Sample records for active geothermal systems

  1. Geothermal systems

    NASA Technical Reports Server (NTRS)

    Mohl, C.

    1978-01-01

    Several tasks of JPL related to geothermal energy are discussed. The major task is the procurement and test and evaluation of a helical screw drive (wellhead unit). A general review of geothermal energy systems is given. The presentation focuses attention on geothermal reservoirs in California, with graphs and charts to support the discussion. Included are discussions on cost analysis, systems maintenance, and a comparison of geothermal and conventional heating and cooling systems.

  2. Modeling of geothermal systems

    SciTech Connect

    Bodvarsson, G.S.; Pruess, K.; Lippmann, M.J.

    1985-03-01

    During the last decade the use of numerical modeling for geothermal resource evaluation has grown significantly, and new modeling approaches have been developed. In this paper we present a summary of the present status in numerical modeling of geothermal systems, emphasizing recent developments. Different modeling approaches are described and their applicability discussed. The various modeling tasks, including natural-state, exploitation, injection, multi-component and subsidence modeling, are illustrated with geothermal field examples. 99 refs., 14 figs.

  3. Cordon Caulle: an active volcanic-geothermal extensional system of Southern Andes of Chile

    NASA Astrophysics Data System (ADS)

    Sepulveda, F.

    2013-05-01

    Cordon Caulle (CC; 40.5° S) is an active volcanic-geothermal system of the Southern Volcanic Zone (SVZ; 37°-44°S). Morphologically, the CC system is a 6 km x 13 km volcanic plateau bordered by NW-trending structures, limited by Puyehue Volcano to the SE and by Caldera Nevada Caldera to the NW. While the SVZ is dominantly basaltic, CC is unique in that it has produced a wide compositional spectrum from basalt to rhyolite. The most recent volcanic activity of Puyehue-CC (last 70 ky) is dominantly silicic, including two historic fissure eruptions (1921-1922; 1960) and a recent central eruption from Puyehue Volcano (2011). Abnormally silicic volcanism was formerly attributed to a localized compression and long-term magma residence and differentiation, resulting from the NW orientation of underlying CC structures with respect to a NE-oriented ?1 (linked to regional strike-slip stress state). However, later studies, including examination of morpho-tectonic features; detailed structural analysis of the 1960 eruption (triggered by Mw 9.5 1960 Chilean Earthquake); InSAR deformation and gravity surveys, point to both historic and long-term extension at CC with ?hmax oriented NNW to NW. The pre-2011 (i.e. Puyehue Volcano eruption) geothermal features of CC included boiling hot springs and geysers (Caldera Nevada) and fumaroles (CC and Puyehue Volcano). Both water and gas chemistry surveys were undertaken to assess the source fluid composition and equilibrium temperature. The combination of water and gas geothermometers led to a conceptual model of a stratified geothermal reservoir, with shallow, low-chloride, steam-heated aquifers equilibrated at temperatures between 150°-180°C, overlying a deeper, possibly dominated reservoir with temperatures in excess of 280°C. Gas chemistry also produced the highest He ratios of the SVZ, in agreement with a relatively pure, undiluted magmatic signature and heat source fueling the geothermal system. Other indicators such as N2/Ar ratios indicated two sources of gases: a geothermal source (i.e. associated with benign, neutral geothermal fluids) at the centre of the CC, and a more volcanic-magmatic (i.e. associated with acidic, oxidising fluids) source towards the SE (Puyehue Volcano), in agreement with the presence of an active volcanic system. The combination of silicic volcanism, extension and high-temperature geothermal activity of CC pose some resemblance to high-temperature geothermal systems of the Taupo Volcanic Zone, North Island, New Zealand. In this setting, recent studies show that rifting (i.e. extension) can be a magma-assisted process. In a similar fashion, I hypothesize that a deep (> 2 km), NW-elongate magma reservoir can account for the development of NW-trending structures at CC, and the existence of central volcanism at both ends of the CC.

  4. Geotherm: the U.S. geological survey geothermal information system

    USGS Publications Warehouse

    Bliss, J.D.; Rapport, A.

    1983-01-01

    GEOTHERM is a comprehensive system of public databases and software used to store, locate, and evaluate information on the geology, geochemistry, and hydrology of geothermal systems. Three main databases address the general characteristics of geothermal wells and fields, and the chemical properties of geothermal fluids; the last database is currently the most active. System tasks are divided into four areas: (1) data acquisition and entry, involving data entry via word processors and magnetic tape; (2) quality assurance, including the criteria and standards handbook and front-end data-screening programs; (3) operation, involving database backups and information extraction; and (4) user assistance, preparation of such items as application programs, and a quarterly newsletter. The principal task of GEOTHERM is to provide information and research support for the conduct of national geothermal-resource assessments. The principal users of GEOTHERM are those involved with the Geothermal Research Program of the U.S. Geological Survey. Information in the system is available to the public on request. ?? 1983.

  5. Active Seismics to Determine Reservoir Characteristics of a Hot Dry Rock Geothermal System

    SciTech Connect

    Green, A.S.P.; Baria, R.

    1987-01-20

    Since 1981 three wells have been drilled to depths of between 2.0 and 2.6 km in the Carnmenellis granite, Cornwall, England in order to create a HDR geothermal system. These wells are separated by between 150 and 300 m and have been hydraulically connected by massive injections of both water and viscous gel (50 cpoise). Passive microseismic monitoring of the hydraulic stimulation and circulation experiments has been used since 1982 to determine the size and structure of the reservoir, and monitor its growth. The active seismic survey techniques of cross-hole seismics and vertical seismic profiling (VSP) have been introduced to complement the passive microseismic monitoring in characterizing the reservoir. The cross-hole seismic surveys indicate that the microseismicity defines the area of joint dilation. The attenuation of high frequencies in the region of microseismicity suggests that the reservoir is composed of a complex zone of cracks rather than a single large fracture. VSP surveys also show a good agreement between the microseismically defined reservoir and seismic signal attenuation. Recent improvements in hardware, computer processing and interpretation indicate that active seismics will play an increasingly important part in mapping and understanding geothermal reservoirs. 11 figs., 10 refs.

  6. Geothermal activities in Central America

    Microsoft Academic Search

    J. T. Whetten; R. J. Hanold

    1985-01-01

    The Agency for International Development is funding a new program in energy and minerals for Central America. Geothermal energy is an important component. A country-wide geothermal assessment has started in Honduras, and other assessment activities are in progress or planned for Costa Rica, El Salvador, Guatemala, and Panama. Instrumentation for well logging has been provided to Costa Rica, and a

  7. Geothermal Systems for School.

    ERIC Educational Resources Information Center

    Dinse, David H.

    1998-01-01

    Describes an award-winning school heating and cooling system in which two energy-efficient technologies, variable-flow pumping and geothermal heat pumps, were combined. The basic system schematic and annual energy use and cost savings statistics are provided. (GR)

  8. Solar–geothermal hybrid system

    Microsoft Academic Search

    Álvaro Lentz; Rafael Almanza

    2006-01-01

    The Cerro Prieto Geothermal Power Plant is located in the northwest of Mexico, lat. 32°39?, long. 115°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

  9. Active Seismics to Determine Reservoir Characteristics of a Hot Dry Rock Geothermal System

    Microsoft Academic Search

    A. S. P. Green; R. Baria

    1987-01-01

    Since 1981 three wells have been drilled to depths of between 2.0 and 2.6 km in the Carnmenellis granite, Cornwall, England in order to create a HDR geothermal system. These wells are separated by between 150 and 300 m and have been hydraulically connected by massive injections of both water and viscous gel (50 cpoise). Passive microseismic monitoring of the

  10. Molybdenum mineralization in an active geothermal system, Valles caldera, New Mexico

    SciTech Connect

    Hulen, J.B.; Nielson, D.L.; Goff, F.; Gardner, J.N.; Charles, R.W.

    1987-08-01

    Shallow, sub-ore-grade molybdenite mineralization has been discovered in the active, high-temperature geothermal system penetrated by Continental Scientific Drilling Program corehole VC-2A at Sulfur Springs, in the western ring-fracture zone of the Valles caldera, New Mexico. This mineralization is hosted by fractured, quartz-sericitized, intracaldera ash-flow tuffs younger than 1.12 Ma. The molybdenite is an unusual, poorly crystalline variety that occurs in vuggy veinlets and breccia cements also containing quartz, sericite (illite), pyrite, and fluorite, as well as local sphalerite, rhodochrosite, and chalcopyrite. Fluid-inclusion data suggest that this assemblage was deposited from very dilute solutions at temperatures near 200/sup 0/C. Geochemical modeling indicates that under restricted pH and fO/sub 2/ conditions at 200/sup 0/C, the molybdenite and associated phases would be in equilibrium with hydrothermal fluids now circulating in the deep subsurface. The shallow molybdenite zone intersected in VC-2A may be the near-surface expression of deep, Climax-type stockwork molybdenum mineralization.

  11. Geothermal activities in Central America

    SciTech Connect

    Whetten, J.T.; Hanold, R.J.

    1985-09-11

    The Agency for International Development is funding a new program in energy and minerals for Central America. Geothermal energy is an important component. A country-wide geothermal assessment has started in Honduras, and other assessment activities are in progress or planned for Costa Rica, El Salvador, Guatemala, and Panama. Instrumentation for well logging has been provided to Costa Rica, and a self-contained logging truck will be made available for use throughout Central America. An important objective of this program is to involve the private sector in resource development. 4 refs., 3 figs.

  12. Induced Microseismic Activity in non Pressure Stimulated Geothermal System - an Example From Southern Germany

    NASA Astrophysics Data System (ADS)

    Wassermann, J. M.; Megies, T.

    2011-12-01

    In order to be efficient in selling heat and electric power, the most favorable locations for deep geothermal power plants are in close proximity to urbanized areas. This advantage bears the inherent danger of induced earthquakes especially during the stimulation and production phase of enhanced geothermal systems, which at least are partially felt in the near surroundings. Felt earthquakes, however, severely reduce the level of acceptance of residents close to the plant. The Bavarian Molasse basin is characterized by its highly permeable, deep groundwater bearing limestone layers. This high permeability permits the abdication of pressure stimulation of the geothermal reservoir and makes the close proximity to the densely populated area around Munich possible. In addition to this favorable production conditions, the Bavarian Molasse Basin is being considered as generally aseismic. In contrast to this obvious advantages five Ml > 2.0 events south of Munich which were felt by local residents attracted public attention. These events were located in the vicinity of a geothermal plant that took up production about half a year earlier. In the last two years a temporary network was set up that recorded more than 80 events with magnitudes mainly ranging from Ml -0.5 to 1.5. Events below magnitude 1.5 could not be detected and located prior to the production stage of the geothermal plant in the main network of the local earthquake service Erdbebendienst Bayern. Still, the exact mechanism leading to the seismicity remains unknown. Most likely the orientation of pre-existing faults, which are pierced by the open-hole part of wells with respect to present stress field and the volume of re-injected cold water play a key role in understanding the mechanisms leading to the observed seismicity. Within the framework of a project financed by the German federal ministry of Environment, further field experiments are conducted to address these open questions and test some working hypotheses. At two geothermal projects in comparable settings pre-production data is acquired in local seismometer networks to facilitate a comparison of possible microseismicity during production stages with natural background microseismicity.

  13. A geothermal AMTEC system

    SciTech Connect

    Schuller, M.J. [Phillips Lab. Power and Thermal Lab., Kirtland AFB, NM (United States); LeMire, R.A. [ORION International Technologies, Inc., Albuquerque, NM (United States); Horner-Richardson, K. [Thermacore, Inc., Lancaster, PA (United States)

    1995-12-31

    The Phillips Laboratory Power and Thermal Management Division (PL/VTP), with the support of ORION International Technologies, is investigating new methods of advanced thermal to electric power conversion for space and terrestrial applications. The alkali metal thermal-to-electric converter (AMTEC), manufactured primarily by Advanced Modular Power Systems (AMPS) of Ann Arbor, MI, has reached a level of technological maturity which would allow its use in a constant, unattended thermal source, such as a geothermal field. Approximately 95,000 square miles in the western United States has hot dry rock with thermal gradients of 60 C/km and higher. Several places in the United States and the world have thermal gradients of 500 C/km. Such heat sources represent an excellent thermal source for a system of modular power units using AMTEC devices to convert the heat to electricity. AMTEC cells using sodium as a working fluid require heat input at temperatures between 500 and 1,000 C to generate power. The present state of the art is capable of 15% efficiency with 800 C heat input and has demonstrated 18% efficiency for single cells. This paper discusses the basics of AMTEC operation, current drilling technology as a cost driver, design of modular AMTEC power units, heat rejection technologies, materials considerations, and estimates of power production from a geothermal AMTEC concept.

  14. Computerized international geothermal information systems

    SciTech Connect

    Phillips, S.L.; Lawrence, J.D.; Lepman, S.R.

    1980-03-01

    The computerized international geothermal energy information system is reviewed. The review covers establishment of the Italy - United States linked data centers by the NATO Committee on Challenges of Modern Society, through a bilateral agreement, and up to the present time. The result of the information exchange project is given as the bibliographic and numerical data available from the data centers. Recommendations for the exchange of computerized geothermal information at the international level are discussed.

  15. Mapping of faults activated by the stimulation of the Basel enhanced geothermal system

    NASA Astrophysics Data System (ADS)

    Deichmann, N.; Kraft, T.; Evans, K. F.

    2012-04-01

    High-precision relative location procedures of the stronger seismic events (0.7 < ML < 3.4), based on cross-correlations of signals recorded by a six-sensor borehole array and numerous surface stations in the immediate epicentral area, show that clustering of hypocenters on different spatial scales is a dominant feature of the microseismicity induced by the stimulation of enhanced geothermal reservoir in Basel. In line with the fact that many of the observed earthquakes form clusters of similar events, several focal mechanisms are also nearly identical to each other. A comparison between the high-precision relative locations of the events within each cluster and the focal mechanisms often shows a good coincidence of the hypocentral distribution with one of the nodal planes of the focal mechanism. In some cases, the spatial extent of the individual clusters is limited to a few meters, which suggests that the corresponding events represent repeated slip with partial stress drop as pore pressures increase with time. In other cases, that include some of the stronger events (ML > 2), the dimension of the individual clusters can amount to several 100 meters, and the activity within these clusters can extend over several days. Given that the orientation of many fault segments identified in this way deviates significantly from the overall orientation of the seismic cloud, these results reveal a complex internal structure of the flow paths in the rock volume stimulated by the water injection.

  16. Boise geothermal district heating system

    SciTech Connect

    Hanson, P.J.

    1985-10-01

    This document describes the Boise geothermal district heating project from preliminary feasibility studies completed in 1979 to a fully operational system by 1983. The report includes information about the two local governments that participated in the project - the City of Boise, Idaho and the Boise Warm Springs Water District. It also discusses the federal funding sources; the financial studies; the feasibility studies conducted; the general system planning and design; design of detailed system components; the legal issues involved in production; geological analysis of the resource area; distribution and disposal; the program to market system services; and the methods of retrofitting buildings to use geothermal hot water for space heating. Technically this report describes the Boise City district heating system based on 170/sup 0/F water, a 4000 gpm production system, a 41,000 foot pipeline system, and system economies. Comparable data are also provided for the Boise Warm Springs Water District. 62 figs., 31 tabs.

  17. Monitoring Biological Activity at Geothermal Power Plants

    SciTech Connect

    Peter Pryfogle

    2005-09-01

    The economic impact of microbial growth in geothermal power plants has been estimated to be as high as $500,000 annually for a 100 MWe plant. Many methods are available to monitor biological activity at these facilities; however, very few plants have any on-line monitoring program in place. Metal coupon, selective culturing (MPN), total organic carbon (TOC), adenosine triphosphate (ATP), respirometry, phospholipid fatty acid (PLFA), and denaturing gradient gel electrophoresis (DGGE) characterizations have been conducted using water samples collected from geothermal plants located in California and Utah. In addition, the on-line performance of a commercial electrochemical monitor, the BIoGEORGE?, has been evaluated during extended deployments at geothermal facilities. This report provides a review of these techniques, presents data on their application from laboratory and field studies, and discusses their value in characterizing and monitoring biological activities at geothermal power plants.

  18. Chelated Indium Activable Tracers for Geothermal Reservoirs

    E-print Network

    Stanford University

    SGP-TR-99 Chelated Indium Activable Tracers for Geothermal Reservoirs Constantinos V. Indium was se1ecti:d to be the most promising activable tracer. The thermal stability of indium tracer of the soluble indium concentration was made as a f'unction of time by neutron activation analysis. From the data

  19. Geothermal activity helps life survive glacial cycles

    PubMed Central

    Fraser, Ceridwen I.; Terauds, Aleks; Smellie, John; Convey, Peter; Chown, Steven L.

    2014-01-01

    Climate change has played a critical role in the evolution and structure of Earth’s biodiversity. Geothermal activity, which can maintain ice-free terrain in glaciated regions, provides a tantalizing solution to the question of how diverse life can survive glaciations. No comprehensive assessment of this “geothermal glacial refugia” hypothesis has yet been undertaken, but Antarctica provides a unique setting for doing so. The continent has experienced repeated glaciations that most models indicate blanketed the continent in ice, yet many Antarctic species appear to have evolved in almost total isolation for millions of years, and hence must have persisted in situ throughout. How could terrestrial species have survived extreme glaciation events on the continent? Under a hypothesis of geothermal glacial refugia and subsequent recolonization of nongeothermal regions, we would expect to find greater contemporary diversity close to geothermal sites than in nongeothermal regions, and significant nestedness by distance of this diversity. We used spatial modeling approaches and the most comprehensive, validated terrestrial biodiversity dataset yet created for Antarctica to assess spatial patterns of diversity on the continent. Models clearly support our hypothesis, indicating that geothermally active regions have played a key role in structuring biodiversity patterns in Antarctica. These results provide critical insights into the evolutionary importance of geothermal refugia and the history of Antarctic species. PMID:24616489

  20. Geopressured-geothermal well activities in Louisiana

    SciTech Connect

    John, C.J.

    1992-10-01

    Since September 1978, microseismic networks have operated continuously around US Department of Energy (DOE) geopressured-geothermal well sites to monitor any microearthquake activity in the well vicinity. Microseismic monitoring is necessary before flow testing at a well site to establish the level of local background seismicity. Once flow testing has begun, well development may affect ground elevations and/or may activate growth faults, which are characteristic of the coastal region of southern Louisiana and southeastern Texas where these geopressured-geothermal wells are located. The microseismic networks are designed to detest small-scale local earthquakes indicative of such fault activation. Even after flow testing has ceased, monitoring continues to assess any microearthquake activity delayed by the time dependence of stress migration within the earth. Current monitoring shows no microseismicity in the geopressured-geothermal prospect areas before, during, or after flow testing.

  1. Fine-grained clay fraction (,0.2 {mu}m): An interesting tool to approach the present thermal and permeability state in active geothermal systems

    SciTech Connect

    Patrier, P.; Papapanagiotou, P.; Beaufort, D.; Traineau, H.; Bril, H.

    1992-01-01

    We have investigated by X-ray diffraction the very fine grained secondary minerals (< 0.2 {micro}m) developed in geothermal systems, in relation with their present thermal and permeability state. Because the smallest particles are the most reactive part of a rock, they are the youngest mineral phases of the geothermal fields. This study has been performed on two active geothermal fields: Milos field, Greece (130 < T < 320 C) and Chipilapa field, Salvador (90 < T < 215 C). In the Milos field, the mineralogical composition of the < 0.2 {micro}m clay fraction observed in the reservoir strongly differs from the overlying altered metamorphic schists in the presence of abundant quantities of saponite and talc/saponite interstratified minerals at unusually high temperature. These phases are considered to be kinetically control-led ''metastable'' minerals which rapidly evolve towards actinolite and talc for present temperatures higher than 300 C. Their occurrence is a good indicator of discharge in highly permeable zones. In the geothermal field of Chipilapa, the mineralogical composition of the < 0.2 {micro}m clay fractions fairly agrees with the temperatures presently measured in the wells, whereas several discrepancies may be pointed out from the compositions of coarser clay fractions (< 5 {micro}m) which contain minerals inherited from higher temperature stages. Permeable zones may be evidenced from an increase of expandable components in the interstratified minerals and a decrease of the coherent domain of the unexpandable clay particles (chlorite).

  2. Towards understanding the puzzling lack of acid geothermal springs in Tibet (China): Insight from a comparison with Yellowstone (USA) and some active volcanic hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Guo, Qinghai; Kirk Nordstrom, D.; Blaine McCleskey, R.

    2014-11-01

    Explanations for the lack of acid geothermal springs in Tibet are inferred from a comprehensive hydrochemical comparison of Tibetan geothermal waters with those discharged from Yellowstone (USA) and two active volcanic areas, Nevado del Ruiz (Colombia) and Miravalles (Costa Rica) where acid springs are widely distributed and diversified in terms of geochemical characteristic and origin. For the hydrothermal areas investigated in this study, there appears to be a relationship between the depths of magma chambers and the occurrence of acid, chloride-rich springs formed via direct magmatic fluid absorption. Nevado del Ruiz and Miravalles with magma at or very close to the surface (less than 1-2 km) exhibit very acidic waters containing HCl and H2SO4. In contrast, the Tibetan hydrothermal systems, represented by Yangbajain, usually have fairly deep-seated magma chambers so that the released acid fluids are much more likely to be fully neutralized during transport to the surface. The absence of steam-heated acid waters in Tibet, however, may be primarily due to the lack of a confining layer (like young impermeable lavas at Yellowstone) to separate geothermal steam from underlying neutral chloride waters and the possible scenario that the deep geothermal fluids below Tibet carry less H2S than those below Yellowstone.

  3. Geopressured-geothermal well activities in Louisiana

    Microsoft Academic Search

    1992-01-01

    Since September 1978, microseismic networks have operated continuously around US Department of Energy (DOE) geopressured-geothermal well sites to monitor any microearthquake activity in the well vicinity. Microseismic monitoring is necessary before flow testing at a well site to establish the level of local background seismicity. Once flow testing has begun, well development may affect ground elevations and\\/or may activate growth

  4. Enhanced Geothermal Systems (EGS) R&D Program, Status Report: Foreign Research on Enhanced Geothermal Systems

    SciTech Connect

    McLarty, Lynn; Entingh, Daniel

    2000-09-29

    This report reviews enhanced geothermal systems (EGS) research outside the United States. The term ''enhanced geothermal systems'' refers to the use of advanced technology to extract heat energy from underground in areas with higher than average heat flow but where the natural permeability or fluid content is limited. EGS covers the spectrum of geothermal resources from low permeability hydrothermal to hot dry rock.

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

    SciTech Connect

    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)

  6. Radionuclide mobility in the shallow portion of an active high-temperature geothermal system

    SciTech Connect

    Sturchio, N.C.; Seitz, M.G.

    1984-01-01

    Accurate knowledge of the behavior of radionuclides in natural rock-water systems is crucial for the prediction of the consequences of failure of a high-level nuclear waste repository. Work in progress at Argonne National Laboratory involves the detailed geochemical analysis of rock, mineral, and water samples from shallow drill holes in a thermal area of Yellowstone National Park. This study is designed to provide data that will increase our understanding of the behavior of a group of radionuclides in an environment similar to that of the near field of a high-level nuclear waste repository.

  7. Seismology and Enhanced Geothermal Systems Bruce R. Julian

    E-print Network

    Foulger, G. R.

    Seismology and Enhanced Geothermal Systems Bruce R. Julian Foulger Consulting, Palo Alto, CA 94306 in geothermal systems, and in Enhanced Geothermal Systems (EGS) experiments in particular, although many failure in both natural and exploited geothermal systems. Differential methods are poor for determining

  8. Enhanced Geothermal Systems (EGS) R&D Program: US Geothermal Resources Review and Needs Assessment

    SciTech Connect

    Entingh, Dan; McLarty, Lynn

    2000-11-30

    The purpose of this report is to lay the groundwork for an emerging process to assess U.S. geothermal resources that might be suitable for development as Enhanced Geothermal Systems (EGS). Interviews of leading geothermists indicate that doing that will be intertwined with updating assessments of U.S. higher-quality hydrothermal resources and reviewing methods for discovering ''hidden'' hydrothermal and EGS resources. The report reviews the history and status of assessment of high-temperature geothermal resources in the United States. Hydrothermal, Enhanced, and Hot Dry Rock resources are addressed. Geopressured geothermal resources are not. There are three main uses of geothermal resource assessments: (1) They inform industry and other interest parties of reasonable estimates of the amounts and likely locations of known and prospective geothermal resources. This provides a basis for private-sector decisions whether or not to enter the geothermal energy business at all, and for where to look for useful resources. (2) They inform government agencies (Federal, State, local) of the same kinds of information. This can inform strategic decisions, such as whether to continue to invest in creating and stimulating a geothermal industry--e.g., through research or financial incentives. And it informs certain agencies, e.g., Department of Interior, about what kinds of tactical operations might be required to support such activities as exploration and leasing. (3) They help the experts who are performing the assessment(s) to clarify their procedures and data, and in turn, provide the other two kinds of users with a more accurate interpretation of what the resulting estimates mean. The process of conducting this assessment brings a spotlight to bear on what has been accomplished in the domain of detecting and understanding reservoirs, in the period since the last major assessment was conducted.

  9. Small geothermal electric systems for remote powering

    SciTech Connect

    Entingh, Daniel J.; Easwaran, Eyob.; McLarty, Lynn

    1994-08-08

    This report describes conditions and costs at which quite small (100 to 1,000 kilowatt) geothermal systems could be used for off-grid powering at remote locations. This is a first step in a larger process of determining locations and conditions at which markets for such systems could be developed. The results suggest that small geothermal systems offer substantial economic and environmental advantages for powering off-grid towns and villages. Geothermal power is most likely to be economic if the system size is 300 kW or greater, down to reservoir temperatures of 100{degree}C. For system sizes smaller than 300 kW, the economics can be favorable if the reservoir temperature is about 120{degree}C or above. Important markets include sites remote from grids in many developing and developed countries. Estimates of geothermal resources in many developing countries are shown.

  10. Geothermal systems ancient and modern: a geochemical review

    Microsoft Academic Search

    R. W. Henley; A. J. Ellis

    1983-01-01

    Geothermal systems occur in a range of crustal settings. The emphasis of this review is on those occurring in regions of active or recently active volcanism, where magmatic heat at depths up to 8 km leads to convection of groundwater in the upper crust. Hot water (and steam) flows are controlled by the permeability of the crust and recent data

  11. Electromagnetic Study of the Grímsvötn Volcanic Geothermal System in Iceland

    NASA Astrophysics Data System (ADS)

    Vilhjalmsson, A. M.; Arnason, K.; Gudmundsson, M. T.

    2010-12-01

    Deep resistivity surveys have greatly improved the understanding of the inner and deep nature of volcanic high-temperature geothermal systems. In this study the Long Offset Transient Electro-Magnetic (LOTEM) method will be used to map the spatial extend and depth span of resistivity anomalies within the Grímsvötn geothermal system, located in the glacier Vatnajökull, SE Iceland. Electromagnetic methods have until now not been used in Grímsvötn, but the first part of a LOTEM survey was carried out during the summer of 2010 to be continued in the summer of 2011. Resistivity methods have the advantage of being highly sensitive to temperature in comparison with other geophysical methods. The application of such methods offers important new information on the nature of the geothermal system and its relation to volcanic intrusions and magma bodies. Grímsvötn is the most active volcano in Iceland in terms of eruption frequency, with over 60 known eruptions in the last 800 years. The study area is mostly covered with 300 - 600 m thick ice. Using the ice as calorimeter the thermal output of the area has been estimated 2000 - 4000 MW, showing that it is one of the most powerful geothermal areas in the world. This unusual situation, where the resistivity structure can be studied and thermal output calculated, gives a unique opportunity to estimate the total thermal output of other high-temperature systems, by resistivity structure comparison. Another objective of the study is to map the location and extent of magma bodies in the uppermost 3 - 5 km of the crust under the volcano and to assess the thermal release from a pristine geothermal system for comparison with other geothermal systems under full exploitation The data will be interpreted by advanced 3D inversion codes. The resulting 3D resistivity model will be interpreted jointly with other existing geophysical data from Grímsvötn, such as gravity and seismic, to make a conceptual model of the Grímsvötn volcano, its high-temperature geothermal system and their inner structure.

  12. Geothermal Progress Monitor: system status and operational experience

    Microsoft Academic Search

    R. E. Gerstein; L. D. Kenkeremath; M. B. Murphy; D. J. Entingh

    1982-01-01

    The Geothermal Progress Monitor (GPM) is an information system designed and implemented by the MITRE Corporation on behalf of the Division of Geothermal and Hydropower Technology (DGHT, formerly Division of Geothermal Energy) of the US Department of Energy (DOE). Its purpose is to keep track of and to report significant events and trends in the US geothermal industry and the

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

    NASA Astrophysics Data System (ADS)

    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 of the collected data with statistical techniques allowed a reliable interpretation and application of the related software. The course starts with a lecture day reviewing on geothermal exploration, introduction into structural geology, geochemistry and applied volcanology (1st day) and continues with practical work in the Tangkuban Perahu volcano field and surrounding area (2nd - 5th days, from morning until late afternoon). The collected field data are processed and analyzed daily after field work. On the last day, each group of participants gives a presentation related to their field and laboratory investigations and to evidence the lessons learned. In particular, the participants learn practical work in field and laboratory, and theoretical data analysis. Sampling and analysis of self-collected data are fundamental for any interpretation and assessment of reservoir potential. The success of the first Geothermal Field Camp 2011 speaks for a continuation and extension of the training program in 2012 and the following years. Future activity will integrate more collaboration partners and will cover a larger diversity of educational topics and geological-geothermal setting.

  14. Geothermal materials development: FY 1990 accomplishments and current activities

    SciTech Connect

    Kukacka, L.E.

    1991-01-01

    Advances in the development of hydrothermally stable materials, the commercial availabilities of which are considered essential for the attainment of the Geothermal Division's (GD) Hydrothermal Category Objectives, continue to be made. Fiscal year 1990 R D was focused on reducing well drilling and completion costs, energy conversion costs, and on mitigating corrosion in well casing. Activities on lost circulation control materials, CO{sub 2}-resistant lightweight cements and thermally conductive corrosion and scale-resistant linear systems have reached the final development stages. In addition, field tests to determine the feasibility for the use of polymer cement liners to mitigate HCl-induced corrosion at the Geysers were performed. Technology transfer efforts on high temperature elastomers for use in drilling tools such as drillpipe protectors and rotating head seals were continued under Geothermal Drilling Organization sponsorship. Recent accomplishments and ongoing work on each of these activities are described in the paper. 8 refs.

  15. Town of Pagosa Springs geothermal heating system

    SciTech Connect

    Garcia, M.B.

    1997-08-01

    The Town of Pagosa Springs has owned and operated a geothermal heating system since December 1982 to provide geothermal heating during the fall, winter and spring to customers in this small mountain town. Pagosa Springs is located in Archuleta County, Colorado in the southwestern corner of the State. The Town, nestled in majestic mountains, including the Continental Divide to the north and east, has an elevation of 7,150 feet. The use of geothermal water in the immediate area, however, dates back to the 1800`s, with the use of Ute Bands and the Navajo Nation and later by the U.S. Calvery in the 1880`s (Lieutenant McCauley, 1878). The Pagosa area geothermal water has been reported to have healing and therapeutic qualities.

  16. Performance of deep geothermal energy systems

    NASA Astrophysics Data System (ADS)

    Manikonda, Nikhil

    Geothermal energy is an important source of clean and renewable energy. This project deals with the study of deep geothermal power plants for the generation of electricity. The design involves the extraction of heat from the Earth and its conversion into electricity. This is performed by allowing fluid deep into the Earth where it gets heated due to the surrounding rock. The fluid gets vaporized and returns to the surface in a heat pipe. Finally, the energy of the fluid is converted into electricity using turbine or organic rankine cycle (ORC). The main feature of the system is the employment of side channels to increase the amount of thermal energy extracted. A finite difference computer model is developed to solve the heat transport equation. The numerical model was employed to evaluate the performance of the design. The major goal was to optimize the output power as a function of parameters such as thermal diffusivity of the rock, depth of the main well, number and length of lateral channels. The sustainable lifetime of the system for a target output power of 2 MW has been calculated for deep geothermal systems with drilling depths of 8000 and 10000 meters, and a financial analysis has been performed to evaluate the economic feasibility of the system for a practical range of geothermal parameters. Results show promising an outlook for deep geothermal systems for practical applications.

  17. Combined Helium and CO2 Isotope Systematics of Turkish Geothermal Systems: Relation to Volcanism and Active Tectonics

    NASA Astrophysics Data System (ADS)

    Gulec, N.; Mutlu, H.; Hilton, D. R.

    2014-12-01

    Helium and CO2 isotope compositions and CO2/3He ratios of Turkish geothermal fluids from various neotectonic provinces suggest genetic relationships with magmatic and tectonic activities. The provinces include western and eastern Anatolia, experiencing extensional and compressional regimes, respectively, and the North Turkish province experiencing strike-slip tectonics associated with the North Anatolian Fault Zone (NAFZ). He-isotope compositions display a range of values from 0.27-1.67 Ra for western Anatolia, 0.85-7.76 Ra for eastern Anatolia, and 0.28-2.19 Ra for NAFZ fluids, with ?13C values between -8.04 and +0.35 ‰, -14.59 and +1.30 ‰ , and -1.92 and +1.52‰ , respectively. CO2/3He ratios lie between 1.66x109-2.35x1013, 2.4x105-3.7x1013and 32x109-26x1013for the fluids of western and eastern Anatolia and the NAFZ, respectively. Combined He-CO2 systematics suggest that degassing and preferential CO2 loss significantly affects some samples resulting in the fractionation of elemental CO2/He ratios.Quantitative assessment of the volatile inventory suggests ~97% and 10% mantle-derived component in the He- and C-inventories, the C-budget being dominated by carbonate contributions in agreement with the composition of basement metamorphics (containing marble) and reservoir lithologies (marble, limestone) in most fields. The highest mantle-He contribution, accompanied by the highest mantle-C, is recorded in eastern Anatolia in the vicinity of the most recently-active Nemrut volcano. Relatively high mantle-He and mantle-C contributions in the Tuzla field of western Anatolia display close spatial association with young, alkaline volcanics. Along the NAFZ, the highest mantle contributions are recorded at the most seismically-active western-central segment. Collectively, these observations suggest the addition of mantle volatiles to crust by young magmatic activities and their transfer to the surface via fault zones of these tectonic provinces.

  18. Power conversion and systems for recovering geothermal heat

    Microsoft Academic Search

    Sheinbaum

    1978-01-01

    A process for the conversion of geothermal heat energy into electrical power by advantageously combining direct and indirect heat exchange systems and other systems to maximize the power production is presented. Specifically, a process and system is presented for the utilization of geothermal heat from flashed geothermal hot fluids composed of hot liquid and vapor. The heat from the hot

  19. A Geothermal GIS for Nevada: Defining Regional Controls and Favorable Exploration Terrains for Extensional Geothermal Systems

    USGS Publications Warehouse

    Coolbaugh, M.F.; Taranik, J.V.; Raines, G.L.; Shevenell, L.A.; Sawatzky, D.L.; Bedell, R.; Minor, T.B.

    2002-01-01

    Spatial analysis with a GIS was used to evaluate geothermal systems in Nevada using digital maps of geology, heat flow, young faults, young volcanism, depth to groundwater, groundwater geochemistry, earthquakes, and gravity. High-temperature (>160??C) extensional geothermal systems are preferentially associated with northeast-striking late Pleistocene and younger faults, caused by crustal extension, which in most of Nevada is currently oriented northwesterly (as measured by GPS). The distribution of sparse young (160??C) geothermal systems in Nevada are more likely to occur in areas where the groundwater table is shallow (<30m). Undiscovered geothermal systems may occur where groundwater levels are deeper and hot springs do not issue at the surface. A logistic regression exploration model was developed for geothermal systems, using young faults, young volcanics, positive gravity anomalies, and earthquakes to predict areas where deeper groundwater tables are most likely to conceal geothermal systems.

  20. Convective heat transport in geothermal systems

    SciTech Connect

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

    1986-08-01

    Most geothermal systems under exploitation for direct use or electrical power production are of the hydrothermal type, where heat is transferred essentially by convection in the reservoir, conduction being secondary. In geothermal systems, buoyancy effects are generally important, but often the fluid and heat flow patterns are largely controlled by geologic features (e.g., faults, fractures, continuity of layers) and location of recharge and discharge zones. During exploitation, these flow patterns can drastically change in response to pressure and temperature declines, and changes in recharge/discharge patterns. Convective circulation models of several geothermal systems, before and after start of fluid production, are described, with emphasis on different characteristics of the systems and the effects of exploitation on their evolution. Convective heat transport in geothermal fields is discussed, taking into consideration (1) major geologic features; (2) temperature-dependent rock and fluid properties; (3) fracture- versus porous-medium characteristics; (4) single- versus two-phase reservoir systems; and (5) the presence of noncondensible gases.

  1. Towards the Understanding of Induced Seismicity in Enhanced Geothermal Systems

    SciTech Connect

    Gritto, Roland; Dreger, Douglas; Heidbach, Oliver; Hutchings, Lawrence

    2014-08-29

    This DOE funded project was a collaborative effort between Array Information Technology (AIT), the University of California at Berkeley (UCB), the Helmholtz Centre Potsdam - German Research Center for Geosciences (GFZ) and the Lawrence Berkeley National Laboratory (LBNL). It was also part of the European research project “GEISER”, an international collaboration with 11 European partners from six countries including universities, research centers and industry, with the goal to address and mitigate the problems associated with induced seismicity in Enhanced Geothermal Systems (EGS). The goal of the current project was to develop a combination of techniques, which evaluate the relationship between enhanced geothermal operations and the induced stress changes and associated earthquakes throughout the reservoir and the surrounding country rock. The project addressed the following questions: how enhanced geothermal activity changes the local and regional stress field; whether these activities can induce medium sized seismicity M > 3; (if so) how these events are correlated to geothermal activity in space and time; what is the largest possible event and strongest ground motion, and hence the potential hazard associated with these activities. The development of appropriate technology to thoroughly investigate and address these questions required a number of datasets to provide the different physical measurements distributed in space and time. Because such a dataset did not yet exist for an EGS system in the United State, we used current and past data from The Geysers geothermal field in northern California, which has been in operation since the 1960s. The research addressed the need to understand the causal mechanisms of induced seismicity, and demonstrated the advantage of imaging the physical properties and temporal changes of the reservoir. The work helped to model the relationship between injection and production and medium sized magnitude events that have jeopardized, and in some cases suspended, the generation of energy from EGS systems worldwide.

  2. Induced seismicity associated with enhanced geothermal system

    SciTech Connect

    Majer, Ernest; Majer, Ernest L.; Baria, Roy; Stark, Mitch; Oates, Stephen; Bommer, Julian; Smith, Bill; Asanuma, Hiroshi

    2006-09-26

    Enhanced Geothermal Systems (EGS) offer the potential to significantly add to the world energy inventory. As with any development of new technology, some aspects of the technology has been accepted by the general public, but some have not yet been accepted and await further clarification before such acceptance is possible. One of the issues associated with EGS is the role of microseismicity during the creation of the underground reservoir and the subsequent extraction of the energy. The primary objectives of this white paper are to present an up-to-date review of the state of knowledge about induced seismicity during the creation and operation of enhanced geothermal systems, and to point out the gaps in knowledge that if addressed will allow an improved understanding of the mechanisms generating the events as well as serve as a basis to develop successful protocols for monitoring and addressing community issues associated with such induced seismicity. The information was collected though literature searches as well as convening three workshops to gather information from a wide audience. Although microseismicity has been associated with the development of production and injection operations in a variety of geothermal regions, there have been no or few adverse physical effects on the operations or on surrounding communities. Still, there is public concern over the possible amount and magnitude of the seismicity associated with current and future EGS operations. It is pointed out that microseismicity has been successfully dealt with in a variety of non-geothermal as well as geothermal environments. Several case histories are also presented to illustrate a variety of technical and public acceptance issues. It is concluded that EGS Induced seismicity need not pose any threat to the development of geothermal resources if community issues are properly handled. In fact, induced seismicity provides benefits because it can be used as a monitoring tool to understand the effectiveness of the EGS operations and shed light on the mechanics of the reservoir.

  3. Induced seismicity associated with enhanced geothermal system

    Microsoft Academic Search

    Ernest Majer; Roy Baria; Mitch Stark; Stephen Oates; Julian Bommer; Bill Smith; Hiroshi Asanuma

    2006-01-01

    Enhanced Geothermal Systems (EGS) offer the potential to significantly add to the world energy inventory. As with any development of new technology, some aspects of the technology has been accepted by the general public, but some have not yet been accepted and await further clarification before such acceptance is possible. One of the issues associated with EGS is the role

  4. Induced seismicity associated with Enhanced Geothermal Systems

    Microsoft Academic Search

    Ernest L. Majer; Roy Baria; Mitch Stark; Stephen Oates; Julian Bommer; Bill Smith; Hiroshi Asanuma

    2007-01-01

    Enhanced Geothermal Systems (EGS) have the potential to make a significant contribution to the world energy inventory. One controversial issue associated with EGS, however, is the impact of induced seismicity or microseismicity, which has been the cause of delays and threatened cancellation of at least two EGS projects worldwide. Although microseismicity has in fact had few (or no) adverse physical

  5. Layered Thermohaline Convection in Hypersaline Geothermal Systems

    Microsoft Academic Search

    Curtis M. Oldenburg; Karsten Pruess

    1998-01-01

    Thermohaline convection occurs in hypersaline geothermal systems due to thermal and salinity effects on liquid density. Because of its importance in oceanography, thermohaline convection in viscous liquids has received more attention than thermohaline convection in porous media. The fingered and layered convection patterns observed in viscous liquid thermohaline convection have been hypothesized to occur also in porous media. However, the

  6. Power producing system employing geothermally heated fluid

    Microsoft Academic Search

    Shields

    1977-01-01

    A power producing system includes a source of geothermally heated fluid having inorganic salts dissolved therein. The fluid is directed through a first direct contact heat exchanger in heat transfer relation with a working fluid of a type insoluble in a liquid including inorganic salts. The vaporous working fluid thus produced is expanded through a prime mover and then directed

  7. ELVIS: Multi-Electrolyte Aqueous Activity Model for Geothermal Solutions

    NASA Astrophysics Data System (ADS)

    Hingerl, F. F.; Wagner, T.; Driesner, T.; Kulik, D. A.; Kosakowski, G.

    2011-12-01

    High temperature, pressure, and fluid salinities render geochemical modeling of fluid-rock interactions in Enhanced Geothermal Systems a demanding task. Accurate prediction of fluid-mineral equilibria strongly depends on the availability of thermodynamic data and activity models. Typically, the Pitzer activity model is applied for geothermal fluids. A drawback of this model is the large number of parameters required to account for temperature and pressure dependencies, which significantly reduces computational efficiency of reactive transport simulations. In addition, most available parameterizations are valid only at vapor-saturated conditions. As an alternative we implemented the EUNIQUAC local composition model [2] that needs substantially fewer fitting parameters. However, the current EUNIQUAC model design does not include provision for high temperature (>150°C) applications and lacks a formulation for pressure dependence. Therefore, its application to geothermal conditions requires a re-formulation and re-fitting of the model. We developed a new tool termed GEMSFIT that allows generic fitting of activity models (for aqueous electrolyte and non-electrolyte solutions) and equations of state implemented in our geochemical equilibrium solver GEM-Selektor (http://gems.web.psi.ch). GEMSFIT combines a PostgreSQL database for storing and managing the datasets of experimental measurements and interaction parameters, the parallelized genetic algorithm toolbox of MATLAB° for the parameter fitting, and an interface to the numerical kernel of GEM-Selektor to access activity models and perform chemical equilibrium calculations. Benchmarking of the partly re-parameterized EUNIQUAC model against Pitzer revealed that the former is less accurate, which can result in incorrect predictions of mineral precipitation/dissolution. Consequently, we modified the EUNIQUAC model and concurrently introduced a pressure dependence to be able to fit experimental data over wide ranges of pressure, temperature, and composition. The new model, called ELVIS, combines an electrostatic framework developed by Helgeson and coworkers [1] with non- electrostatic concepts derived from the EUNIQUAC model [2]. ELVIS has significantly less fitting parameters than the Pitzer approach, but is sufficiently accurate in predicting mineral solubility within experimental error. Results of first parameterizations of ELVIS to geothermal solutions (dilute to concentrated brines from ambient conditions to ~300°C and ~800bars) will be presented. [1] Helgeson, H. H., Kirkham, D. H., Flowers, G. C. (1981), Am. J. Sc. 281, 1249-1516. [2] Thomsen, K., Rasmussen, P., Gani, R. (1996), Chem. Eng. Sc. 51, 3675-3683.

  8. Geothermal

    NSDL National Science Digital Library

    Iowa Public Television. Explore More Project

    2004-01-01

    What part does geothermal energy play in satisfying energy demands? This informational piece, part of a series about the future of energy, introduces students to heat within the Earth as an energy source. Here students read about the uses, benefits, and limitations of geothermal energy. Articles and information on places around the world that use geothermal energy and geothermal use by schools in Iowa are available from a sidebar. A link to a map of geothermal hotspots around the world is provided, along with a link to an ABC News article about geothermal power.

  9. Finite-element solutions for geothermal systems

    NASA Technical Reports Server (NTRS)

    Chen, J. C.; Conel, J. E.

    1977-01-01

    Vector potential and scalar potential are used to formulate the governing equations for a single-component and single-phase geothermal system. By assuming an initial temperature field, the fluid velocity can be determined which, in turn, is used to calculate the convective heat transfer. The energy equation is then solved by considering convected heat as a distributed source. Using the resulting temperature to compute new source terms, the final results are obtained by iterations of the procedure. Finite-element methods are proposed for modeling of realistic geothermal systems; the advantages of such methods are discussed. The developed methodology is then applied to a sample problem. Favorable agreement is obtained by comparisons with a previous study.

  10. A spectral model for shallow geothermal systems

    Microsoft Academic Search

    Rafid Al-Khoury

    2012-01-01

    Purpose – The purpose of this paper is to introduce a spectral model capable of simulating fully transient conductive-convective heat transfer processes in an axially-symmetric shallow geothermal system consisting of a borehole heat exchanger embedded in a soil mass. Design\\/methodology\\/approach – The proposed model combines the exactness of the analytical methods with important extent of generality in describing the geometry

  11. Temporary Cementitious Sealers in Enhanced Geothermal Systems

    SciTech Connect

    Sugama T.; Pyatina, T.; Butcher, T.; Brothers, L.; Bour, D.

    2011-12-31

    Unlike conventional hydrothennal geothermal technology that utilizes hot water as the energy conversion resources tapped from natural hydrothermal reservoir located at {approx}10 km below the ground surface, Enhanced Geothermal System (EGS) must create a hydrothermal reservoir in a hot rock stratum at temperatures {ge}200 C, present in {approx}5 km deep underground by employing hydraulic fracturing. This is the process of initiating and propagating a fracture as well as opening pre-existing fractures in a rock layer. In this operation, a considerable attention is paid to the pre-existing fractures and pressure-generated ones made in the underground foundation during drilling and logging. These fractures in terms of lost circulation zones often cause the wastage of a substantial amount of the circulated water-based drilling fluid or mud. Thus, such lost circulation zones must be plugged by sealing materials, so that the drilling operation can resume and continue. Next, one important consideration is the fact that the sealers must be disintegrated by highly pressured water to reopen the plugged fractures and to promote the propagation of reopened fractures. In response to this need, the objective of this phase I project in FYs 2009-2011 was to develop temporary cementitious fracture sealing materials possessing self-degradable properties generating when {ge} 200 C-heated scalers came in contact with water. At BNL, we formulated two types of non-Portland cementitious systems using inexpensive industrial by-products with pozzolanic properties, such as granulated blast-furnace slag from the steel industries, and fly ashes from coal-combustion power plants. These byproducts were activated by sodium silicate to initiate their pozzolanic reactions, and to create a cemetitious structure. One developed system was sodium silicate alkali-activated slag/Class C fly ash (AASC); the other was sodium silicate alkali-activated slag/Class F fly ash (AASF) as the binder of temper-try sealers. Two specific additives without sodium silicate as alkaline additive were developed in this project: One additive was the sodium carboxymethyl cellulose (CMC) as self-degradation promoting additive; the other was the hard-burned magnesium oxide (MgO) made from calcinating at 1,000-1,500 C as an expansive additive. The AASC and AASF cementitious sealers made by incorporating an appropriate amount of these additives met the following six criteria: 1) One dry mix component product; 2) plastic viscosity, 20 to 70 cp at 300 rpm; 3) maintenance of pumpability for at least 1 hour at 85 C; 4) compressive strength >2000 psi; 5) self-degradable by injection with water at a certain pressure; and 6) expandable and swelling properties; {ge}0.5% of total volume of the sealer.

  12. Active and Fossil Geothermal Activity at Lake Chapala, Mexico

    NASA Astrophysics Data System (ADS)

    Zârate-del Vall, P.

    2002-12-01

    Geothermal systems are very abundant in the tectonically active zones of the earth's crust and the Citala rift, where Lake Chapala is located, is not the exception. The Lake Chapala basin is characterized by its paleo- and actual geothermal activity that includes: thermal springs, fossil sinter deposits and hydrothermal petroleum manifestations. Thermal springs occur both inside and outside the lake. The spring water in out-shore thermal springs around Lake Chapala is carbonate (Medina-Heredia A, 1986). To the NE area is San Luis Agua Caliente (69°C; ~ 240 mg L-1 [HCO3]1) in the NW at Jocotepec (36°C; ~263mg L-1 [HCO3]-); in the South we find Tuxcueca and Tizap n El Alto (30°C; 193 mg L-1 [HCO3]-). However, there is an exception, the spring water at the San Juan Cosal sector (North), which is sulfate (64-83°C; ~479 mg L-1, [SO4]-2). Examples of in-shore thermal springs are "Los Gorgos" (near South shore) and "El Fuerte" (near East shore and temporary "out-shore" because of actual severe drought); the characterisation of water of this in-shore sites is in progress. On the SE shore and five km NW from Regules village, outcrops a carbonate deposit named "La Calera". This carbonate fossil sinter outcrops 2 km in E-W direction and 600 m in N-S direction and overlays andesitic rock. With a thickness of approximately 5m and a roughly horizontal attitude, the carbonated sinter material is characterized by both massive and banded structure. When massive, it is colored in yellow brownish and grey and elsewhere it shows a pseudo-brecciated structure and when banded, alternated of yellow and dark millimetre bands can be seen; is characterized by vuggy porosity and silica (quartz and chalcedony) vein lets. Under microscope a pseudo-micritic texture is observed; vugs coated by iron oxides, are filled with calcite, and/or quartz, chalcedony and clay minerals. Six samples of carbonate of "La Calera" deposit were analysed for their stable isotopes (LODC-UParis VI). From ? 13CPDB values we have two set of data: one near zero (-8.03 to -8.69 \\permil) that means a no contribution of organic carbon and other with low values (-0.35 to -0.75 \\permil) meaning an important contribution of organic carbon; from very low ? 18OPDB values (-8.5 to -0.27 \\permil) we deduced a precipitation in meteoric water with a temperature deposition higher than the surface that matchs with an hydrothermal origin. Mineralogy was confirmed by XRD diffractometry. Near the sub-lacustrine spring "Los Gorgos" there are some small land spots which look like islands (<3-4 m2) made of solid bitumen and which are linked to the bottom of the lake. Because of these hydrocarbon manifestations the company Petróleos Mexicanos drilled (2,348 m deep), without success, an oil exploration well (L¢pez-Ramos, 1979). The characterisation of this solid bitumen is in progress.

  13. Geothermal Systems of the Yellowstone Caldera Field Trip Guide

    SciTech Connect

    Foley, Duncan; Neilson, Dennis L.; Nichols, Clayton R.

    1980-09-08

    Geothermal studies are proceedings on two fronts in the West Yellowstone area. High-temperature resources for the generation of electricity are being sought in the Island Park area, and lower temperatures resources for direct applications, primarily space heating, are being explored for near the town of West Yellowstone. Potential electric geothermal development in the Island Park area has been the subject of widespread publicity over fears of damage to thermal features in Yellowstone Park. At the time of writing this guide, companies have applied for geothermal leases in the Island Park area, but these leases have not yet been granted by the US Forest Service. The Senate is now discussing a bill that would regulate geothermal development in Island Park; outcome of this debate will determine the course of action on the lease applications. The Island Park area was the site of two cycles of caldera activity, with major eruptions at 2.0 and 1.2 million years ago. The US Geological Survey estimates that 16,850 x 10{sup 18} joules of energy may remain in the system. Geothermal resources suitable for direct applications are being sought in the West Yellowstone vicinity by the Montana Bureau of Mines and Geology, under funding from the US Department of Energy. West Yellowstone has a mean annual temperature of 1-2 C. Research thus far suggests that basement rocks in the vicinity are at a depth of about 600 m and are probably similar to the rocks exposed north of Hebgen Lake, where Precambrian, Paleozoic and Mesozoic rocks have been mapped. A few sites with anomalously warm water have been identified near the town. Work is continuing on this project.

  14. National Geothermal Data System: Transforming the Discovery, Access, and Analytics of Data for Geothermal Exploration

    SciTech Connect

    Patten, Kim [Arizona Geological Survey

    2013-05-01

    Compendium of Papers from the 38th Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California February 11-13, 2013 The National Geothermal Data System (NGDS) is a distributed, interoperable network of data collected from state geological surveys across all fifty states and the nation’s leading academic geothermal centers. The system serves as a platform for sharing consistent, reliable, geothermal-relevant technical data with users of all types, while supplying tools relevant for their work. As aggregated data supports new scientific findings, this content-rich linked data ultimately broadens the pool of knowledge available to promote discovery and development of commercial-scale geothermal energy production. Most of the up-front risks associated with geothermal development stem from exploration and characterization of subsurface resources. Wider access to distributed data will, therefore, result in lower costs for geothermal development. NGDS is on track to become fully operational by 2014 and will provide a platform for custom applications for accessing geothermal relevant data in the U.S. and abroad. It is being built on the U.S. Geoscience Information Network (USGIN) data integration framework to promote interoperability across the Earth sciences community. The basic structure of the NGDS employs state-of-the art informatics to advance geothermal knowledge. The following four papers comprising this Open-File Report are a compendium of presentations, from the 38th Annual Workshop on Geothermal Reservoir Engineering, taking place February 11-13, 2013 at Stanford University, Stanford, California. “NGDS Geothermal Data Domain: Assessment of Geothermal Community Data Needs,” outlines the efforts of a set of nationwide data providers to supply data for the NGDS. In particular, data acquisition, delivery, and methodology are discussed. The paper addresses the various types of data and metadata required and why simple links to existing data are insufficient for promoting geothermal exploration. Authors of this paper are Arlene Anderson, US DOE Geothermal Technologies Office, David Blackwell, Southern Methodist University (SMU), Cathy Chickering (SMU), Toni Boyd, Oregon Institute of Technology’s GeoHeat Center, Roland Horne, Stanford University, Matthew MacKenzie, Uberity, Joe Moore, University of Utah, Duane Nickull, Uberity, Stephen Richard, Arizona Geological Survey, and Lisa Shevenell, University of Nevada, Reno. “NGDS User Centered Design: Meeting the Needs of the Geothermal Community,” discusses the user- centered design approach taken in the development of a user interface solution for the NGDS. The development process is research based, highly collaborative, and incorporates state-of-the-art practices to ensure a quality user interface for the widest and greatest utility. Authors of this paper are Harold Blackman, Boise State University, Suzanne Boyd, Anthro-Tech, Kim Patten, Arizona Geological Survey, and Sam Zheng, Siemens Corporate Research. “Fueling Innovation and Adoption by Sharing Data on the DOE Geothermal Data Repository Node on the National Geothermal Data System,” describes the motivation behind the development of the Geothermal Data Repository (GDR) and its role in the NGDS. This includes the benefits of using the GDR to share geothermal data of all types and DOE’s data submission process. Authors of this paper are Jon Weers, National Renewable Energy Laboratory and Arlene Anderson, US DOE Geothermal Technologies Office. Finally, “Developing the NGDS Adoption of CKAN for Domestic & International Data Deployment,” provides an overview of the “Node-In-A-Box” software package designed to provide data consumers with a highly functional interface to access the system, and to ease the burden on data providers who wish to publish data in the system. It is important to note that this software package constitutes a reference implementation and that the NGDS architecture is based on open standards, which means other server software can make resources available, a

  15. Mantle helium and carbon isotopes in Separation Creek Geothermal Springs, Three Sisters area, Central Oregon: Evidence for renewed volcanic activity or a long term steady state system?

    SciTech Connect

    van Soest, M.C.; Kennedy, B.M.; Evans, W.C.; Mariner, R.H.

    2002-04-30

    Cold bubbling springs in the Separation Creek area, the locus of current uplift at South Sister volcano show strong mantle signatures in helium and carbon isotopes and CO{sub 2}/{sup 3}He. This suggests the presence of fresh basaltic magma in the volcanic plumbing system. Currently there is no evidence to link this system directly to the uplift, which started in 1998. To the contrary, all geochemical evidence suggests that there is a long-lived geothermal system in the Separation Creek area, which has not significantly changed since the early 1990s. There was no archived helium and carbon data, so a definite conclusion regarding the strong mantle signature observed in these tracers cannot yet be drawn. There is a distinct discrepancy between the yearly magma supply required to explain the current uplift (0.006 km{sup 3}/yr) and that required to explain the discharge of CO{sub 2} from the system (0.0005 km{sup 3}/yr). This discrepancy may imply that the chemical signal associated with the increase in magma supply has not reached the surface yet. With respect to this the small changes observed at upper Mesa Creek require further attention, due to the recent volcanic vent in that area it may be the location were the chemical signal related to the uplift can most quickly reach the surface. Occurrence of such strong mantle signals in cold/diffuse geothermal systems suggests that these systems should not be ignored during volcano monitoring or geothermal evaluation studies. Although the surface-expression of these springs in terms of heat is minimal, the chemistry carries important information concerning the size and nature of the underlying high-temperature system and any changes taking place in it.

  16. GEOTHERMAL ENVIRONMENTAL IMPACT ASSESSMENT: SUBSURFACE ENVIRONMENTAL ASSESSMENT FOR FOUR GEOTHERMAL SYSTEMS

    EPA Science Inventory

    This is the second in a series of reports concerning the environmental assessments of effluent extraction, energy conversion, and waste disposal in geothermal systems. This study involves the subsurface environmental impact of the Imperial Valley and The Geysers, California; Klam...

  17. Choosing a Geothermal as an HVAC System.

    ERIC Educational Resources Information Center

    Lensenbigler, John D.

    2002-01-01

    Describes the process of selecting and installing geothermal water source heat pumps for new residence halls at Johnson Bible College in Knoxville, Tennessee, including choosing the type of geothermal design, contractors, and interior equipment, and cost and payback. (EV)

  18. Geothermal activity at depth and distribution of deposits of hydrocarbons

    SciTech Connect

    Erofeev, V.F.

    1983-01-01

    The observed regularities in the distribution of the deposits of hydrocarbons reflect the influence of a whole complex of factors; one of the principal ones is the temperature in the interior of the earth. Because deposits of oil and gas are formed under specific thermodynamic conditions, both changes in the physiochemical properties and the phase compositions of the fluids occurring in the depths of the earth will depend on the geothermal activity of the interior. This paper discusses the zonation of hydrocarbons within the Russian Platform and the interpretation of the geologic history, thermodynamic properties, and geothermal activity associated with the formation of these deposits.

  19. National Geothermal Data System: A Geothermal Data System for Exploration and Development

    SciTech Connect

    Allison, Lee [Executive Office of the State of Arizona (Arizona Geological Survey); Richard, Stephen [Executive Office of the State of Arizona (Arizona Geological Survey); Patten, Kim [Executive Office of the State of Arizona (Arizona Geological Survey); Love, Diane [Executive Office of the State of Arizona (Arizona Geological Survey); Coleman, Celia [Executive Office of the State of Arizona (Arizona Geological Survey); Chen, Genhan [Executive Office of the State of Arizona (Arizona Geological Survey)

    2012-09-30

    Geothermal-relevant geosciences data from all 50 states (www.stategeothermaldata.org), federal agencies, national labs, and academic centers are being digitized and linked in a distributed online network funded by the U.S. Department of Energy Geothermal Data System (GDS) to foster geothermal energy exploration and development through use of interactive online ‘mashups,’data integration, and applications. Emphasis is first to make as much information as possible accessible online, with a long range goal to make data interoperable through standardized services and interchange formats. A growing set of more than thirty geoscience data content models is in use or under development to define standardized interchange formats for: aqueous chemistry, borehole temperature data, direct use feature, drill stem test, seismic event hypocenter, fault feature, geologic contact feature, geologic unit feature, thermal/hot spring description, metadata, quaternary fault, volcanic vent description, well header feature, borehole lithology log, crustal stress, gravity, heat flow/temperature gradient, permeability, and feature description data like developed geothermal systems, geologic unit geothermal characterization, permeability, production data, rock alteration description, rock chemistry, and thermal conductivity. Map services are also being developed for isopach maps, aquifer temperature maps, and several states are working on geothermal resource overview maps. Content models are developed based on existing community datasets to encourage widespread adoption and promulgate content quality standards. Geoscience data and maps from other GDS participating institutions, or “nodes” (e.g., U.S. Geological Survey, Southern Methodist University, Oregon Institute of Technology, Stanford University, the University of Utah) are being supplemented with extensive land management and land use resources from the Western Regional Partnership (15 federal agencies and 5 Western states) to provide access to a comprehensive, holistic set of data critical to geothermal energy development. As of May 2012 , we have nearly 37,000 records registered in the system catalog, and 550,075 data resources online, along with hundreds of Web services to deliver integrated data to the desktop for free downloading or online use. The data exchange mechanism is built on the U.S. Geoscience Information Network (USGIN, http://usgin.org and http://lab.usgin.org) protocols and standards developed as a partnership of the Association of American State Geologists (AASG) and U.S. Geological Survey (USGS). Keywords Data

  20. Roosevelt Hot Springs geothermal system, Utah - case study

    Microsoft Academic Search

    H. P. Ross; D. L. Nielson; J. N. Moore

    1982-01-01

    The Roosevelt Hot Springs geothermal system has been undergoing intensive exploration since 1974 and has been used as a natural laboratory for the development and testing of geothermal exploration methods by research organizations. This paper summarizes the geological, geophysical, and geochemistry data which have been collected since 1974, and presents a retrospective strategy describing the most effective means of exploration

  1. Enhanced Geothermal Systems (EGS) R&D Program

    Microsoft Academic Search

    Entingh; Daniel J

    1999-01-01

    The purpose of this workshop was to develop technical background facts necessary for planning continued research and development of Enhanced Geothermal Systems (EGS). EGS are geothermal reservoirs that require improvement of their permeability or fluid contents in order to achieve economic energy production. The initial focus of this R&D program is devising and testing means to extract additional economic energy

  2. Recent Development of HFR Geothermal Reservoir System in Australia

    Microsoft Academic Search

    H. Xing; D. Wyborn; H. Xu; C. Yin; P. Mora

    2006-01-01

    Since the 1970's, a number of research programmes have worked towards developing Hot Dry Rock technology (HDR) for geothermal energy which has been renamed as Hot Fractured Rock (HFR) in Australia. The HFR energy resource has the potential to supply base-load power with no greenhouse gas emissions. This paper will introduce the recent development of HFR geothermal reservoir system in

  3. Application of direct contact heat exchangers in geothermal systems

    Microsoft Academic Search

    I. Oliker

    1977-01-01

    Two applications of direct-contact heat exchangers (DCHs) used in geothermal systems are examined. The first type of DCH is applied to a binary cycle where a secondary fluid is vaporized in contact with the brine (direct contact evaporator). The second type of DCH is applied to a geothermal power plant operating on water vapor only (direct contact condenser); in this

  4. 3D characterization of a Great Basin geothermal system: Astor Pass, NV

    NASA Astrophysics Data System (ADS)

    Siler, D. L.; Mayhew, B.; Faulds, J. E.

    2012-12-01

    The Great Basin exhibits both anomalously high heat flow (~75±5 mWm-2) and active faulting and extension resulting in robust geothermal activity. There are ~430 known geothermal systems in the Great Basin, with evidence suggesting that undiscovered blind geothermal systems may actually represent the majority of geothermal activity. These systems employ discrete fault intersection/interaction areas as conduits for geothermal circulation. Recent studies show that steeply dipping normal faults with step-overs, fault intersections, accommodation zones, horse-tailing fault terminations and transtensional pull-aparts are the most prominent structural controls of Great Basin geothermal systems. These fault geometries produce sub-vertical zones of high fault and fracture density that act as fluid flow conduits. Structurally controlled fluid flow conduits are further enhanced when critically stressed with respect to the ambient stress conditions. The Astor Pass blind geothermal system, northwestern Nevada, lies along the boundary between the Basin and Range to the east and the Walker Lane to the west. Along this boundary, strain is transferred from dextral shear in the Walker Lane to west-northwest directed extension in the Basin and Range. As such, the Astor Pass area lies in a transtensional setting consisting of both northwest-striking, left-stepping dextral faults and more northerly striking normal faults. The Astor Pass tufa tower implies the presence of a blind geothermal system. Previous studies suggest that deposition of the Astor Pass tufa was controlled by the intersection of a northwest-striking dextral normal fault and north-northwest striking normal fault. Subsequent drilling (to ~1200 m) has revealed fluid temperatures of ~94°C, confirming the presence of a blind geothermal system at Astor Pass. Expanding upon previous work and employing additional detailed geologic mapping, interpretation of 2D seismic reflection data and analysis of well cuttings, a 3-dimensional geologic model of the Astor Pass blind geothermal system was constructed. The 3D structural framework indicates that the Pleistocene tufa is associated with three discrete fault zones whose intersections plunge moderately to steeply NW-NNW. These critically stressed fault intersections act as conduits for upwelling geothermal fluids.

  5. Design, construction and evaluation of a simulated geothermal flow system

    SciTech Connect

    Mackanic, J.C.

    1980-07-28

    A system was designed and built to simulate the flow from a geothermal well. The simulated flow will be used to power a Lysholm engine, the performance of which will then be evaluated for different simulated geothermal flows. Two main subjects are covered: 1) the design, construction and evaluation of the behavior of the system that simulates the geothermal flow; included in that topic is a discussion of the probable behavior of the Lysholm engine when it is put into operation, and 2) the investigation of the use of dynamic modeling techniques to determine whether they can provide a suitable means for predicting the behavior of the system.

  6. Geology of the Rotorua geothermal system

    SciTech Connect

    Wood, C.P. (DSIR Geology and Geophysics, Rotorua (NZ))

    1992-04-01

    This paper discusses the Rotorua geothermal system located in the south part of Rotorua Caldera, which collapsed during and after the eruption of Mamaku Ignimbrite some 140 ka ago. Drillholes provide geological and hydrological information to 300 m depth. The Mamaku Ignimbrite aquifer has been drilled in the east and south of the field where it contains fluid at or near boiling point. The Ignimbrite drops from south to north across exposed and buried caldera collapse scarps. Rotorua City domes comprise a buried N-S ridge rising at either end to form north and south domes; both contain mostly sub-boiling water up to 190{degrees} C which flows laterally through the outer 40 m of permeably rhyolite as indicated by temperature data. The Fenton Park aquifer comprises sands and gravels in the shallow sedimentary sequence which contain hot water derived possibly from Whakarewarewa, the south dome or the Rotoatamaheke Fault.

  7. Geothermics 35 (2006) 368408 Tectonic and magmatic evolution of the active

    E-print Network

    Doglioni, Carlo

    2006-01-01

    Geothermics 35 (2006) 368­408 Tectonic and magmatic evolution of the active volcanic front in El Salvador: insight into the Berl´in and Ahuachap´an geothermal areas Samuele Agostinia,, Giacomo Cortia products, at least during the Plio-Quaternary. Detailed analyses within the geothermal fields of Berl

  8. Heat pump assisted geothermal heating system for Felix Spa, Romania

    SciTech Connect

    Rosca, Marcel; Maghiar, Teodor

    1996-01-24

    The paper presents a pre-feasibility type study of a proposed heat pump assisted geothermal heating system for an average hotel in Felix Spa, Romania. After a brief presentation of the geothermal reservoir, the paper gives the methodology and the results of the technical and economical calculations. The technical and economical viability of the proposed system is discussed in detail in the final part of the paper.

  9. Changes in thermal activity in the Rotorua geothermal field

    SciTech Connect

    Cody, A.D. (DSIR Geology and Geophysics, P.O. Box 499, Rotorua (NZ)); Lumb, J.T. (DSIR Geology and Geophysics, P.O. Box 1320, Wellington (NZ))

    1992-04-01

    During a period when geothermal fluid was being withdrawn for energy use at an increasing rate, the level of natural hydrothermal activity in the Rotorua geothermal field declined in an all-time low in the mid 1980s. total heatflow from a major hot-spring area fell by almost 50 percent, springs ceased their flow, and geysers displayed abnormal behavior consistent with a low aquifer pressure. since the enforced closure of bores within 1.5 km of Pohutu Geyser, sings of recovery, including a return to normal behavior of Pohutu and Waikorohihi Geysers, a resumption of activity at Kereru Geyser, and an increase in water flow from some springs are presented in this paper.

  10. Magnetotelluric imaging of the Reporoa geothermal system in New Zealand

    NASA Astrophysics Data System (ADS)

    Walter, Christina; Jones, Alan G.; Ryan, Graham A.

    2013-04-01

    The Reporoa geothermal area is located in a caldera on the eastern side of the Taupo Volcanic Zone in the North Island of New Zealand. For the last 40 years scientists have argued whether Reporoa is an independent geothermal system or just an outflow structure of the Waiotapu geothermal system to the north. Due to its location and possible connection to the Waiotapu geothermal system, which is a protected system and a big tourist attraction, the Reporoa system needs to be well characterised before commercial exploitation can be considered. Early DC resistivity surveys yielded information to depths of about 1 km, but were unable to resolve which, if either, of the two competing models was correct. In this project we electrically image much deeper structures beneath the Reporoa geothermal area in order to understand better this system. MT is a passive geophysical exploration tool that utilises naturally-occurring, time-varying electromagnetic (EM) fields recorded on the surface to determine spatial variations in subsurface electrical resistivity. Temperature, porosity and fluid content, as well as hydrothermal alteration processes, have significant effects on patterns of subsurface electrical resistivity. Therefore, MT is well suited to image the different parts of a geothermal system, and is accordingly the most utilized geophysical imaging technique in geothermal research. For this study close to 100 broadband Magnetotelluric (MT) measurements, acquired during several separate surveys over a 3 year period, were analysed and modelled. Station spacing varied from 500 m to 2 km forming a grid over the study area. The maximum depth of investigation for this study, which is a function of the subsurface resistivity and the maximum period of measurement (100 s), is of the order of several kilometres. This paper will describe the data acquired and models derived. Preliminary results from this study indicate both an outflow structure from Waiotapu at shallow depths and an independent geothermal upflow at depth.

  11. Enhanced Geothermal Systems (EGS) R&D Program

    SciTech Connect

    Entingh, Daniel J.

    1999-08-18

    The purpose of this workshop was to develop technical background facts necessary for planning continued research and development of Enhanced Geothermal Systems (EGS). EGS are geothermal reservoirs that require improvement of their permeability or fluid contents in order to achieve economic energy production. The initial focus of this R&D program is devising and testing means to extract additional economic energy from marginal volumes of hydrothermal reservoirs that are already producing commercial energy. By mid-1999, the evolution of the EGS R&D Program, begun in FY 1988 by the U.S. Department of Energy (DOE), reached the stage where considerable expertise had to be brought to bear on what technical goals should be pursued. The main purpose of this Workshop was to do that. The Workshop was sponsored by the Office of Geothermal Technologies of the Department of Energy. Its purpose and timing were endorsed by the EGS National Coordinating Committee, through which the EGS R&D Program receives guidance from members of the U.S. geothermal industry. Section 1.0 of this report documents the EGS R&D Program Review Session. There, managers and researchers described the goals and activities of the program. Recent experience with injection at The Geysers and analysis of downhole conditions at Dixie Valley highlighted this session. Section 2.0 contains a number of technical presentations that were invited or volunteered to illuminate important technical and economic facts and opportunities for research. The emphasis here was on fi.acture creation, detection, and analysis. Section 3.0 documents the initial general discussions of the participants. Important topics that emerged were: Specificity of defined projects, Optimizing cost effectiveness, Main technical areas to work on, Overlaps between EGS and Reservoir Technology R&D areas, Relationship of microseismic events to hydraulic fractures, and Defining criteria for prioritizing research thrusts. Sections 4.0 and 5.0 report the meat of the Workshop. Section 4.0 describes the nomination and clarification of technical thrusts, and Section 5.0 reports the results of prioritizing those thrusts via voting by the participants. Section 6.0 contains two discussions conducted after the work on research thrusts. The topics were ''Simulation'' and ''Stimulation''. A number of technical points that emerged here provide important guidance for both practical field work on EGS systems and for research.

  12. Documentation of the status of international geothermal power plants and a list by country of selected geothermally active governmental and private sector entities

    SciTech Connect

    Not Available

    1992-10-01

    This report includes the printouts from the International Geothermal Power Plant Data Base and the Geothermally Active Entity Data Base. Also included are the explanation of the abbreviations used in the power plant data base, maps of geothermal installations by country, and data base questionnaires and mailing lists.

  13. Geothermal direct applications hardware systems development and testing. 1979 summary report

    SciTech Connect

    Keller, J.G.

    1980-03-01

    Activities performed during calendar year 1979 for the hardware system development and testing task are presented. The fluidized bed technology was applied to the drying of potato by-products and to the exchange of heat to air in the space heating experiment. Geothermal water was flashed to steam and also used as the prime energy source in the steam distillation of peppermint oil. Geothermal water temperatures as low as 112.8/sup 0/C were utilized to distill alcohol from sugar beet juice, and lower temperature water provided air conditioning through an absorption air conditioning system. These experiments are discussed.

  14. Three dimensional images of geothermal systems: local earthquake P-wave velocity tomography at the Hengill and Krafla geothermal areas, Iceland, and The Geysers, California

    USGS Publications Warehouse

    Julian, B.R.; Prisk, A.; Foulger, G.R.; Evans, J.R.

    1993-01-01

    Local earthquake tomography - the use of earthquake signals to form a 3-dimensional structural image - is now a mature geophysical analysis method, particularly suited to the study of geothermal reservoirs, which are often seismically active and severely laterally inhomogeneous. Studies have been conducted of the Hengill (Iceland), Krafla (Iceland) and The Geysers (California) geothermal areas. All three systems are exploited for electricity and/or heat production, and all are highly seismically active. Tomographic studies of volumes a few km in dimension were conducted for each area using the method of Thurber (1983).

  15. [Geothermal system temperature-depth database and model for data analysis]. 5. quarterly technical progress report

    SciTech Connect

    Blackwell, D.D.

    1998-04-25

    During this first quarter of the second year of the contract activity has involved several different tasks. The author has continued to work on three tasks most intensively during this quarter: the task of implementing the data base for geothermal system temperature-depth, the maintenance of the WWW site with the heat flow and gradient data base, and finally the development of a modeling capability for analysis of the geothermal system exploration data. The author has completed the task of developing a data base template for geothermal system temperature-depth data that can be used in conjunction with the regional data base that he had already developed and is now implementing it. Progress is described.

  16. The Newcastle geothermal system, Iron County, Utah

    SciTech Connect

    Blackett, R.E.; Shubat, M.A.; Bishop, C.E. (Utah Geological and Mineral Survey, Salt Lake City, UT (USA)); Chapman, D.S.; Forster, C.B.; Schlinger, C.M. (Utah Univ., Salt Lake City, UT (USA). Dept. of Geology and Geophysics)

    1990-03-01

    Geological, geophysical and geochemical studies contributed to conceptual hydrologic model of the blind'' (no surface expression), moderate-temperature (greater than 130{degree}C) Newcastle geothermal system, located in the Basin and Range-Colorado Plateau transition zone of southwestern Utah. Temperature gradient measurements define a thermal anomaly centered near the surface trace of the range-bounding Antelope Range fault with and elongate dissipative plume extending north into the adjacent Escalante Valley. Spontaneous potential and resistivity surveys sharply define the geometry of the dominant upflow zone (not yet explored), indicating that most of the thermal fluid issues form a short segment along the Antelope Range fault and discharges into a gently-dipping aquifer. Production wells show that this aquifer lies at a depth between 85 and 95 meter. Electrical surveys also show that some leakage of thermal fluid occurs over a 1.5 km (minimum) interval along the trace of the Antelope Range fault. Major element, oxygen and hydrogen isotopic analyses of water samples indicate that the thermal fluid is a mixture of meteoric water derived from recharge areas in the Pine Valley Mountains and cold, shallow groundwater. A northwest-southeast trending system of faults, encompassing a zone of increased fracture permeability, collects meteoric water from the recharge area, allows circulation to a depth of 3 to 5 kilometers, and intersects the northeast-striking Antelope Range fault. We postulate that mineral precipitates form a seal along the Antelope Range fault, preventing the discharge of thermal fluids into basin-fill sediments at depth, and allowing heated fluid to approach the surface. Eventually, continued mineral deposition could result in the development of hot springs at the ground surface.

  17. Standard Guide for Specifying Thermal Performance of Geothermal Power Systems

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This guide covers power plant performance terms and criteria for use in evaluation and comparison of geothermal energy conversion and power generation systems. The special nature of these geothermal systems makes performance criteria commonly used to evaluate conventional fossil fuel-fired systems of limited value. This guide identifies the limitations of the less useful criteria and defines an equitable basis for measuring the quality of differing thermal cycles and plant equipment for geothermal resources. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  18. Structural compartmentalisation of a geothermal system, the Torre Alfina field (central Italy)

    NASA Astrophysics Data System (ADS)

    Vignaroli, Gianluca; Pinton, Annamaria; De Benedetti, Arnaldo A.; Giordano, Guido; Rossetti, Federico; Soligo, Michele; Berardi, Gabriele

    2013-11-01

    Recent surging of renewed industrial interest in the exploration of low and medium enthalpy geothermal fields makes the accurate assessment of the geothermal potential essential to minimise uncertainties during both exploration and exploitation. The Torre Alfina field is a case of abandoned, but promising, geothermal field of central Italy where the roles of the internal structural setting and of the recharge areas on the hydrothermal circulation are largely unconstrained. In this paper, field structural data integrated with geomorphic lineament analysis document the occurrence of post-orogenic deformation structures controlling the compartmentalisation of the Torre Alfina geothermal field. Strike-slip and subordinate normal fault systems (with associated network fractures) cut and dislocate the internal architecture of the reservoir and prevent its hydraulic connection with Mount Cetona, considered to be the recharge area and where hydrothermal manifestation, including travertine deposition, occurs. 230Th/234U radiometric dating of superposed travertine units gives 200, 120 and 90 ka respectively, inferred to correspond to the age of the fossil hydrothermal circulation during tectonic activity. The results have been used for illustrating a new geological conceptual model for the Torre Alfina area where the geothermal system is composed of different compartments. Tectonic structures define the main boundaries between compartments, helping the understanding of why productive and non-productive wells were found in apparently similar structural settings within the Torre Alfina field.

  19. A market survey of geothermal wellhead power generation systems

    NASA Technical Reports Server (NTRS)

    Leeds, M. W.

    1978-01-01

    The market potential for a portable geothermal wellhead power conversion device is assessed. Major study objectives included identifying the most promising applications for such a system, the potential impediments confronting their industrialization, and the various government actions needed to overcome these impediments. The heart of the study was a series of structured interviews with key decision-making individual in the various disciplines of the geothermal community. In addition, some technical and economic analyses of a candidate system were performed to support the feasibility of the basic concept.

  20. Progress Toward an Advanced Geothermal Deep-Drilling System

    SciTech Connect

    Rowley, J.; Saito, S.; Long, R.

    1995-01-01

    A previously developed concept for an advanced geothermal drilling system (AGDS) has been extended toward a feasibility design stage. Hardware projects for two percussion, air and hydraulic, hammer drills are underway. Two drill string options and an unique nitrogen supply system are described.

  1. Recommendations of the workshop on advanced geothermal drilling systems

    SciTech Connect

    Glowka, D.A.

    1997-12-01

    At the request of the U.S. Department of Energy, Office of Geothermal Technologies, Sandia National Laboratories convened a group of drilling experts in Berkeley, CA, on April 15-16, 1997, to discuss advanced geothermal drilling systems. The objective of the workshop was to develop one or more conceptual designs for an advanced geothermal drilling system that meets all of the criteria necessary to drill a model geothermal well. The drilling process was divided into ten essential functions. Each function was examined, and discussions were held on the conventional methods used to accomplish each function and the problems commonly encountered. Alternative methods of performing each function were then listed and evaluated by the group. Alternative methods considered feasible or at least worth further investigation were identified, while methods considered impractical or not potentially cost-saving were eliminated from further discussion. This report summarizes the recommendations of the workshop participants. For each of the ten functions, the conventional methods, common problems, and recommended alternative technologies and methods are listed. Each recommended alternative is discussed, and a description is given of the process by which this information will be used by the U.S. DOE to develop an advanced geothermal drilling research program.

  2. Conductive thermal modeling of Wyoming geothermal systems

    SciTech Connect

    Heasler, H.P.; Ruscetta, C.A.; Foley, D. (eds.)

    1981-05-01

    A summary of techniques used by the Wyoming Geothermal Resource Assessment Group in defining low-temperature hydrothermal resource areas is presented. Emphasis is placed on thermal modeling techniques appropriate to Wyoming's geologic setting. Thermal parameters discussed include oil-well bottom hole temperatures, heat flow, thermal conductivity, and measured temperature-depth profiles. Examples of the use of these techniques are from the regional study of the Bighorn Basin and two site specific studies within the Basin.

  3. Modeling and analysis of hybrid geothermal-solar thermal energy conversion systems

    E-print Network

    Greenhut, Andrew David

    2010-01-01

    Innovative solar-geothermal hybrid energy conversion systems were developed for low enthalpy geothermal resources augmented with solar energy. The goal is to find cost-effective hybrid power cycles that take advantage of ...

  4. Dual-temperature Kalina cycle for geothermal-solar hybrid power systems

    E-print Network

    Boghossian, John G

    2011-01-01

    This thesis analyzes the thermodynamics of a power system coupling two renewable heat sources: low-temperature geothermal and a high-temperature solar. The process, referred to as a dual-temperature geothermal-solar Kalina ...

  5. Characterisation of the Basel 1 enhanced geothermal system

    Microsoft Academic Search

    Markus O. Häring; Ulrich Schanz; Florentin Ladner; Ben C. Dyer

    2008-01-01

    This paper describes the steps that have been undertaken to create an enhanced geothermal system (EGS) at the Deep Heat Mining Project in Basel, Switzerland. Preliminary results from drilling, logging, hydraulic testing and stimulating the Basel 1 well are summarized. The project was suspended following the occurrence of several ‘felt’ microseismic events. Because such events may be an inherent risk

  6. Layered Thermohaline Convection in Hypersaline GeothermalSystems

    Microsoft Academic Search

    Curtis M. Oldenburg; Karsten Pruess

    1997-01-01

    Thermohaline convection occurs in hypersaline geothermal systems due to thermal and salinity effects on liquid density. Because of its importance in oceanography, thermohaline convection in viscous liquids has received more attention than thermohaline convection in porous media. The fingered and layered convection patterns observed in viscous liquid thermohaline convection have been hypothesized to occur also in porous media. However, the

  7. Summary of geothermal exploration activity in the State of Washington from 1978 to 1983. Final report

    Microsoft Academic Search

    Korosec

    1984-01-01

    Project activity is summarized with references to the publications produced. Project findings are reported as they relate to specific geothermal resource target areas. Some major projects of the goethermal exploration program are: thermal and mineral spring chemistry, heat flow drilling, temperature gradient measurements, Cascade Range regional gravity, geohydrology study of the Yakima area, low temperature geothermal resources, geology, geochemistry of

  8. Energy Return On Investment of Engineered Geothermal Systems Data

    SciTech Connect

    Mansure, Chip

    2012-01-01

    The project provides an updated Energy Return on Investment (EROI) for Enhanced Geothermal Systems (EGS). Results incorporate Argonne National Laboratory's Life Cycle Assessment and base case assumptions consistent with other projects in the Analysis subprogram. EROI is a ratio of the energy delivered to the consumer to the energy consumed to build, operate, and decommission the facility. EROI is important in assessing the viability of energy alternatives. Currently EROI analyses of geothermal energy are either out-of-date, of uncertain methodology, or presented online with little supporting documentation. This data set is a collection of files documenting data used to calculate the Energy Return On Investment (EROI) of Engineered Geothermal Systems (EGS) and erratum to publications prior to the final report. Final report is available from the OSTI web site (http://www.osti.gov/geothermal/). Data in this collections includes the well designs used, input parameters for GETEM, a discussion of the energy needed to haul materials to the drill site, the baseline mud program, and a summary of the energy needed to drill each of the well designs. EROI is the ratio of the energy delivered to the customer to the energy consumed to construct, operate, and decommission the facility. Whereas efficiency is the ratio of the energy delivered to the customer to the energy extracted from the reservoir.

  9. Structural Orientations Adjacent to Some Colorado Geothermal Systems

    SciTech Connect

    Richard,

    2012-02-01

    Citation Information: Originator: Geothermal Development Associates, Reno, Nevada Publication Date: 2012 Title: Structural Data Edition: First Publication Information: Publication Place: Reno Nevada Publisher: Geothermal Development Associates, Reno, Nevada Description: Structural orientations (fractures, joints, faults, lineaments, bedding orientations, etc.) were collected with a standard Brunton compass during routine field examinations of geothermal phenomena in Colorado. Often multiple orientations were taken from one outcrop. Care was taken to ensure outcrops were "in place". Point data was collected with a hand-held GPS unit. The structural data is presented both as standard quadrant measurements and in format suitable for ESRI symbology Spatial Domain: Extent: Top: 4491528.924999 m Left: 207137.983196 m Right: 432462.310324 m Bottom: 4117211.772001 m Contact Information: Contact Organization: Geothermal Development Associates, Reno, Nevada Contact Person: Richard “Rick” Zehner Address: 3740 Barron Way City: Reno State: NV Postal Code: 89511 Country: USA Contact Telephone: 775-737-7806 Spatial Reference Information: Coordinate System: Universal Transverse Mercator (UTM) WGS’1984 Zone 13N False Easting: 500000.00000000 False Northing: 0.00000000 Central Meridian: -105.00000000 Scale Factor: 0.99960000 Latitude of Origin: 0.00000000 Linear Unit: Meter Datum: World Geodetic System 1984 (WGS ’1984) Prime Meridian: Greenwich Angular Unit: Degree Digital Form: Format Name: Shape file

  10. REVIVAL OF GRASS-ROOTS GEOTHERMAL EXPLORATION IN THE GREAT BASIN (WHERE TO LOOK FOR NEW GEOTHERMAL FIELDS) - A NEW APPROACH TO ASSESSING GEOTHERMAL POTENTIAL USING A GEOGRAPHIC INFORMATION SYSTEM parts IV and V

    Microsoft Academic Search

    Mark Coolbaugh; Rick Zehner; Corné Kreemer; Don Sawatzky; Gary Oppliger; David Blackwell; Lisa Shevenell; Jim Taranik; Gary Raines; Jim Faulds

    We propose to expand the existing GIS of geothermal systems in the Great Basin to include several key new features: 1) improved predictive maps of geothermal favorability based on new digital data on crustal strain, fault displacements, heat flux, and other data, 2) maps predicting which portions of the Great Basin are most likely to conceal geothermal systems, and 3)

  11. Numerical modeling of geothermal systems with applications to Krafla, Iceland and Olkaria, Kenya

    SciTech Connect

    Bodvarsson, G.S.

    1987-08-01

    The use of numerical models for the evaluation of the generating potential of high temperature geothermal fields has increased rapidly in recent years. In the present paper a unified numerical approach to the modeling of geothermal systems is discussed and the results of recent modeling of the Krafla geothermal field in Iceland and the Olkaria, Kenya, are described. Emphasis is placed on describing the methodology using examples from the two geothermal fields.

  12. Direct utilization of geothermal heat in cascade application to aquaculture and greenhouse systems at Navarro College. Final report, March 1, 1979-September 30, 1984

    SciTech Connect

    Smith, K.

    1984-09-01

    This final report documents the Navarro College geothermal use project, which is one of nineteen direct-use geothermal projects funded principally by DOE. The six-year project encompassed a broad range of technical, institutional, and economic activities including: resource and environmental assessment; well drilling and completion; system design, construction, and monitoring; economic analysis; and public awareness programs. Some of the project conclusions are that: (1) the 130/sup 0/F Central Texas geothermal resource can support additional geothermal development; (2) private sector economic incentives currently exist which encourage commercial development of this geothermal resource; (3) potential uses for this geothermal resource include water and space heating, aquacultural and agricultural heating uses, and fruit and vegetable dehydration; (4) high maintenance costs arising from the geofluids' scaling and corrosion characteristics can be avoided through proper analysis and design.

  13. Applied Microearthquake Techniques for Geothermal Resource Development

    E-print Network

    Foulger, G. R.

    Applied Microearthquake Techniques for Geothermal Resource Development Gillian R. Foulger1 & Bruce@usgs.gov Geothermal areas are often associated with microearthquake activity [Foulger, 1982; Foulger and Long, 1984], and these earthquakes have often been used to learn more about both exploited and unexploited geothermal systems

  14. Multiparameter fiber optic sensing system for monitoring enhanced geothermal systems

    SciTech Connect

    William A. Challener

    2014-12-04

    The goal of this project was to design, fabricate and test an optical fiber cable which supports multiple sensing modalities for measurements in the harsh environment of enhanced geothermal systems. To accomplish this task, optical fiber was tested at both high temperatures and strains for mechanical integrity, and in the presence of hydrogen for resistance to darkening. Both single mode (SM) and multimode (MM) commercially available optical fiber were identified and selected for the cable based on the results of these tests. The cable was designed and fabricated using a tube-within-tube construction containing two MM fibers and one SM fiber, and without supporting gel that is not suitable for high temperature environments. Commercial fiber optic sensing instruments using Raman DTS (distributed temperature sensing), Brillouin DTSS (distributed temperature and strain sensing), and Raleigh COTDR (coherent optical time domain reflectometry) were selected for field testing. A microelectromechanical systems (MEMS) pressure sensor was designed, fabricated, packaged, and calibrated for high pressure measurements at high temperatures and spliced to the cable. A fiber Bragg grating (FBG) temperature sensor was also spliced to the cable. A geothermal well was selected and its temperature and pressure were logged. The cable was then deployed in the well in two separate field tests and measurements were made on these different sensing modalities. Raman DTS measurements were found to be accurate to ���±5���°C, even with some residual hydrogen darkening. Brillouin DTSS measurements were in good agreement with the Raman results. The Rayleigh COTDR instrument was able to detect some acoustic signatures, but was generally disappointing. The FBG sensor was used to determine the effects of hydrogen darkening, but drift over time made it unreliable as a temperature or pressure sensor. The MEMS sensor was found to be highly stable and accurate to better than its 0.1% calibration.

  15. GEOLOGIC SETTING OF THE CHENA HOT SPRINGS GEOTHERMAL SYSTEM, ALASKA

    Microsoft Academic Search

    Amanda Kolker; Rainer Newberry; Jessica Larsen; Paul Layer; Patrick Stepp

    2007-01-01

    A belt of moderate-temperature geothermal activity runs east-west across central Alaska. Chena Hot Springs (CHS) is one of several Interior Alaskan hot springs in or near 55 Ma granites within Paleozoic metamorphic rocks. CHS is located within the CHS pluton, a composite body of quartz diorite, tonalite, granodiorite, and granite of both mid-Cretaceous and Early Tertiary ages. 40Ar\\/39Ar step heat

  16. Environmental impacts of open loop geothermal system on groundwater

    NASA Astrophysics Data System (ADS)

    Kwon, Koo-Sang; Park, Youngyun; Yun, Sang Woong; Lee, Jin-Yong

    2013-04-01

    Application of renewable energies such as sunlight, wind, rain, tides, waves and geothermal heat has gradually increased to reduce emission of CO2 which is supplied from combustion of fossil fuel. The geothermal energy of various renewable energies has benefit to be used to cooling and heating systems and has good energy efficiency compared with other renewable energies. However, open loop system of geothermal heat pump system has possibility that various environmental problems are induced because the system directly uses groundwater to exchange heat. This study was performed to collect data from many documents such as papers and reports and to summarize environmental impacts for application of open loop system. The environmental impacts are classified into change of hydrogeological factors such as water temperature, redox condition, EC, change of microbial species, well contamination and depletion of groundwater. The change of hydrogeological factors can induce new geological processes such as dissolution and precipitation of some minerals. For examples, increase of water temperature can change pH and Eh. These variations can change saturation index of some minerals. Therefore, dissolution and precipitation of some minerals such as quartz and carbonate species and compounds including Fe and Mn can induce a collapse and a clogging of well. The well contamination and depletion of groundwater can reduce available groundwater resources. These environmental impacts will be different in each region because hydrogeological properties and scale, operation period and kind of the system. Therefore, appropriate responses will be considered for each environmental impact. Also, sufficient study will be conducted to reduce the environmental impacts and to improve geothermal energy efficiency during the period that a open loop system is operated. This work was supported by the Energy Efficiency and Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.20123040110010).

  17. Geothermal Energy.

    ERIC Educational Resources Information Center

    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)

  18. Seismic tomography and dynamics of geothermal and natural hydrothermal systems in the south of Bandung, Indonesia

    NASA Astrophysics Data System (ADS)

    Jousset, Philippe; Sule, Rachmat; Diningrat, Wahyuddin; Syahbana, Devy; Schuck, Nicole; Akbar, Fanini; Kusnadi, Yosep; Hendryana, Andri; Nugraha, Andri; Ryannugroho, Riskiray; Jaya, Makki; Erbas, Kemal; Bruhn, David; Pratomo, Bambang

    2015-04-01

    The structure and the dynamics of geothermal reservoirs and hydrothermal systems allows us to better assess geothermal resources in the south of Bandung. A large variety of intense surface manifestations like geysers, hot-steaming grounds, hot water pools, and active volcanoes suggest an intimate coupling between volcanic, tectonic and hydrothermal processes in this area. We deployed a geophysical network around geothermal areas starting with a network of 30 seismic stations including high-dynamic broadband Güralp and Trillium sensors (0.008 - 100 Hz) and 4 short-period (1 Hz) sensors from October 2012 to December 2013. We extended the network in June 2013 with 16 short-period seismometers. Finally, we deployed a geodetic network including a continuously recording gravity meter, a GPS station and tilt-meters. We describe the set-up of the seismic and geodetic networks and we discuss observations and results. The earthquakes locations were estimated using a non-linear algorithm, and revealed at least 3 seismic clusters. We perform joint inversion of hypo-center and velocity tomography and we look at seismic focal mechanisms. We develop seismic ambient noise tomography. We discuss the resulting seismic pattern within the area and relate the structure to the distribution of hydrothermal systems. We aim at searching possible structural and dynamical links between different hydrothermal systems. In addition, we discuss possible dynamical implications of this complex volcanic systems from temporal variations of inferred parameters. The integration of those results allows us achieving a better understanding of the structures and the dynamics of those geothermal reservoirs. This approach contributes to the sustainable and optimal exploitation of the geothermal resource in Indonesia.

  19. Natural analogs for enhanced heat recovery from geothermal systems

    SciTech Connect

    Nielson, Dennis L.

    1996-01-24

    High-temperature hydrothermal systems are physically and chemically zoned with depth. The energy input is from a magmatic zone, intruded by igneous bodies, that may also contribute variable amounts of magmatic fluid to the system. The heat source is directly overlain by a section of rocks, that due to their elevated temperature, respond to stress in a ductile fashion. The ductile zone is, in turn, overlain by a section of rocks that respond to stress in a brittle fashion, where water is able to circulate through fractures (the geothermal reservoir) and will be termed the hydrothermal circulation zone. Ancient and modern high-temperature geothermal systems show a predictable sequence of evolutionary events affecting these stratified zones. Metamorphic core complexes are uplifts, formed in highly extended terrains, that expose fossil brittle-ductile transition zones. Formerly ductile rocks have had brittle fractures superimposed on them, and meteoric hydrothermal systems are associated with the brittle fracturing. Porphyry copper deposits typically evolve from magmatic to meteoric hydrothermal systems. At the Larderello geothermal system, the brittle- ductile transition has been mapped using reflection seismology, and the zone has been penetrated by the San Pompeo 2 well where temperatures >420°C were encountered. Although neo-granitic dikes have been penetrated by drilling in the Larderello area, the brittle- ductile transition is largely above the inferred plutonic heat source. In the Geysers system, in contrast, the present steam system has been superimposed on young plutonic rocks and the inferred brittle-ductile transition is present at a depth of about 4.7 km within the plutonic rocks. As hydrothermal reservoirs are depleted, or surface facilities are restricted by environmental considerations, interest will turn to the deeper portions of known systems. Japan already has an aggressive program to develop Deep-seated and Magma-Ambient resources. This program, as well as others that develop methods for the mining of heat past the stage of primary production, will be termed Enhanced Heat Recovery (EHR). Examples of the evolution of natural systems suggest the methods by which deep geothermal systems can be exploited. The key to the exploitation of deep geothermal systems is successful injection of water into rocks above the brittle-ductile transition, producing steam, cooling the rocks and driving the brittle-ductile transition to deeper levels. Under this scenario, injection wells may be more expensive and require more thoughtful planning than production wells.

  20. Summary of geothermal drilling activities in the Western United States

    SciTech Connect

    Tanji, S.A.

    1982-07-01

    Geothermal drilling in the area which extends from the Geysers, north of San Francisco to the Imperial Valley in the south, then west to the Mojave Desert in California to Northern Nevada is emphasized. It is revealed that the Geysers' geothermal field, owned by Pacific Gas and Electric, is the largest geothermal field in the world, containing over 200 steam wells which average about 7,500 ft in depth and generate more than 900,000 kilowatts of electricity. PGandE operates the power plants while drilling companies provide the steam. Average steam production per well is 150,000 lbs per hr., with 13 wells needed to supply steam for a 110-MWe plant. From January 1970 to June 1979, 55% of all US geothermal wells were drilled in the Geyser, the only developed area of the 1970s. It is noted that the US Geological Survey has been encouraged by results of a pair of geothermal test wells.

  1. Geothermal Energy Program overview

    SciTech Connect

    Not Available

    1991-12-01

    The mission of the Geothermal Energy Program is to develop the science and technology necessary for tapping our nation's tremendous heat energy sources contained with the Earth. Geothermal energy is a domestic energy source that can produce clean, reliable, cost- effective heat and electricity for our nation's energy needs. Geothermal energy -- the heat of the Earth -- is one of our nation's most abundant energy resources. In fact, geothermal energy represents nearly 40% of the total US energy resource base and already provides an important contribution to our nation's energy needs. Geothermal energy systems can provide clean, reliable, cost-effective energy for our nation's industries, businesses, and homes in the form of heat and electricity. The US Department of Energy's (DOE) Geothermal Energy Program sponsors research aimed at developing the science and technology necessary for utilizing this resource more fully. Geothermal energy originates from the Earth's interior. The hottest fluids and rocks at accessible depths are associated with recent volcanic activity in the western states. In some places, heat comes to the surface as natural hot water or steam, which have been used since prehistoric times for cooking and bathing. Today, wells convey the heat from deep in the Earth to electric generators, factories, farms, and homes. The competitiveness of power generation with lower quality hydrothermal fluids, geopressured brines, hot dry rock, and magma ( the four types of geothermal energy) still depends on the technical advancements sought by DOE's Geothermal Energy Program.

  2. Geology of the Beowawe geothermal system, Eureka and Lander Counties, Nevada

    SciTech Connect

    Struhsacker, E.M.

    1980-07-01

    A geologic study is described undertaken to evaluate the nature of structural and stratigraphic controls within the Beowawe geothermal system, Eureka and Lander Counties, Nevada. This study includes geologic mapping at a scale of 1:24,000 and lithologic logs of deep Chevron wells. Two major normal fault systems control the configuration of the Beowawe geothermal system. Active hot springs and sinter deposits lie along the Malpais Fault zone at the base of the Malpais Rim. The Malpais Rim is one of several east-northeast-striking, fault-bounded cuestas in north central Nevada. A steeply inclined scarp slope faces northwest towards Whirlwind Valley. The general inclination of the volcanic rocks on the Malpais dip slope is 5/sup 0/ to 10/sup 0/ southeast.

  3. Passive Seismic Monitoring of Mine-scale Geothermal Activity: A Trial at Lihir Open Pit Mine

    Microsoft Academic Search

    X. Luo; A. Creighton; J. Gough

    2010-01-01

    The Lihir open pit mine in Papua New Guinea is located inside an old volcano where geothermal activity is strongly present.\\u000a Outbursts of hot water and steam into the mining areas were a major safety concern. Passive seismic monitoring was carried\\u000a out at the mine to investigate whether the geothermal activities could be detected and located using microseismic techniques\\u000a in

  4. Clay minerals related to the hydrothermal activity of the Bouillante geothermal field (Guadeloupe)

    NASA Astrophysics Data System (ADS)

    Mas, A.; Guisseau, D.; Patrier Mas, P.; Beaufort, D.; Genter, A.; Sanjuan, B.; Girard, J. P.

    2006-11-01

    The geothermal field of Bouillante (Guadeloupe, FWI) is a high-enthalpy hydrothermal system emplaced in submarine volcanoclastic formations (hyaloclastites, scarce lava flows) and subaerial formations (andesitic lava flows, pyroclastites, lahars) which belong to the Lesser Antilles arc. Three directional wells were drilled in 2001 to optimize the productivity of the geothermal field up to 15 MWe and to investigate the vertical distribution of clay alteration from the surface area down to a depth of 1000 m where temperatures exceed 250 °C. Special attention has been paid to the "clay signature" of the fractured zones which channel the present geothermal fluids. Three successive zones, dominated, respectively by dioctahedral smectite, illite and chlorite were identified at increasing depths. Alteration petrography indicates that these mineralogical clay zones result from the spatial superimposition of at least two successive alteration stages. The first one, assimilated to a propylitic alteration stage, affected all parts of the system and consisted of crystallization of trioctahedral phyllosilicates (chlorite or corrensite), Ca-silicates (heulandite-clinoptilolite, prehnite, pumpelleyite, wairakite and epidote), quartz and minor calcite in replacement of most of the primary minerals of the intersected volcanic or volcanoclastic formations. The later stage of alteration is related to the circulation of the present geothermal fluids and is assimilated to argillic or phyllic alteration. It consists of a more or less intense argillization which results from the crystallization of aluminous dioctahedral clay phases (smectite, illite ± I-S mixed layers, and accessory kaolinite) associated with quartz, calcite, hematite or pyrite. The permeable zones which channel most of the present geothermal fluids are fracture controlled and do not contain specific clay parageneses. However the illite ± I-S mixed layers minerals differ from those of the surroundings by specific properties including both crystal structure and texture. These specific properties (decrease in the expandable component of the illitic material, increase of the illite crystallinity) can be controlled by the nucleation/growth rates operating in zones of active flow regime. Being mainly a product of the earlier propylitic alteration stage, chlorites are much less informative on the fracture controlled permeable levels. However, the compositional variations of chlorites recorded within the shallower fractured zone suggest a significant change in fO 2 conditions related to early circulation of fluids along the major near west striking normal faults (Plateau fault).

  5. Hydrocarbon anomaly in soil gas as near-surface expressions of upflows and outflows in geothermal systems

    SciTech Connect

    Ong, H.L.; Higashihara, M.; Klusman, R.W.; Voorhees, K.J.; Pudjianto, R.; Ong, J

    1996-01-24

    A variety of hydrocarbons, C1 - C12, have been found in volcanic gases (fumarolic) and in geothermal waters and gases. The hydrocarbons are thought to have come from products of pyrolysis of kerogen in sedimentary rocks or they could be fed into the geothermal system by the recharging waters which may contain dissolved hydrocarbons or hydrocarbons extracted by the waters from the rocks. In the hot geothermal zone, 300°+ C, many of these hydrocarbons are in their critical state. It is thought that they move upwards due to buoyancy and flux up with the upflowing geothermal fluids in the upflow zones together with the magmatic gases. Permeability which could be provided by faults, fissures, mini and micro fractures are thought to provide pathways for the upward flux. A sensitive technique (Petrex) utilizing passive integrative adsorption of the hydrocarbons in soil gas on activated charcoal followed by desorption and analysis of the hydrocarbons by direct introduction mass spectrometry allows mapping of the anomalous areas. Surveys for geothermal resources conducted in Japan and in Indonesia show that the hydrocarbon anomaly occur over known fields and over areas strongly suspected of geothermal potential. The hydrocarbons found and identified were n-paraffins (C7-C9) and aromatics (C7-C8). Detection of permeable, i.e. active or open faults, parts of older faults which have been reactivated, e.g. by younger intersecting faults, and the area surrounding these faulted and permeable region is possible. The mechanism leading to the appearance of the hydrocarbon in the soil gas over upflow zones of the geothermal reservoir is proposed. The paraffins seems to be better pathfinders for the location of upflows than the aromatics. However the aromatics may, under certain circumstances, give better indications of the direction of the outflow of the geothermal system. It is thought that an upflow zone can be defined when conditions exist where the recharging waters containing the hydrocarbons feed into the geothermal kitchen. The existence of open and active faults, fissures, mini and micro fractures allow sufficient permeability for the gases to flux up and express themselves at the surface as hydrocarbon anomaly in the soil gas. When any of the requirements is absent, i.e. in the absence of the recharging waters, hydrocarbons, temperature, or permeability, no anomaly can be expected. It assumes a dynamic convective system, i.e. recharging waters, upflow and outflow. The anomalies however can define to a certain extent, regions of geothermal upflow, buoyant transport of gases, and frequently down-gradient of cooling waters.

  6. I/S and C/S mixed layers, some indicators of recent physical-chemical changes in active geothermal systems: The case study of Chipilapa (El Salvador)

    SciTech Connect

    Beaufort, D.; Papapanagiotou, P.; patrier, P.; Fouillac, A.M.; Traineau, H.

    1996-01-24

    I/S and C/S mixed layers from the geothermal field of Chipilapa (El Salvador) have been studied in details in order to reevaluate their potential use as indicator of the thermodynamic conditions in which they were formed. It is funded that overprinting of clay bearing alteration stages is common. For a given alteration stage, the spatial variation of I/S and C/S mixed layer ininerals is controlled by kinetics of mixed layer transformation and not only by temperature. Clay geo-thermometers cannot give reliable results because the present crystal-chemical states of the I/S and C/S mixed layers is not their initial state, it was aquired during the overall hydrothermal history which post dated the nucleation of smectitic clay material at high temperature. Occurrences of smectites or smectite-rich mixed layers at high temperature in reservoirs is a promising guide for reconstruct the zones in which boiling or mixing of non isotherinal fluids occurred very recently or still presently.

  7. Feasibility study of sedimentary enhanced geothermal systems using reservoir simulation

    NASA Astrophysics Data System (ADS)

    Cho, Jae Kyoung

    The objective of this research is to evaluate the preliminary feasibility of commercial geothermal projects, from a sedimentary reservoir with low permeability that requires productivity enhancement, using numerical reservoir simulation. The performance of a sedimentary geothermal reservoir is investigated in terms of reservoir hydraulics and thermal evolution. To build a reliable benchmark for simulation study, validation of the numerical reservoir model with respect to an analytical model is presented, and the process to achieve an acceptable match between the numerical and analytical solutions is described. The analytical model used in this study is based on the work of Gringarten (1978), which consists of a conceptual geothermal reservoir, considering an injection and production well doublet in a homogeneous porous media. A commercial thermal reservoir simulator (STARS from Computer Modeling Group, CMG) is used in this work for numerical modeling. In order to reproduce the analytical model results, the numerical simulation model is modified to include the same assumptions of the analytical model. Simulation model parameters that make the numerical results deviate from the analytical solution, such as the grid block size, time step and no-flow boundary are identified and investigated. An analytical tracer test model proposed by Shook (2000) is numerically modeled. This model allows us to predict the time when the temperature of the produced water decreases by capturing a tracer component at production well. Reservoir simulation models with different porosity and permeability distribution are tested to see the effects of reservoir inhomogeneity and anisotropy. In particular, premature thermal breakthrough due to the presence of high permeability streak in a reservoir model is simulated. In an effort to apply the knowledge we obtained from the analytical solutions, the effects of reservoir rock and water properties, as a function of pressure and temperature, are investigated. Especially, water density, viscosity and rock heat capacity play a significant role in reservoir performance. The Permian Lyons formation in the Denver Basin is selected for this preliminary study. Well log data around the area of interest are collected and borehole temperature data are analyzed to estimate the geothermal potential of the target area and it follows that the target formation has a geothermal gradient as high as 72 °C/km. Based on the well log data, hypothetical reservoir simulation models are build and tested to access the hydraulic and thermal performance. It turns out that the target formation is marginally or sub-marginally commercial in terms of its formation conductivity. Therefore, the target formation may require reservoir stimulation for commercially viable power generation. Lastly, reservoir simulation models with average petrophysical properties obtained from the well log analysis of the target formation are built. In order to account for overburden and underburden heat transfer for confined reservoirs, low permeability layers representing shale cap/bed rocks are attached to the top and bottom of the reservoir layers. The dual permeability concept is applied to the reservoir layers to model induced fracture networks by reservoir stimulation. The simulation models are tested by changing fracture conductivity and shape factor. The results show that a balance between hydraulic and thermal performance should be achieved to meet the target flow rate and sustainability of 30 years' uninterrupted operation of geothermal electricity power generation. Ineffective reservoir stimulation could result in failing to create a producing reservoir with appropriate productivity index or causing premature thermal breakthrough or short-circuiting which advances the end of geothermal systems. Therefore, Enhanced Geothermal Systems (EGS) should be engineered to secure producing performance and operational sustainability simultaneously.

  8. Off peak geothermal heat pump storage system

    SciTech Connect

    Drake, M.S.

    1986-03-01

    The basic design of a system installed in the Columbus, Ohio Zoo is described. The distribution system is described in detail. The control system is microprocessor controlled, with about 50 monitoring points. Preliminary evaluations have indicated that the system can operate with an overall coefficient of performance in excess of 3.5. 1 figure.

  9. E-Alerts: Energy (geothermal energy). E-mail newsletter

    SciTech Connect

    NONE

    1999-04-01

    The paper discusses geothermal exploration and prospecting methods and equipment; Geothermal resources; Geothermal energy conversion; Geology applied to geothermal systems; Drilling; Reservoirs; Extraction; Site selection; Geothermal power plants; Corrosion studies; and Materials used in geothermal systems.

  10. Energy Return On Investment of Engineered Geothermal Systems Data

    DOE Data Explorer

    Mansure, Chip

    EROI is a ratio of the energy delivered to the consumer to the energy consumed to build, operate, and decommission the facility. EROI is important in assessing the viability of energy alternatives. Currently EROI analyses of geothermal energy are either out-of-date, of uncertain methodology, or presented online with little supporting documentation. This data set is a collection of files documenting data used to calculate the Energy Return On Investment (EROI) of Engineered Geothermal Systems (EGS) and erratum to publications prior to the final report. Final report is available from the OSTI web site (http://www.osti.gov/geothermal/). Data in this collections includes the well designs used, input parameters for GETEM, a discussion of the energy needed to haul materials to the drill site, the baseline mud program, and a summary of the energy needed to drill each of the well designs. EROI is the ratio of the energy delivered to the customer to the energy consumed to construct, operate, and decommission the facility. Whereas efficiency is the ratio of the energy delivered to the customer to the energy extracted from the reservoir.

  11. Beneficial effects of groundwater entry into liquid-dominated geothermal systems

    SciTech Connect

    Lippmann, M.J. (Lawrence Berkeley Lab., CA (USA)); Truesdell, A.H. (Geological Survey, Menlo Park, CA (USA))

    1990-04-01

    In all active liquid-dominated geothermal systems there is continuous circulation of mass and transfer of heat, otherwise they would slowly cool and fade away. In the natural state these systems are in dynamic equilibrium with the surrounding colder groundwater aquifers. The ascending geothermal fluids cool conductively, boil, or mix with groundwaters, and ultimately may discharge at the surface as fumaroles or hot springs. With the start of fluid production and the lowering of reservoir pressure, the natural equilibrium is disrupted and cooler groundwater tends to enter the reservoir. Improperly constructed or damaged wells, and wells located near the margins of the geothermal system, exhibit temperature reductions (and possibly scaling from mixing of chemically distinct fluids) as the cooler-water moves into the reservoir. These negative effects, especially in peripheral wells are, however, compensated by the maintenance of reservoir pressure and a reduction in reservoir boiling that might result in mineral precipitation in the formation pores and fractures. The positive effect of cold groundwater entry on the behavior of liquid-dominated system is illustrated by using simple reservoir models. The simulation results show that even though groundwater influx into the reservoir causes cooling of fluids produced from wells located near the cold-water recharge area, it also reduces pressure drawdown and boiling in the exploited zone, and sweeps the heat stored in the reservoir rocks toward production wells, thus increasing the productive life of the wells and field. 9 refs.

  12. Proceedings of a Topical Meeting On Small Scale Geothermal Power Plants and Geothermal Power Plant Projects

    SciTech Connect

    None

    1986-02-12

    These proceedings describe the workshop of the Topical Meeting on Small Scale Geothermal Power Plants and Geothermal Power Plant Projects. The projects covered include binary power plants, rotary separator, screw expander power plants, modular wellhead power plants, inflow turbines, and the EPRI hybrid power system. Active projects versus geothermal power projects were described. In addition, a simple approach to estimating effects of fluid deliverability on geothermal power cost is described starting on page 119. (DJE-2005)

  13. Summary of geothermal exploration activity in the State of Washington from 1978 to 1983. Final report

    SciTech Connect

    Korosec, M.A.

    1984-01-01

    Project activity is summarized with references to the publications produced. Project findings are reported as they relate to specific geothermal resource target areas. Some major projects of the goethermal exploration program are: thermal and mineral spring chemistry, heat flow drilling, temperature gradient measurements, Cascade Range regional gravity, geohydrology study of the Yakima area, low temperature geothermal resources, geology, geochemistry of Cascade Mountains volcanic rocks, and soil mercury studies. (MHR)

  14. Assessing the role of ancient and active geothermal systems in oil-reservoir evolution in the eastern Basin and Range province, western USA. Annual progress report, June 1, 1992--May 31, 1993

    SciTech Connect

    Hulen, J.B.

    1993-07-01

    Results of our research on the oil fields of the Basin and Range province of the western USA continue to support the following concept: Convecting, moderate-temperature geothermal systems in this region have fostered and in some cases critically influenced the generation, migration, and entrapment of oil. At one Basin-Range field (Grant Canyon), oil-bearing and aqueous fluid inclusions in late-stage hydrothermal quartz were entrapped at temperatures comparable to those now prevailing at reservoir depths (120--130{degrees}C); apparent salinities of the aqueous varieties match closely the actual salinity of the modern, dilute oil-field waters. The inclusion-bearing quartz has the oxygen-isotopic signature for precipitation of the mineral at contemporary temperatures from modern reservoir waters. Measured and fluid-inclusion temperatures define near-coincident isothermal profiles through the oil-reservoir interval, a phenomenon suggesting ongoing heat and mass transfer. These findings are consistent with a model whereby a still-active, convectively circulating, meteoric-hydrothermal system: (1) enhanced porosity in the reservoir rock through dissolution of carbonate; (2) hydrothermally sealed reservoir margins; (3) transported oil to the reservoirs from a deep source of unknown size and configuration; and (4) possibly accelerated source-rock maturation through an increase in the local thermal budget. Grant Canyon and other Basin-Range oil fields are similar to the oil-bearing, Carlin-type, sediment-hosted, disseminated gold deposits of the nearby Alligator Ridge district. The oil fields could represent either weakly mineralized analogues of these deposits, or perhaps an incipient phase in their evolution.

  15. Is it only CO2 that matters? A life cycle perspective on shallow geothermal systems

    Microsoft Academic Search

    Dominik Saner; Ronnie Juraske; Markus Kübert; Philipp Blum; Stefanie Hellweg; Peter Bayer

    2010-01-01

    Shallow geothermal systems such as open and closed geothermal heat pump (GHP) systems are considered to be an efficient and renewable energy technology for cooling and heating of buildings and other facilities. The numbers of installed ground source heat pump (GSHP) systems, for example, is continuously increasing worldwide. The objective of the current study is not only to discuss the

  16. Is it only CO 2 that matters? A life cycle perspective on shallow geothermal systems

    Microsoft Academic Search

    Dominik Saner; Ronnie Juraske; Markus Kübert; Philipp Blum; Stefanie Hellweg; Peter Bayer

    2010-01-01

    Shallow geothermal systems such as open and closed geothermal heat pump (GHP) systems are considered to be an efficient and renewable energy technology for cooling and heating of buildings and other facilities. The numbers of installed ground source heat pump (GSHP) systems, for example, is continuously increasing worldwide. The objective of the current study is not only to discuss the

  17. National Geothermal Data System: State Geological Survey Contributions to Date

    NASA Astrophysics Data System (ADS)

    Patten, K.; Allison, M. L.; Richard, S. M.; Clark, R.; Love, D.; Coleman, C.; Caudill, C.; Matti, J.; Musil, L.; Day, J.; Chen, G.

    2012-12-01

    In collaboration with the Association of American State Geologists the Arizona Geological Survey is leading the effort to bring legacy geothermal data to the U.S. Department of Energy's National Geothermal Data System (NGDS). NGDS is a national, sustainable, distributed, interoperable network of data and service (application) providers entering its final stages of development. Once completed the geothermal industry, the public, and policy makers will have access to consistent and reliable data, which in turn, reduces the amount of staff time devoted to finding, retrieving, integrating, and verifying information. With easier access to information, the high cost and risk of geothermal power projects (especially exploration drilling) is reduced. This presentation focuses on the scientific and data integration methodology as well as State Geological Survey contributions to date. The NGDS is built using the U.S. Geoscience Information Network (USGIN) data integration framework to promote interoperability across the Earth sciences community and with other emerging data integration and networking efforts. Core to the USGIN concept is that of data provenance; by allowing data providers to maintain and house their data. After concluding the second year of the project, we have nearly 800 datasets representing over 2 million data points from the state geological surveys. A new AASG specific search catalog based on popular internet search formats enables end users to more easily find and identify geothermal resources in a specific region. Sixteen states, including a consortium of Great Basin states, have initiated new field data collection for submission to the NGDS. The new field data includes data from at least 21 newly drilled thermal gradient holes in previously unexplored areas. Most of the datasets provided to the NGDS are being portrayed as Open Geospatial Consortium (OGC) Web Map Services (WMS) and Web Feature Services (WFS), meaning that the data is compatible with a variety of visualization software. Web services are ideal for the NGDS data for a number of reasons including that they preserve data ownership in that they are read only and new services can be deployed to meet new requirements without modifying existing applications.

  18. Life-cycle analysis results of geothermal systems in comparison to other power systems

    Microsoft Academic Search

    J. L. Sullivan; C. E. Clark; J. Han; M. Wang

    2010-01-01

    A life-cycle energy and greenhouse gas emissions analysis has been conducted with Argonne National Laboratory's expanded Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model for geothermal power-generating technologies, including enhanced geothermal, hydrothermal flash, and hydrothermal binary technologies. As a basis of comparison, a similar analysis has been conducted for other power-generating systems, including coal, natural gas combined

  19. A geochemical reconnaissance of the Alid volcanic center and geothermal system, Danakil depression, Eritrea

    USGS Publications Warehouse

    Lowenstern, J. B.; Janik, C.J.; Fournier, R.O.; Tesfai, T.; Duffield, W.A.; Clynne, M.A.; Smith, James G.; Woldegiorgis, L.; Weldemariam, K.; Kahsai, G.

    1999-01-01

    Geological and geochemical studies indicate that a high-temperature geothermal system underlies the Alid volcanic center in the northern Danakil depression of Eritrea. Alid is a very late-Pleistocene structural dome formed by shallow intrusion of rhyolitic magma, some of which vented as lavas and pyroclastic flows. Fumaroles and boiling pools distributed widely over an area of ~10 km2 on the northern half of Alid suggest that an active hydrothermal system underlies much of that part of the mountain. Geothermometers indicate that the fumarolic gases are derived from a geothermal system with temperatures >225??C. The isotopic composition of condensed fumarolic steam is consistent with these temperatures and implies that the source water is derived primarily from either lowland meteoric waters or fossil Red Sea water, or both. Some gases vented from the system (CO2, H2S and He) are largely magmatic in origin. Permeability beneath the volcanic center may be high, given the amount of intrusion-related deformation and the active normal faulting within the Danakil depression.Geological and geochemical studies indicate that a high-temperature geothermal system underlies the Alid volcanic center in the northern Danakil depression of Eritrea. Alid is a very late-Pleistocene structural dome formed by shallow intrusion of rhyolitic magma, some of which vented as lavas and pyroclastic flows. Fumaroles and boiling pools distributed widely over an area of approx. 10 km2 on the northern half of Alid suggest that an active hydrothermal system underlies much of that part of the mountain. Geothermometers indicate that the fumarolic gases are derived from a geothermal system with temperatures >225??C. The isotopic composition of condensed fumarolic steam is consistent with these temperatures and implies that the source water is derived primarily from either lowland meteoric waters or fossil Red Sea water, or both. Some gases vented from the system (CO2, H2S and He) are largely magmatic in origin. Permeability beneath the volcanic center may be high, given the amount of intrusion-related deformation and the active normal faulting within the Danakil depression.

  20. Geopressured-geothermal well activities in Louisiana. Annual report, 1 January 1991--31 December 1991

    SciTech Connect

    John, C.J.

    1992-10-01

    Since September 1978, microseismic networks have operated continuously around US Department of Energy (DOE) geopressured-geothermal well sites to monitor any microearthquake activity in the well vicinity. Microseismic monitoring is necessary before flow testing at a well site to establish the level of local background seismicity. Once flow testing has begun, well development may affect ground elevations and/or may activate growth faults, which are characteristic of the coastal region of southern Louisiana and southeastern Texas where these geopressured-geothermal wells are located. The microseismic networks are designed to detest small-scale local earthquakes indicative of such fault activation. Even after flow testing has ceased, monitoring continues to assess any microearthquake activity delayed by the time dependence of stress migration within the earth. Current monitoring shows no microseismicity in the geopressured-geothermal prospect areas before, during, or after flow testing.

  1. Low Temperature Geothermal Electricity Generation: Google Earth Virtual Field Trip Activity

    NSDL National Science Digital Library

    This exploration takes students to Chena Hot Springs Resort in Alaska where they will learn how to produce low temperature geothermal electricity. Teacher's guide, activity sheet and PowerPoint presenation included. The 2008 ATEEC Fellows Institute brought 18 environmental science community college and high school instructors to Alaska. They created virtual field trips using Google Earth. In the activity, explore Chena Hot Springs Resort in Alaska to learn about low temperature geothermal electricity generation. Chena Hot Springs runs their entire facility on renewable energy. Learn how they do it why they do it and the engineering challenges along the way. This activity includes numerous turnkey teaching resources such as a PowerPoint presentation explaining the geothermal heat exchanging process, video interviews with environmental engineers, a teacher's guide and student activity. Users must create a free login to access this resource.

  2. Dynamics of hydrothermal seeps from the Salton Sea geothermal system (California, USA) constrained by temperature monitoring

    E-print Network

    Svensen, Henrik

    Dynamics of hydrothermal seeps from the Salton Sea geothermal system (California, USA) constrained-, and petroleum-bearing seeps are part of the Salton Sea geothermal system (SSGS) in southern California. Carbon hot and cold pulses in the gryphon temperature time series, with amplitudes up to 3°C. These pulses

  3. Parametric Analysis of the Factors Controlling the Costs of Sedimentary Geothermal Systems - Preliminary Results (Poster)

    SciTech Connect

    Augustine, C.

    2013-10-01

    Parametric analysis of the factors controlling the costs of sedimentary geothermal systems was carried out using a modified version of the Geothermal Electricity Technology Evaluation Model (GETEM). The sedimentary system modeled assumed production from and injection into a single sedimentary formation.

  4. Prospecting for a Blind Geothermal System Utilizing Geologic and Geophysical Data, Seven Troughs Range, Northwestern Nevada

    NASA Astrophysics Data System (ADS)

    Forson, Corina

    To aid in the discovery and evaluation of blind resources, it is important to utilize geologic, geophysical, and geochemical techniques to find the required elements (e.g., heat source, fluid to transport the heat, and permeability in a reservoir) for geothermal energy production. Based on a regional low resistivity anomaly discovered through a reconnaissance magnetotelluric (MT) survey, detailed geologic mapping, structural analysis, and a 2 m temperature survey were conducted to delineate the most likely areas for blind geothermal activity in the Seven Troughs Range, Nevada. The Seven Troughs Range resides in the northwestern Basin and Range province 190 km northeast of Reno and 50 km northwest of Lovelock in western Nevada. There is no known geothermal system in the area. Mesozoic metasedimentary strata and intrusions dominate the northern and southern parts of the range but are nonconformably overlain by a thick sequence (~ 1.5 km) of Oligocene to Miocene volcanic and volcaniclastic rocks and Quaternary sediments in the central part of the range. The southern part of the range consists of a basement horst block bounded by two major range-front faults, with Holocene fault scarps marking the more prominent fault on the east side of the range. In contrast, several gently to moderately west-tilted fault blocks, with good exposures of the Tertiary volcanic strata and bounded by a series of steeply east-dipping normal faults, characterize the central part of the range. Kinematic analysis of faults in the range and regional relations indicate a west-northwest-trending extension direction. Accordingly, slip and dilation tendency analyses suggest that north-northeast striking faults are the most favorably oriented for reactivation and fluid flow under the current stress field. Two areas in the Seven Troughs Range have a favorable structural setting for generating permeability and channeling geothermal fluids to the near surface: 1) A major right step in the range-front fault and concomitant fault intersection on the east side of the Seven Troughs Range. Slightly elevated 2 m temperatures (~15° C vs. background temperatures of 11-12° C) have been found in this vicinity. 2) A left step in the range-front fault and attendant fault termination on the west side of the range in the vicinity of Porter Spring. This area has the highest recorded 2 m temperatures (~19° C). Although the 2 m temperature survey does not reflect the presence of hot geothermal fluids near the surface at these locations, the 2D low resistivity MT anomaly and favorable structural settings warrant further analysis for blind geothermal systems in the area.

  5. Mantle helium and carbon isotopes in Separation Creek Geothermal Springs, Three Sisters area, Central Oregon: Evidence for renewed volcanic activity or a long term steady state system?

    Microsoft Academic Search

    M. C. van Soest; B. M. Kennedy; W. C. Evans; R. H. Mariner

    2002-01-01

    Cold bubbling springs in the Separation Creek area, the locus of current uplift at South Sister volcano show strong mantle signatures in helium and carbon isotopes and COâ\\/³He. This suggests the presence of fresh basaltic magma in the volcanic plumbing system. Currently there is no evidence to link this system directly to the uplift, which started in 1998. To the

  6. Active Management of Integrated Geothermal-CO2 Storage Reservoirs in Sedimentary Formations

    SciTech Connect

    Buscheck, Thomas A.

    2012-01-01

    Active Management of Integrated Geothermal–CO2 Storage Reservoirs in Sedimentary Formations: An Approach to Improve Energy Recovery and Mitigate Risk: FY1 Final Report The purpose of phase 1 is to determine the feasibility of integrating geologic CO2 storage (GCS) with geothermal energy production. Phase 1 includes reservoir analyses to determine injector/producer well schemes that balance the generation of economically useful flow rates at the producers with the need to manage reservoir overpressure to reduce the risks associated with overpressure, such as induced seismicity and CO2 leakage to overlying aquifers. Based on a range of well schemes, techno-economic analyses of the levelized cost of electricity (LCOE) are conducted to determine the economic benefits of integrating GCS with geothermal energy production. In addition to considering CO2 injection, reservoir analyses are conducted for nitrogen (N2) injection to investigate the potential benefits of incorporating N2 injection with integrated geothermal-GCS, as well as the use of N2 injection as a potential pressure-support and working-fluid option. Phase 1 includes preliminary environmental risk assessments of integrated geothermal-GCS, with the focus on managing reservoir overpressure. Phase 1 also includes an economic survey of pipeline costs, which will be applied in Phase 2 to the analysis of CO2 conveyance costs for techno-economics analyses of integrated geothermal-GCS reservoir sites. Phase 1 also includes a geospatial GIS survey of potential integrated geothermal-GCS reservoir sites, which will be used in Phase 2 to conduct sweet-spot analyses that determine where promising geothermal resources are co-located in sedimentary settings conducive to safe CO2 storage, as well as being in adequate proximity to large stationary CO2 sources.

  7. Development of geothermal logging systems in the United States

    SciTech Connect

    Lysne, P.

    1994-04-01

    Logging technologies developed for hydrocarbon resource evaluation have not migrated into geothermal applications even though data so obtained would strengthen reservoir characterization efforts. Two causative issues have impeded progress: (1) there is a general lack of vetted, high-temperature instrumentation, and (2) the interpretation of log data generated in a geothermal formation is in its infancy. Memory-logging tools provide a path around the first obstacle by providing quality data at a low cost. These tools feature on-board computers that process and store data, and newer systems may be programmed to make decisions. Since memory tools are completely self-contained, they are readily deployed using the slick line found on most drilling locations. They have proven to be rugged, and a minimum training program is required for operator personnel. Present tools measure properties such as temperature and pressure, and the development of noise, deviation, and fluid conductivity logs based on existing hardware is relatively easy. A more complex geochemical tool aimed at a quantitative analysis of (potassium, uranium and thorium) is in the calibration phase, and it is expandable into all nuclear measurements common in the hydrocarbon industry. A fluid sampling tool is in the design phase. All tools are designed for operation at conditions exceeding 400 C, and for deployment in the slim holes produced by mining-coring operations. Partnerships are being formed between the geothermal industry and scientific drilling programs to define and develop inversion algorithms relating raw tool data to more pertinent information. These cooperative efforts depend upon quality guidelines such as those under development within the international Ocean Drilling Program.

  8. Geopressured-geothermal well activities in Louisiana. Annual report, 1 January 1991--31 December 1991

    Microsoft Academic Search

    1992-01-01

    Since September 1978, microseismic networks have operated continuously around US Department of Energy (DOE) geopressured-geothermal well sites to monitor any microearthquake activity in the well vicinity. Microseismic monitoring is necessary before flow testing at a well site to establish the level of local background seismicity. Once flow testing has begun, well development may affect ground elevations and\\/or may activate growth

  9. Geothermal investigations in an area of induced seismic activity, northern São Paulo State, Brazil

    Microsoft Academic Search

    Tereza Higashi Yamabe; Valiya M. Hamza

    1996-01-01

    Geothermal investigations were carried out in Nuporanga, state of São Paulo (Brazil), where occurrence of seismic activity has been found to be closely related to opening of groundwater wells. Results of macroseismic studies show that seismic activity had its beginning in May 1977, soon after completion of drilling of the COLABA well and most of the initial seismic events are

  10. Laboratory testing and modeling to evaluate perfluorocarbon compounds as tracers in geothermal systems

    SciTech Connect

    Reimus, Paul W [Los Alamos National Laboratory

    2011-01-21

    The thermal stability and adsorption characteristics of three perfluorinated hydrocarbon compounds were evaluated under geothermal conditions to determine the potential to use these compounds as conservative or thermally-degrading tracers in Engineered (or Enhanced) Geothermal Systems (EGS). The three compounds tested were perfluorodimethyl-cyclobutane (PDCB), perfluoromethylcyclohexane (PMCH), and perfluorotrimethylcyclohexane (PTCH), which are collectively referred to as perfluorinated tracers, or PFTs. Two sets of duplicate tests were conducted in batch mode in gold-bag reactors, with one pair of reactors charged with a synthetic geothermal brine containing the PFTs and a second pair was charged with the brine-PFT mixture plus a mineral assemblage chosen to be representative of activated fractures in an EGS reservoir. A fifth reactor was charged with deionized water containing the three PFTs. The experiments were conducted at {approx}100 bar, with temperatures ranging from 230 C to 300 C. Semi-analytical and numerical modeling was also conducted to show how the PFTs could be used in conjunction with other tracers to interrogate surface area to volume ratios and temperature profiles in EGS reservoirs. Both single-well and cross-hole tracer tests are simulated to illustrate how different suites of tracers could be used to accomplish these objectives. The single-well tests are especially attractive for EGS applications because they allow the effectiveness of a stimulation to be evaluated without drilling a second well.

  11. Geobotanical characterization of a geothermal system using hyperspectral imagery: Long Valley Caldera, CA

    SciTech Connect

    Carter, M R; Cochran, S A; Martini, B A; Pickles, W L; Potts, D C; Priest, R E; Silver, E A; Wayne, B A; White, W T

    1998-12-01

    We have analyzed hyperspectral Airborne Visible-Infrared Imaging System (AVIRIS) imagery taken in September of 1992 in Long Valley Caldera, CA, a geothermally active region expressed surficially by hot springs and fumaroles. Geological and vegetation mapping are attempted through spectral classification of imagery. Particular hot spring areas in the caldera are targeted for analysis. The data is analyzed for unique geobotanical patterns in the vicinity of hot springs as well as gross identification of dominant plant and mineral species. Spectra used for the classifications come from a vegetation spectral library created for plant species found to be associated with geothermal processes. This library takes into account the seasonality of vegetation by including spectra for species on a monthly basis. Geological spectra are taken from JPL and USGS mineral libraries. Preliminary classifications of hot spring areas indicate some success in mineral identification and less successful vegetation species identification. The small spatial extent of individual plants demands either sub-pixel analysis or increased spatial resolution of imagery. Future work will also include preliminary analysis of a hyperspectral thermal imagery dataset and a multitemporal air photo dataset. The combination of these remotely sensed datasets for Long Valley will yield a valuable product for geothermal exploration efforts in other regions.

  12. Enhanced Geothermal Systems (EGS) well construction technology evaluation report.

    SciTech Connect

    Capuano, Louis, Jr. (Thermasource Inc.); Huh, Michael; Swanson, Robert (Thermasource Inc.); Raymond, David Wayne; Finger, John Travis; Mansure, Arthur James; Polsky, Yarom; Knudsen, Steven Dell

    2008-12-01

    Electricity production from geothermal resources is currently based on the exploitation of hydrothermal reservoirs. Hydrothermal reservoirs possess three ingredients critical to present day commercial extraction of subsurface heat: high temperature, in-situ fluid and high permeability. Relative to the total subsurface heat resource available, hydrothermal resources are geographically and quantitatively limited. A 2006 DOE sponsored study led by MIT entitled 'The Future of Geothermal Energy' estimates the thermal resource underlying the United States at depths between 3 km and 10 km to be on the order of 14 million EJ. For comparison purposes, total U.S. energy consumption in 2005 was 100 EJ. The overwhelming majority of this resource is present in geological formations which lack either in-situ fluid, permeability or both. Economical extraction of the heat in non-hydrothermal situations is termed Enhanced or Engineered Geothermal Systems (EGS). The technologies and processes required for EGS are currently in a developmental stage. Accessing the vast thermal resource between 3 km and 10 km in particular requires a significant extension of current hydrothermal practice, where wells rarely reach 3 km in depth. This report provides an assessment of well construction technology for EGS with two primary objectives: (1) Determining the ability of existing technologies to develop EGS wells. (2) Identifying critical well construction research lines and development technologies that are likely to enhance prospects for EGS viability and improve overall economics. Towards these ends, a methodology is followed in which a case study is developed to systematically and quantitatively evaluate EGS well construction technology needs. A baseline EGS well specification is first formulated. The steps, tasks and tools involved in the construction of this prospective baseline EGS well are then explicitly defined by a geothermal drilling contractor in terms of sequence, time and cost. A task and cost based analysis of the exercise is subsequently conducted to develop a deeper understanding of the key technical and economic drivers of the well construction process. Finally, future research & development recommendations are provided and ranked based on their economic and technical significance.

  13. Outstanding Issues in the Assessment of Enhanced Geothermal Systems Resources

    NASA Astrophysics Data System (ADS)

    Williams, C.; Deangelo, J.

    2010-12-01

    The successful implementation of Enhanced Geothermal Systems (EGS) technology has the potential to dramatically expand both the magnitude and spatial extent of geothermal energy production, and the U.S. Geological Survey (USGS) has been working to develop a comprehensive EGS resource assessment for the United States. However, a number of outstanding scientific and technical issues must be resolved in order to ensure the accuracy and reliability of this assessment. Among these are determining those conditions under which it is possible to replicate the high average permeability (approximately 10-15 to 10-13 m2) characteristic of natural hydrothermal reservoirs, evaluating the likely heterogeneity of fracture permeability within EGS reservoirs and its influence on the geothermal recovery factor, Rg, which is defined as the ratio of produced thermal energy to the thermal energy contained in the stimulated volume comprising the reservoir, and improving estimates of temperature in the upper crust to better quantify the thermal energy available at those depths viable for EGS reservoir creation. Models for the development of fracture permeability from the shear slip along pre-existing natural fractures induced by hydraulic stimulation indicate that production from EGS reservoirs will be sensitive to the influence of effective stress and rock properties on the processes of shear fracture formation and closure. Calibration of model parameters with results from EGS field experiments and demonstration projects suggests that sufficient permeability may be difficult to attain through shear stimulation at depths greater than approximately 6 km, particularly in regions characterized by high normal stress on pre-existing faults and fractures. In addition, the expected heterogeneity of fracture permeability within EGS reservoirs may limit Rg to values on the order of 0.05 to 0.1, which is at the lower end of the observed range for producing natural geothermal reservoirs. Although there are significant gaps in the spatial coverage of heat flow measurements in much of the United States and some uncertainty in the estimation of thermal properties at depth, analysis of the existing thermal data indicates that even with the possible constraints outlined above, large areas of the western United States will be suitable for EGS development. However, this provisional interpretation is compromised by the limited number of cases in which model predictions can be compared to laboratory or in situ data. The key challenge for improved EGS resource assessments is acquiring and interpreting comprehensive laboratory and field data that can provide quantitative constraints on the recovery of heat from EGS reservoirs in diverse settings.

  14. Boiling and fluid mixing in the chlorite zone of the Larderello geothermal system

    Microsoft Academic Search

    Giovanni Ruggieri; Michel Cathelineau; Marie-Christine Boiron; Christian Marignac

    1999-01-01

    The geochemical features of the geothermal fluids produced within the boiling zone in the relatively shallow parts of the Larderello geothermal system (Italy) have been documented as a result of deep drilling which provided samples from 1480 to 2500 m depth. Four wells (Monteverdi 1, Monteverdi 2A, Sasso 22 and Capannoli 2B) have been sampled in the intermediate parts of

  15. Characterization of geothermal systems in volcano-tectonic depressions : Japan and New Zealand

    Microsoft Academic Search

    Shiro Tamanyu; C. Peter Wood

    Characterization of geothermal systems was investigated in two regional scale volcano- tectonic depressions, the Kuju-Beppu Graben (KBG), in Japan, and the young-Taupo Volcanic Zone (TVZ) in New Zealand. The distribution patterns of geothermal fields are different. In the KBG they are restricted to areas on and behind only the youngest volcanic front, but are evenly spaced through- out the whole

  16. Modeling Self-Potential Effects During Reservoir Stimulation in Enhanced Geothermal Systems.

    NASA Astrophysics Data System (ADS)

    Troiano, Antonio; Giulia Di Giuseppe, Maria; Monetti, Alessio; Patella, Domenico; Troise, Claudia; De Natale, Giuseppe

    2015-04-01

    Geothermal systems represent a large resource that can provide, with a reasonable investment, a very high and cost-effective power generating capacity. Considering also the very low environmental impact, their development represents, in the next decades, an enormous perspective. Despite its unquestionable potential, geothermal exploitation has long been perceived as limited, mainly because of the dependence from strict site-related conditions, mainly related to the reservoir rock's permeability and to the high thermal gradient, implying the presence of large amounts of hot fluids at reasonable depth. Many of such limitations can be overcome using Enhanced Geothermal Systems technology (EGS), where massive fluid injection is performed to increase the rock permeability by fracturing. This is a powerful method to exploit hot rocks with low natural permeability, otherwise not exploitable. Numerical procedures have already been presented in literature reproducing thermodynamic evolution and stress changes of systems where fluids are injected. However, stimulated fluid flow in geothermal reservoirs can produce also surface Self-Potential (SP) anomalies of several mV. A commonly accepted interpretation involves the activation of electrokinetic processes. Since the induced seismicity risk is generally correlated to fluid circulation stimulated in an area exceeding the well of several hundreds of meters, the wellbore pressure values can be totally uncorrelated to seismic hazard. However, SP anomalies, being generated from pressure gradients in the whole area where fluids flow, has an interesting potential as induced earthquake precursor. In this work, SP anomalies observed above the Soultz-sous-Forets (Alsace, France) geothermal reservoir while injecting cold water have been modeled, considering a source related to the fluid flow induced by the well stimulation process. In particular, the retrieved changes of pressure due to well stimulation in the EGS system have been used as a source term, to evaluate the electric currents generating the potential anomalies. In such a way, SP anomalies generated during the stimulation process at Soultz-sous-Forets have been simulated in order to evaluate the effectiveness of SP monitoring to mitigate the induced seismicity risk.

  17. Geochemical exploration of a promissory Enhanced Geothermal System (EGS): the Acoculco caldera, Mexico.

    NASA Astrophysics Data System (ADS)

    Peiffer, Loic; Romero, Ruben Bernard; Pérez-Zarate, Daniel; Guevara, Mirna; Santoyo Gutiérrez, Edgar

    2014-05-01

    The Acoculco caldera (Puebla, Mexico) has been identified by the Mexican Federal Electricity Company (in Spanish 'Comisión Federal de Electricidad', CFE) as a potential Enhanced Geothermal System (EGS) candidate. Two exploration wells were drilled and promising temperatures of ~300° C have been measured at a depth of 2000 m with a geothermal gradient of 11oC/100m, which is three times higher than the baseline gradient measured within the Trans-Mexican Volcanic Belt. As usually observed in Hot Dry Rock systems, thermal manifestations in surface are scarce and consist in low-temperature bubbling springs and soil degassing. The goals of this study were to identify the origin of these fluids, to estimate the soil degassing rate and to explore new areas for a future detailed exploration and drilling activities. Water and gas samples were collected for chemical and isotopic analysis (?18O, ?D, 3He/4He, 13C, 15N) and a multi-gas (CO2, CH4, H2S) soil survey was carried out using the accumulation chamber method. Springs' compositions indicate a meteoric origin and the dissolution of CO2 and H2S-rich gases, while gas compositions reveal a MORB-type origin mixed with some arc-type contribution. Gas geothermometry results are similar to temperatures measured during well drilling (260° C-300° C). Amongst all measured CO2 fluxes, only 5% (mean: 5543 g m-2 day-1) show typical geothermal values, while the remaining fluxes are low and correspond to biogenic degassing (mean: 18 g m-2 day-1). The low degassing rate of the geothermal system is a consequence of the intense hydrothermal alteration observed in the upper 800 m of the system which acts as an impermeable caprock. Highest measured CO2 fluxes (above > 600 g m-2 day-1) have corresponding CH4/CO2 flux ratios similar to mass ratios of sampled gases, which suggest an advective fluid transport. To represent field conditions, a numerical model was also applied to simulate the migration of CO2 towards the surface through a shallow aquifer under fully saturated conditions. By changing some of the aquifer properties (i.e., depth, permeability and porosity), it was found how geothermal CO2 fluxes can show values similar to a biogenic background flux. Future field work at Acoculco will include ?13C analysis together with soil flux measurements for a better discrimination of the degassing origin, and a thinner flux measurement grid will be defined for a better detection of any possible gas flux anomaly.

  18. Screening for heat transport by groundwater in closed geothermal systems.

    PubMed

    Ferguson, Grant

    2015-05-01

    Heat transfer due to groundwater flow can significantly affect closed geothermal systems. Here, a screening method is developed, based on Peclet numbers for these systems and Darcy's law. Conduction-only conditions should not be expected where specific discharges exceed 10(-8) ?m/s. Constraints on hydraulic gradients allow for preliminary screening for advection based on rock or soil types. Identification of materials with very low hydraulic conductivity, such as shale and intact igneous and metamorphic rock, allow for analysis with considering conduction only. Variability in known hydraulic conductivity allows for the possibility of advection in most other rocks and soil types. Further screening relies on refinement of estimates of hydraulic gradients and hydraulic conductivity through site investigations and modeling until the presence or absence of conduction can be confirmed. PMID:24438345

  19. Thermal and chemical evolution of The Geysers geothermal system, California

    SciTech Connect

    Moore, J.N.

    1992-01-01

    Fluid inclusions and mineral assemblages provide a reward of the thermal and chemical changes that occurred during the evolution of The Geysers geothermal system. The data document the presence of an extensive liquid dominated geothermal system that developed in response to felsite intrusion and its evolution to a vapor-dominated regime. Temperatures within the early liquid-dominated system ranged from 175 C at a distance of 7200 feet from the felsite to more than 350 C near the contact while salinities varied from 5 equivalent weight percent NaCl (at a distance of 5500 feet) to more than 26 weight percent NaCl. As temperatures around the felsite declined, the liquid-dominated system collapsed upon itself. Downward migration of the low salinity waters resulted in dilution of the fluids present in regions now occupied by the caprock and normal vapor-dominated reservoir. In contrast, dilution was minor in rocks now hosting the high-temperature vapor-dominated reservoir. This suggests that low permeabilities are the primary reason for the development of the high-temperature reservoir. Boiling within the caprock produced late-stage veins of calcite and quartz. As the fluid boiled off, condensate was trapped as low salinity fluid inclusions. Within the main body of the reservoir, a liquid phase with salinities of up to 7 equivalent weight percent NaCl persisted to temperatures between 250 and 270 C. However, except for the presence of vapor-rich inclusions, little evidence of boiling within the reservoir rocks was preserved.

  20. Geothermal Energy.

    ERIC Educational Resources Information Center

    Nemzer, Marilyn; Page, Deborah

    This curriculum unit describes geothermal energy in the context of the world's energy needs. It addresses renewable and nonrenewable energy sources with an in-depth study of geothermal energy--its geology, its history, and its many uses. Included are integrated activities involving science, as well as math, social studies, and language arts.…

  1. Life-cycle analysis results of geothermal systems in comparison to other power systems.

    SciTech Connect

    Sullivan, J. L.; Clark, C. E.; Han, J.; Wang, M.; Energy Systems

    2010-10-11

    A life-cycle energy and greenhouse gas emissions analysis has been conducted with Argonne National Laboratory's expanded Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model for geothermal power-generating technologies, including enhanced geothermal, hydrothermal flash, and hydrothermal binary technologies. As a basis of comparison, a similar analysis has been conducted for other power-generating systems, including coal, natural gas combined cycle, nuclear, hydroelectric, wind, photovoltaic, and biomass by expanding the GREET model to include power plant construction for these latter systems with literature data. In this way, the GREET model has been expanded to include plant construction, as well as the usual fuel production and consumption stages of power plant life cycles. For the plant construction phase, on a per-megawatt (MW) output basis, conventional power plants in general are found to require less steel and concrete than renewable power systems. With the exception of the concrete requirements for gravity dam hydroelectric, enhanced geothermal and hydrothermal binary used more of these materials per MW than other renewable power-generation systems. Energy and greenhouse gas (GHG) ratios for the infrastructure and other life-cycle stages have also been developed in this study per kilowatt-hour (kWh) of electricity output by taking into account both plant capacity and plant lifetime. Generally, energy burdens per energy output associated with plant infrastructure are higher for renewable systems than conventional ones. GHG emissions per kWh of electricity output for plant construction follow a similar trend. Although some of the renewable systems have GHG emissions during plant operation, they are much smaller than those emitted by fossil fuel thermoelectric systems. Binary geothermal systems have virtually insignificant GHG emissions compared to fossil systems. Taking into account plant construction and operation, the GREET model shows that fossil thermal plants have fossil energy use and GHG emissions per kWh of electricity output about one order of magnitude higher than renewable power systems, including geothermal power.

  2. Federal Geothermal Research Program Update Fiscal Year 2004

    SciTech Connect

    Not Available

    2005-03-01

    The Department of Energy (DOE) and its predecessors have conducted research and development (R&D) in geothermal energy since 1971. The Geothermal Technologies Program (GTP) works in partnership with industry to establish geothermal energy as an economically competitive contributor to the U.S. energy supply. Geothermal energy production, a $1.5 billion a year industry, generates electricity or provides heat for direct use applications. The technologies developed by the Geothermal Technologies Program will provide the Nation with new sources of electricity that are highly reliable and cost competitive and do not add to America's air pollution or the emission of greenhouse gases. Geothermal electricity generation is not subject to fuel price volatility and supply disruptions from changes in global energy markets. Geothermal energy systems use a domestic and renewable source of energy. The Geothermal Technologies Program develops innovative technologies to find, access, and use the Nation's geothermal resources. These efforts include emphasis on Enhanced Geothermal Systems (EGS) with continued R&D on geophysical and geochemical exploration technologies, improved drilling systems, and more efficient heat exchangers and condensers. The Geothermal Technologies Program is balanced between short-term goals of greater interest to industry, and long-term goals of importance to national energy interests. The program's research and development activities are expected to increase the number of new domestic geothermal fields, increase the success rate of geothermal well drilling, and reduce the costs of constructing and operating geothermal power plants. These improvements will increase the quantity of economically viable geothermal resources, leading in turn to an increased number of geothermal power facilities serving more energy demand. These new geothermal projects will take advantage of geothermal resources in locations where development is not currently possible or economical.

  3. Federal Geothermal Research Program Update - Fiscal Year 2004

    SciTech Connect

    Patrick Laney

    2005-03-01

    The Department of Energy (DOE) and its predecessors have conducted research and development (R&D) in geothermal energy since 1971. The Geothermal Technologies Program (GTP) works in partnership with industry to establish geothermal energy as an economically competitive contributor to the U.S. energy supply. Geothermal energy production, a $1.5 billion a year industry, generates electricity or provides heat for direct use applications. The technologies developed by the Geothermal Technologies Program will provide the Nation with new sources of electricity that are highly reliable and cost competitive and do not add to America's air pollution or the emission of greenhouse gases. Geothermal electricity generation is not subject to fuel price volatility and supply disruptions from changes in global energy markets. Geothermal energy systems use a domestic and renewable source of energy. The Geothermal Technologies Program develops innovative technologies to find, access, and use the Nation's geothermal resources. These efforts include emphasis on Enhanced Geothermal Systems (EGS) with continued R&D on geophysical and geochemical exploration technologies, improved drilling systems, and more efficient heat exchangers and condensers. The Geothermal Technologies Program is balanced between short-term goals of greater interest to industry, and long-term goals of importance to national energy interests. The program's research and development activities are expected to increase the number of new domestic geothermal fields, increase the success rate of geothermal well drilling, and reduce the costs of constructing and operating geothermal power plants. These improvements will increase the quantity of economically viable geothermal resources, leading in turn to an increased number of geothermal power facilities serving more energy demand. These new geothermal projects will take advantage of geothermal resources in locations where development is not currently possible or economical.

  4. Geothermal Case Studies

    SciTech Connect

    Young, Katherine

    2014-09-30

    The US Geological Survey (USGS) resource assessment (Williams et al., 2009) outlined a mean 30GWe of undiscovered hydrothermal resource in the western US. One goal of the Geothermal Technologies Office (GTO) is to accelerate the development of this undiscovered resource. The Geothermal Technologies Program (GTP) Blue Ribbon Panel (GTO, 2011) recommended that DOE focus efforts on helping industry identify hidden geothermal resources to increase geothermal capacity in the near term. Increased exploration activity will produce more prospects, more discoveries, and more readily developable resources. Detailed exploration case studies akin to those found in oil and gas (e.g. Beaumont, et al, 1990) will give operators a single point of information to gather clean, unbiased information on which to build geothermal drilling prospects. To support this effort, the National Renewable Energy laboratory (NREL) has been working with the Department of Energy (DOE) to develop a template for geothermal case studies on the Geothermal Gateway on OpenEI. In fiscal year 2013, the template was developed and tested with two case studies: Raft River Geothermal Area (http://en.openei.org/wiki/Raft_River_Geothermal_Area) and Coso Geothermal Area (http://en.openei.org/wiki/Coso_Geothermal_Area). In fiscal year 2014, ten additional case studies were completed, and additional features were added to the template to allow for more data and the direct citations of data. The template allows for: Data - a variety of data can be collected for each area, including power production information, well field information, geologic information, reservoir information, and geochemistry information. Narratives ? general (e.g. area overview, history and infrastructure), technical (e.g. exploration history, well field description, R&D activities) and geologic narratives (e.g. area geology, hydrothermal system, heat source, geochemistry.) Exploration Activity Catalog - catalog of exploration activities conducted in the area (with dates and references.) NEPA Analysis ? a query of NEPA analyses conducted in the area (that have been catalogued in the OpenEI NEPA database.) In fiscal year 2015, NREL is working with universities to populate additional case studies on OpenEI. The goal is to provide a large enough dataset to start conducting analyses of exploration programs to identify correlations between successful exploration plans for areas with similar geologic occurrence models.

  5. Application of TOUGHREACT to performance evaluations of geothermal heat pump systems

    Microsoft Academic Search

    Yongkoo Seol; Kang-Kun Lee

    2007-01-01

    Numerical simulations were performed with a non-isothermal multi-phase reactive geochemical transport code, TOUGHREACT for\\u000a predicting changes in temperature, permeability, porosity, and injectivity resulting from a long term operation of a geothermal\\u000a heat-pump (GHP) system. A one-dimensional model was developed to simulate a GHP system for a potential geothermal reservoir\\u000a with down-hole water temperature of 200°C. The GHP system was developed

  6. The LBL geothermal reservoir technology program

    SciTech Connect

    Lippmann, M.J.

    1991-03-01

    The main objective of the DOE/GD-funded Geothermal Reservoir Technology Program at Lawrence Berkeley Laboratory is the development and testing of new and improved methods and tools needed by industry in its effort to delineate, characterize, evaluate, and exploit hydrothermal systems for geothermal energy. This paper summarizes the recent and ongoing field, laboratory, and theoretical research activities being conducted as part of the Geothermal Reservoir Technology Program. 28 refs., 4 figs.

  7. The geothermal program at Lawrence Berkeley Laboratory

    SciTech Connect

    Lippmann, M.J.

    1987-06-01

    The main purpose of the geothermal program at Lawrence Berkeley Laboratory is to develop, improve and validate methods and instrumentation to: (1) determine geothermal reservoir parameters; (2) detect and characterize reservoir fractures and boundaries; and (3) identify and evaluate the importance of reservoir processes. The ultimate objective of the program, which includes field, theoretical and modeling activities, is to advance the state-of-the-art for characterizing geothermal systems and evaluating their productive capacity and longevity under commercial exploitation.

  8. Coniform stromatolites from geothermal systems, North Island, New Zealand

    USGS Publications Warehouse

    Jones, B.; Renaut, R.W.; Rosen, Michael R.; Ansdell, K.M.

    2002-01-01

    Coniform stromatolites are found in several sites in the Tokaanu and Whakarewarewa geothermal areas of North Island, New Zealand. At Tokaanu, silicification of these stromatolites is taking place in Kirihoro, a shallow hot springfed pool. At Whakarewarewa, subfossil silicified coniform stromatolites are found on the floor of "Waikite Pool" on the discharge apron below Waikite Geyser, and in an old sinter succession at Te Anarata. The microbes in the coniform stromatolites from Tokaanu, Waikite Pool, and Te Anarata have been well preserved through rapid silicification. Nevertheless, subtle differences in the silicification style induced morphological variations that commonly mask or alter morphological features needed for identification of the microbes in terms of extant taxa. The coniform stromatolites in the New Zealand hotspring pools are distinctive because (1) they are formed of upward tapering (i.e., conical) columns, (2) neighboring columns commonly are linked by vertical sheets or bridges, (3) internally, they are formed of alternating high- and low-porosity laminae that have a conical vertical profile, and (4) Phormidium form more than 90% of the biota. As such, they are comparable to modern coniform mats and stromatolites found in the geothermal systems of Yellowstone National Park and ice-covered lakes in Antarctica. Formation of the coniform stromatolites is restricted to pools that are characterized by low current energy and a microflora that is dominated by Phormidium. These delicate and intricate stromatolites could not form in areas characterized by fast flowing water or a diverse microflora. Thus, it appears that the distribution of these distinctive stromatolites is controlled by biological constraints that are superimposed on environmental needs.

  9. Characterization of hot dry rock geothermal energy extraction systems

    NASA Astrophysics Data System (ADS)

    Albright, J. N.; Newton, C. A.

    1981-04-01

    The engineering of heat exchange systems by which geothermal heat can be efficiently extracted from hot impermeable rocks is studied. The system currently under investigation at Fenton Hill, New Mexico consists of a network of large fractures created through the hydraulic pressurization of a well penetrating hot basement rocks and subsequently intersected by a second well drilled to form a flow-thru system. Cool water pumped into the fractures through one well, once heated in the reservoir, returns to the surface through the second well, is cooled, and then recirculated. While much is known about the performance parameters of the fracture network from short-term flow tests, little is understood concerning the spatial dimensions and geometrical relationship of individual fractures comprising the network. Ultimately, the success one has in estimating the long-term performance of such a system where commercialization is an issue, and in engineering future systems with optimal performance, depends on the success in characterizing the flow-thru fracture networks.

  10. National Geothermal Data System: Case Studies on Exploration and Development of Potential Geothermal Sites Through Distributed Data Sharing

    SciTech Connect

    Anderson, Arlene [DOE Geothermal Technologies Office; Allison, Lee [Executive Office of the State of Arizona (Arizona Geological Survey); Richard, Steve [Executive Office of the State of Arizona (Arizona Geological Survey); Caudill-Daugherty, Christy [Executive Office of the State of Arizona (Arizona Geological Survey); Patten, Kim [Executive Office of the State of Arizona (Arizona Geological Survey)

    2014-09-29

    The NGDS released version 1 of the system on April 30, 2014 using the US Geoscience Information Network (USGIN) as its data integration platform. NGDS supports the 2013 Open Data Policy, and as such, the launch was featured at the 2014 Energy Datapalooza. Currently, the NGDS features a comprehensive user interface for searching and accessing nearly 41,000 documents and more than 9 million data points shared by scores of data providers across the U.S. The NGDS supports distributed data sharing, permitting the data owners to maintain the raw data that is made available to the consumer. Researchers and industry have been utilizing the NGDS as a mechanism for promoting geothermal development across the country, from hydrothermal to ground source heat pump applications. Case studies in geothermal research and exploration from across the country are highlighted.

  11. The Earth-Coupled or Geothermal Heat Pump Air Conditioning System

    E-print Network

    Wagers, H. L.; Wagers, M. C.

    1985-01-01

    " and next at proper home insulation, window coverings, etc. The other electrical appliances in the home use relatively minor amounts of electricity compared to the air conditioning and hot water heating system. This paper will describe the geothermal heat...

  12. Hydrothermal spallation drilling and advanced energy conversion technologies for Engineered Geothermal Systems

    E-print Network

    Augustine, Chad R

    2009-01-01

    The purpose of this research was to study the various factors affecting the economic and technical feasibility of Engineered Geothermal Systems, with a special emphasis on advanced drilling technologies. The first part of ...

  13. Design, fabrication, delivery, operation and maintenance of a geothermal power conversion system

    NASA Astrophysics Data System (ADS)

    1980-12-01

    The design, fabrication, delivery, operation and maintenance of an Hydrothermal Power Company 1250 KVA geothermal power conversion system using a helical screw expander as the prime mover is described. Hydrostatic and acceptance testing are discussed.

  14. Method for inhibiting silica precipitation and scaling in geothermal flow systems

    DOEpatents

    Harrar, J.E.; Lorensen, L.E.; Locke, F.E.

    1980-06-13

    A method for inhibiting silica scaling and precipitation in geothermal flow systems by on-line injection of low concentrations of cationic nitrogen-containing compounds, particularly polymeric imines, polymeric amines, and quaternary ammonium compounds is described.

  15. Method for inhibiting silica precipitation and scaling in geothermal flow systems

    DOEpatents

    Harrar, Jackson E. (Castro Valley, CA); Lorensen, Lyman E. (Orinda, CA); Locke, Frank E. (Lafayette, CA)

    1982-01-01

    A method for inhibiting silica scaling and precipitation in geothermal flow systems by on-line injection of low concentrations of cationic nitrogen-containing compounds, particularly polymeric imines, polymeric amines, and quaternary ammonium compounds.

  16. Design, fabrication, delivery, operation and maintenance of a geothermal power conversion system

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The design, fabrication, delivery, operation and maintenance of an Hydrothermal Power Company 1250 KVA geothermal power conversion system using a helical screw expander as the prime mover is described. Hydrostatic and acceptance testing are discussed.

  17. Importance of Hydrogeological Conditions on Open-loop Geothermal System

    NASA Astrophysics Data System (ADS)

    Park, D.; Bae, G.; Kim, S.; Lee, K.

    2013-12-01

    The open-loop geothermal system has been known as an eco-friendly, energy-saving, and cost-efficient alternative for the cooling and heating of buildings with directly using the relatively stable temperature of groundwater. Thus, hydrogeological properties of aquifer, such as hydraulic conductivity and storage, must be important in the system application. The study site is located near Han-river, Korea, and because of the well-developed alluvium it might be a typical site appropriate to this system requiring an amount of groundwater. In this study, the first objective of numerical experiments was to find the best distributions of pumping and injection wells suitable to the hydrogeological conditions of the site for the efficient and sustainable system operation. The aquifer has a gravel layer at 15m depth below the ground surface and the river and the agricultural field, which may be a potential contaminant source, are located at the west and east sides, respectively. Under the general conditions that the regional groundwater flows from the east to the river, the locally reversed well distribution, locating the pumping well at upgradient and the injection well at downgradient of the regional flow, was most sustainable. The gravel layer with high hydraulic conductivity caused a little drawdown despite of an amount of pumping and allowed to stably reinject the used groundwater in all the cases, but it provided a passage transferring the injected heat to the pumping well quickly, particularly in the cases locating the injection well at the upgradient. This thermal interference was more severe in the cases of the short distance between the wells. The high conductive layer is also a reason that the seasonal role conversion of wells for the aquifer thermal energy storage was ineffective in this site. Furthermore, the well distribution vertical to the regional groundwater flow was stable, but not best, and, thus, it may be a good choice in the conditions that the regional groundwater flow direction has often been changed. Any effects of the seasonal river temperature variation and contaminant sources were not found on the wells because of the well screen installed at only the relatively deep gravel layer. Finally, it was evaluated whether if these results are valid in a homogeneous aquifer with the full screen of wells and the aquifer having a sediment layer with high hydraulic conductivity at a shallow depth, which are also typical aquifers near river. All the results concluded that it is essential to investigate and understand the site-specific hydrogeological conditions for the successful application of open-loop geothermal system.

  18. Earthquakes, active faults, and geothermal areas in the imperial valley, california.

    PubMed

    Hill, D P; Mowinckel, P; Peake, L G

    1975-06-27

    A dense seismograph network in the Imperial Valley recorded a series of earthquake swarms along the Imperial and Brawley faults and a diffuse pattern of earthquakes along the San Jacinto fault. Two known geothermal areas are closely associated with these earthquake swarms. This seismicity pattern demonstrates that seismic slip is occurring along both the Imperial-Brawley and San Jacinto fault systems. PMID:17772600

  19. Systems study of drilling for installation of geothermal heat pumps

    SciTech Connect

    Finger, J.T.; Sullivan, W.N.; Jacobson, R.D.; Pierce, K.G.

    1997-09-01

    Geothermal, or ground-source, heat pumps (GHP) are much more efficient than air-source units such as conventional air conditioners. A major obstacle to their use is the relatively high initial cost of installing the heat-exchange loops into the ground. In an effort to identify drivers which influence installation cost, a number of site visits were made during 1996 to assess the state-of-the-art in drilling for GHP loop installation. As an aid to quantifying the effect of various drilling-process improvements, we constructed a spread-sheet based on estimated time and material costs for all the activities required in a typical loop-field installation. By substituting different (improved) values into specific activity costs, the effect on total project costs can be easily seen. This report contains brief descriptions of the site visits, key points learned during the visits, copies of the spread-sheet, recommendations for further work, and sample results from sensitivity analysis using the spread-sheet.

  20. Experience with the EM60 electromagnetic system for geothermal exploration in Nevada

    Microsoft Academic Search

    M. Wilt; N. E. Goldstein; M. Stark; J. R. Haught; H. F. Morrison

    1981-01-01

    Lawrence Berkeley Laboratory (LBL) conducted controlled-source electromagnetic (EM) surveys at three geothermal prospects in northern Nevada. Over 40 soundings were made in Panther Canyon (Grass Valley), near Winnemucca; Soda Lakes, near Fallon; and McCoy, west of Austin, to test and demonstrate the applicability of LBL's EM-60 system to geothermal exploration. The EM-60 is a frequency-domain system using three-component magnetic detection.

  1. Geochemical studies of the geothermal systems in Kenya: II. The Majimoto geothermal field

    NASA Astrophysics Data System (ADS)

    Tole, Mwakio P.

    1992-04-01

    The Majimoto geothermal field discharges at the boundary between metamorphic schists and gneisses of Precambrian age, and Pleistocene volcanic ashes. The waters are near neutral, low salinity waters. Calculated reservoir temperatures are about 90°C. Oxygen and hydrogen isotopes indicate that the thermal waters are meteoric in origin. The field is suitable for development for uses in spa therapy, crop drying, milk pasteurisation, leather processing and house warming.

  2. Enhanced Geothermal Systems (EGS) R&D Program: Monitoring EGS-Related Research

    SciTech Connect

    McLarty, Lynn; Entingh, Daniel; Carwile, Clifton

    2000-09-29

    This report reviews technologies that could be applicable to Enhanced Geothermal Systems development. EGS covers the spectrum of geothermal resources from hydrothermal to hot dry rock. We monitored recent and ongoing research, as reported in the technical literature, that would be useful in expanding current and future geothermal fields. The literature review was supplemented by input obtained through contacts with researchers throughout the United States. Technologies are emerging that have exceptional promise for finding fractures in nonhomogeneous rock, especially during and after episodes of stimulation to enhance natural permeability.

  3. Enhanced Geothermal System Development of the AmeriCulture Leasehold in the Animas Valley

    SciTech Connect

    Duchane, David V; Seawright, Gary L; Sewright, Damon E; Brown, Don; Witcher, James c.; Nichols, Kenneth E.

    2001-03-02

    Working under the grant with AmeriCulture, Inc., and its team of geothermal experts, assembled a plan to apply enhanced geothermal systems (EGS) techniques to increase both the temperature and flow rate of the geothermal waters on its leasehold. AmeriCulture operates a commercial aquaculture facility that will benefit from the larger quantities of thermal energy and low cost electric power that EGS technology can provide. The project brought together a team of specialists that, as a group, provided the full range of expertise required to successfully develop and implement the project.

  4. New Mexican geothermal development

    SciTech Connect

    Gerard, V.

    1987-06-01

    New Mexico has more than 300 known thermal springs and wells, most located within the Rio Grande Rift, a north-south trending geological system that runs through the state. In the 1970's, state and federal governments took an active interest in geothermal energy in New Mexico. The studies identified 21 low-temperature sites in the state with the highest potential for commercial development. In 1980, the state initiated the Geothermal Commercialization Program. The program's goal is to promote the use of geothermal energy for economic development. The primary target is the sector of the commercial greenhouse industry growing high-value horticultural and floricultural crops. New Mexico State University (NMSU) has become the center of the state's geothermal research program. The NMSU Geothermal Greenhouse Facility, constructed and operated by the New Mexico Solar Energy Institute, is a 12,000-square-foot, geothermally-heated greenhouse that provides a testing facility for commercial growers considering southern New Mexico for their operations. By 1985, the state's geothermal greenhouse industry covered 13 acres. Since the NMSU greenhouses were constructed in 1986, two large greenhouse companies have taken advantage of the facilities. Flores de New Mexico, of Las Cruces, and Masson Southwest, Inc. of Linwood, Kansas, used the facilities for pilot studies of the area. Both have stayed in the area and have expanded. Flores de New Mexico built 10 acres of greenhouses on the NMSU campus and is planning a five-acre expansion, and Masson, Inc. is building a four-acre greenhouse in Radium Springs, NM. Geothermal technology is also being used by three greenhouse businesses in Hidalgo County's Animas Valley, south of Lordsburg. Beall Company of New Mexico, Inc., Burgett Floral, Inc., and McCant's Greenhouse are tapping into the large thermal reservoir in the southwestern corner of the state.

  5. Chemistry of gases associated with geothermal activity and volcanism in Iceland: A review

    NASA Astrophysics Data System (ADS)

    Arnórsson, StefáN.

    1986-11-01

    The concentrations of CO2, H2S, and H2 in geothermal reservoir fluids in Iceland are fixed by equilibria with alteration minerals. CH4 concentrations are typically very low, and gas-gas equilibria involving CO2, H2, and CH4 are generally not closely approached. In some geothermal systems the N2 is atmospheric only, but a magmatic N2 contribution is significant in others. N2/Ar ratios lie mostly between that of the atmosphere (85) and the N2/Ar ratio in cold water in contact with the atmosphere (37). Fluids with a strong magmatic N2 contribution have N2/Ar ratios of 40-60. During several volcanic eruptions in Iceland, magmatic gases have emerged at the surface beyond the eruptive vents and mixed with surrounding groundwaters. CO and H2 can be detected closest to the vent, but only CO2 is detected at greater distances. During the present volcanic episode at Krafla, fugitive constituents have been transported into the geothermal reservoir from the underlying magma chamber. Probably most of the carbon and sulphur in altered rocks of high-temperature geothermal systems have been derived from degassing magma bodies.

  6. Technical support for geopressured-geothermal well activities in Louisiana. Annual report, 1 November 1982-31 October 1983

    SciTech Connect

    Not Available

    1984-10-31

    This annual report describes environmental monitoring of microseismic activity, land-surface elevations, and surface and ground-water quality at three designed geopressured-geothermal test well sites in Louisiana.

  7. Technical support for geopressured-geothermal well activities in Louisiana. Final report, 1 November 1983-31 October 1984

    SciTech Connect

    Not Available

    1985-12-01

    This report describes environmental monitoring of microseismic activity, land-surface subsidence, and surface and ground-water quality at three designed geopressured-geothermal test well sites in Louisiana. Separate abstracts have been prepared for individual sections. (ACR)

  8. Gas and water geochemistry of geothermal systems in Dominica, Lesser Antilles island arc

    NASA Astrophysics Data System (ADS)

    Joseph, Erouscilla P.; Fournier, Nicolas; Lindsay, Jan M.; Fischer, Tobias P.

    2011-09-01

    Four of the nine potentially active volcanoes on the island of Dominica in the Lesser Antilles volcanic island arc have associated active volcanic-hydrothermal systems. Between 2000 and 2006 the gas and thermal waters from these systems were investigated to geochemically characterise the fluids, gain insight into the temperature and equilibrium state of the underlying reservoirs, and evaluate the feasibility of monitoring geothermal features as a volcano surveillance tool in Dominica. The geothermal gases are typical of those found in arc-type settings, with N 2 excess and low amounts of He and Ar. The dry gas is dominated by CO 2 (ranging from 492 to 993 mmol/mol), and has a hydrothermal signature with hydrogen sulphide as the main sulphurous gas. The waters are predominantly acid-sulphate (SO 4 = 100-4200 mg/L, pH ? 4), and likely formed as a result of dilution of acidic gases in near surface oxygenated groundwater. Enrichment in both ? 18O and ?D with respect to the global meteoric water line (GMWL) confirms that the waters are of primarily meteoric origin, but have been affected by evaporation processes. Quartz geothermometers gave equilibrium temperatures of 83 °C-203 °C. These temperatures contrast with the higher equilibrium temperature ranges (170 °C-350 °C) obtained for the gases using the H 2/Ar*-CH 4/CO 2 gas ratios plot, suggesting that the quartz geothermometers are affected by non-attainment of equilibrium. This may be a result of precipitation of the dissolved silica and/or dilution by relatively cold shallow aquifers of the thermal fluids. Generally, no significant variations in fluid gas chemistry of the hydrothermal systems were observed during the study period, and we propose that there were no changes in the state of volcanic activity in this period. One exception to this occurred in a feature known as the Boiling Lake, which underwent a month-long period of significant compositional, temperature and water level fluctuations ascribed to a drastic decrease of hydrothermal input related to a perturbation in the lake (probably seismically induced). This geochemical study is part of an ongoing monitoring programme of Dominica geothermal systems, aimed at establishing long-term geochemical observations for the purpose of volcano monitoring.

  9. Preliminary assessment of the geothermal system of the Tiris volcanic area, East Java, Indonesia.

    NASA Astrophysics Data System (ADS)

    Deon, F.; Moeck, I.; Sheytt, T.; Jaya, M. S.

    2012-04-01

    Indonesia, with 15 % of the world's active volcanoes, hosts a total estimated geothermal potential of 27000 MW of which 1197 MWe in 2011 have been installed. Exploration of magmatic remote areas is therefore important. Our investigation area is located at the volcano Lamongan, Tiris East Java, Indonesia, which is part of the modern Sunda Arc Region, characterized by extensional regime. The average ground water temperature in the area ranges between 27 and 29 ° C and the warm springs between 35 - 45 ° C, evidencing a geothermal potential of the area. Numerous maars and cindered cones have been located and studied here, some of them with a NW - SE lineament similar to the Tiris fault (only observed in satellite images). In this first exploration stage we characterized the geochemistry of the springs and investigated the petrology of the rocks. They were analyzed in terms of mineral composition (optical microscopy and electron microprobe) and major element composition (X-ray fluorescence). The samples have a typical basaltic - basaltic andesite composition, with abundant plagioclase with An65 up to An90, as well as olivine and pyroxene. The plagioclase crystals are several mm large, twinned and show no hydrothermal alteration. The fluid chemistry was determined in term of cation and anion concentration with Inductively Coupled Plasma Mass Spectrometry. The chemistry of geothermal waters provides specific information about the deep of the fluids in geothermal system and the discharge location. The concentrations of Na+, Ca2+, Li+, B3+ and Cl- suggest that the water of the Lamongan area derive from sea water intrusions. The high permeable pyroclastites, overlain by lower permeable basalt - andesitic basalt, observed in the field, may have channeled the sea water from the coast to the Tiris area. A structural lineament, NW - SE, may control the water intrusion, as the lineament of the springs confirms. The high HCO3-concentration in the fluid samples, as no carbonate rocks are known in the area, must derive from another source (magma chamber?). The occurrence of pyroclastites overlain by andesite suggests the presence of a concealed layer. This could be responsible for capturing SO42- accounting to the HCO3- excess of the springs, located in the outflow zone of the system. Acknowledgements We thank the German Federal Ministry for Education and Research (BMBF) for funding this German project under the grant 03G0753A. We would also like to thank Iris Pieper for the ICP water analyses at the TU Berlin, and DINAS ESDM, Surabaya, Indonesia for their support in the field campaigns.

  10. Advances in geothermal energy use

    SciTech Connect

    Kilkis, I.B. [Heatway Radiant Floors and Snowmelting, Springfield, MO (United States). Research and Development Dept.; Eltez, M. [Ege Univ., Izmir (Turkey)

    1996-10-01

    One of the earliest examples of large scale use of the geothermal energy is the district heating system in Boise, Idaho. Established in 1892, this system now serves 266 customers--mostly residential. Today, excluding heat pumps, there are about 300 sites in America where geothermal energy is currently used in various applications; including district heating, absorption cooling and refrigeration, industrial processes, aquaculture, horticulture, and snow melting/freeze protection. Among these, 18 geothermal district heating systems are operating with 677 GBtu (714 TJ) total annual heat output. Geothermal activity was first generated in Italy, in 1904, with a 10 kWe capacity. Now, commercial power plants are in service using vapor-dominated and liquid-dominated plants with a world-wide installed capacity of 6 GWe. This paper looks at a hybrid cycle/integrated district HVAC system.

  11. The Moana geothermal system in Reno, Nevada: A hydrologic, geochemical, and thermal analysis

    SciTech Connect

    Jacobson, E.A.; Johnston, J.W.

    1991-03-01

    The Moana geothermal systems, located in Reno, Nevada, is a moderate-temperature geothermal resource used for space heating applications. Both historic and new hydrologic, thermal, and groundwater chemistry data were collected to evaluate the Moana system and to develop a calibrated numerical model of the geothermal aquifer for investigation of resource development scenarios. The new data collection consisted of static water level measurements and temperature with depth measurements for a 13-month period at 26 geothermal wells to investigate hydrologic and thermal changes with time. In addition, groundwater chemistry sampling at 10 wells was used to evaluate mixing of thermal and nonthermal waters. Collected information indicates that in the most heavily used portion of the geothermal aquifer, the hydraulic heads have declined. This decline may induce additional leakage of cooler water from the overlying unconfined aquifer and lead to decreased temperatures at well locations in the geothermal aquifer. The groundwater chemistry data show concentration changes with temperature for boron, chloride, fluoride, lithium, and bicarbonate that are a function of the degree of mixing of thermal and nonthermal waters. Temporal changes in these constituents may be used as an indication of relative temperature changes in the geothermal system caused by mixing at a given location. An attempt was made to use the hydraulic head and maximum temperature data to develop a calibrated numerical model for the Moana geothermal system. However, lack of information about the horizontal and vertical thermal and fluid fluxes made the development of a calibrated model not possible at this time. 25 refs., 54 figs., 6 tabs.

  12. Evaluation of Oil-Industry Stimulation Practices for Engineered Geothermal Systems

    Microsoft Academic Search

    Peter Van Dyke; Leen Weijers; Ann Robertson-Tait; Norm Warpinski; Mike Mayerhofer; Bill Minner; Craig Cipolla

    2007-01-01

    Geothermal energy extraction is typically achieved by use of long open-hole intervals in an attempt to connect the well with;\\u000athe greatest possible rock mass. This presents a problem for the development of Enhanced (Engineered) Geothermal;\\u000aSystems (EGS), owing to the challenge of obtaining uniform stimulation throughout the open-hole interval. Fluids are often;\\u000ainjected in only a fraction of that

  13. Advanced Horizontal Well Recirculation Systems for Geothermal Energy Recovery in Sedimentary and Crystalline Formations

    SciTech Connect

    Bruno, Mike; Detwiler, Russell L; Lao, Kang; Serajian, Vahid; Elkhoury, Jean; Diessl, Julia; White, Nicky

    2012-12-13

    There is increased recognition that geothermal energy resources are more widespread than previously thought, with potential for providing a significant amount of sustainable clean energy worldwide. Recent advances in drilling, completion, and production technology from the oil and gas industry can now be applied to unlock vast new geothermal resources, with some estimates for potential electricity generation from geothermal energy now on the order of 2 million megawatts. The primary objectives of this DOE research effort are to develop and document optimum design configurations and operating practices to produce geothermal power from hot permeable sedimentary and crystalline formations using advanced horizontal well recirculation systems. During Phase I of this research project Terralog Technologies USA and The University of California, Irvine (UCI), have completed preliminary investigations and documentation of advanced design concepts for paired horizontal well recirculation systems, optimally configured for geothermal energy recovery in permeable sedimentary and crystalline formations of varying structure and material properties. We have also identified significant geologic resources appropriate for application of such technology. The main challenge for such recirculation systems is to optimize both the design configuration and the operating practices for cost-effective geothermal energy recovery. These will be strongly influenced by sedimentary formation properties, including thickness and dip, temperature, thermal conductivity, heat capacity, permeability, and porosity; and by working fluid properties.

  14. Development of a Deep-Penetrating, Compact Geothermal Heat Flow System for Robotic Lunar Geophysical Missions

    NASA Technical Reports Server (NTRS)

    Nagihara, Seiichi; Zacny, Kris; Hedlund, Magnus; Taylor, Patrick T.

    2012-01-01

    Geothermal heat flow measurements are a high priority for the future lunar geophysical network missions recommended by the latest Decadal Survey of the National Academy. Geothermal heat flow is obtained as a product of two separate measurements of geothermal gradient and thermal conductivity of the regolith/soil interval penetrated by the instrument. The Apollo 15 and 17 astronauts deployed their heat flow probes down to 1.4-m and 2.3-m depths, respectively, using a rotary-percussive drill. However, recent studies show that the heat flow instrument for a lunar mission should be capable of excavating a 3-m deep hole to avoid the effect of potential long-term changes of the surface thermal environment. For a future robotic geophysical mission, a system that utilizes a rotary/percussive drill would far exceed the limited payload and power capacities of the lander/rover. Therefore, we are currently developing a more compact heat flow system that is capable of 3-m penetration. Because the grains of lunar regolith are cohesive and densely packed, the previously proposed lightweight, internal hammering systems (the so-called moles ) are not likely to achieve the desired deep penetration. The excavation system for our new heat flow instrumentation utilizes a stem which winds out of a pneumatically driven reel and pushes its conical tip into the regolith. Simultaneously, gas jets, emitted from the cone tip, loosen and blow away the soil. Lab tests have demonstrated that this proboscis system has much greater excavation capability than a mole-based heat flow system, while it weighs about the same. Thermal sensors are attached along the stem and at the tip of the penetrating cone. Thermal conductivity is measured at the cone tip with a short (1- to 1.5-cm long) needle sensor containing a resistance temperature detector (RTD) and a heater wire. When it is inserted into the soil, the heater is activated. Thermal conductivity of the soil is obtained from the rate of temperature increase during the heating. By stopping during the excavation, it is possible to measure thermal conductivities at different depths. The gas jets are turned off when the penetrating cone reaches the target depth. Then, the stem pushes the needle sensor into the undisturbed soil at the bottom of the hole and carries out a thermal conductivity measurement. When the measurement is complete, the system resumes excavation. RTDs, placed along the stem at short (approx 30 cm) intervals, will monitor long-term temperature stability of the subsurface. Temperature in the shallow subsurface would fluctuate with the diurnal, annual, and precession cycles of the Moon. These thermal waves penetrate to different depths into the regolith. Longterm monitoring of the subsurface temperature would allow us to accurately delineate these cyclic signals and separate them from the signal associated with the outward flow of the Moon s endogenic heat. Further, temperature toward bottom of the 3-m hole should be fairly stable after the heat generated during the excavation dissipates into the surrounding soil. The geothermal gradient may be determined reliably from temperature measurements at the RTDs near the bottom. In order to minimize the heat conduction along the stem from affecting the geothermal gradient measurements, we plan to use low-conductive materials for the stem and develop a mechanism to achieve close coupling between the RTDs and the wall of the excavated hole.

  15. Real-time fracture monitoring in Engineered Geothermal Systems with seismic waves

    SciTech Connect

    Jose A. Rial; Jonathan Lees

    2009-03-31

    As proposed, the main effort in this project is the development of software capable of performing real-time monitoring of micro-seismic activity recorded by an array of sensors deployed around an EGS. The main milestones are defined by the development of software to perform the following tasks: • Real-time micro-earthquake detection and location • Real-time detection of shear-wave splitting • Delayed-time inversion of shear-wave splitting These algorithms, which are discussed in detail in this report, make possible the automatic and real-time monitoring of subsurface fracture systems in geothermal fields from data collected by an array of seismic sensors. Shear wave splitting (SWS) is parameterized in terms of the polarization of the fast shear wave and the time delay between the fast and slow shear waves, which are automatically measured and stored. The measured parameters are then combined with previously measured SWS parameters at the same station and used to invert for the orientation (strike and dip) and intensity of cracks under that station. In addition, this grant allowed the collection of seismic data from several geothermal regions in the US (Coso) and Iceland (Hengill) to use in the development and testing of the software.

  16. Recovery Act: Geothermal Data Aggregation: Submission of Information into the National Geothermal Data System, Final Report DOE Project DE-EE0002852 June 24, 2014

    SciTech Connect

    Blackwell, David D. [SMU Geothermal Laboratory; Chickering Pace, Cathy [SMU Geothermal Laboratory; Richards, Maria C. [SMU Geothermal Laboratory

    2014-06-24

    The National Geothermal Data System (NGDS) is a Department of Energy funded effort to create a single cataloged source for a variety of geothermal information through a distributed network of databases made available via web services. The NGDS will help identify regions suitable for potential development and further scientific data collection and analysis of geothermal resources as a source for clean, renewable energy. A key NGDS repository or ‘node’ is located at Southern Methodist University developed by a consortium made up of: • SMU Geothermal Laboratory • Siemens Corporate Technology, a division of Siemens Corporation • Bureau of Economic Geology at the University of Texas at Austin • Cornell Energy Institute, Cornell University • Geothermal Resources Council • MLKay Technologies • Texas Tech University • University of North Dakota. The focus of resources and research encompass the United States with particular emphasis on the Gulf Coast (on and off shore), the Great Plains, and the Eastern U.S. The data collection includes the thermal, geological and geophysical characteristics of these area resources. Types of data include, but are not limited to, temperature, heat flow, thermal conductivity, radiogenic heat production, porosity, permeability, geological structure, core geophysical logs, well tests, estimated reservoir volume, in situ stress, oil and gas well fluid chemistry, oil and gas well information, and conventional and enhanced geothermal system related resources. Libraries of publications and reports are combined into a unified, accessible, catalog with links for downloading non-copyrighted items. Field notes, individual temperature logs, site maps and related resources are included to increase data collection knowledge. Additional research based on legacy data to improve quality increases our understanding of the local and regional geology and geothermal characteristics. The software to enable the integration, analysis, and dissemination of this team’s NGDS contributions was developed by Siemens Corporate Technology. The SMU Node interactive application is accessible at http://geothermal.smu.edu. Additionally, files may be downloaded from either http://geothermal.smu.edu:9000/geoserver/web/ or through http://geothermal.smu.edu/static/DownloadFilesButtonPage.htm. The Geothermal Resources Council Library is available at https://www.geothermal-library.org/.

  17. Creation of an Enhanced Geothermal System through Hydraulic and Thermal Stimulation

    SciTech Connect

    Rose, Peter Eugene [Energy and Geoscience Institute at the University of Utah

    2013-04-15

    This report describes a 10-year DOE-funded project to design, characterize and create an Engineered Geothermal System (EGS) through a combination of hydraulic, thermal and chemical stimulation techniques. Volume 1 describes a four-year Phase 1 campaign, which focused on the east compartment of the Coso geothermal field. It includes a description of the geomechanical, geophysical, hydraulic, and geochemical studies that were conducted to characterize the reservoir in anticipation of the hydraulic stimulation experiment. Phase 1 ended prematurely when the drill bit intersected a very permeable fault zone during the redrilling of target stimulation well 34-9RD2. A hydraulic stimulation was inadvertently achieved, however, since the flow of drill mud from the well into the formation created an earthquake swarm near the wellbore that was recorded, located, analyzed and interpreted by project seismologists. Upon completion of Phase 1, the project shifted focus to a new target well, which was located within the southwest compartment of the Coso geothermal field. Volume 2 describes the Phase 2 studies on the geomechanical, geophysical, hydraulic, and geochemical aspects of the reservoir in and around target-stimulation well 46A-19RD, which is the deepest and hottest well ever drilled at Coso. Its total measured depth exceeding 12,000 ft. It spite of its great depth, this well is largely impermeable below a depth of about 9,000 ft, thus providing an excellent target for stimulation. In order to prepare 46A-19RD for stimulation, however, it was necessary to pull the slotted liner. This proved to be unachievable under the budget allocated by the Coso Operating Company partners, and this aspect of the project was abandoned, ending the program at Coso. The program then shifted to the EGS project at Desert Peak, which had a goal similar to the one at Coso of creating an EGS on the periphery of an existing geothermal reservoir. Volume 3 describes the activities that the Coso team contributed to the Desert Peak project, focusing largely on a geomechanical investigation of the Desert Peak reservoir, tracer testing between injectors 21-2 and 22-22 and the field�������¢����������������s main producers, and the chemical stimulation of target well 27-15.

  18. Creation of an Enhanced Geothermal System through Hydraulic and Thermal Stimulation

    SciTech Connect

    Rose, Peter Eugene [Energy and Geoscience Institute at the Univerity of Utah

    2013-04-15

    This report describes a 10-year DOE-funded project to design, characterize and create an Engineered Geothermal System (EGS) through a combination of hydraulic, thermal and chemical stimulation techniques. Volume 1 describes a four-year Phase 1 campaign, which focused on the east compartment of the Coso geothermal field. It includes a description of the geomechanical, geophysical, hydraulic, and geochemical studies that were conducted to characterize the reservoir in anticipation of the hydraulic stimulation experiment. Phase 1 ended prematurely when the drill bit intersected a very permeable fault zone during the redrilling of target stimulation well 34-9RD2. A hydraulic stimulation was inadvertently achieved, however, since the flow of drill mud from the well into the formation created an earthquake swarm near the wellbore that was recorded, located, analyzed and interpreted by project seismologists. Upon completion of Phase 1, the project shifted focus to a new target well, which was located within the southwest compartment of the Coso geothermal field. Volume 2 describes the Phase 2 studies on the geomechanical, geophysical, hydraulic, and geochemical aspects of the reservoir in and around target-stimulation well 46A-19RD, which is the deepest and hottest well ever drilled at Coso. Its total measured depth exceeding 12,000 ft. It spite of its great depth, this well is largely impermeable below a depth of about 9,000 ft, thus providing an excellent target for stimulation. In order to prepare 46A-19RD for stimulation, however, it was necessary to pull the slotted liner. This proved to be unachievable under the budget allocated by the Coso Operating Company partners, and this aspect of the project was abandoned, ending the program at Coso. The program then shifted to the EGS project at Desert Peak, which had a goal similar to the one at Coso of creating an EGS on the periphery of an existing geothermal reservoir. Volume 3 describes the activities that the Coso team contributed to the Desert Peak project, focusing largely on a geomechanical investigation of the Desert Peak reservoir, tracer testing between injectors 21-2 and 22-22 and the field�s main producers, and the chemical stimulation of target well 27-15.

  19. IN SITU STRESS, FRACTURE, AND FLUID FLOW ANALYSIS IN WELL 38C-9: AN ENHANCED GEOTHERMAL SYSTEM IN THE COSO GEOTHERMAL FIELD

    Microsoft Academic Search

    Judith M. Sheridan; Stephen H. Hickman

    Geoscientists from the Coso Operating Company, EGI-Utah, GeoMechanics International, and the U.S. Geological Survey are cooperating in a multi-year study to develop an Enhanced Geothermal System (EGS) in the Coso Geothermal Field. Key to the creation of an EGS is an understanding of the relationship among natural fracture distribution, fluid flow, and the ambient tectonic stresses that exist within the

  20. Impact of enhanced geothermal systems on US energy supply in the twenty-first century.

    PubMed

    Tester, Jefferson W; Anderson, Brian J; Batchelor, Anthony S; Blackwell, David D; DiPippo, Ronald; Drake, Elisabeth M; Garnish, John; Livesay, Bill; Moore, Michal C; Nichols, Kenneth; Petty, Susan; Toksoz, M Nafi; Veatch, Ralph W; Baria, Roy; Augustine, Chad; Murphy, Enda; Negraru, Petru; Richards, Maria

    2007-04-15

    Recent national focus on the value of increasing US supplies of indigenous renewable energy underscores the need for re-evaluating all alternatives, particularly those that are large and well distributed nationally. A panel was assembled in September 2005 to evaluate the technical and economic feasibility of geothermal becoming a major supplier of primary energy for US base-load generation capacity by 2050. Primary energy produced from both conventional hydrothermal and enhanced (or engineered) geothermal systems (EGS) was considered on a national scale. This paper summarizes the work of the panel which appears in complete form in a 2006 MIT report, 'The future of geothermal energy' parts 1 and 2. In the analysis, a comprehensive national assessment of US geothermal resources, evaluation of drilling and reservoir technologies and economic modelling was carried out. The methodologies employed to estimate geologic heat flow for a range of geothermal resources were utilized to provide detailed quantitative projections of the EGS resource base for the USA. Thirty years of field testing worldwide was evaluated to identify the remaining technology needs with respect to drilling and completing wells, stimulating EGS reservoirs and converting geothermal heat to electricity in surface power and energy recovery systems. Economic modelling was used to develop long-term projections of EGS in the USA for supplying electricity and thermal energy. Sensitivities to capital costs for drilling, stimulation and power plant construction, and financial factors, learning curve estimates, and uncertainties and risks were considered. PMID:17272236

  1. Modeling the effects of silica deposition and fault rupture on natural geothermal systems

    NASA Astrophysics Data System (ADS)

    Dempsey, D. E.; Rowland, J. V.; Zyvoloski, G. A.; Archer, R. A.

    2012-05-01

    Natural geothermal convection abounds within the Taupo Volcanic Zone (TVZ) of New Zealand's Central North Island. In many locations the highly porous eruptive products that blanket the landscape have been altered by the throughput of hydrothermal fluids and the consequent deposition of silica. We detail a numerical model that considers the evolution of a geothermal plume in the presence of silica deposition/dissolution that controls an evolving permeability distribution. Precipitation of silica occurs according to a gradient reaction regime, in which the dissolved silica concentration is controlled by the temperature dependent silica solubility. Over a period of 120 kyr, continuous geothermal circulation leads to the development of a low permeability cap-zone, approximately 200 m thick, above the main geothermal upflow zone. The cap-zone encourages lateral flow of rising fluids, increasing the area across which geothermal expression is observed. It also has an insulating effect on fluids below the cap, causing increases in temperature, enthalpy, and the reservoir potential of the field. A second model is constructed to consider the specific scenario of fault rupture through the impermeable cap-zone. Coseismic increases in permeability along the fault plane produce vigorous, renewed flow through the center of the geothermal field, temporarily reducing lateral flows. However, resealing of near surface permeability is rapid, and the restoration of lateral flows and recovery of the geothermal reservoir occurs within ˜10 kyr. These effects are discussed in the context of two TVZ geothermal fields: the extinct Ohakuri field, and Te Kopia, which is situated on a major active normal fault.

  2. Assessment of the Geothermal System Near Stanley, Idaho

    SciTech Connect

    Trent Armstrong; John Welhan; Mike McCurry

    2012-06-01

    The City of Stanley, Idaho (population 63) is situated in the Salmon River valley of the central Idaho highlands. Due to its location and elevation (6270 feet amsl) it is one of the coldest locales in the continental U.S., on average experiencing frost 290 days of the year as well as 60 days of below zero (oF) temperatures. Because of high snowfall (76 inches on average) and the fact that it is at the terminus of its rural grid, the city also frequently endures extended power outages during the winter. To evaluate its options for reducing heating costs and possible local power generation, the city obtained a rural development grant from the USDA and commissioned a feasibility study through author Roy Mink to determine whether a comprehensive site characterization and/or test drilling program was warranted. Geoscience students and faculty at Idaho State University (ISU), together with scientists from the Idaho Geological Survey (IGS) and Idaho National Laboratory (INL) conducted three field data collection campaigns between June, 2011 and November, 2012 with the assistance of author Beckwith who arranged for food, lodging and local property access throughout the field campaigns. Some of the information collected by ISU and the IGS were compiled by author Mink and Boise State University in a series of progress reports (Makovsky et al., 2011a, b, c, d). This communication summarizes all of the data collected by ISU including data that were compiled as part of the IGS’s effort for the National Geothermal Data System’s (NGDS) data compilation project funded by the Department of Energy and coordinated by the Arizona Geological Survey.

  3. The Role of Boron-Chloride and Noble Gas Isotope Ratios in TVZ Geothermal Systems

    SciTech Connect

    Hulston, J.R.

    1995-01-01

    The model of the geothermal system in which deep circulating groundwater containing noble gases, at air saturated water concentrations, mixes with hot fluids of mantle origin at depth, is extended to include the effect of interaction of the ascending fluid with both solid and gaseous phases of basement (or other) rocks en route to the surface. It is demonstrated that this interaction is responsible for most of the CO{sub 2} in the Taupo Volcanic Zone (TVZ) geothermal systems. It is proposed that the modeling of this interaction might be accomplished by techniques similar to those used for the understanding of the oxygen isotope shift found in geothermal systems. The water rock interaction experiments of Ellis and Mahon (1964, 1967) provides some data on the kinetic rates for B and Cl dissolution from rocks likely to be encountered in the geothermal system, but further information on the behavior of B may be needed. If these problems can be overcome this modeling technique has promise for the estimation of the recharge of geothermal systems and hence the sustainability of these systems.

  4. Strategies for Detecting Hidden Geothermal Systems by Near-Surface Gas Monitoring

    SciTech Connect

    Lewicki, Jennifer L.; Oldenburg, Curtis M.

    2004-12-15

    ''Hidden'' geothermal systems are those systems above which hydrothermal surface features (e.g., hot springs, fumaroles, elevated ground temperatures, hydrothermal alteration) are lacking. Emissions of moderate to low solubility gases (e.g., CO2, CH4, He) may be one of the primary near-surface signals from these systems. Detection of anomalous gas emissions related to hidden geothermal systems may therefore be an important tool to discover new geothermal resources. This study investigates the potential for CO2 detection and monitoring in the subsurface and above ground in the near-surface environment to serve as a tool to discover hidden geothermal systems. We focus the investigation on CO2 due to (1) its abundance in geothermal systems, (2) its moderate solubility in water, and (3) the wide range of technologies available to monitor CO2 in the near-surface environment. However, monitoring in the near-surface environment for CO2 derived from hidden geothermal reservoirs is complicated by the large variation in CO2 fluxes and concentrations arising from natural biological and hydrologic processes. In the near-surface environment, the flow and transport of CO2 at high concentrations will be controlled by its high density, low viscosity, and high solubility in water relative to air. Numerical simulations of CO2 migration show that CO2 concentrations can reach very high levels in the shallow subsurface even for relatively low geothermal source CO2 fluxes. However, once CO2 seeps out of the ground into the atmospheric surface layer, surface winds are effective at dispersing CO2 seepage. In natural ecological systems in the absence of geothermal gas emissions, near-surface CO2 fluxes and concentrations are primarily controlled by CO2 uptake by photosynthesis, production by root respiration, and microbial decomposition of soil/subsoil organic matter, groundwater degassing, and exchange with the atmosphere. Available technologies for monitoring CO2 in the near-surface environment include (1) the infrared gas analyzer (IRGA) for measurement of concentrations at point locations, (2) the accumulation chamber (AC) method for measuring soil CO2 fluxes at point locations, (3) the eddy covariance (EC) method for measuring net CO2 flux over a given area, (4) hyperspectral imaging of vegetative stress resulting from elevated CO2 concentrations, and (5) light detection and ranging (LIDAR) that can measure CO2 concentrations over an integrated path. Technologies currently in developmental stages that have the potential to be used for CO2 monitoring include tunable lasers for long distance integrated concentration measurements and micro-electronic mechanical systems (MEMS) that can make widespread point measurements. To address the challenge of detecting potentially small-magnitude geothermal CO2 emissions within the natural background variability of CO2, we propose an approach that integrates available detection and monitoring methodologies with statistical analysis and modeling strategies. Within the area targeted for geothermal exploration, point measurements of soil CO2 fluxes and concentrations using the AC method and a portable IRGA, respectively, and measurements of net surface flux using EC should be made. Also, the natural spatial and temporal variability of surface CO2 fluxes and subsurface CO2 concentrations should be quantified within a background area with similar geologic, climatic, and ecosystem characteristics to the area targeted for geothermal exploration. Statistical analyses of data collected from both areas should be used to guide sampling strategy, discern spatial patterns that may be indicative of geothermal CO2 emissions, and assess the presence (or absence) of geothermal CO2 within the natural background variability with a desired confidence level. Once measured CO2 concentrations and fluxes have been determined to be of anomalous geothermal origin with high confidence, more expensive vertical subsurface gas sampling and chemical and isotopic analyses can be undertaken. Integrated analysis of all measurements will d

  5. Comparison of Selective Culturing and Biochemical Techniques for Measuring Biological Activity in Geothermal Process Fluids

    SciTech Connect

    Pryfogle, Peter Albert

    2000-09-01

    For the past three years, scientists at the Idaho National Engineering and Environmental Laboratory have been conducting studies aimed at determining the presence and influence of bacteria found in geothermal plant cooling water systems. In particular, the efforts have been directed at understanding the conditions that lead to the growth and accumulation of biomass within these systems, reducing the operational and thermal efficiency. Initially, the methods selected were based upon the current practices used by the industry and included the collection of water quality parameters, the measurement of soluble carbon, and the use of selective medial for the determination of the number density of various types of organisms. This data has been collected on a seasonal basis at six different facilities located at the Geysers’ in Northern California. While this data is valuable in establishing biological growth trends in the facilities and providing an initial determination of upset or off-normal conditions, more detailed information about the biological activity is needed to determine what is triggering or sustaining the growth in these facilities in order to develop improved monitoring and treatment techniques. In recent years, new biochemical approaches, based upon the analyses of phospholipid fatty acids and DNA recovered from environmental samples, have been developed and commercialized. These techniques, in addition to allowing the determination of the quantity of biomass, also provide information on the community composition and the nutritional status of the organisms. During the past year, samples collected from the condenser effluents of four of the plants from The Geysers’ were analyzed using these methods and compared with the results obtained from selective culturing techniques. The purpose of this effort was to evaluate the cost-benefit of implementing these techniques for tracking microbial activity in the plant study, in place of the selective culturing analyses that are currently the industry standard.

  6. Generic Guide Specification for Geothermal Heat Pump Systems

    SciTech Connect

    Thomas, WKT

    2000-04-12

    The attached Geothermal (Ground-Source) Heat Pump (GHP) Guide Specifications have been developed by Oak Ridge National Laboratory (ORNL) with the intent to assist federal agency sites and engineers in the preparation of construction specifications for GHP projects. These specifications have been developed in the industry-standard Construction Specification Institute (CSI) format and cover several of the most popular members of the family of GHP systems. These guide specifications are applicable to projects whether the financing is with conventional appropriations, arranged by GHP specialty ESCOs under the U.S. Department of Energy's Technology-Specific GHP Super ESPCs, arranged by utilities under Utility Energy Service Contracts (UESCs) or arranged by generalist ESCOs under the various regional ESPCs. These specifications can provide several benefits to the end user that will help ensure successful GHP system installations. GHP guide specifications will help to streamline the specification development, review, and approval process because the architecture and engineering (AE) firm will be working from the familiar CSI format instead of developing the specifications from other sources. The guide specifications help to provide uniformity, standardization, and consistency in both the construction specifications and system installations across multiple federal sites. This standardization can provide future benefits to the federal sites in respect to both maintenance and operations. GHP guide specifications can help to ensure that the agency is getting its money's worth from the GHP system by preventing the use of marginal or inferior components and equipment. The agency and its AE do not have to start from scratch when developing specifications and can use the specification as a template and/or a checklist in developing both the design and the contract documents. The guide specifications can save project costs by reducing the engineering effort required during the design development phase. Use of this guide specification for any project is strictly optional and at the discretion of the responsible party in charge. If used as a construction specification master template for GHP systems, this guide specification must, in all cases, be edited to apply to the specific project in question and to reflect the site-specific conditions relevant to the project. There is no guarantee of accuracy or applicability with respect to any portion of this specification and the user assumes all risk associated with the application of the information contained in this document.

  7. Interaction of processes may explain induced seismicity after shut-in in Enhanced Geothermal Systems

    NASA Astrophysics Data System (ADS)

    De Simone, Silvia; Carrera, Jesus; Vilarrasa, Victor

    2015-04-01

    Deep fluid injection is a necessary operation in several engineering sectors, like geothermal energy production, natural gas storage, CO2 storage, etc. The seismicity associated to these activities has, in some occasions, reached unexpected magnitude, raising public concern. Moreover, the occurrence of such seismicity after the injection shut-in pointed out the incompleteness of the knowledge and the inability of fully managing these processes. On the other hand, the growing attention toward clean energy makes it clear that we cannot abandon these procedures, which have a huge potential. Therefore, deeply understanding the mechanisms that induce seismicity is crucial. In this study we consider hydraulic stimulation of deep geothermal systems and analyze the mechanisms that may induce or trigger seismicity. Given that the basic mechanism is fluid pressure increase, secondary triggering processes have been studied. In detail, we attempt to identify the potential mechanisms that may trigger seismicity in the post-injection phase, when the overpressure decreases. These mechanisms have been investigated with a coupled and uncoupled approach, in order to understand the individual effects of each one and the effects of the interactions between them on the reservoir stability. Besides fluid overpressure, another relevant process is the temperature variation. Indeed, in the case of enhanced geothermal systems, the temperature contrast between the injected cold fluid and the deep hot reservoir is great and induces thermal stress, which sensibly affects the in-situ stress field. Therefore, we have studied overpressure and temperature effects by means of analytic solutions and by means of hydro-mechanical and thermo-hydro-mechanical numerical simulations. Results show that in fractured rocks the spatial variability of hydraulic and mechanic parameters provokes no isotropic variation of the tensional field, in response to pressure and temperature perturbations. Another potential mechanism is due to the slip stress transfer. Once failure conditions are reached along a fault or fracture, shear slip is activated and seismic waves propagate. It is well-known that this slip movement affects the stress field in the neighborhood of the slipped fault or fracture. We analyzed the rotation of the stress tensor due to the slip stress transfer and applied it to the thermo-hydro-mechanic simulation results. Results show that the interaction of these different processes may explain post-injection seismicity on not favorably oriented faults.

  8. A geochemical model of the Platanares geothermal system, Honduras

    USGS Publications Warehouse

    Janik, C.J.; Truesdell, A.H.; Goff, F.; Shevenell, L.; Stallard, M.L.; Trujillo, P.E., Jr.; Counce, D.

    1991-01-01

    Results of exploration drilling combined with results of geologic, geophysical, and hydrogeochemical investigations have been used to construct a geochemical model of the Platanares geothermal system, Honduras. Three coreholes were drilled, two of which produced fluids from fractured Miocene andesite and altered Cretaceous to Eocene conglomerate at 450 to 680 m depth. Large volume artesian flows of 160-165??C, predominantly bicarbonate water are chemically similar to, but slightly less saline than widespread boiling hot-spring waters. The chemistry of the produced fluid is dominated by equilibrium reactions in sedimentary rocks at greater depths and higher temperatures than those measured in the wells. Chemical, isotope, and gas geothermometers indicate a deep fluid temperature of 200-245??C and reflect a relatively short residence time in the fractures feeding the wells. Chloride-enthalpy relations as well as isotopic and chemical compositions of well discharges, thermal springs, and local cold waters support a conceptual model of ascending high-temperature (minimum 225??C) parent fluid that has cooled conductively to form the 160-165??C shallow (to 680 m) fluid encountered by the wells. The hot-spring waters are formed by boiling and steam loss from more or less conductively cooled parent fluid. The more dilute boiling spring waters (Cl = ???32 mg/kg) have cooled from > 225??C to about 160??C by conduction and from 160??C to 98??C by boiling. The most concentrated boiling spring waters (Cl = 37 mg/kg) have cooled from > 225??C to about 200??C by conduction and from 200??C to 98??C by boiling. Intermediate concentrations reflect mixed cooling paths. ?? 1991.

  9. The Design of Large Geothermally Powered Air-Conditioning Systems Using an Optimal Control Approach

    Microsoft Academic Search

    F. G. Horowitz; L. O'Bryan

    2010-01-01

    The direct use of geothermal energy from Hot Sedimentary Aquifer (HSA) systems for large scale air-conditioning projects involves many tradeoffs. Aspects contributing towards making design decisions for such systems include: the inadequately known permeability and thermal distributions underground; the combinatorial complexity of selecting pumping and chiller systems to match the underground conditions to the air-conditioning requirements; the future price variations

  10. Development of a Distributed Control System (DCS) for Geothermal Steamfield Operations at Kawerau, NZ

    SciTech Connect

    Koorey, K.J.

    1995-01-01

    A distributed control system (DCS) has been developed for operation of the Kawerau geothermal field. The DCS functions include steam pressure control, steam flow billing, flow and pressure monitoring, remote well flow control and auto paging field operators. The system has evolved over a number of years from paper chart recorders to dataloggers to a desktop PC system to an industrial DCS.

  11. (Sulfide-oxide-silicate phase equilibria and associated fluid inclusion properties in the Salton Sea geothermal system, California)

    SciTech Connect

    McKibben, M.A.

    1988-06-01

    Our studies involved petrographic, fluid inclusion, geochemical and stable isotopic studies of drillcores and fluids from the Salton Sea geothermal system. Our initial studies revealed the presence of previously-unrecognized evaporitic anhydrite at depth throughout the geothermal system. The high salinity of the Salton Sea geothermal brines previously had been attributed to low-temperature dissolution of surficial evaporitic deposits by meteoric waters. Our microthermometric studies of halite--containing fluid inclusions in the meta-evaporites indicated that the high salinity of the geothermal brines is derived in part from the hydrothermal metamorphism of relatively deeply-buried salt and evaporites. In addition, our research concentrated on mineralized fractures in drillcores.

  12. Direct utilization of geothermal heat in cascade application to aquaculture and greenhouse systems at Navarro College. Annual report, January 1984-September 1984

    SciTech Connect

    Smith, K.

    1984-09-01

    Progress is reported on a project to use the 130/sup 0/F geothermal resource in central Texas. The system for cascading geothermal energy through aquaculture and greenhouse systems was completed and the first shrimp harvest was held. (MHR)

  13. Upscaling of Thermal Transport Properties in Enhanced Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Johnson, S.; Hao, Y.; Chiaramonte, L.

    2010-12-01

    : Engineered Geothermal Systems (EGS) have garnered significant attention as a possible source of geographically disperse, carbon-free energy without the environmental impact of many other renewable energy sources. However, a significant barrier to the adoption of EGS is the uncertainty in whether a specific site is amenable to engineering and how fluid injection rates can affect, either through stimulation of the fracture network or through deleterious channeling of the thermal fluid, the heat extraction rate possible in a specific reservoir. Because of the uncertainties involved in determining the exact fracture network topology extant in any particular reservoir, it is desirable to have a stochastic description (distribution) of the possible heat extraction rates that could be achieved. This work provides both an approach and application of the approach for simulating several synthetic fracture networks. The approach uses a coupled geomechanics and discrete fracture network (DFN) solver coupled uni-directionally with a reservoir scale, hydro-thermal transport code, the Non-isothermal Unsaturated-Saturated Flow and Transport simulation code (NUFT), to capture the coupled hydro-thermo-mechanical behavior of these synthetic networks. Particular attention is paid to the upscaling approach used to determine effective permeability and thermal transfer coefficients that are used in the dual porosity/permeability (DKM) model employed in NUFT. This upscaling is based on a multi-scale treatment of the domain, starting with the upscaling of permeability from explicitly represented fractures in the DFN model, which considers the fracture-scale effects of fluid injection, to a finely resolved, unstructured mesh representation of the subdomain. Effective properties of this subdomain are then determined for a variety of sub-sampled discrete fracture network topologies. The result catalog of spatially correlated thermal and fluid properties are then used to populate the properties of an anisotropic regular grid representation of the reservoir. The resultant reservoir-scale system considering the fully-coupled hydro-thermo-mechanical problem is then simulated to determine the resultant heat transfer rate for each synthetic fracture network realization. To complete the parametric study, several fractally spatially distributed systems are realized for each fractal dimension value. The resultant distributions of heat transfer rate and the trends emergent from this study will be presented. Auspices: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  14. Modifications for geothermal-heating system for Kingswood Apartments, Klamath Falls, Oregon

    SciTech Connect

    Not Available

    1982-04-01

    The Kingswood Apartments, located on Eberlein Street in Klamath Falls, are currently heated by a geothermal well producing 118/sup 0/F water. Geothermal water from the well is piped directly through fan coil units in each of the 117 apartments and disposed of in the storm sewer system. Since the installation of the system in 1975, a large number of corrosion failures of the finned tube coils have occured with increasing frequency. This corrosion is probably the result of small concentrations of hydrogen sulfide (H/sub 2/S) dissolved in the geothermal water. This constituent is not compatible with the copper of which the finned coils are made. The possibility of modifying the existing, open type piping system to a closed loop/heat exchanger design to minimize the current corrosion problems is explored.

  15. Thermodynamic and kinetic modeling of mineralogical evolution in the Soultz-sous-Forêts geothermal system: insights into the reaction pathways

    NASA Astrophysics Data System (ADS)

    Van Ngo, Viet; Lucas, Yann; Clément, Alain; Fritz, Bertrand

    2015-04-01

    The energy production from hot fractured rocks has been investigated at the Soultz-sous-Forêts EGS (Alsace, France) from nearly three decades. Three wells have been drilled up to the depth of about 5000 m in which two wells are served as the fluid production and the third as a fluid re-injection. The circulation of geothermal fluids through the fractured reservoir leads to a strong chemical nonequilibrium of the solid and aqueous phases, which potentially cause changes in porosity, permeability, and flow pathways of the geothermal reservoir. Numerous experimental and modeling studies (e.g., Dubois et al., 2000; Baldeyrou et al., 2003; Ledésert et al., 2009; Fritz et al., 2010; Ledésert et al., 2010) carried out within the framework of the Soultz-sous-Forêts system have reported that quartz, calcite and illites are formed as the major secondary phases in the main fractures. Some contributions among the above publications further indicated that calcite plays an important role in the reduction of permeability of the fractured zones and illites are considered as a characteristic product of the hydrothermal vein alteration. Therefore, it is important to predict the evolution of minerals (especially for quartz, calcite, and illites), which may potentially modify the transport properties of the geothermal reservoir (e.g., Ledésert et al., 2009; Fritz et al., 2010). Understanding the changes in mineralogy in the fractured zones is also useful to choose the reagents in order to improve the permeability of the geothermal reservoir via the chemical stimulation. The overall objectives of the current study are to (i) investigate the long-term evolution of mineralogy in the geothermal Soultz-sous-Forêts Enhanced Geothermal System (EGS), (ii) establish the relationship between different mineral groups, (iii) study the reaction pathways, and (iv) compare the thermodynamic and kinetic approaches. The numerical calculations carried out using the KINDIS numerical code were realized with the thermodynamic and kinetic approaches that only differ in that the precipitation of the main minerals including quartz, calcite, and illites was treated thermodynamically and kinetically. The two approaches have other identical factors such as: all primary minerals are dissolved kinetically; other secondary minerals are formed at equilibrium. The modeling results showed that reaction pathways predicted by two approaches were slightly different. The difference was clearly indicated by the precipitation amount of quartz, calcite and illites, as well as the formation patterns of these minerals. Moreover, the difference in reaction pathways was also demonstrated by the activity diagrams, which presented th@unistra.fre relationship of various mineral groups. Altogether, the system stability fell in the stability zones of the main minerals such as calcite, illites. These findings highlighted the importance of the minerals like quartz, calcite, and illites. Our work further suggested that the kinetic approach would be more appropriate for the coupled thermo-hydro-chemical model in order to predict the long term evolution of the geothermal reservoir. This method can be applied with a great benefit to other geothermal reservoirs for a better understanding of the mineralogy evolution. References: Balderyou et al., Comptes Rendus Geoscience 335(4), 371-380; Dubois et al., Earth and Planetary Science 331(4), 303-309; Fritz et al., Comptes Rendus Geoscience 342(7-8), 653-667; Ledésert et al., Comptes Rendus Geoscience 342(7-8), 607-615; Ledésert et al., Journal of Volcanology and Geothermal Research 181(1-2), 106-114.

  16. Emerging geothermal energy technologies

    Microsoft Academic Search

    I. W. Johnston; S. Colls

    2011-01-01

    Geothermal energy, whether as a source of electricity or to heat or cool buildings, has an enormous potential as a renewable energy source. This paper presents a broad overview of geothermal energy, with a focus on the emerging technologies of Enhanced Geothermal Systems (EGS) and Ground Source Heat Pumps (GSHPs). EGS and GSHP systems are important because of their potential

  17. Geothermal energy in Nevada

    SciTech Connect

    Not Available

    1980-01-01

    The nature of goethermal resources in Nevada and resource applications are discussed. The social and economic advantages of utilizing geothermal energy are outlined. Federal and State programs established to foster the development of geothermal energy are discussed. The names, addresses, and phone numbers of various organizations actively involved in research, regulation, and the development of geothermal energy are included. (MHR)

  18. ASSESSMENT OF HIGH-TEMPERATURE GEOTHERMAL RESOURCES IN HYDROTHERMAL CONVECTION SYSTEMS IN THE UNITED STATES.

    USGS Publications Warehouse

    Nathenson, Manuel

    1984-01-01

    The amount of thermal energy in high-temperature geothermal systems (>150 degree C) in the United States has been calculated by estimating the temperature, area, and thickness of each identified system. These data, along with a general model for recoverability of geothermal energy and a calculation that takes account of the conversion of thermal energy to electricity, yield a resource estimate of 23,000 MWe for 30 years. The undiscovered component was estimated based on multipliers of the identified resource as either 72,000 or 127,000 MWe for 30 years depending on the model chosen for the distribution of undiscovered energy as a function of temperature.

  19. Numerical modeling of geothermal heat pump system: evaluation of site specific groundwater thermal impact

    NASA Astrophysics Data System (ADS)

    Pedron, Roberto; Sottani, Andrea; Vettorello, Luca

    2014-05-01

    A pilot plant using a geothermal open-loop heat pump system has been realized in the city of Vicenza (Northern Italy), in order to meet the heating and cooling needs of the main monumental building in the historical center, the Palladian Basilica. The low enthalpy geothermal system consists of a pumping well and a reinjection well, both intercepting the same confined aquifer; three other monitoring wells have been drilled and then provided with water level and temperature dataloggers. After about 1 year and a half of activity, during a starting experimental period of three years, we have now the opportunity to analyze long term groundwater temperature data series and to evaluate the numerical modeling reliability about thermal impact prediction. The initial model, based on MODFLOW and SHEMAT finite difference codes, has been calibrated using pumping tests and other field investigations data, obtaining a valid and reliable groundwater flow simulation. But thermal parameters, such as thermal conductivity and volumetric heat capacity, didn't have a site specific direct estimation and therefore they have been assigned to model cells referring to bibliographic standards, usually derived from laboratory tests and barely representing real aquifer properties. Anyway preliminary heat transport results have been compared with observed temperature trends, showing an efficient representation of the thermal plume extension and shape. The ante operam simulation could not consider heat pump real utilization, that happened to be relevantly different from the expected project values; so the first numerical model could not properly simulate the groundwater temperature evolution. Consequently a second model has been implemented, in order to calibrate the mathematical simulation with monitored groundwater temperature datasets, trying to achieve higher levels of reliability in heat transport phenomena interpretation. This second step analysis focuses on aquifer thermal parameters calibration and includes a new finite element FEFLOW simulation, as an useful comparison between different approaches to heat transport modeling.

  20. Hydrochemistry and geothermometrical modeling of low-temperature Panticosa geothermal system (Spain)

    NASA Astrophysics Data System (ADS)

    Asta, Maria P.; Gimeno, Maria J.; Auqué, Luis F.; Gómez, Javier; Acero, Patricia; Lapuente, Pilar

    2012-08-01

    The chemical characteristics of the low-temperature geothermal system of Panticosa (Spain) were investigated in order to determine the water temperature at the reservoir and to identify the main geochemical processes that affect the water composition during the ascent of the thermal waters. In general, the studied waters are similar to other geothermal systems in the Pyrenees, belonging to the group of granite-related alkaline thermal waters (high pH, low total dissolved solids, very low magnesium concentration, and sodium as the dominant cation). According to the alkaline pH of these waters, they have a very low CO2 partial pressure, bicarbonate is the dominant anion and silica is partially ionized as H3SiO4-. The unusually active acid-base pairs (HCO3-/CO32 - and, mainly, H4SiO4/H3SiO4-) act as homogeneous pH buffers and contribute to the total alkalinity in these alkaline waters. On the basis of the study of the conservative elements, a mixing process between a hot and a cold end-member has been identified. Additionally, in order to determinate the water temperature at the reservoir, several geothermometric techniques have been applied, including both geothermometrical modeling and classical geothermometrical calculations. The geothermometrical modeling seems to indicate that thermal waters re-equilibrate with respect to calcite and kaolinite during their ascent to the surface. Modeling results suggest that these thermal waters would be in equilibrium with respect to albite, K-feldspar, quartz, calcite, kaolinite and zoisite at a similar temperature of 90 ± 20 °C in the reservoir, which is in good agreement with the results obtained by applying the classical geothermometers.

  1. Understanding the Chena Hot Springs, Alaska, geothermal system using temperature and pressure data from exploration boreholes

    Microsoft Academic Search

    Kamil Erkan; Gwen Holdmann; Walter Benoit; David Blackwell

    2008-01-01

    Chena Hot Springs is a small, moderate temperature, deep circulating geothermal system, apparently typical of those associated to hot springs of interior Alaska. Multi-stage drilling was used in some exploration boreholes and was found to be useful for understanding subsurface flow characteristics and developing a conceptual model of the system. The results illustrate how temperature profiles illuminate varying pressure versus

  2. Mineral-fluid interaction in the Reykjanes and Svartsengi geothermal systems, Iceland

    Microsoft Academic Search

    S. W. Lonker; H. Franzson; H. Kristmannsdottir

    2009-01-01

    Physical observations on features such as temperature, pressure, and formation permeability are integrated with alteration intensity, fluid and secondary mineral compositions, and textures to show the most important thermal, chemical, hydrodynamic, and kinetics factors that control the evolution of two Icelandic geothermal systems, the Reykjanes and Svartsengi systems. There is an increase in alteration intensity and the abundance of fracture

  3. Computer simulation of borehole ground heat exchangers for geothermal heat pump systems

    Microsoft Academic Search

    C. K. Lee; H. N. Lam

    2008-01-01

    Computer simulation of borehole ground heat exchangers used in geothermal heat pump systems was conducted using three-dimensional implicit finite difference method with rectangular coordinate system. Each borehole was approximated by a square column circumscribed by the borehole radius. Borehole loading profile calculated numerically based on the prescribed borehole temperature profile under quasi-steady state conditions was used to determine the ground

  4. Geothermal direct-heat utilization assistance. Quarterly project progress report, January--March 1996

    SciTech Connect

    NONE

    1996-05-01

    This report summarizes geothermal technical assistance, R&D, and technology transfer activities of the Geo-Heat Center. It describes 95 contacts with parties during this period related to technical assistance with goethermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, equipment, economics, and resources. Research activities are summarized on geothermal district heating system cost evaluation and silica waste utilization project. Outreach activities include publication of a geothermal direct use Bulletin, dissemination of information, goethermal library, technical papers and seminars, and progress monitor reports on geothermal resources and utilization.

  5. Development of Models to Simulate Tracer Behavior in Enhanced Geothermal Systems

    SciTech Connect

    Williams, Mark D.; Vermeul, Vincent R.; Reimus, P. W.; Newell, D.; Watson, Tom B.

    2010-06-01

    A recent report found that power and heat produced from engineered (or enhanced) geothermal systems (EGSs) could have a major impact on the United States while incurring minimal environmental impacts. EGS resources differ from high-grade hydrothermal resources in that they lack sufficient temperature distributions, permeability/porosity, fluid saturation, or recharge of reservoir fluids. Therefore, quantitative characterization of temperature distributions and the surface area available for heat transfer in EGS is necessary for commercial development of geothermal energy. The goal of this project is to provide integrated tracer and tracer interpretation tools to facilitate this characterization. Modeling capabilities are being developed as part of this project to support laboratory and field testing to characterize engineered geothermal systems in single- and multi-well tests using tracers. The objective of this report is to describe the simulation plan and the status of model development for simulating tracer tests for characterizing EGS.

  6. Selected data for low-temperature (less than 90{sup 0}C) geothermal systems in the United States: reference data for US Geological Survey Circular 892

    SciTech Connect

    Reed, M.J.; Mariner, R.H.; Brook, C.A.; Sorey, M.L.

    1983-12-15

    Supporting data are presented for the 1982 low-temperature geothermal resource assessment of the United States. Data are presented for 2072 geothermal sites which are representative of 1168 low-temperature geothermal systems identified in 26 States. The low-temperature geothermal systems consist of 978 isolated hydrothermal-convection systems, 148 delineated-area hydrothermal-convection systems, and 42 delineated-area conduction-dominated systems. The basic data and estimates of reservoir conditions are presented for each geothermal system, and energy estimates are given for the accessible resource base, resource, and beneficial heat for each isolated system.

  7. NATIONAL GEOTHERMAL DATA SYSTEM: AN EXEMPLAR OF OPEN ACCESS TO DATA

    SciTech Connect

    Blackman, Harold [Arizona Geological Survey; Blackman, Harold M. [Arizona Geological Survey; Blackman, Harold M. [Arizona Geological Survey; Blackman, Harold [Boise State University; Blackman, Harold [United States Department of Energy; Blackman, Harold

    2013-10-01

    The formal launch of National Geothermal Data System (NGDS – www.geothermaldata.org) in 2014 will provide open access to technical geothermal-relevant data from all of the Department of Energy- sponsored geothermal development and research projects and geologic data from all 50 states. By making data easily discoverable and accessible this system will open new exploration opportunities and shorten project development. The prototype data system currently includes multiple data nodes, and nationwide data online and available to the public, indexed through a single catalog under construction at http://search.geothermaldata.org. Data from state geological surveys and partners includes more than 5 million records online, including 1.48 million well headers (oil and gas, water, geothermal), 732,000 well logs, and 314,000 borehole temperatures and is growing rapidly. There are over 250 Web services and another 138 WMS (Web Map Services) registered in the system as of August, 2013. Additional data record is being added by companion projects run by Boise State University, Southern Methodist University, and the USGS. The National Renewable Energy Laboratory is managing the Geothermal Data Repository, an NGDS node that will be a clearinghouse for data from hundreds of DOE-funded geothermal projects. NGDS is built on the US Geoscience Information Network (USGIN) data integration framework, which is a joint undertaking of the USGS and the Association of American State Geologists (AASG). NGDS is fully compliant with the White House Executive Order of May 2013, requiring all federal agencies to make their data holdings publicly accessible online in open source, interoperable formats with common core and extensible metadata. The National Geothermal Data System is being designed, built, deployed, and populated primarily with grants from the US Department of Energy, Geothermal Technologies Office. To keep this operational system sustainable after the original implementation will require four core elements: continued serving of data and applications by providers; maintenance of system operations; a governance structure; and an effective business model. Each of these presents a number of challenges currently under consideration.

  8. CO2 DRIVEN HYDROTHERMAL ERUPTIONS IN GEOTHERMAL SYSTEMS OF TURKEY

    Microsoft Academic Search

    I. Tonguç Uysal; Jian-xin Zhao; Yue-xing Feng; Suzanne D. Golding

    2009-01-01

    Substantial CO2 degassing occurs from geothermal waters in Turkey as evident from ongoing deposition of recent terrace travertines and emplacement of significant travertine vein and breccia deposits representing hydrothermal eruption products. Geochemical data indicate rapid ascent of CO2- bearing fluids without significant interaction with basement and host rocks. High-precision U-series dates of most travertine veins coincide with times of cold\\/dry

  9. Development and Exploitation of Low Enthalpy Geothermal Systems, Example of \\

    Microsoft Academic Search

    J. Rojas; A. Menjoz; J. C. Martin; A. Criaud; C. Fouillac

    1987-01-01

    A feature of French geothermal engineering is the development of industrial projects in normal gradient, non-convective areas. The economic feasibility of exploiting wells producing between 150 and 350 m³\\/h at temperatures from 55° to 85° from depths of 1,500 to 2,000 meters, in sedimentary basins with normal gradient, for direct heat production has been proved by 50 plants providing heating

  10. Near-Surface CO2 Monitoring And Analysis To Detect Hidden Geothermal Systems

    SciTech Connect

    Lewicki, Jennifer L.; Oldenburg, Curtis M.

    2005-01-19

    ''Hidden'' geothermal systems are systems devoid of obvious surface hydrothermal manifestations. Emissions of moderate-to-low solubility gases may be one of the primary near-surface signals from these systems. We investigate the potential for CO2 detection and monitoring below and above ground in the near-surface environment as an approach to exploration targeting hidden geothermal systems. We focus on CO2 because it is the dominant noncondensible gas species in most geothermal systems and has moderate solubility in water. We carried out numerical simulations of a CO2 migration scenario to calculate the magnitude of expected fluxes and concentrations. Our results show that CO2 concentrations can reach high levels in the shallow subsurface even for relatively low geothermal source CO2 fluxes. However, once CO2 seeps out of the ground into the atmospheric surface layer, winds are effective at dispersing CO2 seepage. In natural ecological systems in the absence of geothermal gas emissions, near-surface CO2 fluxes and concentrations are predominantly controlled by CO2 uptake by photosynthesis, production by root respiration, microbial decomposition of soil/subsoil organic matter, groundwater degassing, and exchange with the atmosphere. Available technologies for monitoring CO2 in the near-surface environment include the infrared gas analyzer, the accumulation chamber method, the eddy covariance method, hyperspectral imaging, and light detection and ranging. To meet the challenge of detecting potentially small-magnitude geothermal CO2 emissions within the natural background variability of CO2, we propose an approach that integrates available detection and monitoring techniques with statistical analysis and modeling strategies. The proposed monitoring plan initially focuses on rapid, economical, reliable measurements of CO2 subsurface concentrations and surface fluxes and statistical analysis of the collected data. Based on this analysis, are as with a high probability of containing geothermal CO2 anomalies can be further sampled and analyzed using more expensive chemical and isotopic methods. Integrated analysis of all measurements will determine definitively if CO2 derived from a deep geothermal source is present, and if so, the spatial extent of the anomaly. The suitability of further geophysical measurements, installation of deep wells, and geochemical analyses of deep fluids can then be determined based on the results of the near surface CO2 monitoring program.

  11. Reservoir modelling of deep geothermal systems: the examples of Guardia Lombardi

    NASA Astrophysics Data System (ADS)

    Montegrossi, Giordano; Inversi, Barbara; Scrocca, Davide

    2013-04-01

    In the framework of the VIGOR project, a characterization of medium enthalpy geothermal resources was carried out in the Campania region (southern Italy), with a focus on the "Guardia dei Lombardi" area (Avellino). The VIGOR project started on the basis of an agreement between the Ministry of Economic Development and the Italian National Research Council, and it deals with the exploitation of innovative uses of geothermal energy in the so-called "regions of convergence" (Campania, Calabria, Puglia and Sicily). One of the main results of this research is the development of an integrated 3D geological model, which provides the base for a detailed assessment of possible geothermal exploitation of the carbonate reservoir. The preliminary results of our study suggest that "Guardia dei Lombardi" can be indicated as an interesting area for medium enthalpy geothermal exploitation, although the presence of a CO2 gas cap and the scaling capability of the deep fluids need to be carefully evaluated. The aim of this work is to give an estimation of a geothermal well productivity, in the case of a geothermal exploitation. The geothermal well that is thought to be more suitable in the Guardia dei Lombardi Area is named Bonito 1 Dir, a well with a measured temperature of 118 °C at 3,107m depth, which gives a corrected temperature of 138 °C with an error of 8 °C. The pressure was found to be nearly hydrostatic, with 266.9 bar at 2992.4 m depth, and the potential reservoir is hosted in the Mesozoic carbonate formation. According to hydraulic tests, we found that the permeability porosity product gives nearly 100 mD for the carbonatic formation. Since the matrix porosity is nearly 1% with 0.65 mD from core drilled tests, the result of the hydraulic test is to be related to a fractured system; in this case, there is no a clear relation among porosity and permeability, thus we had a sensitivity check on the possible porosity-permeability values of the system, keeping as a constrain the value obtained from the hydraulic test. From the 3D geological model we obtained the boundary of the carbonate formation hosting the geothermal reservoir, and we modelled the cases of both a single producing well and a geothermal doublet in order to give an estimation of the geothermal potential. Deposition of calcite in a formation may significantly reduce the inflow performance of geothermal wells producing brine with CO2-rich content. The key operational and reservoir parameters influencing the magnitude of impairment by calcite deposition were identified through the numerical modelling of the rate of calcite deposition and its effect on flow rate assuming idealized flow conditions. This is an important constrain for a well lifetime, especially in the case of a 138 °C well, because the power production requires a large fluid flow, and an encrustating fluid may severely affect the geothermal well performance. The results of the model, in terms of fluid flow at wellhead and scaling potential, will be available for an economic evaluation of the feasibility of geothermal exploitation of the Bonito 1 Dir well, in the Guardia dei Lombardi area.

  12. A proposal to investigate higher enthalpy geothermal systems in the USA

    NASA Astrophysics Data System (ADS)

    Elders, W. A.

    2013-12-01

    After more than 50 years of development only ~3,400 MWe of electric power is currently being produced from geothermal resources in the USA. That is only about 0.33% of the country's total installed electrical capacity. In spite of the large demonstrated potential of geothermal resources, only ~2,500 MWe of new geothermal electrical capacity are under development, and the growth rate of this environmentally benign energy resource is overshadowed by the rapid increase in the installed capacity of wind and solar energy. Most of the new geothermal developments in the USA involve relatively small, moderate-temperature, geothermal systems. In contrast, development of higher enthalpy geothermal systems for power production has obvious advantages; specifically higher temperatures yield higher power outputs per well so that fewer wells are needed, leading to smaller environmental footprints for a given size of power plant. Disadvantages include that the fact that locations of suitable geothermal systems are restricted to young volcanic terrains, production of very high enthalpy fluids usually requires drilling deeper wells and may require enhanced geothermal (EGS) technology, and drilling deep into hot hostile environments is technologically challenging. However the potential for very favorable economic returns suggests that the USA should begin developing such a program. One approach to mitigating the cost issue is to form a consortium of industry, government and academia to share the costs and broaden the scope an investigation. An excellent example of such a collaboration is the Iceland Deep Drilling Project (IDDP) which is investigating the economic feasibility of producing electricity from supercritical geothermal reservoirs. This industry-government consortium planned to drill a deep well in the volcanic caldera of Krafla in NE Iceland. However drilling had to be terminated at 2.1 km depth when 900°C rhyolite magma flowed into the well. The resultant well was highly productive capable of generating >35 MWe from superheated steam at a well-head temperature of ~450°C. Plans for deep drilling to explore for deeper, much higher enthalpy, geothermal resources are already underway in the Taupo Volcanic Zone of New Zealand (Project HADES), and in northeast Japan the 'Beyond Brittle Project' (Project JBBP) is an ambitious program attempting to create an EGS reservoir in ~500oC rocks. However in the USA there is no comparable national program to develop such resources. There is a significant undeveloped potential for developing high-enthalpy geothermal systems in the western USA, Hawaii and Alaska. The purpose of this paper is to encourage the formation of a consortium to systematically explore, assess, and eventually develop such higher-enthalpy geothermal resources. Not only would this help develop large new sources of energy but it would permit scientific studies of pressure-temperature regimes not otherwise available for direct investigation, such as the coupling of magmatic and hydrothermal systems.

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

    SciTech Connect

    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.

  14. Evaluation of noise associated with geothermal-development activities. Final report, July 31, 1979-April 30, 1982

    SciTech Connect

    Long, M.; Stern, R.

    1982-01-01

    This report was prepared for the purpose of ascertaining the current state of noise generation, suppression, and mitigation techniques associated with geothermal development. A description of the geothermal drilling process is included as well as an overview of geothermal development activities in the United States. Noise sources at the well site, along geothermal pipelines, and at the power plants are considered. All data presented are measured values by workers in the field and by Marshall Long/Acoustics. One particular well site was monitored for a period of 55 continuous days, and includes all sources of noise from the time that the drilling rig was brought in until the time that it was moved off site. A complete log of events associated with the drilling process is correlated with the noise measurements including production testing of the completed well. Data are also presented which compare measured values of geothermal noise with federal, state, county, and local standards. A section on control of geothermal noise is also given. Volume I of this document presents summary information.

  15. Lithosphere tectonics and thermo-mechanical properties: An integrated modelling approach for Enhanced Geothermal Systems exploration in Europe

    Microsoft Academic Search

    S. Cloetingh; J. D. van Wees; P. A. Ziegler; L. Lenkey; F. Beekman; M. Tesauro; A. Förster; B. Norden; M. Kaban; N. Hardebol; D. Bonté; A. Genter; L. Guillou-Frottier; M. Ter Voorde; D. Sokoutis; E. Willingshofer; T. Cornu; G. Worum

    2010-01-01

    Knowledge of temperature at drillable depth is a prerequisite in site selection for geothermal exploration and development of enhanced geothermal systems (EGS). Equally important, the thermo-mechanical signature of the lithosphere and crust provides critical constraints for the crustal stress field and basement temperatures where borehole observations are rare. The stress and temperature field in Europe is subject to strong spatial

  16. Thermal and hydrochemical anomalies due to large-scale thermohaline convection in Seferihisar-Balçova Geothermal system, Western Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Magri, F.; Pekdeger, A.; Gemici; Akar, T.

    2009-12-01

    The Seferihisar-Balçova Geothermal system (SBG), Western Anatolia, Turkey, is characterized by complex temperature and hydrochemical anomalies which causes are not fully understood. Previous geophysical investigations suggested that hydrothermal convection in the faulted areas of the SBG and recharge flow from the Horst may be possible transport mechanisms underlying the observed patterns. A numerical model of thermohaline flow along a North-South transect has been built in order to study the possible fluid-fluid dynamics of deep geothermal groundwater flow in the SBG. The results support the hypothesis derived from interpreted data. The interaction between forced convection from the Seferihisar Highs and free convection in the faults (i.e. mixed convection) is likely the major transport mechanism responsible for the observed anomalies. Furthermore the simulations scenarios allowed to gain a better understanding of the geophysical conditions under which the different fluid-dynamics are likely to develop. At weak recharge conditions, the convective patterns in the faults can extend to surrounding reservoir-units or below seafloor. These fault-induced drag forces can extend from the seafloor to the faults and induce natural seawater intrusion. In the units of the Seferihisar Horst, the regional flow patterns are modified by the buoyant-driven flow focused in the series of vertical faults. As a result, the main groundwater divide in the basin can shift. Sealing caprocks prevent fault-induced cells from being overwhelmed by vigorous regional flow. In this case, over-pressured blind geothermal reservoirs are likely to form below the caprocks. Transient results showed that the front of rising hot waters in faults is unstable: the tip of the hydrothermal plumes can split and lead to periodical temperature oscillations in more permeable unit. This phenomenon known as the Taylor-Saffman fingering has been described in mid-ocean ridge hydrothermal systems. Our findings suggest that this type of thermal pulsing could also develop in active faulted geothermal systems. To some extent the role of an impervious fault-core on the flow patterns has also been investigated. Although it is not possible to reproduce basin-scale transport processes of coupled heat and fluid flow in faulted hydrothermal systems, this first attempt to model deep geothermal groundwater flow in the SBG qualitatively supported the interpreted data and described the different fluid-dynamics of the basin.

  17. CO2B: a computer program for applying a gas geothermometer to geothermal systems

    NASA Astrophysics Data System (ADS)

    Saracco, Lorenza; D'Amore, Franco

    This paper describes the computer program CO2B used to calculate some geothermal reservoir parameters starting from natural-gas composition (CO 2, H 2S, H 2, CH 4, CO in molal percentage in dry gas). A numerical approach has been used to solve sets of nonlinear equations derived from gas chemical equilibria. The following reservoir parameters are computed: temperature, steam fraction, CO 2 partial pressure, gas H 2O ratio, and redox conditions (oxygen and sulphur partial pressures). The model used in this paper may be considered valid only for geothermal systems with reservoir temperature ranging between 140 and 370°C.

  18. A materials and equipment review of selected US geothermal district heating systems

    SciTech Connect

    Rafferty, K.D.

    1989-07-01

    This collection of information was assembled for the benefit of future geothermal system designers and existing system operators. It is intended to provide insight into the experience gained from the operation of 13 major geothermal systems over the past several years. Each chapter contains six or seven sections depending upon the type of system: introduction, production facilities, distribution, customer connections, metering and disposal. Some chapters, covering systems which incorporate a closed distribution design include a section on the central mechanical room. Each section details the original equipment and materials installed in that portion of the system. Following each section is a discussion of the subsequent problems, solutions and modifications relating to the equipment. The extent to which information was available varied from system to system. This is reflected in the length and level of detail of the chapters.

  19. Integrated mineralogical and fluid inclusion study of the Coso geothermal systems, California

    SciTech Connect

    Lutz, Susan J.; Moore, Joseph N.; Copp, John F.

    1996-01-24

    Coso is one of several high-temperature geothermal systems on the margins of the Basin and Range province that is associated with recent volcanic activity. This system, which is developed entirely in fractured granitic and metamorphic rocks, consists of a well-defined thermal plume that originates in the southern part of the field and then flows upward and laterally to the north. Fluid inclusion homogenization temperatures and salinities demonstrate that cool, low salinity ground waters were present when the thermal plume was emplaced. Dilution of the thermal waters occurred above and below the plume producing strong gradients in their compositions. In response to heating and mixing, clays and carbonate minerals precipitated, sealing the fractures along the margins of the reservoir and strongly influencing its geometry. The alteration mineralogy varies systematically with depth and temperature. Based on the clay mineralogy, three zones can be recognized: the smectite zone, the illite-smectite zone, and the illite zone. The smectite zone thickens from the north to south and is characterized by smectite, kaolin, stilbite and a variety of carbonate minerals. The illite-smectite zone contains mixed-layer clays and also thickens to the south. The deepest zone (the illite zone) contains illite, chlorite, epidote, and wairakite. Quartz and calcite veins occur in all three zones. Comparison of mineral and fluid inclusion based temperatures demonstrates that cooling has occurred along the margins of the thermal system but that the interior of the system is still undergoing heating.

  20. Deep Groundwater Circulation within Crystalline Basement Rocks and the Role of Hydrologic Windows in the Formation of the Truth or Consequences, New Mexico Low-Temperature Geothermal System

    NASA Astrophysics Data System (ADS)

    Pepin, J.; Person, M. A.; Phillips, F. M.; Kelley, S.; Timmons, S.; Owens, L.; Witcher, J. C.; Gable, C. W.

    2014-12-01

    Hot Springs are common in amagmatic settings, but the mechanisms of heating are often obscure. We have investigated the origin of the Truth or Consequences, New Mexico low-temperature (~ 41 °C) hot springs in the southern Rio Grande rift. We tested two mechanisms that could account for the geothermal anomaly. The first scenario is that the anomaly is the result of lateral forced convection associated with a gently-dipping carbonate aquifer. The second scenario is that high permeability of crystalline basement rocks permits circulation of groundwater down to depths of 8 km prior to discharging in Truth or Consequences. To test these hypotheses, we constructed a two-dimensional hydrothermal model of the region using FEMOC. Model parameters were constrained by calibrating to measured temperatures, specific discharge rates and groundwater residence times. We collected 16 temperature profiles, 11 geochemistry samples and 6 carbon-14 samples within the study area. The geothermal waters are Na+/Cl- dominated and have apparent groundwater ages ranging from 5,500 to 11,500 years. Hot Springs geochemistry is consistent with water/rock interaction in a silicate geothermal reservoir, rather than a carbonate system. Peclet-number analysis of temperature profiles suggests specific discharge rates beneath Truth or Consequences range from 2 to 4 m/year. Geothermometry indicates maximum reservoir temperatures are around 167 °C. We were able to reasonably reproduce observed measurements using the permeable-basement scenario (10-12 m2). The carbonate-aquifer scenario failed to match observations. Our findings imply that the Truth or Consequences geothermal system formed as a result of deep groundwater circulation within permeable crystalline basement rocks. Focused geothermal discharge is the result of localized faulting, which has created a hydrologic window through a regional confining unit. In tectonically active areas, deep groundwater circulation within fractured crystalline basement may play a more prominent role in the formation of geothermal systems than has generally been acknowledged.

  1. Variation in sericite compositions from fracture zones within the Coso Hot Springs geothermal system

    Microsoft Academic Search

    Barbara P. Bishop; Dennis K. Bird

    1987-01-01

    Two types of white micas are found in drillhole samples within the geothermal system at Coso Hot Springs. Low-permeability zones of the crystalline basement contain coarse-grained relict muscovite, whereas rock alteration near fracture zones at temperatures > 150°C is characterized by abundant finegrained sericite in association with secondary calcite and quartz and unaltered relict microcline. In this hydrothermal sericite there

  2. Circulating pump impeller: Presbyterian Intercommunity Hospital, Klamath Falls, Oregon, geothermal heating system. Failure analysis report

    Microsoft Academic Search

    D. A. Mitchell; P. F. Ellis

    1979-01-01

    The Presbyterian Intercommunity Hospital located in Klamath Falls, Oregon utilizes geothermal fluid pumped from its own well to provide space heat and domestic hot water. During an inspection of the heating system after a chemical cleaning of the heat exchangers, the circulating pump was dismantled to replace its seals which were found to be leaking. At that time, the impeller

  3. Geothermal fluxes of alkalinity in the Narayani river system of central Nepal

    E-print Network

    Derry, Louis A.

    Geothermal fluxes of alkalinity in the Narayani river system of central Nepal Matthew J. Evans hot springs flow within the steeply incised gorges of the central Nepal Himalayan front. The spring of central Nepal, Geochem. Geophys. Geosyst., 5, Q08011, doi:10.1029/2004GC000719. G 3 G 3Geochemistry

  4. Assessment of the Enhanced Geothermal System Resource Base of the United States

    Microsoft Academic Search

    David D. Blackwell; Petru T. Negraru; Maria C. Richards

    2006-01-01

    This paper describes an assessment of the enhanced geothermal system (EGS) resource base of the conterminous United States, using constructed temperature at depth maps. The temperature at depth maps were computed from 3 to 10 km, for every km. The methodology is described. Factors included are sediment thickness, thermal conductivity variations, distribution of the radioactive heat generation and surface temperature

  5. Progress toward a stochastic rock mechanics model of engineered geothermal systems

    Microsoft Academic Search

    J. Willis-Richards; K. Watanabe; H. Takahashi

    1996-01-01

    Hot dry rock geothermal energy extraction experiments in artificial reservoirs created by hydraulic stimulation in naturally fractured crystalline rocks have been undertaken in several countries over the last 20 years. The experiments have had mixed results in terms of fluid recovery, system impedance, and heat extraction. Numerical models have not yet delivered a generally agreed understanding of the processes and

  6. Experimentally determined rock-fluid interactions applicable to a natural hot dry rock geothermal system

    SciTech Connect

    Charles, R.W.; Holley, C.E. Jr.; Tester, J.W.; Blatz, L.A.; Grigsby, C.O.

    1980-02-01

    The Los Alamos Scientific Laboratory is pursuing laboratory and field experiments in the development of the Hot Dry Rock concept of geothermal energy. The field program consists of experiments in a hydraulically fractured region of low permeability in which hot rock is intercepted by two wellbores. These experiments are designed to test reservoir engineering parameters such as: heat extraction rates, water loss rates, flow characteristics including impedance and buoyancy, seismic activity and fluid chemistry. Laboratory experiments have been designed to provide information on the mineral reactivity which may be encountered in the field program. Two experimental circulation systems have been built to study the rates of dissolution and alteration in dynamic flow. Solubility studies have been done in agitated systems. To date, pure minerals, samples of the granodiorite from the actual reservoir and Tijeras Canyon granite have been reacted with distilled water and various solutions of NaCl, NaOH, and Na/sub 2/CO/sub 3/. The results of these experimental systems are compared to observations made in field experiments done in a hot dry rock reservoir at a depth of approximately 3 km with initial rock temperatures of 150 to 200/sup 0/C.

  7. Module 7: Geothermal for Agriculture

    NSDL National Science Digital Library

    Eastern Iowa Community College provides this learning module to teach students about sources of geothermal energy, geothermal energy production, components of geothermal systems, potential applications of geothermal energy, and a variety of related topics. Users can download a zip file in which they will find a syllabus, student handouts, a quiz, and 58 slide PowerPoint presentation.

  8. Geothermal energy from the Pannonian Basins System: An outcrop analogue study of exploration target horizons in Hungary

    NASA Astrophysics Data System (ADS)

    Götz, Annette E.; Sass, Ingo; Török, Ákos

    2015-04-01

    The characterization of geothermal reservoirs of deep sedimentary basins is supported by outcrop analogue studies since reservoir characteristics are strongly related to the sedimentary facies and thus influence the basic direction of geothermal field development and applied technology (Sass & Götz, 2012). Petro- and thermophysical rock properties are key parameters in geothermal reservoir characterization and the data gained from outcrop samples serve to understand the reservoir system. New data from the Meso- and Cenozoic sedimentary rocks of Budapest include carbonates and siliciclastics of Triassic, Eocene, Oligocene and Miocene age, exposed on the western side of the river Danube in the Buda Hills (Götz et al., 2014). Field and laboratory analyses revealed distinct horizons of different geothermal potential and thus, enable to identify and interpret corresponding exploration target horizons in geothermal prone depths in the Budapest region as well as in the Hungarian sub-basins of the Pannonian Basins System (Zala and Danube basins, Great Plain) exhibiting geothermal anomalies. References Götz, A.E., Török, Á., Sass, I., 2014. Geothermal reservoir characteristics of Meso- and Cenozoic sedimentary rocks of Budapest (Hungary). German Journal of Geosciences, 165, 487-493. Sass, I., Götz, A.E., 2012. Geothermal reservoir characterization: a thermofacies concept. Terra Nova, 24, 142-147.

  9. Geothermal handbook

    USGS Publications Warehouse

    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 presented which will allow the Service to provide input to the federal leasing process. As an impact information source by which to judge the appropriateness of a specific activity at a specific site, a discussion of activities-impacts is provided on a phase by phase basis. Mitigation and possible enhancement techniques are also presented so that the impacts of the development can be dealt with and the fish and wildlife situation improved. The Service can achieve its objective only if biological input is made throughout the entire process of geothermal development, from exploration to testing to full field operation. A discussion of geothermal leasing procedures emphasizes the timing and nature of Service participation in current interagency lease processing, and there is a provision for the utilization of new knowledge, techniques, and responses as experience is accumulated.

  10. Development of Models to Simulate Tracer Tests for Characterization of Enhanced Geothermal Systems

    SciTech Connect

    Williams, Mark D.; Reimus, Paul; Vermeul, Vincent R.; Rose, Peter; Dean, Cynthia A.; Watson, Tom B.; Newell, D.; Leecaster, Kevin; Brauser, Eric

    2013-05-01

    A recent report found that power and heat produced from enhanced (or engineered) geothermal systems (EGSs) could have a major impact on the U.S energy production capability while having a minimal impact on the environment. EGS resources differ from high-grade hydrothermal resources in that they lack sufficient temperature distribution, permeability/porosity, fluid saturation, or recharge of reservoir fluids. Therefore, quantitative characterization of temperature distributions and the surface area available for heat transfer in EGS is necessary for the design and commercial development of the geothermal energy of a potential EGS site. The goal of this project is to provide integrated tracer and tracer interpretation tools to facilitate this characterization. This project was initially focused on tracer development with the application of perfluorinated tracer (PFT) compounds, non-reactive tracers used in numerous applications from atmospheric transport to underground leak detection, to geothermal systems, and evaluation of encapsulated PFTs that would release tracers at targeted reservoir temperatures. After the 2011 midyear review and subsequent discussions with the U.S. Department of Energy Geothermal Technology Program (GTP), emphasis was shifted to interpretive tool development, testing, and validation. Subsurface modeling capabilities are an important component of this project for both the design of suitable tracers and the interpretation of data from in situ tracer tests, be they single- or multi-well tests. The purpose of this report is to describe the results of the tracer and model development for simulating and conducting tracer tests for characterizing EGS parameters.

  11. Geochemistry of sericite and chlorite in well 14-2 Roosevelt Hot Springs geothermal system and in mineralized hydrothermal systems

    SciTech Connect

    Ballantyne, J.M.

    1980-06-01

    Chemical compositions of chlorite and sericite from one production well in the Roosevelt geothermal system have been determined by electron probe methods and compared with compositions of chlorite and sericite from porphyry copper deposits. Modern system sericite and chlorite occur over a depth interval of 2 km and a temperature interval of 250/sup 0/C.

  12. Geochemistry of sericite and chlorite in well 14-2 Roosevelt Hot Springs geothermal system and in mineralized hydrothermal systems

    Microsoft Academic Search

    Ballantyne

    1980-01-01

    Chemical compositions of chlorite and sericite from one production well in the Roosevelt geothermal system have been determined by electron probe methods and compared with compositions of chlorite and sericite from porphyry copper deposits. Modern system sericite and chlorite occur over a depth interval of 2 km and a temperature interval of 250°C.

  13. Active Management of Integrated Geothermal-CO2 Storage Reservoirs in Sedimentary Formations

    SciTech Connect

    Buscheck, Thomas A.

    2012-01-01

    Active Management of Integrated Geothermal–CO2 Storage Reservoirs in Sedimentary Formations: An Approach to Improve Energy Recovery and Mitigate Risk : FY1 Final Report The purpose of phase 1 is to determine the feasibility of integrating geologic CO2 storage (GCS) with geothermal energy production. Phase 1 includes reservoir analyses to determine injector/producer well schemes that balance the generation of economically useful flow rates at the producers with the need to manage reservoir overpressure to reduce the risks associated with overpressure, such as induced seismicity and CO2 leakage to overlying aquifers. This submittal contains input and output files of the reservoir model analyses. A reservoir-model "index-html" file was sent in a previous submittal to organize the reservoir-model input and output files according to sections of the FY1 Final Report to which they pertain. The recipient should save the file: Reservoir-models-inputs-outputs-index.html in the same directory that the files: Section2.1.*.tar.gz files are saved in.

  14. Application of Microearthquake(MEQ)Monitoring for Characterizing the Performance of Enhanced Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Majer, E.

    2010-12-01

    Microearthquake monitoring for fracture enhancement and imaging of fracture systems will play a crucial role in the success of EGS, both from a reservoir management and public acceptance point of view. One controversial issue associated with EGS is the impact of induced seismicity or microseismicity, which has been the cause of delays and threatened cancellation of at EGS projects worldwide. LBNL is installing, operating , and/or interfacing MEQ seismic arrays at multiple EGS sites which are in collaboration with the USDOE Geothermal EGS Program. The overall goal is to gather high resolution MEQ data before, during and after stimulation activities at the EGS projects. This will include both surface and borehole deployments (as necessary and in conjunction with available boreholes) to not only use MEQ data for understanding the creation and monitoring of fracture stimulation of EGS reservoirs, but for using both active and passive monitoring of the fracture systems. Current EGS DOE Project sites include Desert Peak, Brady’s Hot Springs, and New York Canyon, Nevada, the NW Geysers, and the SE Geysers, California, Raft River, Idaho, and Newberry Caldera in Oregon. A possible additional site in Alaska. Additional sites will be instrumented as DOE adds projects. A second goal is to provide high quality MEQ data, improved processing methodologies to detect and understand fracture and fault mechanics,and advanced analysis of the data to the research community in order to develop, test and apply MEQ methods for understanding the performance of the EGS systems,as well as aid in developing induced seismicity mitigation techniques that can be used for a variety of EGS systems in the future. Reported will be current status and results from the initial injections and how the research community can access the data.

  15. Strategic optimization of large-scale vertical closed-loop shallow geothermal systems

    NASA Astrophysics Data System (ADS)

    Hecht-Méndez, J.; de Paly, M.; Beck, M.; Blum, P.; Bayer, P.

    2012-04-01

    Vertical closed-loop geothermal systems or ground source heat pump (GSHP) systems with multiple vertical borehole heat exchangers (BHEs) are attractive technologies that provide heating and cooling to large facilities such as hotels, schools, big office buildings or district heating systems. Currently, the worldwide number of installed systems shows a recurrent increase. By running arrays of multiple BHEs, the energy demand of a given facility is fulfilled by exchanging heat with the ground. Due to practical and technical reasons, square arrays of the BHEs are commonly used and the total energy extraction from the subsurface is accomplished by an equal operation of each BHE. Moreover, standard designing practices disregard the presence of groundwater flow. We present a simulation-optimization approach that is able to regulate the individual operation of multiple BHEs, depending on the given hydro-geothermal conditions. The developed approach optimizes the overall performance of the geothermal system while mitigating the environmental impact. As an example, a synthetic case with a geothermal system using 25 BHEs for supplying a seasonal heating energy demand is defined. The optimization approach is evaluated for finding optimal energy extractions for 15 scenarios with different specific constant groundwater flow velocities. Ground temperature development is simulated using the optimal energy extractions and contrasted against standard application. It is demonstrated that optimized systems always level the ground temperature distribution and generate smaller subsurface temperature changes than non-optimized ones. Mean underground temperature changes within the studied BHE field are between 13% and 24% smaller when the optimized system is used. By applying the optimized energy extraction patterns, the temperature of the heat carrier fluid in the BHE, which controls the overall performance of the system, can also be raised by more than 1 °C.

  16. Chemical geothermometers and mixing models for geothermal systems

    USGS Publications Warehouse

    Fournier, R.O.

    1977-01-01

    Qualitative chemical geothermometers utilize anomalous concentrations of various "indicator" elements in groundwaters, streams, soils, and soil gases to outline favorable places to explore for geothermal energy. Some of the qualitative methods, such as the delineation of mercury and helium anomalies in soil gases, do not require the presence of hot springs or fumaroles. However, these techniques may also outline fossil thermal areas that are now cold. Quantitative chemical geothermometers and mixing models can provide information about present probable minimum subsurface temperatures. Interpretation is easiest where several hot or warm springs are present in a given area. At this time the most widely used quantitative chemical geothermometers are silica, Na/K, and Na-K-Ca. ?? 1976.

  17. Gas chemistry, boiling and phase segregation in a geothermal system, Hellisheidi, Iceland

    NASA Astrophysics Data System (ADS)

    Scott, Samuel; Gunnarsson, Ingvi; Arnórsson, Stefán; Stefánsson, Andri

    2014-01-01

    The geochemistry of aquifer fluids of the Hellisheidi geothermal system, southwest Iceland, was studied. Based on samples of vapor and liquid from well discharge fluids, the aquifer fluid compositions at the depth of the geothermal system were reconstructed taking into account the highly variable degree of excess well discharge enthalpy, where the enthalpy of the discharge is significantly higher than that of vapor-saturated liquid at the measured aquifer temperature. Decreasing concentrations of non-volatile components such as Si in the total well discharge suggest that the main cause of elevated discharge enthalpies is liquid-vapor phase segregation, i.e. the retention of liquid in the aquifer rock due to its adhesion onto mineral surfaces. Moreover, the slightly lower than equilibrium calculated concentrations of H2 and H2S in some of the hottest and highest-enthalpy wells is considered to be caused by conductive heat transfer from the rocks to the fluids. Alternatively, the cause may lie in the selection of the phase segregation conditions. The calculated concentrations of volatile species in the aquifer fluid are very sensitive to the assumed phase segregation conditions while non-volatiles are not greatly affected by this model parameter. In general, the level of uncertainty does not contradict previous findings of a close approach to fluid-mineral equilibrium at aquifer temperatures above 250 °C. The CO2 concentrations were observed to fall below equilibrium with respect to the most likely mineral buffers, suggesting a possible source control. Elevated H2 concentrations indicate a small equilibrium vapor fraction in aquifer fluids (?0.2% by mass or ?3% by volume). Previous conceptual models of the Hengill volcanic area (e.g. Bödvarsson et al., 1990) have implied a central magmatic heat source underlying the Hengill central volcano. Instead, a new conceptual model of the Hellisheidi system is proposed that features two main regions of fluid upflow heated by a complex of dikes and sills associated with an eruptive fissure active during the Holocene.

  18. Imaging geothermal systems associated with oceanic ridge: first analysis of records from a dense seismic network deployed within and around the Reykjanes high-temperature area, SW-Iceland

    NASA Astrophysics Data System (ADS)

    Jousset, P. G.; Ágústsson, K.; Verdel, A.; Blanck, H.; Stefánsson, S. A.; Erbas, K.; Deon, F.; Erlendsson, Ö.; Guðnason, E. Á.; Specht, S.; Hersir, G. P.; Halldórsdóttir, S.; Wemstraa, K.; Franke, S.; Bruhn, D.; Flovenz, O. G.; Tryggvason, H.; Friðleifsson, G. Ó.

    2014-12-01

    Manifestations of supercritical water in magmatic environments have so far only been accessible from analogue outcrops of fossil systems and by simulating pressure/temperature conditions in the laboratory. In order to assess the unknown properties of such reservoirs, scientific drilling is used when Earth surface sampled rocks cannot sufficiently explain past geological processes and when geophysical imaging does not sufficiently explain observed phenomena. However, our understanding of structural and dynamic characteristics of geothermal systems can be improved through application of advanced and/or innovative exploration technologies. Unlike resistivity imaging, active and passive seismic techniques have rarely been used in volcanic geothermal areas, because processing techniques were not adapted to geothermal conditions. Recent advances in volcano-seismology have introduced new processing techniques for assessing subsurface structures and controls on fluid flow in geothermal systems. We present here preliminary analyses of seismic records around a geothermal reservoir located both on-land and offshore along the Reykjanes Ridge, SW-Iceland. We deployed on-land stations (20 broad-band and 10 short-period seismometers) and 24 Ocean Bottom Seismometers which are recording since April 2014. Together with existing permanent stations, the complete network comprises 66 stations. The network was designed so that several processing techniques can be used with the data set and address scientific questions concerning geothermal systems and the oceanic ridge. We present the network deployment, our approach and preliminary results from the first months.

  19. Application of Fusion Gyrotrons to Enhanced Geothermal Systems (EGS)

    NASA Astrophysics Data System (ADS)

    Woskov, P.; Einstein, H.; Oglesby, K.

    2013-10-01

    The potential size of geothermal energy resources is second only to fusion energy. Advances are needed in drilling technology and heat reservoir formation to realize this potential. Millimeter-wave (MMW) gyrotrons and related technologies developed for fusion energy research could contribute to enabling EGS. Directed MMW energy can be used to advance rock penetration capabilities, borehole casing, and fracking. MMWs are ideally suited because they can penetrate through small particulate extraction plumes, can be efficiently guided long distances in borehole dimensions, and continuous megawatt sources are commercially available. Laboratory experiments with a 10 kW, 28 GHz CPI gyrotron have shown that granite rock can be fractured and melted with power intensities of about 1 kW/cm2 and minute exposure times. Observed melted rock MMW emissivity and estimated thermodynamics suggest that penetrating hot, hard crystalline rock formations may be economic with fusion research developed MMW sources. The potential size of geothermal energy resources is second only to fusion energy. Advances are needed in drilling technology and heat reservoir formation to realize this potential. Millimeter-wave (MMW) gyrotrons and related technologies developed for fusion energy research could contribute to enabling EGS. Directed MMW energy can be used to advance rock penetration capabilities, borehole casing, and fracking. MMWs are ideally suited because they can penetrate through small particulate extraction plumes, can be efficiently guided long distances in borehole dimensions, and continuous megawatt sources are commercially available. Laboratory experiments with a 10 kW, 28 GHz CPI gyrotron have shown that granite rock can be fractured and melted with power intensities of about 1 kW/cm2 and minute exposure times. Observed melted rock MMW emissivity and estimated thermodynamics suggest that penetrating hot, hard crystalline rock formations may be economic with fusion research developed MMW sources. Supported by USDOE, Office of Energy Efficiency and Renewable Energy and Impact Technologies, LLC.

  20. Iceland is a country of breathtaking natural beauty, geothermal activity and volcanoes that, as we all know by

    E-print Network

    Tradacete, Pedro

    Iceland is a country of breathtaking natural beauty, geothermal activity and volcanoes that, as we and informative, survey of the research work in computer science that is going on "under the volcano". I, Volcanoes and... Computer Science! 27-10-2010 14:00 Sala de Grados Facultad de Informática Luca Aceto

  1. Current California legislative and regulatory activity impacting geothermal hydrothermal commercialization: monitoring report No. 2. Report No. 1020

    SciTech Connect

    Not Available

    1980-04-20

    The progress of four bills relating to geothermal energy is reported. The current regulatory activities of the California Energy Commission, the Lake County Planning Commission/Lake County Air Pollution Control District, the Governor's Office of Planning and Research, the State Lands' Commission, and the California Public Utilities Commission are reviewed. (MHR)

  2. GEOGRAPHIC INFORMATION SYSTEMS IN MANAGING OF TERRITORIAL RESOURCES: AN EXAMPLE FOR THE SABATINI GEOTHERMAL SYSTEM (CENTRAL ITALY)

    NASA Astrophysics Data System (ADS)

    Procesi, M.; Cinti, D.; Poncia, P.; de Rita, D.

    2009-12-01

    Geographic Information System (GIS) is very important tool in managing the interdisciplinary researches and territorial resources. GIS integrates data for capturing, managing, analyzing, and displaying all forms of geographically referenced information. They can represent a scientific and social benefit. Here we present an application of GIS to a potentially exploitable geothermal area. The geothermal resource can be used either indirectly or directly. In the first case electricity is produced from high enthalpy systems. In second case heating and cooling systems are obtained from medium or low enthalpy systems. Italian geothermal resources employment is still poorly developed in direct use sector, despite the great geothermal potentials suitable for this purpuse. Often this limited application is due mainly to a inadequate territory knowledge and sometimes by difficulties in obtaining required information. In this case the creation of a geo-database can be extremely helpful. The studied area is located in Central Italy, just north of Rome, and comprise the western part of the Sabatini Volcanic District, Tolfa Mountains, extending up to Civitavecchia. Exploration surveys investigated this area during 70’s-90’s for geothermal purpose, but the area still results unexploited. The presence of thermal waters and of anomalous heat flow, together with demographical growing of the last years, make this site a suitable location for direct applications of the geothermal resource. Previews work and new data about geological, structural, hydrogeological, geochemical features have been processed to be recorded in a geo-database . Further, social data about demographical trend and available scientific record concerning the studied area fulfill the database. The majority of available geological information date back to early 90’s; an important part of the work consisted in the digitalization and updating of pre-existent data. The final product is a WEB-GIS that can facilitate diffusion and consultation of geographically referenced data, which can be easily managed by public and private infrastructures, research institutes and universities, allowing a better development of the territorial resources.

  3. Modeling of thermodynamic and chemical changes in low-temperature geothermal systems

    SciTech Connect

    Spencer, A.L.

    1986-12-01

    A method was developed to incorporate the transport of several chemical components into a model of the transport of fluid mass and heat within a geothermal system. It was demonstrated that the use of coupled hydrological, thermal and chemical data allows for the determination of field porosities, amounts and regions of cool recharge into the system as well as field permeabilities and the hot reservoir volume. With the additional information a reliable prediction of the long-term cooling rate can be made.

  4. GTO-DOE/Industry Cost Shared Research; Microseismic Characterization and Monitoring in Geothermal Systems

    SciTech Connect

    Majer, E.L.

    1989-03-21

    The application of passive seismic studies in geothermal regions have undergone significant changes in the last 15 years. The primary application is now in the monitoring of subsurface processes, rather than exploration. A joint Geothermal Technology Organization (GTO) industry/DOE, monitoring project involving GEO, Unocal Geothermal, and LBL, was carried out at The Geysers geothermal field in northern California using a special high frequency monitoring system. This several-month-long experiment monitored the discrete and continuous seismic signals before, during, and after a fluid stimulation of a marginal production well. Almost 350,000 liters of water were pumped into the well over a four-hour, and a three-hour time period for two consecutive days in June of 1988. No significant changes in the background seismicity or the seismic noise were detected during the monitoring period. Analysis of the background seismicity did indicate that the earthquakes at The Geysers contain frequencies higher than 50 Hz. and possibly as high as 100 Hz.

  5. Advanced Horizontal Well Recirculation Systems for Geothermal Energy Recovery in Sedimentary Formations

    SciTech Connect

    Mike Bruno; Russell L. Detwiler; Kang Lao; Vahid Serajian; Jean Elkhoury; Julia Diessl; Nicky White

    2012-09-30

    There is increased recognition that geothermal energy resources are more widespread than previously thought, with potential for providing a significant amount of sustainable clean energy worldwide. Recent advances in drilling, completion, and production technology from the oil and gas industry can now be applied to unlock vast new geothermal resources, with some estimates for potential electricity generation from geothermal energy now on the order of 2 million megawatts. Terralog USA, in collaboration with the University of California, Irvine (UCI), are currently investigating advanced design concepts for paired horizontal well recirculation systems, optimally configured for geothermal energy recovery in permeable sedimentary and crystalline formations of varying structure and material properties. This two-year research project, funded by the US Department of Energy, includes combined efforts for: 1) Resource characterization; 2) Small and large scale laboratory investigations; 3) Numerical simulation at both the laboratory and field scale; and 4) Engineering feasibility studies and economic evaluations. The research project is currently in its early stages. This paper summarizes our technical approach and preliminary findings related to potential resources, small-scale laboratory simulation, and supporting numerical simulation efforts.

  6. IGA: International Geothermal Association

    NSDL National Science Digital Library

    The International Geothermal Association's (IGA) goal is "to encourage research, development, and utilization of geothermal resources worldwide through the compilation, publication, and dissemination of scientific and technical data and information." The website offers a multitude of information about geothermal energy around the world. Students can find educational resources about the history, nature, classification, utilization, and exploration of geothermal systems. Through an interactive map, users can find data on geothermal energy. Researchers can discover journals and upcoming conferences. Visitors can also learn how to take part in the IGA panel and discussion group.

  7. Fracture sealing in geothermal systems: A combined EBSD and chemical approach

    NASA Astrophysics Data System (ADS)

    Mcnamara, D. D.; Lister, A.; Prior, D. J.; Brenna, M.

    2014-12-01

    Development of natural and enhanced geothermal resources hosted in crystalline, volcanic and plutonic reservoir rocks, or in indurated, metamorphic basement reservoirs has increased over recent years. In these reservoir rocks, permeability is dominated by faults and fractures, with small contributions made by primary permeability. As such the study of how these structures are generated, their properties (e.g. orientation, spatial distribution, aperture, orientation with respect to the stress field), and how they become filled with precipitated minerals is vital to understanding the evolution of these geothermal systems, and is key to their successful development. In particular, fracture sealing is known to decrease the overall permeability of, or create permeability barriers in a geothermal reservoir, limiting its effectiveness as a resource. As such study of this sealing process is vital to discerning the evolution of fractured geothermal systems. We use electron backscatter diffraction combined with cathodoluminescence and energy dispersive X-ray data from calcite and quartz filled veins from high temperature geothermal fields in New Zealand to investigate chemical patterns and microstructures in sealed reservoir fractures. Results indicate that while chemical zonation patterns may appear diverse or complicated, accompanying physical mineral growth and microstructure can either be simple or tell a more convoluted story. Calcite veins explored show little to no deformation and chemical suggesting postkinematic vein growth into free space with no subsequent deformation, while chemical zonation suggests fluid chemistry variation as sealing progressed. Quartz filled veins show crystal orientation of depositing vein crystals is controlled by that of the fracture wall minerals, and that varying chemistry has little to no impact on quartz microstructure.

  8. Potential for a significant deep basin geothermal system in Tintic Valley, Utah

    NASA Astrophysics Data System (ADS)

    Hardwick, C.; Kirby, S.

    2014-12-01

    The combination of regionally high heat flow, deep basins, and permeable reservoir rocks in the eastern Great Basin may yield substantial new geothermal resources. We explore a deep sedimentary basin geothermal prospect beneath Tintic Valley in central Utah using new 2D and 3D models coupled with existing estimates of heat flow, geothermometry, and shallow hydrologic data. Tintic Valley is a sediment-filled basin bounded to the east and west by bedrock mountain ranges where heat-flow values vary from 85 to over 240 mW/m2. Based on modeling of new and existing gravity data, a prominent 30 mGal low indicates basin fill thickness may exceed 2 km. The insulating effect of relatively low thermal conductivity basin fill in Tintic Valley, combined with typical Great Basin heat flow, predict temperatures greater than 150 °C at 3 km depth. The potential reservoir beneath the basin fill is comprised of Paleozoic carbonate and clastic rocks. The hydrology of the Tintic Valley is characterized by a shallow, cool groundwater system that recharges along the upper reaches of the basin and discharges along the valley axis and to a series of wells. The east mountain block is warm and dry, with groundwater levels just above the basin floor and temperatures >50 °C at depth. The west mountain block contains a shallow, cool meteoric groundwater system. Fluid temperatures over 50 °C are sufficient for direct-use applications, such as greenhouses and aquaculture, while temperatures exceeding 140°C are suitable for binary geothermal power plants. The geologic setting and regionally high heat flow in Tintic Valley suggest a geothermal resource capable of supporting direct-use geothermal applications and binary power production could be present.

  9. Development of an Enhanced Two-Phase Production System at the Geysers Geothermal Field

    SciTech Connect

    Steven Enedy

    2001-12-14

    A method was developed to enhance geothermal steam production from two-phase wells at THE Geysers Geothermal Field. The beneficial result was increased geothermal production that was easily and economically delivered to the power plant.

  10. Recent drilling activities at the earth power resources Tuscarora geothermal power project's hot sulphur springs lease area.

    SciTech Connect

    Goranson, Colin

    2005-03-01

    Earth Power Resources, Inc. recently completed a combined rotary/core hole to a depth of 3,813 feet at it's Hot Sulphur Springs Tuscarora Geothermal Power Project Lease Area located 70-miles north of Elko, Nevada. Previous geothermal exploration data were combined with geologic mapping and newly acquired seismic-reflection data to identify a northerly tending horst-graben structure approximately 2,000 feet wide by at least 6,000 feet long with up to 1,700 feet of vertical offset. The well (HSS-2) was successfully drilled through a shallow thick sequence of altered Tertiary Volcanic where previous exploration wells had severe hole-caving problems. The ''tight-hole'' drilling problems were reduced using drilling fluids consisting of Polymer-based mud mixed with 2% Potassium Chloride (KCl) to reduce Smectite-type clay swelling problems. Core from the 330 F fractured geothermal reservoir system at depths of 2,950 feet indicated 30% Smectite type clays existed in a fault-gouge zone where total loss of circulation occurred during coring. Smectite-type clays are not typically expected at temperatures above 300 F. The fracture zone at 2,950 feet exhibited a skin-damage during injection testing suggesting that the drilling fluids may have caused clay swelling and subsequent geothermal reservoir formation damage. The recent well drilling experiences indicate that drilling problems in the shallow clays at Hot Sulphur Springs can be reduced. In addition, average penetration rates through the caprock system can be on the order of 25 to 35 feet per hour. This information has greatly reduced the original estimated well costs that were based on previous exploration drilling efforts. Successful production formation drilling will depend on finding drilling fluids that will not cause formation damage in the Smectite-rich fractured geothermal reservoir system. Information obtained at Hot Sulphur Springs may apply to other geothermal systems developed in volcanic settings.

  11. U-Th dating of vein calcite by LA-MC-ICP-MS: preliminary results from geothermal systems

    NASA Astrophysics Data System (ADS)

    McGee, L. E.; Reich, M.; Rodriguez, V.; Leisen, M.; Barra, F.

    2014-12-01

    The measurement of U-series isotopes in precipitated minerals such as calcite holds various challenges, including low U and Th concentrations (in the ppb-ppt range), and the presence of detrital 232Th which can lead to age overestimations. Additionally, as yet there does not exist a calcite standard reference material for inter-laboratory accuracy and precision comparison, with most laboratories using their own in-house standard material and focussing largely on application to paleoclimate studies (e.g. corals and speleothems). In actively deforming regions, high-pressure hydrothermal fluids play an important role in faulting and vein formation, and commonly fault rupture is followed by rapid sealing through mineral precipitation. Therefore, precise dating of vein growth is of special importance to our understanding of the complex interplay between seismic events and fluid flow in the upper crust, and opens up a new field of study using U-Th techniques. The ability to accurately date fault-filling calcite within such settings has the power to elucidate the connection between structure and fluid flow in the development of geothermal systems, and provide valuable information on the longevity of the heat/water source, in addition to regional magmatic history. We are developing U-Th measurements and ages of vein calcite from geothermal systems using a Neptune Plus MC-ICP-MS (with 5 CDDs and 3 SEMs) coupled to an excimer 193nm Photon Machines laser. We will be comparing our results with an 189ka in-house flowstone calcite standard previously dated by TIMS, as well as developing a geothermal calcite standard.

  12. Effect of geothermal waste on strength and microstructure of alkali-activated slag cement mortars

    SciTech Connect

    Escalante-Garcia, J.I.; Gorokhovsky, A.V.; Mendoza, G.; Fuentes, A.F

    2003-10-01

    Mortars of blast furnace slag replaced with 10% of a geothermal silica waste were cured for 90 days. The binder was activated by 6 wt.% Na{sub 2}O equivalent of NaOH and water glass. The presence of the silica enhanced the formation of hydration products as shown by nonevaporable water (NEW) results. Backscattered electron images indicated that the microstructures of blended slag had less porosity than those of neat slag mortars and the interfacial zone between aggregate and hydration products was dense and of homogeneous composition similar to the matrix of hydration products. The main hydration products were C-S-H and for NaOH a hydrotalcite type phase was found as finely intermixed with the C-S-H.

  13. THERMO-HYDRO-MECHANICAL SIMULATION OF GEOTHERMAL

    E-print Network

    Politècnica de Catalunya, Universitat

    THERMO-HYDRO-MECHANICAL SIMULATION OF GEOTHERMAL RESERVOIR STIMULATIONRESERVOIR STIMULATION Silvia Seminario del Grupo de Hidrologìa Subterrànea - UPC, Barcelona #12;INTRODUCTION Enhanced geothermal systems Geothermal gradient ~ 33 °C/Km Hydraulic stimulation enhances fracture permeability (energy

  14. Geothermal Energy.

    ERIC Educational Resources Information Center

    Eaton, William W.

    Described are the origin and nature of geothermal energy. Included is the history of its development as an energy source, technological considerations affecting its development as an energy source, its environmental effects, economic considerations, and future prospects of development in this field. Basic system diagrams of the operation of a…

  15. Review of international geothermal activities and assessment of US industry opportunities: Summary report

    SciTech Connect

    Not Available

    1987-08-01

    This report summarizes a study initiated to review and assess international developments in the geothermal energy field and to define business opportunities for the US geothermal industry. The report establishes data bases on the status of worldwide geothermal development and the competitiveness of US industry. Other factors identified include existing legislation, tax incentives, and government institutions or agencies and private sector organizations that promote geothermal exports. Based on the initial search of 177 countries and geographic entities, 71 countries and areas were selected as the most likely targets for the expansion of the geothermal industry internationally. The study then determined to what extent their geothermal resource had been developed, what countries had aided or participated in this development, and what plans existed for future development. Data on the energy, economic, and financial situations were gathered.

  16. Geothermal energy: 1992 program overview

    SciTech Connect

    Not Available

    1993-04-01

    Geothermal energy is described in general terms with drawings illustrating the technology. A map of known and potential geothermal resources in the US is included. The 1992 program activities are described briefly. (MHR)

  17. Underground Mine Water Heating and Cooling Using Geothermal Heat Pump Systems

    SciTech Connect

    Watzlaf, G.R.; Ackman, T.E.

    2006-03-01

    In many regions of the world, flooded mines are a potentially cost-effective option for heating and cooling using geothermal heat pump systems. For example, a single coal seam in Pennsylvania, West Virginia, and Ohio contains 5.1 x 1012 L of water. The growing volume of water discharging from this one coal seam totals 380,000 L/min, which could theoretically heat and cool 20,000 homes. Using the water stored in the mines would conservatively extend this option to an order of magnitude more sites. Based on current energy prices, geothermal heat pump systems using mine water could reduce annual costs for heating by 67% and cooling by 50% over conventional methods (natural gas or heating oil and standard air conditioning).

  18. Enhanced Geothermal Systems Project Development Solicitation - Final Report - 09/30/2000 - 02/01/2001

    SciTech Connect

    Nielson, Dennis L.

    2001-05-07

    The Enhanced Geothermal System concept is to develop the technology required to extract energy from the reduced permeability zones that underlie all high-temperature geothermal systems. Our concept is that injection wells will be drilled into the high temperature zone. The wells will identify fractures that are only poorly connected to the overlying reservoir. Water injected into these fractures will cause them to propagate through thermal contraction, increase in hydrostatic pressure, and reduction of effective stress. The fractures will connect with the overlying normal temperature reservoir, and steam will be produced from existing production wells. The injection water will generate high thermal quality steam while mitigating problems relating to high gas and chloride.

  19. Experience with the EM-60 electromagnetic system for geothermal exploration in Nevada

    SciTech Connect

    Wilt, M.; Goldstein, N.E.; Stark, M.; Haught, J.R.; Morrison, H.F.

    1981-09-01

    Lawrence Berkeley Laboratory (LBL) conducted controlled-source electromagnetic (EM) surveys at three geothermal prospects in northern Nevada. Over 40 soundings were made in Panther Canyon (Grass Valley), near Winnemucca; Soda Lakes, near Fallon; and McCoy, west of Austin, to test and demonstrate the applicability of LBL's EM-60 system to geothermal exploration. The EM-60 is a frequency-domain system using three-component magnetic detection. Typically, +-65 A is applied to an 100-m-diameter four-turn horizontal loop, generating a dipole moment >10/sup 6/ MKS over the frequency range 10/sup -3/ to 10/sup -3/ Hz. With such a source loop, soundings were made, at transmitter-receiver separations of up to 4 km, providing a maximum depth of penetration of 4 km.

  20. Low-Temperature Enhanced Geothermal System using Carbon Dioxide as the Heat-Transfer Fluid

    SciTech Connect

    Eastman, Alan D. [GreenFire Energy

    2014-07-24

    This report describes work toward a supercritical CO2-based EGS system at the St. Johns Dome in Eastern Arizona, including a comprehensive literature search on CO2-based geothermal technologies, background seismic study, geological information, and a study of the possible use of metal oxide heat carriers to enhance the heat capacity of sCO2. It also includes cost estimates for the project, and the reasons why the project would probably not be cost effective at the proposed location.

  1. Underground Mine Water for Heating and Cooling using Geothermal Heat Pump Systems

    Microsoft Academic Search

    George R. Watzlaf; Terry E. Ackman

    2006-01-01

    In many regions of the world, flooded mines are a potentially cost-effective option for heating and cooling using geothermal\\u000a heat pump systems. For example, a single coal seam in Pennsylvania, West Virginia, and Ohio contains 5.1 x 1012 L of water. The growing volume of water discharging from this one coal seam totals 380,000 L\\/min, which could theoretically\\u000a heat and

  2. Assessment of the Enhanced Geothermal System Resource Base of the United States

    Microsoft Academic Search

    David D. Blackwell; Petru T. Negraru; Maria C. Richards

    2006-01-01

    This paper describes an assessment of the enhanced geothermal system (EGS) resource base of the conterminous United States,\\u000a using constructed temperature at depth maps. The temperature at depth maps were computed from 3 to 10 km, for every km. The\\u000a methodology is described. Factors included are sediment thickness, thermal conductivity variations, distribution of the radioactive\\u000a heat generation and surface temperature based

  3. A re-evaluation of the Moyuta geothermal system, Southern Guatemala

    Microsoft Academic Search

    F. Goff; A. Adams; P. E. Trujillo; D. Counce; C. Janik; L. Fahlquist; A. Roldan; M. Revolorio

    1991-01-01

    Chemical and isotopic data from four fumarole sites combined with prefeasibility assessments obtained in the 1970s have resulted in a re-evaluation of the Moyuta geothermal system. Moyuta consists of an east-west trending complex of Quaternary andesite\\/dacite domes and flows cut by north-trending faults. Areas of fumaroles, acid springs, and bicarbonate-rich thermal springs flank the north and south sides of the

  4. Geothermal systems of the Mono Basin-Long Valley region, eastern California and western Nevada

    SciTech Connect

    Higgins, C.T.; Flynn, T.; Chapman, R.H.; Trexler, D.T.; Chase, G.R.; Bacon, C.F.; Ghusn, G. Jr.

    1985-01-01

    The region that includes Mono Basin, Long Valley, the Bridgeport-Bodie Hills area, and Aurora, in eastern California and western Nevada was studied to determine the possible causes and interactions of the geothermal anomalies in the Mono Basin-Long Valley region as a whole. A special goal of the study was to locate possible shallow bodies of magma and to determine their influence on the hydrothermal systems in the region. (ACR)

  5. Development of the well trajectory prediction system as a part of the MWD system for geothermal wells

    SciTech Connect

    Nakashima, S.; Nakata, H.; Takasugi, S. [Geothermal Energy Research and Development Co., Ltd., Tokyo (Japan)

    1995-12-31

    MWD (Measurement while drilling) system for geothermal wells has been developed by NEDO (the New Energy and Industrial Technology Development Organization) since 1991. As a part of this system, the drilling support system has been also developed. The well trajectory prediction system is one of this drilling support system including the well trajectory planning system, the well trajectory visualization system, the temperature analysis system and so on, and this system will be used for prediction of well trajectory while drilling and for design of BHA (bottom hole assembly) before drilling. We discussed about the theory of the well trajectory prediction system and its case studies in this paper.

  6. Simulation of water-rock interaction in the yellowstone geothermal system using TOUGHREACT

    SciTech Connect

    Dobson, P.F.; Salah, S.; Spycher, N.; Sonnenthal, E.

    2003-04-28

    The Yellowstone geothermal system provides an ideal opportunity to test the ability of reactive transport models to accurately simulate water-rock interaction. Previous studies of the Yellowstone geothermal system have characterized water-rock interaction through analysis of rocks and fluids obtained from both surface and downhole samples. Fluid chemistry, rock mineralogy, permeability, porosity, and thermal data obtained from the Y-8 borehole in Upper Geyser Basin were used to constrain a series of reactive transport simulations of the Yellowstone geothermal system using TOUGHREACT. Three distinct stratigraphic units were encountered in the 153.4 m deep Y-8 drill core: volcaniclastic sandstone, perlitic rhyolitic lava, and nonwelded pumiceous tuff. The main alteration phases identified in the Y-8 core samples include clay minerals, zeolites, silica polymorphs, adularia, and calcite. Temperatures observed in the Y-8 borehole increase with depth from sub-boiling conditions at the surface to a maximum of 169.8 C at a depth of 104.1 m, with near-isothermal conditions persisting down to the well bottom. 1-D models of the Y-8 core hole were constructed to determine if TOUGHREACT could accurately predict the observed alteration mineral assemblage given the initial rock mineralogy and observed fluid chemistry and temperatures. Preliminary simulations involving the perlitic rhyolitic lava unit are consistent with the observed alteration of rhyolitic glass to form celadonite.

  7. A hydrogeological and geochemical model of the high-temperature geothermal system of Amatitlan, Guatemala

    SciTech Connect

    Lima, E.; Fujino, T. [West Japan Engineering Consultants, Inc., Fukuoka (Japan); McNitt, J.R.; Klein, C.W. [GeothermEx, Inc., Richmond, CA (United States)] [and others

    1996-12-31

    Geological, geophysical and geochemical data from deep and shallow wells indicate the presence of a large geothermal system fed by upflow beneath Volcan de Pacaya, with source temperatures {ge} 330{degrees}C and chloride contents on the order of 2,500 mg/l. A considerable contribution of magmatic water is suggested by chemical and isotopic data, provided that water-rock interactions have substantially neutralized the acidity of the magmatic component. The areal extent of the upflow zone is unknown, and can only be delimited by further drilling to the south and southeast of deep well AMF-2, which encounters the two-phase upflow zone. Outflow is directed to the north, towards Lago de Amatitlan. The outflow path is long (more than 7 km), and lateral cooling occurs both via conduction and dilution with cool groundwater. Vertical cooling is also indicated by temperature reversals of up to 60{degrees}C beneath the outflow tongue, attributed to a regional underflow of cool groundwater. Outflow paths do not appear to be controlled by geologic structures or aquifers; instead, the hot water appears to {open_quotes}float{close_quotes} on top of the gently sloping unconfined groundwater table. These aspects of the geothermal system were used to develop the numerical model of the Amatitlan geothermal system, which is the subject of a separate paper.

  8. Simulation of water-rock interaction in the Yellowstone geothermal system using TOUGHREACT

    SciTech Connect

    Dobson, Patrick F.; Salah, Sonia; Spycher, Nicolas; Sonnenthal, Eric L.

    2003-04-28

    The Yellowstone geothermal system provides an ideal opportunity to test the ability of reactive transport models to simulate the chemical and hydrological effects of water-rock interaction. Previous studies of the Yellowstone geothermal system have characterized water-rock interaction through analysis of rocks and fluids obtained from both surface and downhole samples. Fluid chemistry, rock mineralogy, permeability, porosity, and thermal data obtained from the Y-8 borehole in Upper Geyser Basin were used to constrain a series of reactive transport simulations of the Yellowstone geothermal system using TOUGHREACT. Three distinct stratigraphic units were encountered in the 153.4 m deep Y-8 drill core: volcaniclastic sandstone, perlitic rhyolitic lava, and nonwelded pumiceous tuff. The main alteration phases identified in the Y-8 core samples include clay minerals, zeolites, silica polymorphs, adularia, and calcite. Temperatures observed in the Y-8 borehole increase with depth from sub-boiling conditions at the surface to a maximum of 169.8 C at a depth of 104.1 m, with near-isothermal conditions persisting down to the well bottom. 1-D models of the Y-8 core hole were constructed to simulate the observed alteration mineral assemblage given the initial rock mineralogy and observed fluid chemistry and temperatures. Preliminary simulations involving the perlitic rhyolitic lava unit are consistent with the observed alteration of rhyolitic glass to form celadonite.

  9. Hydrothermal fluids vented at shallow depths at the Aeolian islands: relationships with volcanic and geothermal systems.

    NASA Astrophysics Data System (ADS)

    Italiano, Francesco; Caracausi, Antonio; Longo, Manfredi; Maugeri, Roberto; Paonita, Antonio

    2010-05-01

    Scuba diving investigations carried out over the last two decades at the Aeolian islands revealed the existence of submarine magmatic and late-magmatic hydrothermalism at all the islands, despite the absence of on-shore activity at some of the islands. The results gained by diving activities provided useful information to evaluate the volcanic and geothermal activity and to manage the volcanic crisis occurred on November 2002 off the island of Panarea. Scuba diving investigations carried out from middle 80's, had shown that despite the absence of on shore volcanic manifestations, submarine hydrothermal activity is recognizable at shallow depth around all the Aeolian islands related either to volcanic and geothermal activity. The sampled gases are CO2-dominated with low amounts of oxygen and reactive gases (H2, CO, CH4 and H2S) with concentrations ranging from a few ppm to some mole percent. Sometimes significant N2 amount are detectable together with high helium contents. Samples having low CO2 content, besides relevant N2 and He amounts, are the consequence of CO2 dissolution in sea-water due to gas-water interactions (GWI) occurred before the sample collection. The high CO2 solubility (878 ml/l, T=20°C, P=1bar) may, in fact, decrease the CO2 content in the venting gases thus increasing the concentrations of the less soluble species (e.g. He 8 ml/l, CO 23 ml/l and CH4 33.8 ml/l) in the gas mixture. Such a process might occur at any level, however, because of the slow water circulation in deep sediments, CO2 is able to saturate the circulating sea-water. The isotopic composition of carbon displays a small range of values while helium isotopes are in the range of 4.1active and extinct Volcanoes, their chemical composition is similar. Contrastingly the isotope composition of helium shows a large heterogeneity with the highest isotopic ratios surprisingly measured at the extinct volcanic islands in the western sector, and much lower values detected in venting gases from active volcanoes (e.g. Vulcano and Panarea). The explanation of such a difference is not related to the volcanic activity at all, but to the parent mantle that in the western side looks to be less contaminated compared to the eastern side. Crustal contamination has been invoked by several authors as the main factor that caused the dramatic 3He/4He decrease. Although the parent mantle produced magmas with different isotopic signature, the gas phase looks similar. To explain the results of the chemical analyses it is proposed that similar deep boundary conditions (pressure, temperature, oxidation level) act as buffers for the chemical composition of the venting gases. With the aim of investigating their origin, estimations of the deep equilibration conditions have been carried out. The reactive compounds detected in the sampled gases, largely used for geothermometric and geobarometric considerations of hydrothermal fluids were used in a system based on the CH4-CO-CO2 contents assuming the presence of a boiling aqueous solution. The equilibrium constants of the adopted reactions are a function of temperature and oxygen fugacity, being the latter buffered by the mineral assemblage of the host rocks. Due to the similarity in the chemical composition of the gases vented at all the islands, a theoretical model developed to interpret the chemical composition of the gases released at Panarea during the last volcanic crisis is here applied. The results have shown that geothermal boiling systems are detectable at all the islands with temperatures up to 350°C. The adopted geo-thermobarometric system is more sensitive to the contents of CO and CH4 than that of CO2, implying that although GWI induce modifications in the chemical composition, the estimated equilibrium temperatures do not change very much for variations of the CO2 content in the range of several volume percent, thus, whether or not the gaseous mixture underwent GWI. Moreover, the slow reaction kinetics of CO and CH4 allow them to keep the deep equilibrium c

  10. Pumpernickel Valley Geothermal Project Thermal Gradient Wells

    SciTech Connect

    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, -2, -3, and -4, and all four encountered geothermal fluids. The holes provided valuable water geochemistry, supporting the geothermometry results obtained from the hot springs and Magma well. The temperature data gathered from all the wells clearly indicates the presence of a major plume of thermal water centered on the Pumpernickel Valley fault, and suggests that the main plume is controlled, at least in part, by flow from this fault system. The temperature data also defines the geothermal resource with gradients >100oC/km, which covers an area a minimum of 8 km2. Structural blocks, down dropped with respect to the Pumpernickel Valley fault, may define an immediate reservoir. The geothermal system almost certainly continues beyond the recently drilled holes and might be open to the east and south, whereas the heat source responsible for the temperatures associated with this plume has not been intersected and must be at a depth greater than 920 meters (depth of the deepest well – Magma well). The geological and structural setting and other characteristics of the Pumpernickel Valley geothermal project area are markedly similar to the portions of the nearby Dixie Valley geothermal field. These similarities include, among others, the numerous, unexposed en echelon faults and large-scale pull-apart structure, which in Dixie Valley may host part of the geothermal field. The Pumpernickel Valley project area, for the majority of which Nevada Geothermal Power Company has geothermal rights, represents a geothermal site with a potential for the discovery of a relatively high temperature reservoir suitable for electric power production. Among locations not previously identified as having high geothermal potential, Pumpernickel Valley has been ranked as one of four sites with the highest potential for electrical power production in Nevada (Shevenell and Garside, 2003). Richards and Blackwell (2002) estimated the total heat loss and the preliminary production capacity for the entire Pumpernickel Valley geothermal system to be at 35MW. A more conservative estimate, for

  11. Ground heat flux and power sources of low-enthalpy geothermal systems

    NASA Astrophysics Data System (ADS)

    Bayer, Peter; Blum, Philipp; Rivera, Jaime A.

    2015-04-01

    Geothermal heat pumps commonly extract energy from the shallow ground at depths as low as approximately 400 m. Vertical borehole heat exchangers are often applied, which are seasonally operated for decades. During this lifetime, thermal anomalies are induced in the ground and surface-near aquifers, which often grow over the years and which alleviate the overall performance of the geothermal system. As basis for prediction and control of the evolving energy imbalance in the ground, focus is typically set on the ground temperatures. This is reflected in regulative temperature thresholds, and in temperature trends, which serve as indicators for renewability and sustainability. In our work, we examine the fundamental heat flux and power sources, as well as their temporal and spatial variability during geothermal heat pump operation. The underlying rationale is that for control of ground temperature evolution, knowledge of the primary heat sources is fundamental. This insight is also important to judge the validity of simplified modelling frameworks. For instance, we reveal that vertical heat flux from the surface dominates the basal heat flux towards a borehole. Both fluxes need to be accounted for as proper vertical boundary conditions in the model. Additionally, the role of horizontal groundwater advection is inspected. Moreover, by adopting the ground energy deficit and long-term replenishment as criteria for system sustainability, an uncommon perspective is adopted that is based on the primary parameter rather than induced local temperatures. In our synthetic study and dimensionless analysis, we demonstrate that time of ground energy recovery after system shutdown may be longer than what is expected from local temperature trends. In contrast, unrealistically long recovery periods and extreme thermal anomalies are predicted without account for vertical ground heat fluxes and only when the energy content of the geothermal reservoir is considered.

  12. Materials for geothermal production

    SciTech Connect

    Kukacka, L.E.

    1992-01-01

    Advances in the development of new materials continue to be made in the geothermal materials project. Many successes have already been accrued and the results used commercially. In FY 1991, work was focused on reducing well drilling, fluid transport and energy conversion costs. Specific activities performed included lightweight CO{sub 2}-resistant well cements, thermally conductive and scale resistant protective liner systems, chemical systems for lost circulation control, corrosion mitigation in process components at The Geysers, and elastomer-metal bonding systems. Efforts to transfer the technologies developed in these efforts to other energy-related sectors of the economy continued and considerable success was achieved.

  13. Geothermal Energy.

    ERIC Educational Resources Information Center

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    An introduction to geothermal energy is provided in this discussion of: (1) how a geothermal reservoir works; (2) how to find geothermal energy; (3) where it is located; (4) electric power generation using geothermal energy; (5) use of geothermal energy as a direct source of heat; (6) geopressured reservoirs; (7) environmental effects; (8)…

  14. GTO-DOE\\/Industry Cost Shared Research; Microseismic Characterization and Monitoring in Geothermal Systems

    Microsoft Academic Search

    Majer

    1989-01-01

    The application of passive seismic studies in geothermal regions have undergone significant changes in the last 15 years. The primary application is now in the monitoring of subsurface processes, rather than exploration. A joint Geothermal Technology Organization (GTO) industry\\/DOE, monitoring project involving GEO, Unocal Geothermal, and LBL, was carried out at The Geysers geothermal field in northern California using a

  15. Energy balance and economic feasibility of shallow geothermal systems for winery industry

    NASA Astrophysics Data System (ADS)

    Ruiz-Mazarrón, F.; Almoguera-Millán, J.; García-Llaneza, J.; Perdigones, A.

    2012-04-01

    The search of energy efficient solutions has not yet been accomplished in agro-food constructions, for which technical studies and orientations are needed to find energy efficient solutions adapted to the environment. The main objective of this investigation is to evaluate the effectiveness of using shallow geothermal energy for the winery industry. World wine production in 2009 stood at 27100 millions of litres [1]. World spends 320 billion Euros on wine a year, according to industry insiders. On average, it is estimated that producing 1 litre of wine sold in a 75 cl glass bottle costs around 0.5-1.2 Euros /litre [2]. The process of ageing the wine could substantially increase production costs. Considering the time required for the aging of wine (months or years) and the size of the constructions, the use of an air conditioning system implies a considerable increase in energy consumption. Underground wine cellars have been in use for centuries for making and ageing wine. Ground thermal inertia provides protection from outdoor temperature oscillation and maintains thermal stability without energy consumption [3]. Since the last century, production of wine has moved to buildings above ground that have several advantages: lower construction cost, more space, etc. Nevertheless, these constructions require a large energy consumption to maintain suitable conditions for the ageing and conservation of wine. This change of construction techniques is the cause of an increase in energy consumption in modern wineries. The use of shallow geothermal energy can be a good alternative to take advantage of the benefits of aboveground buildings and underground constructions simultaneously. Shallow geothermal systems can meet the needs of heating and cooling using a single installation, maintaining low energy consumption. Therefore, it could be a good alternative to conventional HVAC systems. The main disadvantage of geothermal systems is the high cost of investment required. This paper analyzes the use of shallow geothermal systems in wineries, studying its feasibility versus conventional HVAC systems. A comparative analysis of six European locations will be performed. [1] OIV, Assessment on the world vitiviniculture situation in 2010, in, Organisation Internationale de la Vigne et du Vin, 2010. [2] FAO, Agribusiness Handbook: Grapes Wine, in, Investment Centre Division. FAO, 2009. [3] F.R. Mazarrón, J. Cid-Falceto, I. Cañas, An assessment of using ground thermal inertia as passive thermal technique in the wine industry around the world, Applied Thermal Engineering, 33-34 (0) (2012) 54-61.

  16. The Enhanced Geothermal System of Soultz-sous-Forêts: A study of the relationships between fracture zones and calcite content

    Microsoft Academic Search

    Ronan L. Hébert; Béatrice Ledésert; Danièle Bartier; Chrystel Dezayes; Albert Genter; Céline Grall

    2010-01-01

    The Enhanced Geothermal System (EGS) of Soultz-sous-Forêts (France) is made of three boreholes (GPK2, GPK3 and GPK4). The hydraulic connection between the wells, which is crucial to get an efficient geothermal exchanger, may be unfortunately hindered by the more or less complete sealing of fractures by hydrothermal neoformed minerals. This paper takes over the recent work of the authors that

  17. Multielement geochemistry of solid materials in geothermal systems and its applications. Part 1. Hot-water system at the Roosevelt Hot Springs KGRA, Utah

    SciTech Connect

    Bamford, R.W.; Christensen, O.D.; Capuano, R.M.

    1980-02-01

    Geochemical studies of the geothermal system at Roosevelt Hot Springs, Utah, have led to development of chemical criteria for recognition of major features of the system and to a three-dimensional model for chemical zoning in the system. Based on this improved level of understanding several new or modified geochemical exploration and assessment techniques have been defined and are probably broadly applicable to evaluation of hot-water geothermal systems. The main purpose of this work was the development or adaptation of solids geochemical exploration techniques for use in the geothermal environment. (MHR)

  18. TOUGH2 grid generator for simulations of geothermal heat pump systems

    NASA Astrophysics Data System (ADS)

    Kim, Seong-Kyun; Bae, Gwang-Ok; Lee, Kang-Kun

    2015-04-01

    We present a method to generate an unstructured Voronoi grid for its use in TOUGH2 simulations of geothermal heat pump systems. A series of codes is developed to create Voronoi cell center points that are placed at specific positions for well- or pipe-shaped Voronoi grids, to generate a three-dimensional grid and TOUGH2 input files from generated Voronoi cell vertices, and to visualize the generated grid and simulation results by ParaView. AMESH program is used to calculate the x- and y-coordinates of the Voronoi cell vertices from the Voronoi cell center points. We show the desired form of grid from the developed series of codes and test with confidence the presented method through simulations of water production/injection from/to the various kinds of the geothermal wells.

  19. Microseismic Activity in Low-Hazard Geothermal Settings in Southern Germany

    Microsoft Academic Search

    T. Megies; J. M. Wassermann

    2010-01-01

    In the last few years several geothermal power plants have taken up production in southern Germany and many more are currently in exploration or construction stages. One of the most promising areas in Germany with respect to geothermal exploitation is the Bavarian Molasse Basin: A karstified limestone formation at a few kilometers depth provides sufficiently high temperatures also for power

  20. Insights From Laboratory Experiments On Simulated Faults With Application To Fracture Evolution In Geothermal Systems

    SciTech Connect

    Stephen L. Karner, Ph.D

    2006-06-01

    Laboratory experiments provide a wealth of information related to mechanics of fracture initiation, fracture propagation processes, factors influencing fault strength, and spatio-temporal evolution of fracture properties. Much of the existing literature reports on laboratory studies involving a coupling of thermal, hydraulic, mechanical, and/or chemical processes. As these processes operate within subsurface environments exploited for their energy resource, laboratory results provide insights into factors influencing the mechanical and hydraulic properties of geothermal systems. I report on laboratory observations of strength and fluid transport properties during deformation of simulated faults. The results show systematic trends that vary with stress state, deformation rate, thermal conditions, fluid content, and rock composition. When related to geophysical and geologic measurements obtained from engineered geothermal systems (e.g. microseismicity, wellbore studies, tracer analysis), laboratory results provide a means by which the evolving thermal reservoir can be interpreted in terms of physico-chemical processes. For example, estimates of energy release and microearthquake locations from seismic moment tensor analysis can be related to strength variations observed from friction experiments. Such correlations between laboratory and field data allow for better interpretations about the evolving mechanical and fluid transport properties in the geothermal reservoir – ultimately leading to improvements in managing the resource.

  1. Geothermal Progress Monitor 12

    SciTech Connect

    None

    1990-12-01

    Some of the more interesting articles in this GPM are: DOE supporting research on problems at The Geysers; Long-term flow test of Hot Dry Rock system (at Fenton Hill, NM) to begin in Fiscal Year 1992; Significant milestones reached in prediction of behavior of injected fluids; Geopressured power generation experiment yields good results. A number of industry-oriented events and successes are reported, and in that regard it is noteworthy that this report comes near the end of the most active decade of geothermal power development in the U.S. There is a table of all operating U.S. geothermal power projects. The bibliography of research reports at the end of this GPM is useful. (DJE 2005)

  2. Geothermal materials development

    SciTech Connect

    Kukacka, L.E.

    1991-02-01

    Advances in the development of new materials, the commercial availabilities of which are essential for the attainment of Hydrothermal Category Level 1 and 2 Objectives, continue to be made in the Geothermal Materials Development Project. Many successes have already been accrued and the results transferred to industry. In FY 1990, the R D efforts were focused on reducing well drilling and completion costs and on mitigating corrosion in well casing. Activities on lost circulation control materials, CO{sub 2}- resistant lightweight cements, and thermally conductive corrosion and scale-resistant protective liner systems have reached the final development stages, and cost-shared field tests are planned for the FY 1991--1992 time frame. Technology transfer efforts on high temperature elastomers for use in drilling tools are continuing under Geothermal Drilling Organization (GDO) sponsorship.

  3. The evolution of volcano-hosted geothermal systems based on deep wells from Karaha-Telaga Bodas, Indonesia

    USGS Publications Warehouse

    Moore, J.N.; Allis, R.G.; Nemcok, M.; Powell, T.S.; Bruton, C.J.; Wannamaker, P.E.; Raharjo, I.B.; Norman, D.I.

    2008-01-01

    Temperature and pressure surveys, fluid samples, and petrologic analyses of rock samples from deep drill holes at the Karaha - Telaga Bodas geothermal field on the volcanic ridge extending northward from Galunggung Volcano, West Java, have provided a unique opportunity to characterize the evolution of an active volcano-hosted geothermal system. Wells up to 3 km in depth have encountered temperatures as high as 353??C and a weakly altered granodiorite that intruded to within 2 to 3 km of the surface. The intrusion is shallowest beneath the southern end of the field where an acid lake overlies a nearly vertical low resistivity structure (<10 ohm-m) defined by magnetotelluric measurements. This structure is interpreted to represent a vapor-dominated chimney that provides a pathway to the surface for magmatic gases. Four distinct hydrothermal mineral assemblages document the evolution of the geothermal system and the transition from liquid- to vapor-dominated conditions. The earliest assemblage represents the initial liquid-dominated system generated during emplacement of the granodiorite between 5910 ?? 76 and 4200 ?? 150 y BP. Tourmaline, biotite, actinolite, epidote and clay minerals were deposited contemporaneously at progressively greater distances from the intrusive contact (assemblage 1). At 4200 ?? 150 y BP, flank collapse and the formation of the volcano's crater, Kawah Galunggung, resulted in catastrophic decompression and boiling of the hydrothermal fluids. This event initiated development of the modern vapor-dominated regime. Chalcedony and then quartz were deposited as the early low salinity liquids boiled (assemblage 2). Both vapor- and liquid-rich fluid inclusions were trapped in the quartz crystals. Liquid-rich fluid inclusions from the southern part of the field record salinities ranging from 0 to 26 weight percent NaCl- CaCl2 equivalent and locally contain fluorite daughter crystals. We suggest, based on temperature-salinity relationships and evidence of boiling, that these fluids were progressively concentrated as steam was lost from the system. However, mixing with fluids derived from the underlying intrusion or generated during the formation of acid SO4 water on the vapor-dominated chimney margins could have contributed to the observed salinities. As pressures declined, CO2- and SO4-rich steam-heated water drained downward, depositing anhydrite and calcite (assemblage 3) in the fractures, limiting further recharge. Fluid inclusions with salinities up to 31 weight percent NaCl equivalent were trapped in these minerals as the descending water vaporized. The final assemblage is represented by precipitates of NaCl, KCl and FeClx deposited on rock surfaces in portions of the vapor-dominated zone that boiled dry. Vapor-dominated conditions extend over a distance of at least 10 km and to depths below sea level. Deep wells drilled into the underlying liquid-dominated reservoir in the northern and central part of the volcanic ridge produce low salinity fluids representing recent recharge of meteoric and steam-heated water. The evolution of volcanic-hosted vapor-dominated geothermal systems can be described by a five stage model. Stage 1 involves the formation of an over-pressured liquid-dominated geothermal system soon after magmatic intrusion. In Stages 2 and 3, pressures progressively decrease, and a curtain of steam-heated water surrounding a magmatic vapor-dominated chimney at 350??C and 14 ?? 2 MPa develops. The relatively low pressure near the base of the chimney causes liquid inflow adjacent to the intrusion and the development of a secondary marginal vapor-dominated zone. In Stage 4, the magmatic vapor discharge from the intrusion becomes small, vapor pressure declines, and the secondary vapor-dominated zone expands above the intrusion. In Stage 5, the vapor-dominated zone floods because heat from the intrusion is insufficient to boil all liquid inflow. A more common, liquid-dominated volcanic-hosted system the

  4. An Assessment of the Tectonic Control in Defining the Geothermal System(s) of the Southern Chilean Andes

    NASA Astrophysics Data System (ADS)

    Sánchez, P.; Alam, M.; Parada, M.; Lahsen, A.

    2010-12-01

    Geothermal manifestations between Villarrica and Chihuio (39°15'-40°15'S, 71°40'-72°10'W), in the southern Chilean Andes, have been studied to assess the tectonic control in defining the geothermal systems of the area. These surface manifestations are in close spatial relationship with either the stratovolcanoes or the Liquiñe-Ofqui Fault Zone (LOFZ, Cembrano et al., 1996). Volcanism and regional tectonics control the two vital components of the geothermal systems, viz., heat source and permeability. Two distinct domains of the geothermal systems, viz., structural (or non-volcanic) and volcanic have been identified, based on the chemical signatures of the thermal discharges and structural analysis of the lineaments. These two domains are distinct in their ways of heating up of meteoric water. The geothermal system(s) of the volcanic domain are closely associated with the volcanic centers, spatially as well as geochemically. In the case of the geothermal system(s) of volcanic domain, the heating of meteoric water is through absorption of heat and condensation of steam and gases by meteoric water during lateral circulation. These discharges do not exhibit the typical signatures of steam heated waters, which are subdued by near surface processes. The relation between the geothermal systems and fault and fracture density (FFD) is quite evident from the lineaments analysis. FFD correlates very well with the surface geothermal manifestations, as well as with their recharge areas. An increase in the (secondary) permeability in the uppermost 200-300 m in the areas of relatively high FFD values, necessary for lateral flow, is consistent with the lithology, structure and stratigraphy of the area. Although the lineaments scatter in a wide range, the absence of lineaments between N60°E and N100°E is noticeable, and is consistent with displacement and stress data of LOFZ (Lavenu and Cembrano, 1999; Cembrano et al., 2007; Lara and Cembrano, 2009). This indicates that such lineaments, which represent fractures and faults, are the result of recent deformation, causing secondary permeability that facilitates the subsurface flow particularly in NW-SE and N-S directions. Differential rates of exhumation and frictional heating (Parada et al., 2000; Thomson, 2002; Adriasola et al., 2006; Glodny et al., 2008) are the other two controlling factors for the geothermal systems of the area. (Project Funding: PBCT-PDA07) References: Adriasola, A.C., Thomson, S.N., Brix, M.R., Hervé, F., Stóckhert, B., 2006. Int. J. Earth Sci. 95: 501-528. Cembrano, J., Hervé, F., Lavenu, A., 1996. Tectonophysics 259: 55-66. Cembrano, J., Lara, L., 2009. Tectonophysics 471: 96-113. Cembrano, J., Lavenu, A., Yañez, G. (coordinators), Riquelme, R., Garcia, M., González, G., Herail, G., 2007. In: T. Moreno, W. Gibbons (Eds), The Geology of Chile, The Geological Society, London, 147-178. Cembrano, J., Schermer, E., Lavenu, A., Sanhueza, A., 2000. Tectonophysics 319: 129-149. Glodny, J., Gräfe, K., Echtler, H., Rosenau, M., 2008. Int. J. Earth Sci. 97: 1271-1291 Lavenu, A., Cembrano, J., 1999. J. Struct. Geol. 21: 1669-1691. Parada, M.A., Lahsen, A., Palacios, C., 2000. Geological Society of America Special Papers 2000, 91: 169- 179. Thomson, S.N., 2002. Geol. Soc. Am. Bull. 114: 1159-1173.

  5. Carbon-dioxide plume geothermal (CPG) systems, an alternative engineered geothermal system (EGS) that does not require hydrofracturing: Comparison with traditional EGS regarding geologic reservoir heat energy extraction and potential for inducing seismicity

    NASA Astrophysics Data System (ADS)

    Randolph, J. B.; Saar, M. O.

    2010-12-01

    Traditional enhanced or engineered geothermal systems (EGS) typically require hydrofracturing of rock with low natural permeability, which may induce seismicity, leading to significant socio-political resistance. In contrast, the approach described here does not rely on hydrofracturing or similar permeability-enhancing technologies but, rather, utilizes existing high-permeability and high-porosity geologic reservoirs that are overlain by a low-permeability caprock. Carbon dioxide (CO2) is pumped into such reservoirs, where it forms a CO2 plume that largely displaces native formation fluid and is heated by the natural in-situ heat and background geothermal heat flux. A portion of the heated CO2 is piped to the surface to power generators and/or to provide heat for direct use before being returned to the subsurface. Non-recoverable CO2 in the subsurface is geologically sequestered, serving as a CO2 sink that mitigates anthropogenic greenhouse gas emissions to the atmosphere. Furthermore, the amount of CO2 sequestered in such a CO2-plume geothermal (CPG) system is much larger than in more traditional fracture-dominated CO2-based EGS approaches. Here, we compare the geothermal heat energy extraction potential between CPG and traditional water- or CO2-based EGS approaches. Thereafter, we contrast the risk of induced seismicity associated with hydrofracturing in traditional EGS versus that of technologies that require only the fluid injection and production component of geothermal system operations, such as CPG, but minimal-to-no reservoir stimulation. While additional research is required, numerical simulation results at present suggest CPG systems would be viable geothermal energy sources for electric power production for decades, potentially even in regions with low geothermal temperatures and heat flow rates. In addition, CPG systems are expected to significantly reduce the risk of inducing seismicity compared to traditional EGS.

  6. Geochemical processes in an active shallow submarine hydrothermal system, Bahía Concepción, México: mixing or boiling?

    Microsoft Academic Search

    Ruth Esther Villanueva-Estrada; Rosa María Prol-Ledesma; Augusto Antonio Rodríguez-Díaz; Carles Canet; Ignacio S. Torres-Alvarado; Eduardo González-Partida

    2011-01-01

    Hydrothermal activity at Bahía Concepción, on the western coast of the Gulf of California, is not linked to present volcanic activity. This site is a potential energy source; however, geothermal modelling of the system is needed in order to determine the processes that generated this activity. Two processes might lead to the formation of the secondary fluids that were sampled

  7. Geochemical processes in an active shallow submarine hydrothermal system, Bahía Concepción, México: mixing or boiling?

    Microsoft Academic Search

    Ruth Esther Villanueva-Estrada; Rosa María Prol-Ledesma; Augusto Antonio Rodríguez-Díaz; Carles Canet; Ignacio S. Torres-Alvarado; Eduardo González-Partida

    2012-01-01

    Hydrothermal activity at Bahía Concepción, on the western coast of the Gulf of California, is not linked to present volcanic activity. This site is a potential energy source; however, geothermal modelling of the system is needed in order to determine the processes that generated this activity. Two processes might lead to the formation of the secondary fluids that were sampled

  8. The Design of Large Geothermally Powered Air-Conditioning Systems Using an Optimal Control Approach

    NASA Astrophysics Data System (ADS)

    Horowitz, F. G.; O'Bryan, L.

    2010-12-01

    The direct use of geothermal energy from Hot Sedimentary Aquifer (HSA) systems for large scale air-conditioning projects involves many tradeoffs. Aspects contributing towards making design decisions for such systems include: the inadequately known permeability and thermal distributions underground; the combinatorial complexity of selecting pumping and chiller systems to match the underground conditions to the air-conditioning requirements; the future price variations of the electricity market; any uncertainties in future Carbon pricing; and the applicable discount rate for evaluating the financial worth of the project. Expanding upon the previous work of Horowitz and Hornby (2007), we take an optimal control approach to the design of such systems. By building a model of the HSA system, the drilling process, the pumping process, and the chilling operations, along with a specified objective function, we can write a Hamiltonian for the system. Using the standard techniques of optimal control, we use gradients of the Hamiltonian to find the optimal design for any given set of permeabilities, thermal distributions, and the other engineering and financial parameters. By using this approach, optimal system designs could potentially evolve in response to the actual conditions encountered during drilling. Because the granularity of some current models is so coarse, we will be able to compare our optimal control approach to an exhaustive search of parameter space. We will present examples from the conditions appropriate for the Perth Basin of Western Australia, where the WA Geothermal Centre of Excellence is involved with two large air-conditioning projects using geothermal water from deep aquifers at 75 to 95 degrees C.

  9. Geologic and hydrologic research on the Moana geothermal system, Washoe County, Nevada

    SciTech Connect

    Flynn, T.; Ghusn, G. Jr.

    1983-12-01

    The Moana geothermal area is the largest single low- to moderate-temperature geothermal resource in the State of Nevada presently employed for direct-use applications. Approximately 150 individual wells, representing a total estimated investment of $5 to $7 million, are presently used to provide heat ahd hot water to more than 130 private residences, several churches and two large motels. Although most of the wells are constructed to meet the heating needs of individual homes, a large-scale district space heating system, designed to supply heat to 60 houses from a single well, is now being developed. Usable temperatures range from 50 to 99/sup 0/C (120 to 210/sup 0/F); well depths range from 60 to 400 m (100 to 1300 ft). The number of new wells coming on-line in Moana is two to three per month. Development of the resource has been largely unregulated and questions dealing with reported reservoir temperature and water level declines, loss of artesian flow, and fluid disposal have recently surfaced. In October 1982, a geologic and hydrologic research program began that was designed to provide detailed geothermal reservoir data to present or prospective developers. The program combines geophysical, geochemical, and geological surveys of the Moana resource area with a drilling program for 5 monitor/observation wells. Data from this program are supplied directly to developers as well as state and local government agencies to provide for prudent resource development. This paper summarizes the program elements and describes the present status.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Geothermal direct-heat utilization assistance: Federal assistance program. Quarterly project progress report, October--December 1995

    SciTech Connect

    NONE

    1996-02-01

    The report summarizes geothermal technical assistance, R&D and technology transfer activities of the Geo-Heat Center at Oregon Institute of Technology for the first quarter of FY-96. It describes 90 contacts with parties during this period related to technical assistance with geothermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, equipment and resources. Research activities are summarized on low-temperature resource assessment, geothermal district heating system cost evaluation and silica waste utilization project. Outreach activities include the publication of a geothermal direct use Bulletin, dissemination of information, geothermal library, technical papers and seminars, development of a webpage, and progress monitor reports on geothermal resources and utilization.

  12. Geothermal drilling technology update

    SciTech Connect

    Glowka, D.A.

    1997-04-01

    Sandia National Laboratories conducts a comprehensive geothermal drilling research program for the US Department of Energy, Office of Geothermal Technologies. The program currently includes seven areas: lost circulation technology, hard-rock drill bit technology, high-temperature instrumentation, wireless data telemetry, slimhole drilling technology, Geothermal Drilling Organization (GDO) projects, and drilling systems studies. This paper describes the current status of the projects under way in each of these program areas.

  13. Application of seismic tomographic techniques in the investigation of geothermal systems

    SciTech Connect

    Romero, A.E. Jr.

    1995-05-01

    The utility of microearthquake data for characterizing the Northwest Geysers geothermal field and the Long Valley Caldera (LVC) was investigated. Three-dimensional (3-D) P- and S-wave seismic velocity models were estimated for the Coldwater Creek Steam Field (CCSF) in the Northwest Geysers region. Hypocenters relocated using these 3-D models appear to be associated with the steam producing zone, with a deeper cluster of hypocenters beneath an active injection well. Spatial and temporal patterns of seismicity exhibit strong correlation with geothermal exploitation. A 3-D differential attenuation model was also developed for the CCSF from spectral ratios corrected for strong site effects. High-velocity anomalies and low attenuation in the near surface correspond to Franciscan metagraywacke and greenstone units. Microearthquakes recorded at seismographic stations located near the metagraywacke unit exhibit high corner frequencies. Low-velocity anomalies and higher attenuation in the near surface are associated with sections of Franciscan melange. Near-surface high attenuation and high Vp/Vs are interpreted to indicate liquid-saturated regions affected by meteoric recharge. High attenuation and low Vp/Vs marks the steam producing zone, suggesting undersaturation of the reservoir rocks. The extent of the high attenuation and low Vp/Vs anomalies suggest that the CCSF steam reservoir may extend northwestward beyond the known producing zone. This study concludes that microearthquake monitoring may be useful as an active reservoir management tool. Seismic velocity and attenuation structures as well as the distribution of microearthquake activity can be used to identify and delineate the geothermal reservoir, while temporal variations in these quantities would be useful in tracking changes during exploitation.

  14. Technical support for geopressured-geothermal well activities in Louisiana; Final report, 1 January 1992--31 December 1993

    Microsoft Academic Search

    1994-01-01

    The US Department of Energy has operated continuous-recording, microearthquake monitoring networks at geopressured-geothermal test well sites since 1980. These microseismic networks were designed to detect microearthquakes indicative of fault activation and\\/or subsidence that can potentially result from the deep subsurface withdrawal and underground disposal of large volumes of brine during well testing. Seismic networks were established before the beginning of

  15. Identification of High Angle Structures Controlling the Geothermal System at Rye Patch, Nevada.

    NASA Astrophysics Data System (ADS)

    Ehni, W. J.

    2001-12-01

    The successful completion of a recent well in the Rye Patch Geothermal field, located in Pershing County, Nevada, supports the geologic and geophysical interpretation that high angle structures control this geothermal system. Although lower angle structures are present, hot water migrates up from deeper sources along high angle faults more efficiently than structures with a shallower dip. Earlier attempts to develop the resource focused on structures that dipped at an angle between 60 and 70 degrees from horizontal. Recently acquired geophysical data indicated that numerous high angle structures were present in the area, with dips between 80 and 90 degrees. Original drilling targets focused on the subsurface projection of a surface structure, mapped as the Rye Patch fault, with an erroneously low angle. These early attempts at drilling were discouraging and might have been more successful if additional geology and geophysics were used to evaluate the geothermal system and map the Rye Patch fault more accurately. The successful completion of the most recent well can be attributed to the incorporation of the geology of previous wells with additional geology and geophysics. Temperature gradient holes were used to confirm that the Rye Patch fault provided the primary plumbing for this geothermal system, and 3D seismic data indicated that most of the structures had dips between 80 and 90 degrees. Geothermometry at Rye Patch indicates that the resource has a relatively high quartz equilibrium temperature and it is speculated that the higher the angle of the structural control, the higher the resource temperature. The dip of Basin and Range normal faults varies considerably and the interpretation of these structures for geothermal, fossil geothermal mineral prospects, and or oil and gas prospects is important. At Rye Patch, the high angle structure feeds geothermal fluids into cavernous limestone beds, dipping to the west usually between 40 and 60 degrees, which is a shallower dip than the Rye Patch fault itself. Resistivity surveys at Rye Patch mapped the westward dipping anomalies, which correspond to the cavernous limestone porosity, and numerous vertical anomalies; which are attributable to the high angle normal faults. Time slices of interpreted 3D seismic data identified numerous high angle structures; however none of these seismic structures could be correlated with the Rye Patch fault. It is inferred that the Rye Patch Fault is the youngest fault in the system, having the only surface expression, and therefore the least amount of displacement, resulting in a difficult seismic target. The most recent well was targeted to intercept the Rye Patch fault at 4500' after evaluating the shallower intermediate depth limestone reservoir at about 2000'. Upon testing of the intermediate depth reservoir it was concluded that this zone was capable of commercial production and the well would be completed in this shallower interval

  16. Geothermal Water Use: Life Cycle Water Consumption, Water Resource Assessment, and Water Policy Framework

    SciTech Connect

    Schroeder, Jenna N.

    2014-06-10

    This report examines life cycle water consumption for various geothermal technologies to better understand factors that affect water consumption across the life cycle (e.g., power plant cooling, belowground fluid losses) and to assess the potential water challenges that future geothermal power generation projects may face. Previous reports in this series quantified the life cycle freshwater requirements of geothermal power-generating systems, explored operational and environmental concerns related to the geochemical composition of geothermal fluids, and assessed future water demand by geothermal power plants according to growth projections for the industry. This report seeks to extend those analyses by including EGS flash, both as part of the life cycle analysis and water resource assessment. A regional water resource assessment based upon the life cycle results is also presented. Finally, the legal framework of water with respect to geothermal resources in the states with active geothermal development is also analyzed.

  17. Geothermal Water Use: Life Cycle Water Consumption, Water Resource Assessment, and Water Policy Framework

    DOE Data Explorer

    Schroeder, Jenna N.

    This report examines life cycle water consumption for various geothermal technologies to better understand factors that affect water consumption across the life cycle (e.g., power plant cooling, belowground fluid losses) and to assess the potential water challenges that future geothermal power generation projects may face. Previous reports in this series quantified the life cycle freshwater requirements of geothermal power-generating systems, explored operational and environmental concerns related to the geochemical composition of geothermal fluids, and assessed future water demand by geothermal power plants according to growth projections for the industry. This report seeks to extend those analyses by including EGS flash, both as part of the life cycle analysis and water resource assessment. A regional water resource assessment based upon the life cycle results is also presented. Finally, the legal framework of water with respect to geothermal resources in the states with active geothermal development is also analyzed.

  18. Numerical modeling of the impact of temperature on the behavior of minerals in the Soultz-sous-Forêts enhanced geothermal system

    NASA Astrophysics Data System (ADS)

    Van Ngo, Viet; Lucas, Yann; Clément, Alain; Fritz, Bertrand

    2015-04-01

    Operation of the enhanced geothermal system (EGS) requires to re-inject fluid, after heat exchange at the surface to the energy production, into the geothermal reservoir. This cold re-injected fluid can cause a strong disequilibrium with the fluid and granitic rock within the geothermal reservoir and then implies the possible dissolution/precipitation of minerals. The hydrothermal alterations include the transformation of plagioclase, biotite and K-feldspar and the precipitation of various secondary minerals. The major sealing phases observed in the main fracture zones are quartz, calcite, and clay minerals. These mineralogical transformations may modify the porosity, permeability and fluid pathways of the geothermal reservoir. In the Soultz-sous-Forêts EGS (Alsace, France), the hydraulic connection between the injection well and the production well is quite poor. Therefore, understanding the impact of changes in temperature, which are caused by the re-injected fluid, on the behavior of minerals (especially for the main newly-formed minerals such as quartz, calcite and clay minerals) is a critical preliminary step for the long-term prediction of their evolution. The approach used in the present work is typically based on a geochemical code, called THERMA, which enables to calculate the changes in equilibrium constants of all primary and secondary minerals and aqueous species as a function of temperature. Our model accounted for a wide range of different mineral groups in order to make sure a large freedom for the numerical calculations. The modeling results showed that when the temperature of geothermal reservoir is cooled down, quartz, calcite, illites, galena and pyrite have tendency towards equilibrium state, which indicates that they are precipitated under the geothermal conditions. In contrast, other minerals including plagioclase, K-feldspar and biotite remained unsaturated. These behaviors of minerals were further illustrated by the Khorzinsky stability diagrams, which are based on the activities of different species such as H4SiO4, Ca2+, Mg2+, and Al3+ and take into account partial CO2 pressure,. The modeling results further suggested that we should pay a special attention to the main minerals (e.g., quartz, calcite and illites) when studying the changes in porosity and permeability of the geothermal reservoir. This study was preparing a simulation of water-rock interaction processes related to these temperature conditions.

  19. Summary of geothermal exploration activity in the state of Washington from 1978 to 1983

    SciTech Connect

    Korosec, M.A.

    1984-01-01

    During the course of conducting the statewide reconnaissance study of Washington's potential geothermal resources, several specific areas and broader regions have been identified as targets which warrant a more concentrated effort. Over the past three years, the program has continued to identify new sites, but has concentrated on better defining the resource potential of the best areas. The locations of these geothermal areas are shown, and the level of progress for each area is shown, expressed as a percentage of completion for the various exploration tasks. Descriptions of the geothermal target areas are presented.

  20. 1993 status report - The Bonneville Power Administration's geothermal program

    SciTech Connect

    Darr, G.D. (Bonneville Power Administration, Portland, OR (United States))

    1993-01-01

    The Bonneville Power Administration's (BPA) Geothermal Program includes up to three demonstration (pilot) power projects that will initiate development of high-potential reservoirs in the Pacific Northwest. The program also includes activities that support the pilot projects and that encourage the use of the region's geothermal resources. Activities supporting the pilot projects include initiating environmental baseline monitoring programs and conducting environmental and economic impact studies. Research activities include efforts to better understand the cold water blanket phenomenon in the Cascades, a study to characterize the hydrothermal system in the Pueblo Valley, a geothermal exploration program in southeastern Oregon, and support for research to expand the use of slim-holes for resource confirmation. Efforts to address institutional issues include support for the Regional Renewables Project, which will help Northwest environmentalists become more knowledgeable about the role of conservation and renewables in the region's energy picture. A guide to geothermal permitting and licensing was prepared to help developers and utilities find their way through the regulatory maze. A geothermal curriculum is being developed for grades 4 through 8 in the Oregon schools. Data on the location and operating experience of existing U.S. geothermal plants has been collected in a database. Market penetration of geothermal heat pumps is being encouraged through a demonstration project in Montana and by helping BPA customers prepare proposals for geothermal heat pump projects that can compete successfully in BPA power acquisitions.

  1. Naturally occurring arsenic in terrestrial geothermal systems of western Anatolia, Turkey: potential role in contamination of freshwater resources.

    PubMed

    Bundschuh, Jochen; Maity, Jyoti Prakash; Nath, Bibhash; Baba, Alper; Gunduz, Orhan; Kulp, Thomas R; Jean, Jiin-Shuh; Kar, Sandeep; Yang, Huai-Jen; Tseng, Yu-Jung; Bhattacharya, Prosun; Chen, Chien-Yen

    2013-11-15

    Arsenic (As) contamination in terrestrial geothermal systems has been identified in many countries worldwide. Concentrations higher than 0.01 mg/L are detrimental to human health. We examined potential consequences for As contamination of freshwater resources based on hydrogeochemical investigations of geothermal waters in deep wells and hot springs collected from western Anatolia, Turkey. We analyzed samples for major ions and trace element concentrations. Temperature of geothermal waters in deep wells showed extreme ranges (40 and 230 °C), while, temperature of hot spring fluids was up to 90 °C. The Piper plot illustrated two dominant water types: Na-HCO3(-) type for geothermal waters in deep wells and Ca-HCO3(-) type for hot spring fluids. Arsenic concentration ranged from 0.03 to 1.5mg/L. Dominance of reduced As species, i.e., As(III), was observed in our samples. The Eh value ranged between -250 and 119 mV, which suggests diverse geochemical conditions. Some of the measured trace elements were found above the World Health Organization guidelines and Turkish national safe drinking water limits. The variation in pH (range: 6.4-9.3) and As in geothermal waters suggest mixing with groundwater. Mixing of geothermal waters is primarily responsible for contamination of freshwater resources and making them unsuitable for drinking or irrigation. PMID:23498168

  2. Geothermal direct-heat utilization assistance. Quarterly report, January - March 1997

    SciTech Connect

    Lienau, P.

    1997-04-01

    This report summarizes geothermal technical assistance, R&D and technology transfer activities of the Geo-Heat Center at Oregon Institute of Technology for the second quarter of FY-97. It describes 176 contacts with parties during this period related to technical assistance with geothermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, equipment, economics and resources. Research activities are summarized on well pumping in commercial groundwater heat pump systems. A memorandum of understanding between the GHC and EIA is described. Work accomplishments on the Guidebook are discussed. Outreach activities include the publication of a geothermal direct use Bulletin, dissemination of information, geothermal library, technical papers and seminars, and progress monitor reports on geothermal resources and utilization.

  3. Geothermal direct-heat utilization assistance

    NASA Astrophysics Data System (ADS)

    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.

  4. Noble-gas evidence for geothermal activity in a karstic terrain: Rocky Mountains, Canada.

    NASA Astrophysics Data System (ADS)

    Mazor, Emanuel; van Everdingen, Robert O.; Krouse, H. Roy

    1983-06-01

    Geothermally heated fluids are identified as a component in warm (up to 54°C) springs in the southern Canadian Rocky Mountains. High concentrations of radiogenic He (10 -3 ccSTP/cc gas) and atmospheric Ne, Ar, Kr and Xe in the gases that vigorously bubble at the Fairmont Hot Spring, assign the latter to be a "drowned" fumarole, fed by geothermal steam. Up to 75% depletions in the atmospheric noble gases in several warm springs indicate contributions of residual geothermal water. On the other hand, in a few cases noble gases were found in excess ( W) over the expected concentrations in airequilibrated recharge water. The observed "reversed" pattern of wnc > WAr > Wkr > Wxe is interpreted as excess air, incorporated during recharge through karstic conduits. The mixing ratios of geothermal and karstic waters can be deduced.

  5. THERMAL CHARACTERISTICS OF THE CHENA HOT SPRINGS ALASKA GEOTHERMAL SYSTEM

    Microsoft Academic Search

    Kamil Erkan; Gwen Holdman; David Blackwell; Walter Benoit

    Chena Hot Springs is located in the east-central part of the Alaska within the Yukon-Tanana Plateau, about 75 km east of Fairbanks. It is a moderate temperature deep circulation system typical of interior Alaska. The main shallow upflow zone is about 2000 ft long and 300 ft wide. The system is located at the edge of a granitic body where

  6. Active optical zoom system

    DOEpatents

    Wick, David V.

    2005-12-20

    An active optical zoom system changes the magnification (or effective focal length) of an optical imaging system by utilizing two or more active optics in a conventional optical system. The system can create relatively large changes in system magnification with very small changes in the focal lengths of individual active elements by leveraging the optical power of the conventional optical elements (e.g., passive lenses and mirrors) surrounding the active optics. The active optics serve primarily as variable focal-length lenses or mirrors, although adding other aberrations enables increased utility. The active optics can either be LC SLMs, used in a transmissive optical zoom system, or DMs, used in a reflective optical zoom system. By appropriately designing the optical system, the variable focal-length lenses or mirrors can provide the flexibility necessary to change the overall system focal length (i.e., effective focal length), and therefore magnification, that is normally accomplished with mechanical motion in conventional zoom lenses. The active optics can provide additional flexibility by allowing magnification to occur anywhere within the FOV of the system, not just on-axis as in a conventional system.

  7. OPTIMIZATION OF HYBRID GEOTHERMAL HEAT PUMP SYSTEMS Scott Hackel, Graduate Research Assistant; Gregory Nellis, Professor; Sanford Klein,

    E-print Network

    Wisconsin at Madison, University of

    1 OPTIMIZATION OF HYBRID GEOTHERMAL HEAT PUMP SYSTEMS Scott Hackel, Graduate Research Assistant, Madison, WI, United States Abstract: Hybrid ground-coupled heat pump systems (HyGCHPs) couple conventional ground- coupled heat pump (GCHP) equipment with supplemental heat rejection or extraction systems

  8. Metal fluxing in a large-scale intra-arc fault: insights from the Liquiñe-Ofqui Fault System (LOFS) and associated geothermal fields in southern Chile

    NASA Astrophysics Data System (ADS)

    Tardani, D.; Reich, M.; Sano, Y.; Takahata, N.; Wen, H.; Roulleau, E.; Sanchez-Alfaro, P.; González-Jiménez, J. M.; Shinohara, H.; Yang, T. F.; Cembrano, J. M.; Arancibia, G.

    2014-12-01

    In compressional and extensional settings, high-enthalpy geothermal systems and epithermal vein deposits are genetically linked to shallow magmatic reservoirs, overlying hydrothermal circulation cells, and structural meshes that permit vertical migration of fluids. In the Andean Cordillera of Central-Southern Chile, the nature of the relationship between tectonics and volcanism is the result of interaction between the crustal structures and the regional stress field. Between 37° and 46°S, the volcanic and geothermal activity is controlled by the NNE-trending, 1,200 km long LOFS, an intra-arc dextral strike-slip fault system, associated with second-order intra-arc anisotropies of overall NE-SW and NW-SE orientation. Although there is consensus that volcanism in this segment are controlled by the regional scale tectonic stress field, the structural controls on magma degassing and metal fluxing remains poorly constrained. The goal of the study is to constrain the first-order controls on fluxes of noble metals (Au, Ag, PGEs), base metals (Cu, Zn, Pb) and metalloids (As, Sb, Se) along this segment. For this purpose we collected fumarole and thermal water samples from five selected volcanic-geothermal systems along the northern termination of the LOFS. The selected areas are characterized by the occurrence of surface manifestations and are located along NNE-oriented or NWN-oriented fault systems. In each location, the trace metal budget and isotopic composition of fumaroles and springs were constrained along with cations, anions and dissolved gaseous species. The helium isotopic ratios of fumaroles, defined as R/Ra, range between 3.5 and 7.5 in the studied segment. High R/Ra, mantle-like signatures are associated with geothermal manifestations occurring along NNE-trending faults, whereas lower R/Ra values in NWN-oriented systems most likely represent mixing between mantle and crustal sources. Concentrations of Au, Cu and As are significant in selected geothermal wells along NWN-faults (1.5 ppb, 8 ppb and 25 ppm, respectively), while measured concentrations of PGEs in fumaroles are detectable (between 0.6 and 14 ppt of Pt, Pd, Rh and Ir) along both NWE and NNE-trending structures. This study point out towards provide new insights about large-scale metal fluxing along an active intra-arc fault system.

  9. Geothermal Program Review XI: proceedings. Geothermal Energy - The Environmental Responsible Energy Technology for the Nineties

    SciTech Connect

    Not Available

    1993-10-01

    These proceedings contain papers pertaining to current research and development of geothermal energy in the USA. The seven sections of the document are: Overview, The Geysers, Exploration and Reservoir Characterization, Drilling, Energy Conversion, Advanced Systems, and Potpourri. The Overview presents current DOE energy policy and industry perspectives. Reservoir studies, injection, and seismic monitoring are reported for the geysers geothermal field. Aspects of geology, geochemistry and models of geothermal exploration are described. The Drilling section contains information on lost circulation, memory logging tools, and slim-hole drilling. Topics considered in energy conversion are efforts at NREL, condensation on turbines and geothermal materials. Advanced Systems include hot dry rock studies and Fenton Hill flow testing. The Potpourri section concludes the proceedings with reports on low-temperature resources, market analysis, brines, waste treatment biotechnology, and Bonneville Power Administration activities. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  10. Structural Inventory of Great Basin Geothermal Systems and Definition of Favorable Structural Settings

    SciTech Connect

    Faulds, James E.

    2013-12-31

    Over the course of the entire project, field visits were made to 117 geothermal systems in the Great Basin region. Major field excursions, incorporating visits to large groups of systems, were conducted in western Nevada, central Nevada, northwestern Nevada, northeastern Nevada, east?central Nevada, eastern California, southern Oregon, and western Utah. For example, field excursions to the following areas included visits of multiple geothermal systems: - Northwestern Nevada: Baltazor Hot Spring, Blue Mountain, Bog Hot Spring, Dyke Hot Springs, Howard Hot Spring, MacFarlane Hot Spring, McGee Mountain, and Pinto Hot Springs in northwest Nevada. - North?central to northeastern Nevada: Beowawe, Crescent Valley (Hot Springs Point), Dann Ranch (Hand?me?Down Hot Springs), Golconda, and Pumpernickel Valley (Tipton Hot Springs) in north?central to northeast Nevada. - Eastern Nevada: Ash Springs, Chimney Hot Spring, Duckwater, Hiko Hot Spring, Hot Creek Butte, Iverson Spring, Moon River Hot Spring, Moorman Spring, Railroad Valley, and Williams Hot Spring in eastern Nevada. - Southwestern Nevada?eastern California: Walley’s Hot Spring, Antelope Valley, Fales Hot Springs, Buckeye Hot Springs, Travertine Hot Springs, Teels Marsh, Rhodes Marsh, Columbus Marsh, Alum?Silver Peak, Fish Lake Valley, Gabbs Valley, Wild Rose, Rawhide? Wedell Hot Springs, Alkali Hot Springs, and Baileys/Hicks/Burrell Hot Springs. - Southern Oregon: Alvord Hot Spring, Antelope Hot Spring?Hart Mountain, Borax Lake, Crump Geyser, and Mickey Hot Spring in southern Oregon. - Western Utah: Newcastle, Veyo Hot Spring, Dixie Hot Spring, Thermo, Roosevelt, Cove Fort, Red Hill Hot Spring, Joseph Hot Spring, Hatton Hot Spring, and Abraham?Baker Hot Springs. Structural controls of 426 geothermal systems were analyzed with literature research, air photos, google?Earth imagery, and/or field reviews (Figures 1 and 2). Of the systems analyzed, we were able to determine the structural settings of more than 240 sites. However, we found that many “systems” consisted of little more than a warm or hot well in the central part of a basin. Such “systems” were difficult to evaluate in terms of structural setting in areas lacking in geophysical data. Developed database for structural catalogue in a master spreadsheet. Data components include structural setting, primary fault orientation, presence or absence of Quaternary faulting, reservoir lithology, geothermometry, presence or absence of recent magmatism, and distinguishing blind systems from those that have surface expressions. Reviewed site locations for all 426 geothermal systems– Confirmed and/or relocated spring and geothermal sites based on imagery, maps, and other information for master database. Many systems were mislocated in the original database. In addition, some systems that included several separate springs spread over large areas were divided into two or more distinct systems. Further, all hot wells were assigned names based on their location to facilitate subsequent analyses. We catalogued systems into the following eight major groups, based on the dominant pattern of faulting (Figure 1): - Major normal fault segments (i.e., near displacement maxima). - Fault bends. - Fault terminations or tips. - Step?overs or relay ramps in normal faults. - Fault intersections. - Accommodation zones (i.e., belts of intermeshing oppositely dipping normal faults), - Displacement transfer zones whereby strike?slip faults terminate in arrays of normal faults. - Transtensional pull?aparts. These settings form a hierarchal pattern with respect to fault complexity. - Major normal faults and fault bends are the simplest. - Fault terminations are typically more complex than mid?segments, as faults commonly break up into multiple strands or horsetail near their ends. - A fault intersection is generally more complex, as it generally contains both multiple fault strands and can include discrete di...

  11. A brine interface in the Salton Sea Geothermal System, California: Fluid geochemical and isotopic characteristics

    NASA Astrophysics Data System (ADS)

    Williams, Alan E.; McKibben, Michael A.

    1989-08-01

    Data from 71 geothermal production intervals in 48 wells from the Salton Sea Geothermal System (SSGS) indicate that fluids in that system cluster into two distinct populations in terms of their salinity and their stable isotopic compositions. The distinctive, hot, hypersaline brine (typically >20 wt% total dissolved solids) for which the SSGS is known is overlain by a cooler (<260°C) fluid with distinctly lower salinity (typically <10 wt% total dissolved solids). Hypersaline brines have high and rather consistent 18O shifts produced by water-rock interaction and have a very narrow range in ?D values. Low TDS fluids, on the other hand, show a wide range in both ?D and ?18O. Production of both types of fluid from closely spaced geothermal wells in many regions of the SSGS indicates that a relatively sharp salinity interface exists over much of the field. The fluid interface typically cross-cuts sedimentary bedding but is consistently found where reservoir temperatures are approximately 260°C. At these temperatures, hypersaline brines have densities of approximately 1.0 gm/cm 3, while the low TDS fluids have densities as low as 0.85 gm/cm 3. This stable, density-stratified interface acts as a barrier to convective heat and mass transfer in the SSGS, isolating the hypersaline reservoir from overlying dilute fluids. A lithologic "cap" implied by previous SSGS models is unnecessary in such a stratified system since heat and mass transfer across the interface must occur by slow conductive, diffusional and interface mixing processes regardless of local permeability.

  12. Dixie Valley Engineered Geothermal System Exploration Methodology Project, Baseline Conceptual Model Report

    SciTech Connect

    Iovenitti, Joe

    2014-01-02

    The Engineered Geothermal System (EGS) Exploration Methodology Project is developing an exploration approach for EGS through the integration of geoscientific data. The Project chose the Dixie Valley Geothermal System in Nevada as a field laboratory site for methodology calibration purposes because, in the public domain, it is a highly characterized geothermal system in the Basin and Range with a considerable amount of geoscience and most importantly, well data. The overall project area is 2500km2 with the Calibration Area (Dixie Valley Geothermal Wellfield) being about 170km2. The project was subdivided into five tasks (1) collect and assess the existing public domain geoscience data; (2) design and populate a GIS database; (3) develop a baseline (existing data) geothermal conceptual model, evaluate geostatistical relationships, and generate baseline, coupled EGS favorability/trust maps from +1km above sea level (asl) to -4km asl for the Calibration Area at 0.5km intervals to identify EGS drilling targets at a scale of 5km x 5km; (4) collect new geophysical and geochemical data, and (5) repeat Task 3 for the enhanced (baseline + new ) data. Favorability maps were based on the integrated assessment of the three critical EGS exploration parameters of interest: rock type, temperature and stress. A complimentary trust map was generated to compliment the favorability maps to graphically illustrate the cumulative confidence in the data used in the favorability mapping. The Final Scientific Report (FSR) is submitted in two parts with Part I describing the results of project Tasks 1 through 3 and Part II covering the results of project Tasks 4 through 5 plus answering nine questions posed in the proposal for the overall project. FSR Part I presents (1) an assessment of the readily available public domain data and some proprietary data provided by Terra-Gen Power, LLC, (2) a re-interpretation of these data as required, (3) an exploratory geostatistical data analysis, (4) the baseline geothermal conceptual model, and (5) the EGS favorability/trust mapping. The conceptual model presented applies to both the hydrothermal system and EGS in the Dixie Valley region. FSR Part II presents (1) 278 new gravity stations; (2) enhanced gravity-magnetic modeling; (3) 42 new ambient seismic noise survey stations; (4) an integration of the new seismic noise data with a regional seismic network; (5) a new methodology and approach to interpret this data; (5) a novel method to predict rock type and temperature based on the newly interpreted data; (6) 70 new magnetotelluric (MT) stations; (7) an integrated interpretation of the enhanced MT data set; (8) the results of a 308 station soil CO2 gas survey; (9) new conductive thermal modeling in the project area; (10) new convective modeling in the Calibration Area; (11) pseudo-convective modeling in the Calibration Area; (12) enhanced data implications and qualitative geoscience correlations at three scales (a) Regional, (b) Project, and (c) Calibration Area; (13) quantitative geostatistical exploratory data analysis; and (14) responses to nine questions posed in the proposal for this investigation. Enhanced favorability/trust maps were not generated because there was not a sufficient amount of new, fully-vetted (see below) rock type, temperature, and stress data. The enhanced seismic data did generate a new method to infer rock type and temperature. However, in the opinion of the Principal Investigator for this project, this new methodology needs to be tested and evaluated at other sites in the Basin and Range before it is used to generate the referenced maps. As in the baseline conceptual model, the enhanced findings can be applied to both the hydrothermal system and EGS in the Dixie Valley region.

  13. Performance enhancement of a thermally activated cooling system using microchannel heat exchangers

    Microsoft Academic Search

    Hailei Wang; Richard B. Peterson

    2011-01-01

    In the current study a thermally activated cooling system that combines an ORC system with a vapor compression cooling cycle was developed and tested under laboratory conditions. This combined system can utilize waste heat or other thermal sources such as solar and geothermal to generate power and cooling. Hot oil with temperature up to 200 °C was used as the simulated

  14. Technical support for geopressured-geothermal well activities in Louisiana. Final report, September 27, 1978-December 31, 1980

    SciTech Connect

    Wrighton, F.M.; Bebout, D.; Carver, D.R.; Groat, C.C.; Johnson, A.E. Jr.

    1981-08-31

    The data analysis is based on the Brazoria Texas well and the balance of the modeling work is theoretical. Progress in the regional assessment of the geopressured-geothermal resource in Louisiana is reported. Environmental monitoring effort established monitoring systems and baseline environmental measurements. Efforts to improve the technoeconomic model, improve the estimates of methane in solution, and to evaluate newly identified sites are described. (MHR)

  15. Problems of trace element ratios and geothermometry in a gravel geothermal-aquifer system

    SciTech Connect

    Sonderegger, J.L.; Donovan, J.J.; Ruscetta, C.A.; Foley, D. (eds.)

    1981-05-01

    A Tertiary-age, block-faulted basin in which a Pleistocene gravel bed acts as a confined aquifer and permits the lateral dispersion of the geothermal fluids is studied. Basic data on geology and trace element holes presented previously are reproduced along with fluoride data. Evaluation of the phenomena in this system was attempted using a dissolved silica-enthalpy graph. A chalcedomy curve is also plotted. An enthalpy versus chloride plot suggests that either conductive cooling occurs before mixing or that higher chloride content background waters are available for mixing. (MHR)

  16. Cost Analysis of Environmental Control Systems applicable to Geothermal Energy Development

    SciTech Connect

    None

    1982-08-01

    This report provides an engineering performance and cost correlations from which user could estimate costs of mitigating principal emissions from geothermal power systems. Hydrogen sulfide abatement describes four processes; Iron catalyst, Stretford, EIC, and Dow oxygenation process. Wastewater treatments include: Chemical precipitation, Evaporation ponds, Injection without pretreatment, and Injection with pretreatment. Process and cost estimates are given for Best Case, Most Probable Case, and Worst Case 50 MWe power plant. The cases may be confusing since the worst case has the lowest resource temperature, but the highest loads to mitigate. (DJE 2005)

  17. A review of progress in understanding the fluid geochemistry of the Cerro Prieto geothermal system

    USGS Publications Warehouse

    Truesdell, A.H.; Nehring, N.L.; Thompson, J.M.; Janik, C.J.; Coplen, T.B.

    1984-01-01

    Fluid geochemistry has played a major role in our present understanding of the Cerro Prieto geothermal system. Fluid chemical and isotopic compositions have been used to indicate the origin of water, salts and gases, original subsurface temperature and fluid flow, fluid-production mechanisms, and production-induced aquifer boiling and cold-water entry. The extensive geochemical data and interpretations for Cerro Prieto published from 1964 to 1981 are reviewed and discussed. Fluid geochemistry must continue to play an important role in the further development of the Cerro Prieto field. ?? 1984.

  18. Direct utilization of geothermal heat in cascade application to aquaculture and greenhouse systems at Navarro College. Annual report, January-December 1983

    SciTech Connect

    Smith, K.

    1983-12-30

    Progress is reported on a project for the use of the 130/sup 0/F central Texas geothermal resource. The milestones in the construction of the system for cascading the geothermal enenrgy through two enclosed aquaculture ponds, a greenhouse heating system, and a collection catfish reservoir are reported. (MHR)

  19. Imperial County geothermal development quarterly report, July 1-September 30, 1983

    SciTech Connect

    Not Available

    1983-10-01

    The highlights of geothermal development in Imperial County during July, August, and September 1983 are discussed. Topics include the status of geothermal development projects in the county, geothermal staff activities and research projects, and other geothermal-related topics.

  20. Fracture Propagation and Permeability Change under; Poro-thermoelastic Loads & Silica Reactivity in; Enhanced Geothermal Systems

    Microsoft Academic Search

    Ahmad Ghassemi

    2009-01-01

    Geothermal energy is recovered by circulating water through heat exchange areas within a hot rock mass. Geothermal reservoir rock masses generally consist of igneous and metamorphic rocks that have low matrix permeability. Therefore, cracks and fractures play a significant role in extraction of geothermal energy by providing the major pathways for fluid flow and heat exchange. Therefore, knowledge of the

  1. Rock Mechanics and Enhanced Geothermal Systems: A DOE-sponsored Workshop to Explore Research Needs

    SciTech Connect

    Francois Heuze; Peter Smeallie; Derek Elsworth; Joel L. Renner

    2003-10-01

    This workshop on rock mechanics and enhanced geothermal systems (EGS) was held in Cambridge, Mass., on June 20-21 2003, before the Soil and Rock America 2003 International Conference at MIT. Its purpose was to bring together experts in the field of rock mechanics and geothermal systems to encourage innovative thinking, explore new ideas, and identify research needs in the areas of rock mechanics and rock engineering applied to enhanced geothermal systems. The agenda is shown in Appendix A. The workshop included experts in the fields of rock mechanics and engineering, geological engineering, geophysics, drilling, the geothermal energy production from industry, universities and government agencies, and laboratories. The list of participants is shown is Appendix B. The first day consisted of formal presentations. These are summarized in Chapter 1 of the report. By the end of the first day, two broad topic areas were defined: reservoir characterization and reservoir performance. Working groups were formed for each topic. They met and reported in plenary on the second day. The working group summaries are described in Chapter 2. The final session of the workshop was devoted to reaching consensus recommendations. These recommendations are given in Chapter 3. That objective was achieved. All the working group recommendations were considered and, in order to arrive at a practical research agenda usable by the workshop sponsors, workshop recommendations were reduced to a total of seven topics. These topics were divided in three priority groups, as follows. First-priority research topics (2): {sm_bullet} Define the pre-existing and time-dependent geometry and physical characteristics of the reservoir and its fracture network. That includes the identification of hydraulically controlling fractures. {sm_bullet} Characterize the physical and chemical processes affecting the reservoir geophysical parameters and influencing the transport properties of fractures. Incorporate those processes in reservoir simulators. Second-priority research topics (4): {sm_bullet} Implement and proof-test enhanced fracture detection geophysical methods, such as 3-D surface seismics, borehole seismics, and imaging using earthquake data. {sm_bullet} Implement and proof-test enhanced stress measurement techniques, such as borehole breakout analysis, tilt-meters, and earthquake focal mechanism analysis. {sm_bullet} Implement and proof-test high-temperature down-hole tools for short-term and long-term diagnostics, such as borehole imaging, geophone arrays, packers, and electrical tools.

  2. Active Management of Integrated Geothermal-CO2 Storage Reservoirs in Sedimentary Formations

    DOE Data Explorer

    Buscheck, Thomas A.

    The purpose of phase 1 is to determine the feasibility of integrating geologic CO2 storage (GCS) with geothermal energy production. Phase 1 includes reservoir analyses to determine injector/producer well schemes that balance the generation of economically useful flow rates at the producers with the need to manage reservoir overpressure to reduce the risks associated with overpressure, such as induced seismicity and CO2 leakage to overlying aquifers. Based on a range of well schemes, techno-economic analyses of the levelized cost of electricity (LCOE) are conducted to determine the economic benefits of integrating GCS with geothermal energy production. In addition to considering CO2 injection, reservoir analyses are conducted for nitrogen (N2) injection to investigate the potential benefits of incorporating N2 injection with integrated geothermal-GCS, as well as the use of N2 injection as a potential pressure-support and working-fluid option. Phase 1 includes preliminary environmental risk assessments of integrated geothermal-GCS, with the focus on managing reservoir overpressure. Phase 1 also includes an economic survey of pipeline costs, which will be applied in Phase 2 to the analysis of CO2 conveyance costs for techno-economics analyses of integrated geothermal-GCS reservoir sites. Phase 1 also includes a geospatial GIS survey of potential integrated geothermal-GCS reservoir sites, which will be used in Phase 2 to conduct sweet-spot analyses that determine where promising geothermal resources are co-located in sedimentary settings conducive to safe CO2 storage, as well as being in adequate proximity to large stationary CO2 sources.

  3. Numerical simulations to assess thermal potential at Tauranga low-temperature geothermal system, New Zealand

    NASA Astrophysics Data System (ADS)

    Pearson, S. C. P.; Alcaraz, S. A.; Barber, J.

    2013-12-01

    Tauranga low-temperature geothermal system (New Zealand) has been used for the last 40 years for direct uses including space heating, bathing and greenhouses. Warm-water springs in the area are between 22 and 39 °C, with well temperatures up to 67 °C at 750 m depth. A heat and fluid flow model of the system is used to determine reservoir properties and assess thermal potential. The model covers 130 km by 70 km to 2 km depth, and was calibrated against temperatures measured in 17 wells. Modelling shows that to maintain the observed primarily conductive heat flow regime, bulk permeability is ?2.5 × 10-14 m2 in sedimentary cover and ?1 × 10-16 m2 in the underlying volcanic rocks. The preferred model (R 2 = 0.9) corresponds to thermal conductivities of 1.25 and 1.8 W/m2 for sedimentary and volcanic rocks, respectively, and maximum heat flux of 350 mW/m2. The total surface heat flow is 258 MW over 2,200 km2. Heat flux is highest under Tauranga City, which may be related to inferred geology. Model simulations give insights into rock properties and the dynamics of heat flow in this low-temperature geothermal system, and provide a basis to estimate the effects of extracting hot fluid.

  4. Monitoring of Building Heating and Cooling Systems Based on Geothermal Heat Pump in Galicia (Spain)

    NASA Astrophysics Data System (ADS)

    Iglesias, M.; Rodriguez, J.; Franco, D.

    2012-10-01

    In November 2009 was signed an agreement between Galicia's Government and EnergyLab to develop a project related with the geothermal heatpumps (hereafter, GSHP) technology. That project consisted in replacing the existing thermal equipment generators (diesel boilers and air-water heat pumps) by GSHP systems in representative public buildings: two nursery schools, a university library, a health centre and a residential building. This new systems will reach the demands of existing heating, cooling and domestic hot water (hereafter, DHW). These buildings can serve as examples of energy and economic savings that can offer this technology. We will show detailed analysis of the GSHP facilities monitored, since the starting-up of them. Which includes: COP's, EER's, energy consumption, operating costs, operation hours of the system, economic and emissions comparative, geothermal exchange evolution graphs, environmental conditions evolution graphs (temperature and demands), etc. The results presented show an example of the important benefits of the GSHP technology and the significant savings that can offer its implementation for heating, cooling and DHW production. Note to the reader: The article number has been corrected on web pages on November 22, 2013.

  5. Interactive Maps from the Great Basin Center for Geothermal Energy

    DOE Data Explorer

    The Great Basin Center for Geothermal Energy, part of the University of Nevada, Reno, conducts research towards the establishment of geothermal energy as an economically viable energy source within the Great Basin. The Center specializes in collecting and synthesizing geologic, geochemical, geodetic, geophysical, and tectonic data, and using Geographic Information System (GIS) technology to view and analyze this data and to produce favorability maps of geothermal potential. The interactive maps are built with layers of spatial data that are also available as direct file downloads (see DDE00299). The maps allow analysis of these many layers, with various data sets turned on or off, for determining potential areas that would be favorable for geothermal drilling or other activity. They provide information on current exploration projects and leases, Bureau of Land Management land status, and map presentation of each type of scientific spatial data: geothermal, geophysical, geologic, geodetic, groundwater, and geochemical.

  6. Stragegies to Detect Hidden Geothermal Systems Based on Monitoringand Analysis of CO2 in the Near-Surface Environment

    SciTech Connect

    Lewicki, Jennifer L.; Oldenburg, Curtis M.

    2005-03-29

    We investigate the potential for CO2 monitoring in thenear-surface environment as an approach to exploration for hiddengeothermal systems. Numerical simulations of CO2 migration from a modelhidden geothermal system show that CO2 concentrations can reach highlevels in the shallow subsurface even for relatively low CO2 fluxes.Therefore, subsurface measurements offer an advantage over above-groundmeasurements which are affected by winds that rapidly disperse CO2. Tomeet the challenge of detecting geothermal CO2 emissions within thenatural background variability of CO2, we propose an approach thatintegrates available detection and monitoring techniques with statisticalanalysis and modeling.

  7. Characterization of medium enthalpy geothermal system in the Campania region (southern Italy): from geological data to resource modelling

    NASA Astrophysics Data System (ADS)

    Montegrossi, G.; Inversi, B.; Scrocca, D.; Livani, M.; Petracchini, L.

    2012-04-01

    Within the framework of the VIGOR project, a characterization of medium enthalpy geothermal resources have been carried out in the Campania region (southern Italy), with a focus on the "Guardia dei Lombardi" area (province of Avellino). The VIGOR project began on the basis of an agreement between the Ministry of Economic Development and the Italian National Research Council, and it deal with the exploitation of innovative uses of geothermal energy in the so-called "regions of convergence"(Campania, Calabria, Puglia and Sicilia). Thanks to the intense hydrocarbon exploration, carried out particularly during the 1956-1996 period, an extensive data set made up by deep wells and seismic reflection profiles exist in the study area. The previous exploration demonstrated the presence of a fractured carbonate reservoir, mainly belonging to the Cretaceous section of the Apulian shallow water carbonate platform (e.g. Scrocca 2010 and references therein), which is deformed to shape a buried antiformal stack. The culmination of the uppermost thrust unit reaches a depth of about 200 m SSL (i.e., about 1100 m below the ground level). The reservoir fluids are made up by a CO2 gas cap, which rests above an accumulation of fresh water in the central and upper part of the culmination of the deep carbonatic acquifer (e.g., Monte Forcuso 1 and 2 wells), and a saline water along the flank of the buried anticline (e.g., Bonito 1 Dir, Ciccone 1 wells). Medium enthalpy geothermal resources with a reservoir fluid temperature up to 100°C have been estimated in previous assessments at depth of 2000 m below ground level (ENEL 1987; 1994). However, the presence of thermal springs (e.g. Terme di S. Teodoro) in the area suggests the presence of an active hydraulic circuit and provide further constraints about the geochemical characteristics of the reservoir waters, and the geothermometers investigation (Duchi et al. 1995) give a possible reservoir fluid temperature up to about 124 °C. In this study, the overall reservoir/caprock system structural-stratigraphic setting has been defined based on the integrated interpretation of surface geology, public and available seismic reflection profiles, and composite well logs. In particular, a careful assessment of temperature field at depth has been carried out analyzing the well logs through Horner plot construction (Rider, 1996 and reference therein). Where the temperature data data were scarce or poorly constrained, the approach proposed by Della Vedova, et al. (2001) has been applied. On the basis of well tests, cores and mud losses/absorptions, the reservoir permeability was also re-estimated, confirming quite good permeability values for the fractured carbonate reservoir. One of the main results of this research is the development of an integrated 3D geological model which provides the base for a detailed assessment of the possible geothermal exploitation of the carbonate reservoir. The preliminary results of our analysis suggest that "Guardia dei Lombardi" can be indicated as an interesting area for the geothermal medium enthalpy exploitation, although the presence of the CO2 gas cap and the scaling capability of the deep fluids should be carefully evaluated. From the 3D geological model, we put a sounding basis for a numerical model of hot fluid extraction (made by TOUGH/TOUGHREACT) in which some reasonable hypothesis on the reservoir exploitation may be evaluated.

  8. Comparing FRACHEM and TOUGHREACT for reactive transport modelingof brine-rock interactions in enhanced geothermal systems (EGS)

    SciTech Connect

    Andre, L.; Spycher, N.; Xu, T.; Pruess, K.; Vuataz, F.-D.

    2005-11-15

    Coupled modelling of fluid flow and reactive transport ingeothermal systems is challenging because of reservoir conditions such ashigh temperatures, elevated pressures and sometimes high salinities ofthe formation fluids. Thermal hydrological-chemical (THC) codes, such asFRACHEM and TOUGHREACT, have been developed to evaluate the long-termhydrothermal and chemical evolution of exploited reservoirs. In thisstudy, the two codes were applied to model the same geothermal reservoir,to forecast reservoir evolution using respective thermodynamic andkinetic input data. A recent (unreleased) TOUGHREACT version allows theuse of either an extended Debye-Hu?ckel or Pitzer activity model forcalculating activity coefficients, while FRACHEM was designed to use thePitzer formalism. Comparison of models results indicate that differencesin thermodynamic equilibrium constants, activity coefficients andkinetics models can result in significant differences in predictedmineral precipitation behaviour and reservoir-porosity evolution.Differences in the calculation schemes typically produce less differencein model outputs than differences in input thermodynamic and kineticdata, with model results being particularly sensitive to differences inion-interaction parameters for highsalinity systems.

  9. Thermal and tectonic history in the steamboat hills geothermal field: Determination of the age of active hydrothermal activity by application of AFTA{sup {trademark}} (apatite fission track analysis)

    SciTech Connect

    Duddy, I.R.; Green, P.F. [Geotrack International, Melbourne Univ., Victoria (Australia); Kamp, P.C. van de

    1995-12-31

    This study, in the Steamboat Hills area of the Carson segment of the northern Walker Lane Belt, was initiated to provide a regional thermal history framework and to investigate the age of the active local hydrothermal system. Seven outcrop samples, representing ?Cretaceous granodiorite and ?Triassic Peavine sequence metamorphosed volcanic flow and volcaniclastic rocks plus six samples of Peavine rocks in vertical sequence from an 0.8 km deep geothermal corehole have been analyzed using AFTA (apatite fission track analysis) and zircon fission track analysis.

  10. Geothermal Systems In The Snake River Plain Idaho Characterized By The Hotspot Project

    NASA Astrophysics Data System (ADS)

    Nielson, D. L.; Delahunty, C.; Shervais, J. W.

    2012-12-01

    The Snake River Plain (SRP) is potentially the largest geothermal province in the world. It is postulated that the SRP results from passage of the North American Plate over the Yellowstone mantle plume. This has resulted in felsic, caldera-related volcanism followed by voluminous eruptions of basalt. Compilations of subsurface temperature data demonstrate the masking effect of the Snake River Aquifer. As a consequence, here has been little serious geothermal exploration within the center of the plain; although there are numerous examples of low-temperature fluids, as well as the Raft River geothermal system, on the southern flanks of the SRP. Project Hotspot was designed to investigate the geothermal potential of the SRP through the coring and subsequent scientific evaluation of three holes, each representing a different geothermal environment. These are located at Kimama, north of Burley, in the center of the plain; at Kimberly near Twin Falls on the southern margin of the plain; and at Mountain Home Air Force base in the central part of the western SRP. Both the Kimberly and Mountain Home sites are located in areas that have warm wells and hot springs, whereas, the Kimama site has neither surface nor subsurface thermal manifestations. All of the sites studied here were sampled using slim hole coring techniques in conjunction with a bottom hole temperature probe developed by DOSECC. Our first hole at Kimama in the center of the eastern SRP was cored to a depth of 1,912 m. Temperature measurements showed the SRP fresh water aquifer extends to a depth of 965 m and masks the underlying high temperature gradient of 74.5oC/Km. The core hole at Kimberly reached a depth of 1,959 m and demonstrated a large low-temperature resource of >50oC below 800 m. A core hole at Mountain Home AFB in the eastern SRP reached a depth of 1,821 m and demonstrated the presence of an intermediate- to high-temperature artesian resource that has a clear magmatic association, with measured temperatures of up to 140oC and extrapolated equilibrium temperatures of 150oC. Calculated equilibrium temperatures of the artesian water samples vary from ~134oC to 154oC (Lachmar et al 2012; GRC Transactions). The Kimama hole greatly expanded the depth extent of the Snake River aquifer. However, beneath the masking effect of the aquifer, high temperature gradients were encountered suggesting that high-temperature resources could be present, but their identification could be difficult. The Kimberly hole demonstrated that low-temperature resources along the southern flank of the SRP can have considerable depth extent and are higher volume than previously anticipated. The overall architecture of this large low-temperature system deserves further investigation. Hole MH-2 Mountain Home AFB in the central part of the western SRP has encountered the upper part of a high temperature geothermal resource that also remains to be fully evaluated.

  11. Modular tube bundle heat exchanger and geothermal heat pump system

    SciTech Connect

    Galiyano, M.J.; Wiggs, B.R.; Aspacher, J.T.

    1993-07-06

    An improved ground source heat pump system is described, comprising: an in-ground heat exchanger and a building heat exchanger coupled via conduits for refrigerant to at least one compressor and at least one expander, the compressor having at least one intake line and at least one discharge line, the compressor and the expander being coupled to the conduits such that the refrigerant is circulated in the conduits through pressure changes and corresponding temperature changes in the refrigerant, the in-ground heat exchanger comprising at least one modular tube bundle comprising a plurality of substantially horizontally oriented subterranean tubes, buried in a substantially planar vertical array for installation along substantially vertical walls of at least one that is backfilled for setting the array in thermal engagement with the earth, said at least one bundle having a top and bottom displaced vertically from one another, and the refrigerant being subjected to phase change in the conduits.

  12. Federal Geothermal Research Program Update Fiscal Year 2000

    SciTech Connect

    Renner, J.L.

    2001-08-15

    The Department of Energy's Geothermal Program serves two broad purposes: (1) to assist industry in overcoming near-term barriers by conducting cost-shared research and field verification that allows geothermal energy to compete in today's aggressive energy markets; and (2) to undertake fundamental research with potentially large economic payoffs. The four categories of work used to distinguish the research activities of the Geothermal Program during FY 2000 reflect the main components of real-world geothermal projects. These categories form the main sections of the project descriptions in this Research Update. Exploration Technology research focuses on developing instruments and techniques to discover hidden hydrothermal systems and to explore the deep portions of known systems. Research in geophysical and geochemical methods is expected to yield increased knowledge of hidden geothermal systems. Reservoir Technology research combines laboratory and analytical investigations with equipment development and field testing to establish practical tools for resource development and management for both hydrothermal reservoirs and enhanced geothermal systems. Research in various reservoir analysis techniques is generating a wide range of information that facilitates development of improved reservoir management tools. Drilling Technology focuses on developing improved, economic drilling and completion technology for geothermal wells. Ongoing research to avert lost circulation episodes in geothermal drilling is yielding positive results. Conversion Technology research focuses on reducing costs and improving binary conversion cycle efficiency, to permit greater use of the more abundant moderate-temperature geothermal resource, and on the development of materials that will improve the operating characteristics of many types of geothermal energy equipment. Increased output and improved performance of binary cycles will result from investigations in heat cycle research.

  13. Using Electromagnetic Techniques to Test Models for Shallow Permeability in the Surprise Valley, CA Geothermal System

    NASA Astrophysics Data System (ADS)

    Hawkes, S.; McClain, J. S.; Kahn, A.; Lewis, K.

    2013-12-01

    Surprise Valley in northeastern Modoc County, CA is the westernmost major extensional graben in the northwestern Basin and Range province. There are abundant faults coincident with moderate to boiling temperature hot springs that discharge along the western rim of the valley and in the central eastern part of the valley. Fluid recharge and discharge pathways are poorly understood despite sporadic geothermal exploration, drilling, and development since the 1950's and a wide variety of academic studies that have been focused in the region. It is hypothesized that thermal fluids discharged into the basin exploit fracture permeability related to active extensional faulting along the Surprise Valley Fault (SVF), Lake City Fault Zone (LCFZ), and faults in the Hays Canyon Range (HCR). We present several fault-perpendicular Magnetotelluric profiles conducted across the LCFZ and HCR faults with the goal of imaging the orientation and extent of the geothermal reservoir that supplies the hot springs. Initial results are consistent with the HCR faults tapping a deep conductive aquifer below shallow resistive extrusive igneous rocks, with narrow low resistivity regions beneath the faults. There is no conclusive evidence for or against the LCFZ acting as a preferred fluid pathway, due to relatively homogeneous distribution highly conductive materials and the difficulty in differentiating clay-rich lacustrine sediments from hydrothermal fluids or clays.

  14. Seismic triggering by rectified diffusion in geothermal systems

    NASA Astrophysics Data System (ADS)

    Sturtevant, Bradford; Kanamori, Hiroo; Brodsky, Emily E.

    1996-11-01

    Widespread seismicity was triggered by the June 28, 1992, Landers California, earthquake at a rate which was maximum immediately after passage of the exciting seismic waves. Rectified diffusion of vapor from hydrothermal liquids and magma into bubbles oscillating in an earthquake can increase the local pore pressure to seismically significant levels within the duration of the earthquake. In a hydrothermal system modeled as a two-component H2O-CO2 fluid in porous rock the pressure initially increases linearly with time. The rate of pressure buildup depends sensitively on the mean bubble radius and is large for small bubbles. The diffusion-induced pressure is relaxed by percolation and resorption of vapor into the liquid solution. The induced seismicity itself also relieves stress. Values of parameters used in the present calculations give results consistent with observations of triggered seismicity at Long Valley caldera after the Landers earthquake. For one representative condition, at 250°C and 5.6 km depth, oscillating strain acting on 10-?m-diameter bubbles increases pore pressure at the rate of 151 Pa/s resulting in a pressure increase of 12 kPa in the 80-s duration of the Landers earthquake. The elevated pressure induced by a single 26-m-diameter cloud of bubbles in saturated rock relaxes by percolation through soil of 0.2-mdarcy permeability in 53.6 hours. Observations of earthquake swarms at other locations suggest that self-induced buildup of pore pressure by rectified diffusion can provide a positive feedback mechanism for amplifying seismicity.

  15. Real time seismic traffic light systems for hydraulic stimulations in deep geothermal systems

    NASA Astrophysics Data System (ADS)

    Wegler, Ulrich; Vasterling, Margarete; Dinske, Carsten; Becker, Jan

    2015-04-01

    In order to mitigate the risk associated with induced seismicity caused by hydraulic stimulations in deep geothermal systems so called traffic light systems (risk management plans) are used. These systems consist of a local seismic monitoring and an estimate of the current seismic hazard based on observed induced seismicity. The current hazard is compared to threshold values. Measures to reduce the seismic hazard (e.g. reducing the flow rate) specified in the risk management plan are taken, if thresholds are exceeded. Standard traffic light systems use the largest recorded magnitude or peak ground velocity to estimate current seismic hazard caused by induced earthquakes. We developed a real time technique that computes the probability of exceedance for an undesired magnitude using a statistical analysis of recorded micro-seismicity. Based on the in real time generated earthquake catalogue, we compute the magnitude of completeness, the b-value of the Gutenberg-Richter law, and the so-called seismogenic index. These three quantities are updated in real time, if more induced earthquakes are detected. Using the flow rate of the hydraulic stimulation, which we assume to be recorded in real time as well, we calculate the expected seismicity for the next hours. In particular, we compute the probability of exceedance for a predefined critical magnitude. The value is permanently updated and compared to predefined threshold values of the traffic light system. Additionally to the scenario of a continued stimulation with the current flow rate, we also consider the case of an immediate shut-in. For this scenario the probability of exceedance is computed using a modified Omori law. The developed algorithm is implemented in the real-time earthquake monitoring software SeisComP3 including a graphical user interface. So far the traffic light algorithm has only been tested in playback mode simulating a real time scenario. For example, using data of the Basel Deep Heat Mining project and selecting a probability of exceedance of 60 percent for a critical magnitude of ML = 2.7, our traffic light algorithm turns from green to amber four hours before the first magnitude 2.7 earthquake in Basel, and it turns to red two hours before this event.

  16. Thermal Energy Recovery from Enhanced Geothermal Systems - Evaluating the Potential from Deep, High-Temperature Resources

    NASA Astrophysics Data System (ADS)

    Williams, C.

    2009-12-01

    Enhanced Geothermal Systems (EGS) are geothermal reservoirs that require some form of stimulation to develop the permeability necessary for the circulation of hot water and the recovery of heat for electric power generation. A variety of mechanical, chemical and thermal approaches to reservoir stimulation have been proposed and tested over more than three decades of research on EGS technology, with the primary focus at present on enhancing fracture permeability by elevating fluid pressure sufficiently to induce shear failure along pre-existing natural fractures. A critical issue in assessing the potential EGS resource is quantifying Rg, the geothermal recovery factor, which is defined as the ratio of produced thermal energy to the thermal energy contained in the fractured volume comprising the reservoir. Some published EGS resource assessments incorporate the assumption that a constant amount of thermal energy is recovered during the life of a project, regardless of the temperature of the reservoir, thereby concluding that there is a decrease in Rg with increasing temperature and a reduced potential associated with deep, higher temperature resources. By contrast, production experience and simulations of thermal energy recovery from naturally fractured geothermal reservoirs indicate that Rg , which typically falls in the range from 0.05 to 0.2, is primarily a function of internal reservoir structure, not temperature. Because the thermal energy content of the crust increases linearly with increasing temperature, if the characteristics of Rg for naturally fractured reservoirs apply to EGS reservoirs, proportionally greater resource potential is associated with the deeper, hotter portions of the Earth’s crust, despite the costs and challenges associated with creating and exploiting reservoirs at greater depths and higher temperatures. Both numerical models of EGS thermal energy recovery and studies of analogous naturally fractured reservoirs indicate that Rg will remain relatively constant with increasing depth and temperature, making deep, hot reservoirs more attractive development targets. However, other aspects of production from deep, hot EGS reservoirs need further evaluation, such as the relative effects on productivity of declining fluid viscosity with increasing temperature, fracture closure at higher levels of effective stress, and the increased rates of mineral precipitation and dissolution at higher temperatures.

  17. An efficient finite volume model for shallow geothermal systems. Part I: Model formulation

    NASA Astrophysics Data System (ADS)

    Nabi, M.; Al-Khoury, R.

    2012-12-01

    This series of two papers presents a three-dimensional finite volume model for shallow geothermal systems. In this part, an efficient computational model describing heat and fluid flow in ground-source heat pumps is formulated. The physical system is decomposed into two subdomains, one representing a soil mass, and another representing one or a set of borehole heat exchangers. Optimization of the computational procedure has been achieved by, first, using a pseudo three-dimensional line element for modeling the borehole heat exchanger, and second, using a combination of a locally refined Cartesian grid and a multigrid with hierarchal tree data structure for discretizing and solving the soil mass governing equations. This optimization made the model computationally efficient and capable of simulating multiple borehole heat exchangers embedded in a multilayer system, in relatively short CPU time. In Part II of this series, verifications and numerical examples describing the computational capabilities of the model are presented.

  18. Direct utilization of geothermal heat in cascade application to aquaculture and greenhouse systems at Navarro College. Annual report, January-December 1982

    SciTech Connect

    Smith, K.

    1982-12-31

    Progress is reported on a project for the use of the 130/sup 0/F central Texas geothermal resource. The revised project consists of cascading the geothermal energy through two enclosed aquaculture ponds, a greenhouse heating system, and into a collection catfish reservoir. (MHR)

  19. Thermal structure and fluid phase states in high-enthalpy geothermal systems as sensors of crustal permeability

    NASA Astrophysics Data System (ADS)

    Driesner, T.; Weis, P.

    2012-12-01

    High-enthalpy geothermal systems show distinct thermal structures and fluid phase state distributions (single phase vs. boiling regions). These can be rationalized in terms of the phase diagram of water in pressure-enthalpy space (Fig. 1). Numerical simulations using the HYDROTHERM and CSMP++ simulation platforms showed that system-scale permeability and the closure of permeability at higher temperatures near the magmatic heat source are the key parameter that controls this behavior (Hayba & Ingebritsen, 1997; Driesner & Geiger, 2007). Interestingly, thermal profiles that resemble those measured in natural systems only emerged when simulations were run with constant background permeability. Depth-dependent background permeability as suggested by Ingebritsen&Manning does not lead to observed profiles. The most likely interpretation is that the depth-dependent permeability model applies to a crust that is in a steady state with respect to a competition between permeability creation by failure and permeability in response to strain and chemical fluid-rock interaction while in geothermal systems high fluid pressure leads to elevated transient permeability. We suggest that the thermal structure and fluid phase state distribution in geothermal systems are measures of the sytem-scale permeability. They may be useful in better constraining parameters of empirical permeability models.pflow paths of geothermal fluids in a pressure-enthalpy phase diagram of water as a function of permeability: (A) 10-16 m2, (B) 10-15 m2, (C) 10-14 m2.

  20. An integrated multidisciplinary re-evaluation of the geothermal system at Valles Caldera, New Mexico, using an immersive three-dimensional (3D) visualization environment

    NASA Astrophysics Data System (ADS)

    Fowler, A.; Bennett, S. E.; Wildgoose, M.; Cantwell, C.; Elliott, A. J.

    2012-12-01

    We describe an approach to explore the spatial relationships of a geothermal resource by examining diverse geological, geophysical, and geochemical data sets using the immersive 3-dimensional (3D) visualization capabilities of the UC Davis Keck Center for Active Visualization in the Earth Sciences (KeckCAVES). The KeckCAVES is a facility where stereoscopic images are projected onto four, surfaces (three walls and a floor), which the user perceives as a seamless 3D image of the data. The user can manipulate and interact with the data, allowing a more intuitive interpretation of data set relationships than is possible with traditional 2-dimensional techniques. We incorporate multiple data sets of the geothermal system at Valles Caldera, New Mexico: topography, lithology, faults, temperature, alteration mineralogy, and magnetotellurics. With the ability to rapidly and intuitively observe data relationships, we are able to efficiently and rapidly draw conclusions about the subsurface architecture of the Valles Caldera geothermal system. We identify two high-temperature anomalies, one that corresponds with normal faults along the western caldera ring fracture, and one that with the resurgent dome. A cold-temperature anomaly identified adjacent to the resurgent dome high-temperature anomaly appears to relate to a fault controlled graben valley that acts as a recharge zone, likely funneling cold meteoric water into the subsurface along normal faults observed on published maps and cross sections. These high-temperature anomalies broadly correspond to subsurface regions where previous magnetotelluric studies have identified low apparent resistivity. Existing hot springs in the Sulfur Springs area correspond to the only location where our modeled 100°C isotherm intersects the ground surface. Correlation between the first occurrence of key alteration minerals (pyrite, chlorite, epidote) in previously drilled boreholes and our temperature model vary, with chlorite showing a strong correlation with a model temperature of ~120°C. In summary, the application of immersive 3D modeling can provide industry with a method to make informed assessments of the location and volume of a geothermal system and a cost-effective approach during exploration and developmentblique view from beneath the Valles Caldera geothermal system, visualized in the 3D immersive KeckCAVES facility at UC Davis. View is looking up to the southwest. Data from previously drilled temperature boreholes (red lines) were used to calculate temperature isotherms (100°C-blue; 150°C-green; 200°C-yellow; 250°C-red).

  1. Imaging the Roots of Geothermal Systems: 3-D Inversion of Magnetotelluric Array Data in the Taupo Volcanic Zone, New Zealand

    NASA Astrophysics Data System (ADS)

    Bertrand, E. A.; Caldwell, G.; Bannister, S. C.; Hill, G.; Bennie, S.

    2013-12-01

    The Taupo Volcanic Zone (TVZ), located in the central North Island of New Zealand, is a rifted arc that contains more than 20 liquid-dominated high-temperature geothermal systems, which together discharge ~4.2 GW of heat at the surface. The shallow (upper ~500 m) extent of these geothermal systems is marked by low-resistivity, mapped by tens-of-thousands of DC resistivity measurements collected throughout the 1970's and 80's. Conceptual models of heat transport through the brittle crust of the TVZ link these low-resistivity anomalies to the tops of vertically ascending plumes of convecting hydrothermal fluid. Recently, data from a 40-site array of broadband seismometers with ~4 km station spacing, and an array of 270 broadband magnetotelluric (MT) measurements with ~2 km station spacing, have been collected in the south-eastern part of the TVZ in an experiment to image the deep structure (or roots) of the geothermal systems in this region. Unlike DC resistivity, these MT measurements are capable of resolving the resistivity structure of the Earth to depths of 10 km or more. 2-D and 3-D models of subsets of these MT data have been used to provide the first-ever images of quasi-vertical low-resistivity zones (at depths of 3-7 km) that connect with the near-surface geothermal fields. These low-resistivity zones are interpreted to represent convection plumes of high-temperature fluids ascending within fractures, which supply heat to the overlying geothermal fields. At the Rotokawa, Ngatamariki and Ohaaki geothermal fields, these plumes extend to a broad layer of low-resistivity, inferred to represent a magmatic, basal heat source located below the seismogenic zone (at ~7-8 km depth) that drives convection in the brittle crust above. Little is known about the mechanisms that transfer heat into the hydrothermal regime. However, at Rotokawa, new 3-D resistivity models image a vertical low-resistivity zone that lies directly beneath the geothermal field. The top of this low-resistivity zone (at ~3 km depth where temperatures are greater than 330°C) coincides with a cluster of seismicity that may mark the top of the brittle-ductile transition zone. Thus, we may be imaging the contact between the underlying ';volcanic' and the upper ';geothermal' system, at a depth (~4 km) that is much shallower than expected.

  2. Session 1: Geothermal Pumping Systems and Two-Phase Flow Studies

    SciTech Connect

    Hanold, R.J.

    1983-12-01

    Improvements in electric submersible pumping systems have resulted in a demonstrated downhole running life of one year for low horsepower units operating in 180 C brine. The implementation of a prototype pressurized lubrication system to prevent brine intrusion and loss of lubricating oil from the motor and protector sections has been successfully tested. Second generation pressurized lubrication systems have been designed and fabricated and will be utilized in downhole production pumping tests during FY84. Pumping system lifetime is currently limited by available power cable designs that are degraded by high-temperature brine. A prototype metal-sheathed power cable has been designed and fabricated and is currently undergoing destructive and nondestructive laboratory testing. This cable design has the potential for eliminating brine intrusion into the power delivery system through the use of a hermatically sealed cable from the surface to the downhole motor. The two-phase flow program is directed at understanding the hydrodynamics of two-phase flows. The two-phase flow regime is characterized by a series of flow patterns that are designated as bubble, slug, churn, and annular flow. Churn flow has received very little scientific attention. This lack of attention cannot be justified because calculations predict that the churn flow pattern will exist over a substantial portion of the two-phase flow zone in producing geothermal wells. The University of Houston is experimentally investigating the dynamics of churn flow and is measuring the holdup over the full range of flow space for which churn flow exists. These experiments are being conducted in an air/water vertical two-phase flow loop. Brown University has constructed and is operating a unique two-phase flow research facility specifically designed to address flow problems of relevance to the geothermal industry. An important feature of the facility is that it is dedicated to two-phase flow of a single substance (including evaporation and condensation) as opposed to the case of a two-component two-phase flow. This facility can be operated with horizontal or vertical test sections of constant diameter or with step changes in diameter to simulate a geothermal well profile.

  3. Thermo-Hydro-Mechanical-Chemical Coupled Modeling of Geothermal Doublet Systems in Limestones

    NASA Astrophysics Data System (ADS)

    Rühaak, Wolfram; Pei, Liang; Heldmann, Claus-Dieter; Bartels, Jörn; Sass, Ingo

    2015-04-01

    Limestone aquifers in Southern Germany have been used within the last decade very successfully for geothermal heating and - to a lesser extent - for power generation. As an example the region around Munich has been extensively explored. While the extent of usage of this reservoir is increasing there is also an increased interest in better understanding of the reservoir properties and its change in the course of operation. For instance, the observed production and injection pressures are partly hard to explain. They may be related to mechanical or chemical processes, or both. Based on extensive data of outcrop studies and drillings, a data-base for the relevant physical properties of the respective limestones has been complied. The data include thermal conductivity, density, specific heat capacity, permeability, as well as mechanical properties like thermal expansion coefficient and elasticity modules. By using the hydro-thermo-chemical simulator FEFLOW together with an extension for thermo- and hydro-mechanical coupling the relevant processes are studied and compared with observed data. Conclusions for an optimized operation of geothermal systems in limestones are given and discussed.

  4. The effect of CO{sub 2} on reservoir behavior for geothermal systems

    SciTech Connect

    Gaulke, S.W.

    1986-12-01

    The purpose was to gain an understanding of the effects of non-condensible gases (CO/sub 2/) in fractured two-phase geothermal systems. A thorough review of previous work on non-condensible gases was carried out. In addition, since the flowing mass fraction of CO/sub 2/ is strongly controlled by the flowing saturation, the flowing enthalpy literature was also reviewed. Numerical techniques were employed to examine how non-condensible gases (CO/sub 2/) affect well transients and to determine the value of these effects as tools to evaluate in situ reservoir parameters. Simplified reservoir models were used to define the effects of CO/sub 2/ in the reservoir and the resulting transient behavior at the feedzones to the well. Furthermore, fracture-matrix interaction was studied in detail to identify the effects of CO/sub 2/ on recovery and flow patterns within the reservoir. The insight gained from the sensitivity studies for enthalpy and CO/sub 2/ transients was applied to interpret transient data from well BR21 at the Broadlands geothermal field of New Zealand.

  5. Delineation of the High Enthalpy Reservoirs of the Sierra Nevada Volcanic Geothermal System, South-Central Chile

    NASA Astrophysics Data System (ADS)

    Alam, M.; Muñoz, M.; Parada, M.

    2011-12-01

    Geothermal system associated with the Pleistocene-Holocene Sierra Nevada volcano (SNVGS) in the Araucanía Region of Chile has surface manifestations from the north-western flank of the volcano, up to Manzanar and Malalcahuello. Baños del Toro, located on the northwestern flank of the volcano, has numerous fumaroles and acid pools (acid sulfate waters, T=~90°C, pH=2.1, TDS=3080 mg/L); while Aguas de la Vaca, near the base of the volcano, has a bubbling spring (chloride-sulfate waters, T=~60°C, pH=7.0, TDS=950 mg/L). Five shallow (<120m) wells (2 at Manzanar and 3 at Malalcahuello) dug and drilled in the Cautín River Valley discharge alkaline (pH= 9-10) waters with relatively low TDS (130-210mg/L). The main heat source of the geothermal system is apparently the magmatic system of the Sierra Nevada volcano. Liquiñe-Ofqui Fault Zone (LOFZ) that transects the area forms excellent conduits for the flow of the geothermal waters. The geothermal reservoirs are hosted in the volcanic rocks interceded with glacial deposits over the North Patagonian Batholith that forms an impermeable barrier, and thus constitutes the lower boundary of the geothermal system and also controls the lateral flow of the fluids. An equilibrium temperature of ~210°C is derived from gas geothermometry (CO2/Ar-H2/Ar) of the discharges at Baños del Toro. Geothermal fluids from the upflow area on the northwestern flank of the volcano migrate northwards to the Cautín River Valley. The geothermal system has a high enthalpy reservoir(s) on the northwestern flank of the Sierra Nevada volcano and low-enthalpy reservoirs in the Cautín River Valley that have been tapped to form spas at Manzanar and Malalcahuello. While sub-vertical fractures of LOFZ facilitate the recharge of the system, lateral flow of the geothermal fluids is apparently controlled by lithology; Melipueclo Pluton in particular prevents the westward flow from the upflow zone, causing the flow only northwards to Malalcahuello and subsequently westward on meeting poorly permeable Guapitrío Member of the Cura-Mallín Formation. This change in the flow direction from northwestward up to Malalcahuello to westward towards Manzanar is supported by topographic and hydrographic conditions as well, besides available geological and geophysical data. SNVGS is perhaps the most promising geothermal system in the area, considering the presence of high enthalpy reservoir and stable heat source, ideal for its development as geothermal resource. Acknowledgments: Authors would like to acknowledge the funding for this work through the PBCT PDA-07 project of CONICYT and Geothermal Program (Cátedra de Geotermia) of the Ministry of Energy and Mining, Government of Chile.

  6. Potential impacts of artificial intelligence expert systems on geothermal well drilling costs:

    SciTech Connect

    Satrape, J.V.

    1987-11-24

    The Geothermal research Program of the US Department of Energy (DOE) has as one of its goals to reduce the cost of drilling geothermal wells by 25 percent. To attain this goal, DOE continuously evaluates new technologies to determine their potential in contributing to the Program. One such technology is artifical intelligence (AI), a branch of computer science that, in recent years, has begun to impact the marketplace in a number of fields. Expert systems techniques can (and in some cases, already have) been applied to develop computer-based ''advisors'' to assist drilling personnel in areas such as designing mud systems, casing plans, and cement programs, optimizing drill bit selection and bottom hole asssembly (BHA) design, and alleviating lost circulation, stuck pipe, fishing, and cement problems. Intelligent machines with sensor and/or robotic directly linked to AI systems, have potential applications in areas of bit control, rig hydraulics, pipe handling, and pipe inspection. Using a well costing spreadsheet, the potential savings that could be attributed to each of these systems was calculated for three base cases: a dry steam well at The Geysers, a medium-depth Imerial Valley well, and a deep Imperial Valley well. Based on the average potential savings to be realized, expert systems for handling lost circulations problems and for BHA design are the most likely to produce significant results. Automated bit control and rig hydraulics also exhibit high potential savings, but these savings are extremely sensitive to the assumptions of improved drilling efficiency and the cost of these sytems at the rig. 50 refs., 19 figs., 17 tabs.

  7. Novel thermophilic sulfate-reducing bacteria from a geothermally active underground mine in Japan.

    PubMed

    Kaksonen, Anna H; Plumb, Jason J; Robertson, Wendy J; Spring, Stefan; Schumann, Peter; Franzmann, Peter D; Puhakka, Jaakko A

    2006-05-01

    Thermophilic sulfate-reducing bacteria were enriched from samples obtained from a geothermal underground mine in Japan. The enrichment cultures contained bacteria affiliated with the genera Desulfotomaculum, Thermanaeromonas, Thermincola, Thermovenabulum, Moorella, "Natronoanaerobium," and Clostridium. Two novel thermophilic sulfate-reducing strains, RL50JIII and RL80JIV, affiliated with the genera Desulfotomaculum and Thermanaeromonas, respectively, were isolated. PMID:16672530

  8. Accelerated Geothermal Resource Development in the Great Basin Through Enhanced Public Awareness and Outreach to Shareholders.

    SciTech Connect

    Taranik, James V.; Oppliger, Gary; Sawatsky, Don

    2002-04-10

    The Great Basin Center for Geothermal Energy conducted work encompassing two main tasks. We (1) produced a web-based, stakeholder geothermal information system for Nevada geothermal data relevant to assessing and developing geothermal resources, and (2) we held informational stakeholder workshops (both as part of GeoPowering the West Initiative). The objective of this grant was to conduct workshops and fund database and web development activities. This grant funds salaries for web and database developers and part of the administrative assistant who helps to coordinate and organize workshops, and maintain selected databases.

  9. 2008 Geothermal Technologies Market Report

    SciTech Connect

    Cross, J.; Freeman, J.

    2009-07-01

    This report describes market-wide trends for the geothermal industry throughout 2008 and the beginning of 2009. It begins with an overview of the U.S. DOE's Geothermal Technology Program's (GTP's) involvement with the geothermal industry and recent investment trends for electric generation technologies. The report next describes the current state of geothermal power generation and activity within the United States, costs associated with development, financing trends, an analysis of the levelized cost of energy (LCOE), and a look at the current policy environment. The report also highlights trends regarding direct use of geothermal energy, including geothermal heat pumps (GHPs). The final sections of the report focus on international perspectives, employment and economic benefits from geothermal energy development, and potential incentives in pending national legislation.

  10. Liu, Rees and Spitler. 1 Simulation of a Geothermal Bridge Deck Anti-icing System and Experimental Validation

    E-print Network

    Liu, Rees and Spitler. 1 Simulation of a Geothermal Bridge Deck Anti-icing System and Experimental Validation Xiaobing Liu Simon J. Rees* Jeffrey D. Spitler Oklahoma State University, School of Mechanical/04/02 Word Count: 5030 TRB 2003 Annual Meeting CD-ROM Paper revised from original submittal. #12;Liu, Rees

  11. Thermal and hydrochemical anomalies due to large-scale thermohaline convection in Seferihisar-Balçova Geothermal system, Western Anatolia, Turkey

    Microsoft Academic Search

    F. Magri; A. Pekdeger; Gemici; T. Akar

    2009-01-01

    The Seferihisar-Balçova Geothermal system (SBG), Western Anatolia, Turkey, is characterized by complex temperature and hydrochemical anomalies which causes are not fully understood. Previous geophysical investigations suggested that hydrothermal convection in the faulted areas of the SBG and recharge flow from the Horst may be possible transport mechanisms underlying the observed patterns. A numerical model of thermohaline flow along a North-South

  12. Life Cycle Water Consumption and Water Resource Assessment for Utility-Scale Geothermal Systems: An In-Depth Analysis of Historical and Forthcoming EGS Projects

    SciTech Connect

    Schroeder, Jenna N.

    2013-08-31

    This report is the third in a series of reports sponsored by the U.S. Department of Energy Geothermal Technologies Program in which a range of water-related issues surrounding geothermal power production are evaluated. The first report made an initial attempt at quantifying the life cycle fresh water requirements of geothermal power-generating systems and explored operational and environmental concerns related to the geochemical composition of geothermal fluids. The initial analysis of life cycle fresh water consumption of geothermal power-generating systems identified that operational water requirements consumed the vast majority of water across the life cycle. However, it relied upon limited operational water consumption data and did not account for belowground operational losses for enhanced geothermal systems (EGSs). A second report presented an initial assessment of fresh water demand for future growth in utility-scale geothermal power generation. The current analysis builds upon this work to improve life cycle fresh water consumption estimates and incorporates regional water availability into the resource assessment to improve the identification of areas where future growth in geothermal electricity generation may encounter water challenges.

  13. Life Cycle Water Consumption and Water Resource Assessment for Utility-Scale Geothermal Systems: An In-Depth Analysis of Historical and Forthcoming EGS Projects

    DOE Data Explorer

    Schroeder, Jenna N.

    This report is the third in a series of reports sponsored by the U.S. Department of Energy Geothermal Technologies Program in which a range of water-related issues surrounding geothermal power production are evaluated. The first report made an initial attempt at quantifying the life cycle fresh water requirements of geothermal power-generating systems and explored operational and environmental concerns related to the geochemical composition of geothermal fluids. The initial analysis of life cycle fresh water consumption of geothermal power-generating systems identified that operational water requirements consumed the vast majority of water across the life cycle. However, it relied upon limited operational water consumption data and did not account for belowground operational losses for enhanced geothermal systems (EGSs). A second report presented an initial assessment of fresh water demand for future growth in utility-scale geothermal power generation. The current analysis builds upon this work to improve life cycle fresh water consumption estimates and incorporates regional water availability into the resource assessment to improve the identification of areas where future growth in geothermal electricity generation may encounter water challenges.

  14. Assessment of the State-Of-The-Art of Numerical Simulation of Enhanced Geothermal Systems

    SciTech Connect

    None

    1999-11-01

    The reservoir features of importance in the operation of enhanced geothermal systems are described first (Section 2). The report then reviews existing reservoir simulators developed for application to HDR reservoirs (Section 3), hydrothermal systems (Section 4), and nuclear waste isolation (Section 5), highlighting capabilities relevant to the evaluation and assessment of EGS. The report focuses on simulators that include some representation of flow in fractures, only mentioning other simulators, such as general-purpose programs or groundwater models (Section 6). Following these detailed descriptions, the report summarizes and comments on the simulators (Section 7), and recommends a course of action for further development (Section 8). The references are included in Section 9. Appendix A contains contractual information, including a description of the original and revised scope of work for this study. Appendix B presents comments on the draft report from DOE reviewer(s) and the replies of the authors to those comments. [DJE-2005

  15. Geothermal Energy

    SciTech Connect

    Steele, B.C.; Harman, G.; Pitsenbarger, J. [eds.] [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.

  16. Geothermal Energy.

    ERIC Educational Resources Information Center

    Reed, Marshall J.

    1979-01-01

    During 1978, exploration for geothermal energy continued at the same moderately low level of the past few years in most countries. The U.S. is the only country where the development of geothermal energy depends on private industry. (BB)

  17. FINAL REPORT ENHANCED GEOTHERMAL SYSTEMS TECHNOLOGY PHASE II ANIMAS VALLEY, NEW MEXICO

    SciTech Connect

    Roy A.Cunniff; Roger L. Bowers

    2003-12-29

    Final Technical Report covering siting, permitting, and drilling two geothermal temperature gradient holes. This report provides a summary of geotechnical and geophysical data that led to the siting, drilling, and completion of 2 temperature gradient holes in the geothermal anomaly at Lightning Dock Known Geothermal Resource Area in the Animas Valley of New Mexico. Included in this report is a summary of institutional factors and data defining the well drilling process and acquiring drilling permits. Data covering the results of the drilling and temperature logging of these two holes are provided. The two gradient holes were sited on federal geothermal leases owned by Lightning Dock Geothermal, Inc. and both holes were drilled into lakebed sediments some distance from the intense shallow geothermal anomaly located in the eastern half of Section 7, Township 25 South, Range 19 West.

  18. Geothermal Data via the Virginia Tech and DMME Portal to the National Geothermal Data System for the Eastern and Southeastern United States from the Regional Geophysics Laboratory of Virginia Polytechnic Institute and State University

    DOE Data Explorer

    The former title for this record was "Geothermal Data for the Eastern and Southeastern U.S. from the Regional Geophysics Laboratory of Virginia Tech." The content originally referenced is still available. It includes geothermal maps of seven southeastern states with accompanying data tables. The seven states are: New Jersey, Maryland, Delaware, Virginia, North Carolina, South Caroline, and Georgia. Data types include geothermal data, seismic data, and magnetic and gravity data. Typical geothermal data may include tables of temperature versus depth data, plots of temperature/gradient versus depth, tables of thermal conductivity data, and tables of gamma log data. Other resources available from the RGL provide information about hot springs in the southeastern U.S., temperatures for Atlantic Coastal Plain sediments, and deep fracture permeability in crystalline rocks in the eastern and southeastern U.S. Recently, this website and its collection of geothermal data has been renamed and reorganized as a portal into the National Geothermal Data System, a move that makes far more data both available and integrated.

  19. Microseismic Activity in Low-Hazard Geothermal Settings in Southern Germany

    NASA Astrophysics Data System (ADS)

    Megies, T.; Wassermann, J. M.

    2010-12-01

    In the last few years several geothermal power plants have taken up production in southern Germany and many more are currently in exploration or construction stages. One of the most promising areas in Germany with respect to geothermal exploitation is the Bavarian Molasse Basin: A karstified limestone formation at a few kilometers depth provides sufficiently high temperatures also for power production and its high permeability obviates the need for hydraulic stimulation of the reservoir. Furthermore the local setting is being considered as generally aseismic with very sparse and weak seismicity. The seismic hazard going along with production is therefore being considered negligible and no particular efforts for seismic monitoring were made. In 2008, however, an unexpected Ml 2.3 event which was felt by locals attracted public attention. With no stations near the epicenter, the event still was located in the general vicinity of a geothermal plant that took up production about half a year earlier. In the last two years a temporary network was set up that recorded more than thirty events with magnitudes mainly ranging from Ml 0 to 1.5. The data recorded in the local network are used for absolute locations. A high resolution 3-D P-wave velocity model is constructed from data of a dense 3-D seismic survey conducted to image the geothermal reservoir. An S-wave velocity model is compiled from converted shear waves, an old survey with shear wave excitation and cluster analysis of Vp/Vs ratios using the recorded events. Results show the hypocenters close to the bottom of the injection well. Results of waveform similarity analysis and clustering of events are presented along with preliminary results of further work focusing on hypocenter relocation via master-slave analysis and differential location techniques. Still, the exact extent of the man-made influence on the seismicity remains arguable. Events below magnitude 1.5 could not be detected prior to the production of the geothermal plant in the main network of the local earthquake service. Questions also remain as to the unique features of this geothermal site in comparison with others not far away that do not produce notable induced seismicity. How the fault targeted by the well is oriented in the present-day stress field is suspected to have a major impact on fault reactivation. An upcoming field experiment is about to address these open questions and test some working hypotheses. It is located at another geothermal reservoir in a very similar setting where a geothermal power plant is currently in the construction stage. In addition to monitoring the production stage, we intend to collect one year of pre-production data of the unperturbed reservoir. This will enable us to better assess the influence of fluid injections on local seismicity at geothermal plants and will lead to a better understanding of the reasons for the observed microseismicity.

  20. Excretory System Activity

    NSDL National Science Digital Library

    2012-06-12

    This activity from Darcy Hartley-Pinard will help elementary school teachers demonstrate the structures and process of the excretory system. The class will use a diagram of a human body and everyday items including straws, uncooked spaghetti, yarn and kidney beans to recreate the veins, arteries, kidneys, ureters, bladder and urethra. This activity is useful for younger students to visualize and connect with the processes that take place in their own bodies.

  1. Quartz dissolution and silica deposition in hot-dry-rock geothermal systems

    SciTech Connect

    Robinson, B.A.

    1982-07-01

    The kinetics of quartz dissolution control the produced fluid dissolved silica concentration in geothermal systems in which the downhole residence time is finite. The produced fluid of the Phase I, Run Segment 5 experimental Hot Dry Rock (HDR) geothermal system at Fenton Hill, NM, was undersaturated with respect to quartz in one pass through the reservoir, suggesting that the rate of granite dissolution governed the outlet dissolved silica concentration in this system. The literature data for the rate of quartz dissolution in water from 65 to 625/sup 0/C is correlated using an empirical rate law which is first order in quartz surface area and degree of undersaturation of the fluid. The Arrhenius plot (ln k vs T/sup -1/) is linear over eight orders of magnitude of the rate constant, verifying the validity of the proposed rate expression. Carefully performed quartz dissolution experiments in the present study duplicated the literature data and completed the data base in the temperature range from 150 to 250/sup 0/C. Identical experiments using crushed granite indicate that the rate of quartz dissolution in the presence of granite could be as much as 1 to 2 orders of magnitude faster than the rates observed in the pure quartz experiments. A temperature dependent HDR reservoir model incorporates the quartz dissolution rate law to simulate the dissolved silica behavior during the Fenton Hill Run Segment 5 experiment. For this low-permeability, fracture-dominated reservoir, the assumptions of one-dimensional plug flow through a vertically-inclined rectangular fracture and one-dimensional rock heat conduction perpendicular to the direction of flow are employed. These simplifications lead to an analytical solution for the temperature field in the reservoir.

  2. Analysis of a combined photovoltaic–geothermal gas-fired absorption heat pump system in a Canadian climate

    Microsoft Academic Search

    Michaël Kummert; Michel Bernier

    2008-01-01

    This study examines the technical feasibility of using a geothermal gas-fired absorption heat pump (A-GSHP) for space conditioning and domestic hot water heating in a Canadian climate. The A-GSHP is coupled to a photovoltaic (PV) system with battery storage intended to ensure the full autonomy of the heating, ventilating and air conditioning (HVAC) system from the electric grid. The system

  3. ANALYSIS OF GEOTHERMAL WASTES FOR HAZARDOUS COMPONENTS

    EPA Science Inventory

    Regulations governing the disposal of hazardous wastes led to an assessment for geothermal solid wastes for potentially hazardous properties. Samples were collected from three active geothermal sites in the western United States: The Geysers, Imperial Valley, and northwestern Nev...

  4. Magmatic gases in well fluids aid the mapping of the flow pattern in a geothermal system

    NASA Astrophysics Data System (ADS)

    Armannsson, H.; Gislason, G.; Hauksson, T.

    1982-02-01

    Gas composition and silica concentrations of well fluids are used in conjunction with pressure, temperature and enthalpy data to obtain a model of the drilled part of the Krafla geothermal field (Northeast Iceland). A magma chamber is located at 3-8 km depth under the field. Magmatic gases emanate from the chamber and travel via a channel reaching the surface at the Hveragil eruptive fissure. The composition of the gases is apparently modified on the way, in that sulphur, which presumably is in the form of sulphur dioxide to begin with, is removed, and what remains is in the form of hydrogen sulphide. It is suggested that the major removal mechanism is the deposition of pyrite and pyrrhotite during the passage of the gases through the hydrothermal system.

  5. Environmental Constraints on the Distribution, Diversity, and Activity of Biological Nitrogen Fixation in the Yellowstone Geothermal Complex

    NASA Astrophysics Data System (ADS)

    Boyd, E.; Hamilton, T. L.; Peters, J. W.

    2010-12-01

    Biological nitrogen fixation is a keystone process in many ecosystems, providing bio-available forms of fixed nitrogen for members of the community. Degenerate primers targeting the known diversity of the nitrogenase protein-encoding gene (nifH) were designed and employed to investigate the physical and chemical parameters that underpin the distribution and diversity of nifH as a proxy for nitrogen-fixing organisms in the geothermal springs of Yellowstone National Park (YNP), Wyoming. nifH was detected in 57 of 64 YNP springs that varied in pH from 1.90 to 9.78 and temperature from 16C to 89C, suggesting that the distribution of nifH in YNP is widespread and is not constrained by pH and temperature alone. Phylogenetic and statistical analysis of nifH recovered from 13 different spring types reveals evidence for both geographical and ecological structure in nifH communities. Model selection indicated that the phylogenetic relatedness of nifH assemblages could be best explained by the geographic distance between sample sites. This suggests that nifH assemblages are dispersal limited with respect to the fragmented nature of the YNP geothermal spring environment. The second highest ranking explanatory model for predicting the phylogenetic relatedness of nifH assemblages was spring water conductivity (a proxy for salinity), suggesting that salinity imposes phylogenetic niche conservatism on nitrogen-fixing populations inhabiting YNP springs. In a number of cases, nifH genes were detected in environments previously unknown to harbor diazotrophic microorganisms, including high temperature (>70C) and acidic (pH < 3.5) geothermal springs. To determine if the organisms harboring these genes were capable of reducing N2 under ambient conditions, a number of in situ and ex situ assays were performed. Acetylene reduction, selective enrichment, and stable isotope incorporation assays collectively suggest the presence of active N2 fixing populations in several representative high temperature acid springs. Ex situ enrichment assays indicate that the populations are specifically adapted to local conditions. Genetic characterization of nifH genes recovered from a representative enrichment and a high temperature acid spring from where the enrichment originated indicate that the diazotrophic population is most closely affiliated to uncultivated members of the Proteobacteria. Collectively these studies provide new insight into environmental constraints that underpin the distribution, diversity, and activity of diazotrophs in geothermal environments. Furthermore, this study extends the upper temperature limit for nitrogen fixation in a terrestrial environment, and arguably represents the most extreme environmental conditions that support diazotrophic growth determined to date.

  6. Technical support for geopressured-geothermal well activities in Louisiana; Final report, 1 January 1992--31 December 1993

    SciTech Connect

    John, C.J.

    1994-01-01

    The US Department of Energy has operated continuous-recording, microearthquake monitoring networks at geopressured-geothermal test well sites since 1980. These microseismic networks were designed to detect microearthquakes indicative of fault activation and/or subsidence that can potentially result from the deep subsurface withdrawal and underground disposal of large volumes of brine during well testing. Seismic networks were established before the beginning of testing to obtain background levels of seismicity. Monitoring continued during testing and for some time after cessation of flow testing to assess any delayed microseismicity caused by the time dependence of stress migration within the earth. No flow testing has been done at the Hulin well since January 1990, and the Pleasant Bayou well has been shut down since September 1992. Microseismic monitoring continued at the Hulin and Pleasant Bayou sites until 31 December 1992, at which time both operations were shut down and field sites dismantled. During 1992, the networks recorded seismic signals from earthquakes, sonic booms, geophysical blasting, thunderstorms, etc. However, as in previous years, no local microseismic activity attributable to geopressured-geothermal well testing was recorded.

  7. QEMSCAN° (Quantitative Evaluation of Minerals by Scanning Electron Microscopy): capability and application to fracture characterization in geothermal systems

    NASA Astrophysics Data System (ADS)

    Ayling, B.; Rose, P. E.; Zemach, E.; Drakos, P. S.; Petty, S.

    2011-12-01

    Fractures are important conduits for fluids in geothermal systems, and the creation and maintenance of fracture permeability is a fundamental aspect of EGS (Engineered Geothermal System) development. Hydraulic or chemical stimulation techniques are often employed to achieve this. In the case of chemical stimulation, an understanding of the minerals present in the fractures themselves is desirable to better design a stimulation effort (i.e. which chemical to use and how much). Borehole televiewer surveys provide important information about regional and local stress regimes and fracture characteristics (e.g. fracture aperture), and XRD is useful for examining bulk rock mineralogy, but neither technique is able to quantify the distribution of these minerals in fractures. QEMSCAN° is a fully-automated micro-analysis system that enables quantitative chemical analysis of materials and generation of high-resolution mineral maps and images as well as porosity structure. It uses a scanning electron microscopy platform (SEM) with an electron beam source in combination with four energy-dispersive X-ray spectrometers (EDS). The measured backscattered electron and electron-induced secondary X-ray emission spectra are used to classify sample mineralogy. Initial applications of QEMSCAN° technology were predominantly in the minerals industry and application to geothermal problems has remained limited to date. In this pilot study, the potential application of QEMSCAN° technology to fracture characterization was evaluated using samples of representative mineralized fractures in two geothermal systems (Newberry Volcano, Oregon and Brady's geothermal field, Nevada). QEMSCAN° results were compared with XRD and petrographic techniques. Nine samples were analyzed from each field, collected from the drill core in the 1000-1500 m depth range in two shallow wells (GEO-N2 at Newberry Volcano and BCH-3 at Brady's). The samples were prepared as polished thin sections for QEMSCAN° analysis. Results indicate that a sampling resolution of 10 ?m is sufficient to resolve fracture morphology and mineral zonation (where multiple episodes of mineralization occurred), and enables relatively fast data acquisition (3 cm2 can be analyzed in approximately 3 hours). Finer resolutions (down to 2.5 ?m) take significantly longer, but can be used to provide additional spatial detail in areas of interest after a low resolution (10 ?m) scan. Use of XRD data in conjunction with QEMSCAN° data is sometimes needed to distinguish geothermal alteration minerals with similar chemical compositions (clay minerals, micas and chlorite), however overall the technique appears to have excellent potential for geothermal applications.

  8. Communication Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Sutherland, Barbara, Ed.

    This communication systems guide provides teachers with learning activities for secondary students. Introductory materials include an instructional planning outline and worksheet, an outline of essential elements, a list of objectives, a course description, and a content outline. The guide contains 32 modules on the following topics: story…

  9. Heat-tolerant flowering plants of active geothermal areas in Yellowstone National Park.

    PubMed

    Stout, Richard G; Al-Niemi, Thamir S

    2002-08-01

    A broad survey of most of the major geyser basins within Yellowstone National Park (Wyoming, USA) was conducted to identify the flowering plants which tolerate high rhizosphere temperatures (> or = 40 degrees C) in geothermally heated environments. Under such conditions, five species of monocots and four species of dicots were repeatedly found. The predominant flowering plants in hot soils (>40 degrees C at 2-5 cm depth) were grasses, primarily Dichanthelium lanuginosum. Long-term (weeks to months) rhizosphere temperatures of individual D. lanuginosum above 40 degrees C were recorded at several different locations, both in the summer and winter. The potential role of heat shock proteins (HSPs) in the apparent adaptation of these plants to chronically high rhizosphere temperatures was examined. Antibodies to cytoplasmic class I small heat shock proteins (sHSPs) and to HSP101 were used in Western immunoblot analyses of protein extracts from plants collected from geothermally heated soils. Relatively high levels of proteins reacting with anti-sHSP antibodies were consistently detected in root extracts from plants experiencing rhizosphere temperatures above 40 degrees C, though these proteins were usually not highly expressed in leaf extracts from the same plants. Proteins reacting with antibodies to HSP101 were also present both in leaf and root extracts from plants collected from geothermal soils, but their levels of expression were not as closely related to the degree of heat exposure as those of sHSPs. PMID:12197524

  10. Geothermal Recovery System Using Natural Circulating CO2 as A Heat Transfer Fluid

    NASA Astrophysics Data System (ADS)

    Soma, Hiroshi; Iwasawa, Kenji; Fukumiya, Kenji

    In the conventional system, heat is recovered as sensible heat through liquid anti-freezer circulating in a piping laid underground, but if CO2 is used as a heat transfer fluid, heat is recovered as latent heat which increases the capacity and enables to promote downsize of the equipment and reduction of the electric consumption. It also enables the diameter or the length of heat recovery piping for the same heat exchange performance, thus the installation cost of the piping would be reduced. In our study, a geothermal recovery system using CO2 for air-conditioning was installed, and the heating capacity and the electric consumption were measured. Also, those of a conventional propylene-glycol system were measured. As a result, the CO2-system exerted the same heating ability with the propylene-glycol system with a half length of heat recovery piping and a half electric consumption of the propylene-glycol system. And the reduction in the diameter of the CO2 recovery piping was possible to 50 mm at most to gain more than adequate heating effect.

  11. Candidate radial-inflow turbines and high-density working fluids for geothermal power systems

    Microsoft Academic Search

    Emilie Sauret; Andrew S. Rowlands

    2011-01-01

    Optimisation of Organic Rankine Cycle (ORCs) for binary-cycle geothermal applications could play a major role in determining the competitiveness of low to moderate temperature geothermal resources. Part of this optimisation process is matching cycles to a given resource such that power output can be maximised. Two major and largely interrelated components of the cycle are the working fluid and the

  12. User manual for GEOCITY: A computer model for cost analysis of geothermal district-heating-and-cooling systems. Volume 1: Main text

    NASA Astrophysics Data System (ADS)

    Huber, H. D.; Fassbender, L. L.; Bloomster, C. H.

    1982-09-01

    The cost of residential space heating, space cooling, and sanitary water heating or process heating (cooling) using geothermal energy from a hydrothermal reservoir was calculated. The GEOCITY simulates the complete geothermal heating and cooling system, which consists of two principal parts: the reservoir and fluid transmission system and the distribution system. Geothermal space heating is provided by circulating hot water through radiators, convectors, and fan-coil units. Geothermal process heating is provided by directly using the hot water or by circulating it through a process heat exchanger. The life cycle cost of thermal energy from the reservoir and fluid transmission system to the distribution system and the life cycle cost of heat (chill) to the end users are calculated by discounted cash flow analysis.

  13. Shallow open-loop geothermal systems: simulation of heat transfer in groundwater and experimental tests for improving parameterization

    NASA Astrophysics Data System (ADS)

    Fossoul, F.; Orban, P.; Dassargues, A.; Hydrogeology; Environmental Geology

    2011-12-01

    Innovative and efficient strategies for energy use become a priority, especially in civil engineering. Geothermal open-loop systems (geothermal wells) are not so developed in Belgium contrary to close-loop systems. This is generally due to the lack of relevant dimensioning and impact study that must be foreseen during the planning phases of the building. However, as shallow groundwater is widely available, geothermal wells potential is significant. Using both experimental and numerical tools, our aim is to develop a rigorous methodology to design heating and cooling shallow geothermal wells (pumping/reinjection), with a detailed hydrogeological characterization coupled to feasibility, environmental impact assessment, dimensioning, and system sustainability. Concerning numerical modeling, Groundwater flow and heat transfer is computed using different codes (HydroGeoSphere, MT3DMS and SHEMAT) for a comparative sensitivity analysis on a typical case. Coupling and temperature non linearities of hydro-thermal parameters values are checked accurately. As shown previously, small temperature variations (temperatures ranging from 12 to 25 °C) allow to use conventional solute transport codes for modeling heat transfer in groundwater taking benefits of the similarities between solute transport and heat transfer equations. When numerical codes are used as dimensioning tools for long-term simulations, reliable values for hydro-thermal properties of the aquifer are essential. As very few experimental values are available in the literature, field experiments are needed to determine more accurately the local values in different geological/hydrogeological conditions. Apart from thermal response tests (TRT) usually performed for designing a close-loop system within a borehole considered in static groundwater conditions, there is no standard procedure for geothermal wells systems. In an open-loop system, groundwater movement induced by the pumping is responsible for a major heat transfer by forced convection and cannot be neglected. A pilote site is currently studied for optimizing methods in such low temperature geothermal systems. The field experiments include pumping tests (for hydraulic conductivities to be used for dimensioning tracer and heat tracing tests), solute tracer tests, heat tracing tests. Hot water injection is combined with downstream pumping and intermediate temperature and pressure monitoring piezometers for detection of the heat plume shape. Natural temperature variations, due to air temperature, day/night and interseasonal cycles or induced by the river proximity, are filtered. The test characteristics and first results are detailed showing that the combined use of solute tracer tests and heat tracing tests leads to a better characterization of the local hydro-thermal properties.

  14. Dynamics of hydrothermal seeps from the Salton Sea geothermal system (California, USA) constrained by temperature monitoring and time series analysis

    Microsoft Academic Search

    Henrik Svensen; Øyvind Hammer; Adriano Mazzini; Nathan Onderdonk; Stephane Polteau; Sverre Planke; Yuri Y. Podladchikov

    2009-01-01

    Water-, mud-, gas-, and petroleum-bearing seeps are part of the Salton Sea geothermal system (SSGS) in southern California. Carbon dioxide is the main component behind the seeps in the Davis-Schrimpf seep field (˜20,000 m2). In order to understand the mechanisms driving the system, we have investigated the seep dynamics of the field by monitoring the temperature of two pools and

  15. Dynamics of hydrothermal seeps from the Salton Sea geothermal system (California, USA) constrained by temperature monitoring and time series analysis

    Microsoft Academic Search

    Henrik Svensen; Øyvind Hammer; Adriano Mazzini; Nathan Onderdonk; Stephane Polteau; Sverre Planke; Yuri Y. Podladchikov

    2009-01-01

    Water-, mud-, gas-, and petroleum-bearing seeps are part of the Salton Sea geothermal system (SSGS) in southern California. Carbon dioxide is the main component behind the seeps in the Davis-Schrimpf seep field (?20,000 m2). In order to understand the mechanisms driving the system, we have investigated the seep dynamics of the field by monitoring the temperature of two pools and

  16. Geologic and hydrologic research on the Moana geothermal system, Washoe County, Nevada. Final report October 1, 1982-December 31, 1983

    SciTech Connect

    Flynn, T.; Ghusn, G. Jr.

    1984-01-01

    Combined geologic, geophysical, geochemical, and drilling exploration surveys were used to assess the Moana geothermal resource in Washoe County, Nevada, and to determine its relationship with nearby Steamboat Hot Springs. Moana is the largest single moderate-temperature resource in Nevada that supports geothermal space heating applications. Results show that the general geology and structure for the two systems is similar, but important differences exist with respect to reservoir rocks. Gravity data delineated the contact between important volcanic and sedimentary rocks in Moana, but contour trends did not correlate well with mapped faults. Fluid geochemistry data show major differences in bulk chemical composition, stable-light isotope ratios, and radiocarbon ages for Moana and Steamboat geothermal waters. Water level measurements in observation wells in Moana show simultaneous increasing and decreasing values in different sections of the geothermal area. Temperature-depth profiles changed little during the six-month monitoring period. Direct use of the resource is increasing and longer-lasting, more efficient down-hole heat exchangers are replacing previous equipment that was prone to scaling and corrosion. A computer program that calculates heat output for state-of-the-art heat exchangers is described. Recommendations for continued monitoring, heat exchanger design, and fluid reinjection studies are included. Data are available to government agencies responsible for regulation as well as local residents and potential developers to ensure prudent resource utilization.

  17. Final Report: Natural State Models of The Geysers Geothermal System, Sonoma County, California

    SciTech Connect

    T. H. Brikowski; D. L. Norton; D. D. Blackwell

    2001-12-31

    Final project report of natural state modeling effort for The Geysers geothermal field, California. Initial models examined the liquid-dominated state of the system, based on geologic constraints and calibrated to match observed whole rock delta-O18 isotope alteration. These models demonstrated that the early system was of generally low permeability (around 10{sup -12} m{sup 2}), with good hydraulic connectivity at depth (along the intrusive contact) and an intact caprock. Later effort in the project was directed at development of a two-phase, supercritical flow simulation package (EOS1sc) to accompany the Tough2 flow simulator. Geysers models made using this package show that ''simmering'', or the transient migration of vapor bubbles through the hydrothermal system, is the dominant transition state as the system progresses to vapor-dominated. Such a system is highly variable in space and time, making the rock record more difficult to interpret, since pressure-temperature indicators likely reflect only local, short duration conditions.

  18. Recovery act: development of design and simulation tool for hybrid geothermal heat pump system

    SciTech Connect

    Wang, Shaojie

    2014-05-29

    The ground source heat pump (GSHP) system is one of the most energy efficient HVAC technologies in the current market. However, the heat imbalance may degrade the ability of the ground loop heat exchanger (GLHX) to absorb or reject heat. The hybrid GSHP system, which combines a geothermal well field with a supplemental boiler or cooling tower, can balance the loads imposed on the ground loop heat exchangers to minimize its size while retaining superior energy efficiency. This paper presents a recent simulation-based study with an intention to compare multiple common control strategies used in hybrid GSHP systems, including fixed setpoint, outside air reset, load reset, and wetbulb reset. A small office in Oklahoma City conditioned by a hybrid GSHP system was simulated with the latest version of eQUEST 3.7[1]. The simulation results reveal that the hybrid GSHP system has the excellent capability to meet the cooling and heating setpoints during the occupied hours, balance thermal loads on the ground loop, as well as improve the thermal comfort of the occupants with the undersized well field.

  19. National Geothermal Data System: Open Access to Geoscience Data, Maps, and Documents

    NASA Astrophysics Data System (ADS)

    Caudill, C. M.; Richard, S. M.; Musil, L.; Sonnenschein, A.; Good, J.

    2014-12-01

    The U.S. National Geothermal Data System (NGDS) provides free open access to millions of geoscience data records, publications, maps, and reports via distributed web services to propel geothermal research, development, and production. NGDS is built on the US Geoscience Information Network (USGIN) data integration framework, which is a joint undertaking of the USGS and the Association of American State Geologists (AASG), and is compliant with international standards and protocols. NGDS currently serves geoscience information from 60+ data providers in all 50 states. Free and open source software is used in this federated system where data owners maintain control of their data. This interactive online system makes geoscience data easily discoverable, accessible, and interoperable at no cost to users. The dynamic project site http://geothermaldata.org serves as the information source and gateway to the system, allowing data and applications discovery and availability of the system's data feed. It also provides access to NGDS specifications and the free and open source code base (on GitHub), a map-centric and library style search interface, other software applications utilizing NGDS services, NGDS tutorials (via YouTube and USGIN site), and user-created tools and scripts. The user-friendly map-centric web-based application has been created to support finding, visualizing, mapping, and acquisition of data based on topic, location, time, provider, or key words. Geographic datasets visualized through the map interface also allow users to inspect the details of individual GIS data points (e.g. wells, geologic units, etc.). In addition, the interface provides the information necessary for users to access the GIS data from third party software applications such as GoogleEarth, UDig, and ArcGIS. A redistributable, free and open source software package called GINstack (USGIN software stack) was also created to give data providers a simple way to release data using interoperable and shareable standards, upload data and documents, and expose those data as a node in the NGDS or any larger data system through a CSW endpoint. The easy-to-use interface is supported by back-end software including Postgres, GeoServer, and custom CKAN extensions among others.

  20. Geothermal -- The Energy Under Our Feet: Geothermal Resource Estimates for the United States

    SciTech Connect

    Green, B. D.; Nix, R. G.

    2006-11-01

    On May 16, 2006, the National Renewable Energy Laboratory (NREL) in Golden, Colorado hosted a geothermal resources workshop with experts from the geothermal community. The purpose of the workshop was to re-examine domestic geothermal resource estimates. The participating experts were organized into five working groups based on their primary area of expertise in the following types of geothermal resource or application: (1) Hydrothermal, (2) Deep Geothermal Systems, (3) Direct Use, (4) Geothermal Heat Pumps (GHPs), and (5) Co-Produced and Geopressured. The workshop found that the domestic geothermal resource is very large, with significant benefits.

  1. Colorado geothermal commercialization program: community development of geothermal energy in Pagosa Springs, Colorado

    SciTech Connect

    Coe, B.A.

    1980-01-01

    A district heating system for the Pagosa Springs central business district is in the planning stage. A detailed analysis of the project is presented. It comprises area and site specific studies and describes in detail the recent, current, anticipated, and postulated geothermal development activities. (MHR)

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

    SciTech Connect

    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. In contrast, fluid inclusions trapped prior to injection are relatively gas rich. These results suggest that the rocks undergo extensive microfracturing during injection and that the composition of the fluid inclusions will be biased toward the youngest event. Interactions between the reservoir rocks and injectate were modeled using the non-isothermal reactive geochemical transport code TOUGHREACT. Changes in fluid pH, fracture porosity, fracture permeability, fluid temperature, and mineral abundances were monitored. The simulations predict that amorphous silica will precipitate primarily within a few meters of the injection well and that mineral deposition will lead to rapid declines in fracture porosity and permeability, consistent with field observations. In support of Enhanced Geothermal System development, petrologic studies of Coso well 46A-19RD were conducted to determine the regions that are most likely to fail when stimulated. These studies indicate that the most intensely brecciated and altered rocks in the zone targeted for stimulation (below 10,000 ft (3048 m)) occur between 11,200 and 11,350 ft (3414 and 3459 m). This zone is interpreted as a shear zone that initially juxtaposed quartz diorite against granodiorite. Strong pervasive alteration and veining within the brecciated quartz diorite and granodiorite suggest this shear zone was permeable in the past. This zone of weakness was subsequently exploited by a granophyre dike whose top occurs at 11,350 ft (3459 m). The dike is unaltered. We anticipate, based on analysis of the well samples that failure during stimulation will most likely occur on this shear zone.

  3. Change in the Thermal Process in a Volcanic Geothermal Reservoir Beneath an Active Fumarolic Field After the 1995 Phreatic Eruption of Kuju volcano, Japan

    NASA Astrophysics Data System (ADS)

    Ehara, S.; Fujimitsu, Y.; Nishijima, J.; Fukuoka, K.; Ozawa, M.

    2005-12-01

    Kuju volcano, which is composed of many lava domes, is a typical andesite island arc volcano. The main rock type is hornblend andesite. The volcanic activity started 0.15 Ma and the most recent big pyroclastic eruption occurred 0.05 Ma. Magmatic eruptions occurred at intervals from every 1000 to 2000 years in recent 15 kyrs. The most recent magmatic eruption is about 1700 years ago. Several phreatic eruptions occurred in historic times at intervals ranging from several tens to a hundred years. The fumarolic field in the central part of Kuju volcano is one of the most intense geothermal fields in Japan. The natural heat discharge rate was estimated at about 100 MW before the 1995 phreatic eruption and most of it is from steaming ground and fumaroles. Temperatures of fumaroles generally exceed 200 degrees C and the maximum observed temperature prior to the 1995 phreatic eruption was 508 degrees C. A two-phase volcanic geothermal reservoir beneath the fumarolic field is proposed based on numerical modeling (Ehara, 1992). Kuju volcano began to erupt on 11 October, 1995 from the new craters which are about 300 m south of the pre-existing fumarolic field (first eruption). The volume of ashes discharged by the eruption is about 20000 cubic meters. The subsequent eruption in mid-December produced about 5000 cubic meters ashes (second eruption). After these eruptions, a large amount of steam and heat started to be discharged from the new craters and the pre-existing fumarolic field. Such discharge is still continuing at present (August,2005). The eruption was considered to be a phreatic eruption, because there has been no magmatic activity at the surface. Several kinds of geophysical measurements such as thermal, gravimetric, geomagnetic, seismic, geodetic etc. have been conducted after the 1995 eruption. As a result, quick temperature decrease of the volcanic geothermal reservoir was deduced from repeat thermal and geomagnetic measurements. Repeat gravity measurements showed quick decrease around the new craters after the eruption and then gravity recovered gradually. Such temperature and gravity changes show recharge of a large amount of cold meteoric water to the volcanic geothermal reservoir. The meteoric water recharge was induced by the sudden decrease of pressure in the volcanic geothermal reservoir accompanied by the phreatic eruption. Numerical modeling of the thermal process in the volcanic geothermal reservoir after the phreatic eruption simulates the observed cooling of the volcanic geothermal reservoir very well. Such a process is very similar to the production of geothermal fluids from the geothermal reservoir without reinjection.

  4. Geothermal Energy Technology: a current-awareness bulletin

    SciTech Connect

    Smith, L.B. (ed.)

    1983-01-15

    This bulletin announces on a semimonthly basis the current worldwide information available on the technology required for economic recovery of geothermal energy and its use either directly or for production of electric power. The subject content encompasses: resource status and assessment, geology and hydrology of geothermal systems, geothermal exploration, legal and institutional aspects, economic and final aspects, environmental aspects and waste disposal, by-products, geothermal power plants, geothermal engineering, direct energy utilization, and geothermal data and theory.

  5. Imperial County geothermal development annual meeting: summary

    SciTech Connect

    Not Available

    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)

  6. Investigation of hydrothermal boiling and steam quenching as possible sources of volcanic tremor and geothermal ground noise

    Microsoft Academic Search

    Leet

    1991-01-01

    Volcanic tremor and geothermal ground noise are sustained seismic emissions associated with volcanic and geothermal activity. In this study I investigate whether such signals could be caused by boiling or steam quenching in liquid-dominated zones of subterranean hydrothermal systems. The framework for the study is a conceptual model that assumes: (1) the fundamental source of seismic energy is the growth\\/collapse

  7. BDGEO 4.0: An efficient system for assessment and management of geothermal fields

    SciTech Connect

    Iglesias, E.R.; Torres, R.J.; Garcia, Y. [Instituto de Investigaciones Electricas (Mexico)] [and others

    1997-12-31

    BDGEO 4.0, is our current version of a user-friendly, modular, integrated Windows application for storage, analysis and visualization of geothermal data. Its main goal is to standardize and simplify the assessment and management of geothermal fields at departmental level. BDGEO 4.0 is set up as a distributed application over a local area network. The main components of BDGEO 4.0 are a database and a visualization package. In addition to the usual capabilities of a sophisticated relational database, BDGEO 4.0 offers visualization tools tailored for assessment and management of geothermal fields. Data transfer between these components is seamless and transparent to users.

  8. State-of-the-art hydrogen sulfide control for geothermal energy systems: 1979

    SciTech Connect

    Stephens, F.B.; Hill, J.H.; Phelps, P.L. Jr.

    1980-03-01

    Existing state-of-the-art technologies for removal of hydrogen sulfide are discussed along with a comparative assessment of their efficiencies, reliabilities and costs. Other related topics include the characteristics of vapor-dominated and liquid-dominated resources, energy conversion systems, and the sources of hydrogen sulfide emissions. It is indicated that upstream control technologies are preferred over downsteam technologies primarily because upstream removal of hydrogen sulfide inherently controls all downstream emissions including steam-stacking. Two upstream processes for vapor-dominated resources appear promising; the copper sulfate (EIC) process, and the steam converter (Coury) process combined with an off-gas abatement system such as a Stretford unit. For liquid-dominated systems that produce steam, the process where the non-condensible gases are scrubbed with spent geothermal fluid appears to be promising. An efficient downstream technology is the Stretford process for non-condensible gas removal. In this case, partitioning in the surface condenser will determine the overall abatement efficiency. Recommendations for future environmental control technology programs are included.

  9. Geothermal progress monitor. Progress report No. 7

    SciTech Connect

    Not Available

    1983-04-01

    A state-by-state review of major geothermal-development activities during 1982 is presented. It also inlcudes a summary of recent drilling and exploration efforts and the results of the 1982 leasing program. Two complementary sections feature an update of geothermal direct-use applications and a site-by-site summary of US geothermal electric-power development.

  10. Geology of the Soda Lake geothermal area

    Microsoft Academic Search

    Sibbett

    1979-01-01

    The Soda Lake geothermal area is located in the Carson Desert, west-central Nevada. Hot springs activity has occurred in the Soda Lake area in the past, resulting in surface deposits which have motivated present geothermal exploration. The geothermal anomaly is in Quaternary clastic sediments which are as much as 4600 feet thick. The sediments consist of interbedded deltaic, lacustrine, and

  11. Development of a 3D hydrogeological and geomechanical model of an Enhanced Geothermal System using micro-earthquake and ground deformation data from a 1-year injection program

    NASA Astrophysics Data System (ADS)

    Jeanne, P.; Rutqvist, J.; Vasco, D. W.; Garcia, J.; Dobson, P. F.; Walter, M.; Hartline, C. S.; Borgia, A.

    2013-12-01

    In this study, integrated coupled processes modeling and field observations are used to build a three-dimensional hydrogeological and geomechanical model of an enhanced geothermal system (EGS) at the northwestern part of The Geysers geothermal field, California. We constructed a model and characterized hydraulic and mechanical properties of relevant geological layers and a system of multiple intersecting fault zones. The characterization was conducted through detailed coupled modeling of a 1 year stimulation injection with simultaneous field monitoring of reservoir pressure, microseismic activity, and ground surface deformations. The structural reservoir properties were characterized through a dynamic analysis of the microseismic activity recorded during the injection. The analysis of ground surface deformations were found to be particularly challenging as the subtle ground surface deformations caused by the injection at >3 km depth are intermingled with deformations caused by both tectonic deformations and seasonal ground surface effects associated with rainfall. However, through a detailed analysis of the field data we isolated local surface deformations associated with injection. Using the coupled fluid flow and geomechanical analysis of reservoir pressure responses in a number of monitoring wells and microseismic activity around the injection well, we back-calculated the hydraulic and mechanical properties of relevant rock mass layers and faults. The results show (1) the main cause of induced seismicity is an injection related pressure increase sufficient to trigger detectable seismic events, (2) the extension and shape of the microseismic cloud is strongly influenced by the pre-existing tectonic structures, (3) the critical importance of considering the fault system, including faults that compartmentalize the EGS system, and more permeable faults that provide conduits for injection water and fluid pressure diffusion that can extend up to one kilometer from the injection well and deep down into a granitic intrusion at a depth of approximately 4.0 km.

  12. Irrigation pumping using geothermal energy

    Microsoft Academic Search

    D. H. White; L. A. Goldstone

    1982-01-01

    The potential of using geothermal energy in an isobutane binary system to drive directly a cluster of irrigation pumps was evaluated. This three well geothermal system, based at 1500 C (3020 F) resource at 2000 m (6560 ft), would cost an estimated $7,800,000 in capital investment to provide 6000 gpm of irrigation water from 12 water wells. It would serve

  13. Carbon and sulfur isotopes as tracers of fluid-fluid and fluid-rock interaction in geothermal systems

    NASA Astrophysics Data System (ADS)

    Stefansson, A.; Keller, N. S.; Gunnarsson Robin, J.; Kjartansdottir, R.; Ono, S.; Sveinbjörnsdottir, A. E.

    2014-12-01

    Carbon and sulfur are among major components in geothermal systems. They are found in various oxidation state and present in solid phases and fluids (water and vapor). In order to study the reactions and mass movement within multiphase geothermal systems, we have combined geochemical fluid-fluid and fluid-rock modelling with sulfur and carbon isotope fractionation modelling and compared the results with measured carbon and sulfur isotopes in geothermal fluids (water and vapor) for selected low- and high-enthalpy geothermal systems in Iceland. In this study we have focused on ?34S for H2S in vapor and water and SO4 in water as well as ?13C for CO2 in vapor and water phases. Isotope fractionations for CO2 and H2S between vapor and liquid water, upon aqueous speciation and upon carbonate and sulfide mineral formation were revised. These were combined with reaction modelling involving closed system boiling and progressive water-rock interaction to constrain the mass movement and isotope abundance between various phases. The results indicate that for a closed system, carbon and sulfur isotope abundance is largely dependent on progressive fluid-fluid and fluid-rock interaction and the initial total ?34S and ?13C value of the system. Initially, upon progressive fluid rock interaction the ?34S and ?13C values for the bulk aqueous phase approach that of the host rocks. Secondary mineral formation may alter these values, the exact isotope value of the mineral and resulting aqueous phase depending on aqueous speciation and isotope fractionation factor. In turn, aqueous speciation and mineral saturation depends on progressive fluid-rock interaction, fluid-fluid interaction, temperature and acid supply to the system. Depressurization boiling also results in isotope fractionation, the exact isotope value of the vapor and aqueous phase depending on aqueous speciation and isotope fractionation fractor. In this way, carbon and sulfur isotopes may be used combined with measured values for natural fluids to constrain mass movement upon fluid-fluid and fluid-rock interaction in geothermal systems.

  14. Sedimentation plan to assess the impact of geothermal activities to the aquatic ecosystem in the Geyers Calistoga KGRA

    SciTech Connect

    Ireland, R.R.

    1981-05-19

    The prevention of sedimentation or siltation in aquatic ecosystems is always a key environmental issue in the development and operation of power plant units. This report describes a field program which will assess the amount of sedimentation in the streams and tributaties of the Geysers-Calistoga Known Geothermal Resource Area (KGRA) due to development-related or other site-specific activities. This sediment plan is one part of a four part venture - the others are water quality, benthic invertebrates and fisheries studies - initiated by the California Energy Commission and involving numerous California organizations. Included in this report are the cost breakdowns for each phase, maps and rationale of the sampling sites, the methodology for the laboratory sample processing, and examples of the type of graphic and tabular output expected.

  15. LAPA: a composite indicator for prioritization of geothermal-leasing activities on federal lands in the United States

    SciTech Connect

    Yen, W.W.S.; Carbonaro, G.A.; Benson, W.H.

    1982-02-01

    Three factors, incorporating seven quantitative indicators, have been selected to represent criteria for prioritization of geothermal areas. These indicators reflect important dimensions for monitoring and estimating the contributions of particular areas to energy production goals on federal lands. Using computerized graphics and data analysis software, weighting of these indicators by experts is integrated to produce a composite indicator for evaluation of leasing activities. The selection of specific indicators for areas which have a high unleased energy potential, where the response of the private sector is positive, and where the potential delay from environmental factors is minimal is described. The development of the composite LAPA indicator and the application of fuzzy set operations for incorporation of expert judgments about the leasing process are also discussed.

  16. ENERGY FROM THE WEST: ENERGY RESOURCE DEVELOPMENT SYSTEMS REPORT. VOLUME VI: GEOTHERMAL

    EPA Science Inventory

    This report describes the technologies likely to be used for development of geothermal resources in eight western states (Arizona, Colorado, Montana, New Mexico, North Dakota, South Dakota, Utah, and Wyoming). It provides information on input materials and labor requirements, out...

  17. Behavior of Rare Earth Element In Geothermal Systems; A New Exploration/Exploitation Tool

    SciTech Connect

    Scott A. Wood

    2002-01-28

    The goal of this four-year project was to provide a database by which to judge the utility of the rare earth elements (REE) in the exploration for and exploitation of geothermal fields in the United States. Geothermal fluids from hot springs and wells have been sampled from a number of locations, including: (1) the North Island of New Zealand (1 set of samples); (2) the Cascades of Oregon; (3) the Harney, Alvord Desert and Owyhee geothermal areas of Oregon; (4) the Dixie Valley and Beowawe fields in Nevada; (5) Palinpion, the Philippines: (6) the Salton Sea and Heber geothermal fields of southern California; and (7) the Dieng field in Central Java, Indonesia. We have analyzed the samples from all fields for REE except the last two.

  18. Federal Geothermal Research Program Update - Fiscal Year 2001

    SciTech Connect

    Laney, P.T.

    2002-08-31

    This Federal Geothermal Program Research Update reviews the specific objectives, status, and accomplishments of DOE's Geothermal Program for Federal Fiscal Year (FY) 2001. The information contained in this Research Update illustrates how the mission and goals of the Office of Geothermal Technologies are reflected in each R&D activity. The Geothermal Program, from its guiding principles to the most detailed research activities, is focused on expanding the use of geothermal energy.

  19. On the production behavior of enhanced geothermal systems with CO2as working fluid

    SciTech Connect

    Pruess, K.

    2007-05-31

    Numerical simulation is used to evaluate mass flow and heatextraction rates from enhanced geothermal injection-production systemsthat are operated using either CO2 or water as heat transmission fluid.For a model system patterned after the European hot dry rock experimentat Soultz, we find significantly greater heat extraction rates for CO2 ascompared to water. The strong dependence of CO2 mobility (=density/viscosity) upon temperature and pressure may lead to unusualproduction behavior, where heat extraction rates can actually increasefor a time, even as the reservoir is subject to thermal depletion. Wepresent the first-ever three-dimensional simulations of CO2injection-production systems. These show strong effects of gravity onmass flow and heat extraction, due to the large contrast of CO2 densitybetween cold injection and hot production conditions. The tendency forpreferential flow of cold, dense CO2 along the reservoir bottom can leadto premature thermal breakthrough. The problem can be avoided byproducing from only a limited depth interval at the top of thereservoir.

  20. Determination of TDS in Geothermal Systems by Well-Log Analysis

    Microsoft Academic Search

    Susan L. Brown; Brian D. Gobran; Subir K. Sanyal

    1980-01-01

    An estimate of t h e chemistry of the fluid within a geothermal;\\u000areservoir is required to establish the geological source and the;\\u000apossible environmental impact of the fluid as well as scaling and;\\u000acorrosion problems which might develop during production. While a;\\u000adetailed analysis of the chemical composition of a geothermal fluid;\\u000acan only be obtained from a water

  1. Geothermal hydrogen sulfide removal

    SciTech Connect

    Urban, P.

    1981-04-01

    UOP Sulfox technology successfully removed 500 ppM hydrogen sulfide from simulated mixed phase geothermal waters. The Sulfox process involves air oxidation of hydrogen sulfide using a fixed catalyst bed. The catalyst activity remained stable throughout the life of the program. The product stream composition was selected by controlling pH; low pH favored elemental sulfur, while high pH favored water soluble sulfate and thiosulfate. Operation with liquid water present assured full catalytic activity. Dissolved salts reduced catalyst activity somewhat. Application of Sulfox technology to geothermal waters resulted in a straightforward process. There were no requirements for auxiliary processes such as a chemical plant. Application of the process to various types of geothermal waters is discussed and plans for a field test pilot plant and a schedule for commercialization are outlined.

  2. An Integrated Model to Compare Net Electricity Generation for Carbon Dioxide- and Water-Based Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Agarwal, Vikas

    Utilization of supercritical CO2 as a geothermal fluid instead of water has been proposed by Brown in 2000 and its advantages have been discussed by him and other researchers such as Karsten Pruess and Fouillac. This work assesses the net electricity that could be generated by using supercritical CO2 as a geothermal working fluid and compares it with water under the same temperature and pressure reservoir conditions. This procedure provides a method of direct comparison of water and CO2 as geothermal working fluids, in terms of net electricity generation over time given a constant geothermal fluid flow rate. An integrated three-part model has been developed to determine net electricity generation for CO2- and water-based geothermal reservoirs. This model consists of a wellbore model, reservoir simulation, and surface plant simulation. To determine the bottomhole pressure and temperature of the geothermal fluid (either water or CO2) in the injection well, a wellbore model was developed using fluid-phase, thermodynamic equations of state, fluid dynamics, and heat transfer models. A computer program was developed that solves for the temperature and pressure of the working fluid (either water or CO 2) down the wellbore by simultaneously solving for the fluid thermophysical properties, heat transfer, and frictional losses. For the reservoir simulation, TOUGH2, a general purpose numerical simulator has been used to model the temperature and pressure characteristics of the working fluid in the reservoir. The EOS1 module of TOUGH2 has been used for the water system and the EOS2 module of the TOUGH2 code has been employed for the CO2 case. The surface plant is simulated using CHEMCAD, a chemical process simulator, to determine the net electricity generated. A binary organic (iso-pentane) Rankine cycle is simulated. The calculated net electricity generated for the optimized water and CO2 systems are compared over the working time of the reservoir. Based on the theoretical calculations in this work and other specifications assumed, water is found to produce nearly 50-60% more cumulative net electricity in initial 10 years of electricity generation than CO2 (depending on the flow rates; 50% corresponds to 40 kg/s and 60% corresponds to 120 kg/s) keeping all other parameters exactly same. This number goes down to 25-35% more after 30 years of continuous power generation.

  3. Geothermal Injection Technology Program: Annual progress report, Fiscal Year 1986

    SciTech Connect

    Not Available

    1987-07-01

    This report summarizes the Geothermal Injection Technology Program major activities in fiscal year 1986. The Idaho Engineering Laboratory (INEL) and the University of Utah Research Institute (UURI) have been conducting injection research and testing for this program, which was initiated in 1983. Activities at the INEL, representative element nodeling of fracture systems based on stochastic analysis, dual permeability modeling of flow in a fractured geothermal reservoir, and dual permeability model - laboratory and FRACSL-validation studies, are presented first, followed by the University of Utah Research Institute tracer development - experimental studies, which includes a brief description of activities planned for FY-1987.

  4. Geothermal industry assessment

    SciTech Connect

    Not Available

    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)

  5. Influence of faults on the thermal field and fluid system in a geothermal site (Groß Schönebeck, NE-German Basin)

    NASA Astrophysics Data System (ADS)

    Cherubini, Y.; Cacace, M.; Scheck-Wenderoth, M.; Moeck, I.

    2012-04-01

    Faults disturb the conformal succession of geological layers, and therefore they might act as pathways or barriers to fluid flow. To make use of geothermal energy reserves, it is important to understand the physical processes controlling heat transfer and fluid motion and the impact of faults in the subsurface. Numerical simulations represent a useful and increasingly common tool for geothermal exploration and reservoir engineering as they consider both, the structural setting of the subsurface and the physical processes of the coupled fluid and heat transport. For our coupled fluid and heat transport simulations, we improved an existing 3D structural model of the geothermal site Groß Schönebeck (Moeck et al. 2005), located in the North East German Basin. The coupled non-linear partial differential equations describing fluid flow and heat transport in a saturated porous medium are numerically solved by the finite element software FEFLOW® (Diersch, 2002). Simulation results are validated with borehole data. The geological model covering an area of 55 x 50 km resolves a succession of Carboniferous to Quaternary age and reaches down to 5 km depth. An up to 1200 m thick Upper Permian (Zechstein) salt layer decouples two fault systems. We focus on the subsalt fault system which comprises the reservoir target zone. There, major NW-SE trending faults intersect with minor NE-SW oriented faults. These faults are integrated as vertical discrete elements within the numerical model. By discrimination of critically stressed and extensional faults within the current stress field, the hydraulic conductivity of the faults is assessed (Moeck et al. 2009). We investigate the influence of faults on the fluid system and thermal field by comparing the results from models that do not integrate faults with fault models. We find that faults may have a local, strong impact on the hydrothermal field. As such, the results provide essential information on the fluid motion and temperature variations and can support geothermal exploration.

  6. Design and development of a greenhouse growing system with a cooling facility using geothermal energy; Part 1

    SciTech Connect

    Tanaka, Shunichiro; Ishibashi, Sadato (Kagoshima Univ. (Japan). Faculty of Agriculture); Kaieda, Masami (Kagoshima Prefectural Federation of Fisheries Cooperative Associations (Japan))

    1994-03-01

    The purpose of the present work was to develop a greenhouse growing system with a night cooling facility using geothermal energy to grow fall and winter vegetables during high summer temperatures. In this paper, the authors first designed and constructed a greenhouse cooling facility using geothermal water for the driving energy, and then conducted a cooling performance test and growth experiment in the growing of vegetables. As a result of the investigation, first, the facility showed the cooling performance as designed, since the air in the greenhouse was cooled to the desired temperature of 15 C. Second, in the open division, almost all the spinach, lettuce, and Kinusaya peas died back during growing and there was therefore no yield. However, in the cooling division, all the vegetables grew normally and their yields were large. From the results mentioned above, the authors concluded that it is possible to grow vegetables during the high-temperature summer season in greenhouse cooled only at night.

  7. Structure of a low-enthalpy geothermal system inferred from magnetotellurics - A case study from Sri Lanka

    NASA Astrophysics Data System (ADS)

    Nimalsiri, Thusitha Bandara; Suriyaarachchi, Nuwan Buddhika; Hobbs, Bruce; Manzella, Adele; Fonseka, Morrel; Dharmagunawardena, H. A.; Subasinghe, Nalaka Deepal

    2015-06-01

    First comprehensive geothermal exploration in Sri Lanka was conducted in 2010 encompassing seven thermal springs, of which Kapurella records the highest temperature. The study consisted of passive magnetotelluric (MT) soundings, in which static shifts were corrected using time domain electromagnetic method (TDEM). A frequency range of 12,500-0.001 Hz was used for MT acquisition and polar diagrams were employed for dimensionality determination. MT and TDEM data were jointly inverted and 2D models were created using both transverse electric and transverse magnetic modes. A conductive southeast dipping structure is revealed from both phase pseudosections and the preferred 2D inversion model. A conductive formation starting at a depth of 7.5 km shows a direct link with the dipping structure. We suggest that these conductive structures are accounted for deep circulation and accumulation of groundwater. Our results show the geothermal reservoir of Kapurella system with a lateral extension of around 2.5 km and a depth range of 3 km. It is further found that the associated dolerite dike is not the source of heat although it could be acting as an impermeable barrier to form the reservoir. The results have indicated the location of the deep reservoir and the possible fluid path of the Kapurella system, which could be utilized to direct future geothermal studies. This pioneering study makes suggestions to improve future MT data acquisition and to use boreholes and other geophysical methods to improve the investigation of structures at depth.

  8. Update on subsidence at the Wairakei-Tauhara geothermal system, New Zealand

    USGS Publications Warehouse

    Allis, R.; Bromley, C.; Currie, S.

    2009-01-01

    The total subsidence at the Wairakei field as a result of 50 years of geothermal fluid extraction is 15 ?? 0.5 m. Subsidence rates in the center of the subsidence bowl have decreased from over 450 mm/year during the 1970s to 80-90 mm/year during 2000-2007. The location of the bowl, adjacent to the original liquid outflow zone of the field, has not changed significantly. Subsidence at the Tauhara field due to Wairakei production was not as well documented in the early years but appeared later and has been less intense than at Wairakei. Total subsidence of 2.6 ?? 0.5 m has also occurred close to the original liquid outflow zone of this field, and maximum subsidence rates in this area today are in the 80-100 mm/year range. In the western part of the Wairakei field, near the area of hot upflow, subsidence rates have approximately doubled during the last 20 years to 30-50 mm/year. This increase appears to be have been caused by declining pressure in the underlying steam zone in this area, which is tapped by some production wells. At Tauhara field, two areas of subsidence have developed since the 1990s with rates of 50-65 mm/year. Although less well-determined, this subsidence may also be caused by declining pressure in shallow steam zones. The cause of the main subsidence bowls in the Wairakei-Tauhara geothermal system is locally high-compressibility rocks within the Huka Falls Formation (HFF), which are predominantly lake sediments and an intervening layer of pumice breccia. At Wairakei, casing deformation suggests the greatest compaction is at 150-200 m depth. The cause of the large compressibility is inferred to be higher clay content in the HFF due to intense hydrothermal alteration close to the natural fluid discharge areas. Future subsidence is predicted to add an additional 2-4 m to the Wairakei bowl, and 1-2 m elsewhere, but these estimates depend on the assumed production-injection scenarios.

  9. Geothermal Energy

    SciTech Connect

    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. Thermal modeling of the Clear Lake magmatic system, California: Implications for conventional and hot dry rock geothermal development

    SciTech Connect

    Stimac, J.; Goff, F.; Wohletz, K.

    1997-06-01

    The combination of recent volcanism, high heat flow ({ge} HFU or 167 mW/m{sup 2}), and high conductive geothermal gradient (up to 120{degree} C/km) makes the Clear Lake region of northern California one of the best prospects for hot dry rock (HDR) geothermal development in the US. The lack of permeability in exploration wells and lack of evidence for widespread geothermal reservoirs north of the Collayomi fault zone are not reassuring indications for conventional geothermal development. This report summarizes results of thermal modeling of the Clear Lake magmatic system, and discusses implications for HDR site selection in the region. The thermal models incorporate a wide range of constraints including the distribution and nature of volcanism in time and space, water and gas geochemistry, well data, and geophysical surveys. The nature of upper crustal magma bodies at Clear Lake is inferred from studying sequences of related silicic lavas, which tell a story of multistage mixing of silicic and mafic magma in clusters of small upper crustal chambers. Thermobarometry on metamorphic xenoliths yield temperature and pressure estimates of {approximately}780--900 C and 4--6 kb respectively, indicating that at least a portion of the deep magma system resided at depths from 14 to 21 km (9 to 12 mi). The results of thermal modeling support previous assessments of the high HDR potential of the area, and suggest the possibility that granitic bodies similar to The Geysers felsite may underlie much of the Clear Lake region at depths as little as 3--6 km. This is significant because future HDR reservoirs could potentially be sited in relatively shallow granitoid plutons rather than in structurally complex Franciscan basement rocks.

  11. Geopressured geothermal bibliography (Geopressure Thesaurus)

    SciTech Connect

    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. Chemical interaction of aqueous solutions with epidote-feldspar mineral assemblages in geologic systems. II. Equilibrium constraints in metamorphic/geothermal processes

    SciTech Connect

    Bird, D.K.; Helgeson, H.C.

    1981-05-01

    Thermodynamic analysis of the system Na/sub 2/O-K/sub 2/O-CaO-FeO-Fe/sub 2/O/sub 3/-Al/sub 2/O/sub 3/-SiO/sub 2/-H/sub 2/O-HCl-CO/sub 2/ at pressures and temperatures to 5 kb and 600/sup 0/C affords quantitative description and interpretation of phase relations among epidote, garnet, plagioclase, and alkali feldspar solid solutions in hydrothermal systems. Comparison of computed and observed compositions of these minerals and coexisting fluids suggests that the calculations afford close approximation of equilibrium and mass transfer in metamorphic/geothermal processes. The standard molal enthalpies of decomposition reactions for plagioclase are of the order of -4 to -50 kcal mole/sup -1/, which requires the activity of the anorthite component of plagioclase coexisting with epidote solid solutions to increase with increasing temperature at constant pressure. In contrast, because the standard molal volumes of these reactions are also negative, a/sub CaAl/sub 2/Si/sub 2/O/sub 8// decreases with increasing pressure at constant temperature. Either stoichiometric epidote or clinozoisite is compatible with plagioclase, quartz, calcite, and an aqueous phase, but only at X/sub CO/sub 2// less than or equal to 0.2. The complex zoning commonly exhibited by both plagioclase and epidote solid solutions in geologic systems can be attributed to minor isothermal/isobaric changes in the composition of coexisting aqueous solutions. Logarithmic activity and fugacity diagrams constructed with provision for solid solution permit documentation of such changes and facilitate thermodynamic interpretation of mineral and fluid compositions in metamorphic/geothermal systems.

  13. What can granular media teach us about deformation in geothermal systems

    SciTech Connect

    Stephen L. Karner

    2004-06-01

    Experiments on granular media have significantly improved our understanding of deformation processes in porous rocks. Laboratory results have lead to fundamental theoretical developments (such as poroelasticity, or rate and state-variable friction) that have found widespread application. This paper presents results from laboratory experiments that help constrain these theories. Data from triaxial deformation experiments on quartz sand aggregates are used to illustrate stress-dependent behavior of poroelastic parameters (e.g. the Biot-Willis and Skempton coefficients). Calculations for these coefficients show systematic variations as effective stress increases, in a manner consistent with measured compressibilities of the aggregate. Data from shear experiments show that frictional strength varies systematically with time and temperature. At temperatures below 450 oC, shear zones exhibit greater cohesive strengths as the time of stationary contact increases (hence, positive healing rates). For conditions exceeding 450 oC, shear zone strength is seen to decrease with contact time (negative healing rates). The results from both volumetric compaction and frictional shear experiments are well described by poroelasticity as well as rate and state-variable friction. The combination of these constitutive relations may provide a powerful tool that can be used in numerical models that couple thermal, mechanical, hydraulic, and temporal processes – as occur in geothermal systems.

  14. Numerical studies of cold water injection into vapor-dominated geothermal systems

    SciTech Connect

    Lai, C.H; Bodvarsson, G.S.

    1991-01-01

    Recent reservoir pressure and steam flow rate declines at The Geysers geothermal field in California have attracted interest in studies of increased cold water injection into this system. In this paper, numerical studies of such injection into a fractured vapor-dominated reservoir are conducted using a two-dimensional radial, double-porosity model. The results obtained indicate that cold water injection into superheated (low-pressure) zones will greatly enhance the productivities of steam wells. Injection into two-phase zones with significant liquid reserves in the matrix blocks does not appear to aid in steam recovery until most of the original liquid reserves are depleted. Sensitivity studies are conducted over the range of fracture and matrix permeabilities applicable to the Geysers. The sensitivity of the grid size is also conducted, and shows very large grid effects. A fine vertical space discretization near the bottom of the reservoir is necessary to accurately predict the boiling of the injected water. 28 refs., 15 figs., 3 tabs.

  15. Temporal changes in noble gas compositions within the Aidlinsector ofThe Geysers geothermal system

    SciTech Connect

    Dobson, Patrick; Sonnenthal, Eric; Kennedy, Mack; van Soest,Thijs; Lewicki, Jennifer

    2006-05-03

    The use of nonreactive isotopic tracers coupled to a full thermal-hydrological reservoir simulation allows for an improved method of investigating how reservoir fluids contained within matrix and fractures contribute over time to fluids produced from geothermal systems. A combined field and modeling study has been initiated to evaluate the effects of injection, production, and fracture-matrix interaction on produced noble gas contents and isotopic ratios. Gas samples collected periodically from the Aidlin steam field at The Geysers, California, between 1997 and 2006 have been analyzed for their noble gas compositions, and reveal systematic shifts in abundance and isotopic ratios over time. Because of the low concentrations of helium dissolved in the injection waters, the injectate itself has little impact on the helium isotopic composition of the reservoir fluids over time. However, the injection process may lead to fracturing of reservoir rocks and an increase in diffusion-controlled variations in noble gas compositions, related to gases derived from fluids within the rock matrix.

  16. Life Cycle Water Consumption and Water Resource Assessment for Utility-Scale Geothermal Systems: An In-Depth Analysis of Historical and Forthcoming EGS Projects

    SciTech Connect

    Clark, Corrie E. [Environmental Science Division] [Environmental Science Division; Harto, Christopher B. [Environmental Science Division] [Environmental Science Division; Schroeder, Jenna N. [Environmental Science Division] [Environmental Science Division; Martino, Louis E. [Environmental Science Division] [Environmental Science Division; Horner, Robert M. [Environmental Science Division] [Environmental Science Division

    2013-11-05

    This report is the third in a series of reports sponsored by the U.S. Department of Energy Geothermal Technologies Program in which a range of water-related issues surrounding geothermal power production are evaluated. The first report made an initial attempt at quantifying the life cycle fresh water requirements of geothermal power-generating systems and explored operational and environmental concerns related to the geochemical composition of geothermal fluids. The initial analysis of life cycle fresh water consumption of geothermal power-generating systems identified that operational water requirements consumed the vast majority of water across the life cycle. However, it relied upon limited operational water consumption data and did not account for belowground operational losses for enhanced geothermal systems (EGSs). A second report presented an initial assessment of fresh water demand for future growth in utility-scale geothermal power generation. The current analysis builds upon this work to improve life cycle fresh water consumption estimates and incorporates regional water availability into the resource assessment to improve the identification of areas where future growth in geothermal electricity generation may encounter water challenges. This report is divided into nine chapters. Chapter 1 gives the background of the project and its purpose, which is to assess the water consumption of geothermal technologies and identify areas where water availability may present a challenge to utility-scale geothermal development. Water consumption refers to the water that is withdrawn from a resource such as a river, lake, or nongeothermal aquifer that is not returned to that resource. The geothermal electricity generation technologies evaluated in this study include conventional hydrothermal flash and binary systems, as well as EGSs that rely on engineering a productive reservoir where heat exists, but where water availability or permeability may be limited. Chapter 2 describes the approach and methods for this work and identifies the four power plant scenarios evaluated: a 20-MW EGS binary plant, a 50-MW EGS binary plant, a 10-MW hydrothermal binary plant, and a 50-MW hydrothermal flash plant. The methods focus on (1) the collection of data to improve estimation of EGS stimulation volumes, aboveground operational consumption for all geothermal technologies, and belowground operational consumption for EGS; and (2) the mapping of the geothermal and water resources of the western United States to assist in the identification of potential water challenges to geothermal growth. Chapters 3 and 4 present the water requirements for the power plant life cycle. Chapter 3 presents the results of the current data collection effort, and Chapter 4 presents the normalized volume of fresh water consumed at each life cycle stage per lifetime energy output for the power plant scenarios evaluated. Over the life cycle of a geothermal power plant, from construction through 30 years of operation, the majority of water is consumed by plant operations. For the EGS binary scenarios, where dry cooling was assumed, belowground operational water loss is the greatest contributor depending upon the physical and operational conditions of the reservoir. Total life cycle water consumption requirements for air-cooled EGS binary scenarios vary between 0.22 and 1.85 gal/kWh, depending upon the extent of belowground operational water consumption. The air-cooled hydrothermal binary and flash plants experience far less fresh water consumption over the life cycle, at 0.04 gal/kWh. Fresh water requirements associated with air- cooled binary operations are primarily from aboveground water needs, including dust control, maintenance, and domestic use. Although wet-cooled hydrothermal flash systems require water for cooling, these plants generally rely upon the geofluid, fluid from the geothermal reservoir, which typically has high salinity and total dissolved solids concentration and is much warmer than normal groundwater sources, for their cooling water needs; thus,

  17. Geothermal mineralized scales in the pipe system of the geothermal Piancastagnaio power plant (Mt. Amiata geothermal area): a key to understand the stibnite, cinnabarite and gold mineralization of Tuscany (central Italy)

    Microsoft Academic Search

    Giulio Morteani; Giovanni Ruggieri; Peter Möller; Christine Preinfalk

    2011-01-01

    The CO2-rich geothermal fluids produced in the Piancastagnaio geothermal field (Mt. Amiata geothermal area, Southern Tuscany, Italy)\\u000a show temperatures up to 360°C and pressures of about 200 bar at depths of around 3,500 m (Giolito, Ph.D. thesis, Università\\u000a degli Studi di Firenze, Italy, pp 1–147, 2005). CaCO3- and\\/or SiO2-dominated scales are deposited in the pipes leading to the pressure and atmospheric separators

  18. Marine and land active-source seismic investigation of geothermal potential, tectonic structure, and earthquake hazards in Pyramid Lake, Nevada

    NASA Astrophysics Data System (ADS)

    Eisses, A.; Kell, A. M.; Kent, G.; Driscoll, N. W.; Karlin, R. E.; Baskin, R. L.; Louie, J. N.; Smith, K. D.; Pullammanappallil, S.

    2011-12-01

    Preliminary slip rates measured across the East Pyramid Lake fault, or the Lake Range fault, help provide new estimates of extension across the Pyramid Lake basin. Multiple stratigraphic horizons spanning 48 ka were tracked throughout the lake, with layer offsets measured across all significant faults in the basin. A chronstratigraphic framework acquired from four sediment cores allows slip rates of the Lake Range and other faults to be calculated accurately. This region of the northern Walker Lake, strategically placed between the right-lateral strike-slip faults of Honey and Eagle Lakes to the north, and the normal fault bounded basins to the southwest (e.g., Tahoe, Carson), is critical in understanding the underlying structural complexity that is not only necessary for geothermal exploration, but also earthquake hazard assessment due to the proximity of the Reno-Sparks metropolitan area. In addition, our seismic CHIRP imaging with submeter resolution allows the construction of the first fault map of Pyramid Lake. The Lake Range fault can be obviously traced west of Anahoe Island extending north along the east end of the lake in numerous CHIRP lines. Initial drafts of the fault map reveal active transtension through a series of numerous, small, northwest striking, oblique-slip faults in the north end of the lake. A previously field mapped northwest striking fault near Sutcliff can be extended into the west end of Pyramid Lake. This fault map, along with the calculated slip rate of the Lake Range, and potentially multiple other faults, gives a clearer picture into understanding the geothermal potential, tectonic regime and earthquake hazards in the Pyramid Lake basin and the northern Walker Lane. These new results have also been merged with seismicity maps, along with focal mechanisms for the larger events to begin to extend our fault map in depth.

  19. Geothermal Program Review X: proceedings. Geothermal Energy and the Utility Market -- the Opportunities and Challenges for Expanding Geothermal Energy in a Competitive Supply Market

    SciTech Connect

    Not Available

    1992-01-01

    Each year the Geothermal Division of the US Department of Energy conducts an in-depth review of its entire geothermal R&D program. The conference serves several purposes: a status report on current R&D activities, an assessment of progress and problems, a review of management issues, and a technology transfer opportunity between DOE and the US geothermal city. This year`s conference, Program Review X, was held in San Francisco on March 24--26, 1992. The theme of the review, ``Geothermal Energy and the Utility Market -- The Opportunities and Challenges for Expanding Geothermal Energy in a Competitive Supply Market,`` focused on the needs of the electric utility sector. Geothermal energy, with its power capacity potential of 10 GWe by the year 2010, can provide reliable, enviromentally clean electricity which can help offset the projected increase in demand. Program Review X consisted of seven sessions including an opening session with presentations by Mr. Vikram Budhraja, Vice President of System Planning and Operations, Southern California Edison Company, and Mr. Richard Jaros, President and Chief Operating Officer, California Energy Company. The six technical sessions included presentations by the relevant field researchers covering DOE-sponsored R&D in hydrothermal, hot dry rock, and geopressured energy. Individual projects are processed separately for the data bases.

  20. Sequential emplacement of sheeted plutons and sill-dyke complexes: implication on crustal anatexis and lifespan of hydrothermal/geothermal systems

    NASA Astrophysics Data System (ADS)

    Dini, A.

    2014-12-01

    Depending on initial melt composition, magma volumes, transfer rates, depth of emplacement and tectonic conditions, granite magmas can follow different crystallization paths leading to complex patterns of magmatic fluid/heat release and water-rock interaction in the host rocks at the emplacement level. In the case of multi-pulse magmatic complexes, several contact metamorphic and hydrothermal effects can overlap through time on a relatively small crustal portion. The net result of the described complex evolution is a magmatic system, where magmatic fluid exsolution, heat flow and triggering of meteoric fluid convection cells follow cyclically transient patterns with strong implication on ore forming processes and geothermal field lifespan. Detailed field mapping, coupled with petrographic-geochronologic-geochemical-isotopic data on Late Miocene-Pleistocene granite intrusions in Tuscany provided new insights on melting processes occurred in the roots as well as on paleo-hydrothermal circuits triggered at the roof of the intrusive complexes. Tuscan granite intrusions were constructed incrementally by amalgamation (sheeted plutons) and/or multilayer dispersion (sills and laccoliths) of different magma pulses, sequentially produced as the Apennine fold belt was progressively thinned, heated and intruded by mafic magmas. Partial melting was probably triggered by multiple, small-sized mafic intrusions, that allowed temporary overstepping of dehydration melting reactions into the already pre-heated crust. Dilution in time of the magmatic activity prevented melt homogenization at depth, allowing the formation at the emplacement level of multiple, isotopically distinct, intrusive sheets instead of a single, homogeneous, hybrid pluton. This could be also one of the major key factors explaining the prolonged hydrothermal activity recorded in this area by both fossil (Plio-Pleistocene ore deposits) and active (Larderello geothermal field) systems.

  1. Energy 101: Geothermal Heat Pumps

    ScienceCinema

    None

    2013-05-29

    An energy-efficient heating and cooling alternative, the geothermal heat pump system moves heat from the ground to a building (or from a building to the ground) through a series of flexible pipe "loops" containing water. This edition of Energy 101 explores the benefits Geothermal and the science behind how it all comes together.

  2. Energy 101: Geothermal Heat Pumps

    SciTech Connect

    None

    2011-01-01

    An energy-efficient heating and cooling alternative, the geothermal heat pump system moves heat from the ground to a building (or from a building to the ground) through a series of flexible pipe "loops" containing water. This edition of Energy 101 explores the benefits Geothermal and the science behind how it all comes together.

  3. State-of-the-art of liquid waste disposal for geothermal energy systems: 1979. Report PNL-2404

    SciTech Connect

    Defferding, L.J.

    1980-06-01

    The state-of-the-art of geothermal liquid waste disposal is reviewed and surface and subsurface disposal methods are evaluated with respect to technical, economic, legal, and environmental factors. Three disposal techniques are currently in use at numerous geothermal sites around the world: direct discharge into surface waters; deep-well injection; and ponding for evaporation. The review shows that effluents are directly discharged into surface waters at Wairakei, New Zealand; Larderello, Italy; and Ahuachapan, El Salvador. Ponding for evaporation is employed at Cerro Prieto, Mexico. Deep-well injection is being practiced at Larderello; Ahuachapan; Otake and Hatchobaru, Japan; and at The Geysers in California. All sites except Ahuachapan (which is injecting only 30% of total plant flow) have reported difficulties with their systems. Disposal techniques used in related industries are also reviewed. The oil industry's efforts at disposal of large quantities of liquid effluents have been quite successful as long as the effluents have been treated prior to injection. This study has determined that seven liquid disposal methods - four surface and three subsurface - are viable options for use in the geothermal energy industry. However, additional research and development is needed to reduce the uncertainties and to minimize the adverse environmental impacts of disposal. (MHR)

  4. A Numerical Study for Groundwater Flow, Heat and Solute Transport Associated with Operation of Open-loop Geothermal System in Alluvial Aquifer

    NASA Astrophysics Data System (ADS)

    Park, D. K.; Bae, G. O.; Lee, K. K.

    2014-12-01

    The open-loop geothermal system directly uses a relatively stable temperature of groundwater for cooling and heating in buildings and thus has been known as an eco-friendly, energy-saving, and cost-efficient technique. The facility for this system was installed at a site located near Paldang-dam in Han-river, Korea. Because of the well-developed alluvium, the site might be appropriate to application of this system requiring extraction and injection of a large amount of groundwater. A simple numerical experiment assuming various hydrogeologic conditions demonstrated that regional groundwater flow direction was the most important factor for efficient operation of facility in this site having a highly permeable layer. However, a comparison of river stage data and groundwater level measurements showed that the daily and seasonal controls of water level at Paldang-dam have had a critical influence on the regional groundwater flow in the site. Moreover, nitrate concentrations measured in the monitoring wells gave indication of the effect of agricultural activities around the facility on the groundwater quality. The facility operation, such as extraction and injection of groundwater, will obviously affect transport of the agricultural contaminant and, maybe, it will even cause serious problems in the normal operation. Particularly, the high-permeable layer in this aquifer must be a preferential path for quick spreadings of thermal and contaminant plumes. The objective of this study was to find an efficient, safe and stable operation plan of the open-loop geothermal system installed in this site having the complicated conditions of highly permeable layer, variable regional groundwater flow, and agricultural contamination. Numerical simulations for groundwater flow, heat and solute transport were carried out to analyze all the changes in groundwater level and flow, temperature, and quality according to the operation, respectively. Results showed that an operation plan for only the thermal efficiency of system cannot be the best in aspect of safe and stable operation related to groundwater quality. All these results concluded that it is essential to understand various and site-specific conditions of the site in a more integrated approach for the successful application of the open-loop geothermal system.

  5. Geothermal structure of Australia's east coast basins

    NASA Astrophysics Data System (ADS)

    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 system and models quickly re-run to take advantage of the most up to date information. The thermal models we’ve produced for the SGBB are an efficient regional assessment of the geothermal resource potential in this basin system.

  6. Geothermal gas equilibria

    NASA Astrophysics Data System (ADS)

    Giggenbach, Werner F.

    1980-12-01

    Comparison of theoretical and analytical equilibrium constants based on the reactions CH4 + 2 H2O = CO2 + 4 H2, 2 NH3 = N2 + 3 H2 and iron(II)-aluminium-silicate + 2H 2S = FeS 2 + H 2 + aluminium-silicate, shows that the composition of fluids discharged from geothermal areas in New Zealand (Wairakei, Kawerau, Broadlands) reflects close to complete attainment of chemical equilibrium within the system H 2O, CO 2, H 2S, NH 3, H 2, N 2 and CH 4. Under conditions prevailing in explored geothermal systems in New Zealand, the minerals graphite (elemental carbon), anhydrite, pyrrhotite, magnetite do not appear to take part in the overall equilibrium system. The three physical parameters required to evaluate geothermal gas reactions are temperature, pressure and vapor-liquid ratios within the gas equilibration zone.

  7. Geothermal vegetable dehydration at Brady`s Hot Springs, Nevada

    Microsoft Academic Search

    1994-01-01

    This article describes the utilization of the Brady`s Springs geothermal resource for heat generation used in the food dehydration process. This geothermal system is located in the Forty-Mile Desert area of Nevada. Geothermal Food Processors, Inc. of Reno, Nevada started construction of the geothermal vegetable dehydration plant in 1978, and the plant started operations in 1979. The industrial process of

  8. Dixie Valley Engineered Geothermal System Exploration Methodology Project, Baseline Conceptual Model Report

    DOE Data Explorer

    Iovenitti, Joe

    FSR Part I presents (1) an assessment of the readily available public domain data and some proprietary data provided by Terra-Gen Power, LLC, (2) a re-interpretation of these data as required, (3) an exploratory geostatistical data analysis, (4) the baseline geothermal conceptual model, and (5) the EGS favorability/trust mapping. The conceptual model presented applies to both the hydrothermal system and EGS in the Dixie Valley region. FSR Part II presents (1) 278 new gravity stations; (2) enhanced gravity-magnetic modeling; (3) 42 new ambient seismic noise survey stations; (4) an integration of the new seismic noise data with a regional seismic network; (5) a new methodology and approach to interpret this data; (5) a novel method to predict rock type and temperature based on the newly interpreted data; (6) 70 new magnetotelluric (MT) stations; (7) an integrated interpretation of the enhanced MT data set; (8) the results of a 308 station soil CO2 gas survey; (9) new conductive thermal modeling in the project area; (10) new convective modeling in the Calibration Area; (11) pseudo-convective modeling in the Calibration Area; (12) enhanced data implications and qualitative geoscience correlations at three scales (a) Regional, (b) Project, and (c) Calibration Area; (13) quantitative geostatistical exploratory data analysis; and (14) responses to nine questions posed in the proposal for this investigation. Enhanced favorability/trust maps were not generated because there was not a sufficient amount of new, fully-vetted (see below) rock type, temperature, and stress data. The enhanced seismic data did generate a new method to infer rock type and temperature. However, in the opinion of the Principal Investigator for this project, this new methodology needs to be tested and evaluated at other sites in the Basin and Range before it is used to generate the referenced maps. As in the baseline conceptual model, the enhanced findings can be applied to both the hydrothermal system and EGS in the Dixie Valley region.

  9. User manual for GEOCITY: a computer model for cost analysis of geothermal district-heating-and-cooling systems. Volume I. Main text

    SciTech Connect

    Huber, H.D.; Fassbender, L.L.; Bloomster, C.H.

    1982-09-01

    The purpose of this model is to calculate the costs of residential space heating, space cooling, and sanitary water heating or process heating (cooling) using geothermal energy from a hydrothermal reservoir. The model can calculate geothermal heating and cooling costs for residential developments, a multi-district city, or a point demand such as an industrial factory or commercial building. GEOCITY simulates the complete geothermal heating and cooling system, which consists of two principal parts: the reservoir and fluid transmission system and the distribution system. The reservoir and fluid transmission submodel calculates the life-cycle cost of thermal energy supplied to the distribution system by simulating the technical design and cash flows for the exploration, development, and operation of the reservoir and fluid transmission system. The distribution system submodel calculates the life-cycle cost of heat (chill) delivered by the distribution system to the end-users by simulating the technical design and cash flows for the construction and operation of the distribution system. Geothermal space heating is assumed to be provided by circulating hot water through radiators, convectors, fan-coil units, or other in-house heating systems. Geothermal process heating is provided by directly using the hot water or by circulating it through a process heat exchanger. Geothermal space or process cooling is simulated by circulating hot water through lithium bromide/water absorption chillers located at each building. Retrofit costs for both heating and cooling applications can be input by the user. The life-cycle cost of thermal energy from the reservoir and fluid transmission system to the distribution system and the life-cycle cost of heat (chill) to the end-users are calculated using discounted cash flow analysis.

  10. Geothermal progress monitor: Report No. 17

    SciTech Connect

    NONE

    1995-12-01

    DOE is particularly concerned with reducing the costs of geothermal power generation, especially with the abundant moderate to low-temperature resources in the US. This concern is reflected in DOE`s support of a number of energy conversion projects. Projects which focus on the costs and performance of binary cycle technology include a commercial demonstration of supersaturated turbine expansions, which earlier studies have indicated could increase the power produced per pound of fluid. Other binary cycle projects include evaluations of the performance of various working fluid mixtures and the development and testing of advanced heat rejection systems which are desperately needed in water-short geothermal areas. DOE is also investigating the applicability of flash steam technology to low-temperature resources, as an economic alternative to binary cycle systems. A low-cost, low-pressure steam turbine, selected for a grant, will be constructed to utilize fluid discharged from a flash steam plant in Nevada. Another project addresses the efficiency of high-temperature flash plants with a demonstration of the performance of the Biphase turbine which may increase the power output of such installations with no increase in fluid flow. Perhaps the most noteworthy feature of this issue of the GPM, the 17th since its inception in 1980, is the high degree of industry participation in federally-sponsored geothermal research and development. This report describes geothermal development activities.

  11. Geothermal Education Office Homepage

    NSDL National Science Digital Library

    This site includes world maps showing geothermal sites, geothermal slide shows, geothermal facts, a glossary, and links to other sites that have geothermal information and includes classroom and public information materials.

  12. AMAS: Activity Matching Ability System.

    ERIC Educational Resources Information Center

    Edwards, Marissa

    1992-01-01

    The Activity Matching Ability System (AMAS) is a computer- based system that helps place disabled persons in suitable jobs. Discusses the assessment of job activities and of individuals to perform those activities, the matching process, benefits of using AMAS, recruitment and selection, planning, placement, identification of training needs, and…

  13. Geothermal hazards - Mercury emission

    NASA Technical Reports Server (NTRS)

    Siegel, S. M.; Siegel, B. Z.

    1975-01-01

    Enthusiasm for intensified geothermal exploration may induce many participants to overlook a long-term potential toxicity hazard possibly associated with the tapping of magmatic steam. The association of high atmospheric Hg levels with geothermal activity has been established both in Hawaii and Iceland, and it has been shown that mercury can be introduced into the atmosphere from fumaroles, hot springs, and magmatic sources. These arguments, extended to thallium, selenium, and other hazardous elements, underscore the need for environmental monitoring in conjunction with the delivery of magmatic steam to the surface.

  14. Technology Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Brame, Ray; And Others

    This guide contains 43 modules of laboratory activities for technology education courses. Each module includes an instructor's resource sheet and the student laboratory activity. Instructor's resource sheets include some or all of the following elements: module number, course title, activity topic, estimated time, essential elements, objectives,…

  15. Local Ambient Seismic Noise Survey in Dixie Valley, NV for Engineered Geothermal System Favorability Assessment

    NASA Astrophysics Data System (ADS)

    Tibuleac, I. M.; Iovenitti, J. L.; von Seggern, D. H.; Sainsbury, J.

    2013-12-01

    The primary objective of this study is to develop and test the seismic component of a calibrated exploration method that integrated geological, geophysical, and geochemical data to identify potential drilling targets for Engineered Geothermal Systems (EGS). In exploring for EGS sites, the selection criteria identified by the AltaRock Energy, Inc. (AltaRock) and University of Nevada, Reno teams are, in order of importance, (1) temperature greater than 200C at 1.5 km depth, (2) rock type at the depth of interest (porous rocks at 1-3 km); and (3) favorable stress regime (tensional environment). To improve spatial resolution, a dense seismic array (21 three-component, broadband sensors, with an overall array aperture of 45km) was installed in two deployments in Dixie Valley, NV, each deployment having a three-month duration Ambient seismic noise and signal were used to retrieve inter-station and same-station Green's Functions (GFs), to be used for subsurface imaging. We used ambient seismic noise interferometry to extract GFs from crosscorrelation of continuous records. An innovative aspect of the seismic work was estimating the receiver functions beneath the stations using noise auto-correlation which was used to image the substructure. We report results of applying the technique to estimate a P/S velocity model from the GF surface wave components and from the GF body-wave reflection component, retrieved from ambient noise and signal cross-correlation and auto-correlation beams. We interpret our results in terms of temperature, pressure and rock composition. The estimated seismic velocity model capability to infer temperature is statistically assessed, in combination with other geophysical technique results.

  16. Geothermal energy program summary

    SciTech Connect

    Not Available

    1990-01-01

    The Geothermal Technology Division (GTD) of the US Department of Energy (DOE) is charged with the lead federal role in the research and development (R D) of technologies that will assist industry in economically exploiting the nation's vast geothermal resources. The GTD R D Program represents a comprehensive, balanced approach to establishing all forms of geothermal energy as significant contributors to the nation's energy supply. It is structured both to maintain momentum in the growth of the existing hydrothermal industry and to develop long-term options offering the greatest promise for practical applications. This volume, Volume 2, contains a detailed compilation of each GTD-funded R D activity performed by national laboratories or under contract to industrial, academic, and nonprofit research institutions.

  17. Federal Geothermal Research Program Update Fiscal Year 1999

    SciTech Connect

    Not Available

    2004-02-01

    The Department of Energy (DOE) and its predecessors have conducted research and development (R&D) in geothermal energy since 1971. To develop the technology needed to harness the Nation's vast geothermal resources, DOE's Office of Geothermal and Wind Technologies oversees a network of national laboratories, industrial contractors, universities, and their subcontractors. The following mission and goal statements guide the overall activities of the Office of Geothermal and Wind Technologies. This Federal Geothermal Program Research Update reviews the specific objectives, status, and accomplishments of DOE's Geothermal Program for Federal Fiscal Year (FY) 1999. The information contained in this Research Update illustrates how the mission and goals of the Office of Geothermal and Wind Technologies are reflected in each R&D activity. The Geothermal Program, from its guiding principles to the most detailed research activities, is focused on expanding the use of geothermal energy.

  18. Use of MT3DMS for heat transport simulation of shallow geothermal systems

    NASA Astrophysics Data System (ADS)

    Molina Giraldo, N. A.; Hecht Méndez, J.; Blum, P.; Bayer, P.

    2009-12-01

    Due to the mathematical similarities between heat and mass transport, the multi-species solute transport model MT3DMS, is applied to simulate heat transport for ground source heat pump (GSHP) systems. Although in several studies solute transport models were successfully applied for simulating heat transport, they lack of providing any rigorous verification of this approach. We present a comprehensive verification of applying MT3DMS (Version 5.2) for two-dimensional (2D) and three-dimensional (3D) heat transport simulations of shallow geothermal systems. Closed systems are considered for three scenarios that are distinguished by their Péclet number (Pe): scenario 1, representing a pure conduction situation (Pe=0, no groundwater flow), scenario 2, as an intermediate case (Pe=1) and scenario 3, as a convection dominated case (Pe=10). Two verification approaches are employed: First, numerical results are compared with analytical solutions. For 2D scenarios, line-source analytical solutions for heat transport simulation are applied. For 3D scenarios, planar-source analytical solutions based on classical solute transport equations are considered. Second, MT3DMS results are compared with simulations by the established finite element code FEFLOW and the variable density code SEAWAT. The computed results are compared based on residual errors using the method of efficiencies. All results are obtained from observation points located in a straight line starting at the source and extending to the eastwards (x-axys). The overall agreements of MT3DMS with the analytical solutions for the three scenarios are satisfactory. Only slight differences are observed close to the source. This is mostly due to the impossibility to represent in a numerical model the boundary conditions of the analytical solutions (infinitesimal line source). Concerning the second verification approach, the overall agreement of MT3DMS and SEAWAT is very good. With respect to FEFLOW results, moderated to very good agreements are observed. These discrepancies are result of the inherent differences of the numerical methods used by each code. Moreover, aspects related to the definition of the source (type of source and size of the source) on each code, considerably influence the results. Despite the difference obtained in the second approach, we find that the multi-species solute transport model MT3DMS can be successfully applied for simulation of heat transport caused by the application of GSHP systems in saturated and confined porous media.

  19. Geothermal heating

    SciTech Connect

    Aureille, M.

    1982-01-01

    The aim of the study is to demonstrate the viability of geothermal heating projects in energy and economic terms and to provide nomograms from which an initial estimate may be made without having to use data-processing facilities. The effect of flow rate and temperature of the geothermal water on drilling and on the network, and the effect of climate on the type of housing are considered.

  20. Geothermal energy and the utility market -- the opportunities and challenges for expanding geothermal energy in a competitive supply market: Proceedings

    SciTech Connect

    Not Available

    1992-01-01

    Each year the Geothermal Division of the US Department of Energy conducts an in-depth review of its entire geothermal R D program. The conference serves several purposes: a status report on current R D activities, an assessment of progress and problems, a review of management issues, and a technology transfer opportunity between DOE and the US geothermal city. This year's conference, Program Review X, was held in San Francisco on March 24--26, 1992. The theme of the review, Geothermal Energy and the Utility Market -- The Opportunities and Challenges for Expanding Geothermal Energy in a Competitive Supply Market,'' focused on the needs of the electric utility sector. Geothermal energy, with its power capacity potential of 10 GWe by the year 2010, can provide reliable, enviromentally clean electricity which can help offset the projected increase in demand. Program Review X consisted of seven sessions including an opening session with presentations by Mr. Vikram Budhraja, Vice President of System Planning and Operations, Southern California Edison Company, and Mr. Richard Jaros, President and Chief Operating Officer, California Energy Company. The six technical sessions included presentations by the relevant field researchers covering DOE-sponsored R D in hydrothermal, hot dry rock, and geopressured energy. Individual projects are processed separately for the data bases.

  1. Authigenic sericite record of a fossil geothermal system: the Offenburg trough, central Black Forest, Germany

    Microsoft Academic Search

    Olaf Brockamp; Norbert Clauer; Michael Zuther

    2003-01-01

    A fossil geothermal area is hosted by the Carboniferous, Permian and Bunter sandstones of the Offenburg intramontane trough in the central Black Forest. The hydrothermal alteration is identified on the basis of newly formed sericites, which appear as pseudomorphs after feldspar and filling of pore spaces. According to K–Ar dating of sericite, serititization occurred about 145 Ma ago (Jurassic). On the

  2. Barriers and enablers to geothermal district heating system development in the United States

    Microsoft Academic Search

    Hildigunnur H. Thorsteinsson; Jefferson W. Tester

    2010-01-01

    According to the US Energy Information Administration, space and hot water heating represented about 20% of total US energy demand in 2006. Given that most of this demand is met by burning natural gas, propane, and fuel oil, an enormous opportunity exists for directly utilizing indigenous geothermal energy as a cleaner, nearly emissions-free renewable alternative. Although the US is rich

  3. Stimulation Techniques Used In Enhanced Geothermal Systems: Perspectives From Geomechanics and Rock Physics

    SciTech Connect

    Stephen L. Karner; Joel Renner

    2005-01-01

    Understanding the processes that enhance fluid flow in crustal rocks is a key step towards extracting sustainable thermal energy from the Earth. To achieve this, geoscientists need to identify the fundamental parameters that govern how rocks respond to stimulation techniques, as well as the factors that control the evolution of permeability networks. These parameters must be assessed over variety of spatial scales: from microscopic rock properties (such as petrologic, mechanical, and diagenetic characteristics) to macroscopic crustal behavior (such as tectonic and hydro-dynamic properties). Furthermore, these factors must be suitably monitored and/or characterized over a range of temporal scales before the evolutionary behavior of geothermal fields can be properly assessed. I am reviewing the procedures currently employed for reservoir stimulation of geothermal fields. The techniques are analyzed in the context of the petrophysical characteristics of reservoir lithologies, studies of wellbore data, and research on regional crustal properties. I determine common features of geothermal fields that can be correlated to spatiotemporal evolution of reservoirs, with particular attention to geomechanics and petrophysical properties. The study of these correlations can then help guide procedures employed when targeting new prospective geothermal resources.

  4. Exploration and monitoring geothermal activity using Landsat ETM + images. A case study at Aso volcanic area in Japan

    NASA Astrophysics Data System (ADS)

    Mia, Md. Bodruddoza; Nishijima, Jun; Fujimitsu, Yasuhiro

    2014-04-01

    Thermal activity monitoring in and around active volcanic areas using remote sensing is an essential part of volcanology nowadays. Three identical approaches were used for thermal activity exploration at Aso volcanic area in Japan using Landsat ETM + images. First, the conventional methods for hydrothermal alteration mapping were applied to find the most active thermal region after exploring geothermal indicator minerals. Second, we found some thermally highly anomalous regions around Nakadake crater using land surface temperature estimation. Then, the Stefan-Boltzmann equation was used for estimating and also monitoring radiative heat flux (RHF) from the most active region of about 8 km2 in and around Nakadake crater in the central part of the Aso volcano. To fulfill the required parameter in the Stefan-Boltzmann equation for radiative heat flux, the NDVI (Normalized differential vegetation index) method was used for spectral emissivity, and the mono-window algorithm was used for land surface temperature of this study area. The NDVI value was used to divide land-cover in the study area into four types: water, bare ground, mixed and vegetated land. The bare land was found within the most active region. Vegetation coverage area showed an inverse relationship with total RHF in this study as health of thermally stressed vegetation supports this relationship. The spatial distribution of spectral emissivity ranged from 0.94 to 0.99 in our study. Land surface temperature was estimated using a mono-window algorithm and was highest LST in 2008 and lowest in 2011. The results of RHF showed that the highest pixel RHF was found to be about 296 W/m2 in 2008. Total RHF was obtained of about 607 MW in 2002 and the lowest was about 354 MW in 2008. The RHF anomaly area was found the highest in 2002 and was lowest in 2011. The highest total heat discharge rate (HDR) obtained about 3918 MW in 2002 and lowest total HDR about 2289 MW in 2008 from this study area. But in the case of Nakadake crater alone, the higher thermal activity was observed in 2008 and was less in 2004. The study showed that Landsat thermal infrared is the best option for thermal activity exploration and monitoring at Aso volcano as well as in any active volcano region considering high efficiency and low cost.

  5. Monitoring of Acoustic Emissions Within Geothermal Areas in Iceland: A new Tool for Geothermal Exploration.

    NASA Astrophysics Data System (ADS)

    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.

  6. Exploration and drilling for geothermal heat in the Capital District, New York. Volume 4. Final report

    SciTech Connect

    Not Available

    1983-08-01

    The Capital District area of New York was explored to determine the nature of a hydrothermal geothermal system. The chemistry of subsurface water and gas, the variation in gravity, magnetism, seismicity, and temperature gradients were determined. Water and gas analyses and temperature gradient measurements indicate the existence of a geothermal system located under an area from Ballston Spa, southward to Altamont, and eastward toward Albany. Gravimetric and magnetic surveys provided little useful data but microseismic activity in the Altamont area may be significant. Eight wells about 400 feet deep, one 600 feet and one 2232 feet were drilled and tested for geothermal potential. The highest temperature gradients, most unusual water chemistries, and greatest carbon dioxide exhalations were observed in the vicinity of the Saratoga and McGregor faults between Saratoga Springs and Schenectady, New York, suggesting some fault control over the geothermal system. Depths to the warm fluids within the system range from 500 meters (Ballston Spa) to 2 kilometers (Albany).

  7. Exploration and drilling for geothermal heat in the Capital District, New York. Final report

    SciTech Connect

    Not Available

    1983-08-01

    The Capital District area of New York was explored to determine the nature of a hydrothermal geothermal system. The chemistry of subsurface water and gas, the variation in gravity, magnetism, seismicity, and temperature gradients were determined. Water and gas analyses and temperature gradient measurements indicate the existence of a geothermal system located under an area from Ballston Spa, southward to Altamont, and eastware toward Albany. Gravimetric and magnetic surveys provided little useful data but microseismic activity in the Altamont area may be significant. Eight wells about 400 feet deep, one 600 feet and one 2232 feet were drilled and tested for geothermal potential. The highest temperature gradients, most unusual water chemistries, and greatest carbon dioxide exhalations were observed in the vicinity of the Saratoga and McGregor faults between Saratoga Springs and Schenectady, New York, suggesting some fault control over the geothermal system. Depths to the warm fluids within the system range from 500 meters (Ballston Spa) to 2 kilometers (Albany).

  8. Helium isotopes in Icelandic geothermal systems: I. 3He, gas chemistry, and 13C relations

    NASA Astrophysics Data System (ADS)

    Poreda, R. J.; Craig, H.; Arnórsson, S.; Welhan, J. A.

    1992-12-01

    Gas samples from seventeen high-temperature and twenty-two low-temperature geothermal systems have been analyzed for chemistry and 3He /4He ratios. Within the Neo-Volcanic Zone the 3He /4He ratios show a consistent regional pattern: 14-19 times the atmospheric ratio ( RA) in the southwest, 8-11 RA in the north, and 17-26 A in central Iceland. Outside of the rift zones a mantle helium component also dominates with the highest 3He /4He ratios found in waters circulating through 9-Myold crust in Northwest Iceland (up to 29 RA). The minimum Icelandic 3He /4He ratio (excluding a methane seep east of the rift) is 8.5 RA at Kverkf joll, in central Iceland at the southern end of the narrow Northern Rift Zone; throughout the NRZ the ratios vary only from 8.5 to 10.7 RA. The Kverkf joll ratio is precisely the mean MORB ratio: (8 ± 1) RA. Thus, the mantle helium emerging at Iceland is a simple mixture of two components: MORB He (8 RA) and deep-mantle plume He with R/ RA : 29. High-temperature systems have CO 2/3He ratios of 10 9 to 10 10 that encompass the range found in MORB (1-3 × 10 9). However, the CO 2/3He values have been subjected to postmagmatic effects that alter and obscure the original magmatic CO 2/3He ratios. ?( 13C) in the fluid-phase CO 2 is well defined at -3.8%. in the high-CO 2 fluids (up to 1 mol/kg fluid), very similar to MORB values. CH 4/3He ratios vary widely, from 3 × 10 4 to 10 8. Most high-temperature systems from southwestern and northern Iceland have CH 4/3He ratios less than 10 6, while those from central Iceland have consistently higher ratios of the order of 10 7. Local conditions and possible proximity to an organic source of methane can have a strong effect on this ratio.

  9. Environmental Assessment Lakeview Geothermal Project

    SciTech Connect

    Treis, Tania

    2012-04-30

    The Town of Lakeview is proposing to construct and operate a geothermal direct use district heating system in Lakeview, Oregon. The proposed project would be in Lake County, Oregon, within the Lakeview Known Geothermal Resources Area (KGRA). The proposed project includes the following elements: � Drilling, testing, and completion of a new production well and geothermal water injection well � Construction and operation of a geothermal production fluid pipeline from the well pad to various Town buildings (i.e., local schools, hospital, and Lake County Industrial Park) and back to a geothermal water injection well This EA describes the proposed project, the alternatives considered, and presents the environmental analysis pursuant to the National Environmental Policy Act. The project would not result in adverse effects to the environment with the implementation of environmental protection measures.

  10. Utilization of geothermal energy in the mining and processing of tungsten ore. Final report

    SciTech Connect

    Erickson, M.V.; Lacy, S.B.; Lowe, G.D.; Nussbaum, A.M.; Walter, K.M.; Willens, C.A.

    1981-01-01

    The engineering, economic, and environmental feasibility of the use of low and moderate temperature geothermal heat in the mining and processing of tungsten ore is explored. The following are covered: general engineering evaluation, design of a geothermal energy system, economics, the geothermal resource, the institutional barriers assessment, environmental factors, an alternate geothermal energy source, and alternates to geothermal development. (MHR)

  11. Geothermal energy: tomorrow's alternative today. A handbook for geothermal-energy development in Delaware

    SciTech Connect

    Mancus, J.; Perrone, E.

    1982-08-01

    This is a general procedure guide to various technical, economic, and institutional aspects of geothermal development in Delaware. The following are covered: geothermal as an alternative, resource characteristics, geology, well mechanics and pumping systems, fluid disposal, direct heat utilization-feasibility, environmental and legal issues, permits and regulations, finance and taxation, and steps necessary for geothermal development. (MHR)

  12. A study on modeling and performance assessment of a heat pump system for utilizing low temperature geothermal resources in buildings

    Microsoft Academic Search

    Arif Hepbasli; M. Tolga Balta

    2007-01-01

    Low and moderate geothermal resources are found in most areas of the world. A very efficient way to heat and air-condition homes and buildings is the utilization of ground source heat pumps (GSHPs), also known as geothermal heat pump (GHPs), to obtain heat energy from low temperature geothermal resources.The present study deals with the modeling and performance evaluation of a

  13. Mapping seismic attenuation within geothermal systems using teleseisms with application to the Geysers-Clear Lake Region

    NASA Astrophysics Data System (ADS)

    Ward, Ronald W.; Young, Chi-Yuh

    1980-10-01

    Though the exact relationship between temperature and seismic attenuation has not been defined, the thermal regime of geothermal systems exhibit high seismic attenuation. The attenuation of a seismic wave is proportional to Q-1 the reciprocal of the quality factor. The reduced spectral ratio technique has been used to infer Q structure. This technique is adapted to study a geothermal system. A generalized discrete linear inversion technique is applied to the observed differential attenuation data ?t* of teleseismic P waves to obtain a discrete Q model. Errors have a large effect on the Q model in a local area. Five sources of errors are involved in the estimation of ?t*. Four levels of random errors are added to synthetic data for eight different assumed models, using 12 events and 11 stations. These data are inverted to assess the effect of the observation errors on the inferred Q structures. For signal to error ratio (S/E) above 5 the models are reproducible; between 5 and 1 a dramatic degradation of fidelity occurs; and at 1 or below, numerous low Q cells are identified as high Q and vice versa. Acquisition of more numerous, better distributed data with lower error improves the quality of the inversion. A two-dimensional Q model of the Geysers-Clear Lake geothermal area is obtained using previously reported attenuation data of six teleseismic events with S/E of 4. A high/attenuation (low Q) zone is found located in the middle crust centered southeast of Mount Hannah, roughly corroborating the gravity and P wave travel time residual models.

  14. Geothermal well stimulation

    SciTech Connect

    Sinclair, A.R.; Pittard, F.J.; Hanold, R.J.

    1980-01-01

    All available data on proppants and fluids were examined to determine areas in technology that need development for 300 to 500/sup 0/F (150/sup 0/ to 265/sup 0/C) hydrothermal wells. While fluid properties have been examined well into the 450/sup 0/F range, proppants have not been previously tested at elevated temperatures except in a few instances. The latest test data at geothermal temperatures is presented and some possible proppants and fluid systems that can be used are shown. Also discussed are alternative stimulation techniques for geothermal wells.

  15. Structural Controls of the MacFarlane Geothermal System, Humboldt County, Nevada: New Insights Based on Detailed Geologic Mapping, Shallow Temperature Surveys, and Magnetic Data

    NASA Astrophysics Data System (ADS)

    Kraushaar, Sabina M.

    Detailed geologic mapping, structural analysis, magnetic and two-meter temperature data, integrated with previous datasets, constrain the structural controls of the MacFarlane geothermal system. MacFarlane hot springs and the travertine fissure ridges lie within a relay ramp. The relay ramp is formed between two overlapping, north-northeast-striking, west-dipping Holocene normal faults exposed in Lake Lahontan sediments. Other mapped faults near the hot spring include a north-striking, west-dipping Tertiary fault east of MacFarlane hot springs. The highest temperature gradient is found at the projected intersection between the Tertiary and north-northeast-striking Quaternary fault, ˜2.5 km northeast of the hot spring (Sibbett et al., 1982; Swanberg and Bowers, 1982). Our new data suggest other controls involving the relay ramp geometry of the Holocene faults. The anomalous orientation of the travertine fissure ridge motivated this study of the structural controls of the geothermal system. MacFarlane hot spring is located on the eastern margin of the Black Rock Desert, ˜85 km west of Winnemucca, in Humboldt County, Nevada. The active hot spring emerges from the west end of an east-trending travertine fissure ridge, which is ˜180 m long. The travertine fissure ridge is up to ˜2 m tall and ˜5 m wide, and has a central fissure along its long axis. The orientation of the travertine fissure ridge indicates local north-south extension, which is inconsistent with the regional west-northwest extension of the northwestern Basin and Range province. The anomalous travertine orientation is due to fractures that occurred during formation of a relay ramp between two overlapping fault segments.

  16. Assessing innovation in emerging energy technologies: Socio-technical dynamics of carbon capture and storage (CCS) and enhanced geothermal systems (EGS) in the USA

    Microsoft Academic Search

    Jennie C. Stephens; Scott Jiusto

    2010-01-01

    This study applies a socio-technical systems perspective to explore innovation dynamics of two emerging energy technologies with potential to reduce greenhouse gas emissions from electrical power generation in the United States: carbon capture and storage (CCS) and enhanced geothermal systems (EGS). The goal of the study is to inform sustainability science theory and energy policy deliberations by examining how social

  17. Direct utilization of geothermal energy for space and water heating at Marlin, Texas. Final report

    SciTech Connect

    Conover, M.F.; Green, T.F.; Keeney, R.C.; Ellis, P.F. II; Davis, R.J.; Wallace, R.C.; Blood, F.B.

    1983-05-01

    The Torbett-Hutchings-Smith Memorial Hospital geothermal heating project, which is one of nineteen direct-use geothermal projects funded principally by DOE, is documented. The five-year project encompassed a broad range of technical, institutional, and economic activities including: resource and environmental assessments; well drilling and completion; system design, construction, and monitoring; economic analyses; public awareness programs; materials testing; and environmental monitoring. Some of the project conclusions are that: (1) the 155/sup 0/F Central Texas geothermal resource can support additional geothermal development; (2) private-sector economic incentives currently exist, especially for profit-making organizations, to develop and use this geothermal resource; (3) potential uses for this geothermal resource include water and space heating, poultry dressing, natural cheese making, fruit and vegetable dehydrating, soft-drink bottling, synthetic-rubber manufacturing, and furniture manufacturing; (4) high maintenance costs arising from the geofluid's scaling and corrosion tendencies can be avoided through proper analysis and design; (5) a production system which uses a variable-frequency drive system to control production rate is an attractive means of conserving parasitic pumping power, controlling production rate to match heating demand, conserving the geothermal resource, and minimizing environmental impacts.

  18. Ambulatory physical activity monitoring system.

    PubMed

    Makikawa, M; Kurata, S; Kawato, M; Kobayashi, H; Takahashi, A; Tokue, R

    1998-01-01

    In this study, we have developed an ambulatory behaviour map and physical activity monitoring system by equipping our portable digital biosignal memory device developed previously with a GPS sensor and piezoresistive accelerometers. By this system, we can get the subjects behaviour map, his physical activities and posture changes in daily life. PMID:10384461

  19. Thermodynamics of geothermal fluids

    Microsoft Academic Search

    P. S. Z. Rogers; P. S. Z

    1981-01-01

    A model to predict the thermodynamic properties of geothermal brines, based on a minimum amount of experimental data on a few key systems, is tested. Volumetric properties of aqueous sodium chloride, taken from the literature, are represented by a parametric equation over the range 0 to 3000 C and 1 bar to 1 kbar. Density measurements at 20 bar needed

  20. Geothermal Grows Up

    ERIC Educational Resources Information Center

    Johnson, William C.; Kraemer, Steven; Ormond, Paul

    2011-01-01

    Self-declared energy and carbon reduction goals on the part of progressive colleges and universities have driven ground source geothermal space heating and cooling systems into rapid evolution, as part of long-term climate action planning efforts. The period of single-building or single-well solutions is quickly being eclipsed by highly engineered…

  1. Geothermal pipeline

    SciTech Connect

    Not Available

    1992-12-01

    A number of new ideas for geothermal power development and use have been proposed or initiated. British engineers have proposed using North Sea oil rigs as geothermal power stations. These stations would use the low temperature heat from the water that now occupies the former oil reservoirs to generate electricity. NASA recently retrofitted its engine test facility to enable it to use warm water from an underground aquifer as source water in a heat pump. A major policy guideline regarding electricity is issued by the California Energy Commission (CEC) every two years. This year, CEC appears to be revising its method for determining the total societal cost of various electricity supply options. The change may impact geothermal energy usage in a positive way. Virtually untapped geothermal resources in Preston, Idaho will be utilized for warm water catfish farming. Stockton State College in New Jersey will be the site of one of the nation's largest geothermal projects when it is completed in 1993. It is designed to satisfy the college's energy requirements at an estimated cost savings of $300,000 per year. Aquaculture projects using thermal springs are under consideration in Utah and Washington State. Utah may be the site of an alligator farm and Washington State is being considered for raising golden tilapia, a food fish.

  2. Design of a pressure/temperature logging system for geothermal applications

    SciTech Connect

    Lysne, P.; Henfling, J.

    1994-04-01

    Past memory logging tools have provided excellent pressure/temperature data when used in a geothermal environment, and they are easier to maintain and deploy than tools requiring an electric wireline connection to the surface. However, they are deficient since the tool operator is unaware of downhole conditions that could require changes in the logging program. Tools that make ``decisions`` based on preprogrammed scenarios can partially overcome this difficulty, and a suite of such memory tools is under development at Sandia. The first tool, which forms the basis for future instruments, measures pressure and temperature. Design considerations include a minimization of cost while insuring quality data, size compatibility with diamond-cored holes, use in holes to 425{degree}C (800{degree}F), transportability by ordinary passenger air service, and ease of operation. Prototype tools are available for evaluation by the geothermal industry.

  3. Efficiency of vertical geothermal heat exchangers in the ground source heat pump system

    NASA Astrophysics Data System (ADS)

    Zeng, Heyi; Diao, Nairen; Fang, Zhaohong

    2003-02-01

    Taking the fluid temperature distribution along the borehole depth into account, a new quasi-three-dimensional model for vertical ground heat exchangers has been established, which provides a better understanding of the heat transfer processes in the geothermal heat exchangers. On this basis the efficiency of the borehole has been defined and its analytical expression derived. Comparison with the previous two-dimensional model shows that the quasi-three-dimensional model is more rational and more accurate to depict the practical feature of the conduction of geothermal heat exchanger, and the efficiency notion can be easily used to determine the inlet and outlet temperature of the circulating fluid inside the heat exchanger.

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

    SciTech Connect

    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.

  5. Decision analysis for geothermal energy

    E-print Network

    Yost, Keith A

    2012-01-01

    One of the key impediments to the development of enhanced geothermal systems is a deficiency in the tools available to project planners and developers. Weak tool sets make it difficult to accurately estimate the cost and ...

  6. Coupled Three-Dimensional Fracture Stimulation and Prediction Model for Enhanced Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Kumar, D.; Gutierrez, M.

    2013-12-01

    The paper presents development of a three-dimensional fracture stimulation and prediction model using the Boundary Element Method (BEM) for Enhanced Geothermal Systems (EGS). The BEM method results in a numerical procedure which eliminates discretization of complete reservoir domain; hence, only the fracture surface discretization is required. The Displacement Discontinuity Method which is an invariant of the BEM was used to model the fracture geometry (e.g., fracture width, length and elongation), fluid pressure and stress distribution around the fracture. The main feature of the model is that it is able to handle true three-dimensional fractures that can twist turn and not just planar or pseudo three-dimensional fracture geometries. The numerical aspects of various mechanisms involved in the hydraulic fracturing process in the EGS such as fracture deformation, fluid flow and heat flow, fracture initiation and propagation were addressed. The laminar fracture fluid flow and transient heat flow were modeled using the Finite Element Method. The non-Newtonian fluid flow behavior was assumed. Temperature-dependent fluid and rock physical properties were used. The fracture same mesh was used to model for the fracture deformation, fluid flow and heat flow processes. The fracture surface was discretized using 4-node rectangular elements. The important numerical issues of the BEM implementation for the fracture modeling such as near singular, hypersingular cases and crack tip singularity were taken into account. The processes involved in hydraulic fracturing are interdependent. The fracture aperture strongly influences the fluid flow rate inside the fracture, as the fluid velocity is proportional to its width. Thermal-induced stresses effects the fracture aperture. These fully coupled processes of fluid flow, heat flow, and fracture deformation were solved in a coupled manner using iterative method. One of the main challenges of this research was to couple the thermal induced changes due to differential cooling of reservoir rocks with the fracture model. Parametric studies were done to quantify the effects of different fluid injection rate and temperature, and fluid properties on the fracture geometry.

  7. A stress-dependent model for reservoir stimulation in enhanced geothermal systems

    NASA Astrophysics Data System (ADS)

    Troiano, Antonio; Giulia Di Giuseppe, Maria; Troise, Claudia; De Natale, Giuseppe

    2015-04-01

    We present a procedure for testing the interpretation of the induced seismicity. The procedure is based on Coulomb stress changes induced by deep fluid injection during well stimulation, providing a way to estimate how the potential for seismic failure in different volumes of a geothermal reservoir might change due to the water injection. Coulomb stress changes appear to be the main cause for the induced seismicity during the water injection. These stress changes do not only result from changes in the pore pressure, but also from the whole change in the stress tensor at any point in the medium, which results from the pressure perturbations. The numerical procedure presented takes into account the permeability increase that is due to the induced stress changes. A conceptual model that links the induced stress tensor and the permeability modifications is considered to estimate the permeability change induced during the water injection. In this way, we can adapt the medium behavior to mechanical changes, in order to better evaluate the effectiveness of the stimulation process for the enhancement of the reservoir permeability, while also refining the reconstruction of the Coulomb stress change patterns. Numerical tests have been developed that consider a physical medium and a geometry of the system comparable with that of Soultz EGS site (Alsace, France). Tests considering a fixed permeability, both isotropic and anisotropic, indicate a general decrease in the pressure changes when an anisotropic permeability was considered, with respect to the isotropic case. A marked elongation of the coulomb stress change patterns in the regional load direction was retrieved. This effect is enforced when a stress-dependent permeability is taken into account. Permeability enhancement progressively enlarges the seismic volume in turns, while decreasing the pressure in the neighborhood of the bottom of the well. The use of stress-dependent permeability also improves the reconstruction of the observed seismicity pattern. In particular, the large maximum of the coulomb stress changes at the point of injection, which was already mitigated by the consideration of anisotropic permeability, appears further decreased in the new data. The improving of the correlation between the coulomb stress changes and the induced seismicity distribution supports the reliability and robustness of the main hypothesis of this study of the relationship between the induced stress tensor variation and the permeability enhancement. The use of stress-dependent permeability constitutes an important step towards the theoretical planning of stimulation procedures, and towards interpretation and mitigation of the induced seismicity.

  8. Numerical modeling of the high-temperature geothermal system of Amatitlan, Guatemala

    SciTech Connect

    Pham, M.; Menzies, A.J.; Sanyal, S.K. [GeothermEx, Inc., Richmond, CA (United States)] [and others

    1996-12-31

    Using the conceptual model of the Amatitlin geothermal system as a guide, a 14 by 10 km numerical model was set up with five layers and a total of 1,220 grid blocks. The number of grid blocks varies from layer to layer, with finer resolution in the two production layers. Boundary blocks for conductive heat transfer, heat and mass recharge, shallow discharge and deep regional fluid flow were added to the model as appropriate. With an inflow of hot fluid (336{degrees}C) at a rate of 450 tones per hour, an inflow of cool fluid (50{degrees}C) at a rate of 620 tons per hour and permeabilities varying from 1.5 to 50 md, the initial state temperatures on all five levels were well matched by the numerical model. The initial state results indicate that highest permeability is present to the southeast of the productive wells, suggesting that considerable additional production potential exists in this area. A two-phase region exists in the upper levels of the reservoir and in the outflow plume; the latter is consistent with the presence of fumaroles along the shoreline of Lago de Amatitlan. To further calibrate the numerical model, enthalpy and pressure data collected during tests of wells AMF-1 and -2 were matched, primarily by varying reservoir storage capacity. Good matches to the observed data were obtained for both wells, although sharp transients could not be matched. Modeling proceeded to the prediction stage under two scenarios: production of 12 and 25 MW (gross) for 30 years. 100% injection of separated water and condensate was assumed to take place in the vicinity of well AMF-3 in both cases. The results show an increase in enthalpy caused by expansion of the two-phase zone during the first year of production, followed by an enthalpy decline as reservoir liquid begins to migrate toward the production area. The two existing production wells (AMF-1 and -2) are predicted to be capable of maintaining output in the 12 MW case throughout the 30-year project life.

  9. Information systems and technology transfer programs on geothermal energy and other renewable sources of energy

    SciTech Connect

    Lippmann, Marcelo J.; Antunez, Emilio u.

    1996-01-24

    In order to remain competitive it is necessary to stay informed and use the most advanced technologies available. Recent developments in communication, like the Internet and the World Wide Web, enormously facilitate worldwide data and technology transfer. A compilation of the most important sources of data on renewable energies, especially geothermal, as well as lists of relevant technology transfer programs are presented. Information on how to gain access to, and learn more about them is also given.

  10. Information systems and technology transfer programs on geothermal energy and other renewable sources of energy

    SciTech Connect

    Lippmann, M.J.; Antunez, E.

    1996-01-01

    In order to remain competitive, it is necessary to stay informed and use the most advanced technologies available. Recent developments in communication, like the Internet and the World Wide Web, enormously facilitate worldwide data and technology transfer. A compilation of the most important sources of data on renewable energies, especially geothermal, as well as lists of relevant technology transfer programs are presented. Information on how to gain access to, and learn more about them, is also given.

  11. Session: Geopressured-Geothermal

    SciTech Connect

    Jelacic, Allan J.; Eaton, Ben A.; Shook, G. Michael; Birkinshaw, Kelly; Negus-de Wys, Jane

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Overview of Geopressured-Geothermal'' by Allan J. Jelacic; ''Geothermal Well Operations and Automation in a Competitive Market'' by Ben A. Eaton; ''Reservoir Modeling and Prediction at Pleasant Bayou Geopressured-Geothermal Reservoir'' by G. Michael Shook; ''Survey of California Geopressured-Geothermal'' by Kelly Birkinshaw; and ''Technology Transfer, Reaching the Market for Geopressured-Geothermal Resources'' by Jane Negus-de Wys.

  12. On modeling of chemical stimulation of an enhanced geothermal system using a high pH solution with chelating agent

    SciTech Connect

    Xu, T.; Rose, P.; Fayer, S.; Pruess, K.

    2009-05-01

    Dissolution of silica and calcite in the presence of a chelating agent (NTA) at a high pH was successfully demonstrated in laboratory experiments using a high-temperature flow reactor. (Note that the term 'silica' used here includes amorphous silica, quartz, and silicate glass bead). The mineral dissolution and associated porosity enhancement in the experiments were reproduced by reactive transport modeling using TOUGHREACT. The chemical stimulation method was applied by numerical modeling to a field geothermal injection well system to investigate its effectiveness. Parameters applicable to the quartz monzodiorite unit at the Enhanced Geothermal Systems (EGS) site at Desert Peak (Nevada) were used. Results indicate that the injection of a high pH chelating solution results in dissolution of both calcite and plagioclase, while avoiding precipitation of calcite at high temperature conditions. Consequently reservoir porosity and permeability can be enhanced especially near the injection well. Injection at a lower temperature of 120 C (over 160 C in the base-case) results in a porosity increase that is smaller close to the injection point, but extends to a larger radial distance. A slower kinetic rate results in less aggressive mineral dissolution close to the injection point and larger extent along the flow path, which is favorable for chemical stimulation.

  13. Sixth workshop on geothermal reservoir engineering: Proceedings

    SciTech Connect

    Ramey, H.J. Jr.; Kruger, P. (eds.)

    1980-12-18

    INTRODUCTION TO THE PROCEEDINGS OF THE SIXTH GEOTHERMAL RESERVOIR ENGINEERING WORKSHOP, STANFORD GEOTHERMAL PROGRAM Henry J. Ramey, Jr., and Paul Kruger Co-Principal Investigators Ian G. Donaldson Program Manager Stanford Geothermal Program The Sixth Workshop on Geothermal Reservoir Engineering convened at Stanford University on December 16, 1980. As with previous Workshops the attendance was around 100 with a significant participation from countries other than the United States (18 attendees from 6 countries). In addition, there were a number of papers from foreign contributors not able to attend. Because of the success of all the earlier workshops there was only one format change, a new scheduling of Tuesday to Thursday rather than the earlier Wednesday through Friday. This change was in general considered for the better and will be retained for the Seventh Workshop. Papers were presented on two and a half of the three days, the panel session, this year on the numerical modeling intercomparison study sponsored by the Department of Energy, being held on the second afternoon. This panel discussion is described in a separate Stanford Geothermal Program Report (SGP-TR42). This year there was a shift in subject of the papers. There was a reduction in the number of papers offered on pressure transients and well testing and an introduction of several new subjects. After overviews by Bob Gray of the Department of Energy and Jack Howard of Lawrence Berkeley Laboratory, we had papers on field development, geopressured systems, production engineering, well testing, modeling, reservoir physics, reservoir chemistry, and risk analysis. A total of 51 papers were contributed and are printed in these Proceedings. It was, however, necessary to restrict the presentations and not all papers printed were presented. Although the content of the Workshop has changed over the years, the format to date has proved to be satisfactory. The objectives of the Workshop, the bringing together of researchers, engineers and managers involved in geothermal reservoir study and development and the provision of a forum for the prompt and open reporting of progress and for the exchange of ideas, continue to be met . Active discussion by the majority of the participants is apparent both in and outside the workshop arena. The Workshop Proceedings now contain some of the most highly cited geothermal literature. Unfortunately, the popularity of the Workshop for the presentation and exchange of ideas does have some less welcome side effects. The major one is the developing necessity for a limitation of the number of papers that are actually presented. We will continue to include all offered papers in the Summaries and Proceedings. As in the recent past, this sixth Workshop was supported by a grant from the Department of Energy. This grant is now made directly to Stanford as part of the support for the Stanford Geothermal Program (Contract No. DE-AT03-80SF11459). We are certain that all participants join us in our appreciation of this continuing support. Thanks are also due to all those individuals who helped in so many ways: The members of the program committee who had to work so hard to keep the program to a manageable size - George Frye (Aminoil USA), Paul G. Atkinson (Union Oil Company). Michael L. Sorey (U.S.G.S.), Frank G. Miller (Stanford Geothermal Program), and Roland N. Horne (Stanford Geothermal Program). The session chairmen who contributed so much to the organization and operation of the technical sessions - George Frye (Aminoil USA), Phillip H. Messer (Union Oil Company), Leland L. Mink (Department of Energy), Manuel Nathenson (U.S.G.S.), Gunnar Bodvarsson (Oregon State University), Mohindar S. Gulati (Union Oil Company), George F. Pinder (Princeton University), Paul A. Witherspoon (Lawrence Berkeley Laboratory), Frank G. Miller (Stanford Geothermal Program) and Michael J. O'Sullivan (Lawrence Berkeley Laboratory). The many people who assisted behind the scenes, making sure that everything was prepared and organized - in particular we would like to t

  14. Assessing the Impact of the Installation of a Community-Scale Closed-Loop Ground-Source Geothermal System on Underlying Aquifers: Ball State University, Muncie, IN

    NASA Astrophysics Data System (ADS)

    Neumann, K.; Dowling, C.; Florea, L.; Dunn, M.; Samuelson, A. C.; Lowe, J.

    2013-12-01

    Ball State University (BSU), located within the city of Muncie, Indiana, began installing the nation's largest ground-source geothermal project in 2009. Currently, BSU is burning over 20,000 tons of coal annually to satisfy heating and cooling demands of the school and is one of the largest emitters of CO2, SO2 and mercury in the city of Muncie and surrounding Delaware County. The elimination of coal burning will reduce aerial pollution by an estimated 1400 tons of SO2 and 4 pounds of mercury annually, once the system is fully operational. Currently, the groundsource geothermal system is being installed in Phases. Phase 1 includes 1803 400-ft deep geothermal boreholes that were drilled in a 15x15 ft grid in two large fields (North and South) in the northern part of campus. Two geothermal exchange loops were installed in each borehole to add or remove heat from the ground. BSU students and faculty collected hydrogeologic and temperature data from a series of groundwater monitoring wells, beginning Summer 2010. The installation of the second phase in the southern part of campus has commenced.. Despite the rise in community-scale ground-source geothermal energy systems, there is very little empirical information on their effects upon the groundwater environment, or, vice versa, of the effects of the groundwater flow pattern on the geothermal field. Previous studies have triggered concern over the impact of large-scale geothermal systems where increases in groundwater temperatures were documented. We will demonstrate how, since BSU initiated Phase 1 in late November 2011 with cold-water circulation (adding heat to the ground), the temperature increased over 10 degrees Celsius in the center of the South Field, with temperatures rising in other surrounding monitoring wells depending on groundwater movement and their distance from the edge of the geothermal boreholes. The temperature increases are distinctively different in the upper highly hydraulically conductive aquifers (Quaternary till) and the underlying poorly conductive formations (Ordovician and Silurian limestone and shale). Maintaining a temperature differential between the exchange loops and the geologic substrate and/or groundwater is crucial to the long term efficiency of the system, and continued monitoring both of the hydrology and engineering aspects of the project will be necessary.

  15. Geothermal initiatives in Central America

    SciTech Connect

    Hanold, R.J.; Loose, V.W.; Laughlin, A.W.; Wade, P.E.

    1986-01-01

    The US Agency for International Development is supporting a new project in energy and resources exploitation for Central America. One of the largest components of the project involves exploration and reservoir development investigations directed at enhancing the production of electricity from the region's geothermal resources. An assessment of the geothermal resources of Honduras is in progress, and interesting geothermal regions in the Guanacaste Province of Costa Rica are being explored. Well-logging activities are in progress in the production wells at the Miravalles geothermal field in Costa Rica, and preparations are being made for logging critical wells at Ahuachapan in El Salvador. A self-contained logging truck, complete with high-temperature logging cable and logging tools designed for geothermal service, is being fabricated and will be made available for dedicated use throughout Central America. Geochemical and isotopic analyses of water samples collected in Panama are being evaluated to select a high-priority geothermal site in that country. Application of low- and medium-enthalpy geothermal fluids for industrial and agricultural processes is being investigated in Guatemala.

  16. Geothermal mineralized scales in the pipe system of the geothermal Piancastagnaio power plant (Mt. Amiata geothermal area): a key to understand the stibnite, cinnabarite and gold mineralization of Tuscany (central Italy)

    NASA Astrophysics Data System (ADS)

    Morteani, Giulio; Ruggieri, Giovanni; Möller, Peter; Preinfalk, Christine

    2011-02-01

    The CO2-rich geothermal fluids produced in the Piancastagnaio geothermal field (Mt. Amiata geothermal area, Southern Tuscany, Italy) show temperatures up to 360°C and pressures of about 200 bar at depths of around 3,500 m (Giolito, Ph.D. thesis, Università degli Studi di Firenze, Italy, pp 1-147, 2005). CaCO3- and/or SiO2-dominated scales are deposited in the pipes leading to the pressure and atmospheric separators of the geothermal wells. High content of metastibnite and/or stibnite in both calcite and silica scales and Sb contents of up to 50 mg/L in the fluids indicate their mineralising potential. The red or black colours of the scales depend on the predominance of red metastibnite or black stibnite, respectively. In our condensation experiments, as well as during deposition of the scales, metastibnite is the first Sb2S3 mineral to form. In a second stage, metastibnite is transformed to stibnite. During depressurization the Hg content of geothermal fluids partitions preferentially into the gas phase, whereas Sb and As remain in the liquid phase. This separation explains the often observed areal separation of Hg and Sb mineralization. The multistage deposition of Sb in the mining district of Tuscany is due to a periodic restoration of the permeability of the ore-bearing faults by microseismic events and subsequent host rock brecciation. The still ongoing microseismic events are induced by the accumulation of high-pressure CO2-rich fluids along faults followed by mechanical failure of the faults.

  17. Geothermal Gradients

    NSDL National Science Digital Library

    Cameron Davidson

    In this problem set the students use two different equations to calculate a conductive geothermal gradient using a spreadsheet program like Excel. Once they have the geothermal gradient plotted, they are asked to experiment with and comment on the model by changing parameters (e.g. mantle heat flow, thermal conductivity). There is a mix of specific, fill in the blank questions and open-ended questions. This problem set helps develop quantitative problem solving skills using a spreadsheet as a tool, and forces students to think about thermal constraints during igneous and metamorphic processes.

  18. Thermodynamics of geothermal fluids

    NASA Astrophysics Data System (ADS)

    Rogers, P. S. Z.

    1981-03-01

    A model to predict the thermodynamic properties of geothermal brines, based on a minimum amount of experimental data on a few key systems, is tested. Volumetric properties of aqueous sodium chloride, taken from the literature, are represented by a parametric equation over the range 0 to 3000 C and 1 bar to 1 kbar. Density measurements at 20 bar needed to complete the volumetric description also are presented. The pressure dependence of activity and thermal properties, derived from the volumetric equation, can be used to complete an equation of state for sodium chloride solutions. A flow calorimeter, used to obtain heat capacity data at high temperatures and pressures, is described. Heat capacity measurements, from 30 to 2000 C and 1 bar to 200 bar, are used to derive values for the activity coefficient and other thermodynamic properties of sodium sulfate solutions as a function of temperature. Literature data on the solubility of gypsum in mixed electrolyte solutions are used to evaluate model parameters for calculating gypsum solubility in seawater and natural brines. Predictions of strontium and barium sulfate solubility in seawater also are given.

  19. Thermodynamics of geothermal fluids

    NASA Astrophysics Data System (ADS)

    Rogers, P. S. Z.

    A model to predict the thermodynamic properties of geothermal brines, based on a minimum amount of experimental data on a few key systems, was tested. Volumetric properties of aqueous sodium chloride, taken from the literature, are represented by a parametric equation over the range 0 C to 300 C and 1 bar to 1 kbar. Density measurements at 20 bar needed to complete the volumetric description also are presented. The pressure dependence of activity and thermal properties, derived from the volumetric equation, were used to complete an equation of state for sodium chloride solutions. A flow calorimeter used to obtain heat capacity data at high temperatures and pressures is described. Heat capacity measurements from 30 C to 200 C and 1 bar to 200 bar are used to derive values for the activity coefficient and other thermodynamic properties of sodium sulfate solutions as a function of temperature. Literature data on the solubility of gypsum in mixed electrolyte solutions was used to evaluate model parameters for calculating gypsum solubility in seawater and natural brines. Predictions of strontium and barium sulfate solubility in seawater are also given.

  20. Schools using geothermal energy in Iowa

    NSDL National Science Digital Library

    Iowa Public Television. Explore More Project

    2004-01-01

    How can geothermal energy be used in public buildings? This reading, part of a series about the future of energy, provides students with information on the use of geothermal energy in schools in Iowa. Students view a table that lists the names of the five schools, describes the benefits of the geothermal systems being used, and specifies the design of the system. Copyright 2005 Eisenhower National Clearinghouse

  1. Portable active interrogation system.

    SciTech Connect

    Moss, C. E. (Calvin E.); Brener, M. W. (Mathieu W.); Hollas, C. L. (Charles L.); Myers, W. L. (William L.)

    2004-01-01

    The system consists of a pulsed DT neutron generator (5 x 10{sup 7} n/s) and a portable but high intrinsic efficiency, custom-designed, polyethylene-moderated {sup 3}He neutron detector. A multichannel scaler card in a ruggedized laptop computer acquires the data. A user-friendly LabVIEW program analyzes and displays the data. The program displays a warning message when highly enriched uranium or any other fissionable materials is detected at a specified number of sigmas above background in the delayed region between pulses. This report describes the system and gives examples of the response of the system to highly enriched uranium and some other fissionable materials, at several distances and with various shielding materials.

  2. Numerical simulation to study the feasibility of using CO2 as a stimulation agent for enhanced geothermal systems

    SciTech Connect

    Xu, T.; Zhang, W.; Pruess, K.

    2009-11-15

    A major concern in the development of enhanced geothermal systems (EGS) is achieving and maintaining adequate injectivity, while avoiding the development of preferential short-circuiting flow paths such as those caused by thermally-induced stress cracking. Past researches have tended to focus primarily on thermal and hydraulic stimulation. Recent studies suggest that chemical stimulation may improve the performance of EGS reservoirs. Geothermal injection wells are often drilled into formations containing reactive minerals such as calcite. Injecting aqueous chemical agents such as mineral acids, could be effective for mineral dissolution and porosity enhancement at distances of several meters around a well. An alternative to treatment with strong acids is the use of supercritical (SC) CO{sub 2} as stimulation agent for an aqueous-based EGS. Reactive transport modeling is used to investigate the effectiveness of this method. We used the thermal condition and mineralogical composition from a well of Desert Peak EGS site, to examine ways in which mixtures of water and CO{sub 2} can be injected to enhance porosity.

  3. Thirteenth workshop on geothermal reservoir engineering: Proceedings

    SciTech Connect

    Ramey, H.J. Jr.; Kruger, P.; Horne, R.N.; Brigham, W.E.; Miller, F.G.; Cook, J.W. (Stanford Geothermal Program)

    1988-01-21

    PREFACE The Thirteenth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 19-21, 1988. Although 1987 continued to be difficult for the domestic geothermal industry, world-wide activities continued to expand. Two invited presentations on mature geothermal systems were a keynote of the meeting. Malcolm Grant presented a detailed review of Wairakei, New Zealand and highlighted plans for new development. G. Neri summarized experience on flow rate decline and well test analysis in Larderello, Italy. Attendance continued to be high with 128 registered participants. Eight foreign countries were represented: England, France, Iceland, Italy, New Zealand, Japan, Mexico and The Philippines. A discussion of future workshops produced a strong recommendation that the Stanford Workshop program continue for the future. There were forty-one technical presentations at the Workshop. All of these are published as papers in this Proceedings volume. Four technical papers not presented at the Workshop are also published. In addition to these forty five technical presentations or papers, the introductory address was given by Henry J. Ramey, Jr. from the Stanford Geothermal Program. The Workshop Banquet speaker was Gustavo Calderon from the Inter-American Development Bank. We thank him for sharing with the Workshop participants a description of the Bank???s operations in Costa Rica developing alternative energy resources, specifically Geothermal, to improve the country???s economic basis. His talk appears as a paper in the back of this volume. The chairmen of the technical sessions made an important contribution to the workshop. Other than Stanford faculty members they included: J. Combs, G. T. Cole, J. Counsil, A. Drenick, H. Dykstra, K. Goyal, P. Muffler, K. Pruess, and S. K. Sanyal. The Workshop was organized by the Stanford Geothermal Program faculty, staff and students. We would like to thank Marilyn King, Pat Oto, Terri Ramey, Bronwyn Jones, Yasmin Gulamani, and Rosalee Benelli for their valued help with the meeting arrangements and preparing the Proceedings. We also owe great thanks to our students who arranged and operated the audio-visual equipment, especially Jeralyn Luetkehans. The Thirteenth Workshop was supported by the Geothermal Technology Division of the U.S. Department of Energy through Contract No. DE-AS07-84ID12529. We deeply appreciate this continued support. Henry J. Ramey, Jr. Paul Kruger Roland N. Horne William E. Brigham Frank G. Miller Jean W. Cook

  4. U.S. Department of Energy: Geothermal Technologies Office

    NSDL National Science Digital Library

    The U.S. Department of Energy's Geothermal Technologies Program addresses its work in the advancement of geothermal energy production. The website details the interesting history of geothermal energy in the United States, beginning more than 10,000 years ago with the settlement of Paleo-Indians at a hot springs. Visitors can learn the basics of geothermal energy and can view an animation of how an enhanced geothermal system works. Researchers can learn about the Program's investigations in energy systems, exploration and drilling, and geoscience and geothermal energy's appli

  5. The Iceland Deep Drilling Project (IDDP): Deep Fluid Sampling in Fractured Quartz, Reykjanes Geothermal System, Iceland

    NASA Astrophysics Data System (ADS)

    Seward, R. J.; Reed, M. H.; Grist, H. R.; Fridriksson, T.; Danielsen, P.; Thorhallsson, S.; Elders, W. A.; Fridleifsson, G. O.

    2011-12-01

    In July of 2011 a fluid inclusion tool (FIT) was deployed in well RN-17b of the Reykjanes geothermal system, Iceland, with the goal of sampling fluids in situ at the deepest feed point in the well. The tool consists of a perforated stainless steel pipe containing eight stainless steel mesh canisters, each loaded with 10mm-scale blocks of thermally fractured quartz. Except for one control canister, in each canister the fractured quartz blocks were surrounded by a different grain size of SiO¬2 glass that ranged in size from 10?m-scale glass wool to cm-scale glass shards. The FIT was left in the well on a wireline at a depth of 2768m and retrieved after three weeks. The fluid at 2768m depth is known from November 2010 well logs to have a temperature of about 330°C and pressure of 170 bars, a pressure ~40 bar too high for boiling at that temperature. After retrieval, quartz in all of the canisters contained liquid-dominated fluid inclusions, but their quantity and size differed by canister. Groups of inclusions occur in healed fractures and both healed and open fracture surfaces are visible within single quartz blocks. Measurements on a heating and cooling stage yield approximant inclusion homogenization temperatures of 332°C and freezing points of -2.0°C. These measurements and a pressure of 170 bars yield trapping temperatures of 335°C and a NaCl weight percent of 3.4, both of which match known values, thus verifying that the device trapped fluids as intended. In upcoming studies, these fluids will be analyzed using bulk methods and LA-ICP-MS on individual inclusions. The glass added to the quartz blocks in the canisters allowed the Reykjanes fluids to precipitate enough quartz to heal fractures and trap fluids despite the fluid undersaturation in quartz. Almost all of the glass that was added to the canisters, 27 to 66 grams in each (except glass wool), was consumed in the experiment. Remaining glass was in the non-mesh bottom caps of the canisters where fluid flux may have been minimal, indicating that most of the dissolved SiO2 was carried away with flowing fluid. This may explain why not all fractures were healed, as they were in our previous closed-system laboratory experiments. Upon recovery from the well, the FIT and the canister contents were covered in fine black particles, the greatest quantity by far occurring in canisters that had contained glass wool as the SiO2 source. Preliminary SEM-EDS analyses show that the particles contain silica, iron, magnesium, and small amounts of zinc sulfide. The precipitation of sulfides from the fluid sampled in the quartz fractures provides a valuable constraint on interpretation of the fluid inclusion compositions.

  6. PROCEEDINGS, Thirty-Sixth Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, January 31 -February 2, 2011

    E-print Network

    Stanford University

    system allows data transmission without a continuous fluid column. Operating the Coso geothermal fieldPROCEEDINGS, Thirty-Sixth Workshop on Geothermal Reservoir Engineering Stanford University AND PDM SYSTEMS IMPROVE DRILLING PERFORMANCE IN A CALIFORNIA GEOTHERMAL WELL Dennis Lovett, Terra

  7. Characterization of a geothermal system in the Upper Arkansas Valley, CO Thomas Blum*, Kasper van Wijk and Lee Liberty, Boise State University

    E-print Network

    Arkansas Basin. Abbreviations: BV, Buena Vista, CCHS, Cottonwood Canyon Hot Springs; HHS, Hortense Hot Springs; MPHS, Mount Princeton Hot Springs; PS, Poncha Springs; S, Salida. The location of the crossCharacterization of a geothermal system in the Upper Arkansas Valley, CO Thomas Blum*, Kasper van

  8. Energy and temperature performance analysis of geothermal (ground source) heat pumps integrated with permeable pavement systems for urban run-off reuse