considered. Analytical solutions such as the Moving Finite Line Source (MFLS) model are not flexible enough to capture the full dynamics of the system. Furthermore, application examples with a high density of installed BHEs exist. There, temperature plumes produced by the individual BHEs may start to interact with each other and lead to lower thermal output. To simulate this interaction, a dual continuum approach has been implemented into the open-source FEM simulator OpenGeoSys (OGS). The model is capable of simulating the temperature evolution around the BHE, with the consideration of both saturated and unsaturated groundwater flow processes in the surrounding soil. Instead of imposing Dirichlet or Neumann type of boundary condition at the location of a BHE, the newly developed model allows the user to specify inflow refrigerant temperature and flow rate as the driving force of heat transport. In a benchmark with homogeneous soil properties and fully saturated condition, temperature evolution predicted by the numerical model has been verified against MFLS analytical solution. In a second benchmark, the model simulated outflow temperature is validated by comparing to field measured data from a Thermal Response Test (TRT), provided by the Korean Institute of Geoscience and Mineral Resources (KIGAM) in Dajeon, South Korea. After simulating several shallow geothermal scenarios of multiple BHEs operating in close vicinity, we find that the super-imposed MFLS based analytical solution predicts similar temperature distribution, provided the heat extraction from each BHE is relatively low. However, when the heat exchange rate is

  17. Integrated Geophysical Exploration Program at the Rye Patch Geothermal Field, Pershing County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    W. Teplow

    1999-09-01

    The purpose of the geophysical exploration program was to use an integrated suite of detailed geophysical surveys to locate and map commercially productive zones in the Rye Patch geothermal field. The focus of the surveys was the production zone in Well 44-28 located at a depth of 3400' below surface. The primary goal of the program was to map the extension of the specific producing feature in 44-28 so that step-out wells could be targeted accurately. The second goal of the program was to identify additional production drilling targets that may be hydrologically independent from the 44-28 zone. The geophysical program was designed to measure a range of physical rock characteristics including magnetic, electrical, density, and sonic properties. This was done to help overcome the limitations and ambiguities inherent to any particular geophysical method. The studies and methodologies employed in the Rye Patch geophysical program are discussed. This report presents the results and a discussion of those results from each of the surveys and studies performed. Correlations among the data sets and between the data sets and the known producing zones are discussed, and drilling targets are presented as the end product of the correlations observed in the geophysical and geologic data.

  18. Dynamic triggering of microearthquakes in the Long Valley Caldera and Coso Geothermal Field

    Science.gov (United States)

    Aiken, C.; Peng, Z.; Wu, C.

    2010-12-01

    Recent studies have shown that microearthquakes can be dynamically triggered by the passing of surface waves from regional and teleseismic events. However, the underlying physical mechanisms and the necessary conditions that favor dynamic triggering are still in debate. Here we conduct a systematic search of dynamically triggered microearthquakes around the Long Valley Caldera (LVC) and Coso Geothermal Field (CGF) in California. In each region, we select distant mainshocks in 1999-2010 with M>=7.5 over 1000 km away, or M>=5.5 between 100-2500 km. Next, we apply 2-8 or 2-16 Hz band-pass-filtered data to the three-component seismograms recorded at each region, and identify triggered events as high-frequency seismic energy during large-amplitude surface waves of regional and teleseismic events. We calculate the beta statistic values based on events listed in the local earthquake catalogs and hand-picked events from the envelope functions, and verify that the triggering is statistically significant. Based on this simple procedure, we have identified many distant events that have triggered activity in both regions, including the recent 08/03/2009 and 04/04/2010 Baja California earthquakes at regional distances, and the 02/27/2010 Chile earthquake at teleseismic distances. Our next steps are to examine the dynamic triggering thresholds in each region, and to understand the triggering potential in terms of frequency, amplitude, incident angle, and type of surface waves.

  19. The impact of temperature on microbial diversity and AOA activity in the Tengchong Geothermal Field, China.

    Science.gov (United States)

    Li, Haizhou; Yang, Qunhui; Li, Jian; Gao, Hang; Li, Ping; Zhou, Huaiyang

    2015-11-26

    Using a culture-independent method that combines CARD-FISH, qPCR and 16S rDNA, we investigated the abundance, community structure and diversity of microbes along a steep thermal gradient (50-90 °C) in the Tengchong Geothermal Field. We found that Bacteria and Archaea abundance changed markedly with temperature changes and that the number of cells was lowest at high temperatures (90.8 °C). Under low-temperature conditions (52.3-74.6 °C), the microbial communities were dominated by Bacteria, which accounted for 60-80% of the total number of cells. At 74.6 °C, Archaea were dominant, and at 90.8 °C, they accounted for more than 90% of the total number of cells. Additionally, the microbial communities at high temperatures (74.6-90.8 °C) were substantially simpler than those at the low-temperature sites. Only a few genera (e.g., bacterial Caldisericum, Thermotoga and Thermoanaerobacter, archaeal Vulcanisaeta and Hyperthermus) often dominated in high-temperature environments. Additionally, a positive correlation between Ammonia-Oxidizing Archaea (AOA) activity and temperature was detected. AOA activity increased from 17 to 52 pmol of NO2(-) per cell d(-1) with a temperature change from 50 to 70 °C.

  20. Arsenic speciation in sinter mineralization from a hydrothermal channel of El Tatio geothermal field, Chile

    Science.gov (United States)

    Alsina, Marco A.; Zanella, Luciana; Hoel, Cathleen; Pizarro, Gonzalo E.; Gaillard, Jean-François; Pasten, Pablo A.

    2014-10-01

    El Tatio geothermal field is the principal natural source of arsenic for the Loa River, the main surface water resource in the hyper-arid Atacama Desert (Antofagasta Region, Northern Chile). Prior investigations by bulk X-ray absorption spectroscopy have identified hydrous ferric oxides as the principal arsenic-containing phase in sinter material from El Tatio, suggesting sorption as the main mechanism for arsenic scavenging by the solid phases of these hot spring environments. Here we examine siliceous sinter material sampled from a hydrothermal channel using synchrotron based X-ray micro-probe techniques, including As and Fe Kα X-ray fluorescence (μ-XRF), As K-edge X-ray absorption near edge structure (μ-XANES), and X-ray diffraction (μ-XRD). Least-squares linear fitting of μ-XANES spectra shows that arsenic is predominantly present as arsenate sorbed on hydrous ferric oxides (63% molar proportion), but we also identify nodular arsenide micro-mineralizations (37% molar proportion) similar to loellingite (FeAs2), not previously detected during bulk-scale analysis of the sinter material. Presence of arsenide mineralizations indicates development of anoxic environments on the surface of the siliceous sinter, and suggests a more complex biogeochemistry for arsenic than previously observed for circum-neutral pH brine hot spring environments.

  1. Fault rock mineralogy and fluid flow in the Coso Geothermal Field, CA

    Science.gov (United States)

    Davatzes, N. C.; Hickman, S. H.

    2005-12-01

    The minerals that comprise fault rock, their grain shapes, and packing geometry are important controls on fault zone properties such as permeability, frictional strength, and slip behavior. In this study we examine the role of mineralogy and deformation microstructures on fluid flow in a fault-hosted, fracture-dominated geothermal system contained in granitic rocks in the Coso Geothermal Field, CA. Initial examination of the mineralogy and microstructure of fault rock obtained from core and surface outcrops reveals three fault rock types. (1) Fault rock consisting of kaolinite and amorphous silica that contains large connected pores, dilatant brittle fractures, and dissolution textures. (2) Fault rock consisting of foliated layers of chlorite and illite-smectite separated by slip surfaces. (3) Fault rock consisting of poorly sorted angular grains, characterized by large variations in grain packing (pore size), and crack-seal textures. These different fault rocks are respectively associated with a high permeability upper boiling zone for the geothermal system, a conductively heated "caprock" at moderate to shallow depth associated with low permeability, and a deeper convectively heated region associated with enhanced permeability. Outcrop and hand-sample scale mapping, XRD analysis, and SEM secondary electron images of fault gouge and slip surfaces at different stages of development (estimated shear strain) are used to investigate the processes responsible for the development and physical properties of these distinct fault rocks. In each type of fault rock, mineral dissolution and re-precipitation in conjunction with the amount and geometry of porosity changes induced by dilation or compaction are the key controls on fault rock development. In addition, at the contacts between slip surfaces, abrasion and resulting comminution appear to influence grain size, sorting, and packing. Macroscopically, we expect the frictional strength of these characteristic fault rocks

  2. Fracture development within a stratovolcano: The Karaha-Telaga Bodas geothermal field, Java volcanic arc

    Science.gov (United States)

    Nemcok, M.; Moore, J.N.; Allis, R.; McCulloch, J.

    2004-01-01

    Karaha-Telaga Bodas, a vapour-dominated geothermal system located in an active volcano in western Java, is penetrated by more than two dozen deep geothermal wells reaching depths of 3 km. Detailed paragenetic and fluid-inclusion studies from over 1000 natural fractures define the liquid-dominated, transitional and vapour-dominated stages in the evolution of this system. The liquid-dominated stage was initiated by ashallow magma intrusion into the base of the volcanic cone. Lava and pyroclastic flows capped a geothermal system. The uppermost andesite flows were only weakly fractured due to the insulating effect of the intervening altered pyroclastics, which absorbed the deformation. Shear and tensile fractures that developed were filled with carbonates at shallow depths, and by quartz, epidote and actinolite at depths and temperatures over 1 km and 300??C. The system underwent numerous cycles of overpressuring, documented by subhorizontal tensile fractures, anastomosing tensile fracture patterns and implosion breccias. The development of the liquidsystem was interrupted by a catastrophic drop in fluid pressures. As the fluids boiled in response to this pressure drop, chalcedony and quartz were selectively deposited in fractures that had the largest apertures and steep dips. The orientations of these fractures indicate that the escaping overpressured fluids used the shortest possible paths to the surface. Vapour-dominated conditions were initiated at this time within a vertical chimney overlying the still hot intrusion. As pressures declined, these conditions spread outward to form the marginal vapour-dominated region encountered in the drill holes. Downward migration of the chimney, accompanied by growth of the marginal vapour-dominated regime, occurred as the intrusion cooled and the brittle-ductile transition migrated to greater depths. As the liquids boiled off, condensate that formed at the top of the vapour-dominated zone percolated downward and low

  3. Gas and Isotope Geochemistry of 81 Steam Samples from Wells in The Geysers Geothermal Field, Sonoma and Lake Counties, California

    Science.gov (United States)

    Lowenstern, Jacob B.; Janik, Cathy J.; Fahlquist, Lynne; Johnson, Linda S.

    1999-01-01

    The Geysers geothermal field in northern California, with about 2000-MW electrical capacity, is the largest geothermal field in the world. Despite its importance as a resource and as an example of a vapor-dominated reservoir, very few complete geochemical analyses of the steam have been published (Allen and Day, 1927; Truesdell and others, 1987). This report presents data from 90 steam, gas, and condensate samples from wells in The Geysers geothermal field in northern California. Samples were collected between 1978 and 1991. Well attributes include sampling date, well name, location, total depth, and the wellhead temperature and pressure at which the sample was collected. Geochemical characteristics include the steam/gas ratio, composition of noncondensable gas (relative proportions of CO2, H2S, He, H2, O2, Ar, N2, CH4, and NH3), and isotopic values for deltaD and delta18O of H2O, delta13C of CO2, and delta34S of H2S. The compilation includes 81 analyses from 74 different production wells, 9 isotopic analyses of steam condensate pumped into injection wells, and 5 complete geochemical analyses on gases from surface fumaroles and bubbling pools. Most samples were collected as saturated steam and plot along the liquid-water/steam boiling curve. Steam-togas ratios are highest in the southeastern part of the geothermal field and lowest in the northwest, consistent with other studies. Wells in the Northwest Geysers are also enriched in N2/Ar, CO2 and CH4, deltaD, and delta18O. Well discharges from the Southeast Geysers are high in steam/gas and have isotopic compositions and N2/Ar ratios consistent with recharge by local meteoric waters. Samples from the Central Geysers show characteristics found in both the Southeast and Northwest Geysers. Gas and steam characteristics of well discharges from the Northwest Geysers are consistent with input of components from a high-temperature reservoir containing carbonrich gases derived from the host Franciscan rocks. Throughout the

  4. Fracture network, fluid pathways and paleostress at the Tolhuaca geothermal field

    Science.gov (United States)

    Pérez-Flores, Pamela; Veloso, Eugenio; Cembrano, José; Sánchez-Alfaro, Pablo; Lizama, Martín; Arancibia, Gloria

    2017-03-01

    In this study, we examine the fracture network of the Tolhuaca geothermal system located in the Southern Andean volcanic zone that may have acted as a pathway for migration and ascent of deep-seated fluids under the far/local stress field conditions of the area. We collected the orientation, slip-data and mineralogical content of faults and veins recovered on a ca. 1000 m deep borehole (Tol-1) located in the NW-flank of the Tolhuaca volcano. Tol-1 is a non-oriented, vertical borehole that recovered relatively young (examined and measured the inclination, geometry, texture, mineralogy, and relative sense of displacement of veins and faults. To determine the actual azimuthal orientation of fault and veins we reoriented 66 segments (89 standard mini-cores) of Tol-1 using stable Characteristic remanent magnetization component (ChRM) obtained by thermal demagnetization methodology. Paleo-declination of ChRM vectors was used to re-orient the borehole pieces, as well as fault and veins, to a common anchor orientation value consistent with the Geocentric Axial Dipole approximation (GAD). Inversion of RM-corrected fault-slip data reveals a local tensional stress field with a vertically oriented σ1 axis (083/74) and a subhorizontal, NS-trending σ3 axis (184/03). Within the topmost 400 m of the borehole, faults and veins are randomly oriented, whereas below 400 m depth, faults and veins show preferential NE-to EW-strikes and steep (>50°) dips. The EW-striking veins are compatible with the calculated local stress field whereas NE-striking veins are compatible with the regional stress field, the morphological elongation of volcanic centers, alignments of flank vents and dikes orientation. Our results demonstrate that the paleomagnetic methodology proved to be reliable and it is useful to re-orient vertical boreholes such as Tol-1. Furthermore, our data show that the bulk transpressional regional stress field has local variations to a tensional stress field within the NE

  5. Effect of variable frequency electromagnetic field on deposit formation in installations with geothermal water in Sijarinjska spa (Serbia

    Directory of Open Access Journals (Sweden)

    Stojiljković Dragan T.

    2011-01-01

    Full Text Available In this paper we have examined the effect of variable frequency electromagnetic field generated with a homemade device on deposit formation in installations with geothermal water from Sijarinjska Spa. The frequency alteration of the electromagnetic field in time was made by means of the sinusoidal and saw-tooth function. In laboratory conditions, with the flow of geothermal water at 0.015 l/s and temperature of 60 °C for 6 hours through a zig-zag glass pipe, a multiple decrease of total deposit has been achieved. By applying the saw-tooth and sinusoidal function, the decrease in contents of calcium and deposit has been achieved by 8 and 6 times, respectively. A device was also used on geothermal water installation in Sijarinjska Spa (Serbia, with the water flow through a 1'' diameter non-magnetic prochrome pipe at 0.15 l/s and temperature of 75 °C in a ten-day period. A significant decrease in total deposit and calcium in the deposit has also been achieved.

  6. SolGeo. A new computer program for solute geothermometers and its application to Mexican geothermal fields

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Surendra P.; Pandarinath, Kailasa; Santoyo, Edgar [Departamento de Sistemas Energeticos, Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Priv. Xochicalco s/no., Col Centro, A.P. 34, Temixco, Mor. 62580 (Mexico)

    2008-12-15

    The freely available computer program Solute Geothermometers (SolGeo) was written and tested using geochemical data and reported geothermometric temperatures from several geothermal wells from around the world. Subsurface temperatures for the Mexican geothermal fields of Cerro Prieto, Las Tres Virgenes, Los Azufres, and Los Humeros were estimated based on different solute geothermometers and found to be generally in close agreement with measured well temperatures when considering errors in the calculations and measurements. For Los Humeros wells it was concluded that a better agreement of chemical geothermometric temperatures is observed with static formation than with bottom-hole temperatures (BHTs). It was also found that the widely used Na-K geothermometric equations generally give more consistent and more reliable temperature estimates than the other geothermometers, which should therefore be applied with caution. (author)

  7. Simulation studies for wells AH-4bis/AH-17 and AH-18, Ahuachapan Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Monterrosa, Manuel Ernesto

    1996-01-24

    Well AH-4bis, at the Ahuachapan Geothermal Field is planned to be drilled on the same pad as the former AH-4. A simulation study was carried out for two casing dameters 13 5/8 and 9 5/8” in order to estimate its production and to know its economic feasibility. The simulation results indcate a high probability of production in the range of 7 Mwe, equivalent to 120 kg/s total mass flow rate, 1250 kJ/kg at 6 bar-a for the new well AH-4bis. Well AH- 17 is good producer, during 1991 after ten years of production, the well was shut-in due to silica scaling problems. A wellbore simulation was carried out in order to predict the new production conditions after the work-over, mainly to estimate the water flow rate in order to reduce the silica scaling. The results indicate a very low water flow rate. The match between the simulated and measured production curves after the work-over was successful. The well AH-18 is located at the southern part of the actual bore field. CEL is planning to expand the borefield at this area and it is neccessary to estimate the possible production condtions at that zone. The results indicate a high probabilty of production at that area. The power potential is estimated at 3.5 Mwe per well at WHP 6 bar-a and the wells will not require induction.

  8. Determination of Microbial Diversity and Nitrogen Cycling from Kizildere Geothermal Field with Next Generation Sequencing

    Science.gov (United States)

    Gulecal, Y.; Dilek, Y.

    2012-12-01

    The deep terrestrial subsurface biosphere represents an emerging frontier for studies of biodiversity, the physiological limits to life, microbial mechanisms of adaptation, and potentially analogous environments for extraterrestrial life (1). Last decade, researches of deep boreholes in the United States, Finland, Sweden, Japan and South Africa, using molecular tools, have shown an an active biosphere composed of diverse groups of microorganisms. The microbial communities reported from different subsurface communities vary widely; such differences are due to different host rock types and varied water origins and chemistry, as well as geography. Furthermore, nitrogen cycling is studied intensely in hot springs for instance in situ nifH expression in Yellowstone National Park, is a new upper temperature limit for nitrogen fixation in alkaline, terrestrial hydrothermal environments (2). This study explores the genetic diversity of microbial communities and genes of nitrogen cycling in Kizildere Geothermal Field, Turkey. The Kizildere thermal waters are located in the northern part of the Büyük Menderes rift zone. The hydrothermal alteration includes phyllic, argillic, silicic,hematitized, and carbonatized alteration zones. The surface temperatures of Kizildere thermal waters in drill holes range from 95 to100°C and pH 9.0-9.5. Microbial communities were examined using culture independent methods, next generation sequencing. Nitrogen fixation, the diversity of nifH, ammonia oxidation (amoA), narG, nosZ genes are investigated in deeply-sourced fluids. We present field observations and interpret new data, establishing a geobiological baseline for previously undescribed sitres of subsurface ecosystems. (1)Fredrickson et al. 2006. Geomicrobial processes and biodiversity in the deep terrestrial subsurface. Geomicrobiology J. 23:345-356. (2) Loiacono et al. 2012. Evidence for high-temperature in situ nifH transcription in an alkaline hot spring of Lower Geyser Basin

  9. MESA/MEP at American River College: Year One Evaluation Report.

    Science.gov (United States)

    Lee, Beth S.; And Others

    In 1989, the Mathematics, Engineering, and Science Achievement (MESA)/Minority Engineering Program (MEP) was initiated at American River College. The MESA/MEP program recruits Black, Hispanic, and Native American students and provides assistance, encouragement, and enrichment programs to help them succeed in the fields of mathematics, engineering,…

  10. An integrated deep electrical resistivity model of the Larderello geothermal field (Italy)

    Science.gov (United States)

    Rizzo, Enzo; Capozzoli, Luigi; De martino, Gregory; Godio, Alberto; Manzella, Adele; Perciante, Felice; Santilano, Alessandro

    2017-04-01

    A new deep electrical resistivity acquisition was carried out in Larderello geothermal area (Tuscania Region, Italy) by 3D Deep Electrical Resistivity Tomography (3D-DERT) and Magnetotelluric (M) acquisition. The investigated area is located close the Venelle2 well in the southern part of Larderello site, where there is the oldest field in the world under exploitation for power production (actual installed capacity is about 795 MWe). A vapour-dominated system is exploited to depth over 3500 m, with temperatures exceeding 350°C, from two different reservoirs. The Larderello area has been investigated by many geological and geophysical data of previous exploration projects but nowadays several critical issues on deep features of the field are still matter of debate, e.g., permeability distribution in the hydrothermal reservoir and the presence of fluids at supercritical condition at depth. The 3D-DERT system was designed by Surface-Surface and Surface-Hole electrode distributions in the area around Venelle2 well covering an area around 16km2. The well (kindly provided by Enel GP) was accessible down to 1.6 km with a temperature up to 250°C and a metallic casing down to 1 km. The in-hole thermal cable is characterized by n.12 flexible metallic electrodes with an electrodes space of 50m covering the open-hole portion (1050m-1600m). The surface electrodes are located around the Venelle2 hole on n.23 different positions connected to automatic dataloger to acquire the drop of potential and to transmitter device to inject the current (5-10A). The crucial task was the data processing, considering the large distance between the Tx and Rx systems that strongly reduces the signal to-noise ratio. To overcome this drawback, for each quadripole position the corresponding voltage signal was filtered, stored and processed with advanced statistical packages. The new 22 station were installed in the studied area and the data were carried out taking in account a permanent remote

  11. Micro-seismicity, fault structure, and hydrologic compartmentalization within the Coso Geothermal Field, California, from 1996 until present

    Science.gov (United States)

    Kaven, J. O.; Hickman, S.; Davatzes, N. C.

    2010-12-01

    Geothermal reservoirs derive their capacity for fluid and heat transport in large part from faults and fractures. In conventional reservoirs, preexisting faults and fractures are the main conduits for fluid flow, while in enhanced geothermal systems (EGS), fractures and faults that are generated or enlarged (i.e., through increases in surface area and aperture) by hydraulic stimulation provide the main pathways for fluids and heat. In both types of geothermal systems, seismicity can be used to locate active faults, which can act either as conduits for along-fault fluid flow and/or barriers to cross-fault flow. We relocate 14 years of seismicity in the Coso Geothermal Field (CGF) using differential travel time relocations to improve our knowledge of the subsurface geologic and hydrologic structure. The seismicity at Coso has been recorded on a local network operated by the Navy Geothermal Program, which provides exceptional coverage and quality of data. Using the relocated catalog, we employ a newly developed algorithm for fault identification using the spatial seismicity distribution and a priori constraints on fault zone width derived from local geologic mapping. We avoid having to assume a particular fault-normal seismicity distribution by finding regions of maximum spatial seismicity density. Assuming a maximum spatial density is physically plausible since faults, or more accurately fault zones, generate most of the associated seismicity within a central fault core or damage zone. These techniques are developed for naturally occurring, active faults within the CGF on which seismicity is induced, in part, by changes in production and injection. They can also be applied to EGS if seismicity is induced within newly created fracture systems of comparable width or if this seismicity is generated by stimulating pre-existing, partially sealed faults. The results of the relocations reveal that clouds of seismicity shrink into distinct oblate volumes of seismicity in

  12. Environmental summary document for the Republic Geothermal, Inc. application for a geothermal loan guaranty project: 64 MW well field and 48 MW (net) geothermal power plant

    Energy Technology Data Exchange (ETDEWEB)

    Layton, D.W.; Powers, D.J.; Leitner, P.; Crow, N.B.; Gudiksen, P.H.; Ricker, Y.E.

    1979-07-01

    A comprehensive review and analysis is provided of the environmental consequences of (1) guaranteeing a load for the completion of the 64 MW well field and the 48 MW (net) power plant or (2) denying a guaranteed load that is needed to finish the project. Mitigation measures are discussed. Alternatives and their impacts are compared and some discussion is included on unavoidable adverse impacts. (MHR)

  13. Hydrochemical characteristics and isotope analysis of geothermal water in Liangxiang geothermal field%良乡地热田地热水化学特征及同位素分析

    Institute of Scientific and Technical Information of China (English)

    刘颖超; 刘凯; 孙颖; 刘久荣; 郭高轩

    2015-01-01

    According to the geothermal settings,hydrochemical data,and research on the isotopes ofδD,δ 1 8 O,3 H,1 4 C in geother-mal water in the Liangxiang geothermal field,the origin,metamorphism and evolution,and hydrological characteristics of iso-topes of geothermal water were investigated.The results suggested that (1)the hydrochemistry type of geothermal water in the Liangxiang geothermal field is mainly HCO3 ·SO4-Ca·Na·Mg,and the geothermal water contains mineral components with medical benefits,especially chlorine and metasilicic acid;(2)according to the analysis of ion concentrations,the geothermal wa-ter is lixiviated and belongs to initially metamorphic water;(3)the geothermal water is immature based on the water-rock bal-ance status;(4)the geothermal water is mainly formed by the mixing of geothermal heat source water and modern circulating water supply from the southwest of Beijing multiphase fault-subsidence;(5)the age of geothermal water is about 38 960±630 years based on the isotope analysis of 3 H and 1 4 C;and (6)the recharge elevation of the geothermal water is about 620 to 730 m according to the stable isotope calculations of oxygen and hydrogen,and the recharge source is the mountain area with relatively lower elevations in the southwest of Beijing.%通过对良乡地热田中地热地质条件、地热水化学资料及δD、δ18 O、3 H、14 C同位素的研究,阐述了良乡地热田地热水的起源、地热水的变质与演化、同位素水文特征。研究表明:良乡地热田中地热水化学类型以 HCO3· SO4-Ca·Na·Mg 型为主,同时地热水中含有氟、偏硅酸等多种有医疗价值的特殊组分;通过对地热水离子浓度分析,良乡地热田中地热水具有入渗溶滤水特征,为初期变质水。从水-岩平衡状态上看,地热田中地热水为未成熟水;依据主要离子浓度和同位素分析,良乡地热田中地热水为地热热源水和来自北京迭断陷西南方向现代循环水补

  14. Characterization of injection wells in a fractured reservoir using PTS logs, Steamboat Hills Geothermal Field, Nevada, USA

    Energy Technology Data Exchange (ETDEWEB)

    Goranson, Colin; Combs, Jim

    1995-01-26

    The Steamboat Hills Geothermal Field in northwestern Nevada, about 15 km south of Reno, is a shallow (150m to 825m) moderate temperature (155 C to 168 C) liquid-dominated geothermal reservoir situated in highly-fractured granodiorite. Three injection wells were drilled and completed in granodiorite to dispose of spent geothermal fluids from the Steamboat II and III power plants (a 30 MW air-cooled binary-type facility). Injection wells were targeted to depths below 300m to inject spent fluids below producing fractures. First, quasi-static downhole pressure-temperature-spinner (PTS) logs were obtained. Then, the three wells were injection-tested using fluids between 80 C and 106 C at rates from 70 kg/s to 200 kg/s. PTS logs were run both up and down the wells during these injection tests. These PTS surveys have delineated the subsurface fracture zones which will accept fluid. The relative injectivity of the wells was also established. Shut-in interzonal flow within the wells was identified and characterized.

  15. Geothermal field and its relation with coalbed methane distribution of the Qinshui Basin

    Institute of Scientific and Technical Information of China (English)

    SUN Zhanxue; ZHANG Wen; HU Baoqun; LI Wenjuan; PAN Tianyou

    2005-01-01

    The average geothermal gradient in the Qinshui Basin, Shanxi Province, North China, estimated from temperature logging data of 20 boreholes is 28.2±1.03℃/km.The thermal conductivities of 39 rock samples are measured and 20 heat flow values are obtained. The estimated heat flow ranges from 44.75 mW/m2 to 101.81 mW/m2, with a mean of 62.69±15.20 mW/m2. The thermal history reconstruction from the inversion of vitrinite data, using Thermodel for Windows 2004, reveals that the average paleo-heat flow at the time of maximum burial in late Jurassic to early Cretaceous is 158.41 mW/m2 for the north part, 119.57mW/m2 for the central part and 169.43 mW/m2 for the south part of the basin respectively. The reconstruction of the buried history of the strata indicates that the age for the end of sedimentation and the beginning of erosion for the basin is 108-156 Ma, and that the eroded thickness of the strata is 2603 m in the north, 2291 m in the central, and 2528.9 m in the south of the basin respectively. The "higher in the north and the south, lower in the central" distribution pattern of the paleo-heat flow coincides with the distribution of the coal-bed methane spatially and temporally, which shows that the coal-bed methane is controlled by the paleo-geotemperature field in the basin.

  16. Development of geothermal field following the 2000 eruption of Usu volcano as revealed by ground temperature, resistivity and self-potential variations

    Directory of Open Access Journals (Sweden)

    T. Mogi

    2007-06-01

    Full Text Available The 2000 eruption of Usu volcano, NE Japan, took place on the foot of the somma, and formed a cryptodome of 65 m high accompanying numerous faults. We made repeated measurements of ground temperature, Self-Potential (SP and electrical resistivity, in order to clarify the mechanism of development of the newly formed geothermal field on the fault zone. Prior to the expansion of the geothermal field, we detected a resistive zone at the center of the geothermal zone and it supposed to evidence that the zone involving dry steam phase had been formed beneath the fault zone. A rapid expansion of the geothermal field followed along the fault zone away from the craters. The place of maximum amplitude of the SP field also migrated following the expansion of the high ground temperature zone. The high resistive part has shrunk as a consequence of the progress of condensation to warm the surroundings. Based on the observations, we delineated the process of the hydrothermal circulation. Considering the topographic effect of the SP field observed on the highly permeable zone in the Usu somma, the potential flow along the slope of the soma was expected to play an important role to promote the rapid expansion of the geothermal field and the migration of the most active part.

  17. Gas Geothermometry in the Hveragerdi High—Temperature Geothermal Field,SW Iceland

    Institute of Scientific and Technical Information of China (English)

    孙占学; HALLDORARMANNSON

    2000-01-01

    Five gas geothermometers based on the concentrations of CO2,H2S,H2,CH2,N2 and Ar in fumaroles and wet-stem wells are applied to estimating subsurface temperatures in the Hveragerdi high-temperature geothmal field,SW Iceland,The results for fumaroles indicate that the calculated subsurface temperatures decrase from the northern part to the southern part of the field.The CO2-geothermometer gives the highers temperature values,with an average of 256℃ for the northern part,and 247℃ for the southern part.The H2S-geothermometer reveals an aquifer temperature of 211℃ for the northern part,and 203℃ for the southern part.The H2-geothermometer gives an average subsurface temperature of 229℃ for the northern part,and 184℃ for the southern part,which agerees excellently with the measured temperatures in wet-steam wells.The measured borhole temperatures in the field range from 215℃ to 230℃ for the northern part,and from 167℃ to 198℃ for the southern part.The CO2/H2-geothermometer gives the lowest subsurface temperature values,with an average of 203℃ for the northern part,and 143℃ for the southern part,The CO2/N2-geothermometer gives 249℃ for the northern part and 235℃ for the southern part.For the data from wells,the CO2-, H2S-,and H2-geothermometers,give average subsurface temperatures of 247℃ for the northern part and 246℃ for the southern part,213℃ for the northern part and 220℃ for the southern part,and 217℃ for the northern part and 216℃ for the southern part,respectively.The CO2/H2-geothermometer indicates an average subsurface tem,perature of about 200℃ for both the northern part and the southern part.The CO2/N2-geothermometer gives an average subsurface temperature of 180℃ for the northern part and 259℃ for the southern part.The discrepancy between the estimeated subsurface temperatures obtained by the various gas geothermometers has been explained in this paper.By integrating the solute geothermometric results,mixing model

  18. Causality between expansion of seismic cloud and maximum magnitude of induced seismicity in geothermal field

    Science.gov (United States)

    Mukuhira, Yusuke; Asanuma, Hiroshi; Ito, Takatoshi; Häring, Markus

    2016-04-01

    Occurrence of induced seismicity with large magnitude is critical environmental issues associated with fluid injection for shale gas/oil extraction, waste water disposal, carbon capture and storage, and engineered geothermal systems (EGS). Studies for prediction of the hazardous seismicity and risk assessment of induced seismicity has been activated recently. Many of these studies are based on the seismological statistics and these models use the information of the occurrence time and event magnitude. We have originally developed physics based model named "possible seismic moment model" to evaluate seismic activity and assess seismic moment which can be ready to release. This model is totally based on microseismic information of occurrence time, hypocenter location and magnitude (seismic moment). This model assumes existence of representative parameter having physical meaning that release-able seismic moment per rock volume (seismic moment density) at given field. Seismic moment density is to be estimated from microseismic distribution and their seismic moment. In addition to this, stimulated rock volume is also inferred by progress of microseismic cloud at given time and this quantity can be interpreted as the rock volume which can release seismic energy due to weakening effect of normal stress by injected fluid. Product of these two parameters (equation (1)) provide possible seismic moment which can be released from current stimulated zone as a model output. Difference between output of this model and observed cumulative seismic moment corresponds the seismic moment which will be released in future, based on current stimulation conditions. This value can be translated into possible maximum magnitude of induced seismicity in future. As this way, possible seismic moment can be used to have feedback to hydraulic stimulation operation in real time as an index which can be interpreted easily and intuitively. Possible seismic moment is defined as equation (1), where D

  19. Composition and origin of rhyolite melt intersected by drilling in the Krafla geothermal field, Iceland

    Science.gov (United States)

    Zierenberg, R.A.; Schiffman, P.; Barfod, G.H.; Lesher, C.E.; Marks, N.E.; Lowenstern, Jacob B.; Mortensen, A.K.; Pope, E.C.; Bird, D.K.; Reed, M.H.; Friðleifsson, G.O.; Elders, W.A.

    2013-01-01

    The Iceland Deep Drilling Project Well 1 was designed as a 4- to 5-km-deep exploration well with the goal of intercepting supercritical hydrothermal fluids in the Krafla geothermal field, Iceland. The well unexpectedly drilled into a high-silica (76.5 % SiO2) rhyolite melt at approximately 2.1 km. Some of the melt vesiculated while extruding into the drill hole, but most of the recovered cuttings are quenched sparsely phyric, vesicle-poor glass. The phenocryst assemblage is comprised of titanomagnetite, plagioclase, augite, and pigeonite. Compositional zoning in plagioclase and exsolution lamellae in augite and pigeonite record changing crystallization conditions as the melt migrated to its present depth of emplacement. The in situ temperature of the melt is estimated to be between 850 and 920 °C based on two-pyroxene geothermometry and modeling of the crystallization sequence. Volatile content of the glass indicated partial degassing at an in situ pressure that is above hydrostatic (~16 MPa) and below lithostatic (~55 MPa). The major element and minor element composition of the melt are consistent with an origin by partial melting of hydrothermally altered basaltic crust at depth, similar to rhyolite erupted within the Krafla Caldera. Chondrite-normalized REE concentrations show strong light REE enrichment and relative flat patterns with negative Eu anomaly. Strontium isotope values (0.70328) are consistent with mantle-derived melt, but oxygen and hydrogen isotope values are depleted (3.1 and −118 ‰, respectively) relative to mantle values. The hydrogen isotope values overlap those of hydrothermal epidote from rocks altered by the meteoric-water-recharged Krafla geothermal system. The rhyolite melt was emplaced into and has reacted with a felsic intrusive suite that has nearly identical composition. The felsite is composed of quartz, alkali feldspar, plagioclase, titanomagnetite, and augite. Emplacement of the rhyolite magma has resulted in partial melting of

  20. Geothermal Energy Databook for the Western United States (Draft Copy)

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, S.L.; Tavana, M.; Leung, K.; Schwartz, S.R.

    1979-06-01

    available data for geothermal sites is widely scattered, uneven in quantity and quality, and ranges from extensive for The Geysers and East Mesa areas to sparse for Alvord and Lassen. This is especially true for sites outside of California. The best available sources have been used to gather the data and every attempt has been made to assure that figures and facts quoted are the most accurate and up-to-date. Data are compiled from the original sources as much as possible, and new or revised data is added after its receipt. A table of page 14 lists leasing data as of late 1978 for the most important KGRs. Additionally, page 29 provides a list of the more important sites and characteristics. A table containing leasing data as of late 1978 begins on page 53. This report is part of the collection of much detailed historical data (history). There are many references at the end of this report. Additionally, this report is accompanied by appendices that included many maps and references. [Abstracters note: This was part of a large but short-lived effort at LBNL to collect lots of geothermal data. There may be other reports that are worth searching for to add to the Geothermal Legacy collection at OSTI. DJE-2005

  1. Reservoir stratum characterstics and geothermal resources potential of Rongcheng uplift geothermal field in Baoding, Hebei%河北保定容城凸起地热田储层属性与资源潜力

    Institute of Scientific and Technical Information of China (English)

    郭世炎; 李小军

    2013-01-01

    21世纪人类将面临资源、环境与灾害的严重挑战.地热资源作为绿色新型能源,可减少传统燃料的消耗,实现CO2减排,日益受到人们的青睐.河北保定市容城凸起地热田为我国东部代表性中低温地热田,其热储类型为基岩岩溶裂隙热储(主要为蓟县系雾迷山组及长城系高于庄组),具有储量大,可回灌等特点.根据现有数据和地质资料进行的地热资源潜力评估表明:容城凸起(56 km2研究区范围)基岩(3000 m以浅)热储地热资源量为416×1016J,相当于标准煤239×106t,折合热能1320 MW;可采地热资源量为62×1016 J,相当于标准煤36×106 t,折合热能198 MW.%The severe challenges for mankind in the 21st century are resource,environment,and disaster.Geothermal resource,as a green new energy,which could reduce the consumption of traditional fuels and implement the emission reduction of CO2,are becoming increasingly popular.Rongcheng Uplift geothermal field in Baoding,Hebei province is a typical low-medium temperature geothermal field in eastern China,and its geothermal reservoir is bedrock karstfissure of Middle Proterozoic Wumishan group Jxw and Gaoyuzhuang group Chg,and characterized by large water reserves and rechargeable reservior.Evaluation of the geothermal resource potential based on the existing data and geological information indicates:the geothermal reservoir of Rongcheng uplift (56 km2 in the study area) bedrock (shallower than 3000 m)has a total of 416×1016 J geothermal resource,equivalent to 239×106 t standard coal,which can convert to 1320 MW of heat.The estimated exploitable geothermal resource is 62×1016 J,equivalent to 36×106 t standard coal,or 198 MW heat.

  2. Environmental assessment of proposed geothermal well testing in the Tigre Lagoon Oil Field, Vermilion Parish, Louisiana

    Energy Technology Data Exchange (ETDEWEB)

    1976-03-01

    An environmental assessment is made of the proposed testing of two geopressured, geothermal aquifers in central coastal Louisiana. On the basis of an analysis of the environmental setting, subsurface characteristics, and the proposed action, potential environmental impacts are determined and evaluated together with potential conflicts with federal, state, and local programs. (LBS )

  3. Hydro-geochemical and isotopic fluid evolution of the Los Azufres caldera geothermal field, Central Mexico

    Science.gov (United States)

    González-Partida, E.; Viggiano-Guerra, J. C.; Pérez, R. J.

    2008-10-01

    Hydrothermal alteration at Los Azufres geothermal held is mostly propylitic showing progressive dehydration with depth, and temperature increase. The evolution of this system is inferred to be related to deep liquid water, boiling when ascending through fractures connected to the surface.

  4. Cerro Prieto Geothermal Field, Proceedings of the Symposium, 1st, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Barbier, E. (ed.)

    1979-01-01

    This conference is published in two volumes and contains 35 papers, 31 of which are abstracted separately. The subject matter is primarily concerned with the understanding of geology, hydrogeology, geophysics, reservoir engineering, geochemistry and electric power generation associated with the procurement of geothermal energy.

  5. The geothermal field below the city of Berlin, Germany: Results from structurally and parametrically improved 3D Models

    Science.gov (United States)

    Frick, Maximilian; Sippel, Judith; Cacace, Mauro; Scheck-Wenderoth, Magdalena

    2016-04-01

    The goal of this study was to quantify the influence of the geological structure and geophysical parametrization of model units on the geothermal field as calculated by 3D numerical simulations of coupled fluid and heat transport for the subsurface of Berlin, Germany. The study area is located in the Northeast German Basin which is filled with several kilometers of sediments. This sedimentary infill includes the clastic sedimentary units Middle Buntsandstein and Sedimentary Rotliegend which are of particular interest for geothermal exploration. Previous studies conducted in the Northeast German Basin have already shown the geometries and properties of the geological units majorly control the distribution of subsurface temperatures. In this study we followed a two-step approach, where we first improved an existing structural model by integrating newly available 57 geological cross-sections, well data and deep seismics (down to ~4 km). Secondly, we performed a sensitivity analysis investigating the effects of varying physical fluid and rock properties on the subsurface temperature field. The results of this study show, that the structural configuration of model units exerts the highest influence on the geothermal field (up to ± 23 K at 1000 m below sea level). Here, the Rupelian clay aquitard, displaying a heterogeneous thickness distribution, locally characterized by hydrogeological windows (i.e. domains of no thickness) enabling intra-aquifer groundwater circulation has been identified as major controlling factor. The new structural configuration of this unit (more continuous, less numerous hydrogeological windows) also leads to a reduction of the influence of different boundary conditions and heat transport mechanisms considered. Additionally, the models results show that calculated temperatures highly depend on geophysical properties of model units whereas the hydraulic conductivity of the Cenozoic succession was identified as most dominant, leading to changes

  6. Chemical composition of deep hydrothermal fluids in the Ribeira Grande geothermal field (São Miguel, Azores)

    Science.gov (United States)

    Carvalho, M. R.; Forjaz, V. H.; Almeida, C.

    2006-08-01

    The Ribeira Grande geothermal field is a water-dominated geothermal system, located within Água de Pau/Fogo Volcano in the central part of the São Miguel Island. This geothermal system is exploited for energy production by wells sustaining two power plants. The wells produce from a formation of pillow lavas divided into different aquifers, with a fairly isothermal zone from 800 to 1300 m in depth, where reservoir temperature reaches 230 to 245 °C. Below the depth of 1300 m there is a slight temperature reversal. The fluid produced has excess enthalpy and, separated at atmospheric pressure, is characterized by mineralization of sodium-chloride type up to 6-7 g/l, the concentration of dissolved silica varies between 450 and 650 mg/l and the pH ranges between 8 and 8.6. The gas phase is dominantly CO 2, at a concentration of 98% of NCG. The composition of the deep geothermal fluid was obtained by computer simulation, using the WATCH program, and was compared with the composition of the bottom-hole samples. The approximations, in this simulation, were considered the single- and multi-step steam separation. The reference temperatures were based on: (i) the measured temperature in wells; (ii) the Na/K geothermometric temperature and (iii) the enthalpy-saturation temperature. According to both the measured and geothermometric temperatures, the deep fluid of the wells has two phases with a steam fraction up to 0.34, at higher well discharges. The measured enthalpy is always greater than the calculated enthalpy. The calcite equilibrium indicates scaling, since the fluid is flashing, around 2.28 mg/l CaCO 3 at the maximum discharge. The geothermal wells exploit three different aquifers, the lower of which is liquid and slightly colder than the upper ones. The intermediate is a two-phase aquifer with a steam fraction up to 0.081. The upper aquifer is probably of steam phase. The main differences between the aquifers are the temperature and boiling; both enthalpy and

  7. Geothermal direct-heat utilization assistance

    Science.gov (United States)

    The report summarizes activities of the Geo-Heat Center (GHC) at Oregon Institute of Technology for the first quarter of Fiscal Year 1995. It describes contacts with parties during this period related to assistance with geothermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, resources and equipment. Research is also being conducted on geothermal energy cost evaluation, low-temperature geothermal resource assessment, use of silica waste from the Cerro Prieto geothermal field as construction materials and geothermal heat pumps. Outreach activities include the publication of a quarterly bulletin on direct heat applications and dissemination of information on low-temperature geothermal resources and utilization.

  8. Pumpernickel Valley Geothermal Project Thermal Gradient Wells

    Energy Technology Data Exchange (ETDEWEB)

    Z. Adam Szybinski

    2006-01-01

    The Pumpernickel Valley geothermal project area is located near the eastern edge of the Sonoma Range and is positioned within the structurally complex Winnemucca fold and thrust belt of north-central Nevada. A series of approximately north-northeast-striking faults related to the Basin and Range tectonics are superimposed on the earlier structures within the project area, and are responsible for the final overall geometry and distribution of the pre-existing structural features on the property. Two of these faults, the Pumpernickel Valley fault and Edna Mountain fault, are range-bounding and display numerous characteristics typical of strike-slip fault systems. These characteristics, when combined with geophysical data from Shore (2005), indicate the presence of a pull-apart basin, formed within the releasing bend of the Pumpernickel Valley – Edna Mountain fault system. A substantial body of evidence exists, in the form of available geothermal, geological and geophysical information, to suggest that the property and the pull-apart basin host a structurally controlled, extensive geothermal field. The most evident manifestations of the geothermal activity in the valley are two areas with hot springs, seepages, and wet ground/vegetation anomalies near the Pumpernickel Valley fault, which indicate that the fault focuses the fluid up-flow. There has not been any geothermal production from the Pumpernickel Valley area, but it was the focus of a limited exploration effort by Magma Power Company. In 1974, the company drilled one exploration/temperature gradient borehole east of the Pumpernickel Valley fault and recorded a thermal gradient of 160oC/km. The 1982 temperature data from five unrelated mineral exploration holes to the north of the Magma well indicated geothermal gradients in a range from 66 to 249oC/km for wells west of the fault, and ~283oC/km in a well next to the fault. In 2005, Nevada Geothermal Power Company drilled four geothermal gradient wells, PVTG-1

  9. Thermal History of the Felsite Unit, Geysers Geothermal Field, From Thermal Modeling of 40Ar/39Ar Incremental Heating Data

    Energy Technology Data Exchange (ETDEWEB)

    T. M. Harrison (U of California); G. B. Dalrymple (Oregon State U); J. B. Hulen (U of Utah); M. A. Lanphere; M. Grove; O. M. Lovera

    1999-08-19

    An Ar-40/Ar-39 and U-Pb study was performed of the Geysers plutonic complex of the Geysers Geothermal Field in California. Sixty-nine ion microprobe spot analyses of zircons from four granite samples from the plutonic complex that underlies the Geysers geothermal field yielded Pb-207/Pb-206 vs. U-238/Pb-206 concordia ages ranging from 1.13 {+-} 0.04 Ma to 1.25 {+-} 0.04 Ma. The U-Pb ages coincide closely with Ar-40/Ar-39 age spectrum plateau and ''terminal'' ages from coexisting K-feldspars and with the eruption ages of overlying volcanic rocks. The data indicate that the granite crystallized at 1.18 Ma and had cooled below 350 C by {approximately}0.9-1.0 Ma. Interpretation of the feldspar Ar-40/Ar-39 age data using multi-diffusion domain theory indicates that post-emplacement rapid cooling was succeeded either by slower cooling from 350-300 C between 1.0 and 0.4 Ma or transitory reheating to 300-350 C at about 0.4-0.6 Ma. Heat flow calculations constrained with K-feldspar thermal histories and the pre sent elevated regional heal flow anomaly demonstrate that appreciable heat input from sources external to the known Geysers plutonic complex is required to maintain the geothermal system. This requirement is satisfied by either a large, underlying, convecting magma chamber (now solidified) emplaced at 1.2 Ma or episodic intrusion of smaller bodies from 1.2-0.6 Ma.

  10. The Significance of Acid Alteration in the Los Humeros High-Temperature Geothermal Field, Puebla, Mexico.

    Science.gov (United States)

    Elders, W. A.; Izquierdo, G.

    2014-12-01

    The Los Humeros geothermal field is a high-enthalpy hydrothermal system with more than 40 drilled deep wells, mostly producing high steam fractions at > 300oC. However, although it has a large resource potential, low permeability and corrosive acid fluids have hampered development so that it currently has an installed electrical generating capacity of only 40 MWe. The widespread production of low pH fluids from the reservoir is inconsistent with the marked absence in the reservoir rocks of hydrothermal minerals typical of acid alteration. Instead the hydrothermal alteration observed is typical of that due to neutral to alkaline pH waters reacting with the volcanic rocks of the production zones. Thus it appears that since the reservoir has recently suffered a marked drop in fluid pressure and is in process of transitioning from being water-dominated to being vapor-dominated. However sparse examples of acid leaching are observed locally at depths of about 2 km in the form of bleached, intensely silicified zones, in low permeability and very hot (>350oC) parts of reservoir. Although these leached rocks retain their primary volcanic and pyroclastic textures, they are altered almost entirely to microcrystalline quartz, with some relict pseudomorphs of plagioclase phenocrysts and traces of earlier-formed hydrothermal chlorite and pyrite. These acid-altered zones are usually only some tens of meters thick and deeper rocks lack such silicification. The acid fluids responsible for their formation could either be magmatic volatiles, or could be formed during production (e.g. reaction of water and salts forming hydrogen chloride by hydrolysis at high temperatures). The very high boron content of the fluids produced by the Los Humeros wells suggests that their ultimate source is most likely magmatic gases. However, these acid gases did not react widely with the rocks. We suggest that the silicified zones are forming locally where colder descending waters are encountering

  11. Gas chemistry and thermometry of the Cerro Prieto, Mexico, geothermal field

    Science.gov (United States)

    Nehring, N.L.; D'Amore, F.

    1984-01-01

    Gas compositions of Cerro Prieto wells in 1977 reflected strong boiling in the reservoir around wells M-20 and M-25. This boiling zone appeared to be collapsing in 1982 when a number of wells in this area of the field were shut-in. In 1977 and 1982, gas compositions also showed boiling zones corresponding to faults H and L postulated by Halfman et al. (1982). Four gas geothermometers were applied, based on reservoir equilibria and calculated fugacities. The Fisher - Tropsch reaction predicted high temperatures and appeared to re-equilibrate slowly, whereas the H2S reaction predicted low temperatures and appeared to re-equilibrate rapidly. Hydrogen and NH3 reactions were intermediate. Like gas compositions, the geothermometers reflected reservoir processes, such as boiling. Surface gas compositions are related to well compositions, but contain large concentrations of N2 originating from air dissolved in groundwater. The groundwater appears to originate in the east and flow over the production field before mixing with reservoir gases near the surface. ?? 1984.

  12. Advanced Geothermal Turbodrill

    Energy Technology Data Exchange (ETDEWEB)

    W. C. Maurer

    2000-05-01

    Approximately 50% of the cost of a new geothermal power plant is in the wells that must be drilled. Compared to the majority of oil and gas wells, geothermal wells are more difficult and costly to drill for several reasons. First, most U.S. geothermal resources consist of hot, hard crystalline rock formations which drill much slower than the relatively soft sedimentary formations associated with most oil and gas production. Second, high downhole temperatures can greatly shorten equipment life or preclude the use of some technologies altogether. Third, producing viable levels of electricity from geothermal fields requires the use of large diameter bores and a high degree of fluid communication, both of which increase drilling and completion costs. Optimizing fluid communication often requires creation of a directional well to intersect the best and largest number of fracture capable of producing hot geothermal fluids. Moineau motor stators made with elastomers cannot operate at geothermal temperatures, so they are limited to the upper portion of the hole. To overcome these limitations, Maurer Engineering Inc. (MEI) has developed a turbodrill that does not use elastomers and therefore can operate at geothermal temperatures. This new turbodrill uses a special gear assembly to reduce the output speed, thus allowing a larger range of bit types, especially tri-cone roller bits, which are the bits of choice for drilling hard crystalline formations. The Advanced Geothermal Turbodrill (AGT) represents a significant improvement for drilling geothermal wells and has the potential to significantly reduce drilling costs while increasing production, thereby making geothermal energy less expensive and better able to compete with fossil fuels. The final field test of the AGT will prepare the tool for successful commercialization.

  13. Advanced Geothermal Turbodrill

    Energy Technology Data Exchange (ETDEWEB)

    W. C. Maurer

    2000-05-01

    Approximately 50% of the cost of a new geothermal power plant is in the wells that must be drilled. Compared to the majority of oil and gas wells, geothermal wells are more difficult and costly to drill for several reasons. First, most U.S. geothermal resources consist of hot, hard crystalline rock formations which drill much slower than the relatively soft sedimentary formations associated with most oil and gas production. Second, high downhole temperatures can greatly shorten equipment life or preclude the use of some technologies altogether. Third, producing viable levels of electricity from geothermal fields requires the use of large diameter bores and a high degree of fluid communication, both of which increase drilling and completion costs. Optimizing fluid communication often requires creation of a directional well to intersect the best and largest number of fracture capable of producing hot geothermal fluids. Moineau motor stators made with elastomers cannot operate at geothermal temperatures, so they are limited to the upper portion of the hole. To overcome these limitations, Maurer Engineering Inc. (MEI) has developed a turbodrill that does not use elastomers and therefore can operate at geothermal temperatures. This new turbodrill uses a special gear assembly to reduce the output speed, thus allowing a larger range of bit types, especially tri-cone roller bits, which are the bits of choice for drilling hard crystalline formations. The Advanced Geothermal Turbodrill (AGT) represents a significant improvement for drilling geothermal wells and has the potential to significantly reduce drilling costs while increasing production, thereby making geothermal energy less expensive and better able to compete with fossil fuels. The final field test of the AGT will prepare the tool for successful commercialization.

  14. GEOTHERMICS GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20091762 Guo Wancheng(Xining Jiulong Engineering Investigation Ltd.,Xining 810700,China);Shi Xingmei Development and Utilization of Guide Basin’s Geothermal Resources of Qinghai Province(Hydrogeology and Engineering Geology,ISSN1000-3665,CN11-2202/P,35(3),2008,p.79-80,92,2 illus.,2 tables,2 refs.)Key words:geothermal resources,QinghaiThis paper introduced the background of geothermal conditions and the many years of geothermal exploration data in Guide Basin.Then,the authors discussed the geothermal resources feature of Guide basin and raised some opinions on the reasonable development and utilization of geothermal resources.

  15. Three-Dimensional Velocity Structure of The Geysers Geothermal Field, CA, USA

    Science.gov (United States)

    Gritto, R.; Yoo, S.

    2012-12-01

    The aim of our project is to understand the relationship between geothermal operations and medium size earthquakes (M>3) at The Geysers Geothermal Reservoir, CA, USA. To reach that goal we have devised an approach combining 4-D seismic characterization of the reservoir structure, full moment tensor analysis of the source rupture processes, geomechanical modeling of the reservoir stresses and temperatures and seismic hazard analyses. In our presentation, we will present results based on seismic data collected by the Lawrence Berkeley National Laboratory with a 34-station seismic network from 2003 through present. Specifically, we will present 3-D P- and S-wave velocity structure of the reservoir for each year of data availability and investigate temporal changes between different epochs. The spatial pattern of temporal velocity changes is subsequently correlated to the available injection and production data to investigate the cause for the observed velocity changes.

  16. Neo-tectonic fracturing after emplacement of quaternary granitic pluton in the Kakkonda geothermal field, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Doi, N.; Kato, O. [JMC Goethermal Eng. Co., Ltd., Iwate-ken (Japan); Kanisawa, S.; Ishikawa, K. [Tohoku Univ., Sendai (Japan)

    1995-12-31

    The fracture which occurs in the Kakkonda geothermal system was formed by neo-tectonic stress after the emplacement of the neo-granite (Quaternary Kakkonda Granite) at middle Pleistocene to recent. The characteristic contrast in permeability at ca.1.5 km is strongly controlled by the contact metamorphic zone, especially cordierite and higher grade metamorphic zones, in which the high temperature (320{degrees}C<) and low permeable deep reservoir was created. The five geothermal wells 2.5-3.0 km deep have clarified that a microearthquake zone below -1.0 km shows high permeability especially at the margin of the Kakkonda Granite, and low permeability outside of a microearthquake zone. The Kakkonda Granite is a composite pluton which has very few fractures inside of it. Thus, neo-tectonic fracturing has developed in the non-metamorphosed Tertiary formations and the margin of the Kakkonda Granite.

  17. Bouillante geothermal field: mixing and water/rock interaction processes at 250°C.

    OpenAIRE

    Sanjuan, Bernard,; Brach, Michel; Lasne, Eric

    2001-01-01

    International audience; In the geothermal Bouillante area, electricity is presently produced from well BO-2 only. Following a successful stimulation operation in 1998, a second well BO-4 will be soon connected to the power plant. This paper presents relevant geochemical data obtained for both wells during 1998 and 2000. For some dissolved species, results show discrepancies between surface and down hole samples. In this case, additional information from thermal springs can be very useful to r...

  18. Monitoring and modeling land subsidence at the Cerro Prieto Geothermal Field, Baja California, Mexico, using SAR interferometry

    Science.gov (United States)

    Carnec, Claudie; Fabriol, Hubert

    Images derived from repeat-pass spaceborne interferometric synthetic aperture radar (InSAR) systems offer the possibility of mapping surface deformation of small spatial extent and monitoring its spatio-temporal evolution. A slow local subsidence has been detected at the Cerro Prieto geothermal field from images acquired by the European Space Agency remote sensing satellites ERS-1/2 between 1993 and 1997. Although agricultural activity in the area limited the investigation, interferometric monitoring revealed that the ground deformation is associated with the withdrawal of geothermal fluid and agreed with the leveling data. Modeling of the subsidence was carried out assuming elastic deformation in a half-space from simple point sources, of which five were necessary to reproduce the fringe patterns observed on the interferograms. The depths and locations of three of the sources are compatible with the location of the known reservoir. The study improves prior knowledge of the displacement field and of the mecanisms involved in the subsidence phenomenon.

  19. Inversion of Synthetic Aperture Radar Interferograms for Sources of Production-Related Subsidence at the Dixie Valley Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Foxall, W; Vasco, D

    2003-02-07

    We used synthetic aperture radar interferograms to image ground subsidence that occurred over the Dixie Valley geothermal field during different time intervals between 1992 and 1997. Linear elastic inversion of the subsidence that occurred between April, 1996 and March, 1997 revealed that the dominant sources of deformation during this time period were large changes in fluid volumes at shallow depths within the valley fill above the reservoir. The distributions of subsidence and subsurface volume change support a model in which reduction in pressure and volume of hot water discharging into the valley fill from localized upflow along the Stillwater range frontal fault is caused by drawdown within the upflow zone resulting from geothermal production. Our results also suggest that an additional source of fluid volume reduction in the shallow valley fill might be similar drawdown within piedmont fault zones. Shallow groundwater flow in the vicinity of the field appears to be controlled on the NW by a mapped fault and to the SW by a lineament of as yet unknown origin.

  20. Environmental protection at the Los Azufres, Michoacan geothermal field; La proteccion ambiental en el campo geotermico de Los Azufres, Michoacan

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza Rangel, Ernesto; Hernandez Ayala, Cuauhtemoc [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)

    2004-12-01

    Geothermal-electric development is a sustainable activity from an environmental viewpoint, as is proved by the operation and management of the Los Azufres geothermal field. Impacts to soil and vegetation can be prevented and adequately mitigated. Liquid residues can be returned to the reservoir avoiding contaminating surface and ground waters and aquifers; and atmospheric emissions can kept bellow allowable limits. The main environmental technical experiences of Comision Federal de Electricidad (CFE) in this field are presented in this paper. [Spanish] El desarrollo geotermoelectrico es una actividad sustentable desde el punto de vista ambiental, como lo prueba el manejo del campo geotermico de Los Azufres. Los impactos al suelo y a la vegetacion pueden prevenirse y mitigarse con las medidas adecuadas. Los desechos liquidos pueden regresarse al yacimiento sin contaminar cuerpos de agua superficiales o acuiferos someros, y las emisiones a la atmosfera pueden controlarse para mantenerlas dentro de limites permisibles. Se presentan las principales experiencias tecnicas de tipo ambiental obtenidas por la Comision Federal de Electricidad (CFE) en ese campo.

  1. Relation of compositions of deep fluids in geothermal activity of Pleistocene-Holocene volcanic fields of Lesser Caucasus

    Science.gov (United States)

    Meliksetian, Khachatur; Lavrushin, Vassily; Shahinyan, Hrach; Aidarkozhina, Altin; Navasardyan, Gevorg; Ermakov, Alexander; Zakaryan, Shushan; Prasolov, Edward; Manucharyan, Davit; Gyulnazaryan, Shushan; Grigoryan, Edmond

    2017-04-01

    It is widely accepted, that geothermal activity in the conductive heat flow processes, such as volcanism and hydrothermal activity, is manifestation of the thermal mass transfer process in the Earth's crust, where geothermal and geochemical processes are closely connected. Therefore, geochemistry and isotope compositions of thermal mineral waters within and on periphery of volcanic clusters may represent key indicators for better understanding of geothermal activity in geodynamically active zones. Geochemical features of heat and mass transport in hydrothermal systems related to active volcanic and fault systems in continental collision related orogenic elevated plateaus such as Anatolian-Armenian-Iranian highlands are still poorly understood. In this contribution we attempt to fill these gaps in our knowledge of relations of geochemical and geothermal processes in collision zones. We present new data on chemical compositions, trace element geochemistry of thermal waters of Lesser Caucasus, (Armenia) as well as isotope analysis of free gases such as {}3He/{}4He, {}40Ar/{}36Ar, δ{}13?(CO{}2), nitrogen δ{}15N(N{}2) and oxygen and hydrogen isotopes in water phases (δD, δ{}18O). To reveal some specific features of formation of fluid systems related to thermal activity in the areas of collision related active volcanism and active geodynamics a complex geochemical (SiO{}2, K-Na, Na-Li, Li-Mg) and isotope geothermometers (δ{}18O(CaCO{}3) - δ{}18O(H{}2O)) were applied. The distribution of δ{}13?(??{}2) values in free gases of mineral waters of Armenia demonstrates that gases related to Quaternary volcanic fields are characterized by relatively light δ{}13?(CO{}2) values close to mantle derived gases, while on periphery of volcanic systems relatively heavy values of δ{}13?(CO{}2) indicate strong influence of metamorphic and sedimentary derived carbon dioxide. Distribution of nitrogen isotopes δ{}15N(N{}2) demonstrate an inverse correlation with δ{}13?(CO{}2

  2. Geothermal Energy

    Energy Technology Data Exchange (ETDEWEB)

    Steele, B.C.; Harman, G.; Pitsenbarger, J. [eds.

    1996-02-01

    Geothermal Energy Technology (GET) announces on a bimonthly basis the current worldwide information available on the technologies required for economic recovery of geothermal energy and its use as direct heat or for electric power production.

  3. Geothermal energy

    OpenAIRE

    Manzella A.

    2015-01-01

    Geothermal technologies use renewable energy resources to generate electricity and direct use of heat while producing very low levels of greenhouse-gas (GHG) emissions. Geothermal energy is stored in rocks and in fluids circulating in the underground. Electricity generation usually requires geothermal resources temperatures of over 100°C. For heating, geothermal resources spanning a wider range of temperatures can be used in applications such as space and district heating (and cooling, with p...

  4. Idaho Geothermal Commercialization Program. Idaho geothermal handbook

    Energy Technology Data Exchange (ETDEWEB)

    Hammer, G.D.; Esposito, L.; Montgomery, M.

    1980-03-01

    The following topics are covered: geothermal resources in Idaho, market assessment, community needs assessment, geothermal leasing procedures for private lands, Idaho state geothermal leasing procedures - state lands, federal geothermal leasing procedures - federal lands, environmental and regulatory processes, local government regulations, geothermal exploration, geothermal drilling, government funding, private funding, state and federal government assistance programs, and geothermal legislation. (MHR)

  5. Differentiating induced and natural seismicity using space-time-magnitude statistics applied to the Coso Geothermal field

    Science.gov (United States)

    Schoenball, Martin; Davatzes, Nicholas C.; Glen, Jonathan M. G.

    2015-01-01

    A remarkable characteristic of earthquakes is their clustering in time and space, displaying their self-similarity. It remains to be tested if natural and induced earthquakes share the same behavior. We study natural and induced earthquakes comparatively in the same tectonic setting at the Coso Geothermal Field. Covering the preproduction and coproduction periods from 1981 to 2013, we analyze interevent times, spatial dimension, and frequency-size distributions for natural and induced earthquakes. Individually, these distributions are statistically indistinguishable. Determining the distribution of nearest neighbor distances in a combined space-time-magnitude metric, lets us identify clear differences between both kinds of seismicity. Compared to natural earthquakes, induced earthquakes feature a larger population of background seismicity and nearest neighbors at large magnitude rescaled times and small magnitude rescaled distances. Local stress perturbations induced by field operations appear to be strong enough to drive local faults through several seismic cycles and reactivate them after time periods on the order of a year.

  6. Geothermal Energy.

    Science.gov (United States)

    Bufe, Charles Glenn

    1983-01-01

    Major activities, programs, and conferences in geothermal energy during 1982 are highlighted. These include first comprehensive national assessment of U.S. low-temperature geothermal resources (conducted by U.S. Geological Survey and Department of Energy), map production by U.S. Geological Survey, geothermal plant production, and others. (JN)

  7. The geochemistry and isotope hydrology of the Southern Mexicali Valley in the area of the Cerro Prieto, Baja California (Mexico) geothermal field

    Science.gov (United States)

    Portugal, Enrique; Izquierdo, Georgina; Truesdell, Alfred; Álvarez, Julio

    2005-11-01

    Groundwaters from the phreatic aquifer within and surrounding of the Cerro Prieto geothermal field were analyzed geochemically and isotopically in order to establish a hydrodynamic model of the study zone, which is located in the Mexicali Valley between 655,000-685,000 m E-W and 3,605,000-3,576,000 m N-S relative to UTM coordinates. Based on their chemical composition three types of water were recognized: chloride, sulfate and bicarbonate. However four groups of water were identified on a statistical multi-variable method of cluster analysis (A-D). The average temperature is 25 °C; with a few exceptions in the south where temperature can be as high as 47 °C. Stable isotope ratios for some waters plot close to the world meteoric line, corresponding to the original unaltered waters of the zone. The hydrogeochemistry varies in relation to three principal processes: evaporation, infiltration of water used in agriculture and rock interaction by reaction with evaporitic deposits. Major quartz, calcite and plagioclase and minor smectite, kaolinite, halite, sylvite and gypsum were identified by X-ray diffraction in lacustrine sediments of the central part of the zone. Chemical modeling indicates saturation with respect to calcite and undersaturation with respect to gypsum. By incorporating chemical and isotope data into geological and isopotential well information, a hydrodynamic model has been postulated. In this hydrodynamic model the water (A) enters the study zone from the east and it is originally of the old Colorado River water. The water samples on which the model is based were draw from agricultural wells that intersected two aquifers, a shallow and a deep one, representing the recharge to the zone. The salinity of the deep aquifer water (B) is lower than that of the shallow aquifer water (C) and so is the stable isotope ratio. The difference is though to be due to dissolution of evaporates, evaporation and possible infiltration of spent agriculture water. Both

  8. Direct utilization of geothermal resources field experiments at Monroe, Utah. Final report, July 14, 1978-July 13, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Blair, C.K.; Owen, L.B. (eds.)

    1982-12-01

    The City of Monroe, Utah undertook a project to demonstrate the economic and technical viability of utilizing a low temperature geothermal resource to provide space and hot water heating to commercial, municipal, and domestic users within the community. During the course of the project, resource development and assessment, including drilling of a production well, was successfully completed. Upon completion of the field development and assessment phase of the program and of a preliminary design of the district heating system, it was determined that the project as proposed was not economically viable. This was due to: (1) a significant increase in estimated capital equipment costs resulting from the general inflation in construction costs, the large area/low population density in Monroe, and a more remote fluid disposal well site than planned, could not balance increased construction costs, (2) a lower temperature resource than predicted, and (3) due to predicted higher pumping and operating costs. After a thorough investigation of alternatives for utilizing the resource, further project activities were cancelled because the project was no longer economical and an alternative application for the resource could not be found within the constraints of the project. The City of Monroe, Utah is still seeking a beneficial use for the 600 gpm, 164/sup 0/F geothermal well. A summary of project activities included.

  9. Time-series analysis of surface deformation at Brady Hot Springs geothermal field (Nevada) using interferometric synthetic aperture radar

    Energy Technology Data Exchange (ETDEWEB)

    Ali, S. T. [Univ. of Wisconsin, Madison, WI (United States); Akerley, J. [Ormat Technologies Inc., Reno, NV (United States); Baluyut, E. C. [Univ. of Wisconsin, Madison, WI (United States); Cardiff, M. [Univ. of Wisconsin, Madison, WI (United States); Davatzes, N. C. [Temple Univ., Philadelphia, PA (United States). Dept. of Earth and Environmental Science; Feigl, K. L. [Univ. of Wisconsin, Madison, WI (United States); Foxall, W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fratta, D. [Univ. of Wisconsin, Madison, WI (United States); Mellors, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Spielman, P. [Ormat Technologies Inc., Reno, NV (United States); Wang, H. F. [Univ. of Wisconsin, Madison, WI (United States); Zemach, E. [Ormat Technologies Inc., Reno, NV (United States)

    2016-05-01

    We analyze interferometric synthetic aperture radar (InSAR) data acquired between 2004 and 2014, by the ERS-2, Envisat, ALOS and TerraSAR-X/TanDEM-X satellite missions to measure and characterize time-dependent deformation at the Brady Hot Springs geothermal field in western Nevada due to extraction of fluids. The long axis of the ~4 km by ~1.5 km elliptical subsiding area coincides with the strike of the dominant normal fault system at Brady. Within this bowl of subsidence, the interference pattern shows several smaller features with length scales of the order of ~1 km. This signature occurs consistently in all of the well-correlated interferometric pairs spanning several months. Results from inverse modeling suggest that the deformation is a result of volumetric contraction in shallow units, no deeper than 600 m, likely associated with damaged regions where fault segments mechanically interact. Such damaged zones are expected to extend downward along steeply dipping fault planes, providing a high permeability conduit to the production wells. Using time series analysis, we test the hypothesis that geothermal production drives the observed deformation. We find a good correlation between the observed deformation rate and the rate of production in the shallow wells. We also explore mechanisms that could potentially cause the observed deformation, including thermal contraction of rock, decline in pore pressure and dissolution of minerals over time.

  10. Spatial distribution of temperature in the low-temperature geothermal Euganean field (NE Italy): a simulated annealing approach

    Energy Technology Data Exchange (ETDEWEB)

    Fabbri, Paolo; Trevisani, Sebastiano [Dipartimento di Geologia, Paleontologia e Geofisica, Universita degli Studi di Padova, via Giotto 1, 35127 Padova (Italy)

    2005-10-01

    The spatial distribution of groundwater temperatures in the low-temperature (60-86{sup o}C) geothermal Euganean field of northeastern Italy has been studied using a geostatistical approach. The data set consists of 186 temperatures measured in a fractured limestone reservoir, over an area of 8km{sup 2}. Investigation of the spatial continuity by means of variographic analysis revealed the presence of anisotropies that are apparently related to the particular geologic structure of the area. After inference of variogram models, a simulated annealing procedure was used to perform conditional simulations of temperature in the domain being studied. These simulations honor the data values and reproduce the spatial continuity inferred from the data. Post-processing of the simulations permits an assessment of temperature uncertainties. Maps of estimated temperatures, interquartile range, and of the probability of exceeding a prescribed 80{sup o}C threshold were also computed. The methodology described could prove useful when siting new wells in a geothermal area. (author)

  11. Seismic tremor and gravity measurements at Inferno Crater Lake, Waimangu Geothermal Field, New Zealand

    Science.gov (United States)

    O'Brien, J. F.; Jolly, A. D.; Fournier, N.; Cole-Baker, J.; Hurst, T.; Roman, D. C.

    2011-12-01

    Volcanic crater lakes are often associated with active hydrothermal systems that induce cyclic behavior in the lake's level, temperature, and chemistry. Inferno Crater Lake, located in the Waimangu geothermal field within the Taupo Volcanic Zone (TVZ) on the North Island of New Zealand exhibits lake level fluctuations of >7m, and temperature fluctuations >40°C with a highly variable periodicity. Seismic and gravity monitoring of Inferno Lake was carried out from December, 2009 - March, 2010 and captured a full cycle of lake fluctuation. Results indicate that this cycle consisted of ~5 smaller fluctuations of ~3m in lake level followed by a larger fluctuation of ~7m. A broadband seismometer recorded strong seismic tremor in the hours leading up to each of the minor and major high stands in lake level. Spectral analysis of the tremor shows dominant frequencies in the range of ~10Hz and a fundamental harmonic frequency located in the 1Hz range. The 1Hz frequency band exhibits gliding spectral lines which increase in frequency at the end of each tremor period. Particle motion analysis of harmonic tremor waveforms indicate a ~100m upward migration of the source location from the onset of tremor until it ceases at the peak of each lake level high stand. Particle motions also indicate an azimuthal migration of the source by ~30° from the overflow outlet region of the lake toward the central vent location during the course of the tremor and lake level increase. Lake water temperature has a direct relationship with lake level and ranges between ~40°C - ~80°C. Gravity fluctuations were also continuously monitored using a Micro-g-LaCoste gPhone relative gravity meter with a 1Hz sampling rate and precision of 1 microgal. These data indicate a direct relationship between lake level and gravity showing a net increase of ~100 microgals between lake level low and high stands. A piezometer located beside the lake indicates an inflow of ground water into the subsoil during

  12. Authigenic layer silicate minerals in borehole Elmore 1, Salton Sea Geothermal Field, California, USA

    Science.gov (United States)

    McDowell, S. Douglas; Elders, Wilfred A.

    1980-10-01

    A combined petrographic/X-ray/electron microprobe and energy dispersive system investigation of sandstone cuttings from borehole Elmore # 1 near the center of the Salton Sea Geothermal Field has revealed numerous regular variations in the composition, texture, mineralogy and proportions of the authigenic layer silicate minerals in the temperature interval 185° C (411.5 m depth) to 361° C (2,169 m). At temperatures near 190° C, dolomite/ankerite+calcite-bearing sandstones contain an illite/mixed layer phase with 10% expandable layers (dolomite/ankerite zone). In shale, the percentage of expandable layers in the mixed layer phase changes from 10 15% at 185° C to 5% at 210° C (494 m). In the interval 250° C (620 m) to 325° C (1,135 m), the calcite+pyrite+epidote-bearing sandstones contain a layer silicate assemblage of chlorite and illite (chlorite-calcite zone). In the shallower portions of this metamorphic zone, the illite contains 0 5% expandable layers, while at depths greater than 725 m (275° C) it is completely free of expandable layers. On increasing temperature, the white mica shows regular decreases in SiIV, Mg and Fe, and increase in AlIV, AlVI, and interlayer occupancy, as it changes gradually from fine-grained illite (=textural sericite) to coarse-grained recrystallized phengitic white mica. In the same interval, chlorite shows decreases in AlVI and octahedral vacancies and an increase in total Mg+Fe. The sandstones range from relatively unmodified detrital-textured rocks with porosities up to 20% and high contents of illite near 250° C to relatively dense hornfelsic-textured rocks with trace amounts of chlorite and phengite and porosities near 5% at 325° C. Numerous complex reactions among detrital (allogenic) biotite, chlorite, and muscovite, and authigenic illite and chlorite, occur in the chlorite-calcite zone. Biotite appears, and calcite disappears, at a temperature near 325° C and a depth of 1,135m. The biotite zone so produced persists

  13. Investigation of Low-Temperature Geothermal Resources in the Sonoma Valley Area, California

    Energy Technology Data Exchange (ETDEWEB)

    Youngs, Leslie G.; Chapman, Rodger H.; Chase, Gordon W.; Bezore, Stephen P.; Majmundar, Hasu H.

    1983-01-01

    The Sonoma Valley area contains low-temperature geothermal resources (20 C {le} T {le} 90 C) having the potential for useful development. Sonoma Valley residents, local governments and institutions, private developers, and manufacturers may be able to utilize the geothermal resources as an alternate energy source. Historically, there have been at least six geothermal spring areas developed in the Sonoma Valley. Four of these (Boyes Hot Springs, Fetter's Hot Springs, Agua Caliente Springs, and the Sonoma State Hospital warm spring) lie on a linear trend extending northwestward from the City of Sonoma. Detailed geophysical surveys delineated a major fault trace along the east side of the Sonoma Valley in association with the historic geothermal areas. Other fault traces were also delineated revealing a general northwest-trending structural faulting fabric underlying the valley. Water wells located near the ''east side'' fault have relatively high boron concentrations. Geochemical evidence may suggest the ''east side'' fault presents a barrier to lateral fluid migration but is a conduit for ascending fluids. Fifteen of the twenty-nine geothermal wells or springs located from literature research or field surveys are located along or east of this major fault in a 10 km (6.2 miles) long, narrow zone. The highest recorded water temperature in the valley appears to be 62.7 C (145 F) at 137.2 meters (450 feet) in a well at Boyes Hot Springs. This is consistent with the geothermal reservoir temperature range of 52-77 C (126-171 F) indicated by geothermometry calculations performed on data from wells in the area. Interpretation of data indicates a low-temperature geothermal fluid upwelling or ''plume'', along the ''east side'' fault with subsequent migration into permeable aquifers predominantly within volcanic strata. It is quite likely other geothermal fluid &apos

  14. Is mudflow in Sidoarjo, East Java due to the pumping mechanism of hot air bubbles? : Laboratory simulations and field observations

    Science.gov (United States)

    Nurhandoko, Bagus Endar B.

    2015-09-01

    Extraordinary mudflow has happened in Sidoarjo, East Java, Indonesia since 2006. This mud comes from the giant crater that is located close to the BJP - 01. Thousands of homes have been submerged due to mudflow. Till today this giant mud crater is still has great strength despite the mud flowing over 8 years. This is a very rare phenomenon in the world. This mud flow mechanism raises big questions, because it has been going on for years, naturally the mudflow will stop by itself because the pressure should be reduced. This research evaluates all aspects of integrated observations, laboratory tests and field observations since the beginning of this ongoing mudflow. Laboratory tests were done by providing hot air bubbles into the fluid inside the inverted funnel showed that the fluid can flow with a high altitude. It is due to the mechanism of buoyant force from air bubbles to the water where the contrast density of the water and the air is quite large. Quantity of air bubbles provides direct effect to the debit of fluid flow. Direct observation in the field, in 2006 and 2007, with TIMNAS and LPPM ITB showed the large number of air bubbles on the surface of the mud craters. Temperature observation on the surface of mud crater is around 98 degree C whereas at greater depth shows the temperature is increasingly rising. This strengthens the hypothesis or proves that the mud pumping mechanism comes from buoyant force of hot air bubbles. Inversion gravity images show that the deep subsurface of main crater is close to volcanic layers or root of Arjuna mountain. Based on the simulation laboratory and field observation data, it can be concluded that the geothermal factor plays a key role in the mudflow mechanism.

  15. Mexican-American Cooperative Program at the Cerro Prieto geothermal field: Analysis of the Nuevo Leon magnetic anomaly and its possible relation to the Cerro Prieto magmatic-hydrothermal system

    Science.gov (United States)

    Goldstein, N. E.; Wilt, M. J.; Corrigan, D. J.

    1982-10-01

    The broad dipolar magnetic anomaly whose positive peak is centered near Ejido Nuevo Leon, some 5 km east of the Cerro Prieto I Power Plant, has long been suspended to have a genetic relationship to the thermal source of the Cerro Prieto geothermal system. This suspicion was reinforced after several deep geothermal wells, drilled to depths of 3 to 3.5 km over the anomaly, intersected an apparent dike-sill complex consisting mainly of diabase but with minor rhyodacite. A detailed fit of the observed magnetic field to a computer model indicates that the source may be approximated by a tabular block 4 by 6 km in area, 3.7 km in depth, 2.3 km thick, and dipping slightly to the north. Mafic dike chips from one well, NL-1, were analyzed by means of electron microprobe analyses which showed them to contain a titanomagnetite that is paramagnetic at in-situ temperature conditions. As the dike mineralogy does not account for the magnetic anomaly, the magnetic source is believed to be a deeper, magnetite-rich assemblage of periodotite-gabbro plutons.

  16. Relationship of geological and geothermal field properties: Midcontinent area, USA, an example

    Science.gov (United States)

    Forster, A.; Merriam, D.F.; Brower, J.C.

    1993-01-01

    Quantitative approaches to data analysis in the last decade have become important in basin modeling and mineral-resource estimation. The interrelation of geological, geophysical, geochemical, and geohydrological variables is important in adjusting a model to a real-world situation. Revealing the interdependences of variables can contribute in understanding the processes interacting in sedimentary basins. It is reasonably simple to compare spatial data of the same type but more difficult if different properties are involved. Statistical techniques, such as cluster analysis or principal components analysis, or some algebraic approaches can be used to ascertain the relations of standardized spatial data. In this example, structural configuration on five different stratigraphic horizons, one total sediment thickness map, and four maps of geothermal data were copared. As expected, the structural maps are highly related because all had undergone about the same deformation with differing degrees of intensity. The temperature gradients derived (1) from shallow borehole logging measurements under equilibrium conditions with the surrounding rock, and (2) from non-equilibrium bottom-hole temperatures (BHT) from deeper depths are mainly independent of each other. This was expected and confirmed also for the two temperature maps at 1000 ft which were constructed using both types of gradient values. Thus, it is evident that the use of a 2-point (BHT and surface temperature) straightline calculation of a mean temperature gradient gives different information about the geothermal regime than using gradients from temperatures logged under equilibrium conditions. Nevertheless, it is useful to determine to what a degree the larger dataset of nonequilibrium temperatures could reflect quantitative relationships to geologic conditions. Comparing all maps of geothermal information vs. the structural and the sediment thickness maps, it was determined that all correlations are moderately

  17. Numerical modeling of high-temperature deep wells in the Cerro Prieto geothermal field, Mexico

    OpenAIRE

    García, A.; F. Ascencio; Espinosa, G.; E. Santoyo; H. Gutiérrez; V. Arellano

    1999-01-01

    A numerical modeling study of three non-producing deep geothermal wells from Cerro Prieto is presented. We compute the expected production characteristics of these wells in order to determine if their inability to sustain flow was due to (i) heat loss effects in the well, (ii) the influence of production casing diameters, (iii) the transient heat loss during the first few days of well discharge, or (iv) the effect of secondary low-enthalpy inflows. A new version of the wellbore flow simulator...

  18. Overview of the Mexican-American cooperative program at the Cerro Prieto geothermal field

    Science.gov (United States)

    Lippmann, M. J.; Zelwer, R.

    1982-09-01

    The Lawrence Berkeley Laboratory is coordinating the US technical activities being carried out at Cerro Prieto under a five-year agreement between the US Department of Energy and the Comission Federal de Electricidad de Mexico. This agreement, signed in July 1977, is expected to expire in July 1982. Efforts are being made to continue some of the research beyond the formal termination of the agreement. A description of the program, which involves studies of geology, geophysics, hydrodynamics, subsidence, geothermal wells and reservoirs, and aquifers, is discussed.

  19. Land subsidence in the Cerro Prieto Geothermal Field, 1 Baja California, Mexico, from 1994 to 2005. An integrated analysis of DInSAR, levelingand geological data.

    Energy Technology Data Exchange (ETDEWEB)

    Sarychikhina, O; Glowacka, E; Mellors, R; Vidal, F S

    2011-03-03

    Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994- 1997 and 1997-2006) and detailed geological information in order to improve the understanding of temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the spatial pattern of the subsidence as well as changes in rate are highly correlated with the development of the Cerro Prieto Geothermal Field.

  20. Land subsidence in the Cerro Prieto Geothermal Field, Baja California, Mexico, from 1994 to 2005: An integrated analysis of DInSAR, leveling and geological data

    Science.gov (United States)

    Sarychikhina, Olga; Glowacka, Ewa; Mellors, Robert; Vidal, Francisco Suárez

    2011-07-01

    Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to the local infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994-1997 and 1997-2006) and detailed geological information in order to improve understanding of the temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the changes in spatial pattern and rate of the subsidence are correlated with the development of the Cerro Prieto Geothermal Field.

  1. Seasonal Variation of the East Asian Subtropical Westerly Jet and Its Association with the Heating Field over East Asia

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The structure and seasonal variation of the East Asian Subtropical Westerly Jet (EAWJ) and associations with heating fields over East Asia are examined by using NCEP/NCAR reanalysis data.Obvious differences exist in the westerly jet intensity and location in different regions and seasons due to the ocean-land distribution and seasonal thermal contrast, as well as the dynamic and thermodynamic impacts of the Tibetan Plateau. In winter, the EAWJ center is situated over the western Pacific Ocean and the intensity is reduced gradually from east to west over the East Asian region. In summer, the EAWJ center is located over the north of the Tibetan Plateau and the jet intensity is reduced evidently compared with that in winter. The EAWJ seasonal evolution is characterized by the obvious longitudinal inconsistency of the northward migration and in-phase southward retreat of the EAWJ axis. A good correspondence between the seasonal variations of EAWJ and the meridional differences of air temperature (MDT) in the mid-upper troposphere demonstrates that the MDT is the basic reason for the seasonal variation of EAWJ. Correlation analyses indicate that the Kuroshio Current region to the south of Japan and the Tibetan Plateau are the key areas for the variations of the EAWJ intensities in winter and in summer,respectively. The strong sensible and latent heating in the Kuroshio Current region is closely related to the intensification of EAWJ in winter. In summer, strong sensible heating in the Tibetan Plateau corresponds to the EAWJ strengthening and southward shift, while the weak sensible heating in the Tibetan Plateau is consistent with the EAWJ weakening and northward migration.

  2. Geology of the Pavana geothermal area, Departamento de Choluteca, Honduras, Central America: Field report

    Energy Technology Data Exchange (ETDEWEB)

    Eppler, D.B.; Heiken, G.; Wohletz, K.; Flores, W.; Paredes, J.R.; Duffield, W.A.

    1987-09-01

    The Pavana geothermal area is located in southern Honduras near the Gulf of Fonseca. This region is underlain by late Tertiary volcanic rocks. Within ranges near the geothermal manifestations, the rock sequences is characterized by intermediate to mafic laharic breccias and lavas overlain by silicic tuffs and lavas, which are in turn overlain by intermediate to mafic breccias, lavas, and tuffs. The nearest Quaternary volcanoes are about 40 km to the southwest, where the chain of active Central American volcanoes crosses the mouth of the Gulf of Fonseca. Structure of the Pavana area is dominated by generally northwest-trending, southwest-dipping normal faults. This structure is topographically expressed as northwest-trending escarpments that bound blocks of bedrock separated by asymmetric valleys that contain thin alluvial deposits. Thermal waters apparently issue from normal faults and are interpreted as having been heated during deep circulation along fault zones within a regional environment of elevated heat flow. Natural outflow from the main thermal area is about 3000 l/min of 60/sup 0/C water. Geothermometry of the thermal waters suggests a reservoir base temperature of about 150/sup 0/C.

  3. Evaluation of the solute geothermometry of thermal springs and drilled wells of La Primavera (Cerritos Colorados) geothermal field, Mexico: A geochemometrics approach

    Science.gov (United States)

    Pandarinath, Kailasa; Domínguez-Domínguez, Humberto

    2015-10-01

    A detailed study on the solute geothermometry of thermal water (18 springs and 8 drilled wells) of La Primavera geothermal field (LPGF) in Mexico has been carried out by employing a geochemical database compiled from the literature and by applying all the available solute geothermometers. The performance of these geothermometers in predicting the reservoir temperatures has been evaluated by applying a geochemometrics (geochemical and statistical) method. The springs of the LPGF are of bicarbonate type and the majority have attained partial-equilibrium chemical conditions and the remaining have shown non-equilibrium conditions. In the case of geothermal wells, water is dominantly of chloride-type and, among the studied eight geothermal wells, four have shown full-equilibrium chemical conditions and another four have indicated partial-equilibrium conditions. All springs of HCO3-​ type water have provided unreliable reservoir temperatures, whereas the only one available spring of SO42- type water has provided the reservoir temperature nearer to the average BHT of the wells. Contrary to the general expected behavior, spring water of non-equilibrium and geothermal well water of partial-equilibrium chemical conditions have indicated more reliable reservoir temperatures than those of partially-equilibrated and fully-equilibrated water, respectively. Among the chemical concentration data, Li and SiO2 of two springs, SO42- and Mg of four springs, and HCO3 and Na concentrations of two geothermal wells were identified as outliers and this has been reflected in very low reservoir temperatures predicted by the geothermometers associated with them (Li-Mg, Na-Li, Na-K-Mg, SiO2 etc.). Identification of the outlier data points may be useful in differentiating the chemical characteristics, lithology and the physico-chemical and geological processes at the sample locations of the study area. In general, the solute geothermometry of the spring waters of LPGF indicated a dominantly

  4. Depth migration of seasonally induced seismicity at The Geysers geothermal field

    Science.gov (United States)

    Johnson, Christopher W.; Totten, Eoghan J.; Bürgmann, Roland

    2016-06-01

    Seismicity from injected fluids provides insight into the hydraulically conductive fracture network at The Geysers (TG), California, geothermal reservoir. Induced earthquakes at TG result from both thermoelastic and poroelastic stresses as injected fluids cool the rocks and increase pore pressure. The spatiotemporal evolution of M ≥ 1.5 seismicity is characterized as a function of depth in the northwest and southeast regions of TG to develop time-dependent earthquake rates using an epidemic-type aftershock sequence model. The seismicity and injection follow an annual cycle that peaks in the winter months and is correlated by depth. The results indicate a time lag of ≤6 months for fluids to migrate >3 km below the injection depth. Water injection is the main cause of seismicity as fluids penetrate into the reservoir. Our results suggest that a steeply dipping fracture network of hydraulically conductive faults allows fluid migration to a few kilometers below the point of injection.

  5. Dynamics of a geothermal field traced by noble gases: Cerro Prieto, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Mazor, E. (Weizmann Inst. of Science, Rehovot, Israel); Truesdell, A.H.

    1981-01-01

    Noble gases have been measured mass spectrometrically in samples collected during 1977 from producing wells at Cerro Prieto. Positive correlations between concentrations of radiogenic (He, /sup 40/Ar) and atmospheric noble gases (Ne, Ar, and Kr) suggest the following dynamic model: the geothermal fluids originated from meteoric water penetrated to more than 2500 m depth (below the level of first boiling) and mixed with radiogenic helium and argon-40 formed in the aquifer rocks. Subsequently, small amounts of steam were lost by a Raleigh process (0 to 3%) and mixing with shallow cold water occurred (0 to 30%). Noble gases are sensitive tracers of boiling in the initial stages of 0 to 3% steam separation and complement other tracers, such as Cl or temperature, which are effective only beyond this range.

  6. Dynamics of a geothermal field traced by noble gases: Cerro Prieto, Mexico

    Science.gov (United States)

    Mazor, E.; Truesdell, A.H.

    1984-01-01

    Noble gases have been measured mass spectrometrically in samples collected during 1977 from producing wells at Cerro Prieto. Positive correlations between concentrations of radiogenic (He and 40Ar) and atmospheric noble gases (Ne, Ar and Kr) suggest the following dynamic model: the geothermal fluids originated from meteoric water that penetrated to more than 2500 m depth (below the level of first boiling) and mixed with radiogenic He and 40Ar formed in the aquifer rocks. Subsequently, small amounts of steam were lost by a Raleigh process (0 - 30%) and mixing with shallow cold water occurred (0 - 30%). Noble gases are sensitive tracers of boiling in the initial stages of 0 - 3% steam separation and complement other tracers, such as C1 or temperature, which are effective only beyond this range. ?? 1984.

  7. The Tianjin geothermal field (north-eastern China): Water chemistry and possible reservoir permeability reduction phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Minissale, Angelo; Montegrossi, Giordano; Orlando, Andrea [Institute of Geosciences and Earth Resources, National Research Council of Italy (CNR), Via G. La Pira 4, 50121 Florence (Italy); Borrini, Daniele; Tassi, Franco [Department of Earth Sciences, University of Florence, Via G. La Pira 4, 50121 Florence (Italy); Vaselli, Orlando [Institute of Geosciences and Earth Resources, National Research Council of Italy (CNR), Via G. La Pira 4, 50121 Florence (Italy); Department of Earth Sciences, University of Florence, Via G. La Pira 4, 50121 Florence (Italy); Huertas, Antonio Delgado [Estacion Experimental de Zaidin (CSIC), Prof. Albareda 1, 18008 Granada (Spain); Yang, Jincheng; Cheng, Wanquing [Aode Renewable Energy Research Institute, 90 Weijin South Road, Nankai District, 300381 Tianjin (China); Tedesco, Dario [Department of Environmental Sciences, Second University of Naples, Via Vivaldi 43, Caserta 81100 (Italy); Institute of Environmental Geology and Geo Engineering (CNR), Piazzale A. Moro 5, Roma 00100 (Italy); Poreda, Robert [Department of Earth and Environmental Sciences, University of Rochester, 227 Hutchison Hall, Rochester, NY 14627 (United States)

    2008-08-15

    Injection of spent (cooled) thermal fluids began in the Tianjin geothermal district, north-eastern China, at the end of the 1990s. Well injectivities declined after 3-4 years because of self-sealing processes that reduced reservoir permeability. The study focuses on the factors that may have caused the observed decrease in permeability, using chemical and isotopic data on fluids (water and gas) and mineral phases collected from production and injection wells. The results of data processing and interpretation indicate that (1) it is very unlikely that calcite and silica precipitation is taking place in the reservoir; (2) the Fe- and Zn-rich mineral phases (e.g. sulfides, hydroxides and silicates) show positive saturation indexes; (3) SEM and XRD analyses of filtered material reveal that the latter mineral phases are common; (4) visual observation of casings and surface installations, and of corrosion products, suggests that a poor quality steel was used in their manufacture; (5) significant quantities of solids (e.g. quartz and feldspar crystals) are carried by the geothermal fluid; (6) seasonal changes in fluid composition lead to a reduction in casing corrosion during the summer. It was concluded that the decrease in injectivity in the Tianjin wells is caused only in part by the oxidation of casings, downhole pumps, and surface installations, triggered by free oxygen in the injected fluids; the utilization of better quality steels should drastically reduce this type of corrosion. Self-sealing of pores and fractures by reservoir formation solids and by the Fe-corrosion products suspended in the injected fluids seems to be a more important phenomenon, whose effect could be greatly reduced by installing filtering devices at all sites. (author)

  8. Time-dependent Induced Seismicity Rates Described with an Epidemic Type Aftershock Sequence Model at The Geysers Geothermal Field, California

    Science.gov (United States)

    Johnson, C. W.; Totten, E. J.; Burgmann, R.

    2015-12-01

    To improve understanding of the link between injection/production activity and seismicity, we apply an Epidemic Type Aftershock Sequence (ETAS) model to an earthquake catalog from The Geysers geothermal field (GGF) between 2005-2015 using >140,000 events and Mc 0.8 . We partition the catalog along a northeast-southwest trending divide, which corresponds to regions of high and low levels of enhanced geothermal stimulation (EGS) across the field. The ETAS model is fit to the seismicity data using a 6-month sliding window with a 1-month time step to determine the background seismicity rate. We generate monthly time series of the time-dependent background seismicity rate in 1-km depth intervals from 0-5km. The average wellhead depth is 2-3 km and the background seismicity rates above this depth do not correlate well with field-wide injected masses over the time period of interest. The auto correlation results show a 12-month period for monthly time series proximal to the average wellhead depths (2-3km and 3-4km) for northwest GGF strongly correlates with field-wide fluid injection masses, with a four-month phase shift between the two depth intervals as fluid migrates deeper. This periodicity is not observed for the deeper depth interval of 4-5 km, where monthly background seismicity rates reduce to near zero. Cross-correlation analysis using the monthly time series for background seismicity rate and the field-wide injection, production and net injection (injection minus production) suggest that injection most directly modulates seismicity. Periodicity in the background seismicity is not observed as strongly in the time series for the southeast field. We suggest that the variation in background seismicity rate is a proxy for pore-pressure diffusion of injected fluids at depth. We deduce that the contrast between the background seismicity rates in the northwest and southeast GGF is a result of reduced EGS activity in the southeast region.

  9. Primary Study on Geological Characteristics of Nuanquan Geothermal Field in Liaoning Xiuyan%辽宁岫岩暖泉地热田地质特征浅析

    Institute of Scientific and Technical Information of China (English)

    刘志超; 王伟; 孙成宇

    2014-01-01

    断裂构造是控制辽宁省岫岩县暖泉地热田地热异常的主导构造,地热系统属于“断控对流型”地热系统,属低温地热区,热储呈带状。地热异常区中心位于F1、F2断裂交汇部位。地下热水是在构造裂隙中储存的原生地下热水,为裂隙热储。热储受构造和岩性共同控制,热储岩性为印支期二长花岗岩,上覆盖层为砂及砂砾卵石,地热水可命名为氟、偏硅酸复合型医疗矿水。%The dominant structure that lead to the abnormal geothermal phenomenon of Nuanquan geothermal field in Liaoning Xiuyan is fracture.The geothermal system belongs to “break controlling convection”,“hypothermia”and“ribbon”type.The geothermal anomaly area center located in the intersection of F1 and F2.Underground hot water is stored in the native structural fracture, belongs to fracture geothermal reservoir.Thermal reservoir is controlled by structure and lithology,Thermal reservoir lithology is indo-chinese epoch monzonitic granite that covered with sand and gravel.Geothermal water can be named as complex medical mineral water contained fluorine, metasilicic acid.

  10. Subsurface geology of Los Humeros geothermal field, Puebla, Mexico; Geologia del subsuelo del campo geotermico de Los Humeros, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Cedillo Rodriguez, Fidel [Comision federal de Electricidad, Perote, Veracruz, Mexico(Mexico)

    2000-12-01

    In the 1980s, most geologists correlated subsurface geology at Los Humeros geothermal field using penetrated by faults, as interpreted by photogeology. These were structural objectives for geothermal drilling programs. Recent petrology reinterpretation of data from well cutting lets us identify nine lithologic units, with the Toba Vitrea Humeros as the index horizon. The study of the subsurface geology allows us to demonstrate- based on the distribution, depth, and thickness of the lithologic units- that the augite andesites, the Toba Vitrea Humeros, the hornblende andesites, the basalt, and the metamorphosed limestone are affected by system of hidden faults (with no surface evidence) replaced by major fracture zones able to contain steam. Thus these hidden faults are the structural objectives controlling design and sitting of new wells. We conclude that the lithologic unit of augite andesites forms the upper geothermal reservoir, and the hornblende andesites and basalt comprise the lower reservoir- separated from each other by the Toba Vitrea Humeros lithologic unit. Based on the subsurface geologic model, we propose drilling 40 new wells, a long and parallel the north-south faults system. [Spanish] En la decada de los 80s se agrupo la geologia del subsuelo de Los Humeros en cuatro unidades litologicas afectadas por fallas interpretadas por fotogeologia. Estas fallas eran el objetivo estructural para programar la perforacion de pozos geotermicos. La reinterpretacion de los datos de petrologia de las muestras de canal permite identificar nueve unidades litologicas, de las cuales la unidad Toba Vietrea Humeros se comporta como horizonte indice. El estudio de la geologia del subsuelo permite demostrar, con base en la distribucion, profundidades y espesores de las unidades litologicas, que las andesitas de augita, la Toba Vitrea Humeros, las andesitas de hornblenda, los basaltos, y las calizasmetamorfizadas estan afectadas por sistemas de fallas ocultas (sin

  11. Seismic activity and stress tensor inversion at Las Tres Vírgenes Volcanic and Geothermal Field (México)

    Science.gov (United States)

    Antayhua-Vera, Yanet; Lermo-Samaniego, Javier; Quintanar-Robles, Luis; Campos-Enríquez, Oscar

    2015-10-01

    We analyze local earthquakes occurring between 2003 and 2012 at the Las Tres Vírgenes Volcanic and Geothermal Field (TVVGF) to establish their temporal and spatial distribution, and relationships with local and regional fault systems, water injection, acid stimulation and steam production tests. We obtained focal mechanisms and inverted data for the stress tensor to understand the local and regional stress fields. We analyzed 423 local earthquakes with magnitudes between 0.1 and 2.9 Mc and hypocentral depths from 0.2 to 7.4 km b.s.l. The cutoff depth at ~ 7.4 km possibly delineates the brittle-ductile transition zone. We identified seven swarms (from 1 to 7). Swarms 1 (December 2009), 2 (May 2010), 3 (June-July 2010) and 7 (December 2012) are strongly correlated with injection processes; whereas swarms 5 (April 2012) and 6 (September 2012) are correlated with local tectonic faults. Stress inversion showed NW-SE, E-W and NE-SW extensional orientations (Shmin), in agreement with the local tectonic stress field; while NE-SW compressional orientations (SHmax) are correlated with the regional tectonic stress field.

  12. Geothermal systems: Principles and case histories

    Science.gov (United States)

    Rybach, L.; Muffler, L. J. P.

    The classification of geothermal systems is considered along with the geophysical and geochemical signatures of geothermal systems, aspects of conductive heat transfer and regional heat flow, and geothermal anomalies and their plate tectonic framework. An investigation of convective heat and mass transfer in hydrothermal systems is conducted, taking into account the mathematical modelling of hydrothermal systems, aspects of idealized convective heat and mass transport, plausible models of geothermal reservoirs, and preproduction models of hydrothermal systems. Attention is given to the prospecting for geothermal resources, the application of water geochemistry to geothermal exploration and reservoir engineering, heat extraction from geothermal reservoirs, questions of geothermal resource assessment, and environmental aspects of geothermal energy development. A description is presented of a number of case histories, taking into account the low enthalpy geothermal resource of the Pannonian Basin in Hungary, the Krafla geothermal field in Northeast Iceland, the geothermal system of the Jemez Mountains in New Mexico, and extraction-reinjection at the Ahuachapan geothermal field in El Salvador.

  13. Investigation of geothermal resources in Korea (Geothermal Resources Maps)

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jeong Ung; Lee, Seung Gu; Yum, Byoung Woo; Kim, Hyoung Chan [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1996-12-01

    The Korean Peninsula forms a part of the stable foreland of Far East Asia and is a part of Sino-Korean Craton, where, hence, is not associated with high potential geothermal resources. Nevertheless, there are several geothermal springs, of which water temperature ranges from 23 to 76 deg. C. This study was aimed to draw various geothermal base maps in the Korean Peninsula, such as thermal conductivity map, heat flow map, geothermal gradient map, depth contour map of 25 deg. C and various geochemical figures of geothermal waters. In this study, the thermal springs was surveyed for well inventory, the determination of thermal conductivities of rocks, and chemical analyses of geothermal waters. Hydrogen and oxygen isotope values ({delta}D and {delta}{sup 18}O) of geothermal waters were also calculated, which would be useful to evaluate the origin of water. Map of geothermal gradient distribution illustrates geothermally anomalous areas - such as Deoksan, Dogo, Onyang and Yusong areas in ChungNam district, Jungwon area in Chungbuk district, Pocheon area in Gyeonggi district, Gosung area in Gwangwon district, Deokgu, Baekam, and Pohang areas in Gyeongbuk district and Busan, Mageumsan and Bugok area in Gyeongnam district. Heat flow map also shows similar features to geothermal anomalies. Most of thermal waters form the Korean Peninsula are alkaline and belongs to Na-HCO{sub 3} type. Their contents are characterized of low total dissolved solids and high contents of fluoride and sodium, of which results are same as those of the researches which was conducted before. (author). 21 refs., tabs., figs.

  14. GEOTHERMICS GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>20122531 Hu Lingzhi ( Institute of Geological Engineering Design & Research of Beijing,Miyun 101500,China );Wang Jiankang Discussion on the Feasibility of Geothermal Resources Development and Utilization in Miyun District,Beijing ( City Geology,ISSN1007-1903,CN11-5519 / P,6 ( 3 ), 2011,p.34-35,59 ,) Key words:geothermal resources,Beijing Geothermal,as a new type of clean energy with the integrated trinity of " heat energy-mineral resource-water resource ",

  15. Chemical and physical reservoir parameters at initial conditions in Berlin geothermal field, El Salvador: a first assessment

    Energy Technology Data Exchange (ETDEWEB)

    D`Amore, F. [CNR, Pisa (Italy). International Institute for Geothermal Research ; Mejia, J.T. [Comision Ejuctiva Hidroelectrica del Rio Lempa, El Salvador (El Salvador)

    1999-02-01

    A study has been made to obtain the main chemical and physical reservoir conditions of the Berlin field (El Salvador), before the commencement of large-scale exploitation of the geothermal resource. The upflow zone and the main flow path within the geothermal system have been determined from the area distribution of chemical parameters such as Cl concentrations, ratios such as Na/K, K/Mg, K/Ca, and temperatures computed from silica concentrations and cation ratios. Gas compositions have been used to calculate reservoir parameters such as temperature, steam fraction and P{sub CO{sub 2}}. The computer code WATCH (new edition 1994) has been used to evaluate the temperature of equilibrium between the aqueous species and selected alteration minerals in the reservoir. The fluid in Berlin flows to the exploited reservoir from the south, entering it in the vicinity of well TR-5. Along its flow-path (south-north direction), the fluid is cooled by boiling and conductive cooling. The chloride-enthalpy diagram indicates the existence of a parent water, with a chemical composition similar to well TR-5, that boils and the residual brine produces the fluid of well TR-3, which is very concentrated in salts. The fluid of TR-5 is probably produced from this parent water, generating the fluids of wells TR-2 and TR-9 by boiling, and the fluids of wells TR-1 and TR-4 by conductive cooling. The computed values for the deep steam fraction clearly indicate that this is a liquid-dominated system, with computed temperature values decreasing from 310{sup o}C (upflow zone) to about 230{sup o}C, from south to north. (author)

  16. Monitoring of Acoustic Emissions Within Geothermal Areas in Iceland: A new Tool for Geothermal Exploration.

    Science.gov (United States)

    Brandsdóttir, B.; Gudmundsson, O.

    2007-12-01

    With increased emphasis on geothermal development new exploration methods are needed in order to improve general understanding of geothermal reservoirs, characterize their extent and assess the potential for sustainable power production. Monitoring of acoustic emissions within geothermal areas may provide a new tool to evaluate the spatial extent of geothermal fields and model rock-fluid interactions. Three-dimensional seismic data have been used to assess the spatial and temporal distribution of noise within several high-temperature geothermal fields in Iceland. Seismic noise in the 4-6 Hz range within the Svartsengi field can be attributed to steam hydraulics and pressure oscillations within the geothermal reservoirs. Seismic noise surveys compliment electrical resistivity soundings and TEM-surveys by providing information pertinent to the current geothermal activity and extent of steam fields within the uppermost crust of the geothermal reservoir. Information related to acoustic emissions can thus help define targets for future wells.

  17. GEOTHERMICS GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20150342Guan Yu(Geo-Environment Monitoring Station of Anhui Province,Hefei230001,China);Chen Xun On Shallow Geothermal Energy Investigation in Urban Planning Zone of Bengbu in Anhui Province(Journal of Geology,ISSN1674-3636,CN32-1796/P,38(1),2014,p.88-93,2illus.,4tables,6refs.)Key words:geothermal energy,Anhui Province The authors conducted studies on shallow geothermal energy in urban planning zone in Bengbu of Anhui Province,depicted the geological settings of shallow geothermal energy,analyzed the natural features,heat exchange

  18. Geothermal Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Leffel, C.S., Jr.; Eisenberg, R.A.

    1977-06-01

    This handbook is intended to assist the physicist, chemist, engineer, and geologist engaged in discovering and developing geothermal energy resources. This first section contains a glossary of the approximately 500 most frequently occurring geological, physical, and engineering terms, chosen from the geothermal literature. Sections 2 through 8 are fact sheets that discuss such subjects as geothermal gradients, rock classification, and geological time scales. Section 9 contains conversion tables for the physical quantities of interest for energy research in general and for geothermal research in particular.

  19. Study and utilization of water-dominated and low-temperature geothermal fields in Italy; Itaria ni okeru nessui takuetsugata oyobi teion chinetsu shigen no kenkyu to riyo jokyo

    Energy Technology Data Exchange (ETDEWEB)

    Yasukawa, K. [Geological Survey of Japan, Tsukuba (Japan)

    1998-06-15

    This paper reports the state of research and development of hot-water dominated and low-temperature geothermal resources in Italy. Geothermal explorations and studies are conducted by the Italian electric power company ENEL and the International Geothermal Research Institute, of which the development of geothermal power generation is carried out by ENEL. Hot water dominated geothermal fields in the central Italy include the Tuscany area having Larderello south of Firenze and the Monte Amiata area, the Latium area around Rome, and the Campania area around Napoli. Low-temperature geothermal fields in the northern Italy include Ferrara, Vicenza, Euganei Hills, and Aqui Terme. A large number of wells have been drilled to as deep as 3000 m in high-temperature geothermal areas for power generation. The present drilling is targeted exclusively at deep reservoirs. In the hot water dominated areas in the central Italy, power plants of 20-MW class are built even in areas with not too high productivity, where waste hot water is utilized in binary cycle. In the northern low-temperature geothermal area, warm water is utilized directly. 8 refs., 14 figs.

  20. Design and analysis of a 5-MW vertical-fluted-tube condenser for geothermal applications

    Energy Technology Data Exchange (ETDEWEB)

    Llewellyn, G.H.

    1982-03-01

    The design and analysis of an industtial-sized vertical-fluted-tube condenser. The condenser is used to condense superheated isobutane vapor discharged from a power turbine in a geothermal test facility operated for the US Department of Energy. The 5-MW condenser has 1150 coolant tubes in a four-pass configuration with a total heat transfer area of 725 m/sup 2/ (7800 ft/sup 2/). The unit is being tested at the Geothermal Components Test Facility in the Imperial Valley of East Mesa, California. The condenser design is based on previous experimental research work done at the Oak Ridge National Laboratory on condensing refrigerants on a wide variety of single vertical tubes. Condensing film coefficients obtained on the high-performance vertical fluted tubes in condensing refrigerants are as much as seven times greater than those obtained with vertical smooth tubes that have the same diameter and length. The overall heat transfer performance expected from the fluted tube condenser is four to five times the heat transfer obtained from the identical units employing smooth tubes. Fluted tube condensers also have other direct applications in the Ocean Thermal Energy Conversion (OTEC) program in condensing ammonia, in the petroleum industry in condensing light hydrocarbons, and in the air conditioning and refrigeration industry in condensing fluorocarbon vapors.

  1. Genesis Model of the Tangquan Geothermal Field in Hebei Province%河北遵化汤泉地热田成因模式

    Institute of Scientific and Technical Information of China (English)

    李攻科; 王卫星; 杨峰田; 李宏; 沈键; 董路阳

    2015-01-01

    河北遵化汤泉地热资源丰富,阐明其成因模式对于该地热田的进一步开发和热水资源的可持续利用具有一定的指导意义。基于地温测量和水文地球化学分析等方法对其进行了系统研究,结果表明该地热田属中低温对流型地热系统。地热田在其以北的山区接受大气降水补给,补给高程下限约为935 m。地热流体在深循环过程中于正常的大地热流背景下被围岩逐渐加热,热储温度约为130℃,循环深度约为4800 m。在汤泉福泉宫至疗养院一带,构造切割花岗岩体,使得深部地热流体沿破碎带上涌,混合并加热赋存于蓄水构造中的片麻岩裂隙水,形成汤泉地区的地热异常。%Tangquan is located in the northwest of Zunhua city,Hebei Province.The region is of hilly land-scape ,and rich in geothermal resources.It is of great importance to elucidate the genesis mechanism of the geo-thermal field for sustainable development of the geothermal resources.In this paper,we conducted a systematic study to explore into the genesis mechanism through well temperature logging and hydrogeochemical investiga-tion.Results show that the geothermal field belongs to a low to medium temperature geothermal system of con-vective type.The geothermal fluid origins from the rainfall recharged in the mountainous area located to the north of geothermal field,with a recharge elevation of more than 935 m.The geothermal fluid is gradually heat-ed by the surrounding rock under a normal heat flow background during a deep cycling of ca.4,800 m,with a reservoir temperature of ca. 1 30 ℃.In the zone of Fuquan palace to sanatorium in Tangquan area where several faults cut through the monzonitic granite body,the geothermal fluid up flow along the faults and mix with the fis-sure water stored in the gneisses,forming the Tangquan geothermal field.

  2. Coupled flow and geomechanics modeling of fracture reactivation and induced seismicity in the Basel geothermal field

    Science.gov (United States)

    Tyukhova, A.; Castineira, D.; Juanes, R.

    2016-12-01

    Triggered and induced seismicity is at the cornerstone of discussions surrounding a wide range of subsurface technologies, e.g. unconventional hydrocarbon recovery, geologic carbon sequestration, underground gas storage, and geothermal energy extraction. We revisit the geothermal experiment in Basel, Switzerland, in which over 11 thousand cubic meters of water were injected into deep fractured crystalline rock. The injection took place in December 2006 and was performed at a single injection well, in three stages with increasing injection rate. Seismicity in the region increased during the experiment—with most of the seismic events occurring in the month following injection—and declined slowly after, but with seismic events still being recorded years after injection. The increase in seismicity is caused by reactivation of the pre-existing fractures: an increase in pore pressure decreases the normal effective stress across the fracture, which according to the Mohr-Coulomb failure criterion are therefore more prone to slip. The underlying processes, however, may be more complex. It is unclear the role that enhanced hydraulic connectivity in the fracture network plays on triggered seismicity, and on the emergence of seismicity clusters in space. It is also unclear what determines the delay between injection and recorded seismicity, and whether it can be explained by means of pressure propagation and/or dynamic weakening of fractures due to a drop in the friction coefficient as a result of decreased roughness from fracture slip. Here, we employ a computational model of coupled flow and geomechanics to quantitatively assess the impact of fluid injection on the recorded seismicity. We develop a simulation model that incorporates more than ten fractures, whose location, rake and dip are consistent with clusters of seismicity from a relocation of hypocenters and focal mechanisms. We adopt a multiscale description of flow (representing these fractures planes explicitly

  3. Methods for collection and analysis of geopressured geothermal and oil field waters

    Science.gov (United States)

    Lico, Michael S.; Kharaka, Yousif K.; Carothers, William W.; Wright, Victoria A.

    1982-01-01

    Present methods are described for the collection, preservation, and chemical analysis of waters produced from geopressured geothermal and petroleum wells. Detailed procedures for collection include precautions and equipment necessary to ensure that the sample is representative of the water produced. Procedures for sample preservation include filtration, acidification, dilution for silica, methyl isobutyl ketone (MIBK) extraction of aluminum, addition of potassium permanganate to preserve mercury, and precipitation of carbonate species as strontium carbonate for stable carbon isotopes and total dissolved carbonate analysis. Characteristics determined at the well site are sulfide, pH, ammonia, and conductivity. Laboratory procedures are given for the analysis of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, iron, manganese, zinc, lead, aluminum, .and mercury by atomic absorption and flame emission spectroscopy. Chloride is determined by silver nitrate titration and fluoride by ion-specific electrode. Bromide and iodide concentrations are determined by the hypochlorite oxidation method. Sulfate is analyzed by titration using barium chloride with thorin indicator after pretreatment with alumina. Boron and silica are determined colorimetrically by the carmine and molybdate-blue methods, respectively. Aliphatic acid anions (C2 through C5) are determined by gas chromatography after separation and concentration in a chloroform-butanol mixture.

  4. Water adsorption at high temperature on core samples from The Geysers geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Gruszkiewicz, M.S.; Horita, J.; Simonson, J.M.; Mesmer, R.E.

    1998-06-01

    The quantity of water retained by rock samples taken from three wells located in The Geysers geothermal reservoir, California, was measured at 150, 200, and 250 C as a function of pressure in the range 0.00 {le} p/p{sub 0} {le} 0.98, where p{sub 0} is the saturated water vapor pressure. Both adsorption (increasing pressure) and desorption (decreasing pressure) runs were made in order to investigate the nature and the extent of the hysteresis. Additionally, low temperature gas adsorption analyses were performed on the same rock samples. Nitrogen or krypton adsorption and desorption isotherms at 77 K were used to obtain BET specific surface areas, pore volumes and their distributions with respect to pore sizes. Mercury intrusion porosimetry was also used to obtain similar information extending to very large pores (macropores). A qualitative correlation was found between the surface properties obtained from nitrogen adsorption and the mineralogical and petrological characteristics of the solids. However, there is in general no proportionality between BET specific surface areas and the capacity of the rocks for water adsorption at high temperatures. The results indicate that multilayer adsorption rather than capillary condensation is the dominant water storage mechanism at high temperatures.

  5. San Ignacio (La Tembladera) geothermal site, Departamento de Francisco Morazan, Honduras, Central America: Geological field report

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, M.J.; Eppler, D.; Heiken, G.; Flores, W.; Ramos, N.; Ritchie, A.

    1987-06-01

    The San Ignacio (La Tembladera) geothermal site is located on the north side of the Siria Valley, Departamento de Francisco Morazan, near the village of Barrosa. Hot springs are located along a northwest-trending fault scarp at the edge of the valley and along north-trending faults that cross the scarp. The rocks in the area are primarily Paleozoic metamorphic rocks, overlain by patches of Tertiary Padre Miguel Group tuffs and alluvial deposits. Movement probably occurred along several faults during latest Tertiary and possibly early Quaternary times. Four spring areas were mapped. Area 1, the largest, is associated with a sinter mound and consists of 40 spring groups. About half of the springs, aligned along a north-south trend, are boiling. Area 2 is a small sinter mound with several seeps. Area 3 consists of a group of hot and boiling springs aligned along a north-trending fault. The springs rise through fractured schists and a thin cover of alluvium. Area 4 is located at the intersection of several faults and includes one of the largest boiling springs in the area.

  6. Potential of low-temperature geothermal resources in northern California. Report No. TR13

    Energy Technology Data Exchange (ETDEWEB)

    Hannah, J.L.

    1975-01-01

    Economically feasible uses for geothermal heat at temperatures too low for conventional electrical power generation at present are delineated. Several geothermal resource areas in northern California that have development potential are described, and applications of the heat found in each area are suggested. Plates are included of the following field study areas: the east side of the Sierra-Cascade Range north of Bishop, and the northern Coast Range from San Francisco Bay to Clear Lake. The counties included in the study area are Mo doc, Lassen, Sierra, Plumas, Placer, Alpine, Mono, Mendocino, Lake, and Sonoma. (LBS)

  7. An analysis of hydrochemical characteristics of Yiliang geothermal field%宜良地热田水化学特征分析与研究

    Institute of Scientific and Technical Information of China (English)

    张艳花; 徐世光; 巴俊杰; 李晨晨; 童文辉

    2016-01-01

    水化学特征不仅应用于分析地下水水质的时空变化规律,而且还提供地下水水动力环境信息。水化学分析方法已成为对探索地热田成因、地下水补给来源等常用的研究方法。基于近些年的研究资料,综合分析热储层结构特征和水化学特征,认为宜良地热田为层状热储型中低温地热田,其热储层为震旦系灯影组。研究热储层流体的化学分布特征以及热流体的化学成分与温度的关系等,用化学温标核算了热储层温度,认为 K-Mg 温标更适用于中低温地热田热储温度的估算。地热水水化学特征等基本地质特征可作为地热田规划和开发的理论基础。%Hydrochemical characteristic is a useful information which not only can be applied in the analysis of spatio-temporal variation rules of groundwater quality,but also indicates the groundwater hydrodynamic en-vironment.The hydrochemical analysis method has become a commonly used research technique of exploring genesis of geothermal field and source of groundwater recharge.Based on the research data in recent years, the authors conducted a integrated analysis on the structural characteristics and hydrochemical characteristics of thermal reservoir,and concluded that Yiliang geothermal field was a stratabound thermal reservoir type low-medium temperature geothermal field.The thermal reservoir is in Dengying Formation of Sinian sys-tem.Then the authors studied the chemical distribution characteristics of thermal reservoir fluids and the re-lationship between fluid chemical composition and temperature.By using chemical thermometric scale to ver-ify the temperature of the thermal reservoir,it appears that K-Mg thermometric scale is more suitable for the estimate of thermal reservoir temperature in low-medium temperature geothermal field.Basic geological characteristics including geochemical characteristics of geothermal water can be used as the theoretical basis of

  8. Configuration of the mudstones, gray- and coffee-colored shale lithologic units, zones of silica and epidote, and their relation to the tectonics of the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Cobo R, J.M.

    1981-01-01

    Based on well cuttings, five lithological units have been recognized within the area of what is now the Cerro Prieto geothermal field. These five units are described. Differences in origin, mineralogy, grading, color, compaction, etc., are shown.

  9. Geothermal Energy

    Energy Technology Data Exchange (ETDEWEB)

    Steele, B.C.; Pichiarella, L.S. [eds.; Kane, L.S.; Henline, D.M.

    1995-01-01

    Geothermal Energy (GET) announces on a bimonthly basis the current worldwide information available on the technologies required for economic recovery of geothermal energy and its use as direct heat or for electric power production. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database during the past two months.

  10. Geopressured geothermal bibliography (Geopressure Thesaurus)

    Energy Technology Data Exchange (ETDEWEB)

    Hill, T.R.; Sepehrnoori, K.

    1981-08-01

    This thesaurus of terminology associated with the geopressured geothermal energy field has been developed as a part of the Geopressured Geothermal Information System data base. A thesaurus is a compilation of terms displaying synonymous, hierarchical, and other relationships between terms. These terms, which are called descriptors, constitute the special language of the information retrieval system, the system vocabulary. The Thesaurus' role in the Geopressured Geothermal Information System is to provide a controlled vocabulary of sufficient specificity for subject indexing and retrieval of documents in the geopressured geothermal energy field. The thesauri most closely related to the Geopressure Thesaurus in coverage are the DOE Energy Information Data Base Subject Thesaurus and the Geothermal Thesaurus being developed at the Lawrence Berkeley Laboratory (LBL). The Geopressure Thesaurus differs from these thesauri in two respects: (1) specificity of the vocabulary or subject scope and (2) display format.

  11. Geopressured geothermal bibliography (Geopressure Thesaurus)

    Energy Technology Data Exchange (ETDEWEB)

    Hill, T.R.; Sepehrnoori, K.

    1981-08-01

    This thesaurus of terminology associated with the geopressured geothermal energy field has been developed as a part of the Geopressured Geothermal Information System data base. A thesaurus is a compilation of terms displaying synonymous, hierarchical, and other relationships between terms. These terms, which are called descriptors, constitute the special language of the information retrieval system, the system vocabulary. The Thesaurus' role in the Geopressured Geothermal Information System is to provide a controlled vocabulary of sufficient specificity for subject indexing and retrieval of documents in the geopressured geothermal energy field. The thesauri most closely related to the Geopressure Thesaurus in coverage are the DOE Energy Information Data Base Subject Thesaurus and the Geothermal Thesaurus being developed at the Lawrence Berkeley Laboratory (LBL). The Geopressure Thesaurus differs from these thesauri in two respects: (1) specificity of the vocabulary or subject scope and (2) display format.

  12. Numerical and experimental study of the mesa configuration in high-voltage 4H-SiC PiN rectifiers

    Science.gov (United States)

    Deng, Xiao-Chuan; Chen, Xi-Xi; Li, Cheng-Zhan; Shen, Hua-Jun; Zhang, Jin-Ping

    2016-08-01

    The effect of the mesa configuration on the reverse breakdown characteristic of a SiC PiN rectifier for high-voltage applications is analyzed in this study. Three geometrical parameters, i.e., mesa height, mesa angle and mesa bottom corner, are investigated by numerical simulation. The simulation results show that a deep mesa height, a small mesa angle and a smooth mesa bottom (without sub-trench) could contribute to a high breakdown voltage due to a smooth and uniform surface electric field distribution. Moreover, an optimized mesa structure without sub-trench (mesa height of 2.2 μm and mesa angle of 20°) is experimentally demonstrated. A maximum reverse blocking voltage of 4 kV and a forward voltage drop of 3.7 V at 100 A/cm2 are obtained from the fabricated diode with a 30-μm thick N- epi-layer, corresponding to 85% of the ideal parallel-plane value. The blocking characteristic as a function of the JTE dose is also discussed for the PiN rectifiers with and without interface charge. Project supported by the State Key Program of the National Natural Science Foundation of China (Grant No. 61234006), the Open Foundation of the State Key Laboratory of Electronic Thin Films and Integrated Devices, China (Grant No. KFJJ201301), and the National Science and Technology Major Project of the Ministry of Science and Technology, China (Grant No. 2013ZX02305-003).

  13. Genesis Model of Laozishan Geothermal Field, Subei Basin%苏北盆地老子山地热田成因模式

    Institute of Scientific and Technical Information of China (English)

    杨峰田; 庞忠和; 王彩会; 段忠丰; 罗璐; 李义曼

    2012-01-01

    老子山地热田是苏北盆地的典型地热田之一,阐明其成因模式对于该地热田的进一步开发和热水资源的可持续利用具有一定的指导意义.基于大地热流测试和水文地球化学方法对其进行了系统研究.结果表明:该区大地热流背景值为63.9 mW/m2,地热水与浅层地下水和地表水之间在水化学和同位素组成上存在明显差异.经分析,该地热系统属于中低温对流型.其补给区位于距地热田南部约60 km处的盱眙-张八岭一带的丘陵地区,热储温度为73~120℃,循环深度为2 350~4 200m,循环周期约为7 800 a,热水在区内NNE—SSW向与NW—SE向断裂的交汇处上涌,形成地热田.%Laozishan is a typical geothermal field in Subei Basin. We conducted a systematic study to explore into the genesis mechanism through heat flow measurement and hydrogeochemical investigation, for the purpose of further exploration and sustainable use of the geothermal resources. Results show that the background heat flow is 63. 9 mW/m2, and the hydrochemical and isotopic compositions of the thermal water are different from those of the shallow groundwater and surface water. Based on these data, the genesis model of the geothermal field has been postulated to be a low-medium temperature geothermal system of convective type. The recharge area is located in the Zhangbaling to the Xuyi mountain chain with a distance of about 60 km to the south of the geothermal field. The reservoir temperature of the geothermal field has been estimated to be 73 - 120 ℃ , with a water circulation depth of 2350-4200 m. The water age is about 7800 a. The thermal water flows upward in Laozishan area in the intersection zones of the faults striking NNE - SSW and NW - SE.

  14. A study of production/injection data from slim holes and large-diameter wells at the Takigami Geothermal Field, Kyushu, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Garg, S.K. [Maxwell Federal Div., Inc., San Diego, CA (United States); Combs, J. [Geo-Hills Associates, Los Altos Hills, CA (United States); Azawa, Fumio [Idemitsu Kosan Co. Ltd., Tokyo (Japan); Gotoh, Hiroki [Idemitsu Oita Geothermal Co. Ltd., Oita (Japan)

    1996-11-01

    Production and injection data from nine slim holes and sixteen large-diameter wells at the Takigami Geothermal Field, Kyushu, Japan were analyzed in order to establish relationships (1) between injectivity and productivity indices, (2) between productivity/injectivity index and borehole diameter, and (3) between discharge capacity of slim holes and large-diameter wells. Results are compared with those from the Oguni and Sumikawa fields. A numerical simulator (WELBOR) was used to model the available discharge rate from Takigami boreholes. The results of numerical modeling indicate that the flow rate of large-diameter geothermal production wells with liquid feedzones can be predicted using data from slim holes. These results also indicate the importance of proper well design.

  15. Subsidence monitoring in the Cerro Prieto geothermal field, B.C., Mexico; Monitoreo de la subsidencia en el campo geotermico de Cerro Prieto, B.C., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lira Herrera, Hector [Gerencia de Proyectos Geotermoelectricos, Comision Federal de Electricidad, Cerro Prieto, B.C. (Mexico)

    1999-04-01

    Since 1977, precise leveling surveys have been carried out to determine whether there have been vertical terrain displacements and the subsidence speed rate in the Cerro Prieto Geothermal field area. The elevation contours for each leveling show since 1962 that there was a basin that involves the geothermal field. The differences in the last three levelings show a generalized subsidence between Cerro Prieto (BN 10049) and Imperial faults (BN CD-14). [Spanish] A partir de 1977 se realizan trabajos de nivelacion de precision, con el fin de conocer si existen desplazamientos verticales del terreno y cual es la velocidad de subsidencia que existe en el area del Campo Geotermico de Cerro Prieto. Las configuraciones de cotas para cada uno de los anos nivelados, muestran que desde 1962 existe una cuenca que incluye al campo geotermico; la diferencia de cotas obtenidas en las tres ultimas nivelaciones, indican una subsidencia generalizada entre la Falla Cerro Prieto (BN 10049) y la Falla Imperial (BN CD-14).

  16. Cost model for geothermal wells applied to the Cerro Prieto geothermal field case, BC Abstract; Modelo de costeo de pozos geotermicos aplicado para el caso del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Vaca Serrano, Jaime M.E [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: jaime.vaca@cfe.gob.mx

    2008-01-15

    A project for drilling geothermal wells to produce electrical energy can be defined as a sequence of plans to get steam or geothermal fluids to satisfy a previously known demand, and, under the best possible conditions, to obtain payment. This paper presents a cost model for nine wells drilled at the Cerro Prieto geothermal field in 2005 and 2006 to supply steam to the power plants operating in the field. The cost model is based on the well cost, the initial steam production, the annual decline of steam, the drilling schedule and the break-even point for each well. The model shows the cost of steam by the ton and the sale price needed to determine the discount rate and the investment return time. [Spanish] Un proyecto de perforacion de pozos geotermicos puede definirse como una secuencia o sucesion de planes para obtener vapor o fluidos geotermicos destinados a satisfacer una demanda previamente determinada, que se emplearan principalmente para generar energia electrica, bajo las mejores condiciones para obtener un pago. Este trabajo presenta un modelo de costeo para nueve pozos en el campo geotermico de Cerro Prieto, que fueron perforados entre 2005 y 2006 como parte del suministro de vapor para las plantas generadoras que operan en este campo. El modelo de costeo se basa en el costo por pozo, la produccion inicial de vapor, la declinacion anual de vapor, los intereses de las obras de perforacion y el punto de equilibrio para cada pozo. Los resultados permiten conocer el costo de la tonelada de vapor y el precio de venta para determinar la tasa de descuento y el tiempo de retorno de la inversion.

  17. Space-Time Evolution of Seismicity in North-Western Geysers Geothermal Field and its Connection to Stimulation Processes

    Science.gov (United States)

    Leptokaropoulos, Konstantinos; Staszek, Monika; Lasocki, Stanislaw; Kwiatek, Grzegorz; Martinez-Garzon, Patricia

    2017-04-01

    The rising needs for energy along with the recent requirements for more efficient usage and exploitation of the deep underground have resulted to a growing scientific and public concern on related environmental impacts. Hydraulic fracturing that has been carried out during the last decades is occasionally connected with triggered and induced seismicity worldwide. Data from geothermal fields can be used as a proxy for shale gas exploitation associated seismicity since they are both tightly connected to hydraulic fracturing. For that reason we utilize 'The Geysers' data from the compiled SHEER (Shale Gas Exploration and Exploitation Induced Risks) database. The Geysers (California, USA) is the largest producing geothermal field in the world and has been sufficiently monitored and studied since the last decades. Seismic and technological data gathered during the past 40 years indicate a connection of seismic activity with the fluctuations of the injected fluid volume. In this study we verify and quantify this correlation by analyzing the data associated with 2 injection wells (Prati-9 and Prati-29) which covers a time period of approximately 7 years (from November 2007 to August 2014). The correlation between spatio-temporal seismicity evolution and variation of the injection data is performed by elaboration of original and smoothed time-series through specified statistical tools (cross correlation, binomial test to investigate significant rate changes, b-value variation). Our analysis indicate a short time delay of seismicity occurrence at distances larger than 200m from the injection well, whereas no evidence of significant correlation between injection rates and b-values was discovered. The obtained results are expected to contribute to a better comprehension of the role of hydraulic fracturing and the physical processes controlling seismogenesis in fluid injection sites. Acknowledgements: This work was supported within SHEER: "Shale Gas Exploration and

  18. Three-dimensional inversion of self-potential data used to constrain the pattern of groundwater flow in geothermal fields

    Science.gov (United States)

    Jardani, A.; Revil, A.; BolèVe, A.; Dupont, J. P.

    2008-09-01

    We propose an algorithm to invert self-potential signals measured at the ground surface of the Earth to localize hydromechanical disturbances or to the pattern of groundwater flow in geothermal systems. The self-potential signals result from the divergence of the streaming current density. Groundwater flow can be either driven by topography of the water table, free convection, or deformation of the medium. The algorithm includes the electrical resistivity distribution of the medium obtained independently by DC resistance tomography or electromagnetic methods or by coding the assumed geology in terms of distribution of the electrical resistivity accounting for the effect of the temperature and salinity distributions and possibly constraints from borehole measurements. Inversion of the distribution of the source current density from ground surface and borehole self-potential measurements is achieved by solving the inverse problem using Tikhonov regularization solutions that are compatible with the physics of the primary flow problem. By introducing assumptions regarding the smoothness or the compactness of the source and the three-dimensional distribution of the electrical resistivity of the system, the inverse problem can be solved in obtaining the three-dimensional distribution of the current source density in the ground. However, an annihilator can be added to the inverted source geometry without affecting the measured self-potential field. Annihilators can be obtained from boundary conditions. Synthetic models and a sandbox experiment are discussed to demonstrate the validity of the algorithm. An application is presented to the geothermal field of Cerro Prieto, Baja California, Mexico, using literature data. Inversion of the self-potential and resistivity data allows observing a plume of hot groundwater rising to the ground surface in the central part of the investigated area and discharging to the ground surface in the southwest part. The temperature anomaly

  19. Fracture mapping in the Soultz-sous-Forêts geothermal field using microearthquake locations

    Science.gov (United States)

    Michelet, Sophie; ToksöZ, M. Nafi

    2007-07-01

    In 2003, a massive hydraulic fracturing experiment was carried out at the European Geothermal Hot Dry Rock site at Soultz-sous-Forêts, France. The 2 week injection of water generated a high level of microseismic activity, triggering about 90,000 microearthquakes during and after the fluid injection. Of these, 21,000 events, detected at all stations, were located individually with a grid search algorithm to characterize the extent of the seismic zones and ultimately of the fracture network. The accuracy of these initial locations was around 70 m, not sufficient to map detailed fracture patterns. A precise relocation effort was undertaken to reduce the location uncertainties using three different techniques: joint hypocenter determination (JHD), collapsing and multiplet analysis. The collapsing method was added to the JHD results to further consolidate the hypocenters. On the other hand, a multiplet analysis was performed on the initial data set for identifying microearthquakes with similar waveforms and hence relocating relatively the correlated events. The delays in traveltime were computed by wavelet analysis and the events were relocated using a grid search algorithm. We found 7463 events whose seismograms correlated with a correlation coefficient of 0.8 or higher, most of which were doublets. Multiplets are horizontal tube-like structures with lengths from a hundred to several hundred meters striking along the direction of the maximum compressive horizontal stress. We interpret these structures as the preferential paths where fluid flow is largely confined. This hypothesis is reinforced by the good correlation in depth between the events and the fluid outflows observed in the well. Therefore we believe that these relocated events highlight the zones where the permeability of the reservoir is increased.

  20. GEOTHERMAL POWER GENERATION PLANT

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Tonya

    2013-12-01

    Oregon Institute of Technology (OIT) drilled a deep geothermal well on campus (to 5,300 feet deep) which produced 196oF resource as part of the 2008 OIT Congressionally Directed Project. OIT will construct a geothermal power plant (estimated at 1.75 MWe gross output). The plant would provide 50 to 75 percent of the electricity demand on campus. Technical support for construction and operations will be provided by OIT’s Geo-Heat Center. The power plant will be housed adjacent to the existing heat exchange building on the south east corner of campus near the existing geothermal production wells used for heating campus. Cooling water will be supplied from the nearby cold water wells to a cooling tower or air cooling may be used, depending upon the type of plant selected. Using the flow obtained from the deep well, not only can energy be generated from the power plant, but the “waste” water will also be used to supplement space heating on campus. A pipeline will be construction from the well to the heat exchanger building, and then a discharge line will be construction around the east and north side of campus for anticipated use of the “waste” water by facilities in an adjacent sustainable energy park. An injection well will need to be drilled to handle the flow, as the campus existing injection wells are limited in capacity.

  1. Geothermal Power Generation Plant

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Tonya [Oregon Inst. of Technology, Klamath Falls, OR (United States). Geo-Heat Center

    2013-12-01

    Oregon Institute of Technology (OIT) drilled a deep geothermal well on campus (to 5,300 feet deep) which produced 196°F resource as part of the 2008 OIT Congressionally Directed Project. OIT will construct a geothermal power plant (estimated at 1.75 MWe gross output). The plant would provide 50 to 75 percent of the electricity demand on campus. Technical support for construction and operations will be provided by OIT’s Geo-Heat Center. The power plant will be housed adjacent to the existing heat exchange building on the south east corner of campus near the existing geothermal production wells used for heating campus. Cooling water will be supplied from the nearby cold water wells to a cooling tower or air cooling may be used, depending upon the type of plant selected. Using the flow obtained from the deep well, not only can energy be generated from the power plant, but the “waste” water will also be used to supplement space heating on campus. A pipeline will be construction from the well to the heat exchanger building, and then a discharge line will be construction around the east and north side of campus for anticipated use of the “waste” water by facilities in an adjacent sustainable energy park. An injection well will need to be drilled to handle the flow, as the campus existing injection wells are limited in capacity.

  2. Upgrade of the synchronous data management system of the EAST poloidal field power supply

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Lili; Huang, Liansheng, E-mail: huangls@ipp.ac.cn; Fu, Peng; Gao, Ge; He, Shiying

    2016-11-15

    Highlights: • The upgraded synchronous data management system of EAST poloidal field power supply supports long-pulse data storage. • Slice storage mechanism on MDSplus has been adopted for quasi real-time data storage. • The state machine has been adopted for managing the system sequencer. • IEEE-1588 protocol via Ethernet for the synchronization of clock signal was detailed described. - Abstract: Poloidal field (PF) power supply is an important subsystem of the Experimental Advanced Superconducting Tokamak (EAST). The upgrade of the PF control system of EAST is a great improvement over the original data management system which could not meet the requirements necessary for experiments on synchronization, modularity and sampling rate. In order to better analyze the power operation performance, the Synchronization Data Management System (SDMS) needs to be upgraded as well. This upgrade is based on distributed data acquisition and an MDSPLUS database. It consists of three data acquisition nodes synchronized by an reference clock from the EAST central timing system that also provides the start trigger of the EAST pulse. After being processed by a signal conditioning unit, experimental signals are digitized and written into the database in MDSPLUS format. Multi-channel, multi-tasking and continuous data storage have been achieved by using multi-threading technology on a Linux operation system. The SDMS has been used on the server in PF control system for the entire 2015 EAST campaign. The SDMS has had good performance during experiments and convenient human-machine interface to satisfy the requirements of all the experiments.

  3. In-situ stress and fracture characterization for planning of a hydraulic stimulation in the Desert Peak Geothermal Field, NV

    Science.gov (United States)

    Hickman, S.; Davatzes, N. C.

    2009-12-01

    A suite of geophysical logs and a hydraulic fracturing stress measurement were conducted in well 27-15 in the Desert Peak Geothermal Field, Nevada, to constrain the state of stress and the geometry and relative permeability of natural fractures in preparation for development of an Enhanced Geothermal System (EGS) through hydraulic stimulation. Advanced Logic Technologies Borehole Televiewer (BHTV) and Schlumberger Formation MicroScanner (FMS) image logs reveal extensive drilling-induced tensile fractures, showing that the current minimum horizontal principal stress, Shmin, in the vicinity of well 27-15 is oriented 114 ± 17°. This orientation is consistent with down-dip extensional slip on a set of ESE and WNW dipping normal faults mapped at the surface. Similarly, all formations imaged in the BHTV and FMS logs include significant sub-populations of fractures that are well oriented for normal faulting given this direction of Shmin. Although the bulk permeability of the well is quite low, temperature and spinner flowmeter surveys reveal several minor flowing fractures. Some of these relatively permeable fractures are well oriented for normal faulting, in addition to fluid flow that is preferentially developed at low-angle formation boundaries. A hydraulic fracturing stress measurement conducted at the top of the intended stimulation interval (931 m) indicates that the magnitude of Shmin is 13.8 MPa, which is 0.609 of the calculated vertical (overburden) stress at this depth. Given the current water table depth (122 m below ground level), this Shmin magnitude is somewhat higher than expected for frictional failure on optimally oriented normal faults given typical laboratory measurements of sliding friction (Byerlee’s Law). Coulomb failure calculations assuming cohesionless pre-existing fractures with coefficients of friction of 0.6 or higher (consistent with Byerlee’s Law and with tests on representative core samples from nearby wells) indicate that shear

  4. Geologic and Engineering Characterization of East Ford Field, Reeves County, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, Shirley P.; Flanders, William A.; Guzman, Jose I.; Zirczy, Helena

    1999-08-16

    The objective of this Class III project is to demonstrate that detailed reservoir characterization of slope and basin clastic reservoirs in sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover a higher percentage of the original oil in place through geologically based field development. The project focused on reservoir characterization of the East Ford unit, a representative Delaware Mountain Group field that produces from the upper Bell Canyon Formation (Ramsey Sandstone). The field, discovered in 1960, is operated by Oral Petco, Inc., as the East Ford unit: it contained an estimated 18.4 million barrels (MMbbl) of original oil in place.

  5. Hydrochemical-isotopic and hydrogeological conceptual model of the Las Tres Vı´rgenes geothermal field, Baja California Sur, México

    Science.gov (United States)

    Portugal, E.; Birkle, P.; Barragán R, R. M.; Arellano G, V. M.; Tello, E.; Tello, M.

    2000-09-01

    Based on geological, structural, hydrochemical and isotopic data, a hydrogeological conceptual model for the geothermal reservoir, shallow wells and springs at the Las Tres Vı´rgenes geothermal field and its surroundings is proposed. The model explains the genesis of different types of thermal and cold groundwater in the NW (El Azufre Valley, Las Tres Vı´rgenes and Aguajito complex), NE (Reforma complex) and S (Sierra Mezquital) areas. Shallow groundwater of sulfate type in the NW zone is explained by the rise of CO 2-H 2S vapor from a shallow magma chamber and the subsequent heating up of a shallow aquifer. Vertical communication between the reservoir and the surface is facilitated by a series of extensional, NW-SE-trending normal faults, forming the graben structures of the Santa Rosalı´a Basin. Low-permeability characteristics of the geological formations of the study area support the hypothesis of a fracture and fault-dominated, subterranean-flow circulation system. The Na- (Cl-HCO 3) composition of springs in the NE and SE zones indicates influence of ascending geothermal fluids, facilitated by radial fault systems of the Reforma caldera and probably the existence of a shallow magma chamber. Close to the surface, the rising geothermal fluids are mixed up with meteoric water from a shallow aquifer. The Las Tres Vı´rgenes and the Reforma complex are separated by younger, N-S-trending lateral shearing faults, such as the Cimarrón fault; such disposition explains the genesis of different hydrogeological flow regimes on both sides. HCO 3-type surface water from the southern zone between San Ignacio and Mezquital is of typical meteoric origin, with no influence of geothermal fluids. Due to arid climatic conditions in the study zone, recent recharge in the geothermal area seems improbable; thus, recent interaction between the surface and the geothermal reservoir can be excluded. Furthermore, isotopic and hydrochemical data exclude the presence of marine

  6. Geological determination of the limits, area and volume of the geothermal reservoir of the Los Humeros geothermal field, Puebla, Mexico; Determinacion geologica de los limites, area y volumen del yacimiento geotermico de Los Humeros, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Castillo Hernandez, Daniel [Gerencia de Proyectos Geotermoelectricos, Comision Federal de Electricidad, Morelia, Michoacan (Mexico)

    1999-08-01

    A geologic analysis to determine the limits, area and volume of the exploitable reservoir of the Los Humeros Geothermal Field, in Puebla, Mexico was carried out. We defined the structural boundaries, both at surface and at deep that seem to control the distribution of the fluids of high enthalpy and favor or limit the production of steam. With 40 wells drilled to date, an average thickness of the lithological producer Unit of 1 163 m has been estimated. A surface of 12.54 km{sup 2} was calculated, that with the estimated thickness, gives a volume of the reservoir of 14.6 km{sup 3}. We consider that there are two main production sectors in the Geothermal Field: The Central Collapse and The Mastaloya Corridor. [Spanish] Se realizo un analisis geologico para determinar los limites, area y volumen del yacimiento explotable del campo geotermico de Los Humeros en Puebla, Mexico. Se definen las barreras estructurales, tanto superficiales como del subsuelo, que controlan la distribucon de los fluidos de alta entalpia que favorecen o limitan la produccion de vapor. Con los 40 pozos perforados hasta la fecha, se estima un espesor promedio de la unidad productora de 1 163 m. Se calculo una superficie de 12.54 km{sup 2}, la que con el espesor mencionado, da un volumen del yacimiento de 14.6 km{sup 3}. Se plantea que dentro del campo existen dos sectores principales de produccion. El Colapso Central y el Corredor de Mastaloya.

  7. Basic research needed for the development of geothermal energy

    Energy Technology Data Exchange (ETDEWEB)

    Aamodt, R.L.; Riecker, R.E.

    1980-10-01

    Basic research needed to facilitate development of geothermal energy is identified. An attempt has been made to make the report representative of the ideas of productive workers in the field. The present state of knowledge of geothermal energy is presented and then specific recommendations for further research, with status and priorities, are listed. Discussion is limited to a small number of applicable concepts, namely: origin of geothermal flux; transport of geothermal energy; geothermal reservoirs; rock-water interactions, and geophysical and geochemical exploration.

  8. Results of vertical seismic profiling at Well 46-28, Rye Patch Geothermal Field, Pershing County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Feighner, M.A.; Daley, T.M.; Majer, E.L.

    1998-02-25

    A Vertical Seismic Profile (VSP) was recorded in Rye Patch by LBNL between December 11 and December 13, 1997. Figure 1 shows the location of the Rye Patch Geothermal Field with Well 46-28 located within the marked Rye Patch Anomaly. The VSP in Well 46-28 used a vibroseis source and a single-level, high temperature, hydraulic wall-locking, 3-component seismometer. The vibroseis source was a Mertz P-wave vibrator. The source sweep was 10 Hz to 80 Hz, 10 seconds long, with a 0.2 s cosine taper. The borehole geophone was an SSC model LVHK 6001 using 14 Hz geophones. The recording system was a Geometrics Strataview. Six data channels were recorded: the three geophones, the source pilot, the vibrator reference and the vibrator baseplate accelerometer. The record length was 12,288 samples at a 1 ms sample rate, giving a 2.3 s correlated record length. A 10 Hz low cut filter was used and no high cut filter was used except the anti-alias filter. Results are described.

  9. Analysis of P- and S-wave VSP (vertical seismic profile) data from the Salton Sea Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Daley, T.M.

    1987-09-01

    To understand any geophysical data, geologic information is necessary. This thesis will begin with a summary of the geology of the Salton Trough region and the Salton Sea Geothermal Field (SSGF). The information available from the SSSDP will also be summarized. After the geologic summary, the design of the VSP will be discussed, including acquisition equipment and procedures. The data processing procedures and software used will be discussed as a separate section. Processing procedures will also be described at various times in the thesis where more specialized procedures are used. Data analysis makes up the bulk of the thesis and it is divided into a number of sections detailing the basic VSP interpretation, the anisotropy analysis and the fracture detection and orientation analysis. A combined interpretation of the results, with probable geologic causes for observed events, is presented as a separate section from the data analysis. Finally, a summary of results for each of the goals stated above will be given. The reader should note that a large volume of data were collected and various display methods were used (from the standard wiggle-trace to three-component hodographs). Much of these data are left in the appendices with important or representative figures given in the body of the thesis. Also given in the appendices are listings of FORTRAN programs developed in conjunction with the thesis work. 46 refs., 63 figs., 12 tabs.

  10. Modeling vapor dominated geothermal reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Marconcini, R.; McEdwards, D.; Neri, G.; Ruffilli, C.; Schroeder, R.; Weres, O.; Witherspoon, P.

    1977-09-12

    The unresolved questions with regard to vapor-dominated reservoir production and longevity are reviewed. The simulation of reservoir behavior and the LBL computer program are discussed. The geology of Serrazzano geothermal field and its reservoir simulation are described. (MHR)

  11. Engineered Geothermal System Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Petty, Susan

    2014-06-19

    In June 2009, AltaRock Energy began field work on a project supported by the U.S. Department of Energy entitled “Use of Multiple Stimulations to Improve Economics of Engineered Geothermal Systems in Shallow High Temperature Intrusives.” The goal of the project was to develop an Engineered Geothermal System (EGS) in the portion of The Geysers geothermal field operated by the Northern California Power Agency (NCPA). The project encountered several problems while deepening Well E-7 which culminated in the suspension of field activities in September 2009. Some of the problems encountered are particular to The Geysers area, while others might be encountered in any geothermal field, and they might be avoided in future operations.

  12. The Colorado MESA Program and CU-LASP: A Model for After School Program/Research Institution Collaboratives

    Science.gov (United States)

    Nelson, G.; Cobabe-Ammann, E.

    2004-12-01

    Colorado MESA is an after school program operating throughout the state with a long track record in promoting science, math and engineering education to largely underserved K-12 student populations. Currently, 81 percent of MESA students are from groups underrepresented in the math/science careers, and 85 percent of MESA students come from low- and moderate-income families. Through a combination of weekly student programs, field trips to universities and industry partners, family orientations, individual academic counseling and required curriculum, Colorado MESA offers an opportunity for students to explore STEM subjects and careers that they might not otherwise have access to - with tangible results. In the Colorado MESA Class of 2003, 97 percent of students planned on entering college this fall, with 86 percent indicating that they will enroll in math/science-based majors. In the last year, the University of Colorado's Laboratory for Atmospheric and Space Physics, a large space and earth sciences institute, has relied on the Colorado MESA program as its primary K-12 partner in Education and Public Outreach. LASP incorporates MESA into its proposal writing opportunities, from E/PO additions to individual research proposals to mission-level educational programs. In addition to funding opportunities, LASP provides scientists and engineers in a variety of contexts and content areas, while MESA works to incorporate those resources into their after school programs. The interface between the after school programs and the research institution requires ongoing communication and coordination in order to evaluate and fine-tune curriculum and activities based on feedback from MESA advisors and teachers. Currently, the MESA/LASP partnership has funded programs in astrobiology, planetary sciences and engineering.

  13. Cementing of geothermal wells. Progress report No. 12, January-March, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1979-08-01

    Work to implement the program plan for the development of improved high temperature cementing materials for geothermal wells is continuing. Results from initial tests in the Dynamic Brine Exposure Testing Apparatus (D-BETA) are available. Based upon initial data, the rate at which cement coupons undergo change in the D-BETA is between that of the static tests and the dynamic exposures at East Mesa. Several cementing compositions have been formulated with chemical, physical and mechanical properties to withstand the existing geothermal conditions. The pumpability of three formulations has been demonstrated and the materials have been submitted to NBS for additional evaluation. The effect of Al/sub 2/O/sub 3/, Fe/sub 2/O/sub 3/, SO/sub 3/, Na/sub 2/CO/sub 3/ and Na/sub 2/SO/sub 4/ on different binders were studied at Colorado School of Mines. The results were found to range from deleterious to beneficial. Phosphate-bonded cements have been produced at the University of Rhode Island from a glass containing 7% Na/sub 2/O, 24% CaO, 24% Al/sub 2/O/sub 3/ and 45% SiO/sub 2/. Preliminary tests indicate that the material sets in several hours and appears to have some high temperature stability. Tests performed on hydrothermal cements indicate six formulations that are pumpable as long as three hours at 316/sup 0/C. Two formulations, Al/sub 2/O/sub 3/ and ZrO/sub 2/, have been chosen for use at temperatures above 300/sup 0/C. Polymer concentrates containing cement fillers have been found to be hydrothermally stable in 300/sup 0/C brine. Recommended standards for evaluating geothermal well cements have been developed by NBS. (MHR)

  14. Hydraulic fracturing research in east Texas; Third GRI staged field experiment

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, B.M. (S.A. Holditch and Associates, Inc. (US))

    1992-01-01

    This paper presents results from results from research conducted on the third Gas Research inst. (GRI) staged field experiment (SFE) well. Research well SFE No. 3 was drilled as part of a field-based research program conducted in east Texas during the past 7 years. Most of the work before SFE No. 3 involved the Travis Peak formation; however, the Cotton Valley sandstone was the primary research target for this well. SFE no. 3 is the last in a series of research wells planned for east Texas. A fourth SFE is being conducted in the Frontier formation of southwestern Wyoming. Data on SFE wells are collected from whole cores, openhole geophysical logs, in-situ stress measurements, production and pressure-transient tests, fracture stimulation treatments, fracture-diagnostic measurements, and postfracture performance tests. Test data then are analyzed by research scientists, geologists, and engineers to describe the reservoir and hydraulic fracture fully.

  15. Breakdown of doublet recirculation and direct line drives by far-field flow in reservoirs: implications for geothermal and hydrocarbon well placement

    Science.gov (United States)

    Weijermars, R.; van Harmelen, A.

    2016-07-01

    An important real world application of doublet flow occurs in well design of both geothermal and hydrocarbon reservoirs. A guiding principle for fluid management of injection and extraction wells is that mass balance is commonly assumed between the injected and produced fluid. Because the doublets are considered closed loops, the injection fluid is assumed to eventually reach the producer well and all the produced fluid ideally comes from stream tubes connected to the injector of the well pair making up the doublet. We show that when an aquifer background flow occurs, doublets will rarely retain closed loops of fluid recirculation. When the far-field flow rate increases relative to the doublet's strength, the area occupied by the doublet will diminish and eventually vanishes. Alternatively, rather than using a single injector (source) and single producer (sink), a linear array of multiple injectors separated by some distance from a parallel array of producers can be used in geothermal energy projects as well as in waterflooding of hydrocarbon reservoirs. Fluid flow in such an arrangement of parallel source-sink arrays is shown to be macroscopically equivalent to that of a line doublet. Again, any far-field flow that is strong enough will breach through the line doublet, which then splits into two vortices. Apart from fundamental insight into elementary flow dynamics, our new results provide practical clues that may contribute to improve the planning and design of doublets and direct line drives commonly used for flow management of groundwater, geothermal and hydrocarbon reservoirs.

  16. Correlation of wireline log characteristics with hydrothermal alteration and other reservoir properties of the Salton Sea and Westmorland geothermal fields, Imperial Valley, California, USA

    Energy Technology Data Exchange (ETDEWEB)

    Muramoto, F.S.; Elders, W.A.

    1984-05-01

    A detailed study of wireline logs from 11 wells in the Salton Sea and Westmorland geothermal systems was undertaken in order to determine the effects of hydrothermal alteration on the response of electrical and gamma-gamma density well logs. For the Salton Sea geothermal field, definite correspondence between log responses and hydrothermal mineralogy is evident, which in turn is related to the physical properties of the rocks. Three hydrothermal and one unaltered zone can be identified from log data on shales. These are: (1) the unaltered montmorillonite zone (<100/sup 0/ to 190/sup 0/C); (2) the illite zone (100/sup 0/ to 190/sup 0/C to 230/sup 0/ to 250/sup 0/C); (3) the chlorite zone (230/sup 0/ to 250/sup 0/C to 290/sup 0/ to 300/sup 0/C); and (4) the feldspar zone (>290/sup 0/ to 300/sup 0/C). The characteristic responses on well logs by which these zones are identified result primarily from changes in clay mineralogy of the shales and increases in density with progressive hydrothermal metamorphism. In the Westmorland geothermal field, differentiating mineral zones from log responses was only partially successful. However, analyses of both well log and petrologic data for wells Landers 1 and Kalin Farms 1 suggest that the former is heating up and the latter is cooling.

  17. A Study of Production/Injection Data from Slim Holes and Large-Diameter Wells at the Okuaizu Geothermal Field, Tohoku, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Renner, Joel Lawrence; Garg, Sabodh K.; Combs, Jim

    2002-06-01

    Discharge from the Okuaizu boreholes is accompanied by in situ boiling. Analysis of cold-water injection and discharge data from the Okuaizu boreholes indicates that the two-phase productivity index is about an order of magnitude smaller than the injectivity index. The latter conclusion is in agreement with analyses of similar data from Oguni, Sumikawa, and Kirishima geothermal fields. A wellbore simulator was used to examine the effect of borehole diameter on the discharge capacity of geothermal boreholes with two-phase feedzones. Based on these analyses, it appears that it should be possible to deduce the discharge characteristics of largediameter wells using test data from slim holes with two-phase feeds.

  18. Geothermal industry assessment

    Energy Technology Data Exchange (ETDEWEB)

    1980-07-01

    An assessment of the geothermal industry is presented, focusing on industry structure, corporate activities and strategies, and detailed analysis of the technological, economic, financial, and institutional issues important to government policy formulation. The study is based principally on confidential interviews with executives of 75 companies active in the field. (MHR)

  19. Scientific Profile of Pharmacology, Toxicology and Pharmaceutics Fields in Middle East Countries: Impacts of Iranian Scientists

    OpenAIRE

    2010-01-01

    In the present investigation, a statistical analysis was conducted to evaluate the production of scientific papers in the fields of Pharmacology, Toxicology and Pharmaceutical during a period of 1996-2007. The study identified the most active countries in the Middle East in comparison with some more developed countries, in which the most scientific impacts have been exerted. Our screenings through the most accessed data bases revealed that USA, Japan, UK and Germany are the leading countries ...

  20. GEOTHERMICS GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20112453 Li Qing (First Design and Research Institute,Ministry of Mechanical Industry, Bengbu 233000, China); Li Yixiang Application of Shallow Geothermal Energy Resources in the Hefei Area(Geology

  1. Geothermal Websites

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Tonya

    2005-03-01

    The Internet has become such an important part of our every day life. It can be used to correspond with people across the world, a lot faster than to send a letter in the mail. The Internet has a wealth of information that is available to anybody just by searching for it. Sometimes you get more information than you ever wanted to know and sometimes you can’t find any information. This paper will only cover a small portion of the websites and their links that have geothermal information concerning reservoir engineering, enhanced geothermal systems, hot dry rock and other aspects of geothermal. Some of the websites below are located in the US others international, such as, geothermal associations, and websites where you can access publications. Most of the websites listed below also have links to other websites for even more information.