Sample records for california geothermal field

  1. Laboratory measurements of reservoir rock from the Geysers geothermal field, California (United States)

    Lockner, D.A.; Summers, R.; Moore, D.; Byerlee, J.D.


    Rock samples taken from two outcrops, as well as rare cores from three well bores at the Geysers geothermal field, California, were tested at temperatures and pressures similar to those found in the geothermal field. Both intact and 30?? sawcut cylinders were deformed at confining pressures of 200-1000 bars, pore pressure of 30 bars and temperatures of 150?? and 240??C. Thin-section and X-ray analysis revealed that some borehole samples had undergone extensive alteration and recrystallization. Constant strain rate tests of 10-4 and 10-6 per sec gave a coefficient of friction of 0.68. Due to the highly fractured nature of the rocks taken from the production zone, intact samples were rarely 50% stronger than the frictional strength. This result suggests that the Geysers reservoir can support shear stresses only as large as its frictional shear strength. Velocity of p-waves (6.2 km/sec) was measured on one sample. Acoustic emission and sliding on a sawcut were related to changes in pore pressure. b-values computed from the acoustic emissions generated during fluid injection were typically about 0.55. An unusually high b-value (approximately 1.3) observed during sudden injection of water into the sample may have been related to thermal cracking. ?? 1982.

  2. Monitoring reservoir response to earthquakes and fluid extraction, Salton Sea geothermal field, California. (United States)

    Taira, Taka'aki; Nayak, Avinash; Brenguier, Florent; Manga, Michael


    Continuous monitoring of in situ reservoir responses to stress transients provides insights into the evolution of geothermal reservoirs. By exploiting the stress dependence of seismic velocity changes, we investigate the temporal evolution of the reservoir stress state of the Salton Sea geothermal field (SSGF), California. We find that the SSGF experienced a number of sudden velocity reductions (~0.035 to 0.25%) that are most likely caused by openings of fractures due to dynamic stress transients (as small as 0.08 MPa and up to 0.45 MPa) from local and regional earthquakes. Depths of velocity changes are estimated to be about 0.5 to 1.5 km, similar to the depths of the injection and production wells. We derive an empirical in situ stress sensitivity of seismic velocity changes by relating velocity changes to dynamic stresses. We also observe systematic velocity reductions (0.04 to 0.05%) during earthquake swarms in mid-November 2009 and late-December 2010. On the basis of volumetric static and dynamic stress changes, the expected velocity reductions from the largest earthquakes with magnitude ranging from 3 to 4 in these swarms are less than 0.02%, which suggests that these earthquakes are likely not responsible for the velocity changes observed during the swarms. Instead, we argue that velocity reductions may have been induced by poroelastic opening of fractures due to aseismic deformation. We also observe a long-term velocity increase (~0.04%/year) that is most likely due to poroelastic contraction caused by the geothermal production. Our observations demonstrate that seismic interferometry provides insights into in situ reservoir response to stress changes.

  3. Monitoring reservoir response to earthquakes and fluid extraction, Salton Sea geothermal field, California (United States)

    Taira, Taka’aki; Nayak, Avinash; Brenguier, Florent; Manga, Michael


    Continuous monitoring of in situ reservoir responses to stress transients provides insights into the evolution of geothermal reservoirs. By exploiting the stress dependence of seismic velocity changes, we investigate the temporal evolution of the reservoir stress state of the Salton Sea geothermal field (SSGF), California. We find that the SSGF experienced a number of sudden velocity reductions (~0.035 to 0.25%) that are most likely caused by openings of fractures due to dynamic stress transients (as small as 0.08 MPa and up to 0.45 MPa) from local and regional earthquakes. Depths of velocity changes are estimated to be about 0.5 to 1.5 km, similar to the depths of the injection and production wells. We derive an empirical in situ stress sensitivity of seismic velocity changes by relating velocity changes to dynamic stresses. We also observe systematic velocity reductions (0.04 to 0.05%) during earthquake swarms in mid-November 2009 and late-December 2010. On the basis of volumetric static and dynamic stress changes, the expected velocity reductions from the largest earthquakes with magnitude ranging from 3 to 4 in these swarms are less than 0.02%, which suggests that these earthquakes are likely not responsible for the velocity changes observed during the swarms. Instead, we argue that velocity reductions may have been induced by poroelastic opening of fractures due to aseismic deformation. We also observe a long-term velocity increase (~0.04%/year) that is most likely due to poroelastic contraction caused by the geothermal production. Our observations demonstrate that seismic interferometry provides insights into in situ reservoir response to stress changes. PMID:29326977

  4. Project Title: Geothermal Play Fairway Analysis of Potential Geothermal Resources in NE California, NW Nevada, and Southern Oregon: A Transition between Extension$-$Hosted and Volcanically$-$Hosted Geothermal Fields

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    McClain, James S. [Univ. of California, Davis, CA (United States). Dept. of; Dobson, Patrick [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Glassley, William [Univ. of California, Davis, CA (United States). Dept. of Earth and Planetary Sciences; Schiffman, Peter [Univ. of California, Davis, CA (United States). Dept. of Earth and Planetary Sciences; Zierenberg, Robert [Univ. of California, Davis, CA (United States). Dept. of Earth and Planetary Sciences; Zhang, Yingqi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Conrad, Mark [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Siler, Drew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gasperikova, Erika [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Spycher, Nicolas F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)


    Final report for the UCD-LBNL effort to apply Geothermal Play Fairway Analysis to a transition zone between a volcanically-hosted and extensionally-hosted geothermal. The project focusses on the geothermal resources in northeastern California.

  5. Geothermal resources of California sedimentary basins (United States)

    Williams, C.F.; Grubb, F.V.; Galanis, S.P.


    The 2004 Department of Energy (DOE) Strategic Plan for geothermal energy calls for expanding the geothermal resource base of the United States to 40,000 MW of electric power generating potential. This will require advances in technologies for exploiting unconventional geothermal resources, including Enhanced Geothermal Systems (EGS) and geopressured geothermal. An investigation of thermal conditions in California sedimentary basins through new temperature and heat flow measurements reveals significant geothermal potential in some areas. In many of the basins, the combined cooling effects of recent tectonic and sedimentary processes result in relatively low (geothermal gradients. For example, temperatures in the upper 3 km of San Joaquin, Sacramento and Ventura basins are typically less than 125??C and do not reach 200??c by 5 km. By contrast, in the Cuyama, Santa Maria and western Los Angeles basins, heat flow exceeds 80 mW/m2 and temperatures near or above 200??C occur at 4 to 5 km depth, which represents thermal conditions equivalent to or hotter than those encountered at the Soultz EGS geothermal site in Europe. Although the extractable geothermal energy contained in these basins is not large relative to the major California producing geothermal fields at The Geysers or Salton Sea, the collocation in the Los Angeles basin of a substantial petroleum extraction infrastructure and a major metropolitan area may make it attractive for eventual geothermal development as EGS technology matures.

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

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


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

  7. Recent Changes in Ground Deformation at the East Mesa Geothermal Field, California as Measured by InSAR (United States)

    Taylor, H.; Pritchard, M. E.; Lohman, R. B.


    The East Mesa Geothermal Field in East Mesa, Imperial County, California is a series of 6 geothermal power plants with a 57MW capacity that has been in operation since 1987. Previous InSAR studies using ERS-1 and ERS-2 data (1992-2001) have observed ongoing subsidence at rates between -32 to -43 mm/yr. The observed subsidence at this site was thought to be caused by reservoir compaction since there was a negative net production of water during that time period. However, even though net production remained negative, more recent Envisat data reveal a shift in the subsidence signal towards the north and onset of relative uplift in the south portion of the geothermal field starting in 2006. We examine three datasets over East Mesa, including 57 descending ERS-1 and ERS-2 SAR images as well as 35 ascending and 48 descending Envisat SAR acquisitions, to create more than 900 interferograms over the 18 year time period (1992-2010). This dense temporal coverage is valuable for evaluating variations in deformation patterns and minimizing the contribution from the atmosphere. A modified version of the small baseline subset (SBAS) method is used to generate time series of ground displacements and average velocities. ERS data are consistent with previous studies showing rates between -30 and -40 mm/year in the line-of-sight while the Envisat time series' show line-of-sight rates of -20 mm/yr and 12 mm/yr for maximum subsidence and uplift. Net production at the East Mesa Geothermal Field is calculated using production and injection data provided by the California Department of Conservation. The average net production is estimated as -383,000 metric tons per month over the time span of Envisat data and remained negative even during the onset of relative uplift.

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

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

  9. Gas and Isotope Geochemistry of 81 Steam Samples from Wells in The Geysers Geothermal Field, Sonoma and Lake Counties, California (United States)

    Lowenstern, Jacob B.; Janik, Cathy J.; Fahlquist, Lynne; Johnson, Linda S.


    The Geysers geothermal field in northern California, with about 2000-MW electrical capacity, is the largest geothermal field in the world. Despite its importance as a resource and as an example of a vapor-dominated reservoir, very few complete geochemical analyses of the steam have been published (Allen and Day, 1927; Truesdell and others, 1987). This report presents data from 90 steam, gas, and condensate samples from wells in The Geysers geothermal field in northern California. Samples were collected between 1978 and 1991. Well attributes include sampling date, well name, location, total depth, and the wellhead temperature and pressure at which the sample was collected. Geochemical characteristics include the steam/gas ratio, composition of noncondensable gas (relative proportions of CO2, H2S, He, H2, O2, Ar, N2, CH4, and NH3), and isotopic values for deltaD and delta18O of H2O, delta13C of CO2, and delta34S of H2S. The compilation includes 81 analyses from 74 different production wells, 9 isotopic analyses of steam condensate pumped into injection wells, and 5 complete geochemical analyses on gases from surface fumaroles and bubbling pools. Most samples were collected as saturated steam and plot along the liquid-water/steam boiling curve. Steam-togas ratios are highest in the southeastern part of the geothermal field and lowest in the northwest, consistent with other studies. Wells in the Northwest Geysers are also enriched in N2/Ar, CO2 and CH4, deltaD, and delta18O. Well discharges from the Southeast Geysers are high in steam/gas and have isotopic compositions and N2/Ar ratios consistent with recharge by local meteoric waters. Samples from the Central Geysers show characteristics found in both the Southeast and Northwest Geysers. Gas and steam characteristics of well discharges from the Northwest Geysers are consistent with input of components from a high-temperature reservoir containing carbonrich gases derived from the host Franciscan rocks. Throughout the

  10. Micro-seismicity and seismic moment release within the Coso Geothermal Field, California (United States)

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


    We relocate 16 years of seismicity in the Coso Geothermal Field (CGF) using differential travel times and simultaneously invert for seismic velocities to improve our knowledge of the subsurface geologic and hydrologic structure. We expand on our previous results by doubling the number of relocated events from April 1996 through May 2012 using a new field-wide 3-D velocity model. Relocated micro-seismicity sharpens in many portions of the active geothermal reservoir, likely defining large-scale fault zones and fluid pressure compartment boundaries. However, a significant fraction of seismicity remains diffuse and does not cluster into sharply defined structures, suggesting that permeability is maintained within the reservoir through distributed brittle failure. The seismic velocity structure reveals heterogeneous distributions of compressional (Vp) and shear (Vs) wave speed, with Vs generally higher in the Main Field and East Flank and Vp remaining relatively uniform across the CGF, but with significant local variations. The Vp/Vs ratio appears to outline the two main producing compartments of the reservoir at depths below mean ground level of approximately 1 to 2.5 km, with a ridge of relatively high Vp/Vs separating the Main Field from the East Flank. Detailed analyses of spatial and temporal variations in earthquake relocations and cumulative seismic moment release in the East Flank reveal three regions with persistently high rates of seismic activity. Two of these regions exhibit sharp, stationary boundaries at the margins of the East Flank that likely represent barriers to fluid flow and advective heat transport. However, seismicity and moment release in a third region at the northern end of the East Flank spread over time to form an elongated NE to SW structure, roughly parallel both to an elongated cluster of seismicity at the southern end of the East Flank and to regional fault traces mapped at the surface. Our results indicate that high

  11. Micro-seismicity within the Coso Geothermal field, California, from 1996-2012 (United States)

    Kaven, Joern; Hickman, Stephen H.; Weber, Lisa C.


    We extend our previous catalog of seismicity within the Coso Geothermal field by adding over two and a half years of additional data to prior results. In total, we locate over 16 years of seismicity spanning from April 1996 to May of 2012 using a refined velocity model, apply it to all events and utilize differential travel times in relocations to improve the accuracy of event locations. The improved locations elucidate major structural features within the reservoir that we interpret to be faults that contribute to heat and fluid flow within the reservoir. Much of the relocated seismicity remains diffuse between these major structural features, suggesting that a large volume of accessible and distributed fracture porosity is maintained within the geothermal reservoir through ongoing brittle failure. We further track changes in b value and seismic moment release within the reservoir as a whole through time. We find that b values decrease significantly during 2009 and 2010, coincident with the occurrence of a greater number of moderate magnitude earthquakes (3.0 ≤ ML Coso reservoir is comprised of a network of fractures at a variety of spatial scales that evolves dynamically over time, with progressive changes in characteristics of microseismicity and inferred fractures and faults that are only evident from a long period of seismic monitoring analyzed using self-consistent methods.

  12. Geothermal resource investigations, Imperial Valley, California. Status report

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    The discussion is presented under the following chapter titles: geothermal resource investigations, Imperial Valley, California; the source of geothermal heat; status of geothermal resources (worldwide); geothermal aspects of Imperial Valley, California; potential geothermal development in Imperial Valley; environmental considerations; and proposed plan for development. (JGB)

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

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


    Since high concentrations of radionuclides and high temperatures are not normally encountered in salt domes or beds, finding an exact geologic analog of expected near-field conditions in a mined nuclear waste repository in salt will be difficult. The Salton Sea Geothermal Field, however, provides an opportunity to investigate the migration and retardation of naturally occurring U, Th, Ra, Cs, Sr and other elements in hot brines which have been moving through clay-rich sedimentary rocks for up to 100,000 years. The more than thirty deep wells drilled in this field to produce steam for electrical generation penetrate sedimentary rocks containing concentrated brines where temperatures reach 365/sup 0/C at only 2 km depth. The brines are primarily Na, K, Ca chlorides with up to 25% of total dissolved solids; they also contain high concentrations of metals such as Fe, Mn, Li, Zn, and Pb. This report describes the geology, geophysics and geochemistry of this system as a prelude to a study of the mobility of naturally occurring radionuclides and radionuclide analogs within it. The aim of this study is to provide data to assist in validating quantitative models of repository behavior and to use in designing and evaluating waste packages and engineered barriers. 128 references, 33 figures, 13 tables.

  14. Temporal changes of static stress drop as a proxy for poroelastic effects at The Geysers geothermal field, California (United States)

    Staszek, Monika; Orlecka-Sikora, Beata; Lasocki, Stanislaw; Kwiatek, Grzegorz; Leptokaropoulos, Konstantinos; Martinez-Garzon, Patricia


    One of the major environmental impacts of shale gas exploitation is triggered and induced seismicity. Due to the similarity of fluid injection process data from geothermal fields can be used as a proxy for shale gas exploitation associated seismicity. Therefore, in this paper we utilize 'The Geysers' dataset compiled within SHale gas Exploration and Exploitation induced Risks (SHEER) project. The dependence of earthquake static stress drops on pore pressure in the medium was previously suggested by Goertz-Allmann et al. (2011), who observed an increase of the static stress drop with the distance from injection well during reservoir stimulation at Deep Heat Mining project in Basel, Switzerland. Similar observation has been done by Kwiatek et al. (2014) in Berlín geothermal field, El Salvador. In this study, we use a high-quality data from The Geysers geothermal field to determine whether the static stress drops and the stress drop distributions change statistically significantly in time or not, and how such changes are correlated with the values of hypocenter depth, water injection rate, and distance from injection well. For the analyses we use a group of 354 earthquakes, which occurred in the proximity of Prati-9 and Prati-29 injection wells. Spectral parameters of these earthquakes were determined using mesh spectral ratio technique. Our results indicate that: (1) the static stress drop variation in time is statistically significant, (2) median static stress drop is inversely related to median injection rate. Therefore, it is highly expected that static stress drop is influenced by pore pressure in underground fluid injection conditions. References: Goertz-Allmann B., Goertz A., Wiemer S. (2011), Stress drop variations of induced earthquakes at the Basel geothermal site. Geophysical Research Letters, 38, L09308, doi:10.1029/2011GL047498. Kwiatek G., Bulut F., Bohnhoff M., Dresen G. (2014), High-resolution analysis of seismicity induced at Berlin geothermal field

  15. California Geothermal Forum: A Path to Increasing Geothermal Development in California

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    Young, Katherine R. [National Renewable Energy Lab. (NREL), Golden, CO (United States)


    The genesis of this report was a 2016 forum in Sacramento, California, titled 'California Geothermal Forum: A Path to Increasing Geothermal Development in California.' The forum was held at the California Energy Commission's (CEC) headquarters in Sacramento, California with the primary goal being to advance the dialogues for the U.S. Department of Energy's Geothermal Technologies Office (GTO) and CEC technical research and development (R&D) focuses for future consideration. The forum convened a diverse group of stakeholders from government, industry, and research to lay out pathways for new geothermal development in California while remaining consistent with critical Federal and State conservation planning efforts, particularly at the Salton Sea.

  16. Geothermal energy in California: Status report

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    Citron, O.; Davis, C.; Fredrickson, C.; Granit, R.; Kerrisk, D.; Leibowitz, L.; Schulkin, B.; Wornack, J.


    The potential for electric energy from geothermal resources in California is currently estimated to be equivalent to the output from 14 to 21 large (1000 MW) central station power plants. In addition, since over 30 California cities are located near potential geothermal resources, the non-electric applications of geothermal heat (industrial, agriculture, space heating, etc.) could be enormous. Therefore, the full-scale utilization of geothermal resources would have a major impact upon the energy picture of the state. This report presents a summary of the existing status of geothermal energy development in the state of California as of the early part of 1976. The report provides data on the extent of the resource base of the state and the present outlook for its utilization. It identifies the existing local, state, and federal laws, rules and regulations governing geothermal energy development and the responsibilities of each of the regulatory agencies involved. It also presents the differences in the development requirements among several counties and between California and its neighboring states. Finally, it describes on-going and planned activities in resource assessment and exploration, utilization, and research and development. Separate abstracts are prepared for ERDA Energy Research Abstracts (ERA) for Sections II--VI and the three Appendixes.

  17. Deformation near the Casa Diablo geothermal well field and related processes Long Valley caldera, Eastern California, 1993-2000 (United States)

    Howle, J.F.; Langbein, J.O.; Farrar, C.D.; Wilkinson, S.K.


    Regional first-order leveling lines, which extend from Lee Vining, CA, to Tom's Place, CA, have been surveyed periodically since 1957 by the U.S. Geological Survey (USGS), the National Geodetic Survey (NGS), and Caltrans. Two of the regional survey lines, or leveling networks, intersect at the Casa Diablo geothermal well field. These leveling networks, referenced to a distant bench mark (C916) near Lee Vining, provide time-series vertical control data of land-surface deformation that began around 1980. These data are also useful for delineating localized subsidence at Casa Diablo related to reservoir pressure and temperature changes owing to geothermal development that began in 1985. A comparison of differences in bench-mark elevations for five time periods between 1983 and 1997 shows the development and expansion of a subsidence bowl at Casa Diablo. The subsidence coincides spatially with the geothermal well field and temporally with the increased production rates and the deepening of injection wells in 1991, which resulted in an increase in the rate of pressure decline. The subsidence, superimposed on a broad area of uplift, totaled about 310 mm by 1997. The USGS established orthogonal tilt arrays in 1983 to better monitor deformation across the caldera. One tilt array (DBR) was established near what would later become the Casa Diablo geothermal well field. This array responded to magmatic intrusions prior to geothermal development, tilting away from the well field. With the start of geothermal fluid extraction in 1985, tilt at the DBR array reversed direction and began tilting into the well field. In 1991, geothermal power production was increased by a factor of four, and reservoir pressures began a period of steep decline. These changes caused a temporary three-fold increase in the tilt rate. The tilt rate became stable in 1993 and was about 40% lower than that measured in 1991-1992, but still greater than the rates measured during 1985-1990. Data from the

  18. Micro-seismicity, fault structure, and hydrologic compartmentalization within the Coso Geothermal Field, California, from 1996 until present (United States)

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


    Geothermal reservoirs derive their capacity for fluid and heat transport in large part from faults and fractures. In conventional reservoirs, preexisting faults and fractures are the main conduits for fluid flow, while in enhanced geothermal systems (EGS), fractures and faults that are generated or enlarged (i.e., through increases in surface area and aperture) by hydraulic stimulation provide the main pathways for fluids and heat. In both types of geothermal systems, seismicity can be used to locate active faults, which can act either as conduits for along-fault fluid flow and/or barriers to cross-fault flow. We relocate 14 years of seismicity in the Coso Geothermal Field (CGF) using differential travel time relocations to improve our knowledge of the subsurface geologic and hydrologic structure. The seismicity at Coso has been recorded on a local network operated by the Navy Geothermal Program, which provides exceptional coverage and quality of data. Using the relocated catalog, we employ a newly developed algorithm for fault identification using the spatial seismicity distribution and a priori constraints on fault zone width derived from local geologic mapping. We avoid having to assume a particular fault-normal seismicity distribution by finding regions of maximum spatial seismicity density. Assuming a maximum spatial density is physically plausible since faults, or more accurately fault zones, generate most of the associated seismicity within a central fault core or damage zone. These techniques are developed for naturally occurring, active faults within the CGF on which seismicity is induced, in part, by changes in production and injection. They can also be applied to EGS if seismicity is induced within newly created fracture systems of comparable width or if this seismicity is generated by stimulating pre-existing, partially sealed faults. The results of the relocations reveal that clouds of seismicity shrink into distinct oblate volumes of seismicity in

  19. Geothermal energy: opportunities for California commerce. Phase I report

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    California's geographic and end-use markets which could directly use low and moderate temperature geothermal resources are ranked and described, as well as those which have the highest potential for near-term commercial development of these resources. Building on previous market surveys, the assessment determined that out of 38 geothermal resource areas with characteristics for direct use development, five areas have no perceived impediments to near-term development: Susanville, Litchfield, Ontario Hot Springs, Lake Elsinore, and the Salton Sea Geothermal Field. Twenty-nine applications were compared with previously selected criteria to determine their near-term potential for direct use of geothermal fluids. Seven categories were found to have the least impediments to development; agriculture and district heating applications are considered the highest. Ten-year projections were conducted for fossil fuel displacement from the higher rated applications. It is concluded that greenhouses have the greatest displacement of 18 x 10/sup 6/ therms per year.

  20. Using micro-seismicity and seismic velocities to map subsurface geologic and hydrologic structure within the Coso geothermal field, California (United States)

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


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

  1. Hydrochemical-isotopic and hydrogeological conceptual model of the Las Tres Vı´rgenes geothermal field, Baja California Sur, México (United States)

    Portugal, E.; Birkle, P.; Barragán R, R. M.; Arellano G, V. M.; Tello, E.; Tello, M.


    Based on geological, structural, hydrochemical and isotopic data, a hydrogeological conceptual model for the geothermal reservoir, shallow wells and springs at the Las Tres Vı´rgenes geothermal field and its surroundings is proposed. The model explains the genesis of different types of thermal and cold groundwater in the NW (El Azufre Valley, Las Tres Vı´rgenes and Aguajito complex), NE (Reforma complex) and S (Sierra Mezquital) areas. Shallow groundwater of sulfate type in the NW zone is explained by the rise of CO2-H2S vapor from a shallow magma chamber and the subsequent heating up of a shallow aquifer. Vertical communication between the reservoir and the surface is facilitated by a series of extensional, NW-SE-trending normal faults, forming the graben structures of the Santa Rosalı´a Basin. Low-permeability characteristics of the geological formations of the study area support the hypothesis of a fracture and fault-dominated, subterranean-flow circulation system. The Na- (Cl-HCO3) composition of springs in the NE and SE zones indicates influence of ascending geothermal fluids, facilitated by radial fault systems of the Reforma caldera and probably the existence of a shallow magma chamber. Close to the surface, the rising geothermal fluids are mixed up with meteoric water from a shallow aquifer. The Las Tres Vı´rgenes and the Reforma complex are separated by younger, N-S-trending lateral shearing faults, such as the Cimarrón fault; such disposition explains the genesis of different hydrogeological flow regimes on both sides. HCO3-type surface water from the southern zone between San Ignacio and Mezquital is of typical meteoric origin, with no influence of geothermal fluids. Due to arid climatic conditions in the study zone, recent recharge in the geothermal area seems improbable; thus, recent interaction between the surface and the geothermal reservoir can be excluded. Furthermore, isotopic and hydrochemical data exclude the presence of marine water

  2. An application of neural network in geophysical prospecting. Electrical resistivity at Las Virgenes geothermal field, Baja California Sur, Mexico; Una aplicacion de las redes neuronales a la prospeccion geofisica. Resistividad electrica en las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Palma Guzman, Sergio Hugo [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)


    The technology of the neural network is presented with geophysical focus in the Las Virgenes geothermal field, Baja California Sur, Mexico. The results obtained when extrapolating the associative data of the prospecting magnetoteluria and Vertical Electric Sounding, on the area of the geothermal wells to the rest of the area, allows to classify zones of interest for the geothermal exploitation. Also, the use of these associative parameters with the information of the stabilized temperature of the wells, they allow to predict temperatures for the rest of the area. [Spanish] Se presenta una aplicacion de la tecnologia de las redes neuronales con enfoque geofisico en el campo geotermico de Las Virgenes, Baja California Sur, Mexico. Los resultados obtenidos al extrapolar los datos asociativos de las prospecciones geoelectricas de magnetoteluria y sondeos electricos verticales, en la zona de los pozos geotermicos al resto del area, permiten clasificar zonas de interes para la explotacion geotermica. Tambien, la utilizacion de estos parametros asociativos con la informacion de la temperatura estabilizada de los pozos, permiten predecir temperaturas para la misma area.

  3. Geothermal emissions data base, Wairakei geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, S.R. (comp.)


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

  4. Market Analysis of Geothermal Energy for California and Hawaii

    Energy Technology Data Exchange (ETDEWEB)



    This is one of the earlier market analyses for geothermal electric power and direct heat. The market for geothermal power was found to be large enough to absorb anticipated developments in California. For direct use, geothermal resources and urban markets in CA and HI are not well collocated.

  5. Reconnaissance geothermal resource assessment of 40 sites in California

    Energy Technology Data Exchange (ETDEWEB)

    Leivas, E.; Martin, R.C.; Higgins, C.T.; Bezore, S.P.


    Results are set forth for a continuing reconnaissance-level assessment of promising geothermal sites scattered through California. The studies involve acquisition of new data based upon field observations, compilation of data from published and unpublished sources, and evaluation of the data to identify areas suitable for more intensive area-specific studies. Forty sites were chosen for reporting on the basis of their relative potential for development as a significant resource. The name and location of each site is given, and after a brief synopsis, the geothermal features, chemistry, geology, and history of the site are reported. Three sites are recommended for more detailed study on the basis of potential for use by a large number of consumers, large volume of water, and the likelihood that the resource underlies a large area. (LEW)

  6. Land subsidence in the Cerro Prieto Geothermal Field, 1 Baja California, Mexico, from 1994 to 2005. An integrated analysis of DInSAR, levelingand geological data.

    Energy Technology Data Exchange (ETDEWEB)

    Sarychikhina, O; Glowacka, E; Mellors, R; Vidal, F S


    Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994- 1997 and 1997-2006) and detailed geological information in order to improve the understanding of temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the spatial pattern of the subsidence as well as changes in rate are highly correlated with the development of the Cerro Prieto Geothermal Field.

  7. Microfossils from Cerro Prieto geothermal wells, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Cotton, M.L.; Vonder Haar, S.


    To aid in a paleoenvironmental and age reconstruction of the Cerro Prieto reservoir system, 59 samples of well cuttings were analyzed for microfossils. The cuttings were obtained at depths from 351 to 3495 m in 14 geothermal wells in the Cerro Prieto field, Baja California, Mexico. We found foraminifera in 6 samples, ostracodes in 19 samples, and nannoplankton as coccoliths in 24 samples. Other groups, such as molluscs, insects, fish skeletal parts, and plant material were occasionally present. Detailed interpretations are not possible at this time because of poor preservation of samples. This is primarily due to causes: dissolution by geothermal fluids that reach 350{sup 0}C, and the extensive mixing of filled Cretaceous forms (reworked from the Colorado Plateau region) with Tertiary species during drilling. Further studies of ostracodes and foraminifera from colder portions of the wells are needed. The abundant and well-preserved ostracodes indicate marine to brackish water environments that correspond, in part, to lagoonal or estuarine facies. The presence of the mid-Tertiary (15-My-old) marine foraminifera, Cassigerinela chipolensis, in wells M-11 and M-38, 350 to 500 m deep, is perplexing. These are not laboratory contaminates and, as yet, have not been found in the drilling mud. If further studies confirm their presence at Cerro Prieto, established ideas about the opening of the Gulf of California and about Pacific Coast mid-Tertiary history will need to be rewritten.

  8. Microfossils from Cerro Prieto geothermal wells, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Cotton, M.L.; Haar, S.V.


    To aid in a paleonenvironmental and age reconstruction of the Cerro Prieto reservoir system, 59 samples of well cuttings were analyzed for microfossils. The cuttings were obtained at depths from 351 to 3495m in 14 geothermal wells in the Cerro Prieto field, Baja California, Mexico. Foraminifera was found in 6 samples, ostracodes in 19 samples and mannoplankton as coccoliths in 24 samples. Other groups, such as molluscus, insects, fish skeletal parts, and plant material were occasionally present. Detailed interpretations at this time cannot be made because of poor preservation of samples. This is primarily due to causes: dissolution by geothermal fluids that reach 350/sup 0/C, and the extensive mixing of filled Cretaceous forms (reworked from the Colorado Plateau region) with Tertiary species during drilling. Further studies of ostracodes and foraminifera from colder portions of the wells are needed. The abundant and well-preserved ostracodes indicate marine to backish water inviroments that correspond in part, to lagoonal or estuarine facies. The presence of the mid-Tertiary (15-m.y.-old) marine foraminifera, Cassigerinela chipolensis, in wells M-11 and M-38, 350 to 500m deep, is perplexing. These are not laboratory contaminates and, as yet have not been found in the drilling mud. If further studies confirm their presence at Cerro Prieto, established ideas about the opening of the Gulf of California and about Pacific Coast mid-Tertiary history will need to be rewritten.

  9. Deformation study of Kamojang geothermal field (United States)

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


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

  10. Correlation of wireline log characteristics with hydrothermal alteration and other reservoir properties of the Salton Sea and Westmorland geothermal fields, Imperial Valley, California, USA

    Energy Technology Data Exchange (ETDEWEB)

    Muramoto, F.S.; Elders, W.A.


    A detailed study of wireline logs from 11 wells in the Salton Sea and Westmorland geothermal systems was undertaken in order to determine the effects of hydrothermal alteration on the response of electrical and gamma-gamma density well logs. For the Salton Sea geothermal field, definite correspondence between log responses and hydrothermal mineralogy is evident, which in turn is related to the physical properties of the rocks. Three hydrothermal and one unaltered zone can be identified from log data on shales. These are: (1) the unaltered montmorillonite zone (<100/sup 0/ to 190/sup 0/C); (2) the illite zone (100/sup 0/ to 190/sup 0/C to 230/sup 0/ to 250/sup 0/C); (3) the chlorite zone (230/sup 0/ to 250/sup 0/C to 290/sup 0/ to 300/sup 0/C); and (4) the feldspar zone (>290/sup 0/ to 300/sup 0/C). The characteristic responses on well logs by which these zones are identified result primarily from changes in clay mineralogy of the shales and increases in density with progressive hydrothermal metamorphism. In the Westmorland geothermal field, differentiating mineral zones from log responses was only partially successful. However, analyses of both well log and petrologic data for wells Landers 1 and Kalin Farms 1 suggest that the former is heating up and the latter is cooling.

  11. Population analysis relative to geothermal energy development, Imperial County, California

    Energy Technology Data Exchange (ETDEWEB)

    Pick, J.B.; Jung, T.H.; Butler, E.


    The historical and current population characteristics of Imperial County, California, are examined. These include vital rates, urbanization, town sizes, labor force composition, income, utility usage, and ethnic composition. Inferences are drawn on some of the important social and economic processes. Multivariate statistical analysis is used to study present relationships between variables. Population projections for the County were performed under historical, standard, and geothermal projection assumptions. The transferability of methods and results to other geothermal regions anticipating energy development is shown. (MHR)

  12. Evaluation of the Geothermal Public Power Utility Workshops in California

    Energy Technology Data Exchange (ETDEWEB)

    Farhar, B. C.


    The federal government devotes significant resources to educating consumers and businesses about geothermal energy. Yet little evidence exists for defining the kinds of information needed by the various audiences with specialized needs. This paper presents the results of an evaluation of the Geothermal Municipal Utility Workshops that presented information on geothermal energy to utility resource planners at customer-owned utilities in California. The workshops were sponsored by the Western Area Power Administration and the U.S. Department of Energy's GeoPowering the West Program and were intended to qualitatively assess the information needs of municipal utilities relative to geothermal energy and get feedback for future workshops. The utility workshop participants found the geothermal workshops to be useful and effective for their purposes. An important insight from the workshops is that utilities need considerable lead-time to plan a geothermal project. They need to know whether it is better to own a project or to purchase geothermal electricity from another nonutility owner. California customer-owned utilities say they do not need to generate more electricity to meet demand, but they do need to provide more electricity from renewable resources to meet the requirements of the state's Renewable Portfolio Standard.

  13. Environmental assessmental, geothermal energy, Heber geothermal binary-cycle demonstration project: Imperial County, California

    Energy Technology Data Exchange (ETDEWEB)


    The proposed design, construction, and operation of a commercial-scale (45 MWe net) binary-cycle geothermal demonstration power plant are described using the liquid-dominated geothermal resource at Heber, Imperial County, California. The following are included in the environmental assessment: a description of the affected environment, potential environmental consequences of the proposed action, mitigation measures and monitoring plans, possible future developmental activities at the Heber anomaly, and regulations and permit requirements. (MHR)

  14. Honey Lake Geothermal Project, Lassen County, California (United States)


    The drilling, completion, and testing of deep well WEN-2 for a hybrid electric power project which will use the area's moderate temperature geothermal fluids and locally procured wood fuel is reported. The project is located within the Wendel-Amedee Known Geothermal Resource Area.

  15. Relationshipe Between Self-potential Anomalies and Hydraulic Flow In A Geothermal System: Application To Cerro-prieto, Baja California (United States)

    Saracco, G.; Revil, A.; Pessel, M.

    The Cerro Prieto geothermal field is located in the alluvial plain of the Mexicali Valley, northern Baja California, Mexico, at about 35 km southeast of the city of Mexicali. The Cerro Prieto geothermal field is one of several high temperature water-dominated geothermal fields within the Salton Trough. We analyze here the self-potential distri- bution at the ground surface in order to determine the pattern of fluid flow in te sub- surface of this geothermal field. Various methods of analysis of self-potential anoma- lies are employed to reach this purpose. We use density probability tomography of monopolar and dipolar electrical sources and an Euler-type analysis. The hydraulic flow pattern found in this geothermal field is in agreement with that detemined from the heat flux inside the structure.

  16. California low-temperature geothermal resources update: 1993

    Energy Technology Data Exchange (ETDEWEB)

    Youngs, L.G.


    The US Department of Energy -- Geothermal Division (DOE/GD) recently sponsored the Low-Temperature Geothermal Resources and Technology Transfer Program to bring the inventory of the nation`s low- and moderate-temperature geothermal resources up to date and to encourage development of the resources. The Oregon Institute of Technology, Geo-Heat Center (OIT/GHC) and the University of Utah Research Institute (UURI) established subcontracts and coordinated the project with the state resource teams from the western states that participated in the program. The California Department of Conservation, Division of Mines and Geology (DMG) entered into contract numbered 1092--023(R) with the OIT/GHC to provide the California data for the program. This report is submitted in fulfillment of that contract.

  17. Potential of low-temperature geothermal resources in northern California. Report No. TR13

    Energy Technology Data Exchange (ETDEWEB)

    Hannah, J.L.


    Economically feasible uses for geothermal heat at temperatures too low for conventional electrical power generation at present are delineated. Several geothermal resource areas in northern California that have development potential are described, and applications of the heat found in each area are suggested. Plates are included of the following field study areas: the east side of the Sierra-Cascade Range north of Bishop, and the northern Coast Range from San Francisco Bay to Clear Lake. The counties included in the study area are Mo doc, Lassen, Sierra, Plumas, Placer, Alpine, Mono, Mendocino, Lake, and Sonoma. (LBS)

  18. Age and thermal history of the Geysers plutonic complex (felsite unit), Geysers geothermal field, California: A 40Ar/39Ar and U-Pb study (United States)

    Dalrymple, G.B.; Grove, M.; Lovera, O.M.; Harrison, T.M.; Hulen, J.B.; Lanphere, M.A.


    Sixty-nine ion microprobe spot analyses of zircons from four granite samples from the plutonic complex that underlies the Geysers geothermal field yield 207Pb/206Pb vs. 238U/206Pb concordia ages ranging from 1.13 ?? 0.04 Ma to 1.25 ?? 0.04 (1??) Ma. The weighted mean of the U/Pb model ages is 1.18 ?? 0.03 Ma. The U-Pb ages coincide closely with 40Ar/39Ar age spectrum plateau and 'terminal' ages from coexisting K-feldspars and with the eruption ages of overlying volcanic rocks. The data indicate that the granite crystallized at 1.18 Ma and had cooled below 350??C by ~0.9-1.0 Ma. Interpretation of the feldspar 40Ar/39Ar age data using multi-diffusion domain theory indicates that post-emplacement rapid cooling was succeeded either by slower cooling from 350??to 300??C between 1.0 and 0.4 Ma or transitory reheating to 300-350??C at about 0.4-0.6 Ma. Subsequent rapid cooling to below 260??C between 0.4 and 0.2 Ma is in agreement with previous proposals that vapor-dominated conditions were initiated within the hydrothermal system at this time. Heat flow calculations constrained with K-feldspar thermal histories and the present elevated regional heat flow anomaly demonstrate that appreciable heat input from sources external to the known Geysers plutonic complex is required to maintain the geothermal system. This requirement is satisfied by either a large, underlying, convecting magma chamber (now solidified) emplaced at 1.2 Ma or episodic intrusion of smaller bodies from 1.2 to 0.6 Ma.

  19. Klamath Falls geothermal field, Oregon

    Energy Technology Data Exchange (ETDEWEB)

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


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

  20. Geothermal Field Development in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, Hector Alonso


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

  1. Cerro Prieto geothermal field: exploration during exploitation

    Energy Technology Data Exchange (ETDEWEB)


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

  2. Geothermal regimes of the Clearlake region, northern California

    Energy Technology Data Exchange (ETDEWEB)

    Amador, M. [ed.; Burns, K.L.; Potter, R.M.


    The first commercial production of power from geothermal energy, at The Geysers steamfield in northern California in June 1960, was a triumph for the geothermal exploration industry. Before and since, there has been a search for further sources of commercial geothermal power in The Geysers--Clear Lake geothermal area surrounding The Geysers. As with all exploration programs, these were driven by models. The models in this case were of geothermal regimes, that is, the geometric distribution of temperature and permeability at depth, and estimates of the physical conditions in subsurface fluids. Studies in microseismicity and heat flow, did yield geophysical information relevant to active geothermal systems. Studies in stable-element geochemistry found hiatuses or divides at the Stoney Creek Fault and at the Collayomi Fault. In the region between the two faults, early speculation as to the presence of steamfields was disproved from the geochemical data, and the potential existence of hot-water systems was predicted. Studies in isotope geochemistry found the region was characterized by an isotope mixing trend. The combined geochemical data have negative implications for the existence of extensive hydrothermal systems and imply that fluids of deep origin are confined to small, localized systems adjacent to faults that act as conduits. There are also shallow hot-water aquifers. Outside fault-localized systems and hot-water aquifers, the area is an expanse of impermeable rock. The extraction of energy from the impermeable rock will require the development and application of new methods of reservoir creation and heat extraction such as hot dry rock technology.

  3. Tongonan geothermal field Leyte, Philippines. Report on exploration and development

    Energy Technology Data Exchange (ETDEWEB)


    Geothermal exploration and development in the Philippines are reviewed. The geology, geophysics, and geochemistry of the Tongonan geothermal field are described. The well drilling, power development, and plans for a 112 MW power plant are included. (MHR)

  4. California: basic data for thermal springs and wells as recorded in GEOTHERM. Part A

    Energy Technology Data Exchange (ETDEWEB)

    Bliss, J.D.


    This GEOTHERM sample file contains 1535 records for California. Three computer-generated indexes give one line summaries of each GEOTHERM record. Each index is sorted by different variables to assist in locating geothermal records describing specific sites. 7 refs. (ACR)

  5. Geothermal energy: opportunities for California commerce. Phase I report

    Energy Technology Data Exchange (ETDEWEB)

    Longyear, A.B. (ed.)


    The potential geothermal direct-use energy market and its application to projects in California are assessed. Project identification effort is to be focused on those that have the highest probability for near-term successful commercial operations. Near-term herein means 2 to 5 years for project implementation. Phase I has been focused on defining and assessing: (1) the geothermal direct-use resources that are suitable for near-term utilization; and (2) the generic applications (municipal heating districts, horticultural greenhouse firms, laundries, etc.) that are suitable for near-term projects. Five economic development regions in the state, containing recognized geothermal direct-use resources, have been defined. Thirty-eight direct use resources have been evaluated in these regions. After assessment against pre-selected criteria, twenty-seven have been rated with a priority of I, II or III, thereby qualifying them for further marketing effort. The five areas with a priority of I are summarized. These areas have no perceived impediments to near-term development. Twenty-nine generic categories of applications were assessed against previously selected criteria to determine their near term potential for direct use of geothermal fluids. Some twenty industry, commercial and institutional application categories were rated with a priority of I, II or III and warrant further marketing efforts. The seven categories with a priority of I are listed. These categories were found to have the least impediments to near-term application projects.

  6. Geothermal emissions data base: Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, S.R. (comp.)


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

  7. Geoelectromagnetic and geothermic investigations in the Ihlara Valley geothermal field (United States)

    İlkişik, O. Metin; Gürer, Aysan; Tokgöz, Tuǧrul; Kaya, Cemal


    The Ihlara Valley is situated within a volcanic arc that is formed by the collision of the eastern Mediterranean plate system with the Anatolian plate. In this study we will present data from a reservoir monitoring project over the Ihlara-Ziga geothermal field, located 22 km east of Aksaray, in central Anatolia. Although identified geothermal resources in the Ihlara Valley are modest, substantial undiscovered fields have been inferred primarily from the volcanic and tectonic setting but also from the high regional heat flow (150-200 mWm -2) on the Kirşehir Massif. In 1988 and 1990, geoelectromagnetic surveys were undertaken by MTA-Ankara to confirm the presence of a relatively shallow (≈ 0.5-1 km), hydrothermally caused conductive layer or zone. CSAMT and Schlumberger resistivity data show good correspondence with each other, and 2-D geoelectric models are also in harmony with geologic data and gravity anomalies. The depth of the resistive basement, which is interpreted as Paleozoic limestone, is 200-250 m in the western part and increases eastward (≈ 600-750 m). This may imply N-S-oriented normal faulting within the survey area. The parameters of the top layer are a resistivity of 25 to 95 ohm m and a thickness of between 100 and 250 m. The thickness of the conductive tuffs between the top layer and the basement, whose resistivity is about 4-5 o hmm, also increases eastward (from 100 to 450 m). The apparent resistivity maps for the frequencies between 32 and 2 Hz reveal a localized low resistivity anomaly to the east of Belisirma.

  8. Reservoir assessment of The Geysers Geothermal field

    Energy Technology Data Exchange (ETDEWEB)

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


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

  9. Reconnaissance of geothermal resources of Los Angeles County, California

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, C.T.


    Thermal waters produced from large oil fields are currently the most important geothermal resources in Los Angeles County. Otherwise, the County does not appear to have any large, near-surface geothermal resources. The oil fields produce thermal water because of both the moderate depths of production and normal to above-normal geothermal gradients. Gradients are about 3.0-3.5/sup 0/C/100 meters in the Ventura Basin and range from that up to about 5.5-6.0/sup 0/C/100 meters in the Los Angeles Basin. The hottest fields in the County are west of the Newport-Inglewood Structural Zone. The Los Angeles Basin has substantially more potential for uses of heat from oil fields than does the Ventura Basin because of its large fields and dense urban development. Produced fluid temperatures there range from ambient air to boiling, but most are in the 100-150/sup 0/F range. Daily water production ranges from only a few barrels at some fields to over a million barrels at Wilmington Oil Field; nearly all fields produce less than 50,000 barrels/day. Water salinity generally ranges from about 15,000-35,000 mg/liter NaCl. Fields with the most promise as sources of heat for outside applications are Wilmington, Torrance, Venice Beach, and Lawndale. The centralized treatment facilities are the most favorable sites for extraction of heat within the oil fields. Because of the poor water quality heat exchangers will likely be required rather than direct circulation of the field water to users. The best sites for applications are commercial-industrial areas and possibly institutional structures occupied by large numbers of people.

  10. Optimization of injection scheduling in geothermal fields

    Energy Technology Data Exchange (ETDEWEB)

    Lovekin, J.


    This study discusses the application of algorithms developed in Operations Research to the optimization of brine reinjection in geothermal fields. The injection optimization problem is broken into two sub-problems: (1) choosing a configuration of injectors from an existing set of wells, and (2) allocating a total specified injection rate among chosen injectors. The allocation problem is solved first. The reservoir is idealized as a network of channels or arcs directly connecting each pair of wells in the field. Each arc in the network is considered to have some potential for thermal breakthrough. This potential is quantified by an arc-specific break-through index, b/sub ij/, based on user-specified parameters from tracer tests, field geometry, and operating considerations. The sum of b/sub ij/-values for all arcs is defined as the fieldwide breakthrough index, B. Injection is optimized by choosing injection wells and rates so as to minimize B subject to constraints on the number of injectors and the total amount of fluid to be produced and reinjected. The study presents four computer programs which employ linear or quadratic programming to solve the allocation problem. In addition, a program is presented which solves the injector configuration problem by a combination of enumeration and quadratic programming. The use of the various programs is demonstrated with reference both to hypothetical data and an actual data set from the Wairakei Geothermal Field in New Zealand.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  12. Significant Problems in Geothermal Development in California, Final Report on Four Workshops, December 1978 - March 1979

    Energy Technology Data Exchange (ETDEWEB)



    From November 1978 through March 1979 the California Geothermal Resources Board held four workshops on the following aspects of geothermal development in California: County Planning for Geothermal Development; Federal Leasing and Environmental Review Procedures; Transmission Corridor Planning; and Direct Heat Utilization. One of the objectives of the workshops was to increase the number of people aware of geothermal resources and their uses. This report is divided into two parts. Part 1 provides summaries of all the key information discussed in the workshops. For those people who were not able to attend, this part of the report provides you with a capsule version of the workshop sessions. Part 2 focuses on the key issues raised at the workshops which need to be acted upon to expedite geothermal resource development that is acceptable to local government and environmentally prudent. For the purpose of continuity, similar Geothermal Resources Task Force recommendations are identified.

  13. Geothermal Gases--Community Experiences, Perceptions, and Exposures in Northern California. (United States)

    Chiu, Cindy H; Lozier, Matthew J; Bayleyegn, Tesfaye; Tait, Karen; Barreau, Tracy; Copan, Lori; Roisman, Rachel; Jackson, Rebecca; Smorodinsky, Svetlana; Kreutzer, Richard A; Yip, Fuyuen; Wolkin, Amy


    Lake County, California, is in a high geothermal-activity area. Over the past 30 years, the city of Clearlake has reported health effects and building evacuations related to geothermal venting. Previous investigations in Clearlake revealed hydrogen sulfide at levels known to cause health effects and methane at levels that can cause explosion risks. The authors conducted an investigation in multiple cities and towns in Lake County to understand better the risk of geothermal venting to the community. They conducted household surveys and outdoor air sampling of hydrogen sulfide and methane and found community members were aware of geothermal venting and some expressed concerns. The authors did not, however, find hydrogen sulfide above the California Environmental Protection Agency air quality standard of 30 parts per billion over one hour or methane above explosive thresholds. The authors recommend improving risk communication, continuing to monitor geothermal gas effects on the community, and using community reports and complaints to monitor and document geothermal venting incidents.

  14. Program planner's guide to geothermal development in California

    Energy Technology Data Exchange (ETDEWEB)

    Yen, W.W.S.; Chambers, D.M.; Elliott, J.F.; Whittier, J.P.; Schnoor, J.J.; Blachman, S.


    The resource base, status of geothermal development activities, and the state's energy flow are summarized. The present and projected geothermal share of the energy market is discussed. The public and private sector initiatives supporting geothermal development in California are described. These include legislation to provide economic incentives, streamline regulation, and provide planning assistance to local communities. Private sector investment, research, and development activities are also described. The appendices provide a ready reference of financial incentives. (MHR)

  15. Pilot fruit drier for Los Azufres geothermal field, Michoacan, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lund, J.W.


    Comision Federal de Electricidad (CFE) has a Division in charge of the exploration of a geothermal reservoir located in Los Azufres, State of Michoacan. At present, CFE is only using the steam of the wells and rejecting the hot water that comes off associated with the steam. Based on a trip to the Los Azufres geothermal field in December of 1992, a design for a pilot geothermal fruit drier was undertaken for CFE. The details of the geothermal field and the local fruit production are detailed.

  16. Report of the State Geothermal Resources Task Force, State of California

    Energy Technology Data Exchange (ETDEWEB)

    Warburg, Judith; Kirkham, Bill; Hannon, Theodore


    The State Geothermal Resources Task Force has investigated the status of geothermal resources and development in California and in this report offers recommendations for overcoming obstacles facing increased utilization of this significant natural resource. For the most part, these recommendations are short-term solutions to immediate problems and would not radically change the roles of governmental agencies currently regulating geothermal development. The Task Force concludes that geothermal operations have been hindered by the lack of a statewide policy on geothermal development. This has resulted in instances where industry has been forced to comply with conflicting governmental policies toward geothermal energy development and environmental protection. The Task Force therefore recommends legislation establishing a statewide policy to encourage geothermal development consistent with environmental quality standards. In addition to geothermal resources suitable for the production of electrical power, California has extensive undeveloped hot water reservoirs suitable for direct thermal applications. The Energy Resources Conservation and Development Commission and the US Geological Survey have concluded that these resources, if developed, could make a significant contribution to satisfying California's energy needs. The Task Force therefore recommends establishing a statewide policy to encourage the use of non-electric hot water geothermal resources for commercial and non-commercial uses where the development is consistent with environmental quality concerns.

  17. Distribution of high-temperature (>150 °C) geothermal resources in California (United States)

    Sass, John H.; Priest, Susan S.


    California contains, by far, the greatest geothermal generating capacity in the United States, and with the possible exception of Alaska, the greatest potential for the development of additional resources. California has nearly 2/3 of the US geothermal electrical installed capacity of over 3,000 MW. Depending on assumptions regarding reservoir characteristics and future market conditions, additional resources of between 2,000 and 10,000 MWe might be developed (see e.g., Muffler, 1979).

  18. Analysis of requirements for accelerating the development of geothermal energy resources in California (United States)

    Fredrickson, C. D.


    Various resource data are presented showing that geothermal energy has the potential of satisfying a singificant part of California's increasing energy needs. General factors slowing the development of geothermal energy in California are discussed and required actions to accelerate its progress are presented. Finally, scenarios for developing the most promising prospects in the state directed at timely on-line power are given. Specific actions required to realize each of these individual scenarios are identified.

  19. Exploration and development of the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

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


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

  20. Sources of subsidence at the Salton Sea Geothermal Field (United States)

    Barbour, Andrew J.; Evans, Eileen; Hickman, Stephen H.; Eneva, Mariana


    At the Salton Sea Geothermal Field (SSGF) in Southern California, surface deformation associated with geologic processes including sediment compaction, tectonic strain, and fault slip may be augmented by energy production activities. Separating the relative contributions from natural and anthropogenic sources is especially important at the SSGF, which sits at the apex of a complex tectonic transition zone connecting the southern San Andreas Fault with the Imperial Fault; but this has been a challenging task so far. Here we analyze vertical surface velocities obtained from the persistent scatterer InSAR method and find that two of the largest subsidence anomalies can be represented by a set of volumetric strain nuclei at depths comparable to geothermal well completion zones. In contrast, the rates needed to achieve an adequate fit to the magnitudes of subsidence are almost an order of magnitude greater than rates reported for annual changes in aggregate net-production volume, suggesting that the physical mechanism responsible for subsidence at the SSGF is a complicated interplay between natural and anthropogenic sources.

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  2. Geothermal Fields on the Volcanic Axis of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Mercado, S.; Gonzalez, A.


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

  3. Symposium in the field of geothermal energy

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, Miguel; Mock, John E.


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

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

    Energy Technology Data Exchange (ETDEWEB)

    Layman Energy Associates, Inc.


    With financial support from the U.S. Department of Energy (DOE), Layman Energy Associates, Inc. (LEA) has completed a program of geothermal exploration at the Truckhaven area in Imperial County, California. The exploratory work conducted by LEA included the following activities: compilation of public domain resource data (wells, seismic data, geologic maps); detailed field geologic mapping at the project site; acquisition and interpretation of remote sensing imagery such as aerial and satellite photographs; acquisition, quality control and interpretation of gravity data; and acquisition, quality control and interpretation of resistivity data using state of the art magnetotelluric (MT) methods. The results of this exploratory program have allowed LEA to develop a structural and hydrologic interpretation of the Truckhaven geothermal resource which can be used to guide subsequent exploratory drilling and resource development. Of primary significance, is the identification of an 8 kilometer-long, WNW-trending zone of low resistivity associated with geothermal activity in nearby wells. The long axis of this low resistivity zone is inferred to mark a zone of faulting which likely provides the primary control on the distribution of geothermal resources in the Truckhaven area. Abundant cross-faults cutting the main WNW-trending zone in its western half may indicate elevated fracture permeability in this region, possibly associated with thermal upwelling and higher resource temperatures. Regional groundwater flow is inferred to push thermal fluids from west to east along the trend of the main low resistivity zone, with resource temperatures likely declining from west to east away from the inferred upwelling zone. Resistivity mapping and well data have also shown that within the WNW-trending low resistivity zone, the thickness of the Plio-Pleistocene sedimentary section above granite basement ranges from 1,900–2,600 meters. Well data indicates the lower part of this

  5. Resource assessment of low- and moderate-temperature geothermal waters in Calistoga, Napa County, California. Report of the second year, 1979-1980

    Energy Technology Data Exchange (ETDEWEB)

    Youngs, L.G.; Bacon, C.F.; Chapman, R.H.; Chase, G.W.; Higgins, C.T.; Majmundar, H.H.; Taylor, G.C.


    Phase I studies included updating and completing the USGS GEOTHERM file for California and compiling all data needed for a California Geothermal Resources Map. Phase II studies included a program to assess the geothermal resource at Calistoga, Napa County, California. The Calistoga effort was comprised of a series of studies involving different disciplines, including geologic, hydrologic, geochemical and geophysical studies.

  6. Description of Imperial Valley, California for the assessment of impacts of geothermal energy development

    Energy Technology Data Exchange (ETDEWEB)

    Layton, D.; Ermak, D.


    Impending geothermal development in the Imperial Valley of California has raised concern over the possible impacts of such development. As an initial step in impact assessment of geothermal projects, relevant features of the valley's physical and human environments are described. Particular attention is placed on features that may either influence development or be affected by it. Major areas of consideration include the valley's physical resources (i.e., land, air, water, and biological resources), economic, fiscal, and social characteristics of Imperial County, and geothermal laws.

  7. Geotechnical environmental aspects of geothermal power generation at Herber, Imperial Valley, California

    Energy Technology Data Exchange (ETDEWEB)


    The feasibility of constructing a 25-50 MWe geothermal power plant using low salinity hydrothermal fluid as the energy source was assessed. Here, the geotechnical aspects of geothermal power generation and their relationship to environmental impacts in the Imperial Valley of California were investigated. Geology, geophysics, hydrogeology, seismicity and subsidence are discussed in terms of the availability of data, state-of-the-art analytical techniques, historical and technical background and interpretation of current data. Estimates of the impact of these geotechnical factors on the environment in the Imperial Valley, if geothermal development proceeds, are discussed.

  8. Geothermal development of the Salton Trough, California and Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, T.D.; Howard, J.H.; Lande, D.P. (eds.)


    A geological description is given of the Salton Trought followed by a chronological history of attempts to exploit the area's geothermal resources. In addition, detailed descriptions are given of all ongoing geothermal projects in the area and the organizations conducting them.

  9. Resource assessment of low- and moderate-temperature geothermal waters in Calistoga, Napa County, California. Report of the second year, 1979 to 1980 of the US Department of Energy-California State-Coupled Program for reservoir assessment and confirmation

    Energy Technology Data Exchange (ETDEWEB)

    Youngs, L.G.; Bacon, C.F.; Chapman, R.H.; Chase, G.W.; Higgins, C.T.; Majmundar, H.H.; Taylor, G.C.


    Statewide assessment studies included updating and completing the USGS GEOTHERM File for California and compiling all data needed for a California Geothermal Resources Map. Site specific assessment studies included a program to assess the geothermal resource at Calistoga, Napa County, California. The Calistoga effort was comprised of a series of studies involving different disciplines, including geologic, hydrologic, geochemical and geophysical studies.

  10. Geothermal development and land use/energy planning by the State of California and its political subdivisions

    Energy Technology Data Exchange (ETDEWEB)


    California law contains several vehicles for the implementation of geothermal planning. These mechanisms and their impact are examined. First, at the State level upon the California Energy Commission and the Division of Oil and Gas in the Department of Conservation. After some background on county planning in California, the unique situation in the counties of greatest geothermal potential is presented: Imperial County and the four Geysers counties as well as their joint powers agency. Conclusions and recommendations are included. (MHR)

  11. An example of geothermal systems: Hidirlar Geothermal Field, Biga Peninsula, NW Turkey (United States)

    Ateş, Özkan; Zeki Tutkun, Salih; Baba, Alper; Woith, Heiko; Özden, Süha


    Biga Peninsula located at northwestern Anatolia on southern segment on the dextral North Anatolian Fault and has many important geothermal potential areas. There are known 14 geothermal system namely Tuzla, Kestanbol, Hıdırlar, Kırkgeçit, Kocabaşlar, Bardakçılar, Palamutoba, Akçakeçili, Küçükçetmi, Külcüler, Tepeköy, Çan, Topaklar and Etili. Among them, an important field is the Hıdırlar geothermal field, situated at the southeast of the Biga Peninsula. This field is in a tectonosedimentary basin and controlled by different trending faults. It has a potential usage about 87,7°C surface discharge temperature. Three thermal springs sampled in the Hıdırlar geothermal field. They have named as Spring, Drill and Uyuz. Their surface temperatures are Spring=77,5°C, Drill=57,7°C and Uyuz=53,6°C. According to the result of hydro-geochemical analysis and diagrams, thermal waters are generally Na-SO4 and Na-SO4-HCO3 water types. Assessments of chemical geothermometers applied to the thermal waters, suggest that reservoir temperatures are 90°C-163°C for Spring, 81°C-149°C for Drill and 83°C-161°C for Uyuz. Around Hıdırlar geothermal field, have been determined five different geological units. Lower-Middle Triassic aged Nilüfer Unit of Karakaya Complex is the basement unit. Late Oligocene aged Çakıroba granodiorite and Çan volcanic rocks overlie the basement metamorphic rocks with an unconformity. Neogene aged Örencik Formation, Quaternary aged slope washes and alluvium cover all older units with angular unconformity. Main structural trends have ENE-trending normal faults and they have been cutting by youngest NE-trending normal faults with a dextral strike-slip component. All thermal water springs are arranged on the NE-trending youngest faults. Both fault-slip data and joint measurements, mainly in granodiorites, show an active local extensional tectonic regime on southern segment of North Anatolian Fault. This local tectonic regime

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

    Energy Technology Data Exchange (ETDEWEB)


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

  13. Investigation of the heat source(s) of the Surprise Valley Geothermal System, Northern California (United States)

    Tanner, N.; Holt, C. D.; Hawkes, S.; McClain, J. S.; Safford, L.; Mink, L. L.; Rose, C.; Zierenberg, R. A.


    Concerns about environmental impacts and energy security have led to an increased interest in sustainable and renewable energy resources, including geothermal systems. It is essential to know the permeability structure and possible heat source(s) of a geothermal area in order to assess the capacity and extent of the potential resource. We have undertaken geophysical surveys at the Surprise Valley Hot Springs in Cedarville, California to characterize essential parameters related to a fault-controlled geothermal system. At present, the heat source(s) for the system are unknown. Igneous bodies in the area are likely too old to have retained enough heat to supply the system, so it is probable that fracture networks provide heat from some deeper or more distributed heat sources. However, the fracture system and permeability structure remain enigmatic. The goal of our research is to identify the pathways for fluid transport within the Surprise Valley geothermal system using a combination of geophysical methods including active seismic surveys and short- and long-period magnetotelluric (MT) surveys. We have collected 14 spreads, consisting of 24 geophones each, of active-source seismic data. We used a "Betsy Gun" source at 8 to 12 locations along each spread and have collected and analyzed about 2800 shot-receiver pairs. Seismic velocities reveal shallow lake sediments, as well as velocities consistent with porous basalts. The latter, with velocities of greater than 3.0 km/s, lie along strike with known hot springs and faulted and tilted basalt outcrops outside our field area. This suggests that basalts may provide a permeable pathway through impermeable lake deposits. We conducted short-period (10Hz-60kHz) MT measurements at 33 stations. Our short-period MT models indicate shallow resistive blocks (>100Ωm) with a thin cover of more conductive sediments ( 10Ωm) at the surface. Hot springs are located in gaps between resistive blocks and are connected to deeper low

  14. Vitrinite reflectance geothermometry and apparent heating duration in the Cerro Prieto geothermal field (United States)

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


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

  15. A database for The Geysers geothermal field

    Energy Technology Data Exchange (ETDEWEB)

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


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

  16. The Hydrogeochemistry of Qingshui Geothermal Field, Northeastern Taiwan. (United States)

    Yu-Wen, Chen; Cheng-Kuo, Lin; Wayne, Lin; Yu-Te, Chang; Pei-Shan, Hsieh


    The Qingshui geothermal field is located at the upstream valley of Lanyang Creek, northeastern Taiwan. It is renowned as a geothermal field. The previous studies demonstrated a higher geothermal gradient, 100oC/km warmer than a normal geotherm. However, Qingshui geothermal field has not been well developed due to the higher mining costs. In the recent years, the Taiwan government has been focusing on developing alternative and renewable energy and initiated a 10 year project, Nation Energy Program. This study is part of this project In general, it is very difficult to collect deep downhole samples without considerable change of hydro- and gas- chemistry of water under high temperature and pressure. A new sampling tool, GTF Sampler, was designed by the research team, Green Energy and Environment Laboratories, Industrial Technology Research Institute. This tool can simultaneously collect high quality geothermal water and gas sample and moreover, the sampling depth can reach up to 800 meters. Accordingly, a more accurate measurements can be conducted in the laboratory. In this study, 10 geothermal samples were collected and measured. The results demonstrate that geothermal water samples are characterized with Na(K)-HCO3 water type and located at the mature water area in Giggenbach Na-K-Mg diagram. Several geothermometers, including silica and cation geothermometry, were used to estimate potential temperature in the geothermal reservoir systems. In general, the geothermoters of Na-K and Na-K-Ca obtain reservoir temperatures between 120-190oC and 130-210oC, respectively, but the silica geothermometer indicates a lower reservoir temperature between 90 and 170oC. There is no big difference among them. It is worth to note that all calculated temperatures are lower than those of in-situ downhole measurements; therefore, more detailed and advanced researches would be needed for the inconsistency. To examine the argument about igneous heat source in the previous studies, rare

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

    Energy Technology Data Exchange (ETDEWEB)


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

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

    CERN Document Server

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


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

  19. Tridimensional gravity model of the Travale geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Toro, B.; Di Filippo, M. [Rome Univ. (Italy); Dini, I. [Ente Nazionale per l`Energia Elettrica, Pisa (Italy). Centro di Ricerca Geotermica; Bruschi, S.


    The paper discusses a tri dimensional gravity model of the Travale geothermal field (GR, Italy). The model was developed on the basis of stratigraphic data from wells existing in the area and from previous geophysical studies. The model, developed with a high level of detail, showed that the geothermal reservoir accommodates areas of lower density than the surrounding ones, corresponding to high productivity areas. This finding may be explained by the fact that, in the most productive areas, the reservoir has higher porosity or fracturing and houses vapor-phase fluids. (Authors). 5 refs., 9 figs.

  20. Temperature distribution in the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

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


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

  1. Deep geothermal processes acting on faults and solid tides in coastal Xinzhou geothermal field, Guangdong, China (United States)

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


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

  2. Tar Creek study, Sargent oil field, Santa Clara County, California (United States)

    Wagner, David L.; Fedasko, Bill; Carnahan, J.R.; Brunetti, Ross; Magoon, Leslie B.; Lillis, Paul G.; Lorenson, T.D.; Stanley, Richard G.


    Field work in the Tar Creek area of Sargent oil field was performed June 26 to 28, 2000. The Santa Clara County study area is located in Sections, 30, 31, and 32, Township 11 South, Range 4 East, M.D.B&M; and in Sections 25 and 36, Township 11 South, Range 3 East, M.D.B.&M., north and south of Tar Creek, west of Highway 101. The work was a cooperative effort of the California Department of Conservation's Division of Oil, Gas, and Geothermal Resources (DOGGR), California Geological Survey (CGS), and the United States Geological Survey (USGS). The purpose of the project was to map the stratigraphy and geologic structure (David Wagner, CGS); sample oil for age dating (Les Magoon, USGS); and search for undocumented wells plus conduct a GPS survey of the area (Bill Fedasko, J.P. Carnahan, and Ross Brunetti, DOGGR)

  3. Geothermal direct-heat study: Imperial County, California

    Energy Technology Data Exchange (ETDEWEB)


    Potential applications of geothermal energy which would be compatible with the agricultural activities in the county were identified and a plan to attract potential users to the area was developed. The intent of the first effort was to identify general classifications of industries which could utilize geothermal heat in production processes. Two levels of analyses were utilized for this effort. Initially, activities relying on previously developed engineering and industrial concepts were investigated to determine capital costs, employment, and potential energy savings. Second, innovative concepts not yet fully developed were investigated to determine their potential applicability to the agricultural base of the county. These investigations indicated that the major potential applications of geothermal heat would involve industries related to food processing or other direct agriculture-related uses of raw materials produced or imported to the county. An implementation plan which can be utilized by the county to market direct heat applications was developed. A socioeconomics analysis examined the potential effects on the county from development of direct heat projects. The county's planning and permitting requirements for dirct heat projects were also examined.

  4. A Reservoir Assessment of the Geysers Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

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


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

  5. Honey Lake hybrid geothermal wood residue power plant, Lassen County, California

    Energy Technology Data Exchange (ETDEWEB)


    The feasibility of a proposed 50 MW (gross) electric power project located near Wendel, California about 25 miles east of Susanville was studied. The project would be the first commercial power plant to combine the use of geothermal energy and wood fuel for power production. Wood fuel consisting primarily of various forms of forest management residues would be processed and partially dehydrated with geothermal energy prior to combustion. Geothermal energy would also be used for boiler feedwater heating and combustion air preheating. The study defines the range of site-specific benefits and economics of using wood fuel and moderate temperature geothermal energy, both of which are abundant and often located in proximity at many locations in the western United States. The study results document conclusively that overall project economics can be very favorable and that in addition to providing an important source of electric power, many benefits to forest land managers, local communities, project developers and the state of the environment can be derived from the combined use of moderate temperature geothermal energy and wood fuel.

  6. Preliminary design manual for a Geothermal Demonstration Plant at Heber, California

    Energy Technology Data Exchange (ETDEWEB)

    Holt, B.; Ghormley, E.L.


    A preliminary design of a 50 MWe Geothermal Demonstration Plant for Heber, California is presented. A site description, design basis, process design, trade-off studies to optimize plant operations, and an economic analysis of the plant are included. The plant design provides flow diagrams and equipment specifications for the energy conversion system, the cooling water system, the plant and instrument air system, the flare system, the firewater system, the electrical system, the piping system, instruments and controls, and buildings and structures.

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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)

  8. Differential Absorption Lidar Mapping of Atmospheric Atomic Mercury in Italian Geothermal Fields (United States)

    Edner, H.; Ragnarson, P.; Svanberg, S.; Wallinder, E.; de Liso, A.; Ferrara, R.; Maserti, B. E.


    Results from extensive lidar measurements on atmospheric atomic mercury in Italian geothermal fields are reported. A mobile differential absorption lidar system operating on the 254-nm mercury resonance line with a measuring range of about 1 km was used in mineralized as well as nonmineralized areas. Measurements were performed at geothermal power stations and in an unexploited field with natural surface geothermic manifestations. Atomic mercury concentrations ranging from 2 to 1000 ng/m3 were mapped. The high Italian geothermal mercury concentrations are in strong contrast to the recent lidar finding of the absence of atomic mercury in Icelandic geothermal fields.

  9. Final Report: Natural State Models of The Geysers Geothermal System, Sonoma County, California

    Energy Technology Data Exchange (ETDEWEB)

    T. H. Brikowski; D. L. Norton; D. D. Blackwell


    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.

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

    Energy Technology Data Exchange (ETDEWEB)


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  12. The Geysers Geothermal Field Update1990/2010

    Energy Technology Data Exchange (ETDEWEB)

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


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

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

    Directory of Open Access Journals (Sweden)

    D. F. Yudiantoro


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

    Massey, B.L.


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

  16. Geotechnical Environmental Aspects of Geothermal Power Generation at Heber, Imperial Valley, California. Topical report 1

    Energy Technology Data Exchange (ETDEWEB)



    This report presents a portion of the results from a one-year feasibility study sponsored by the Electric Power Research Institute (EPRI) to assess the feasibility of constructing a 25-50 MWe geothermal power plant using low salinity hydrothermal fluid as the energy source. The impact of power generation from hydrothermal resources on subsurface water flow, seismicity and subsidence are of acute interest in the determination of the environmental acceptance of geothermal energy. At the same time, the experience and data bases in these areas are very limited. The objective of the project was to assess the technical, geotechnical, environmental and economic feasibility of producing electricity from hydrothermal resources like those known to exist in the US. The objective of this part of the study was to investigate the geotechnical aspects of geothermal power generation and their relationship to environmental impacts in the Imperial Valley of California. This report discusses geology, geophysics, hydrogeology, seismicity and subsidence in terms of the availability of data, state-of-the-art analytical techniques, historical and technical background and interpretation of current data. it also discusses estimates of the impact of these geotechnical factors on the environment in the Imperial Valley, if geothermal development proceeds.

  17. Relationships among seismic velocity, metamorphism, and seismic and aseismic fault slip in the Salton Sea Geothermal Field region (United States)

    McGuire, Jeffrey J.; Lohman, Rowena B.; Catchings, Rufus D.; Rymer, Michael J.; Goldman, Mark R.


    The Salton Sea Geothermal Field is one of the most geothermally and seismically active areas in California and presents an opportunity to study the effect of high-temperature metamorphism on the properties of seismogenic faults. The area includes numerous active tectonic faults that have recently been imaged with active source seismic reflection and refraction. We utilize the active source surveys, along with the abundant microseismicity data from a dense borehole seismic network, to image the 3-D variations in seismic velocity in the upper 5 km of the crust. There are strong velocity variations, up to ~30%, that correlate spatially with the distribution of shallow heat flow patterns. The combination of hydrothermal circulation and high-temperature contact metamorphism has significantly altered the shallow sandstone sedimentary layers within the geothermal field to denser, more feldspathic, rock with higher P wave velocity, as is seen in the numerous exploration wells within the field. This alteration appears to have a first-order effect on the frictional stability of shallow faults. In 2005, a large earthquake swarm and deformation event occurred. Analysis of interferometric synthetic aperture radar data and earthquake relocations indicates that the shallow aseismic fault creep that occurred in 2005 was localized on the Kalin fault system that lies just outside the region of high-temperature metamorphism. In contrast, the earthquake swarm, which includes all of the M > 4 earthquakes to have occurred within the Salton Sea Geothermal Field in the last 15 years, ruptured the Main Central Fault (MCF) system that is localized in the heart of the geothermal anomaly. The background microseismicity induced by the geothermal operations is also concentrated in the high-temperature regions in the vicinity of operational wells. However, while this microseismicity occurs over a few kilometer scale region, much of it is clustered in earthquake swarms that last from

  18. Strategies and Perceptions of Students' Field Note-Taking Skills: Insights from a Geothermal Field Lesson (United States)

    Dohaney, Jacqueline; Brogt, Erik; Kennedy, Ben


    Field note-taking skills are fundamental in the geosciences but are rarely explicitly taught. In a mixed-method study of an introductory geothermal field lesson, we characterize the content and perceptions of students' note-taking skills to derive the strategies that students use in the field. We collected several data sets: observations of the…

  19. Study of the influential leaders, power structure, community decisions, and geothermal energy development in Imperial County, California

    Energy Technology Data Exchange (ETDEWEB)

    Butler, E.W.; Hall, C.H.; Pick, J.B.


    The economy of Imperial County, California, is now dominated by agriculture, but economic studies indicate that the emerging geothermal sector could grow to a size comparable to that of agriculture. The purpose of this study is to discover the kind of power structure operating in Imperial County, the influential leaders, the source of their power, their probable reactions to geothermal development, and the possible effects geothermal development will have on the power structure. Several social science research methods are used to identify the influential leaders and to describe the power structure in Imperial County. An analysis of the opinions of leadership and the public shows the likely response to geothermal development. The power structure analysis, combined with forecasts of the economic effects of geothermal development, indicates the ways in which the power structure itself may change.

  20. Investigation of Low-Temperature Geothermal Resources in the Sonoma Valley Area, California

    Energy Technology Data Exchange (ETDEWEB)

    Youngs, Leslie G.; Chapman, Rodger H.; Chase, Gordon W.; Bezore, Stephen P.; Majmundar, Hasu H.


    The Sonoma Valley area contains low-temperature geothermal resources (20 C {le} T {le} 90 C) having the potential for useful development. Sonoma Valley residents, local governments and institutions, private developers, and manufacturers may be able to utilize the geothermal resources as an alternate energy source. Historically, there have been at least six geothermal spring areas developed in the Sonoma Valley. Four of these (Boyes Hot Springs, Fetter's Hot Springs, Agua Caliente Springs, and the Sonoma State Hospital warm spring) lie on a linear trend extending northwestward from the City of Sonoma. Detailed geophysical surveys delineated a major fault trace along the east side of the Sonoma Valley in association with the historic geothermal areas. Other fault traces were also delineated revealing a general northwest-trending structural faulting fabric underlying the valley. Water wells located near the ''east side'' fault have relatively high boron concentrations. Geochemical evidence may suggest the ''east side'' fault presents a barrier to lateral fluid migration but is a conduit for ascending fluids. Fifteen of the twenty-nine geothermal wells or springs located from literature research or field surveys are located along or east of this major fault in a 10 km (6.2 miles) long, narrow zone. The highest recorded water temperature in the valley appears to be 62.7 C (145 F) at 137.2 meters (450 feet) in a well at Boyes Hot Springs. This is consistent with the geothermal reservoir temperature range of 52-77 C (126-171 F) indicated by geothermometry calculations performed on data from wells in the area. Interpretation of data indicates a low-temperature geothermal fluid upwelling or ''plume'', along the ''east side'' fault with subsequent migration into permeable aquifers predominantly within volcanic strata. It is quite likely other geothermal fluid &apos

  1. Discovering new events beyond the catalogue—application of empirical matched field processing to Salton Sea geothermal field seismicity (United States)

    Wang, Jingbo; Templeton, Dennise C.; Harris, David B.


    Using empirical matched field processing (MFP), we compare 4 yr of continuous seismic data to a set of 195 master templates from within an active geothermal field and identify over 140 per cent more events than were identified using traditional detection and location techniques alone. In managed underground reservoirs, a substantial fraction of seismic events can be excluded from the official catalogue due to an inability to clearly identify seismic-phase onsets. Empirical MFP can improve the effectiveness of current seismic detection and location methodologies by using conventionally located events with higher signal-to-noise ratios as master events to define wavefield templates that could then be used to map normally discarded indistinct seismicity. Since MFP does not require picking, it can be carried out automatically and rapidly once suitable templates are defined. In this application, we extend MFP by constructing local-distance empirical master templates using Southern California Earthquake Data Center archived waveform data of events originating within the Salton Sea Geothermal Field. We compare the empirical templates to continuous seismic data collected between 1 January 2008 and 31 December 2011. The empirical MFP method successfully identifies 6249 additional events, while the original catalogue reported 4352 events. The majority of these new events are lower-magnitude events with magnitudes between M0.2-M0.8. The increased spatial-temporal resolution of the microseismicity map within the geothermal field illustrates how empirical MFP, when combined with conventional methods, can significantly improve seismic network detection capabilities, which can aid in long-term sustainability and monitoring of managed underground reservoirs.

  2. Numerical investigation of the efficiency of emission reduction and heat extraction in a sedimentary geothermal reservoir: a case study of the Daming geothermal field in China. (United States)

    Guo, Xuyang; Song, Hongqing; Killough, John; Du, Li; Sun, Pengguang


    The utilization of geothermal energy is clean and has great potential worldwide, and it is important to utilize geothermal energy in a sustainable manner. Mathematical modeling studies of geothermal reservoirs are important as they evaluate and quantify the complex multi-physical effects in geothermal reservoirs. However, previous modeling efforts lack the study focusing on the emission reduction efficiency and the deformation at geothermal wellbores caused by geothermal water extraction/circulation. Emission efficiency is rather relevant in geothermal projects introduced in areas characterized by elevated air pollution where the utilization of geothermal energy is as an alternative to burning fossil fuels. Deformation at geothermal wellbores is also relevant as significant deformation caused by water extraction can lead to geothermal wellbore instability and can consequently decrease the effectiveness of the heat extraction process in geothermal wells. In this study, the efficiency of emission reduction and heat extraction in a sedimentary geothermal reservoir in Daming County, China, are numerically investigated based on a coupled multi-physical model. Relationships between the efficiency of emission reduction and heat extraction, deformation at geothermal well locations, and geothermal field parameters including well spacing, heat production rate, re-injection temperature, rock stiffness, and geothermal well placement patterns are analyzed. Results show that, although large heat production rates and low re-injection temperatures can lead to decreased heat production in the last 8 years of heat extraction, they still improve the overall heat production capacity and emission reduction capacity. Also, the emission reduction capacity is positively correlated with the heat production capacity. Deformation at geothermal wellbore locations is alleviated by smaller well spacing, lower heat production rates, and smaller numbers of injectors in the well pattern, and by

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  4. The Ngatamariki Geothermal Field, NZ: Surface Manifestations - Past and Present

    Energy Technology Data Exchange (ETDEWEB)

    Brotheridge, J.M.A.; Browne, P.R.L.; Hochstein, M.P.


    The Ngatamariki geothermal field, located 7 km south of Orakeikorako, discharges dilute chloride-bicarbonate waters of almost neutral pH from springs mostly on the margins of the field. Rhyolite tuffs in the northwestern part of the field are weakly silicified, probably due to their having reacted with heated groundwaters. Sinter deposits are common at Ngatamariki but are mostly relict from former activity. In 1994, the natural heat loss from the field was 30 {+-} 5 MW{sub thermal}. There has been a shift of thermal activity southward over the past 60 years; the changes were recognized by comparing air photographs taken in 1941 and 1991. In 1948, a hydrothermal eruption deposited breccia around its crater, which is now occupied by a pool at 52.5 C. Another pool at 88 C, first noticed in 1993, deposits a mixture of silica and calcite.

  5. Interpretation of electromagnetic extra-low-frequency soundings in the Randsburg, California, Known Geothermal Resource Area

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, W.L.


    An electromagnetic (EM) controlled source survey was made during the period November 30, 1977, to December 13, 1977, in the Randsburg, California, Known Geothermal Resource Area (KGRA). The observed extra-low-frequency (ELF) data and least squares interpretation using a computer program developed by Anderson (1977) are summarized. The results are given in tabular form along with observed and calculated amplitude and phase plots. In addition, one vertical electrical sounding (VES) was obtained and a graphical solution is included via a Schlumberger inversion program developed by Zohdy (1973).

  6. California geothermal resource development environmental implications for ERCDC Environmental Analysis Office. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, J.A.


    The results of an analysis of the environmental implications for ERCDC Environmental Analysis Office (EAO) in relation to the development of California's geothermal resources are reported. While focusing primarily on environmental implications, particularly the natural, social, and economic elements, the report includes some ERCDC-wide policy and program considerations. The primary thrusts of the work have been in the development of an understanding of the interagency and intergovernmental environmental data and data-management roles and responsibilities and in the formulation of recommendations related thereto. Five appendices are included, one of which is a tax credit agreement between a power company and Skagit County, Washington. (JGB)

  7. Wine Valley Inn: A mineral water spa in Calistoga, California. Geothermal-energy-system conceptual design and economic feasibility

    Energy Technology Data Exchange (ETDEWEB)


    The purpose of this study is to determine the engineering and economic feasibility for utilizing geothermal energy for air conditioning and service water heating at the Wine Valley Inn, a mineral water spa in Calistoga, California. The study evaluates heating, ventilating, air conditioning and water heating systems suitable for direct heat geothermal application. Due to the excellent geothermal temperatures available at this site, the mechanics and economics of a geothermally powered chilled water cooling system are evaluated. The Wine Valley Inn has the resource potential to have one of the few totally geothermal powered air conditioning and water heating systems in the world. This total concept is completely developed. A water plan was prepared to determine the quantity of water required for fresh water well development based on the special requirements of the project. An economic evaluation of the system is included to justify the added capital investment needed to build the geothermally powered mineral spa. Energy payback calculations are presented. A thermal cascade system is proposed to direct the geothermal water through the energy system to first power the chiller, then the space heating system, domestic hot water, the two spas and finally to heat the swimming pool. The Energy Management strategy required to automatically control this cascade process using industrial quality micro-processor equipment is described. Energy Management controls are selected to keep equipment sizing at a minimum, pump only the amount of geothermal water needed and be self balancing.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  9. Geothermal systems (United States)

    Mohl, C.


    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.

  10. Hydrogeochemistry of the Simav geothermal field, western Anatolia, Turkey (United States)

    Gemici, Ünsal; Tarcan, Gültekin


    Thermal waters hosted by Menderes metamorphic rocks emerge along fault lineaments in the Simav geothermal area. Thermal springs and drilled wells are located in the Eynal, Çitgöl and Naşa locations, which are part of the Simav geothermal field. Studies were carried out to obtain the main chemical and physical characteristics of thermal waters. These waters are used for heating of residences and greenhouses and for balneological purposes. Bottom temperatures of the drilled wells reach 163°C with total dissolved solids around 2225 mg/kg. Surface temperatures of thermal springs vary between 51°C and 90°C. All the thermal waters belong to Na-HCO 3-SO 4 facies. The cold groundwaters are Ca-Mg-HCO 3 type. Dissolution of host rock and ion-exchange reactions in the reservoir of the geothermal system shift the Ca-Mg-HCO 3 type cold groundwaters to the Na-HCO 3-SO 4 type thermal waters. Thermal waters are oversaturated at discharge temperatures for aragonite, calcite, quartz, chalcedony, magnesite and dolomite minerals giving rise to a carbonate-rich scale. Gypsum and anhydrite minerals are undersaturated with all of the thermal waters. Boiling during ascent of the thermal fluids produces steam and liquid waters resulting in an increase of the concentrations of the constituents in discharge waters. Steam fraction, y, of the thermal waters of which temperatures are above 100°C is between 0.075 and 0.119. Reservoir pH is much lower than pH measured in the liquid phase separated at atmospheric conditions, since the latter experienced heavy loss of acid gases, mainly CO 2. Assessment of the various empirical chemical geothermometers and geochemical modelling suggest that reservoir temperatures vary between 175°C and 200°C.

  11. Shear velocity of the Rotokawa geothermal field using ambient noise (United States)

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


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

  12. Oxygen isotope systematics in an evolving geothermal system: Coso Hot Springs, California (United States)

    Etzel, Thomas M.; Bowman, John R.; Moore, Joseph N.; Valley, John W.; Spicuzza, Michael J.; McCulloch, Jesse M.


    Oxygen isotope and clay mineralogy studies have been made on whole rock samples and feldspar separates from three wells along the high temperature West Flank of the Coso geothermal system, California. The reservoir rocks have experienced variable 18O/16O depletion, with δ18O values ranging from primary values of + 7.5‰ down to - 4.6‰. Spatial patterns of clay mineral distributions in the three wells are not closely correlated with the distributions expected from measured, pre-production temperature profiles, but do correlate with spatial patterns of 18O/16O depletion, indicating that the stability of clay minerals in the three wells is a function of fluid-rock interaction in addition to temperature. Detailed δ18O measurements in the three wells identify a limited number of localized intervals of extensive 18O/16O depletion. These intervals document localized zones of higher permeability in the geothermal system that have experienced significant fluid infiltration, water-rock interaction and oxygen isotopic exchange with the geothermal fluids. The local zones of maximum 18O/16O depletion in each well correspond closely with current hot water production zones. Most feldspar separates have measured δ18O values too high to have completely attained oxygen isotope exchange equilibrium with the reservoir fluid at pre-production temperatures. In general, the lower the δ18O value of the feldspar, the closer the feldspar approaches exchange equilibrium with the geothermal fluid. This correlation suggests that fracture-induced increases in permeability increase both fluid infiltration and the surface area of the host rock exposed to geothermal fluid, promoting fluid-rock interaction and oxygen isotope exchange. The two most 18O/16O-depleted feldspar samples have δ18O values too low to be in exchange equilibrium with the pre-production reservoir fluid at pre-production temperatures. These discrepancies suggest that the reservoir fluid in the West Flank of the Coso

  13. Geothermal Investigations of California Submerged Lands and Spherical Flow in Naturally Fractured Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Northup, William F.; Everitts, D.J.; Eaton, C.F.; Welday, E.E.; Martin, Roger C.; Ershaghi, Iraj; Wilde, P.; Oldson, J.C.; Case, C.W.


    A large portion of California State-owned land is the tidal and submerged land along the coastline and around the islands that extends seaward for three geographical miles. Other large areas of State-owned lands form the beds of lakes and navigable rivers. Some evidence, such as the proximity of hot springs, indicates there may be important geothermal potential on these lands. The purpose of this project is to develop methods, tools, and interpretive techniques to explore for and evaluate geothermal resources on submerged lands. Presently, the state of the art is primitive because there has been little interest or effort in assessing the resource potential of submerged lands, and the limited work carried out thus far has been for scientific purposes. There has been a moderate amount of water temperature measuring for oceanographic or limnologic studies and fairly reliable techniques exist. There have been limited measurements of the temperature, thermal gradient, and heat flow in bottom sediment of the ocean area off California and from the lakes. Probably less than a dozen data points exist for State-owned land. This work was done using large equipment, such as piston corers with outrigger-mounted thermistors arrayed along the core barrels. To achieve penetration, such equipment requires heavy weights, strong cable, heavy duty winches, large crews and oceanographic research-type vessels or large barges, and this entails considerable expenses and logistical problems. Clearly, many hundreds, or thousands of data points are required for a remotely reliable evaluation of the resources. The first problem is to assess existing methods and develop others that will enable economical and efficient exploration for geothermal resources on submerged lands.

  14. Reservoir engineering studies of the Cerro Prieto geothermal field (United States)

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


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

  15. Geochemical evidence of drawdown in the Cerro Prieto geothermal field (United States)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  17. Identification of environmental issues: Hybrid wood-geothermal power plant, Wendel-Amedee KGRA, Lassen County, California: First phase report

    Energy Technology Data Exchange (ETDEWEB)


    The development of a 55 MWe power plant in Lassen County, California, has been proposed. The proposed power plant is unique in that it will utilize goethermal heat and wood fuel to generate electrical power. This report identifies environmental issues and constraints which may impact the proposed hybrid wood-geothermal power plant. (ACR)

  18. Results of investigation at the Ahuachapan Geothermal Field, El Salvador

    Energy Technology Data Exchange (ETDEWEB)

    Fink, J.B. (HydroGeophysics, Tucson, AZ (United States))


    The Ahuachapan Geothermal Field (AGF) is a 95 megawatt geothemal-sourced power-plant operated by the Comision Ejecutiva Hidroelectrica del Rio Lempa (CEL) of El Salvador. During the past decade, as part of an effort to increase in situ thermal reserves in order to realize the full generation capacity of the AGF, extensive surface geophysical coverage has been obtained over the AGF and the prospective Chipilapa area to the east. The geophysical surveys were performed to determine physical property characteristics of the known reservoir and then to search for similar characteristics in the Chipilapa area. A secondary objective was to evaluate the surface recharge area in the highlands to the south of the AGF. The principal surface electrical geophysical methods used during this period were DC resistivity and magnetotellurics. Three available data sets have been reinterpreted using drillhole control to help form geophysical models of the area. The geophysical models are compared with the geologic interpretations.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  20. Health effects and related standards for fossil-fuel and geothermal power plants. Volume 6 of health and safety impacts of nuclear, geothermal, and fossil-fuel electric generation in California. [In California

    Energy Technology Data Exchange (ETDEWEB)

    Case, G.D.; Bertolli, T.A.; Bodington, J.C.; Choy, T.A.; Nero, A.V.


    This report reviews health effects and related standards for fossil-fuel and geothermal power plants, emphasizing impacts which may occur through emissions into the atmosphere, and treating other impacts briefly. Federal regulations as well as California state and local regulations are reviewed. Emissions are characterized by power plant type, including: coal-fired, oil-fired, gas-fired, combined cycle and advanced fossil-fuel plants; and liquid and vapor geothermal systems. Dispersion and transformation of emissions are treated. The state of knowledge of health effects, based on epidemiological, physiological, and biomedical studies, is reviewed.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  2. Geothermal environmental studies, Heber Region, Imperial Valley, California. Environmental baseline data acquisition. Final report

    Energy Technology Data Exchange (ETDEWEB)


    The Electric Power Research Institute (EPRI) has been studying the feasibility of a Low Salinity Hydrothermal Demonstration Plant as part of its Geothermal Energy Program. The Heber area of the Imperial Valley was selected as one of the candidate geothermal reservoirs. Documentation of the environmental conditions presently existing in the Heber area is required for assessment of environmental impacts of future development. An environmental baseline data acquisition program to compile available data on the environment of the Heber area is reported. The program included a review of pertinent existing literature, interviews with academic, governmental and private entities, combined with field investigations and meteorological monitoring to collect primary data. Results of the data acquisition program are compiled in terms of three elements: the physical, the biological and socioeconomic settings.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  4. Industrially induced changes in Earth structure at the Geysers Geothermal Area, California (United States)

    Foulger, G. R.; Grant, C. C.; Ross, A.; Julian, B. R.

    Industrial exploitation is causing clearly-measurable changes in Earth structure at The Geysers geothermal area, California. Production at The Geysers peaked in the late 1980s at ˜3.5 × 10³ kg s-1 of steam and 1800 MW of electricity. It subsequently decreased by about 10% per year [Barker et al., 1992] because of declining reservoir pressure. The steam reservoir coincides with a strong negative anomaly (˜0.16, ˜9%) in the compressional-to-shear seismic wave speed ratio VP/ VS, consistent with the expected effects of low-pressure vapor-phase pore fluid [Julian et al., 1996]. Between 1991 and 1994 this anomaly increased in amplitude by up to about 0.07 (˜4%). This is consistent with the expected effects of continued pressure reduction and conversion of pore water to steam as a result of exploitation. These unique results show that VP/VS tomography can easily detect saturation changes caused by exploitation of reservoirs, and is a potentially valuable technique for monitoring environmental change. They also provide geophysical observational evidence that geothermal energy is not a renewable energy source.

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

    NARCIS (Netherlands)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  7. 3D Magnetotelluic characterization of the Coso GeothermalField

    Energy Technology Data Exchange (ETDEWEB)

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


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

  8. Geothermal probabilistic cost study

    Energy Technology Data Exchange (ETDEWEB)

    Orren, L.H.; Ziman, G.M.; Jones, S.C.; Lee, T.K.; Noll, R.; Wilde, L.; Sadanand, V.


    A tool is presented to quantify the risks of geothermal projects, the Geothermal Probabilistic Cost Model (GPCM). The GPCM model is used to evaluate a geothermal reservoir for a binary-cycle electric plant at Heber, California. Three institutional aspects of the geothermal risk which can shift the risk among different agents are analyzed. The leasing of geothermal land, contracting between the producer and the user of the geothermal heat, and insurance against faulty performance are examined. (MHR)

  9. Hydrogeology of the Owego-Apalachin Elementary School Geothermal Fields, Tioga County, New York (United States)

    Williams, John H.; Kappel, William M.


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

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

    KAUST Repository

    Keiding, Marie


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

  12. Alteration and Lithogeochemistry of Altered Rocks at Well KMJ-49 Kamojang Geothermal Field, West Java, Indonesia

    Directory of Open Access Journals (Sweden)



    Full Text Available Kamojang geothermal field is located in a 1.2 to 0.452 Ma. Quarternary volcanic caldera system. Around the geothermal field, there are several volcanoes (cinder cones which include: Gunung sanggar, Gunung ciharus, Gunung jawa, Gunung pasir jawa and Gunung cakra (here “gunung” means “mount”. The activity of this volcanic complex contributes greatly to the presence of Kamojang geothermal field, which forming steam dominated system with high temperature around 250oC. The system has capacities of 260 MWe and 140 MWe. Volcanic rocks found around the geothermal field have been altered in general and some of them are difficult to be identified their initial character. Thus, it is necessary to study alteration rocks and lithogeochemistry of a geothermal field. Based on this idea, this study uses some methods consisting of: petrographic, geochemical and alteration box plot analysis. The analyses have been conducted for the surface samples and alteration rocks of cutting from Well KMJ-49. This study is expected to improve the understanding on the characteristics of Kamojang geothermal field. AI and CCPI calculation results indicate that the surface samples have a value ranging from 20 to 34 AI and CCPI ranges from 63 to73. While subsurface samples have AI values around 15-46 and CCPI ranges from 68 to 86. The relations of CPPI and AI will be reflected in the texture and mineralogy of the type and condition of the rock.

  13. Regional Systems Development for Geothermal Energy Resources Pacific Region (California and Hawaii). Task 3: water resources evaluation. Topical report

    Energy Technology Data Exchange (ETDEWEB)

    Sakaguchi, J.L.


    The fundamental objective of the water resources analysis was to assess the availability of surface and ground water for potential use as power plant make-up water in the major geothermal areas of California. The analysis was concentrated on identifying the major sources of surface and ground water, potential limitations on the usage of this water, and the resulting constraints on potentially developable electrical power in each geothermal resource area. Analyses were completed for 11 major geothermal areas in California: four in the Imperial Valley, Coso, Mono-Long Valley, Geysers-Calistoga, Surprise Valley, Glass Mountain, Wendel Amedee, and Lassen. One area in Hawaii, the Puna district, was also included in the analysis. The water requirements for representative types of energy conversion processes were developed using a case study approach. Cooling water requirements for each type of energy conversion process were estimated based upon a specific existing or proposed type of geothermal power plant. The make-up water requirements for each type of conversion process at each resource location were then estimated as a basis for analyzing any constraints on the megawatts which potentially could be developed.

  14. Multidisciplinary exploration of the Tendaho Graben geothermal fields (United States)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  16. Radon and ammonia transects across the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Semprini, L.; Kruger, P.


    Radon and ammonia transects, conducted at the Cerro Prieto geothermal field, involve measurement of concentration gradients at wells along lines of structural significance in the reservoir. Analysis of four transects showed radon concentrations ranging from 0.20 to 3.60 nCi/kg and ammonia concentrations from 17.6 to 59.3 mg/l. The data showed the lower concentrations in wells of lowest enthalpy fluid and the higher concentrations in wells of highest enthalpy fluid. Linear correlation analysis of the radon-enthalpy data indicated a strong relationship, with a marked influence by the two-phase conditions of the produced fluid. It appears that after phase separation in the reservoir, radon achieves radioactive equilibrium between fluid and rock, suggesting that the phase separation occurs well within the reservoir. A two-phase mixing model based on radon-enthalpy relations allows estimation of the fluid phase temperatures in the reservoir. Correlations of ammonia concentration with fluid enthalpy suggests an equilibrium partitioning model in which enrichment of ammonia correlates with higher enthalpy vapor.

  17. Thermal and petrologic constraints on lower crustal melt accumulation under the Salton Sea Geothermal Field (United States)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  19. Engineered Geothermal System Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Petty, Susan


    In June 2009, AltaRock Energy began field work on a project supported by the U.S. Department of Energy entitled “Use of Multiple Stimulations to Improve Economics of Engineered Geothermal Systems in Shallow High Temperature Intrusives.” The goal of the project was to develop an Engineered Geothermal System (EGS) in the portion of The Geysers geothermal field operated by the Northern California Power Agency (NCPA). The project encountered several problems while deepening Well E-7 which culminated in the suspension of field activities in September 2009. Some of the problems encountered are particular to The Geysers area, while others might be encountered in any geothermal field, and they might be avoided in future operations.


    Directory of Open Access Journals (Sweden)

    Züheyr KAMACI


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)



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

  4. Geothermal feasibility study for City of Sonoma, California - four municipal buildings

    Energy Technology Data Exchange (ETDEWEB)


    The City of Sonoma, located in the Northern California Wine Country, consists of several buildings which are old and historic in nature. Four of these buildings, (which shall be designated 1 through 4), totaling approximately 31,150 square feet, shall be evaluated to determine the economic feasibility of converting the existing Environmental Control Systems to water source heat pumps utilizing a natural Geothermal heat sink. Presently, on the State Park's site, there exists a warm water well which produces 250 gallons per minute of water at 73/sup 0/F. Based on utility rates forecast by Pacific Gas and Electric, installation of heat pumps in the City buildings at Sonoma does not appear to be attractive. The economic evaluation was continued until the year 2000. Pacific Gas and Electric is re-evaluating its rate forecasts and will issue a new forecast in April 1982. The high capital cost is due to retrofitting the heating, ventilating, and air conditioning equipment for the existing buildings. For a new installation, the concept of using heat pumps should be re-evaluated.

  5. Determination of heat losses in the Cerro Prieto, Baja California, geothermal field steam transportation network based on the thermal insulation condition of the steam pipelines; Determinacion de perdidas de calor en la red de transporte de vapor del campo geotermico de Cerro Prieto, Baja California, con base en el estado fisico del aislamiento termico de vaporductos

    Energy Technology Data Exchange (ETDEWEB)

    Ovando Castelar, Rosember; Garcia Gutierrez, Alfonso; Martinez Estrella, Juan Ignacio [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail:; Canchola Felix, Ismael; Jacobo Galvan, Paul; Miranda Herrera, Carlos; Mora Perez, Othon [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, B.C. (Mexico)


    In Cerro Prieto Geothermal Field (CPGF), the steam from producing wells is transported to power plants through a large and complex system of pipes thermally insulated with a 2 inches thick mineral wool or a fiber glass layer and an external aluminum or iron cover. The insulation material has been exposed to weather conditions during the field operation and has suffered density and thickness changes. In some cases the insulation has been lost completely, increasing heat transfer from the pipes to the environment. This paper analyzes the impact of the conditions of thermal insulation on heat losses in the CPGF steam-pipeline network. The heat losses are calculated by applying an iterative method to determine the surface temperature based on a heat balance calculated from the three basic mechanisms of heat transfer: conduction, convection, and radiation. Finally, using length and diameter data corresponding to the condition of the thermal insulation of each pipeline-and field operation data, the overall heat losses are quantified for steam lines throughout the pipeline network in the field. The results allow us to evaluate the magnitude of the heat losses in comparison with the overall energy losses occurring during steam transport from wells to the power plants. [Spanish] En el Campo Geotermico de Cerro Prieto (CGCP), BC, el transporte de vapor desde los pozos hasta las plantas generadoras de electricidad se lleva a cabo mediante un extenso y complejo sistema de tuberias que tipicamente se encuentran aisladas termicamente con una capa de 2 pulgadas de material aislante a base de lana mineral o fibra de vidrio, y una proteccion mecanica de aluminio o hierro galvanizado. Debido a la exposicion a las condiciones meteorologicas a traves del tiempo de operacion del campo, el aislamiento ha experimentado cambios en su densidad y espesor y en ocasiones se ha perdido por completo, lo cual repercute en una mayor transferencia de calor de las tuberias hacia el medio ambiente

  6. Search for geothermal seismic noise in the East Mesa area, Imperial Valley, California

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, H.M.


    Seismic noise measurements were made in the East Mesa area of Imperial Valley, California, to find out if a noise anomaly was associated with the Mesa thermal anomaly. Thirty-three locations were occupied in the area using slow-speed tape-recording seismic systems. One of the stations (CEN) was operated close to where a geothermal test well was subsequently drilled by the U. S. Bureau of Reclamation. Several sources of cultural noise are present in the area. Large fluctuations in noise level, superposed on a constant high level of noise, occur from traffic on a freeway to the south of the region. There is noise generated by canals to the west and south and agricultural activity to the west of the region. Noise at 2.5 Hz frequency generated by a small waterfall (power drop) on the All American Canal propagates as far as 10 km. Average noise levels were computed at each station using several quiet samples selected from 4-hour sections of data recorded at night and contoured. Spatial distribution of 2 to 3 Hz noise shows noise radiating from the power drop. Noise in 0 to 2, 3 to 5, and 5 to 10 Hz bands show high levels extending along the freeway to the south and East High Line Canal to the west of the area. The Mesa thermal anomaly is centered about 2.5 km from the freeway and canal and does not seem to have any anomalous noise amplitudes associated with it. Additional results using data from two arrays of closely-spaced instruments extending from the freeway to the Mesa thermal anomaly also show no indications of high noise levels over the anomaly. This conclusion differs from the results of two previous surveys in the area (Douze and Sorrells, 1972; Geothermal Staff of Teledyne-Geotech, 1972) which show well defined noise anomalies in the 0 to 2, and 3 to 5 Hz frequency bands. A search was also made for anomalous features in noise spectra and for coherent wave trains indicating the presence of discrete sources of noise.

  7. Feasibility of geothermal space/water heating for Mammoth Lakes Village, California. Final report, September 1976--September 1977

    Energy Technology Data Exchange (ETDEWEB)

    Sims, A.V.; Racine, W.C.


    Results of a study to determine the technical, economic, and environmental feasibility of geothermal district heating for Mammoth Lakes Village, California are reported. The geothermal district heating system selected is technically feasible and will use existing technology in its design and operation. District heating can provide space and water heating energy for typical customers at lower cost than alternative sources of energy. If the district heating system is investor owned, lower costs are realized after five to six years of operation, and if owned by a nonprofit organization, after zero to three years. District heating offers lower costs than alternatives much sooner in time if co-generation and/or DOE participation in system construction are included in the analysis. During a preliminary environmental assessment, no potential adverse environmental impacts could be identified of sufficient consequence to preclude the construction and operation of the proposed district heating system. A follow-on program aimed at implementing district heating in Mammoth is outlined.

  8. Geothermal system boundary at the northern edge of Patuha Geothermal Field based on integrated study of volcanostratigraphy, geological field mapping, and cool springs contamination by thermal fluids (United States)

    Suryantini; Rachmawati, C.; Abdurrahman, M.


    Patuha Geothermal System is a volcanic hydrothermal system. In this type of system, the boundary of the system is often determined by low resistivity (10 ohm.m) anomaly from Magnetotelluric (MT) or DC-Resistivity survey. On the contrary, during geothermal exploration, the system boundary often need to be determined as early as possible even prior of resistivity data available. Thus, a method that use early stage survey data must be developed properly to reduce the uncertainty of the geothermal area extent delineation at the time the geophysical data unavailable. Geological field mapping, volcanostratigraphy analysis and fluid chemistry of thermal water and cold water are the data available at the early stage of exploration. This study integrates this data to delineate the geothermal system boundary. The geological mapping and volcanostratigraphy are constructed to limit the extent of thermal and cold springs. It results that springs in the study area are controlled hydrologically by topography of Patuha Volcanic Crown (complex) or so called PVC, the current geothermal field and Masigit Volcanic Crown (complex) or so called MVC, the dormant volcano not associated with active geothermal system. Some of the cold springs at PVC are contaminated by subsurface steam heated outflow while others are not contaminated. The contaminated cold springs have several characteristics such as higher water temperature than ambient temperature at the time it was measured, higher total disolved solid (TDS), and lower pH. The soluble elements analysis support the early contamination indication by showing higher cation and anion, and positive oxygen shifting of stable isotope of these cool springs. Where as the uncontaminated spring shows similar characteristic with cool springs occur at MVC. The boundary of the system is delineated by an arbitrary line drawn between distal thermal springs from the upflow or contaminated cool springs with the cool uncontaminated springs. This boundary is

  9. Thermal History of the Felsite Unit, Geysers Geothermal Field, From Thermal Modeling of 40Ar/39Ar Incremental Heating Data

    Energy Technology Data Exchange (ETDEWEB)

    T. M. Harrison (U of California); G. B. Dalrymple (Oregon State U); J. B. Hulen (U of Utah); M. A. Lanphere; M. Grove; O. M. Lovera


    An Ar-40/Ar-39 and U-Pb study was performed of the Geysers plutonic complex of the Geysers Geothermal Field in California. Sixty-nine ion microprobe spot analyses of zircons from four granite samples from the plutonic complex that underlies the Geysers geothermal field yielded Pb-207/Pb-206 vs. U-238/Pb-206 concordia ages ranging from 1.13 {+-} 0.04 Ma to 1.25 {+-} 0.04 Ma. The U-Pb ages coincide closely with Ar-40/Ar-39 age spectrum plateau and ''terminal'' ages from coexisting K-feldspars and with the eruption ages of overlying volcanic rocks. The data indicate that the granite crystallized at 1.18 Ma and had cooled below 350 C by {approximately}0.9-1.0 Ma. Interpretation of the feldspar Ar-40/Ar-39 age data using multi-diffusion domain theory indicates that post-emplacement rapid cooling was succeeded either by slower cooling from 350-300 C between 1.0 and 0.4 Ma or transitory reheating to 300-350 C at about 0.4-0.6 Ma. Heat flow calculations constrained with K-feldspar thermal histories and the pre sent elevated regional heal flow anomaly demonstrate that appreciable heat input from sources external to the known Geysers plutonic complex is required to maintain the geothermal system. This requirement is satisfied by either a large, underlying, convecting magma chamber (now solidified) emplaced at 1.2 Ma or episodic intrusion of smaller bodies from 1.2-0.6 Ma.

  10. Numerical simulations of passing seismic waves at the Larderello-Travale Geothermal Field, Italy (United States)

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


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

  11. Session: Geopressured-Geothermal

    Energy Technology Data Exchange (ETDEWEB)

    Jelacic, Allan J.; Eaton, Ben A.; Shook, G. Michael; Birkinshaw, Kelly; Negus-de Wys, Jane


    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. Seismicity, focal mechanisms, and stress distribution in the Tres Virgenes volcanic and geothermal region, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Victor; Munguia, Luis [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (Mexico)


    In October 1993 we carried out a seismic monitoring in the Tres Virgenes volcanic region in order to record the background seismicity associated with the volcanic structures, the geothermal field and the tectonic features of the area. Hypocenters for 257 microearthquakes were located in the volcanic edifices and along the northwest right-lateral, strike-slip La Virgen fault. Focal depths range from close to the Earth surface to about 8 km. Shallow depths occur mainly in the volcanic edifices. Deeper seismic events occurred outside the volcanic area. The duration magnitudes of the located microearthquakes range between 1 and 3. The Vp/Vs ratio and the low-Q values estimated suggest heterogeneous material properties in the volcanic structures mainly toward the El Azufre fault and the El Aguajito Caldera, where hydrothermal activity has been reported. The P- and T-axes of focal mechanisms for 90 microearthquakes suggest that the region is under N-S compression and E-W extension, in agreement with the regional tectonic stress field of the NW-SE right-lateral strike-slip transform fault system of the Gulf of California. [Spanish] En octubre de 1993 se llevo a cabo un monitoreo sismico en la region volcanica Las Tres Virgenes con el proposito de registrar la actividad sismica asociada a las estructuras volcanicas, al campo geotermico y a la tectonica local. Se localizaron 257 microsismos con hipocentros en los edificios volcanicos y a lo largo de la falla de rumbo, lateral derecha conocida como falla La Virgen. La profundidad focal de los sismos varia desde los muy cercanos a la superficie de la Tierra hasta los 8 km. Las profundidades someras ocurren principalmente en los edificios volcanicos. Los sismos mas profundos ocurren fuera del area volcanica. La magnitud de duracion de los microsismos localizados varia entre 1 y 3. La razon Vp/Vs y los valores bajos de Q que se estimaron en la zona sugieren un material con propiedades heterogeneas bajo las estructuras

  13. Draft environmental impact report. California Department of Water Resources, Bottle Rock geothermal power plant, Lake County, CA

    Energy Technology Data Exchange (ETDEWEB)


    The California Department of Water Resources (DWR) proposes to construct the Bottle Rock power plant, a 55 MW geothermal power plant, at The Geysers Known Geothermal Resource Area (KGRA). The plant is projected to begin operation in April of 1983, and will be located in Lake County near the Sonoma County line on approximately 7.2 acres of the Francisco leasehold. The steam to operate the power plant, approximately 1,000,000 pounds/h, will be provided by McCulloch Geothermal Corporation. The power plant's appearance and operation will be basically the same as the units in operation or under construction in the KGRA. The power plant and related facilities will consist of a 55 MW turbine generator, a 1.1 mile (1.81 km) long transmission line, a condensing system, cooling tower, electrical switchyard, gas storage facility, cistern, and an atmospheric emission control system. DWR plans to abate hydrogen sulfide (H/sub 2/S) emissions through the use of the Stretford Process which scrubs the H/sub 2/S from the condenser vent gas stream and catalytically oxides the gas to elemental sulfur. If the Stretford Process does not meet emission limitations, a secondary H/sub 2/S abatement system using hydrogen peroxide/iron catalyst is proposed. The Bottle Rock project and other existing and future geothermal projects in the KGRA may result in cumulative impacts to soils, biological resources, water quality, geothermal steam resources, air quality, public health, land use, recreation, cultural resources, and aesthetics.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  15. Double-diffusive convection in geothermal systems: the salton sea, California, geothermal system as a likely candidate (United States)

    Fournier, R.O.


    Much has been published about double-diffusive convection as a mechanism for explaining variations in composition and temperature within all-liquid natural systems. However, relatively little is known about the applicability of this phenomenon within the heterogeneous rocks of currently active geothermal systems where primary porosity may control fluid flow in some places and fractures may control it in others. The main appeal of double-diffusive convection within hydrothermal systems is-that it is a mechanism that may allow efficient transfer of heat mainly by convection, while at the same time maintaining vertical and lateral salinity gradients. The Salton Sea geothermal system exhibits the following reservoir characteristics: (1) decreasing salinity and temperature from bottom to top and center toward the sides, (2) a very high heat flow from the top of the system that seems to require a major component of convective transfer of heat within the chemically stratified main reservoir, and (3) a relatively uniform density of the reservoir fluid throughout the system at all combinations of subsurface temperature, pressure, and salinity. Double-diffusive convection can account for these characteristics very nicely whereas other previously suggested models appear to account either for the thermal structure or for the salinity variations, but not both. Hydrologists, reservoir engineers, and particularly geochemists should consider the possibility and consequences of double-diffusive convection when formulating models of hydrothermal processes, and of the response of reservoirs to testing and production. ?? 1990.

  16. Thermal modeling of step-out targets at the Soda Lake geothermal field, Churchill County, Nevada (United States)

    Dingwall, Ryan Kenneth

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

  17. Field Observed Salt Tolerance of California Pistachios (United States)

    Sanden, Blake; Fergusion, Lousie; Kallsen, Craig


    The general concept of crop salt tolerance is over simplified: consisting of a single soil saturation extract salinity threshold with a "% relative yield" decline function. This approach minimizes the real world variability in actual tree growth and yield due to additional specific ion toxicity and soil texture/anoxia. The current salinity tolerance function for California pistachios is essentially the same as cotton. It was developed from a small plot study in an 8 to 13 year old orchard in northwestern Kern County from 1997-2002 with a threshold of 9.4 dS/m ECe and an 8.4% relative yield decline above that level. These values were confirmed for seedling growth in saline sand-tank studies at the USDA Salinity Lab in Riverside, California. A second large scale field study applied fresh and saline irrigation treatments (0.5 to 5.2 dS/m EC) from planting through 10th leaf. Trees were commercially harvested starting in 2011. Average 2011-14 root zone salinity ranged from 2.5 to 13.2 dS/m and caused a significant edible inshell yield reduction of 108 to 264 kg/ha (depending on rootstock) in the combined 4 year yield: a 1 to 3% decline for every unit EC (dS/m) increase over 6 ds/m. A greatly expanded salinity survey including 10 commercial fields (9th - 15th leaf) in western Kern County with 140 individual tree data points ranging from an average root zone (1.5 m depth) salinity of 1.6 to 20.5 dS/m resulted in a similar yield reduction of 162 to 394 kg/ha (3 year cumulative inshell yield) for every unit ECe > 6.5 dS/m.

  18. Orthogonal Test Analysis on Conditions Affecting Electricity Generation Performance of an Enhanced Geothermal System at Yangbajing Geothermal Field

    Directory of Open Access Journals (Sweden)

    Yuchao Zeng


    Full Text Available The main conditions affecting electricity generation performance of an enhanced geothermal system (EGS include reservoir porosity, reservoir permeability, rock heat conductivity, water production rate and injection temperature. Presently there is lack of systematic research the relative importance of the five aforementioned conditions. The orthogonal test method is a statistical approach to analyze multi-factor and multi-level influence on system performance. In this work, based on the geological data at Yangbajing geothermal field, we analyzed the five conditions affecting the electricity generation performance of EGS, and ranked the relative importance of the five factors. The results show that the order of the relative importance of the conditions on electric power is water production rate > injection temperature > reservoir porosity > rock heat conductivity > reservoir permeability; the order of the relative importance of the conditions on reservoir impedance is reservoir permeability > injection temperature > water production rate > reservoir porosity > rock heat conductivity; the order of the relative importance of the conditions on pump power is water production rate > reservoir permeability > injection temperature > reservoir porosity > rock heat conductivity, and; the order of the relative importance of the conditions on energy efficiency is water production rate > reservoir permeability > reservoir porosity > injection temperature > rock heat conductivity. The construction of an EGS reservoir should be located at a formation with higher reservoir porosity or rock heat conductivity, while the determination of reservoir permeability, water production rate and injection temperature should be based on the comprehensive target.

  19. Prospects of development of highly mineralized high-temperature resources of the Tarumovskoye geothermal field (United States)

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


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

  20. Landslide oil field, San Joaquin Valley, California

    Energy Technology Data Exchange (ETDEWEB)

    Collins, B.P.; March, K.A.; Caballero, J.S.; Stolle, J.M.


    The Landslide field, located at the southern margin of the San Joaquin basin, was discovered in 1985 by a partnership headed by Channel Exploration Company, on a farm out from Tenneco Oil Company. Initial production from the Tenneco San Emidio 63X-30 was 2064 BOPD, making landslide one of the largest onshore discoveries in California during the past decade. Current production is 7100 BOPD from a sandstone reservoir at 12,500 ft. Fifteen wells have been drilled in the field, six of which are water injectors. Production from the Landslide field occurs from a series of upper Miocene Stevens turbidite sandstones that lie obliquely across an east-plunging structural nose. These turbidite sandstones were deposited as channel-fill sequences within a narrowly bounded levied channel complex. Both the Landslide field and the larger Yowlumne field, located 3 mi to the northwest, comprise a single channel-fan depositional system that developed in the restricted deep-water portion of the San Joaquin basin. Information from the open-hole logs, three-dimensional surveys, vertical seismic profiles, repeat formation tester data, cores, and pressure buildup tests allowed continuous drilling from the initial discovery to the final waterflood injector, without a single dry hole. In addition, the successful application of three-dimensional seismic data in the Landslide development program has helped correctly image channel-fan anomalies in the southern Maricopa basin, where data quality and severe velocity problems have hampered previous efforts. New exploration targets are currently being evaluated on the acreage surrounding the Landslide discovery and should lead to an interesting new round of drilling activity in the Maricopa basin.

  1. Determination of Ground Heat Exchangers Temperature Field in Geothermal Heat Pumps (United States)

    Zhurmilova, I.; Shtym, A.


    For the heating and cooling supply of buildings and constructions geothermal heat pumps using low-potential ground energy are applied by means of ground exchangers. The process of heat transfer in a system of ground exchangers is a phenomenon of complex heat transfer. The paper presents a mathematical modeling of heat exchange processes, the temperature fields are built which are necessary for the determination of the ground array that ensures an adequate supply of low potential energy excluding the freezing of soil around the pipes in the ground heat exchangers and guaranteeing a reliable operation of geothermal heat pumps.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  4. Assessment of geothermal development in the Imperial Valley of California. Volume 1. Environment, health, and socioeconomics

    Energy Technology Data Exchange (ETDEWEB)

    Layton, D. (ed.)


    Utilization of the Imperial Valley's geothermal resources to support energy production could be hindered if environmental impacts prove to be unacceptable or if geothermal operations are incompatible with agriculture. To address these concerns, an integrated environmental and socioeconomic assessment of energy production in the valley was prepared. The most important impacts examined in the assessment involved air quality changes resulting from emissions of hydrogen sulfide, and increases in the salinity of the Salton Sea resulting from the use of agricultural waste waters for power plant cooling. The socioeconomics consequences of future geothermal development will generally be beneficial. (MHR)

  5. Thermal modeling of the Clear Lake magmatic system, California: Implications for conventional and hot dry rock geothermal development

    Energy Technology Data Exchange (ETDEWEB)

    Stimac, J.; Goff, F.; Wohletz, K.


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  7. Small-Scale Geothermal Power Plant Field Verification Projects: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Kutscher, C.


    In the spring of 2000, the National Renewable Energy Laboratory issued a Request for Proposal for the construction of small-scale (300 kilowatt [kW] to 1 megawatt [MW]) geothermal power plants in the western United States. Five projects were selected for funding. Of these five, subcontracts have been completed for three, and preliminary design work is being conducted. The three projects currently under contract represent a variety of concepts and locations: a 1-MW evaporatively enhanced, air-cooled binary-cycle plant in Nevada; a 1-MW water-cooled Kalina-cycle plant in New Mexico; and a 750-kW low-temperature flash plant in Utah. All three also incorporate direct heating: onion dehydration, heating for a fish hatchery, and greenhouse heating, respectively. These projects are expected to begin operation between April 2002 and September 2003. In each case, detailed data on performance and costs will be taken over a 3-year period.

  8. Characterizing Fractures in Geysers Geothermal Field by Micro-seismic Data, Using Soft Computing, Fractals, and Shear Wave Anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Aminzadeh, Fred [Univ. of Southern California, Los Angeles, CA (United States); Sammis, Charles [Univ. of Southern California, Los Angeles, CA (United States); Sahimi, Mohammad [Univ. of Southern California, Los Angeles, CA (United States); Okaya, David [Univ. of Southern California, Los Angeles, CA (United States)


    The ultimate objective of the project was to develop new methodologies to characterize the northwestern part of The Geysers geothermal reservoir (Sonoma County, California). The goal is to gain a better knowledge of the reservoir porosity, permeability, fracture size, fracture spacing, reservoir discontinuities (leaky barriers) and impermeable boundaries.

  9. Origin of rainwater acidity near the Los Azufres geothermal field, Mexico (United States)

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


    The chemical and isotopic compositions of rainwater were monitored at Los Azufres geothermal field (88 MWe) and its surroundings during May - September 1995, which is the rainy season. Samples were collected from eight sites: three within the field, three in its surroundings and two sufficiently far from the field such that they have no geothermal input. The concentrations of Cl-, SO42- and NO3- were measured in about 350 samples and found to be generally rainwater sulfur. The determination of pH was found to be necessary, but is not sufficient to characterize rainwater acidity. The Gran titration method was used to determine alkalinity with respect to equivalence point of H2CO3(*). Values of alkalinity were found to range from 10-4 to 10-6 eq/L, and were negative only for some samples from Vivero and Guadalajara. Thus, SO42- and NO3- are in general not in acidic form (i.e. balanced by Na+, Ca2+, etc. rather than H+). Sulfate ??34S values were about -1.5??? in Los Azufres and its surroundings, and in Morelia, but differed from the value of -0.2??? for Guadalajara. The ??34S values for H2S from the Los Azufres geothermal wells are in the range -3.4 to 0.0???. The ??34S ranges for the natural and anthropogenic sources for environmental sulfur overlap, making it difficult to differentiate between the contribution of different sources. However, a similarity of values of ??34S at Los Azufres and Morelia (85 km distant) suggest a regional source of sulfate that is not associated with geothermal emissions from Los Azufres. (C) 2000 Published by Elsevier Science Ltd on behalf of CNR.The chemical compositions of rainwater were analyzed at Los Azufres geothermal field in Spain from May-September 1995. The concentrations of Cl-, SO42- and NO3- were measured and found to be generally rainwater sulfur.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  11. Sustainable energy development and water supply security in Kamojang Geothermal Field: The Energy-Water Nexus (United States)

    Sofyan, Y.; Nishijima, J.; Fujimitsu, Y.


    The Kamojang Geothermal Field (KGF) is a typical vapor dominated hydrothermal system in West Java, Indonesia. This geothermal field is the oldest exploited geothermal field in Indonesia. From 1983 to 2005, more than 160 million tons of steam have been exploited from the KGF and more than 30 million tons of water were injected into the reservoir system. The injected water come from condensed water, local river and ground water. Sustainable production in the geothermal energy development is the ability of the production system applied to sustain the stable production level over long times and to manage the mass balance between production, injection and natural recharge in the geothermal reservoir during exploitation. Mass balance in the reservoir system can be monitored by using time lapse gravity monitoring. Mass variation of hydrodynamic in the reservoir of KGF from 1999 to 2005 is about -3.34 Mt/year while is about -3.78 Mt/year from 1999 to 2008. Another period between 2009 and 2010, mass variation decreased about -8.24 Mt. According to the history of production and injection, natural recharge to the KGF's reservoir is estimated at about 2.77 Mt/year from 1999 to 2005 and 2.75 Mt/year from 1999 to 2008. Between 2009 and 2010, KGF has a bigger mass deficiency rate throughout 200 MWe maintain production. Large amount of fresh water is needed for sustainable geothermal energy production, while the domestic water supply need is also increased. Natural recharge, about 50% of injected water, cooling system, drilling and other production activities in KGF spend large amounts of fresh water. Water consumption for local people around KGF is about 1.46 MT/year. The water volume around KGF of total runoff is the range between dry season 0.07 MT/month and rainy season 4.4 MT/month. The water demands for sustainable geothermal production of KGF and for local people's consumption will increase in the future. Integrated planning between the energy and water sectors in KGF

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  13. Economic study of low temperature geothermal energy in Lassen and Modoc Counties, California

    Energy Technology Data Exchange (ETDEWEB)


    The feasibility of using low cost, low temperature geothermal energy in job-producing industries to increase employment and encourage economic development was investigated. The study, encompassing all of Lassen and Modoc Counties, was to be site-specific, referencing candidate geothermal applications to known hot wells and springs as previously determined, or to new wells with specific characteristics as defined in the Scope of Work. The emphasis was to be placed on economically practical and readily achievable applications from known resources. Although both positive and negative findings were found in specific areas of investigation, it is felt that the overall long term prognosis for geothermal energy stimulus to industry in the area is excellent. The applications studied were; greenhouse heating, kiln drying, onion dehydration, feedlots, and aquaculture.

  14. Ultrasonic measurements at in-situ conditions in a geothermal field: Ngatamariki field, New Zealand. (United States)

    Durán, E.; Adam, L.; Wallis, I. C.


    A set volcaniclastic and pyroclastic rocks were collected from Ngatamariki Geothermal Field. Two sets of measurements were carried out in core samples from geological intervals used for injection. The first set of measurements were made at surface conditions using ultrasonic transducers. The second measurements were made simulating in-situ confining and fluid pressures of the field inside a pressure vessel. A comparison of both approaches is made in order to validate existing data and expand the geophysical information collected in the field. Previous work on the rocks has shown that there is large variation in the physical and mechanical properties with depth, which might indicate that effects of lithology and hydrothermal alteration are controlling factors in the observed variability, nevertheless the addition of fluid pressures has never been studied in these rocks. Both datasets have been used to improve the identification and interpretation of P and S-wave arrivals and understand their variation with pressure and fluid content. Previous laboratory results on mineralogy, clay content, porosity, permeability, crack density and orientation are incorporated into the analysis. Finally, a methodology is presented to aid in the calibration and interpretation of S-wave arrivals for the transducers built to perform the experiments at in-situ conditions. Since the compressional and shear piezoelectric crystals used are packed in a single casing, converted waves must be identified on top of the direct arrivals. By comparing the source signature of the measurements performed on the bench to the waveforms recorded at field conditions, we aid the eye interpretation of picked times by adapting a Dynamic Time Warping algorithm for the task.

  15. Preliminary reservoir engineering studies of the Miravalles geothermal field, Costa Rica

    Energy Technology Data Exchange (ETDEWEB)

    Haukwa, C.; Bodvarsson, G.S. Lippmann, M.J. (Lawrence Berkeley Lab., CA (United States)); Mainieri, A. (Instituto Costarricense de Electricidad, San Jose (Costa Rica))


    The Earth Sciences Division of Lawrence Berkeley Laboratory in cooperation with the Instituto Costarricense de Electricidad is conducting a reservoir engineering study of the Miravalles geothermal field, Costa Rica. Using data from eight exploration wells a two-dimensional areal, natural-state model of Miravalles has been developed. The model was calibrated by fitting the observed temperature and pressure distributions and requires a geothermal upflow zone in the northern part of the field, associated with the Miravalles volcano and an outflow towards the south. The total hot (about 260[degrees]C) water recharge is 130 kg/s, corresponding to a thermal input of about 150 MWt. On the basis of the natural-state model a two-dimensional exploitation model was develope. The field has a production area of about 10 km[sup 2], with temperatures exceeding 220[degrees]C. The model indicated that power generation of 55 MWe can be maintained for 30 years, with or without injection of the separated geothermal brine. Generation of 110 MWe could be problematic. Until more information becomes available on the areal extent of the field and the properties of the reservoir rocks, especially their relative permeability characteristics, it is difficult to ascertain if 110 MWe can be sustained during a 30-year period.

  16. Preliminary reservoir engineering studies of the Miravalles geothermal field, Costa Rica

    Energy Technology Data Exchange (ETDEWEB)

    Haukwa, C.; Bodvarsson, G.S. Lippmann, M.J. [Lawrence Berkeley Lab., CA (United States); Mainieri, A. [Instituto Costarricense de Electricidad, San Jose (Costa Rica)


    The Earth Sciences Division of Lawrence Berkeley Laboratory in cooperation with the Instituto Costarricense de Electricidad is conducting a reservoir engineering study of the Miravalles geothermal field, Costa Rica. Using data from eight exploration wells a two-dimensional areal, natural-state model of Miravalles has been developed. The model was calibrated by fitting the observed temperature and pressure distributions and requires a geothermal upflow zone in the northern part of the field, associated with the Miravalles volcano and an outflow towards the south. The total hot (about 260{degrees}C) water recharge is 130 kg/s, corresponding to a thermal input of about 150 MWt. On the basis of the natural-state model a two-dimensional exploitation model was develope. The field has a production area of about 10 km{sup 2}, with temperatures exceeding 220{degrees}C. The model indicated that power generation of 55 MWe can be maintained for 30 years, with or without injection of the separated geothermal brine. Generation of 110 MWe could be problematic. Until more information becomes available on the areal extent of the field and the properties of the reservoir rocks, especially their relative permeability characteristics, it is difficult to ascertain if 110 MWe can be sustained during a 30-year period.

  17. Preliminary reservoir engineering studies of the Miravalles geothermal field, Costa Rica

    Energy Technology Data Exchange (ETDEWEB)

    Haukwa, C.; Bodvarsson, G.S.; Lippmann, M.J.; Mainieri, A.


    The Earth Sciences Division of Lawrence Berkeley Laboratory in cooperation with the Instituto Costarricense de Electricidad is conducting a reservoir engineering study of the Miravalles geothermal field, Costa Rica. Using data from eight exploration wells, a two-dimensional areal, natural-state model of Miravalles has been developed. The model was calibrated by fitting the observed temperature and pressure distributions and requires a geothermal upflow zone in the northern part of the field, associated with the Miravalles volcano and an outflow towards the south. The total hot (about 260 C) water recharge is 130 kg/s, corresponding to a thermal input of about 150 MWt. On the basis of the natural-state model a two-dimensional exploitation model was developed. The field has a production area of about 10 km{sup 2}, with temperatures exceeding 220 C. The model indicated that power generation of 55 MWe can be maintained for 30 years, with or without injection of the separated geothermal brine. Generation of 110 MWe could be problematic. Until more information becomes available on the areal extent of the field and the properties of the reservoir rocks, especially their relative permeability characteristics, it is difficult to ascertain if 110 MWe can be sustained during a 30-year period.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  20. Curie point depth from spectral analysis of aeromagnetic data from Cerro Prieto geothermal area, Baja California, México (United States)

    Espinosa-Cardeña, J. M.; Campos-Enriquez, J. O.


    Using aeromagnetic data acquired in the area from the Cerro Prieto geothermal field, we estimated the depth to the Curie point isotherm, interpreted as the base of the magnetic sources, following statistical spectral-based techniques. According to our results the Curie point isotherm is located at a depths ranging from 14 to 17 km. Our result is somewhat deeper than that obtained previously based only in 2-D and 3-D forward modeling of previous low-quality data. However, our results are supported by independent information comprising geothermal gradients, seismicity distribution in the crust, and gravity determined crustal thickness. Our results imply a high thermal gradient (ranging between 33 and 38 °C/km) and high heat flow (of about 100 mW/m 2) for the study area. The thermal regime for the area is inferred to be similar to that from the Salton trough.

  1. Spectral reflectance analysis of hydrothermal alteration in drill chips from two geothermal fields, Nevada (United States)

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


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

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

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, R.W.; Domingo, N.


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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. Drilling and operating oil, gas, and geothermal wells in an H/sub 2/S environment

    Energy Technology Data Exchange (ETDEWEB)

    Dosch, M.W.; Hodgson, S.F.


    The following subjects are covered: facts about hydrogen sulfides; drilling and operating oil, gas, and geothermal wells; detection devices and protective equipment; hazard levels and safety procedures; first aid; and H/sub 2/S in California oil, gas, and geothermal fields. (MHR)

  6. Geothermal direct heat use: market potential/penetration analysis for Federal Region IX (Arizona, California, Hawaii, Nevada)

    Energy Technology Data Exchange (ETDEWEB)

    Powell, W.; Tang, K. (eds.)


    A preliminary study was made of the potential for geothermal direct heat use in Arizona, California, Hawaii, and Nevada (Federal Region IX). The analysis for each state was performed by a different team, located in that state. For each state, the study team was asked to: (1) define the resource, based on the latest available data; (2) assess the potential market growth for geothermal energy; and (3) estimate the market penetration, projected to 2020. Each of the four states of interest in this study is unique in its own way. Rather than impose the same assumptions as to growth rates, capture rates, etc. on all of the study teams, each team was asked to use the most appropriate set of assumptions for its state. The results, therefore, should reflect the currently accepted views within each state. The four state reports comprise the main portion of this document. A brief regional overview section was prepared by the Jet Propulsion Laboratory, following completion of the state reports.

  7. Consideration of geological aspects and geochemical parameters of fluids in Bushdi geothermal field, south of mount Sabalan, NW Iran (United States)

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


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

  8. Matched Filter Detection of Microseismicity at Ngatamariki and Rotokawa Geothermal Fields, Central North Island, New Zealand (United States)

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


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

  9. Three-dimensional Magnetotelluric Characterization of the Xinzhou Geothermal Field, Southeastern China (United States)

    Han, Q.; Hu, X.; Cai, J.; Wei, W.


    Xinzhou geothermal field is located in the Guangdong province and adjacent to the China South Sea, and its hot springs can reach up to 92 degree Celsius. Yanshanian granite expose widely in the south of this geothermal field and four faults cut across each other over it. A dense grid of 176 magnetotelluric (MT) sites with broadband has been acquired over the Xinzhou geothermal field and its surrounding area. Due to the related electromagnetic (EM) noise one permanent observatory was placed as a remote reference to suppress this cultural EM noise interference. The datasets are processed using the mutual reference technique, static shift correction, and structural strike and dimensionality analysis based on tensor decomposition. Data analysis reveals that the underground conductivity structure has obvious three-dimensional characterization. For the high resolution result ,two and three dimensional inversion are both applied in this area employing the non-linear conjugate gradient method (NLCG).These MT data sets are supposed to detect the deep subsurface resistivity structure correlated to the distribution of geothermal reservoir (such as faults and fractured granite) and investigate the channel of the upwelling magma. The whole and cold granite usually present high resistivity but once it functions as reservoir the resistivity will decrease, sometimes it is hard to separate the reservoir from the cap layer. The 3D inversion results delineate three high resistivity anomalies distributed in different locations. At last we put forward that the large areas of granite form the major thermal source for the study area and discuss whether any melt under these magma intrusions exists.

  10. Open questions on the origin of life at anoxic geothermal fields. (United States)

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


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

  11. Steam and Brine Zone Prediction around Geothermal Reservoir Derived from Delay Time Seismic Tomography and Anisotropy Case Study: “PR” Geothermal Field (United States)

    Hendrawan Palgunadi, Kadek; Nugraha, A. D.; Sule, R.; Meidiana, T.


    Development of geothermal production can be conducted in several ways, one of them analyses the fracture or crack and structure within the reservoir. Due to low permeability and porosity value within the reservoir in geothermal field. This crack or fracture provide porosity for fluid storage and permeability for fluid movement and play a major role in production from this kind of reservoir. Structure and polarization direction can be derived from anisotropy parameter and seismic velocity parameter in geothermal field. In this study, we used micro-earthquake data of 1,067 events that were recorded by the average of 15 stations during almost 1-year measurement. We used anisotropy parameter using 3-D shear-wave splitting (SWS) tomography method to represent the distribution of anisotropy medium around the geothermal field. Two parameters produced from the S-wave analysis, which is polarization direction and delay time between fast S-wave and slow S-wave. To determine SWS parameters, we used a rotation of horizontal seismogram including N-S component and E-W component. Furthermore, we used short-time fourier transform (STFT) to calculate lag time and time window based on wave periods. Two horizontal components have been rotated from azimuth 0° to 180° with an increment of 1°. Cross-correlation coefficient used every azimuth of two horizontal components based on delay time with predetermined time window obtained by STFT. When cross-correlation coefficient is high, the corresponding value of delay time and azimuth are chosen as the polarization direction and delay time of SWS. Normalized time different divided by total ray length was used to determine the distribution of crack density. Through correlation of seismic velocity model, crack density, and 3-D anisotropy tomography, we can delineate a geothermal reservoir model. Our results show, high degree of anisotropy and crack density occur in the northern and eastern part of “PR” geothermal field for further

  12. Sustainable development of geothermal fields in the Pannonian Basin - A case study

    Energy Technology Data Exchange (ETDEWEB)

    Panu, Dumitru; Mitrofan, Horia; Serbu, Viorel


    As suggested by the discusssion of Barker, 1988, on the influence of flow dimension on the late-time behaviour of the generalized line source solution, it was inferred that observed long term reservoir pressure decline was an outcome of the 1D (linear) flow geometry, indicated by well tests. The detrimental effects of the reservoir pressure decline can be partly mitigated by taking advantage of the two-phase flow which occurs when methane, originally dissolved in the geothermal brine, is released within the well bore. Sustainable artesiar withdrawal scenarios for existing geothermal fields are devised, based on an accurate prediction of bottomhole pressure decline trends and an adequate selection of the diameter and length of the production tubing. Overall analysis and forecast are performed by an integrated reservoir & well bore simulator.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  14. A brine interface in the Salton Sea Geothermal System, California: Fluid geochemical and isotopic characteristics (United States)

    Williams, Alan E.; McKibben, Michael A.


    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 (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.

  15. Baseline studies in the desert ecosystem at East Mesa Geothermal Test Site, Imperial Valley, California

    Energy Technology Data Exchange (ETDEWEB)

    Romney, E.M.; Wallace, A.; Lunt, O.R.; Ackerman, T.A.; Kinnear, J.E.


    Baseline data reported herein for soil, vegetation, and small mammal components of the East Mesa desert ecosystem represent a collection period from October 1975 to September 1977. Inasmuch as changes in salt balance from geothermal brine sources are of potential impact upon the ecosystem, considerable analytical effort was given to the determination of element constituents in soil, plant, and animal samples. A preliminary synthesis of data was done to investigate the heterogeneity of element constituents among the sampled population and to summarize results. Findings indicate that periodic sampling and chemical analysis of vegetation around an industrialized geothermal energy source is probably the best way to monitor the surrounding ecosystem for assuring containment of any resource pollutants.

  16. Reservoir Characterization around Geothermal Field, West Java, Indonesia Derived from 4-D Seismic Tomography (United States)

    Verdhora Ry, Rexha; Nugraha, A. D.


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

  17. Siting and drilling recommendations for a geothermal exploration well, Wendel-Amedee KGRA, Lassen County, California

    Energy Technology Data Exchange (ETDEWEB)

    McNitt, J.R.; Wilde, W.R.


    All available exploration data relevant to the GeoProducts leasehold in the Wendel-Amedee KGRA are reviewed and interpreted. On the basis of this interpretation, locations and procedures are recommended for drilling geothermal production wells capable of supplying fluid at a temperature of 250/sup 0/F or greater. The following are covered: stratigraphy and geological history, geologic structure, geochemistry, geophysics, temperature-gradient data, and fluid quality. (MHR)

  18. Reconnaissance of geothermal resources near US naval facilities in the San Diego area, California

    Energy Technology Data Exchange (ETDEWEB)

    Youngs, L.G.


    A reconnaissance study has found little evidence of potential geothermal resources useful at naval facilities in the greater San Diego metropolitan area. However, there is a zone of modest elevated water well temperatures and slightly elevated thermal gradients that may include the eastern portion of the Imperial Beach Naval Air Station south of San Diego Bay. An increase of 0.3/sup 0/ to 0.4/sup 0/F/100 ft over the regional thermal gradient of 1.56/sup 0/F/100 ft was conservatively calculated for this zone. The thermal gradient can be used to predict 150/sup 0/F temperatures at a depth of approximately 4000 ft. This zone of greatest potential for a viable geothermal resource lies within a negative gravity anomaly thought to be caused by a tensionally developed graben, approximately centered over the San Diego Bay. Water well production in this zone is good to high, with 300 gpm often quoted as common for wells in this area. The concentration of total dissolved solids (TDS) in the deeper wells in this zone is relatively high due to intrusion of sea water. Productive geothermal wells may have to be drilled to depths economically infeasible for development of the resource in the area of discussion.

  19. Economic study of low temperature geothermal energy in Lassen and Modoc counties, California

    Energy Technology Data Exchange (ETDEWEB)



    The purpose of this study was to investigate the feasibility of using low cost, low temperature geothermal energy in job-producing industries to increase employment and encourage economic development. The study, encompassing all of Lassen and modoc Counties, was to be site-specific, referencing candidate geothermal applications to known hot wells and springs as previously determined, or to new wells with specific characteristics as defined in the Scope of Work. The emphasis was to be placed on economically practical and readily achievable applications from known resources, thus complimenting the recently completed ERDA-Susanville Study where a designated community was used as a ''laboratory'' in which land-use planning, institutional aspects, geological assessments, technical modeling and socioeconomic impacts were all examined in overview. During the course of the study, monthly progress reports were prepared and reviewed with the Commission so that emphasis on particular features of study could be changed as necessary to reflect updated findings and to redirect efforts into additional areas of potential promise as they became apparent. In this manner, a degree of flexibility was maintained which allowed a more comprehensive study than would have been otherwise possible. Although the report generates both positive and negative findings in specific areas of investigation, it is felt that the overall long term prognosis for geothermal energy stimulus to industry in the area is excellent.

  20. Geothermic field and development of the structure of continents (United States)

    Beloussov, V. V.


    Tectonic, magmatic and metamorphic processes combine into endogenous regimes. There is direct correlation between the degree of excitation of endogenous regimes and observed heat flow. There are grounds to suppose that all varieties of endogenous regimes, their distribution and their history depend on the heterogeneity in space and time of the Earth's thermal field.

  1. Flow rate decline and pressure transient in the Larderello geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Neri, Guiseppe


    The production history of most of the Larderello wells, both the older ones and the recent ones, that we have produced at constant pressure, is characterised by a rapid initial decline. In this study such a decline is interpreted as the consequence of an original flow regime of the “depletion” type being followed by a “diffusion” type regime. Such an interpretation, which does prove consistent with the phenomenology of the geothermal field, was suggested by the results of the analyses of the well-closure tests carried out in the North zone of Larderello and in the Travale field.

  2. Geothermal space/water heating for Mammoth Lakes Village, California. Quarterly technical progress report, 13 December 1976-12 March 1977

    Energy Technology Data Exchange (ETDEWEB)

    Sims, A.V.; Racine, W.C.


    During the second three months of this feasibility study to determine the technical, economic and environmental feasibility of heating Mammoth Lakes Village, California using geothermal energy, the following work was accomplished. A saturation survey of the number and types of space and water heaters currently in use in the Village was completed. Electric energy and ambient temperature metering equipment was installed. Peak heating demand for Mammoth Lakes was estimated for the years 1985, 1990 and 2000. Buildings were selected which are considered typical of Mammoth Lakes in terms of their heating systems to be used in estimating the cost of installing hydronic heating systems in Mammoth. Block diagrams and an order of magnitude cost comparison were prepared for high-temperature and low-temperature geothermal district heating systems. Models depicting a geothermal district heating system and a geothermal-electric power plant were designed, built and delivered to ERDA in Washington. Local input to the feasibility study was obtained from representatives of the State of California Departments of Transportation and Fish and Game, US Forest Service, and Mono County Planning Department.

  3. Monitoring ground-surface heating during expansion of the Casa Diablo production well field at Mammoth Lakes, California (United States)

    Bergfeld, D.; Vaughan, R. Greg; Evans, William C.; Olsen, Eric


    The Long Valley hydrothermal system supports geothermal power production from 3 binary plants (Casa Diablo) near the town of Mammoth Lakes, California. Development and growth of thermal ground at sites west of Casa Diablo have created concerns over planned expansion of a new well field and the associated increases in geothermal fluid production. To ensure that all areas of ground heating are identified prior to new geothermal development, we obtained high-resolution aerial thermal infrared imagery across the region. The imagery covers the existing and proposed well fields and part of the town of Mammoth Lakes. Imagery results from a predawn flight on Oct. 9, 2014 readily identified the Shady Rest thermal area (SRST), one of two large areas of ground heating west of Casa Diablo, as well as other known thermal areas smaller in size. Maximum surface temperatures at 3 thermal areas were 26–28 °C. Numerous small areas with ground temperatures >16 °C were also identified and slated for field investigations in summer 2015. Some thermal anomalies in the town of Mammoth Lakes clearly reflect human activity.Previously established projects to monitor impacts from geothermal power production include yearly surveys of soil temperatures and diffuse CO2 emissions at SRST, and less regular surveys to collect samples from fumaroles and gas vents across the region. Soil temperatures at 20 cm depth at SRST are well correlated with diffuse CO2 flux, and both parameters show little variation during the 2011–14 field surveys. Maximum temperatures were between 55–67 °C and associated CO2 discharge was around 12–18 tonnes per day. The carbon isotope composition of CO2 is fairly uniform across the area ranging between –3.7 to –4.4 ‰. The gas composition of the Shady Rest fumarole however has varied with time, and H2S concentrations in the gas have been increasing since 2009.

  4. Analysis and interpretation of stress indicators in deviated wells of the Coso Geothermal Field (United States)

    Schoenball, Martin; Glen, Jonathan M. G.; Davatzes, Nicholas C.


    Characterizing the tectonic stress field is an integral part for the development of hydrothermal systems, especially enhanced geothermal systems (EGS). With a known stress field, critically stressed faults can be identified. Faults that are critically oriented with respect to the in-situ stress field exhibit a high tendency for slip, and thus are likely candidates for reactivation during the creation of an EGS. Reactivated faults are known to serve as dominant fluid pathways during hydrothermal circulation and the characteristics of this process determine the potential for damaging earthquakes; should extensive portions of well-oriented, large features be reactivated. As part of the FORGE initiative at the West Flank of the Coso Geothermal Field, we analyze a large set of image logs obtained from wells distributed across the geothermal field for details about the stress state revealed by indicators such as borehole breakouts and drilling-induced tensile fractures. Previous stress analyses at Coso have ignored deviated well sections, since their interpretation for the orientation of the stress tensor is non-unique with respect to varying stress magnitudes. Using interpreted borehole-induced structures, we perform a grid search over all possible Andersonian stress states and find a best fitting vertical stress tensor for each stress state characterized by principal stress magnitudes. By including deviated well sections and recently drilled wells, we considerably expand the suite of stress measurements in the Coso Geothermal Field. Along individual wells, this analysis also reveals local meter length-scale deviations from the best-fitting mean stress orientation. While most wells show consistent horizontal principal stress orientations with standard deviations of about 10°, other wells show large standard deviations on the order of 25°. Several regions have logged well trajectories with lateral spacing below 1 km. This enables us to trace changes of the stress

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

    CERN Document Server

    Augustin, Matthias Albert


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

  6. Preliminary isotopic studies of fluids from the Cerro Prieto geothermal field (United States)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  8. Preliminary Studies of the Reservoir Capacity and the Generating Potential of the Baca Geothermal Field, New Mexico (United States)

    Bodvarsson, G. S.; Haar, S. Vonder; Wilt, M.; Tsang, C. F.


    A 50-MWe geothermal power plant is being considered for the Baca site in the Valleys Caldera, New Mexico, as a joint venture of the Department of Energy (DOE) and Union Oil Company of California. To date, over 20 wells have been drilled on the prospect, and the data from these wells indicate the presence of a high-temperature, liquid-dominated reservoir. In this paper, data from the open literature on the physical characteristics of the field are used to estimate the amount of hot water in place (reservoir capacity) and the length of time the reservoir can supply steam for a 50-MWe power plant (reservoir longevity). The reservoir capacity is estimated to be 1012 kg of hot fluid by volumetric calculations using existing geological, geophysical, and well data. The criteria used are described and the sensitivity of the results discussed. The longevity of the field is studied using a two-phase numerical simulator (SHAFT79). A number of cases are simulated based upon different boundary conditions and upon injection and production criteria. The results obtained from the simulation studies indicate that it is questionable that the Baca field can supply enough steam for a 50-MWe power plant for 30 years. Although the estimated reservoir reserves greatly exceed those needed for a 50-MWe power plant, the low transmissivity of the reservoir would cause localized boiling and rapid pressure decline during exploitation. It is therefore apparent that the conventional zero-dimensional (lumped parameter models) cannot be used to evaluate the generating capacities of low-permeability fields such as the Baca field.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  10. Probabilistic approach of resource assessment in Kerinci geothermal field using numerical simulation coupling with monte carlo simulation (United States)

    Hidayat, Iki; Sutopo; Pratama, Heru Berian


    The Kerinci geothermal field is one phase liquid reservoir system in the Kerinci District, western part of Jambi Province. In this field, there are geothermal prospects that identified by the heat source up flow inside a National Park area. Kerinci field was planned to develop 1×55 MWe by Pertamina Geothermal Energy. To define reservoir characterization, the numerical simulation of Kerinci field is developed by using TOUGH2 software with information from conceptual model. The pressure and temperature profile well data of KRC-B1 are validated with simulation data to reach natural state condition. The result of the validation is suitable matching. Based on natural state simulation, the resource assessment of Kerinci geothermal field is estimated by using Monte Carlo simulation with the result P10-P50-P90 are 49.4 MW, 64.3 MW and 82.4 MW respectively. This paper is the first study of resource assessment that has been estimated successfully in Kerinci Geothermal Field using numerical simulation coupling with Monte carlo simulation.

  11. Detailed microearthquake studies at the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

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


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

  12. Identification of natural fractures and in situ stress at Rantau Dedap geothermal field (United States)

    Artyanto, Andika; Sapiie, Benyamin; Idham Abdullah, Chalid; Permana Sidik, Ridwan


    Rantau Dedap Area is a geothermal field which is located in Great Sumatra Fault (GSF). The fault and fracture are main factor in the permeability of the geothermal system. However, not all faults and fractures have capability of to flow the fluids. Borehole image log is depiction of the borehole conditions, it is used to identify the natural fractures and drilling induced fracture. Both of them are used to identify the direction of the fracture, direction of maximum horizontal stress (SHmax), and geomechanics parameters. The natural fractures are the results of responses to stress on a rock and permeability which controlling factor in research area. Breakouts is found in this field as a trace of drilling induced fracture due to in situ stress work. Natural fractures are strongly clustered with true strike trending which first, second, and third major direction are N170°E – N180°E (N-S), N60°E – N70°E (NE-SW), and N310°E – N320°E (NW-SE), while the dominant dip is 80° –90°. Based on borehole breakout analysis, maximum horizontal stress orientation is identified in N162°E – N204°E (N-S) and N242°E (NE-SW) direction. It’s constantly similar with regional stress which is affected by GSF. Several parameters have been identified and analyzed are SHmax, SHmin, and Sy. It can be concluded that Rantau Dedap Geothermal Field is affected by strike-slip regime. The determination of in situ stress and natural fractures are important to study the pattern of permeability which is related to the fault in reservoir of this field.

  13. Compartmentalization of the Coso East Flank geothermal field imaged by 3-D full-tensor MT inversion (United States)

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


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

  14. Monitoring Biological Activity at Geothermal Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Peter Pryfogle


    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.

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

    Energy Technology Data Exchange (ETDEWEB)


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

  16. Geothermal Today - 1999

    Energy Technology Data Exchange (ETDEWEB)



    U.S. Department of Energy 1999 Geothermal Energy Program Highlights The Hot Facts Getting into Hot Water Turning Waste water into Clean Energy Producing Even Cleaner Power Drilling Faster and Cheaper Program in Review 1999: The Year in Review JanuaryCal Energy announced sale of Coso geothermal power plants at China Lake, California, to Caithness Energy, for $277 million. U.S. Export-Import Bank completed a $50 million refinancing of the Leyte Geothermal Optimization Project in the Philippines. F

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

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G.


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

  18. Trace element hydrochemistry indicating water contamination in and around the Yangbajing geothermal field, Tibet, China. (United States)

    Guo, Qinghai; Wang, Yanxin


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

  19. Coupled thermo-hydro-mechanical modeling of heat extraction from the Tattapani geothermal field, India (United States)

    Nand Pandey, Sachchida; Vishal, Vikram


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

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

    Directory of Open Access Journals (Sweden)

    Brian P. Hedlund


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

  1. Space-Time Evolution of Seismicity in North-Western Geysers Geothermal Field and its Connection to Stimulation Processes (United States)

    Leptokaropoulos, Konstantinos; Staszek, Monika; Lasocki, Stanislaw; Kwiatek, Grzegorz; Martinez-Garzon, Patricia


    The rising needs for energy along with the recent requirements for more efficient usage and exploitation of the deep underground have resulted to a growing scientific and public concern on related environmental impacts. Hydraulic fracturing that has been carried out during the last decades is occasionally connected with triggered and induced seismicity worldwide. Data from geothermal fields can be used as a proxy for shale gas exploitation associated seismicity since they are both tightly connected to hydraulic fracturing. For that reason we utilize 'The Geysers' data from the compiled SHEER (Shale Gas Exploration and Exploitation Induced Risks) database. The Geysers (California, USA) is the largest producing geothermal field in the world and has been sufficiently monitored and studied since the last decades. Seismic and technological data gathered during the past 40 years indicate a connection of seismic activity with the fluctuations of the injected fluid volume. In this study we verify and quantify this correlation by analyzing the data associated with 2 injection wells (Prati-9 and Prati-29) which covers a time period of approximately 7 years (from November 2007 to August 2014). The correlation between spatio-temporal seismicity evolution and variation of the injection data is performed by elaboration of original and smoothed time-series through specified statistical tools (cross correlation, binomial test to investigate significant rate changes, b-value variation). Our analysis indicate a short time delay of seismicity occurrence at distances larger than 200m from the injection well, whereas no evidence of significant correlation between injection rates and b-values was discovered. The obtained results are expected to contribute to a better comprehension of the role of hydraulic fracturing and the physical processes controlling seismogenesis in fluid injection sites. Acknowledgements: This work was supported within SHEER: "Shale Gas Exploration and

  2. Arsenic speciation and transport associated with the release of spent geothermal fluids in Mutnovsky field (Kamchatka, Russia)

    Energy Technology Data Exchange (ETDEWEB)

    Ilgen, Anastasia G.; Rychagov, Sergey N.; Trainor, Thomas P. (Alaska Fairbanks); (Russ. Acad. Sci.)


    The use of geothermal fluids for the production of electricity poses a risk of contaminating surface waters when spent fluids are discharged into (near) surface environments. Arsenic (As) in particular is a common component in geothermal fluids and leads to a degradation of water quality when present in mobile and bioavailable forms. We have examined changes in arsenic speciation caused by quick transition from high temperature reducing conditions to surface conditions, retention mechanisms, and the extent of transport associated with the release of spent geothermal fluids at the Dachny geothermal fields (Mutnovsky geothermal region), Kamchatka, Russia -- a high temperature field used for electricity production. In the spent fluids, the arsenic concentration reaches 9 ppm, while in natural hot springs expressed in the vicinity of the field, the As concentration is typically below 10 ppb. The aqueous phase arsenic speciation was determined using Liquid Chromatography (LC) coupled to an Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The arsenic speciation in the bottom sediments (< 65 {mu}m fraction) of the local surface waters was analyzed using X-ray Absorption Spectroscopy (XAS). Arsenic in the geothermal source fluids is predominantly found as As(III), while a mixture of As(III)/As(V) is found in the water and sediment of the Falshivaia River downstream from the power plant. The extent of elevated arsenic concentrations in water is limited by adsorption to the bottom sediment and dilution, as determined using Cl{sup -} from the deep well fluids as a tracer. Analysis of the Extended X-ray Absorption Fine Structure (EXAFS) spectra shows that sediment phase arsenic is associated with both Al- and Fe-rich phases with a bi-dentate corner sharing local geometry. The geothermal waste fluids released in the surface water create a localized area of arsenic contamination. The extent of transport of dissolved As is limited to {approx}7 km downstream from the source

  3. Anomalously High Geothermal Gradients in the Buckman Well Field, Santa Fe County, New Mexico (United States)

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


    Temperature as a function of depth was measured in ten wells in the Santa Fe, NM area as part of the Summer of Applied Geophysics Experience (SAGE) program. Eight of the wells are within 5.5 km of the city's Buckman municipal well field and two wells are at La Tierra, 16.5 km to the SE. Geothermal gradients increase from east to west towards the Buckman area, from 20°C/km at La Tierra to 76°C/km at Buckman. Within the Buckman well field, two wells on its eastern side were determined to have temperature gradients of 32°C/km and 42°C/km. Only 300 m west, the geothermal gradient sharply increases, and measured gradients reach 76 °C/km (well number SF4A), 62°C/km (SF4B), and 68°C/km (SF3A) in three shallow (geothermal anomaly. The short spatial wavelength of the horizontal gradient increase argues for a localized source. The unusually high gradients in three of the wells may be associated with fault-controlled, effective shallow-source, warm water upflow or with lateral flow in a shallow aquifer. On the regional level, the east to west increase in temperature gradients can be explained by deep circulating groundwater flow in the Espanola Basin and upwelling near the Rio Grande. Another possible explanation comes from gravity data gathered by SAGE over several years that shows a local NW-striking structural high in the area that could force localized convective upflow. Regional aeromag maps indicate magnetic lows exactly underneath the anomalous wells. These may be interpreted as buried volcanic plugs beneath the Buckman well field, acting as conduits for upwelling warmer waters. They may also indicate hydrothermally altered rock beneath the surface. A more nontraditional cause of the sharp thermal anomaly is also possible. The geothermal gradient anomaly coincides with the dramatic discovery by InSAR in 1993-2000 of localized ground subsidence due to excessive water well pumping. Sediment deformation as modeled in the upper 1 km could generate a local thermal

  4. Guidebook to Geothermal Finance

    Energy Technology Data Exchange (ETDEWEB)

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


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

  5. Optimization of Wellhead Piping Design for Production Wells at Development of Steam-Water Geothermal Fields

    Directory of Open Access Journals (Sweden)

    A.N. Shulyupin


    Full Text Available At present, the exploitation of geothermal resources develops in a fair competition with other types of energy resources. This leads to actuality of questions which associated with the more efficient use of existing wells, because cost of their drilling is a significant share of geothermal projects. In domestic practice of development of geothermal resources the steam-water wells have greatest energy potential. One way to improve the performance of these wells is a providing of smooth change of direction of motion of steam-water mixture from the vertical, in the well, to the horizontal, in steam gathering system. Typical wellhead piping of domestic steam-water wells involves the removal of the mixture through a cross bar at a right angle. Cross bar can generate considerable pressure loss that increases the operating pressure at the mouth of the well and reduces flow rate. It seems reasonable to substitute the typical cross bar by smooth pipe bend. This reduces wellhead resistance coefficient by more than on 2. Increase of curvature radius of pipe bend reduces the pressure loss to a local resistance but increases the friction pressure loss. There is an optimal curvature radius of pipe bend for minimum pressure loss in view of a local resistance and friction in the pipe bend. Calculations have shown that the optimum value for the radius of curvature is found in the range from 1.4 to 4.5 tube internal diameters. However, for technological reasons it is recommended to choose the radius of curvature from 1.4 to 2.4 diameters. Mounting of smooth pipe bend on the wellhead can provide significant economic benefits. For Mutnovka field (Kamchatka, this effect is estimated at 17.5 million rubles in year.

  6. Geothermal Potential of Marine Corps Air Station, Yuma, Arizona, and the Western Portion of Luke-Williams Gunnery Range (United States)


    Domes in the Northern Part of the Gulf of California," in Symposia on the Cerro Prieto Geothermal Field, Baja California, Mexico, Comision Federal de...Laboratory, August 1979. LA-7953-MS. 22 pp. 10. J. de Boer. "Paleomagnetism of the Quaternary Cerro Prieto , Crater Elegante, and Salton Buttes Volcanic...NWC TP 6827 S Geothermal Potential of Marine Corps Air Station, Yuma, Arizona, and the Western Portion of Luke-Williams Gunnery Range by Steven C

  7. Analysis and interpretation of stress indicators in deviated wells of the Coso Geothermal Field (United States)

    Schoenball, Martin; Glen, Jonathan M. G.; Davatzes, Nicholas C.


    Characterizing the tectonic stress field is an integral part of the development of hydrothermal systems and especially for enhanced geothermal systems (EGS). With a well characterized stress field the propensity of fault slip on faults with known location and orientation can be identified. Faults that are critically oriented for faulting with respect to the stress field are known to provide natural fluid pathways. A high slip tendency makes a fault a likely candidate for reactivation during the creation of an EGS. Similarly, the stress state provides insight for the potential of larger, damaging earthquakes should extensive portions of well-oriented, larger faults be reactivated.The analysis of stress indicators such as drilling-induced fractures and borehole breakouts is the main tool to infer information on the stress state of a geothermal reservoir. The standard procedure is applicable to sub-vertical wellbore sections and highly deviated sections have to be discarded. However, in order to save costs and reduce the environmental impact most recent wells are directionally drilled with deviations that require appropriate consideration of the deviated trajectory. Here we present an analysis scheme applicable to arbitrary well trajectories or a combination of wells to infer the stress state. Through the sampling of the stress tensor along several directions additional information on the stress regime and even relative stress magnitudes can be obtained. We apply this method on image logs from the pair of wells 58-10 and 58A-10 that were drilled from the same well pad. Both wells have image logs of about 2km of their trajectories that are separated by less than 300m. For both wells we obtain a mean orientation of SHmax of N23° with large standard deviations of locations of stress indicators of 24° and 26°, respectively. While the local stress direction is highly variable along both wells with dominant wavelengths from around 50 to 500m, the mean directions are very

  8. Variability of surface temperature in agricultural fields of central California (United States)

    Hatfield, J. L.; Millard, J. P.; Goettelman, R. C.


    In an attempt to evaluate the relationship between hand-held infrared thermometers and aircraft thermal scanners in near-level terrain and to quantify the variability of surface temperatures within individual fields, ground-based and aircraft thermal sensor measurements were made along a 50-km transect on 3 May 1979 and a 20-km transect on 7 August 1980. These comparisons were made on fields near Davis, California. Agreement was within 1 C for fields covered with vegetation and 3.6 C for bare, dry fields. The variability within fields was larger for bare, dry fields than for vegetatively covered fields. In 1980, with improvements in the collection of ground truth data, the agreement was within 1 C for a variety of fields.

  9. Resource investigation of low- and moderate-temperature geothermal areas in Paso Robles, California

    Energy Technology Data Exchange (ETDEWEB)

    Campion, L.F.; Chapman, R.H.; Chase, G.W.; Youngs, L.G.


    Ninety-eight geothermal wells and springs were identified and plotted, and a geologic map and cross sections were compiled. Detailed geophysical, geochemical, and geological surveys were conducted. The geological and geophysical work delineated the basement highs and trough-like depressions that can exercise control on the occurrence of the thermal waters. The Rinconada fault was also evident. Cross sections drawn from oil well logs show the sediments conforming against these basement highs and filling the depressions. It is along the locations where the sediments meet the basement highs that three natural warm springs in the area occur. Deep circulation of meteoric waters along faults seems to be a reasonable source for the warm water. The Santa Margarita, Pancho Rico, and Paso Robles Formations would be the first permeable zones that abut the faults through which water would enter. Temperatures and interpretation of well logs indicate the warmest aquifer at the base of the Paso Robles Formation. Warm water may be entering higher up in the section, but mixing with water from cooler zones seems to be evident. Geothermometry indicates reservoir temperatures could be as high as 91/sup 0/C (196/sup 0/F).

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  11. Irregular focal mechanisms observed at Salton Sea Geothermal Field: Possible influences of anthropogenic stress perturbations (United States)

    Crandall-Bear, Aren; Barbour, Andrew J.; Schoenball, Martin; Schoenball, Martin


    At the Salton Sea Geothermal Field (SSGF), strain accumulation is released through seismic slip and aseismic deformation. Earthquake activity at the SSGF often occurs in swarm-like clusters, some with clear migration patterns. We have identified an earthquake sequence composed entirely of focal mechanisms representing an ambiguous style of faulting, where strikes are similar but deformation occurs due to steeply-dipping normal faults with varied stress states. In order to more accurately determine the style of faulting for these events, we revisit the original waveforms and refine estimates of P and S wave arrival times and displacement amplitudes. We calculate the acceptable focal plane solutions using P-wave polarities and S/P amplitude ratios, and determine the preferred fault plane. Without constraints on local variations in stress, found by inverting the full earthquake catalog, it is difficult to explain the occurrence of such events using standard fault-mechanics and friction. Comparing these variations with the expected poroelastic effects from local production and injection of geothermal fluids suggests that anthropogenic activity could affect the style of faulting.

  12. A large and complete Jurassic geothermal field at Claudia, Deseado Massif, Santa Cruz, Argentina (United States)

    Guido, Diego M.; Campbell, Kathleen A.


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

  13. Plant adaptation to extreme environments: the example of Cistus salviifolius of an active geothermal alteration field. (United States)

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


    Cistus salviifolius is able to colonise one of the most extreme active geothermal alteration fields in terms of both soil acidity and hot temperatures. The analyses of morpho-functional and physiological characters, investigated in leaves of plants growing around fumaroles (G leaves) and in leaves developed by the same plants after transfer into growth chamber under controlled conditions (C leaves) evidenced the main adaptive traits developed by this pioneer plant in a stressful environment. These traits involved leaf shape and thickness, mesophyll compactness, stomatal and trichome densities, chloroplast size. Changes of functional and physiological traits concerned dry matter content, peroxide and lipid peroxidation, leaf area, relative water and pigment contents. A higher reducing power and antioxidant enzymatic activity were typical of G leaves. Though the high levels of stress parameters, G leaves showed stress-induced specific morphogenic and physiological responses putatively involved in their surviving in active geothermal habitats. Copyright © 2013 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  14. Geothermal implications of a refined composition-age geologic map for the volcanic terrains of southeast Oregon, northeast California, and southwest Idaho, USA (United States)

    Burns, Erick; Gannett, Marshall W.; Sherrod, David R.; Keith, Mackenzie; Curtis, Jennifer A.; Bartolino, James R.; Engott, John A.; Scandella, Benjamin P.; Stern, Michelle A.; Flint, Alan L.


    Sufficient temperatures to generate steam likely exist under most of the dominantly volcanic terrains of southeast Oregon, northeast California, and southeast Idaho, USA, but finding sufficient permeability to allow efficient advective heat exchange is an outstanding challenge. A new thematic interpretation of existing state-level geologic maps provides an updated and refined distribution of the composition and age of geologic units for the purposes of assessing the implications for measurement and development of geothermal resources. This interpretation has been developed to better understand geothermal and hydrologic resources of the region. Comparison of the new geologic categories with available hydrologic data shows that younger volcanogenic terrains tend to have higher primary permeability than older terrains. Decrease in primary permeability with age is attributable to weathering and hydrothermal alteration of volcanogenic deposits to pore-filling clays and deposition of secondary deposits (e.g., zeolites). Spring density as a function of geology and precipitation can be used to infer groundwater flow path length within the upper aquifers. Beneath the upper aquifers, we postulate that, due to accelerated hydrothermal alteration at temperatures ~>30 °C, primary permeability at depths of geothermal interest will be limited, and that secondary permeability is a more viable target for hydrothermal fluid withdrawal. Because open fractures resulting from tensile stresses will affect all geologic layers, regions with a significant amount of groundwater flow through shallow, structurally controlled secondary permeability may overlay zones of deep secondary permeability. Regardless of whether the shallow permeability is connected with the deep permeability, shallow groundwater flow can mask the presence of deep hydrothermal flow, resulting in blind geothermal systems. Ideally, hydraulic connectivity between shallow and deep secondary permeability is limited, so that

  15. Paleomagnetic Reorientation of Structural Elements in Drill Cores: an example from Tolhuaca Geothermal Field (United States)

    Perez-Flores, P.; Veloso, E. E.; Cembrano, J. M.; Sánchez, P.; Iriarte, S.; Lohmar, S.


    Reorientation of mesoscopic faults, veins and fractures recovered from drilling is critical to construct reliable structural models that can account for their architecture and deformation regime. However, oriented cores are expensive and time consuming to drill. Some techniques achieve reorientation by introducing tools into the borehole. Problems arise when boreholes are unstable or collapse. One alternative technique allowing reorientation is to obtain reliable paleomagnetic vectors to reorient each core piece after drilling. Here, we present stable and reliable remnant magnetic vectors calculated from the Tol-1 core to analyze the geometry of the fracture network and its relationship to regional tectonic. Tol-1 core is a vertical, 1073 m deep geothermal well, drilled at the Tolhuaca Geothermal Field in the Southern Volcanic Zone of the Andes by MRP Geothermal Chile Ltda (formerly GGE Chile SpA) in 2009. The core consists of basaltic/andesitic volcanic rocks with subordinate pyroclastic/volcaniclastic units, with probable Pleistocene age. Fault planes with slickenlines and mineral fiber kinematic indicators are common in the upper 700 m of the core. Calcite, quartz and calcite-quartz veins are recognized along of entire core, whereas epidote-quartz and calcite-epidote veins occur in the last 350 m, minor chlorite, anhydrite and clay-minerals are present. Orientations of structural features in the core were measured with a goniometer using the core's axis and a false north for each piece; hence, orientation data has a false strike but a real dip. To achieve total reorientation of the pieces, we collected 200 standard-size paleomagnetic specimens, ensuring that at least four of them were recovered from continuous pieces. Thermal (up to 700°C) and alternating field demagnetization (up to 90mT on steps of 2mT) methods were used to isolate a stable remnant magnetization (RM) vector, and each technique yielded similar results. RM vectors were recovered between 0 to 25

  16. Effects of geothermal energy utilization on stream biota and water quality at The Geysers, California. Final report. [Big Sulphur, Little Sulphur, Squaw, and Pieta Creeks

    Energy Technology Data Exchange (ETDEWEB)

    LeGore, R.S.


    The discussion is presented under the following section headings: biological studies, including fish, insects, and microbiology; stream hydrology; stream water quality, including methods and results; the contribution of tributaries to Big Sulphur Creek, including methods, results, and tributary characterization; standing water at wellheads; steam condensate quality; accidental discharges; trout spawning bed quality; major conclusions; list of references; and appendices. It is concluded that present operational practices at Geysers geothermal field do not harm the biological resources in adjacent streams. The only effects of geothermal development observed during the study were related to operational accidents. (JGB)

  17. Enhancement of subsurface geologic structure model based on gravity, magnetotelluric, and well log data in Kamojang geothermal field (United States)

    Yustin Kamah, Muhammad; Armando, Adilla; Larasati Rahmani, Dinda; Paramitha, Shabrina


    Geophysical methods such as gravity and magnetotelluric methods commonly used in conventional and unconventional energy exploration, notably for exploring geothermal prospect. They used to identify the subsurface geology structures which is estimated as a path of fluid flow. This study was conducted in Kamojang Geothermal Field with the aim of highlighting the volcanic lineament in West Java, precisely in Guntur-Papandayan chain where there are three geothermal systems. Kendang Fault has predominant direction NE-SW, identified by magnetotelluric techniques and gravity data processing techniques. Gravity techniques such as spectral analysis, derivative solutions, and Euler deconvolution indicate the type and geometry of anomaly. Magnetotelluric techniques such as inverse modeling and polar diagram are required to know subsurface resistivity charactersitics and major orientation. Furthermore, the result from those methods will be compared to geology information and some section of well data, which is sufficiently suitable. This research is very useful to trace out another potential development area.

  18. Accurate estimation of seismic source parameters of induced seismicity by a combined approach of generalized inversion and genetic algorithm: Application to The Geysers geothermal area, California (United States)

    Picozzi, M.; Oth, A.; Parolai, S.; Bindi, D.; De Landro, G.; Amoroso, O.


    The accurate determination of stress drop, seismic efficiency, and how source parameters scale with earthquake size is an important issue for seismic hazard assessment of induced seismicity. We propose an improved nonparametric, data-driven strategy suitable for monitoring induced seismicity, which combines the generalized inversion technique together with genetic algorithms. In the first step of the analysis the generalized inversion technique allows for an effective correction of waveforms for attenuation and site contributions. Then, the retrieved source spectra are inverted by a nonlinear sensitivity-driven inversion scheme that allows accurate estimation of source parameters. We therefore investigate the earthquake source characteristics of 633 induced earthquakes (Mw 2-3.8) recorded at The Geysers geothermal field (California) by a dense seismic network (i.e., 32 stations, more than 17.000 velocity records). We find a nonself-similar behavior, empirical source spectra that require an ωγ source model with γ > 2 to be well fit and small radiation efficiency ηSW. All these findings suggest different dynamic rupture processes for smaller and larger earthquakes and that the proportion of high-frequency energy radiation and the amount of energy required to overcome the friction or for the creation of new fractures surface changes with earthquake size. Furthermore, we observe also two distinct families of events with peculiar source parameters that in one case suggests the reactivation of deep structures linked to the regional tectonics, while in the other supports the idea of an important role of steeply dipping faults in the fluid pressure diffusion.

  19. Using geochemical and isotopic techniques for exploration of geothermal energy in Southern Sabalan geothermal field, NW Iran (United States)

    Masoumi, Rahim


    From a hydrogeochemical point of view the geothermal fluids in the study area can be divided into two categories, (1) Na-Cl and (2) Na-Ca-HCO3. In the study area, the hot water samples depict temperature and pH ranges of 22 °C to 77 °C and 6.4 to 7.3, respectively. The total dissolved solids vary from 456 mg/L to 7006 mg/L. The concentration of rare metallic and non-metallic elements such as Li, Rb, B, Ba, Sr, CS, Se, Al, As, Hg in cold and hot spring waters in the Bushdi area were also analyzed. The utmost concentration belongs to Se which ranges from 135 mg/L to 273 mg/L. Boron also shows notable concentration values, in most samples it exceeds 20 mg/L, and in certain samples it ranges from 28 mg/L to 33.5 mg/L. The concentration value of arsenic ranges from 3 mg/L to 4 mg/L. The maximum concentration value of mercury is 0.01 mg/L. The δ18O values of these samples vary from -12.4 ‰ to -7.5 ‰ and the δD values range from -78.6 ‰ to -70.6 ‰. Plotting δ18O versus δD demonstrates that the data points are clustered close to both, the global meteoric water line (GMWL) with the equation δD = 8 δ18O + 10 and, the national meteoric water line (NMWL) with the equation δD = 6.89 δ18O + 6.57. As can be observed, the geothermal fluids in the Bushdi area show relatively slight increase in δ18O values that may be caused by interaction of hot fluids with host volcanic rocks. In fact, this relatively slight increment in δ18O values may indicate the low to moderate temperature of the geothermal system. The δD values, in general, do not show notable variation because of very low hydrogen content of the host rocks. The slight increase in δD, however, may be in conjunction with vaporization and isotopic interaction with the host rocks. The 3H content of the cold and hot waters in the Bushdi area is relatively high and varies from 0.65 TU to 41.4 TU. This may be caused either by mixing with meteoric sources or rapid fluid flow within the system in a shorter time

  20. Geothermal Resource Verification for Air Force Bases, (United States)


    680OF (3600 C) in the Salton Sea, California, and the nearby Cerro Prieto region of Mexico. Liquid water can exist underground in nature to a maxi...northwest Mexico’s Cerro Prieto field and southcentral California’s Imperial Valley area [banwell (1970)]. The Baca field in New Mexico’s Jemez Mountains...AO-AIOQ bA SANDI NA IONCAL L AB NURU NNI 1/ GEOTHERMAL RESOURCE VER IFIC A FR AIR FORCE RASES, 1W UCJUN 81 P f GRANT DE-AC04-TAiDOpOos WACLASSIFIED


    Directory of Open Access Journals (Sweden)

    E. Ristin Pujiindiyati


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

  2. Testing for the ‘predictability’ of dynamically triggered earthquakes in Geysers Geothermal Field (United States)

    Aiken, Chastity; Meng, Xiaofeng; Hardebeck, Jeanne L.


    The Geysers geothermal field is well known for being susceptible to dynamic triggering of earthquakes by large distant earthquakes, owing to the introduction of fluids for energy production. Yet, it is unknown if dynamic triggering of earthquakes is ‘predictable’ or whether dynamic triggering could lead to a potential hazard for energy production. In this paper, our goal is to investigate the characteristics of triggering and the physical conditions that promote triggering to determine whether or not triggering is in anyway foreseeable. We find that, at present, triggering in The Geysers is not easily ‘predictable’ in terms of when and where based on observable physical conditions. However, triggered earthquake magnitude positively correlates with peak imparted dynamic stress, and larger dynamic stresses tend to trigger sequences similar to mainshock–aftershock sequences. Thus, we may be able to ‘predict’ what size earthquakes to expect at The Geysers following a large distant earthquake.

  3. Testing for the 'predictability' of dynamically triggered earthquakes in The Geysers geothermal field (United States)

    Aiken, Chastity; Meng, Xiaofeng; Hardebeck, Jeanne


    The Geysers geothermal field is well known for being susceptible to dynamic triggering of earthquakes by large distant earthquakes, owing to the introduction of fluids for energy production. Yet, it is unknown if dynamic triggering of earthquakes is 'predictable' or whether dynamic triggering could lead to a potential hazard for energy production. In this paper, our goal is to investigate the characteristics of triggering and the physical conditions that promote triggering to determine whether or not triggering is in anyway foreseeable. We find that, at present, triggering in The Geysers is not easily 'predictable' in terms of when and where based on observable physical conditions. However, triggered earthquake magnitude positively correlates with peak imparted dynamic stress, and larger dynamic stresses tend to trigger sequences similar to mainshock-aftershock sequences. Thus, we may be able to 'predict' what size earthquakes to expect at The Geysers following a large distant earthquake.

  4. Pressure changes and their effects on the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Bermejo M, F.J.; Navarro O, F.X.; Esquer P, C.A.; Castillo B, F.; de la Cruz D, F.C.


    Continuous extraction of the water-steam mixture at the field has been increasing to fulfill the steam requirements of the power plant. As a result, pressure declines have been observed in the producing strata in all of the wells, as well as in the geothermal reservoir as a whole. Anomalous behavior that has been observed in the wells' hydraulic columns in most cases is due to the interconnection of the various strata penetrated by the well. When this occurs, unbalanced hydraulic pressures cause the movement of fluids between the strata. As an example of this hydraulic imbalance causing the flow of fluids from an upper to a lower zone, well Nuevo Leon 1 where this effect occurs between regions 600 m apart was chosen.

  5. MT data modelling at Las Tres Virgenes, Baja California Sur, Mexico, geothermal zone. Modelado de datos magnetotelurgicos en el campo geotermico de Las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Palma Guzman, Sergio Hugo (Departamento de Exploracion, Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico))


    An interpretation of MT soundings at the Las Tres Virgenes, Baja California Sur, Mexico, geothermal project, was conducted, to actualize the geoelectric model of the reservoir, with the support provided by new drilling data. MT data were collected during the Comision Federal de Electricidad 1992 and 1994 campaigns. The use of apparent resistivity maps, tipper and apparent profiles lets us to identify TE and TM modes, as well as the lateral variations related to structural geology changes. These results were used to prepare sections based on Bostick inversion of TE mode of each sounding. Results were correlated to lithology reported by recent exploratory drilling. MT comprehensive studies let us delineate the reservoir limits, and the main geologic structures related to geothermal fluids production.

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

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


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

  7. Shallow hydrothermal regime of the East Brawley and Glamis known geothermal resource areas, Salton Trough, California

    Energy Technology Data Exchange (ETDEWEB)

    Mase, C.W.; Sass, J.H.; Brook, C.A.; Munroe, R.J.


    Thermal gradients and thermal conductivities were obtained in real time using an in situ heat-flow technique in 15 shallow (90 to 150 m) wells drilled between Brawley and Glamis in the Imperial Valley, Southern California. The in situ measurements were supplemented by follow-up conventional temperature logs in seven of the wells and by laboratory measurements of thermal conductivity on drill cuttings. The deltaic sedimentary material comprising the upper approx. 100 m of the Salton Trough generally is poorly sorted and high in quartz resulting in quite high thermal conductivities (averaging 2.0 Wm/sup -1/ K/sup -1/ as opposed to 1.2 to 1.7 for typical alluvium). A broad heat-flow anomaly with maximum of about 200 mWm/sup -2/ (approx. 5 HFU) is centered between Glamis and East Brawley and is superimposed on a regional heat-flow high in excess of 100 mWm/sup -2/ (> 2.5 HFU). The heat-flow high corresponds with a gravity maximum and partially with a minimum in electrical resistivity, suggesting the presence of a hydrothermal system at depth in this area.

  8. Numerical Studies of the Heat and Mass Transport in the Cerro Prieto Geothermal Field, Mexico (United States)

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


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

  9. The geothermal field of Denmark from borehole measurements and 3D numerical modelling (United States)

    Fuchs, Sven; Balling, Niels


    We present a 3D numerical crustal temperature model and analyze the present-day geothermal field of onshore Denmark, including parts of the Danish Basin, the northernmost part of the North German Basin and the Sorgenfrei-Tornquist Zone. An extensive analysis of borehole and well-log data on a basin scale is conducted to derive the model parameterization with a spatial distribution of rock thermal conductivity as well as new, regionally variable heat-flow values. A new structural geological model with lithological layers is provided by the Geological Survey of Denmark and Greenland (GEUS). Measured heat flow and borehole temperature observations (102 values from 47 wells) are used to constrain the modelling results in terms of calibration and validation. The prediction uncertainties between modelled and observed temperatures at deep borehole sites are small (rms = 1.3°C). For 22 deep boreholes, new values of terrestrial surface heat flow are derived ranging between 64 and 84 mW/m2 (mean of 77 ± 5 mW/m2) for the Danish Basin, between 60 and 95 mW/m2 (mean of 80 ± 10 mW/m2) for the very northern part of North German Basin, and between 63 and 66 mW/m2 (mean of 65 ± 2 mW/m2) in the Sorgenfrei-Tornquist Zone, respectively. Heat flow from the mantle is estimated to be between 31 and 39 mW/m2 (q1-q3; mean of 34 ± 7 mW/m2). Lateral temperature variations found by 3D modelling are caused by complex geological structures, like salt structures, lateral variations in the thickness of basin sediments or tectonic features. The variations in rock thermal conductivity associated with different lithological units generate significant variations in temperature gradients and heat flow. Major geothermal sandstone reservoirs show significantly different temperatures according to a large variation in reservoir depth and different thermal conductivity of overlying lithologies. For example, temperatures of the Gassum Formation, covering most of the Danish onshore areas, are within the

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

    Nukman, M.; Moeck, I.


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

  11. Preliminary report on the Northern California Power Agency's Notice of Intention to seek certification for NCPA Geothermal Project No. 2

    Energy Technology Data Exchange (ETDEWEB)


    This preliminary report on the Northern California Power Agency (NCPA) geothermal power plant proposal has been prepared pursuant to California Public Resources Code Sections 25510, 25512, and 25540. It presents the preliminary Findings of fact and Conclusions adopted by the Commission Committee assigned to conduct proceedings on the Notice. In addition, the report contains a description of the proposed project, a summary of the proceedings to date, and local, state, and Federal government agency comments on the proposal. Finally, the report presents the Committee's view of those issues that require further consideration in future proceedings on the Notice. Pursuant to Public Resources Code Sections 25512 and 25540, the report presents preliminary Findings and Conclusions on: (1) conformity to the forecast of statewide and service area electric power demands; (2) the degree to which the proposed site and facility conform with applicable local, regional, state and Federal standards, ordinances, and laws; and (3) the safety and reliability of the facility.

  12. The spatial economics of geothermal district energy in a small, low-density town: a case study of Mammoth Lakes, California

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, C.R.; Kuby, M.J. [Arizona State University, Tempe, AZ (United States). Dept. of Geography; Bloomquist, G. [Washington State University (United States). Energy Program


    This research focuses on the spatial economics of geothermal district energy (DE) systems that distribute hot fluids through a pipeline network to multiple thermal customers. We argue here that DE is held back by uncertainty about its economic feasibility when implemented in real places. DE works best with high urban densities, but in the US the best geothermal resources are in the less-populated west. Economic geography theory suggests that the optimal size of a DE firm's service area should depend on the trade-off between the economies of scale inherent in a large service area and the greater network development costs and heat loss involved in serving a large area. The HEATMAP software program developed by Washington State University was used to study the feasibility of numerous scenarios for a proposed DE system in Mammoth Lakes, California. Results indicate that the core area of the town is large enough, dense enough, and in close enough proximity to the resource for profitable DE development. Proposed ski village developments would increase the thermal load density and significantly enhance its ability to remain competitive with other fuels, even in pessimistic sensitivity analyses regarding geothermal heat input costs, public participation, and retro-fitting costs. (author)

  13. Multi-use geothermal-energy system with augmentation for enhanced utilization: a non-electric application of geothermal energy in Susanville, California. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Olson, G.K.; Benner-Drury, D.L.; Cunnington, G.R.


    A site specific engineering and economic study of multi-use, augmented geothermal space/water heating and cooling systems was completed. The overall benefits to the City of Susanville, in both the public and private sectors, of using low temperature (150/sup 0/F to 240/sup 0/F) geothermal resources are explored. Options considered, alone and in combination, include heat pumps, fossil-fuel peaking, user load balancing, and cascading from the geothermal system serving the public buildings into a private Park of Commerce development. A range of well temperatures, depths, flow rates, and drilling costs are considered to provide system cost sensitivities and to make the study more widely useful to other sites. A planned development is emphasized for ease of financing of expansion. A preliminary design of Phase A of a Susanville Public Building Energy System and a conceptual design of an integrated Park of Commerce, Phase I, are included. This system was designed for a 150/sup 0/F resource and can be used as a model for other communities with similar resource temperatures.

  14. Engineering geology of the Geysers Geothermal Resource Area, Lake, Mendocino, and Sonoma Counties, California. Special report 122

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, C.F.; Amimoto, P.Y.; Sherburne, R.W.; Slosson, J.E.


    Guidelines for the engineering geology assessment of The Geysers Geothermal Resource Area (GRA) are presented. Approximately 50 percent of the geothermal wells and some of the power plants are presently located on landslide areas. Several geothermal wells have failed, causing additional land instability, loss of energy resource, and unnecessary expense. Hazardous geologic conditions in the area are identified, and measures for mitigating those hazardous conditions are recommended. Such measures or other equally adequate measures should be considered for any proposed development activity in The Geysers area.

  15. Geothermal Program Review X: proceedings. Geothermal Energy and the Utility Market -- the Opportunities and Challenges for Expanding Geothermal Energy in a Competitive Supply Market

    Energy Technology Data Exchange (ETDEWEB)


    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.

  16. Geothermal Energy. (United States)

    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…

  17. Geothermal Program Review XVII: proceedings. Building on 25 years of Geothermal Partnership with Industry

    Energy Technology Data Exchange (ETDEWEB)



    The US Department of Energy's Office (DOE) of Geothermal Technologies conducted its annual Program Review XVII in Berkeley, California, on May 18--20, 1999. The theme this year was "Building on 25 Years of Geothermal Partnership with Industry". In 1974, Congress enacted Public Law 93-410 which sanctioned the Geothermal Energy Coordination and Management Project, the Federal Government's initial partnering with the US geothermal industry. The annual program review provides a forum to foster this federal partnership with the US geothermal industry through the presentation of DOE-funded research papers from leaders in the field, speakers who are prominent in the industry, topical panel discussions and workshops, planning sessions, and the opportunity to exchange ideas. Speakers and researchers from both industry and DOE presented an annual update on research in progress, discussed changes in the environment and deregulated energy market, and exchanged ideas to refine the DOE Strategic Plan for research and development of geothermal resources in the new century. A panel discussion on Climate Change and environmental issues and regulations provided insight into the opportunities and challenges that geothermal project developers encounter. This year, a pilot peer review process was integrated with the program review. A team of geothermal industry experts were asked to evaluate the research in progress that was presented. The evaluation was based on the Government Performance and Results Act (GPRA) criteria and the goals and objectives of the Geothermal Program as set forth in the Strategic Plan. Despite the short timeframe and cursory guidance provided to both the principle investigators and the peer reviewers, the pilot process was successful. Based on post review comments by both presenters and reviewers, the process will be refined for next year's program review.

  18. Integrated geophysical imaging of the Aluto-Langano geothermal field (Ethiopia). (United States)

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


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

  19. Fracture network, fluid pathways and paleostress at the Tolhuaca geothermal field (United States)

    Pérez-Flores, Pamela; Veloso, Eugenio; Cembrano, José; Sánchez-Alfaro, Pablo; Lizama, Martín; Arancibia, Gloria


    In this study, we examine the fracture network of the Tolhuaca geothermal system located in the Southern Andean volcanic zone that may have acted as a pathway for migration and ascent of deep-seated fluids under the far/local stress field conditions of the area. We collected the orientation, slip-data and mineralogical content of faults and veins recovered on a ca. 1000 m deep borehole (Tol-1) located in the NW-flank of the Tolhuaca volcano. Tol-1 is a non-oriented, vertical borehole that recovered relatively young (50°) dips. The EW-striking veins are compatible with the calculated local stress field whereas NE-striking veins are compatible with the regional stress field, the morphological elongation of volcanic centers, alignments of flank vents and dikes orientation. Our results demonstrate that the paleomagnetic methodology proved to be reliable and it is useful to re-orient vertical boreholes such as Tol-1. Furthermore, our data show that the bulk transpressional regional stress field has local variations to a tensional stress field within the NE-striking fault zone belonging to the Liquiñe-Ofqui Fault System, favoring the activation of both NW- and NE-striking pre-existent discontinuities, especially the latter which are favorably oriented to open under the prevailing stress field. The vertical σ1 and NS-trending subhorizontal σ3 calculated in the TGS promote the activation of EW-striking extensional veins and both NE and NW-striking hybrid faults, constituting a complex fluid pathway geometry of at least one kilometer depth.

  20. Imperial County geothermal development. Quarterly report, January 1-March 31, 1982

    Energy Technology Data Exchange (ETDEWEB)


    The activities of the Geothermal Office are reported including: important geothermal events, geothermal waste disposal, grant applications to the California Energy Commission, the planned geothermal development meeting, and other geothermal planning activities. The activities of the Geothermal Planner include processing of applications for geothermal permits, processing of environmental impact reports, and other geothermal planning activities. The progress on the VTN Corporation direct heat study is discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  2. Reservoir engineering report for the magma-SDG and E geothermal experimental site near the Salton Sea, California

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, R.C.


    A description of the Salton Sea geothermal reservoir is given and includes approximate fault locations, geology (lithology), temperatures, and estimates of the extent of the reservoir. The reservoir's temperatures and chemical composition are also reviewed. The flow characteristics are discussed after analyses of drillstem tests and extended well tests. The field production, reserves and depletion are estimated, and the effects of fractures on flow and depletion are discussed. The reservoir is believed to be separated into an ''upper'' and ''lower'' portion by a relatively thick and continuous shale layer. The upper reservoir is highly porous, with high permeability and productivity. The lower reservoir is at least twice as large as the upper but has much lower storativity and permeability in the rock matrix. The lower reservoir may be highly fractured, and its temperatures and dissolved solids are greater than those of the upper reservoir. The proven reserves of heat in the upper reservoir are about /sup 1///sub 4/ GW.yr (in the fluid) and /sup 1///sub 3/ GW.yr (in the rock). In the lower reservoir the proven reserves of heat are 5/sup 3///sub 4/ GW.yr (in the fluid) and 17 GW.yr (in the rock). Unproven reserves greatly exceed these numbers. Injection tests following well completion imply that hydraulic fracturing has taken place in two of the SDG and E wells and at least one other well nearby.

  3. Health and safety impacts of nuclear, geothermal, and fossil-fuel electric generation in California. Volume 9. Methodologies for review of the health and safety aspects of proposed nuclear, geothermal, and fossil-fuel sites and facilities

    Energy Technology Data Exchange (ETDEWEB)

    Nero, A.V.; Quinby-Hunt, M.S.


    This report sets forth methodologies for review of the health and safety aspects of proposed nuclear, geothermal, and fossil-fuel sites and facilities for electric power generation. The review is divided into a Notice of Intention process and an Application for Certification process, in accordance with the structure to be used by the California Energy Resources Conservation and Development Commission, the first emphasizing site-specific considerations, the second examining the detailed facility design as well. The Notice of Intention review is divided into three possible stages: an examination of emissions and site characteristics, a basic impact analysis, and an assessment of public impacts. The Application for Certification review is divided into five possible stages: a review of the Notice of Intention treatment, review of the emission control equipment, review of the safety design, review of the general facility design, and an overall assessment of site and facility acceptability.

  4. Analysis of the apiclutural industry in relation to geothermal development and agriculture in the Imperial Valley, Imperial County, California

    Energy Technology Data Exchange (ETDEWEB)

    Atkins, E.L.


    PART I: Continuous exposure to 30 ppB H/sub 2/S increased lifespan of caged worker honey bees, Apis mellifera L., 33%; whereas, bees exposed > 13 days to 100 ppB and 300 ppB H/sub 2/S the lifespan was shortened 32% and 51%, respectively, over unexposed bees; bees exposed > 15 days to a combination of 300 ppB H/sub 2/S + 50 ppM CO/sub 2/ the lifespan was shortened 4.4% more that 300 ppB H/sub 2/S alone. The mean temperature and/or relative humidity did not exert a direct effect on the hazard to bees. A continuous exposure to 300 ppB SO/sub 2/ was detrimental to caged worker honey bees; and, a mean temperature of 27.2/sup 0/C was 75.7% more toxic than the same dosage at 16.7/sup 0/C. Worker bee lifespans exposed to 300 ppB SO/sub 2/ at 16.7/sup 0/C were shortened 13.5% and 79%, respectively, compared to unexposed bees. Therefore, both dosage and temperature exert direct effects on the hazards to bees. PART II: The status of the apicultural industry in Imperial County, California, was outlined giving a short characterization of the area in relation to the apicultural industry. Agriculture utilizes 500,000 intensely farmed acres which generated a 11-year average income of $370 million. Over 40 agricultural commodities are produced. The apicultural industry is intimately involved in 25% of the total gross agricultural income. In addition, most of the flora growing in the desert community which comprises the remainder of the county are very important to honey bees by providing sustaining nectar and/or pollen for brood rearing. The bee foraged flora provides substantial bee forage when colonies are located outside of the agriculutral area. It is concluded that geothermal resource development in the Imperial Valley is contemplated to have minimal effects on the apicultural industry.

  5. Vertical distribution of potentially toxic elements in sediments impacted by intertidal geothermal hot springs (Bahia Concepcion, Gulf of California) (United States)

    Leal-Acosta, M. L.; Shumilin, E.


    The intertidal geothermal hot springs (GHS) in Bahia Concepcion, Gulf of California are the source of potentially toxic elements to the adjacent marine environment surrounded by mangroves trees. The anoxic sediments enriched in organic carbon accumulate As, Hg and other heavy metals that can be bioavailable for the biota. To know the vertical distribution of these elements the geochemistry of a short sediment core was carried out. It was collected in June, 2010 in the mangrove area near to GHS (1 m) during a low tide, pushing manually a polypropylene tube into the sediments. The extracted sediment core was cut with plastic knife on 1 cm thick sub-samples, stored in plastic bags and transported on ice to the laboratory. The major and trace elements contents were determinate by ICP-MS after total digestion with stronger acids (HClO4-HNO3-HCl-HF). Certificate reference materials were used for the quality control of the method obtaining good recoveries for most of the elements (80-105%). The sediment core had high maximum contents of CaCO3 (70%) and total organic carbon (12%). The concentration of Hg along the core ranges from 650 to 74300 mg kg-1 and had more than three orders of magnitude above the reference values of 40 mg kg-1 for the Upper Continental Crust (UCC)1. In contrast, As ranges from 12 to 258 mg kg-1 resulting in more than one order of magnitude respect to UCC1 (1.7 mg kg-1). Similar pattern result for Mn, Cu, Pb, and Zn with the maximum values of 3200 mg kg-1, 42 mg kg-1, 12.4 mg kg-1, 71 mg kg-1 respectively that coincide with the maximum for As at the same core depth (4 cm). The Ca, Li, Co, Sb, U, and Mg also show high contents in comparison with the UCC1reference values. The maximum contents of Mo and Cd coincide with maximum concentration of sulfur (2%) at 6 to 8 cm. The enrichment factor calculated using Al as normalizing element showed Cd (7-280), As (26-329) and Hg (23-1196) as highly enriched mainly in the first centimeters of the sediment core

  6. Response of the Los Azufres Geothermal Field to Four Years of 25 MW Wellhead Generation

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, P.; Ortiz, J.; Miranda, G.; Gallardo, M.


    Production and chemical data have been compiled and analyzed on a six-month averaged basis for the first four years of electric energy generation with five 5-MW wellhead generators at the Los Azufres geothermal field. The data were evaluated with respect to the extent of observable thermal drawdown of the reservoir from 25 MW of generation in relation to the estimated capacity of the field of several hundred megawatts of power. The analysis updates the previous one compiled after the first two years of continuous production, at which time the results indicated that differences in reservoir temperature estimated from geochemical thermometers and wellhead production data were not statistically significant based on the number of data and the standard deviations. Analysis of the data after four years of operation were made for the larger number of data and smaller standard deviations. The results review the adequacy of the sampling frequency and the reliability of the measurements from statistical t-Test of the means of the first and second two-year periods. 3 figs., 5 tabs., 20 refs.

  7. Remote triggering and numerical simulations of passing seismic waves at the Larderello-Travale Geothermal Field, Italy (United States)

    Fuchs, Florian; Lupi, Matteo; Saenger, Erik


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

  8. Development of geothermal field following the 2000 eruption of Usu volcano as revealed by ground temperature, resistivity and self-potential variations

    National Research Council Canada - National Science Library

    T. Mogi; N. Matsushima; S. Takakura; Y. Nishida; M. Saba


    .... We made repeated measurements of ground temperature, Self-Potential (SP) and electrical resistivity, in order to clarify the mechanism of development of the newly formed geothermal field on the fault zone...

  9. Wellbore and soil thermal simulation for geothermal wells: development of computer model and acquisition of field temperature data. Part I report

    Energy Technology Data Exchange (ETDEWEB)

    Wooley, G.R.


    A downhole thermal simulator has been developed to improve understanding of the high downhole temperatures that affect many design factors in geothermal wells. This development is documented and field temperature data presented for flowing and shut-in conditions.

  10. Reactive Chemical Transport Simulation to Study Geothermal Production with Mineral Recovery and Silica Scaling


    Xu, Tianfu; Pruess, Karsten; Pham, Minh; Klein, Christopher; Sanyal, Subir


    There are vast reserves of dissolved minerals in the hypersaline brines of geothermal fields in the Imperial Valley of California. Recovery of zinc from geothermal brines is being practiced in this area, and recovery of silica, manganese, silver, lead and lithium has been or is being considered. Therefore, the ability to model mineral recovery is very significant in terms of economic development and resource utilization. The reactive geochemical transport simulator TOUGHREACT has been used to...

  11. Pressure Profiles in Two-Phase Geothermal Wells: Comparison of Field Data and Model Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Ambastha, A.K.; Gudmundsson, J.S.


    Increased confidence in the predictive power of two-phase correlations is a vital part of wellbore deliverability and deposition studies for geothermal wells. Previously, the Orkiszewski (1967) set of correlations has been recommended by many investigators to analyze geothermal wellbore performance. In this study, we use measured flowing pressure profile data from ten geothermal wells around the world, covering a wide range of flowrate, fluid enthalpy, wellhead pressure and well depth. We compare measured and calculated pressure profiles using the Orkiszewski (1967) correlations.

  12. Geothermal life cycle assessment - part 3

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, J. L. [Argonne National Lab. (ANL), Argonne, IL (United States); Frank, E. D. [Argonne National Lab. (ANL), Argonne, IL (United States); Han, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Elgowainy, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, M. Q. [Argonne National Lab. (ANL), Argonne, IL (United States)


    A set of key issues pertaining to the environmental performance of geothermal electric power have been addressed. They include: 1) greenhouse gas emissions (GHG) from geothermal facilities, 2) the use of supercritical carbon dioxide (scCO2) as a geofluid for enhanced geothermal systems (EGS), 3) quantifying the impact of well field exploration on the life cycle of geothermal power, and finally 4) criteria pollutant emissions for geothermal and other electric power generation. A GHG emission rate (g/kWh) distribution as function of cumulative running capacity for California has been developed based on California and U. S. government data. The distribution is similar to a global distribution for compared geothermal technologies. A model has been developed to estimate life cycle energy of and CO2 emissions from a coupled pair of coal and EGS plants, the latter of which is powered by scCO2 captured from coal plant side. Depending on the CO2 capture rate on the coal side and the CO2 consumption rate on the EGS side, significant reductions in GHG emissions were computed when the combined system is compared to its conventional coal counterpart. In effect, EGS CO2 consumption acts as a sequestration mechanism for the coal plant. The effects CO2 emissions from the coupled system, prompt on the coal side and reservoir leakage on the EGS side, were considered as well as the subsequent decline of these emissions after entering the atmosphere over a time frame of 100 years. A model was also developed to provide better estimates of the impact of well field exploration on the life cycle performance of geothermal power production. The new estimates increase the overall life cycle metrics for the geothermal systems over those previously estimated. Finally, the GREET model has been updated to include the most recent criteria pollutant emissions for a range of renewable (including geothermal) and other power

  13. Geothermal energy and the utility market -- the opportunities and challenges for expanding geothermal energy in a competitive supply market: Proceedings

    Energy Technology Data Exchange (ETDEWEB)


    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.

  14. Behavior of Rare Earth Element In Geothermal Systems; A New Exploration/Exploitation Tool

    Energy Technology Data Exchange (ETDEWEB)

    Scott A. Wood


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  16. Isotopic composition of waters from the El Tatio geothermal field, Northern Chile

    Energy Technology Data Exchange (ETDEWEB)

    Giggenbach, W.F.


    On the basis of isotopic and chemical analyses of 45 spring, well and meteoric water samples from the El Tatio geothermal field in Northern Chile, four main processes giving rise to the formation of a wide range of thermal discharges can be distinguished. (1) Deep dilution of a predominant, primary high chloride (5500 mg/l, 260/sup 0/) supply water derived from precipitation some 15 km east of El Tatio with local groundwater produces a secondary chloride water. (4750 mg/l, 190/sup 0/) feeding springs over a limited area. (2) Single step steam separation from these two waters leads to isotopic shifts and increases in chloride contents to 8000 and 6000 mg/l respectively. (3) Absorption of this separated steam and carbon dioxide into local ground water and mixing with chloride waters at shallow levels produces a series of intermediate temperature (160/sup 0/), low chloride, high bicarbonate waters. (4) Absorption of steam containing H/sub 2/S into surface waters leads to the formation of zero chloride, high sulfate waters; the isotopic enrichment observed is governed by a kinetic, steady state evaporation process.

  17. Arsenic speciation in sinter mineralization from a hydrothermal channel of El Tatio geothermal field, Chile (United States)

    Alsina, Marco A.; Zanella, Luciana; Hoel, Cathleen; Pizarro, Gonzalo E.; Gaillard, Jean-François; Pasten, Pablo A.


    El Tatio geothermal field is the principal natural source of arsenic for the Loa River, the main surface water resource in the hyper-arid Atacama Desert (Antofagasta Region, Northern Chile). Prior investigations by bulk X-ray absorption spectroscopy have identified hydrous ferric oxides as the principal arsenic-containing phase in sinter material from El Tatio, suggesting sorption as the main mechanism for arsenic scavenging by the solid phases of these hot spring environments. Here we examine siliceous sinter material sampled from a hydrothermal channel using synchrotron based X-ray micro-probe techniques, including As and Fe Kα X-ray fluorescence (μ-XRF), As K-edge X-ray absorption near edge structure (μ-XANES), and X-ray diffraction (μ-XRD). Least-squares linear fitting of μ-XANES spectra shows that arsenic is predominantly present as arsenate sorbed on hydrous ferric oxides (63% molar proportion), but we also identify nodular arsenide micro-mineralizations (37% molar proportion) similar to loellingite (FeAs2), not previously detected during bulk-scale analysis of the sinter material. Presence of arsenide mineralizations indicates development of anoxic environments on the surface of the siliceous sinter, and suggests a more complex biogeochemistry for arsenic than previously observed for circum-neutral pH brine hot spring environments.

  18. The impact of temperature on microbial diversity and AOA activity in the Tengchong Geothermal Field, China (United States)

    Li, Haizhou; Yang, Qunhui; Li, Jian; Gao, Hang; Li, Ping; Zhou, Huaiyang


    Using a culture-independent method that combines CARD-FISH, qPCR and 16S rDNA, we investigated the abundance, community structure and diversity of microbes along a steep thermal gradient (50-90 °C) in the Tengchong Geothermal Field. We found that Bacteria and Archaea abundance changed markedly with temperature changes and that the number of cells was lowest at high temperatures (90.8 °C). Under low-temperature conditions (52.3-74.6 °C), the microbial communities were dominated by Bacteria, which accounted for 60-80% of the total number of cells. At 74.6 °C, Archaea were dominant, and at 90.8 °C, they accounted for more than 90% of the total number of cells. Additionally, the microbial communities at high temperatures (74.6-90.8 °C) were substantially simpler than those at the low-temperature sites. Only a few genera (e.g., bacterial Caldisericum, Thermotoga and Thermoanaerobacter, archaeal Vulcanisaeta and Hyperthermus) often dominated in high-temperature environments. Additionally, a positive correlation between Ammonia-Oxidizing Archaea (AOA) activity and temperature was detected. AOA activity increased from 17 to 52 pmol of NO2- per cell d-1 with a temperature change from 50 to 70 °C.

  19. The Galapagos Spreading Centre at 86o W: a detailed geothermal field study. (United States)

    Green, K.E.; Von Herzen, R. P.; Williams, D.L.


    We report here measurements of the heat flow field of the Galapagos Spreading Center on crust of age less than 1.0 m.y. The 443 measurements in an area of about 570 km2 reveal the general planform of the geothermal flux and permit the first truly areal estimate of the near-axis conductive heat flux. The intrusion process and associated hydrothermal circulation dominate the surface heat flow pattern, with circulation apparently continuing beyong the limits of our survey. The areal average of the conductive heat flux is 7.1+-0.8 HFU (295+-33 m W/m2), about one-third the heat flux predicted by plate models. The remaining heat is apparently removed by venting of hydrothermal waters at the spreading axis and through basalt outcrops and hydrothermal mounds off axis. The pattern of surface heat flux is lineated parallel to the axis and the strongly lineated topography. Sharp lateral gradients in the heat flow, greater than 10 HFU/km near escarpments and commonly expressed as high heat flow at the tops of the scarps and lower heat flow in the valleys, may indicate a local concentration of the circulation by surface fault systems and/or variable sediment thickness. -Authors

  20. Monitoring Heat Losses Using Landsat ETM + Thermal Infrared Data: a Case Study in Unzen Geothermal Field, Kyushu, Japan (United States)

    Mia, Md. Bodruddoza; Bromley, Chris J.; Fujimitsu, Yasuhiro


    The Unzen geothermal field, our study area, is situated in the Shimabara Peninsula of Kyushu Island in Japan and is an area of active fumaroles.. Our prime objectives were (1) to estimate radiative heat flux (RHF), (2) to calculate approximately the heat discharge rate (HDR) using the relationship of RHF with the total heat loss derived from two geothermal field studies, and (3) finally, to monitor RHF as well as HDR in our study area using seven sets of Landsat 7 ETM + images from 2000 to 2009. We used the normalized differential vegetation index (NDVI) method for spectral emissivity estimation, the mono-window algorithm for land surface temperature (LST), and the Stefan-Boltzmann equation analyzing those satellite TIR images for RHF. We estimated that the maximum RHF was about 251 W/m2 in 2005 and minimum was about 27 W/m2 in 2001. The highest total RHF was about 39.1 MW in 2005 and lowest was about 12 MW in 2001 in our study region. We discovered that the estimated RHF was about 15.7 % of HDR from our studies. We applied this percentage to estimate HDR in Unzen geothermal area. The monitoring results showed a single fold trend of HDR from 2000 to 2009 with highest about 252 MW in 2005 and lowest about 78 MW in 2001. In conclusion, TIR remote sensing is thought as the best option for monitoring heat losses from fumaroles with high efficiency and low cost.

  1. Effect of variable frequency electromagnetic field on deposit formation in installations with geothermal water in Sijarinjska spa (Serbia

    Directory of Open Access Journals (Sweden)

    Stojiljković Dragan T.


    Full Text Available In this paper we have examined the effect of variable frequency electromagnetic field generated with a homemade device on deposit formation in installations with geothermal water from Sijarinjska Spa. The frequency alteration of the electromagnetic field in time was made by means of the sinusoidal and saw-tooth function. In laboratory conditions, with the flow of geothermal water at 0.015 l/s and temperature of 60 °C for 6 hours through a zig-zag glass pipe, a multiple decrease of total deposit has been achieved. By applying the saw-tooth and sinusoidal function, the decrease in contents of calcium and deposit has been achieved by 8 and 6 times, respectively. A device was also used on geothermal water installation in Sijarinjska Spa (Serbia, with the water flow through a 1'' diameter non-magnetic prochrome pipe at 0.15 l/s and temperature of 75 °C in a ten-day period. A significant decrease in total deposit and calcium in the deposit has also been achieved.

  2. Report on dipole-dipole resistivity and technology transfer at the Ahuachapan Geothermal field Ahuachapan, El Salvador

    Energy Technology Data Exchange (ETDEWEB)

    Fink, J.B. (Geophynque International, Tucson, AZ (United States))


    The Ahuachapan Geothermal Field (AGF) is a 90 megawatt geothermal-sourced powerplant operated by the Comision Ejecutiva Hidroelectrica del Rio Lempa (CEL) of El Salvador. During the period November 1987 through May 1988 a deep resistivity survey and technology transfer was performed at the AGF at the request of Los Alamos National Laboratory (LANL) as part of a United States Agency for International Development (USAID) project. The resistivity surveying is ongoing at the time of this report under the supervision of CEL personnel. LANL and contract personnel were present at the site during performance of the initial surveying for the purpose of technology transfer. This report presents the results and interpretation of the two initial resistivity survey lines performed on site during and shortly after the technology transfer period.

  3. SolGeo. A new computer program for solute geothermometers and its application to Mexican geothermal fields

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Surendra P.; Pandarinath, Kailasa; Santoyo, Edgar [Departamento de Sistemas Energeticos, Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Priv. Xochicalco s/no., Col Centro, A.P. 34, Temixco, Mor. 62580 (Mexico)


    The freely available computer program Solute Geothermometers (SolGeo) was written and tested using geochemical data and reported geothermometric temperatures from several geothermal wells from around the world. Subsurface temperatures for the Mexican geothermal fields of Cerro Prieto, Las Tres Virgenes, Los Azufres, and Los Humeros were estimated based on different solute geothermometers and found to be generally in close agreement with measured well temperatures when considering errors in the calculations and measurements. For Los Humeros wells it was concluded that a better agreement of chemical geothermometric temperatures is observed with static formation than with bottom-hole temperatures (BHTs). It was also found that the widely used Na-K geothermometric equations generally give more consistent and more reliable temperature estimates than the other geothermometers, which should therefore be applied with caution. (author)

  4. Geothermal Energy. (United States)

    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)…

  5. Simulation studies for wells AH-4bis/AH-17 and AH-18, Ahuachapan Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Monterrosa, Manuel Ernesto


    Well AH-4bis, at the Ahuachapan Geothermal Field is planned to be drilled on the same pad as the former AH-4. A simulation study was carried out for two casing dameters 13 5/8 and 9 5/8” in order to estimate its production and to know its economic feasibility. The simulation results indcate a high probability of production in the range of 7 Mwe, equivalent to 120 kg/s total mass flow rate, 1250 kJ/kg at 6 bar-a for the new well AH-4bis. Well AH- 17 is good producer, during 1991 after ten years of production, the well was shut-in due to silica scaling problems. A wellbore simulation was carried out in order to predict the new production conditions after the work-over, mainly to estimate the water flow rate in order to reduce the silica scaling. The results indicate a very low water flow rate. The match between the simulated and measured production curves after the work-over was successful. The well AH-18 is located at the southern part of the actual bore field. CEL is planning to expand the borefield at this area and it is neccessary to estimate the possible production condtions at that zone. The results indicate a high probabilty of production at that area. The power potential is estimated at 3.5 Mwe per well at WHP 6 bar-a and the wells will not require induction.

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

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, C.


    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)

  7. Monitoring the hydrologic system for potential effects of geothermal and ground-water development in the Long Valley caldera, Mono County, California, U.S.A. (United States)

    Farrar, C.D.; Lyster, D. L.


    In the early 1980's, renewed interest in the geothermal potential of the Long Valley caldera, California, highlighted the need to balance the benefits of energy development with the established recreational activities of the area. The Long Valley Hydrologic Advisory Committee, formed in 1987, instituted a monitoring program to collect data during the early stages of resource utilization to evaluate potential effects on the hydrologic system. Early data show declines in streamflow, spring flow, and ground-water levels caused by 6 years of below-average precipitation. Springs in the Hot Creek State Fish Hatchery area discharge water that is a mixture of nonthermal and hydrothermal components. Possible sources of nonthermal water have been identified by comparing deuterium concentrations in streams and springs. The equivalent amount of undiluted thermal water discharged from the springs was calculated on the basis of boron and chloride concentrations. Quantifying the thermal and nonthermal fractions of the total flow may allow researchers to assess changes in flow volume or temperature of the springs caused by groundwater or geothermal development.

  8. An integrated deep electrical resistivity model of the Larderello geothermal field (Italy) (United States)

    Rizzo, Enzo; Capozzoli, Luigi; De martino, Gregory; Godio, Alberto; Manzella, Adele; Perciante, Felice; Santilano, Alessandro


    A new deep electrical resistivity acquisition was carried out in Larderello geothermal area (Tuscania Region, Italy) by 3D Deep Electrical Resistivity Tomography (3D-DERT) and Magnetotelluric (M) acquisition. The investigated area is located close the Venelle2 well in the southern part of Larderello site, where there is the oldest field in the world under exploitation for power production (actual installed capacity is about 795 MWe). A vapour-dominated system is exploited to depth over 3500 m, with temperatures exceeding 350°C, from two different reservoirs. The Larderello area has been investigated by many geological and geophysical data of previous exploration projects but nowadays several critical issues on deep features of the field are still matter of debate, e.g., permeability distribution in the hydrothermal reservoir and the presence of fluids at supercritical condition at depth. The 3D-DERT system was designed by Surface-Surface and Surface-Hole electrode distributions in the area around Venelle2 well covering an area around 16km2. The well (kindly provided by Enel GP) was accessible down to 1.6 km with a temperature up to 250°C and a metallic casing down to 1 km. The in-hole thermal cable is characterized by n.12 flexible metallic electrodes with an electrodes space of 50m covering the open-hole portion (1050m-1600m). The surface electrodes are located around the Venelle2 hole on n.23 different positions connected to automatic dataloger to acquire the drop of potential and to transmitter device to inject the current (5-10A). The crucial task was the data processing, considering the large distance between the Tx and Rx systems that strongly reduces the signal to-noise ratio. To overcome this drawback, for each quadripole position the corresponding voltage signal was filtered, stored and processed with advanced statistical packages. The new 22 station were installed in the studied area and the data were carried out taking in account a permanent remote

  9. Geothermal Direct Heat Applications Program Summary

    Energy Technology Data Exchange (ETDEWEB)



    Because of the undefined risk in the development and use of geothermal energy as a thermal energy source, the Department of Energy Division of Geothermal Energy solicited competitive proposals for field experiments in the direct use of geothermal energy. Twenty-two proposals were selected for cost-shared funding with one additional project co-funded by the State of New Mexico. As expected, the critical parameter was developing a viable resource. So far, of the twenty resources drilled, fourteen have proved to be useful resources. These are: Boise, Idaho; Elko heating Company in Nevada; Pagosa Springs, Colorado; Philip School, Philip, South Dakota; St. Mary's Hospital, Pierre, South Dakota; Utah Roses near Salt Lake City; Utah State Prison, Utah; Warm Springs State Hospital, Montana; T-H-S Hospital, Marlin, Texas; Aquafarms International in the Cochella Valley, California; Klamath County YMCA and Klamath Falls in Oregon; Susanville, California and Monroe, utah. Monroe's 164 F and 600 gpm peak flow was inadequate for the planned project, but is expected to be used in a private development. Three wells encountered a resource insufficient for an economical project. These were Madison County at Rexburg, Idaho; Ore-Ida Foods at Ontario, Oregon and Holly Sugar at Brawley, California. Three projects have yet to confirm their resource. The Navarro College well in Corsicana, Texas is being tested; the Reno, Moana, Nevada well is being drilled and the El Centro, California well is scheduled to be drilled in January 1982. The agribusiness project at Kelly Hot Springs was terminated because a significant archeological find was encountered at the proposed site. The Diamond Ring Ranch in South Dakota, and the additional project, Carrie Tingley Hospital in Truth or Consequences, New Mexico both used existing wells. The projects that encountered viable resources have proceeded to design, construct, and in the most advanced projects, to operate geothermal systems for

  10. Geothermal handbook. Geothermal project, 1976. [Ecological effects of geothermal resources development

    Energy Technology Data Exchange (ETDEWEB)


    The geothermal program of Fish and Wildlife Service, U.S. Dept. of Interior, aims to develop ecologically sound practices for the exploration, development, and management of geothermal resources and the identification of the biological consequences of such development so as to minimize adverse effects on fish and wildlife resources. This handbook provides information about the ecological effects of geothermal resource development. Chapters are included on US geothermal resources; geothermal land leasing; procedures for assessing the effects on fish and game; environmental impact of exploratory and field development operations; and wildlife habitat improvement methods for geothermal development.

  11. Assessment of the Appalachian Basin Geothermal Field: Combining Risk Factors to Inform Development of Low Temperature Projects (United States)

    Smith, J. D.; Whealton, C.; Camp, E. R.; Horowitz, F.; Frone, Z. S.; Jordan, T. E.; Stedinger, J. R.


    Exploration methods for deep geothermal energy projects must primarily consider whether or not a location has favorable thermal resources. Even where the thermal field is favorable, other factors may impede project development and success. A combined analysis of these factors and their uncertainty is a strategy for moving geothermal energy proposals forward from the exploration phase at the scale of a basin to the scale of a project, and further to design of geothermal systems. For a Department of Energy Geothermal Play Fairway Analysis we assessed quality metrics, which we call risk factors, in the Appalachian Basin of New York, Pennsylvania, and West Virginia. These included 1) thermal field variability, 2) productivity of natural reservoirs from which to extract heat, 3) potential for induced seismicity, and 4) presence of thermal utilization centers. The thermal field was determined using a 1D heat flow model for 13,400 bottomhole temperatures (BHT) from oil and gas wells. Steps included the development of i) a set of corrections to BHT data and ii) depth models of conductivity stratigraphy at each borehole based on generalized stratigraphy that was verified for a select set of wells. Wells are control points in a spatial statistical analysis that resulted in maps of the predicted mean thermal field properties and of the standard error of the predicted mean. Seismic risk was analyzed by comparing earthquakes and stress orientations in the basin to gravity and magnetic potential field edges at depth. Major edges in the potential fields served as interpolation boundaries for the thermal maps (Figure 1). Natural reservoirs were identified from published studies, and productivity was determined based on the expected permeability and dimensions of each reservoir. Visualizing the natural reservoirs and population centers on a map of the thermal field communicates options for viable pilot sites and project designs (Figure 1). Furthermore, combining the four risk

  12. Direct use applications of geothermal resources at Desert Hot Springs, California. Final report, May 23, 1977--July 31, 1978. Volume II: appendixes

    Energy Technology Data Exchange (ETDEWEB)

    Christiansen, C.C.


    The following appendixes are included: Desert Hot Springs (DHS) Geothermal Project Advisory Board, Geothermal Citizens Advisory Committee, community needs assessment, geothermal resource characterization, a detailed discussion of the geothermal applications considered for DHS, space/water heating, agricultural operations, detailed analysis of a geothermal aquaculture facility, detailed discussion of proposed energy cascading systems for DHS, regulatory requirements, environmental impact assessment, resource management plan, and geothermal resources property rights and powers of cities to regulate indigenous geothermal resources and to finance construction of facilities for utilization of such resources. (MHR)

  13. Magmatic-like fluid source of the Chingshui geothermal field, NE Taiwan evidenced by carbonate clumped-isotope paleothermometry (United States)

    Lu, Yi-Chia; Song, Sheng-Rong; Wang, Pei-Ling; Wu, Chung-Che; Mii, Horng-Sheng; MacDonald, John; Shen, Chuan-Chou; John, Cédric M.


    The Chingshui geothermal field, a moderate-temperature and water-dominated hydrothermal system, was the site of the first geothermal power plant in Taiwan. Many geological, geophysical and geochemical studies using more than 21 drilled wells have been performed since the 1960s. However, there are still controversies regarding the heat and fluid sources due to the tectonically complicated geological setting. To clarify the heat and fluid sources, we analyzed clumped isotopes with carbon and oxygen isotopic compositions of calcite scaling in geothermal wells and veins on outcrops and calculated the δ18O values of the source fluids. Two populations of δ18O values were calculated: -5.8 ± 0.8‰ VSMOW from scaling in the well and -1.0 ± 1.6‰ to 10.0 ± 1.3‰ VSMOW from outcropping calcite veins, indicative of meteoric and magmatic fluid sources, respectively. Meanwhile, two hydrothermal reservoirs at different depths have been identified by magnetotelluric (MT) imaging with micro-seismicity underneath this area. As a result, we propose a two-reservoir model: the shallow reservoir provides fluids from meteoric water for the scaling sampled from wells, whereas the deep reservoir provides magmatic fluids from deep marble decarbonization recorded in outcropping calcite veins.

  14. Environmental summary document for the Republic Geothermal, Inc. application for a geothermal loan guaranty project: 64 MW well field and 48 MW (net) geothermal power plant

    Energy Technology Data Exchange (ETDEWEB)

    Layton, D.W.; Powers, D.J.; Leitner, P.; Crow, N.B.; Gudiksen, P.H.; Ricker, Y.E.


    A comprehensive review and analysis is provided of the environmental consequences of (1) guaranteeing a load for the completion of the 64 MW well field and the 48 MW (net) power plant or (2) denying a guaranteed load that is needed to finish the project. Mitigation measures are discussed. Alternatives and their impacts are compared and some discussion is included on unavoidable adverse impacts. (MHR)

  15. Natural or Induced: Identifying Natural and Induced Swarms from Pre-production and Co-production Microseismic Catalogs at the Coso Geothermal Field (United States)

    Schoenball, Martin; Kaven, Joern; Glen, Jonathan M. G.; Davatzes, Nicholas C.


    Increased levels of seismicity coinciding with injection of reservoir fluids have prompted interest in methods to distinguish induced from natural seismicity. Discrimination between induced and natural seismicity is especially difficult in areas that have high levels of natural seismicity, such as the geothermal fields at the Salton Sea and Coso, both in California. Both areas show swarm-like sequences that could be related to natural, deep fluid migration as part of the natural hydrothermal system. Therefore, swarms often have spatio-temporal patterns that resemble fluid-induced seismicity, and might possibly share other characteristics. The Coso Geothermal Field and its surroundings is one of the most seismically active areas in California with a large proportion of its activity occurring as seismic swarms. Here we analyze clustered seismicity in and surrounding the currently produced reservoir comparatively for pre-production and co-production periods. We perform a cluster analysis, based on the inter-event distance in a space-time-energy domain to identify notable earthquake sequences. For each event j, the closest previous event i is identified and their relationship categorized. If this nearest neighbor’s distance is below a threshold based on the local minimum of the bimodal distribution of nearest neighbor distances, then the event j is included in the cluster as a child to this parent event i. If it is above the threshold, event j begins a new cluster. This process identifies subsets of events whose nearest neighbor distances and relative timing qualify as a cluster as well as a characterizing the parent-child relationships among events in the cluster. We apply this method to three different catalogs: (1) a two-year microseismic survey of the Coso geothermal area that was acquired before exploration drilling in the area began; (2) the HYS_catalog_2013 that contains 52,000 double-difference relocated events and covers the years 1981 to 2013; and (3) a


    Energy Technology Data Exchange (ETDEWEB)

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


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

  17. Composition and origin of rhyolite melt intersected by drilling in the Krafla geothermal field, Iceland (United States)

    Zierenberg, R.A.; Schiffman, P.; Barfod, G.H.; Lesher, C.E.; Marks, N.E.; Lowenstern, Jacob B.; Mortensen, A.K.; Pope, E.C.; Bird, D.K.; Reed, M.H.; Friðleifsson, G.O.; Elders, W.A.


    The Iceland Deep Drilling Project Well 1 was designed as a 4- to 5-km-deep exploration well with the goal of intercepting supercritical hydrothermal fluids in the Krafla geothermal field, Iceland. The well unexpectedly drilled into a high-silica (76.5 % SiO2) rhyolite melt at approximately 2.1 km. Some of the melt vesiculated while extruding into the drill hole, but most of the recovered cuttings are quenched sparsely phyric, vesicle-poor glass. The phenocryst assemblage is comprised of titanomagnetite, plagioclase, augite, and pigeonite. Compositional zoning in plagioclase and exsolution lamellae in augite and pigeonite record changing crystallization conditions as the melt migrated to its present depth of emplacement. The in situ temperature of the melt is estimated to be between 850 and 920 °C based on two-pyroxene geothermometry and modeling of the crystallization sequence. Volatile content of the glass indicated partial degassing at an in situ pressure that is above hydrostatic (~16 MPa) and below lithostatic (~55 MPa). The major element and minor element composition of the melt are consistent with an origin by partial melting of hydrothermally altered basaltic crust at depth, similar to rhyolite erupted within the Krafla Caldera. Chondrite-normalized REE concentrations show strong light REE enrichment and relative flat patterns with negative Eu anomaly. Strontium isotope values (0.70328) are consistent with mantle-derived melt, but oxygen and hydrogen isotope values are depleted (3.1 and −118 ‰, respectively) relative to mantle values. The hydrogen isotope values overlap those of hydrothermal epidote from rocks altered by the meteoric-water-recharged Krafla geothermal system. The rhyolite melt was emplaced into and has reacted with a felsic intrusive suite that has nearly identical composition. The felsite is composed of quartz, alkali feldspar, plagioclase, titanomagnetite, and augite. Emplacement of the rhyolite magma has resulted in partial melting of

  18. Causality between expansion of seismic cloud and maximum magnitude of induced seismicity in geothermal field (United States)

    Mukuhira, Yusuke; Asanuma, Hiroshi; Ito, Takatoshi; Häring, Markus


    Occurrence of induced seismicity with large magnitude is critical environmental issues associated with fluid injection for shale gas/oil extraction, waste water disposal, carbon capture and storage, and engineered geothermal systems (EGS). Studies for prediction of the hazardous seismicity and risk assessment of induced seismicity has been activated recently. Many of these studies are based on the seismological statistics and these models use the information of the occurrence time and event magnitude. We have originally developed physics based model named "possible seismic moment model" to evaluate seismic activity and assess seismic moment which can be ready to release. This model is totally based on microseismic information of occurrence time, hypocenter location and magnitude (seismic moment). This model assumes existence of representative parameter having physical meaning that release-able seismic moment per rock volume (seismic moment density) at given field. Seismic moment density is to be estimated from microseismic distribution and their seismic moment. In addition to this, stimulated rock volume is also inferred by progress of microseismic cloud at given time and this quantity can be interpreted as the rock volume which can release seismic energy due to weakening effect of normal stress by injected fluid. Product of these two parameters (equation (1)) provide possible seismic moment which can be released from current stimulated zone as a model output. Difference between output of this model and observed cumulative seismic moment corresponds the seismic moment which will be released in future, based on current stimulation conditions. This value can be translated into possible maximum magnitude of induced seismicity in future. As this way, possible seismic moment can be used to have feedback to hydraulic stimulation operation in real time as an index which can be interpreted easily and intuitively. Possible seismic moment is defined as equation (1), where D

  19. Environmental assessment of proposed geothermal well testing in the Tigre Lagoon Oil Field, Vermilion Parish, Louisiana

    Energy Technology Data Exchange (ETDEWEB)


    An environmental assessment is made of the proposed testing of two geopressured, geothermal aquifers in central coastal Louisiana. On the basis of an analysis of the environmental setting, subsurface characteristics, and the proposed action, potential environmental impacts are determined and evaluated together with potential conflicts with federal, state, and local programs. (LBS )

  20. Geochemical/hydrochemical evaluation of the geothermal potential of the Lamongan volcanic field (Eastern Java, Indonesia)

    NARCIS (Netherlands)

    Deon, F.; Förster, H.J.; Brehme, M.; Wiegand, B.; Scheytt, T.; Moeck, I.; Jaya, M.S.; Putriatni, D.J.


    Magmatic settings involving active volcanism are potential locations for economic geothermal systems due to the occurrence of high temperature and steam pressures. Indonesia, located along active plate margins, hosts more than 100 volcanoes and, therefore, belongs to the regions with the greatest

  1. Sixteenth workshop on geothermal reservoir engineering: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, H.J. Jr.; Kruger, P.; Miller, F.G.; Horne, R.N.; Brigham, W.E.; Cook, J.W. (Stanford Geothermal Program)


    The Sixteenth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 23-25, 1991. The Workshop Banquet Speaker was Dr. Mohinder Gulati of UNOCAL Geothermal. Dr. Gulati gave an inspiring talk on the impact of numerical simulation on development of geothermal energy both in The Geysers and the Philippines. Dr. Gulati was the first recipient of The Stanford Geothermal Program Reservoir Engineering Award for Excellence in Development of Geothermal Energy. Dr. Frank Miller presented the award. The registered attendance figure of one hundred fifteen participants was up slightly from last year. There were seven foreign countries represented: Iceland, Italy, Philippines, Kenya, the United Kingdom, Mexico, and Japan. As last year, papers on about a dozen geothermal fields outside the United States were presented. There were thirty-six papers presented at the Workshop, and two papers were submitted for publication only. Attendees were welcomed by Dr. Khalid Aziz, Chairman of the Petroleum Engineering Department at Stanford. Opening remarks were presented by Dr. Roland Horne, followed by a discussion of the California Energy Commission's Geothermal Activities by Barbara Crowley, Vice Chairman; and J.E. ''Ted'' Mock's presentation of the DOE Geothermal Program: New Emphasis on Industrial Participation. Technical papers were organized in twelve sessions concerning: hot dry rock, geochemistry, tracer injection, field performance, modeling, and chemistry/gas. As in previous workshops, session chairpersons made major contributions to the program. Special thanks are due to Joel Renner, Jeff Tester, Jim Combs, Kathy Enedy, Elwood Baldwin, Sabodh Garg, Marcel0 Lippman, John Counsil, and Eduardo Iglesias. The Workshop was organized by the Stanford Geothermal Program faculty, staff, and graduate students. We wish to thank Pat Ota, Angharad Jones, Rosalee Benelli, Jeanne Mankinen, Ted Sumida, and Terri A. Ramey who also

  2. Health and safety impacts of nuclear, geothermal, and fossil-fuel electric generation in California. Volume 4. Radiological emergency response planning for nuclear power plants in California

    Energy Technology Data Exchange (ETDEWEB)

    Yen, W.W.S.


    This report reviews the state of emergency response planning for nuclear power plants in California. Attention is given to the role of Federal agencies, particularly the Nuclear Regulatory Commission, in planning for both on and off site emergency measures and to the role of State and local agencies for off site planning. The relationship between these various authorities is considered. Existing emergency plans for nuclear power plants operating or being constructed in California are summarized. The developing role of the California Energy Resources Conservation and Development Commission is examined.

  3. From oil field to geothermal reservoir: First assessment for geothermal utilization of two regionally extensive Devonian carbonate aquifers in Alberta, Canada


    Weydt, Leandra M.; Heldmann, Claus-Dieter J.; Machel, Hans G.; Sass, Ingo


    The Canadian Province of Alberta has the highest per capita CO2-equivalent emission of any jurisdiction in the world, predominantly due to industrial burning of coal for the generation of electricity and the mining operations in the oil sands deposits. Alberta’s geothermal potential could reduce CO2-emission by substituting at least some fossil fuels with geothermal energy. The Upper Devonian carbonate aquifer systems within the Alberta Basin are promising target formations for geothe...

  4. High-Resolution Analysis of Seismicity Induced at Berlín Geothermal Field, El Salvador (United States)

    Kwiatek, G.; Bulut, F.; Dresen, G. H.; Bohnhoff, M.


    We investigate induced microseismic activity monitored at Berlín Geothermal Field, El Salvador, during a hydraulic stimulation. The site was monitored for a time period of 17 months using thirteen 3-component seismic stations located in shallow boreholes. Three stimulations were performed in the well TR8A with a maximum injection rate and well head pressure of 160l/s and 130bar, respectively. For the entire time period of our analysis, the acquisition system recorded 581 events with moment magnitudes ranging between -0.5 and 3.7. The initial seismic catalog provided by the operator was substantially improved: 1) We re-picked P- and S-wave onsets and relocated the seismic events using the double-difference relocation algorithm based on cross-correlation derived differential arrival time data. Forward modeling was performed using a local 1D velocity model instead of homogeneous full-space. 2) We recalculated source parameters using the spectral fitting method and refined the results applying the spectral ratio method. We investigated the source parameters and spatial and temporal changes of the seismic activity based on the refined dataset and studied the correlation between seismic activity and production. The achieved hypocentral precision allowed resolving the spatiotemporal changes in seismic activity down to a scale of a few meters. The application of spectral ratio method significantly improved the quality of source parameters in a high-attenuating and complex geological environment. Of special interest is the largest event (Mw3.7) and its nucleation process. We investigate whether the refined seismic data display any signatures that the largest event is triggered by the shut-in of the well. We found seismic activity displaying clear spatial and temporal patterns that could be easily related to the amount of water injected into the well TR8A and other reinjection wells in the investigated area. The migration of seismicity outside of injection point is observed

  5. Geodetic Study of Ground Instability at Active Geothermal Reservoirs (United States)

    Aly, M. H.; Bawner, E.; Nanis, H.; Alotaibi, M.; Suwihli, S.


    Active geothermal systems may cause substantial crustal deformation that can damage the precious infrastructure and increase the frequency and magnitude of earthquakes in the surrounding region. Geothermal production practices commonly contribute to surface motions triggered by natural tectonic and volcanic forces at active geothermal fields and may intensify their significance over years. Hence, routine monitoring of active geothermal sites is required to evaluate the impact of production activities and assess associated ground instabilities. Knowledge of the reservoir geometry, compaction, and response to production behaviors will aid in identifying ideal locations for new production and recharge wells to advance the performance of such a reservoir. This study investigates active geothermal processes and recent seismic events and their impacts on crustal deformation at the Raft River Geothermal Power Plant (RGP) in southeastern Idaho and at the Coso Geothermal (CG) field in eastern California. Contemporary geodetic observations from Synthetic Aperture Radar Interferometry (InSAR) and Global Positioning System (GPS) imply a rapid rate of ground subsidence ( 7 cm/yr) across the Raft River Valley with a local anomaly of ample uplift (3 cm/yr) near RGP. The measured rate of deflation at CG is 3.1 cm/yr throughout a large area ( 55 sq km) that is directly correlating with the extent of active geothermal production. These rapid rates of ground deformation indicate considerable depressurization of the two reservoirs. Volumetric analysis and modeling are currently underway to characterize the two reservoirs and to infer their deformation source parameters. Understanding the hydrothermal-geomechanical response of the reservoirs to fluid production and injection is crucial for their management and development.

  6. Reservoir Considerations and Direct Uses of São Pedro do Sul Hydromineral and Geothermal Field, Northern Portugal (United States)

    Ferreira Gomes, L. M.; Neves Trota, A. P.; Sousa Oliveira, A.; Soares Almeida, S. M.


    São Pedro do Sul Hydromineral and Geothermal Field, located in the northern interior zone of Portugal (Lafões zone), has the greatest widespread utilization of geothermal energy in Portugal mainland and is the most important thermal centre from the economical revenues point of view, obtained from direct and indirect utilization of the thermal water, mostly for wellness, health, and leisure of human beings. Recent utilization includes district and greenhouses heating and even cosmetic applications. The Hydromineral Field includes two exploitable zones: the Termas and Vau Poles. The waters are recognised for their mineral and medicinal effects, since the time of the Romans about 2000 years ago and, later on, on the 12th century, by the first King of Portugal, D. Afonso Henriques. The traditional spring and the 500 m well (AC1), located in the Termas Pole, currently supplies artesian hot water flow of about 16.9 L/s with a temperature of 67 °C. Despite the low flow rate of the actual two exploration wells drilled in the Vau Pole, the geothermal potential is high; a new deep well is planned to be drilled in this zone where is expected to obtain fluid temperature of around 75 °C. The occurrence of São Pedro do Sul mineral water, included in the sulphurous type waters, are linked to Hercynian granitoids, emplaced between 290 and 321 Myr. There is a close relationship between the placement of the main hot springs and the Verin-Chaves-Penacova fault, namely Verin (Spain), Chaves, Moledo, and S. Pedro do Sul (Portugal) hot springs. Heat flow generated at shallow crustal zones by the radiogenic host mineral of the granitic rocks, added to the deep Earth heat flow, heats the cold water inflow along fractures. Open fracture network along the main faults allows the hot fluids reach the surface, thus giving chance to the occurrence of hot springs and mineralized cold springs. Coupling between fracture opening and density difference between cold water inflow and hot water

  7. Inversion modeling of the natural state and production history of Mutnovsky geothermal field in 1986-2006

    Directory of Open Access Journals (Sweden)

    А. В. Кирюхин


    Full Text Available Numerical 3D model of Mutnovsky geothermal field (Dachny springs, which consist of 517 elements and partially takes into account double porosity, was developed in 1992-1993 using computer program TOUGH2. Calibration of the model was based on data from test yield of the wells and initial distribution of temperature and pressure in the reservoir. This model was used for techno-economic justification of power plant construction (Mutnovskaya GeoES, 2002. The model was recreated in the program PetraSim v.5.2, the calibration was carried out using additional data on production history before year 2006 and inversion iTOUGH2-EOS1 modeling. Comparison of reservoir parameters, estimated using inversion modeling, with previous parameter estimations (given in brackets showed the following: upflow rate of heat-transfer agent in natural conditions 80.5 (54.1 kg/s, heat flux enthalpy 1430 (1390 kJ/kg, reservoir permeability 27∙10–15-616∙10–15 (3∙10–15-90∙10–15 m2. Inversion modeling was also used to estimate reinjection rates, inflow of meteoric water in the central part of geothermal field and compressibility of reservoir rocks.

  8. Inversion of Synthetic Aperture Radar Interferograms for Sources of Production-Related Subsidence at the Dixie Valley Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Foxall, W; Vasco, D


    We used synthetic aperture radar interferograms to image ground subsidence that occurred over the Dixie Valley geothermal field during different time intervals between 1992 and 1997. Linear elastic inversion of the subsidence that occurred between April, 1996 and March, 1997 revealed that the dominant sources of deformation during this time period were large changes in fluid volumes at shallow depths within the valley fill above the reservoir. The distributions of subsidence and subsurface volume change support a model in which reduction in pressure and volume of hot water discharging into the valley fill from localized upflow along the Stillwater range frontal fault is caused by drawdown within the upflow zone resulting from geothermal production. Our results also suggest that an additional source of fluid volume reduction in the shallow valley fill might be similar drawdown within piedmont fault zones. Shallow groundwater flow in the vicinity of the field appears to be controlled on the NW by a mapped fault and to the SW by a lineament of as yet unknown origin.

  9. Environmental protection at the Los Azufres, Michoacan geothermal field; La proteccion ambiental en el campo geotermico de Los Azufres, Michoacan

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza Rangel, Ernesto; Hernandez Ayala, Cuauhtemoc [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)


    Geothermal-electric development is a sustainable activity from an environmental viewpoint, as is proved by the operation and management of the Los Azufres geothermal field. Impacts to soil and vegetation can be prevented and adequately mitigated. Liquid residues can be returned to the reservoir avoiding contaminating surface and ground waters and aquifers; and atmospheric emissions can kept bellow allowable limits. The main environmental technical experiences of Comision Federal de Electricidad (CFE) in this field are presented in this paper. [Spanish] El desarrollo geotermoelectrico es una actividad sustentable desde el punto de vista ambiental, como lo prueba el manejo del campo geotermico de Los Azufres. Los impactos al suelo y a la vegetacion pueden prevenirse y mitigarse con las medidas adecuadas. Los desechos liquidos pueden regresarse al yacimiento sin contaminar cuerpos de agua superficiales o acuiferos someros, y las emisiones a la atmosfera pueden controlarse para mantenerlas dentro de limites permisibles. Se presentan las principales experiencias tecnicas de tipo ambiental obtenidas por la Comision Federal de Electricidad (CFE) en ese campo.

  10. Relation of compositions of deep fluids in geothermal activity of Pleistocene-Holocene volcanic fields of Lesser Caucasus (United States)

    Meliksetian, Khachatur; Lavrushin, Vassily; Shahinyan, Hrach; Aidarkozhina, Altin; Navasardyan, Gevorg; Ermakov, Alexander; Zakaryan, Shushan; Prasolov, Edward; Manucharyan, Davit; Gyulnazaryan, Shushan; Grigoryan, Edmond


    It is widely accepted, that geothermal activity in the conductive heat flow processes, such as volcanism and hydrothermal activity, is manifestation of the thermal mass transfer process in the Earth's crust, where geothermal and geochemical processes are closely connected. Therefore, geochemistry and isotope compositions of thermal mineral waters within and on periphery of volcanic clusters may represent key indicators for better understanding of geothermal activity in geodynamically active zones. Geochemical features of heat and mass transport in hydrothermal systems related to active volcanic and fault systems in continental collision related orogenic elevated plateaus such as Anatolian-Armenian-Iranian highlands are still poorly understood. In this contribution we attempt to fill these gaps in our knowledge of relations of geochemical and geothermal processes in collision zones. We present new data on chemical compositions, trace element geochemistry of thermal waters of Lesser Caucasus, (Armenia) as well as isotope analysis of free gases such as {}3He/{}4He, {}40Ar/{}36Ar, δ{}13?(CO{}2), nitrogen δ{}15N(N{}2) and oxygen and hydrogen isotopes in water phases (δD, δ{}18O). To reveal some specific features of formation of fluid systems related to thermal activity in the areas of collision related active volcanism and active geodynamics a complex geochemical (SiO{}2, K-Na, Na-Li, Li-Mg) and isotope geothermometers (δ{}18O(CaCO{}3) - δ{}18O(H{}2O)) were applied. The distribution of δ{}13?(??{}2) values in free gases of mineral waters of Armenia demonstrates that gases related to Quaternary volcanic fields are characterized by relatively light δ{}13?(CO{}2) values close to mantle derived gases, while on periphery of volcanic systems relatively heavy values of δ{}13?(CO{}2) indicate strong influence of metamorphic and sedimentary derived carbon dioxide. Distribution of nitrogen isotopes δ{}15N(N{}2) demonstrate an inverse correlation with δ{}13?(CO{}2

  11. Preliminary study of near surface detections at geothermal field using optic and SAR imageries (United States)

    Kurniawahidayati, Beta; Agoes Nugroho, Indra; Syahputra Mulyana, Reza; Saepuloh, Asep


    Current remote sensing technologies shows that surface manifestation of geothermal system could be detected with optical and SAR remote sensing, but to assess target beneath near the surface layer with the surficial method needs a further study. This study conducts a preliminary result using Optic and SAR remote sensing imagery to detect near surface geothermal manifestation at and around Mt. Papandayan, West Java, Indonesia. The data used in this study were Landsat-8 OLI/TIRS for delineating geothermal manifestation prospect area and an Advanced Land Observing Satellite(ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) level 1.1 for extracting lineaments and their density. An assumption was raised that the lineaments correlated with near surface structures due to long L-band wavelength about 23.6 cm. Near surface manifestation prospect area are delineated using visual comparison between Landsat 8 RGB True Colour Composite band 4,3,2 (TCC), False Colour Composite band 5,6,7 (FCC), and lineament density map of ALOS PALSAR. Visual properties of ground object were distinguished from interaction of the electromagnetic radiation and object whether it reflect, scatter, absorb, or and emit electromagnetic radiation based on characteristic of their molecular composition and their macroscopic scale and geometry. TCC and FCC composite bands produced 6 and 7 surface manifestation zones according to its visual classification, respectively. Classified images were then compared to a Normalized Different Vegetation Index (NDVI) to obtain the influence of vegetation at the ground surface to the image. Geothermal area were classified based on vegetation index from NDVI. TCC image is more sensitive to the vegetation than FCC image. The later composite produced a better result for identifying visually geothermal manifestation showed by detail-detected zones. According to lineament density analysis high density area located on the peak of Papandayan overlaid with zone 1

  12. Proceedings: third symposium on the Cerro Prieto geothermal field, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)


    These proceedings include both English and Spanish versions of each paper presented at the symposium. Illustrations and tables, which have been placed between the two versions, include captions in both languages. Forty-one papers are included. Five papers were indexed for EDB previously. Separate abstracts were prepared for thirty-three papers and three were listed by title.

  13. Advanced Geothermal Turbodrill

    Energy Technology Data Exchange (ETDEWEB)

    W. C. Maurer


    Approximately 50% of the cost of a new geothermal power plant is in the wells that must be drilled. Compared to the majority of oil and gas wells, geothermal wells are more difficult and costly to drill for several reasons. First, most U.S. geothermal resources consist of hot, hard crystalline rock formations which drill much slower than the relatively soft sedimentary formations associated with most oil and gas production. Second, high downhole temperatures can greatly shorten equipment life or preclude the use of some technologies altogether. Third, producing viable levels of electricity from geothermal fields requires the use of large diameter bores and a high degree of fluid communication, both of which increase drilling and completion costs. Optimizing fluid communication often requires creation of a directional well to intersect the best and largest number of fracture capable of producing hot geothermal fluids. Moineau motor stators made with elastomers cannot operate at geothermal temperatures, so they are limited to the upper portion of the hole. To overcome these limitations, Maurer Engineering Inc. (MEI) has developed a turbodrill that does not use elastomers and therefore can operate at geothermal temperatures. This new turbodrill uses a special gear assembly to reduce the output speed, thus allowing a larger range of bit types, especially tri-cone roller bits, which are the bits of choice for drilling hard crystalline formations. The Advanced Geothermal Turbodrill (AGT) represents a significant improvement for drilling geothermal wells and has the potential to significantly reduce drilling costs while increasing production, thereby making geothermal energy less expensive and better able to compete with fossil fuels. The final field test of the AGT will prepare the tool for successful commercialization.

  14. Stress field models from Maxwell stress functions: southern California (United States)

    Bird, Peter


    shallow stress maxima and discontinuous horizontal compression at the Moho, which the new model can only approximate. The new model also lacks the spatial resolution to portray the localized stress states that may occur near the central surfaces of weak faults; instead, the model portrays the regional or background stress field which provides boundary conditions for weak faults. Peak shear stresses in one registered model and one alternate model are 120 and 150 MPa, respectively, while peak vertically integrated shear stresses are 2.9 × 1012 and 4.1 × 1012 N m-1. Channeling of deviatoric stress along the strong Great Valley and the western slope of the Peninsular Ranges is evident. In the neotectonics of southern California, it appears that deviatoric stress and long-term strain rate have a negative correlation, because regions of low heat flow are strong and act as stress guides, while undergoing very little internal deformation. In contrast, active faults lie preferentially in areas with higher heat flow, and their low strength keeps deviatoric stresses locally modest.

  15. Differentiating induced and natural seismicity using space-time-magnitude statistics applied to the Coso Geothermal field (United States)

    Schoenball, Martin; Davatzes, Nicholas C.; Glen, Jonathan M. G.


    A remarkable characteristic of earthquakes is their clustering in time and space, displaying their self-similarity. It remains to be tested if natural and induced earthquakes share the same behavior. We study natural and induced earthquakes comparatively in the same tectonic setting at the Coso Geothermal Field. Covering the preproduction and coproduction periods from 1981 to 2013, we analyze interevent times, spatial dimension, and frequency-size distributions for natural and induced earthquakes. Individually, these distributions are statistically indistinguishable. Determining the distribution of nearest neighbor distances in a combined space-time-magnitude metric, lets us identify clear differences between both kinds of seismicity. Compared to natural earthquakes, induced earthquakes feature a larger population of background seismicity and nearest neighbors at large magnitude rescaled times and small magnitude rescaled distances. Local stress perturbations induced by field operations appear to be strong enough to drive local faults through several seismic cycles and reactivate them after time periods on the order of a year.

  16. Numerical modeling of the initial state and matching of well test data from the Zunil geothermal field, Guatemala

    Energy Technology Data Exchange (ETDEWEB)

    Menzies, A.J.; Granados, E.E.; Sanyal, .K.; Merida-I., L.; Caicedo-A, A.


    A significant amount of geoscientific and reservoir engineering data have been collected from the Zunil geothermal field since 1973. The data have been used to define a conceptual model for the field which has formed the basis for the construction of a three dimensional numerical simulation model. The numerical model has successfully matched both the initial state of the reservoir, as indicated by subsurface temperature and pressure distributions within the presently drilled area, and available well test data. The well test data include short and long term discharge tests and a comprehensive pressure interference test. Calibration of the model will continue during 1991 when the results from drilling and testing of three additional deep wells are available. The model will then be used to study various long term production scenarios for the proposed 15 MW power development.

  17. Reactive geothermal transport simulation to study the formation mechanism of impermeable barrier between acidic and neutral fluid zones in the Onikobe Geothermal Field, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Todaka, Norifumi; Akasaka, Chitosi; Xu, Tianfu; Pruess, Karsten


    Two types of fluids are encountered in the Onikobe geothermal reservoir, one is neutral and the other is acidic (pH=3). It is hypothesized that acidic fluid might be upwelling along a fault zone and that an impermeable barrier might be present between the acidic and neutral fluid zones. We carried out reactive geothermal transport simulations using TOUGHREACT (Xu and Pruess, 1998 and 2001) to test such a conceptual model. Mn-rich smectite precipitated near the mixing front and is likely to form an impermeable barrier between regions with acidic and neutral fluids.

  18. Time-series analysis of surface deformation at Brady Hot Springs geothermal field (Nevada) using interferometric synthetic aperture radar

    Energy Technology Data Exchange (ETDEWEB)

    Ali, S. T. [Univ. of Wisconsin, Madison, WI (United States); Akerley, J. [Ormat Technologies Inc., Reno, NV (United States); Baluyut, E. C. [Univ. of Wisconsin, Madison, WI (United States); Cardiff, M. [Univ. of Wisconsin, Madison, WI (United States); Davatzes, N. C. [Temple Univ., Philadelphia, PA (United States). Dept. of Earth and Environmental Science; Feigl, K. L. [Univ. of Wisconsin, Madison, WI (United States); Foxall, W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fratta, D. [Univ. of Wisconsin, Madison, WI (United States); Mellors, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Spielman, P. [Ormat Technologies Inc., Reno, NV (United States); Wang, H. F. [Univ. of Wisconsin, Madison, WI (United States); Zemach, E. [Ormat Technologies Inc., Reno, NV (United States)


    We analyze interferometric synthetic aperture radar (InSAR) data acquired between 2004 and 2014, by the ERS-2, Envisat, ALOS and TerraSAR-X/TanDEM-X satellite missions to measure and characterize time-dependent deformation at the Brady Hot Springs geothermal field in western Nevada due to extraction of fluids. The long axis of the ~4 km by ~1.5 km elliptical subsiding area coincides with the strike of the dominant normal fault system at Brady. Within this bowl of subsidence, the interference pattern shows several smaller features with length scales of the order of ~1 km. This signature occurs consistently in all of the well-correlated interferometric pairs spanning several months. Results from inverse modeling suggest that the deformation is a result of volumetric contraction in shallow units, no deeper than 600 m, likely associated with damaged regions where fault segments mechanically interact. Such damaged zones are expected to extend downward along steeply dipping fault planes, providing a high permeability conduit to the production wells. Using time series analysis, we test the hypothesis that geothermal production drives the observed deformation. We find a good correlation between the observed deformation rate and the rate of production in the shallow wells. We also explore mechanisms that could potentially cause the observed deformation, including thermal contraction of rock, decline in pore pressure and dissolution of minerals over time.

  19. Direct utilization of geothermal resources field experiments at Monroe, Utah. Final report, July 14, 1978-July 13, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Blair, C.K.; Owen, L.B. (eds.)


    The City of Monroe, Utah undertook a project to demonstrate the economic and technical viability of utilizing a low temperature geothermal resource to provide space and hot water heating to commercial, municipal, and domestic users within the community. During the course of the project, resource development and assessment, including drilling of a production well, was successfully completed. Upon completion of the field development and assessment phase of the program and of a preliminary design of the district heating system, it was determined that the project as proposed was not economically viable. This was due to: (1) a significant increase in estimated capital equipment costs resulting from the general inflation in construction costs, the large area/low population density in Monroe, and a more remote fluid disposal well site than planned, could not balance increased construction costs, (2) a lower temperature resource than predicted, and (3) due to predicted higher pumping and operating costs. After a thorough investigation of alternatives for utilizing the resource, further project activities were cancelled because the project was no longer economical and an alternative application for the resource could not be found within the constraints of the project. The City of Monroe, Utah is still seeking a beneficial use for the 600 gpm, 164/sup 0/F geothermal well. A summary of project activities included.

  20. Spatial distribution of temperature in the low-temperature geothermal Euganean field (NE Italy): a simulated annealing approach

    Energy Technology Data Exchange (ETDEWEB)

    Fabbri, Paolo; Trevisani, Sebastiano [Dipartimento di Geologia, Paleontologia e Geofisica, Universita degli Studi di Padova, via Giotto 1, 35127 Padova (Italy)


    The spatial distribution of groundwater temperatures in the low-temperature (60-86{sup o}C) geothermal Euganean field of northeastern Italy has been studied using a geostatistical approach. The data set consists of 186 temperatures measured in a fractured limestone reservoir, over an area of 8km{sup 2}. Investigation of the spatial continuity by means of variographic analysis revealed the presence of anisotropies that are apparently related to the particular geologic structure of the area. After inference of variogram models, a simulated annealing procedure was used to perform conditional simulations of temperature in the domain being studied. These simulations honor the data values and reproduce the spatial continuity inferred from the data. Post-processing of the simulations permits an assessment of temperature uncertainties. Maps of estimated temperatures, interquartile range, and of the probability of exceeding a prescribed 80{sup o}C threshold were also computed. The methodology described could prove useful when siting new wells in a geothermal area. (author)

  1. Regional systems development for geothermal energy resources: Pacific region (California and Hawaii). Task I: implementation plan development, topical report

    Energy Technology Data Exchange (ETDEWEB)

    Michler, D.W.


    Eleven implementation plans were prepared. They represent some 21 reservoir-site developments and 48 geothermal power plant developments. The plans consist of three integrated elements: (1) a bar-chart schedule that depicts interdependencies among activities and shows significant milestones on the path from initial exploration to power on-line, (2) task descriptions, and (3) the responsible performers. During the preparation of the implementation plans, the tasks required for resource development at each KGRA were defined on a generalized work breakdown structure (WBS) diagram. A generalized WBS dictionary (task descriptions) was also compiled. In addition, a specific WBS for each KGRA was prepared in a tabular and indented format. The tasks formed the basis for the schedular activities. Institutional responsibilities, based upon the WBS, were identified and are also shown on the tabular WBS. In this manner, implementation plans evolved whose schedular, task, and responsibility elements were integrated with one another. In order to provide logically consistent time estimates, and a reasonable basis for comparison, schedule modules were developed for some recurring activities which are essentially common to all KGRAs. In the preparation of multiple plant schedules for a given KGRA, the interactive effects of power development on the ancillary resources of the area were considered so that interfaces and constraining situations would be identified. Within Imperial County, this process was taken one step further to include the influence that development at the several close-lying KGRAs would have upon one another. A set of recommendations for the accelerated development of geothermal energy resources was prepared and the potential implementors were suggested.

  2. Comparison of the earth's crust geothermal field in Northern Tien Shan region with seismic characteristics

    Directory of Open Access Journals (Sweden)

    Vilayev Andrey


    Full Text Available The deep crustal temperatures of the Northern Tien Shan region are being calculated on the basis of direct measurements of the heat flow and empirical relation of geothermal parameters and seismic velocities. For this purpose the applied method of numerical solution of conductive heat transfer equation takes into account additional sources of heat release due to radioactive decay. Thermoelastic deformations, reaching 20-40% of the total lithostatic pressure at depths of 35-60 km, are determined. The criteria controlling the distribution of hypocenters of earthquakes have been determined in accordance with the morphology of the regions of excess temperatures and thermal stresses.

  3. Comparison of the earth's crust geothermal field in Northern Tien Shan region with seismic characteristics (United States)

    Vilayev, Andrey; Zhantaev, Zhumabek


    The deep crustal temperatures of the Northern Tien Shan region are being calculated on the basis of direct measurements of the heat flow and empirical relation of geothermal parameters and seismic velocities. For this purpose the applied method of numerical solution of conductive heat transfer equation takes into account additional sources of heat release due to radioactive decay. Thermoelastic deformations, reaching 20-40% of the total lithostatic pressure at depths of 35-60 km, are determined. The criteria controlling the distribution of hypocenters of earthquakes have been determined in accordance with the morphology of the regions of excess temperatures and thermal stresses.

  4. Results of an injection test using ethyl alcohol as tracer at Los Humeros geothermal field, Puebla, Mexico; Resultados de una prueba de inyeccion de alcohol empleado como trazador, en el campo geotermico de Los humeros, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Tovar Aguado, Rigoberto; Lopez Romero, Oscar [Comision Federal de Electricidad, Los Humeros, Puebla (Mexico)


    Los Humeros is the third Mexican geothermal field where ethyl alcohol was used as organic tracer to test communication between wells. The first Mexican geothermal field where this kind of test was used Los Azufres, Michoacan. The second was Las Tres Virgenes, Baja California Sur. In both cases, connections between wells were observed. The injection well H-29 is in the north-central sector of Los Humeros geothermal field, Puebla, Mexico. At a depth of 1580 meters, 600 liters of ethyl alcohol was pumped through a 60.35 mm (23/8 inch) diameter tube after 2.7 m{sup 3} of geothermal fluids were displaced, allowing the alcohol to reach the formation. Then, the normal injection process continued with water and condensed steam (130 t/h). On the basis of the experience acquired with similar tests conducted at Las Tres Virgenes geothermal field, and with the goal of detecting the tracer, samples of condensed steam were collected in nearby wells (H-15, H-16, H-17, H-30, H-33, H-36 and H-8) and in distant wells-named special samples (H-32, H-1, H-11, H-12, H-19, H-20, H-35, H-37, H-39, H-6 and H-9). Condensed steam samples were collected every 12 hours, the every week and finally every 15 days, making a total of 592 samples. The chemical analysis were done in two stages because of probable with the chromatograph. In the first stage, 441 samples were run and the rest were run in the second stage. No evidence of the tracer was observed in the monitoring wells. The results confirm the existence of a low-to-moderate permeability, as was previously interpreted using pressure log data. [Spanish] Los Humeros es el tercer campo geotermico de Mexico en el que se realiza una prueba de trazadores organicos empleando alcohol etilico con la finalidad principal de conocer si existe comunicacion entre pozos. El primer campo geotermico en el que se realizo esta prueba fue el de Los Azufres, Michoacan y el segundo el de Las Tres Virgenes, Baja California Sur; en ambos casos se encontro

  5. Imperial County geothermal development. Quarterly report, April 1-June 30, 1982

    Energy Technology Data Exchange (ETDEWEB)


    The activities of the Geothermal Office during the quarter are discussed, including: important geothermal events, geothermal waste disposal, a grant award by the California Energy Commission, the geothermal development meeting, and the current status of geothermal development in Imperial County. Activities of the Geothermal Planner are addressed, including permits, processing of EIR's, and other planning activities. Progress on the direct heat study is reported.

  6. Geothermal Energy

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  7. Geology of the Pavana geothermal area, Departamento de Choluteca, Honduras, Central America: Field report

    Energy Technology Data Exchange (ETDEWEB)

    Eppler, D.B.; Heiken, G.; Wohletz, K.; Flores, W.; Paredes, J.R.; Duffield, W.A.


    The Pavana geothermal area is located in southern Honduras near the Gulf of Fonseca. This region is underlain by late Tertiary volcanic rocks. Within ranges near the geothermal manifestations, the rock sequences is characterized by intermediate to mafic laharic breccias and lavas overlain by silicic tuffs and lavas, which are in turn overlain by intermediate to mafic breccias, lavas, and tuffs. The nearest Quaternary volcanoes are about 40 km to the southwest, where the chain of active Central American volcanoes crosses the mouth of the Gulf of Fonseca. Structure of the Pavana area is dominated by generally northwest-trending, southwest-dipping normal faults. This structure is topographically expressed as northwest-trending escarpments that bound blocks of bedrock separated by asymmetric valleys that contain thin alluvial deposits. Thermal waters apparently issue from normal faults and are interpreted as having been heated during deep circulation along fault zones within a regional environment of elevated heat flow. Natural outflow from the main thermal area is about 3000 l/min of 60/sup 0/C water. Geothermometry of the thermal waters suggests a reservoir base temperature of about 150/sup 0/C.

  8. Idaho Geothermal Commercialization Program. Idaho geothermal handbook

    Energy Technology Data Exchange (ETDEWEB)

    Hammer, G.D.; Esposito, L.; Montgomery, M.


    The following topics are covered: geothermal resources in Idaho, market assessment, community needs assessment, geothermal leasing procedures for private lands, Idaho state geothermal leasing procedures - state lands, federal geothermal leasing procedures - federal lands, environmental and regulatory processes, local government regulations, geothermal exploration, geothermal drilling, government funding, private funding, state and federal government assistance programs, and geothermal legislation. (MHR)

  9. Reconnaissance Study of Coso Volcanic Field, California, and Pickel Meadow, California (United States)


    arsenic (As), gold (Au), cadmium (Cd), antimony (Sb), and zinc (Zn) in stream sediments, for Au, Cd, and Zn in heavy-mineral concentrates, and for...were collected along California State I lighway 108 between Sardine and Leavitt Meadow. The Pickel Meadow samples were collected in a square grid

  10. Geothermal reservoir technology

    Energy Technology Data Exchange (ETDEWEB)

    Lippmann, M.J.


    A status report on Lawrence Berkeley Laboratory's Reservoir Technology projects under DOE's Hydrothermal Research Subprogram is presented. During FY 1985 significant accomplishments were made in developing and evaluating methods for (1) describing geothermal systems and processes; (2) predicting reservoir changes; (3) mapping faults and fractures; and (4) field data analysis. In addition, LBL assisted DOE in establishing the research needs of the geothermal industry in the area of Reservoir Technology. 15 refs., 5 figs.

  11. Dynamics of a geothermal field traced by noble gases: Cerro Prieto, Mexico (United States)

    Mazor, E.; Truesdell, A.H.


    Noble gases have been measured mass spectrometrically in samples collected during 1977 from producing wells at Cerro Prieto. Positive correlations between concentrations of radiogenic (He and 40Ar) and atmospheric noble gases (Ne, Ar and Kr) suggest the following dynamic model: the geothermal fluids originated from meteoric water that penetrated to more than 2500 m depth (below the level of first boiling) and mixed with radiogenic He and 40Ar formed in the aquifer rocks. Subsequently, small amounts of steam were lost by a Raleigh process (0 - 30%) and mixing with shallow cold water occurred (0 - 30%). Noble gases are sensitive tracers of boiling in the initial stages of 0 - 3% steam separation and complement other tracers, such as C1 or temperature, which are effective only beyond this range. ?? 1984.

  12. Dynamics of a geothermal field traced by noble gases: Cerro Prieto, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Mazor, E. (Weizmann Inst. of Science, Rehovot, Israel); Truesdell, A.H.


    Noble gases have been measured mass spectrometrically in samples collected during 1977 from producing wells at Cerro Prieto. Positive correlations between concentrations of radiogenic (He, /sup 40/Ar) and atmospheric noble gases (Ne, Ar, and Kr) suggest the following dynamic model: the geothermal fluids originated from meteoric water penetrated to more than 2500 m depth (below the level of first boiling) and mixed with radiogenic helium and argon-40 formed in the aquifer rocks. Subsequently, small amounts of steam were lost by a Raleigh process (0 to 3%) and mixing with shallow cold water occurred (0 to 30%). Noble gases are sensitive tracers of boiling in the initial stages of 0 to 3% steam separation and complement other tracers, such as Cl or temperature, which are effective only beyond this range.

  13. The Tianjin geothermal field (north-eastern China): Water chemistry and possible reservoir permeability reduction phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Minissale, Angelo; Montegrossi, Giordano; Orlando, Andrea [Institute of Geosciences and Earth Resources, National Research Council of Italy (CNR), Via G. La Pira 4, 50121 Florence (Italy); Borrini, Daniele; Tassi, Franco [Department of Earth Sciences, University of Florence, Via G. La Pira 4, 50121 Florence (Italy); Vaselli, Orlando [Institute of Geosciences and Earth Resources, National Research Council of Italy (CNR), Via G. La Pira 4, 50121 Florence (Italy); Department of Earth Sciences, University of Florence, Via G. La Pira 4, 50121 Florence (Italy); Huertas, Antonio Delgado [Estacion Experimental de Zaidin (CSIC), Prof. Albareda 1, 18008 Granada (Spain); Yang, Jincheng; Cheng, Wanquing [Aode Renewable Energy Research Institute, 90 Weijin South Road, Nankai District, 300381 Tianjin (China); Tedesco, Dario [Department of Environmental Sciences, Second University of Naples, Via Vivaldi 43, Caserta 81100 (Italy); Institute of Environmental Geology and Geo Engineering (CNR), Piazzale A. Moro 5, Roma 00100 (Italy); Poreda, Robert [Department of Earth and Environmental Sciences, University of Rochester, 227 Hutchison Hall, Rochester, NY 14627 (United States)


    Injection of spent (cooled) thermal fluids began in the Tianjin geothermal district, north-eastern China, at the end of the 1990s. Well injectivities declined after 3-4 years because of self-sealing processes that reduced reservoir permeability. The study focuses on the factors that may have caused the observed decrease in permeability, using chemical and isotopic data on fluids (water and gas) and mineral phases collected from production and injection wells. The results of data processing and interpretation indicate that (1) it is very unlikely that calcite and silica precipitation is taking place in the reservoir; (2) the Fe- and Zn-rich mineral phases (e.g. sulfides, hydroxides and silicates) show positive saturation indexes; (3) SEM and XRD analyses of filtered material reveal that the latter mineral phases are common; (4) visual observation of casings and surface installations, and of corrosion products, suggests that a poor quality steel was used in their manufacture; (5) significant quantities of solids (e.g. quartz and feldspar crystals) are carried by the geothermal fluid; (6) seasonal changes in fluid composition lead to a reduction in casing corrosion during the summer. It was concluded that the decrease in injectivity in the Tianjin wells is caused only in part by the oxidation of casings, downhole pumps, and surface installations, triggered by free oxygen in the injected fluids; the utilization of better quality steels should drastically reduce this type of corrosion. Self-sealing of pores and fractures by reservoir formation solids and by the Fe-corrosion products suspended in the injected fluids seems to be a more important phenomenon, whose effect could be greatly reduced by installing filtering devices at all sites. (author)

  14. Subsidence due to geothermal fluid withdrawal

    Energy Technology Data Exchange (ETDEWEB)

    Narasimhan, T. N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division; Univ. of California, Berkeley, CA (United States); Goyal, K. P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division; Univ. of California, Berkeley, CA (United States)


    Single-phase and two-phase geothermal reservoirs are currently being exploited for power production in Italy, Mexico, New Zealand, the United States, and elsewhere. Vertical ground displacements of up to 4.5 m and horizontal ground displacements of up to 0.5 m have been observed at Wairakei, New Zealand, that are clearly attributable to the resource exploitation. Similarly, vertical displacements of about 0.13 m have been recorded at The Geysers, California. No significant ground displacements that are attributable to large-scale fluid production have been observed at Larderello, Italy, and Cerro Prieto, Mexico. In this paper, observations show that subsidence due to geothermal fluid production is characterized by such features as an offset of the subsidence bowl from the main area of production, time-lag between production and subsidence, and nonlinear stress-strain relationships. Several plausible conceptual models, of varying degrees of sophistication, have been proposed to explain the observed features. At present, relatively more is known about the physical mechanisms that govern subsidence than the relevant thermal mechanisms. Finally, although attempts have been made to simulate observed geothermal subsidence, the modeling efforts have been seriously limited by a lack of relevant field data needed to sufficiently characterize the complex field system.

  15. Hot and steamy fractures in the Philippines: the characterisation and permeability evaluation of fractures of the Southern Negros Geothermal Field, Negros Oriental, Philippines (United States)

    Pastoriza, Loraine; Holdsworth, Robert; McCaffrey, Kenneth; Dempsey, Eddie; Walker, Richard; Gluyas, Jon; Reyes, Jonathan


    Fluid flow pathway characterisation is critical to geothermal exploration and exploitation. It requires a good understanding of the structural evolution, fault distribution and fluid flow properties. A dominantly fieldwork-based approach has been used to evaluate the potential fracture permeability characteristics of a typical high-temperature geothermal reservoir in the Southern Negros Geothermal Field, Philippines. This is a liquid-dominated geothermal resource hosted in the andesitic to dacitic Quaternary Cuernos de Negros Volcano in Negros Island. Fieldwork reveals two main fracture groups based on fault rock characteristics, alteration type, relative age of deformation, and associated thermal manifestation, with the younger fractures mainly related to the development of the modern geothermal system. Palaeostress analyses of cross-cutting fault and fracture arrays reveal a progressive counterclockwise rotation of stress axes from the (?)Pliocene up to the present-day, which is consistent with the regional tectonic models. A combined slip and dilation tendency analysis of the mapped faults indicates that NW-SE structures should be particularly promising drilling targets. Frequency versus length and aperture plots of fractures across six to eight orders of magnitude show power-law relationships with a change in scaling exponent in the region of 100 to 500m length-scales. Finally, evaluation of the topology of the fracture branches shows the dominance of Y-nodes that are mostly doubly connected suggesting good connectivity and permeability within the fracture networks. The results obtained in this study illustrate the value of methods that can be globally applied during exploration to better characterize fracture systems in geothermal reservoirs using multiscale datasets.

  16. Physico-chemical and environmental controls on siliceous sinter formation at the high-altitude El Tatio geothermal field, Chile (United States)

    Nicolau, Constanza; Reich, Martin; Lynne, Bridget


    El Tatio geothermal field is located 4270 m above sea level in the Altiplano, northern Chile. Siliceous sinter deposits from El Tatio were studied to understand the influence of water chemistry and the extreme climatic conditions on their textures and mineralogy. The results of this study show that the mineralogy of El Tatio sinters include of opal-A and accessory minerals, such as halite, gypsum and cahnite (Ca4B2As2O12•4H2O), which precipitate by full evaporation of high arsenic, boron and calcium thermal waters. El Tatio sinters show a high degree of structural disorder, probably linked to cation incorporation into the silica structure and/or the occurrence of micro- to nano-scale accessory minerals. The high content of cations in the thermal waters is strongly tied to relatively high silica precipitation rates considering silica concentration in water (147-285 mg/l SiO2). Precipitation rate reach 2.5 kg/m2 per year based on in situ precipitation experiments. The particular environmental conditions of this high-altitude geothermal area that produce high water cooling rate and high evaporation rate, may also be responsible for the fast silica precipitation. Low environmental temperatures create freezing-related sinter textures (i.e., silica platelets and micro columns/ridges). Silicified microbial filaments are also characteristic of El Tatio sinters, and they are indicative of water temperature and hydrodynamic conditions at the moment of sinter formation. However, sinter textural interpretation in a high-altitude Andean context must be done carefully as specific relationships between microbial and hydrodynamic textures are found.

  17. Book review: Peeters, H. 2007. Field guide to owls of California and the West (United States)

    Eric D. Forsman


    Field Guide to Owls of California and the West. Written primarily for nonprofessionals,this little field guide is a treasure trove of published and unpublished information on the natural history and distribution of owls in the western United States. It covers just about everything you could want to know about owls, from why they take dust baths, to facultative...

  18. Geothermal well log interpretation state of the art. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sanyal, S.K.; Wells, L.E.; Bickham, R.E.


    An in-depth study of the state of the art in Geothermal Well Log Interpretation has been made encompassing case histories, technical papers, computerized literature searches, and actual processing of geothermal wells from New Mexico, Idaho, and California. A classification scheme of geothermal reservoir types was defined which distinguishes fluid phase and temperature, lithology, geologic province, pore geometry, salinity, and fluid chemistry. Major deficiencies of Geothermal Well Log Interpretation are defined and discussed with recommendations of possible solutions or research for solutions. The Geothermal Well Log Interpretation study and report has concentrated primarily on Western US reservoirs. Geopressured geothermal reservoirs are not considered.

  19. Resource investigation of low- and moderate-temperature geothermal areas in San Bernardino, California. Part of the third year report, 1980-81, of the US Department of Energy-California State-Coupled Program for Reservoir Assessment and Confirmation

    Energy Technology Data Exchange (ETDEWEB)

    Youngs, L.G.; Bezore, S.P.; Chapman, R.H.; Chase, G.W.


    Ninety-seven geothermal wells and springs were identified and plotted on a compiled geologic map of the 40-square-mile study area. These wells and springs were concentrated in three distinguishable resource areas: Arrowhead Hot Springs; South San Bernardino; and Harlem Hot Springs - in each of which detailed geophysical, geochemical, and geological surveys were conducted. The Arrowhead Hot Springs geothermal area lies just north of the City of San Bernardino in the San Bernardino Mountains astride a shear zone (offshoot of the San Andreas fault) in pre-Cambrian gneiss and schist. The Harlem Hot Springs geothermal area, on the east side of the City, and the south San Bernardino geothermal area, on the south side, have geothermal reservoirs in Quaternary alluvial material which overlies a moderately deep sedimentary basin bound on the southwest by the San Jacinto fault (a ground water barrier). Geothermometry calculations suggest that the Arrowhead Hot Springs geothermal area, with a maximum reservoir temperature of 142/sup 0/C, may have the highest maximum reservoir temperature of the three geothermal areas. The maximum temperature recorded by CDMG in the south San Bernardino geothermal area was 56/sup 0/C from an artesian well, while the maximum temperature recorded in the Harlem Hot Springs geothermal area was 49.5/sup 0/C at 174 meters (570 feet) in an abandoned water well. The geophysical and geological surveys delineated fault traces in association with all three of the designated geothermal areas.

  20. Investigations of the UK heat flow field (1984-1987). Investigation of the geothermal potential of the UK

    Energy Technology Data Exchange (ETDEWEB)

    Gebski, J.S.; Wheildon, J.; Thomas-Betts, J.


    Between 1984 and 1987, twenty-two new heat flow measurements have been added to the previously reported coverage of around 200 observations. These include observations in two deep boreholes drilled as part of the BGS geothermal exploration programme. Eleven of the sites were specially drilled heat flow boreholes between 100 m and 300 m deep. The remaining observations were made at locations where additional refinement of the heat flow field was warranted. Much of the effort in the present programme has been towards a better definition of the heat flow field associated with the high heat producing granites of the Lake District and Weardale, particularly where the granite extends in the subsurface to the edge of the Tyneside urban conurbation. The apparent high heat flow in the Bowland Forest can no longer be sustained, and the previously reported high heat flows are judged to be enhanced through convective circulation. Some refinements of the heat flow field in the Midland Valley of Scotland and in South Wales have resulted from new observations in these areas.

  1. Investigations of the UK heat flow field (1984-1987). Investigation of the geothermal potential of the UK

    Energy Technology Data Exchange (ETDEWEB)

    Gebski, J.S.; Wheildon, J.; Thomas-Betts, A.


    Between 1984 and 1987, twenty-two new heat flow measurements have been added to the previously reported coverage of around 200 observations. These include observations in two deep boreholes drilled as part of the BGS geothermal exploration programme. Eleven of the sites were specially drilled heat flow boreholes between 100 m and 300 m deep. The remaining observations were made in exploration boreholes at locations where additional refinement of the heat flow field was warranted. Much of the effort in the present programme has been towards a better definition of the heat flow field associated with the high heat producing granites of the Lake District and Weardale, particularly where the granite extends in the subsurface to the edge of the Tyneside urban conurbation. The apparent high heat flow in the Bowland Forest can no longer be sustained, and the previously reported high heat flows are judged to be enhanced through convective circulation. Some refinements of the heat flow field in the Midland Valley of Scotland and in South Wales have resulted from new observations in these areas. Elsewhere the new observations have been in substantial agreement with the results of earlier work. The results from two shallow boreholes to test basement heat flow were inconclusive in the complex geological settings selected.

  2. Coupled flow and geomechanics modeling of fracture reactivation and induced seismicity in the Basel geothermal field (United States)

    Tyukhova, A.; Castineira, D.; Juanes, R.


    Triggered and induced seismicity is at the cornerstone of discussions surrounding a wide range of subsurface technologies, e.g. unconventional hydrocarbon recovery, geologic carbon sequestration, underground gas storage, and geothermal energy extraction. We revisit the geothermal experiment in Basel, Switzerland, in which over 11 thousand cubic meters of water were injected into deep fractured crystalline rock. The injection took place in December 2006 and was performed at a single injection well, in three stages with increasing injection rate. Seismicity in the region increased during the experiment—with most of the seismic events occurring in the month following injection—and declined slowly after, but with seismic events still being recorded years after injection. The increase in seismicity is caused by reactivation of the pre-existing fractures: an increase in pore pressure decreases the normal effective stress across the fracture, which according to the Mohr-Coulomb failure criterion are therefore more prone to slip. The underlying processes, however, may be more complex. It is unclear the role that enhanced hydraulic connectivity in the fracture network plays on triggered seismicity, and on the emergence of seismicity clusters in space. It is also unclear what determines the delay between injection and recorded seismicity, and whether it can be explained by means of pressure propagation and/or dynamic weakening of fractures due to a drop in the friction coefficient as a result of decreased roughness from fracture slip. Here, we employ a computational model of coupled flow and geomechanics to quantitatively assess the impact of fluid injection on the recorded seismicity. We develop a simulation model that incorporates more than ten fractures, whose location, rake and dip are consistent with clusters of seismicity from a relocation of hypocenters and focal mechanisms. We adopt a multiscale description of flow (representing these fractures planes explicitly

  3. Geothermal Program Review XII: proceedings. Geothermal Energy and the President's Climate Change Action Plan

    Energy Technology Data Exchange (ETDEWEB)


    Geothermal Program Review XII, sponsored by the Geothermal Division of US Department of Energy, was held April 25--28, 1994, in San Francisco, California. This annual conference is designed to promote effective technology transfer by bringing together DOE-sponsored researchers; utility representatives; geothermal energy developers; suppliers of geothermal goods and services; representatives from federal, state, and local agencies; and others with an interest in geothermal energy. In-depth reviews of the latest technological advancements and research results are presented during the conference with emphasis on those topics considered to have the greatest potential to impact the near-term commercial development of geothermal energy.

  4. San Ignacio (La Tembladera) geothermal site, Departamento de Francisco Morazan, Honduras, Central America: Geological field report

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, M.J.; Eppler, D.; Heiken, G.; Flores, W.; Ramos, N.; Ritchie, A.


    The San Ignacio (La Tembladera) geothermal site is located on the north side of the Siria Valley, Departamento de Francisco Morazan, near the village of Barrosa. Hot springs are located along a northwest-trending fault scarp at the edge of the valley and along north-trending faults that cross the scarp. The rocks in the area are primarily Paleozoic metamorphic rocks, overlain by patches of Tertiary Padre Miguel Group tuffs and alluvial deposits. Movement probably occurred along several faults during latest Tertiary and possibly early Quaternary times. Four spring areas were mapped. Area 1, the largest, is associated with a sinter mound and consists of 40 spring groups. About half of the springs, aligned along a north-south trend, are boiling. Area 2 is a small sinter mound with several seeps. Area 3 consists of a group of hot and boiling springs aligned along a north-trending fault. The springs rise through fractured schists and a thin cover of alluvium. Area 4 is located at the intersection of several faults and includes one of the largest boiling springs in the area.

  5. Methods for collection and analysis of geopressured geothermal and oil field waters

    Energy Technology Data Exchange (ETDEWEB)

    Lico, M.S.; Kharaka, Y.K.; Carothers, W.W.; Wright, V.A.


    Present methods are described for the collection, preservation, and chemical analysis of waters produced from geopressured geothermal and petroleum wells. Detailed procedures for collection include precautions and equipment necessary to ensure that the sample is representative of the water produced. Procedures for sample preservation include filtration, acidification, dilution for silica, methyl isobutyl ketone (MIBK) extraction of aluminum, addition of potassium permanganate to preserve mercury, and precipitation of carbonate species as strontium carbonate for stable carbon isotopes and total dissolved carbonate analysis. Characteristics determined at the well site are sulfide, pH, ammonia, and conductivity. Laboratory procedures are given for the analysis of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, iron, manganese, zinc, lead, aluminum, and mercury by atomic absorption and flame emission spectroscopy. Chloride is determined by silver nitrate titration and fluoride by ion-specific electrode. Bromide and iodide concentrations are determined by the hypochlorite oxidation method. Sulfate is analyzed by titration using barium chloride with thorin indicator after pretreatment with alumina. Boron and silica are determined colorimetrically by the carmine and molybdate-blue methods, respectively. Aliphatic acid anions (C/sub 2/ through C/sub 5/) are determined by gas chromatography after separation and concentration in a chloroform-butanol mixture.

  6. Imperial County geothermal development annual meeting: summary

    Energy Technology Data Exchange (ETDEWEB)


    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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Gritto, Roland [Array Information Technology, Greenbelt, MD (United States); Dreger, Douglas [Univ. of California, Berkeley, CA (United States); Heidbach, Oliver [Helmholtz Centre Potsdam (Germany, German Research Center for Geosciences; Hutchings, Lawrence [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)


    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

  8. Long Range Effect of The M7.8 April 2015 Nepal Earth Quake on the Deep Groudwater Outflow in a Thousand-Mile-Away Geothermal Field in Southern China's Guangdong (United States)

    Lu, G.; Yu, S.; Xu, F.; Wang, X.; Yan, K.; Yuen, D. A.


    Deep ground waters sustain high temperature and pressure and are susceptible to impact from an earthquake. How an earthquake would have been associated with long-range effect on geological environment of deep groundwater is a question of interest to the scientific community and general public. The massive Richter 8.1 Nepal Earthquake (on April 25, 2015) provided a rare opportunity to test the response of deep groundwater systems. Deep ground waters at elevated temperature would naturally flow to ground surface along preferential flow path such as a deep fault, forming geothermal water flows. Geothermal water flows are susceptible to stress variation and can reflect the physical conditions of supercritical hot water kilometers deep down inside the crust. This paper introduces the monitoring work on the outflow in Xijiang Geothermal Field of Xinyi City, Guangdong Province in southern China. The geothermal field is one of typical geothermal fields with deep faults in Guangdong. The geothermal spring has characteristic daily variation of up to 72% in flow rate, which results from being associated with a north-south run deep fault susceptible to earthquake event. We use year-long monitoring data to illustrate how the Nepal earthquake would have affected the flows at the field site over 2.5 thousand kilometers away. The irregularity of flow is judged by deviation from otherwise good correlation of geothermal spring flow with solid earth tidal waves. This work could potentially provide the basis for further study of deep groundwater systems and insight to earthquake prediction.

  9. Microbial Diversity, Distribution and Insight into Their Role in S, Fe and N Biogeochemical Cycling in the Hot Springs at Tengchong Geothermal Fields, Southwest China (United States)

    Li, J.; Peng, X.; Zhang, L.


    Ten sediment samples collected from one acidic and three alkaline high temperature hot springs at Tengchong terrestrial geothermal field, Southwest China, were examined by the mineralogical, geochemical, and molecular biological techniques. The mineralogical and geochemical analyses suggested that these hot springs contain relative high concentrations of S, Fe and N chemical species. Specifically, the acidic hot spring was rich in Fe2+, SO42- and NH4+, while the alkaline hot springs were high in NO3-, H2S and S2O3-. Analyses of 16S rRNA sequences showed their bacterial communities were dominated by Aquificae, Cyanobacteria, Deinococci-Thermus, Firmicutes, Proteobacteria, and Thermodesulfobacteria, while the archeal clone libraries were dominated by Desulfurococcales, Sulfolobales, and Thermoproteales. Among them, the potential S-, N- and Fe-related oxidizing and reducing prokaryote were presenting as a relative high proportion but with a great difference in diversity and metabolic approaches of each sample. These findings provide some significant implications for the microbial function in element biogeochemical cycles within the Tengchong geothermal environments: i). the distinct differences in abundance and diversity of microbial communities of geothermal sediments were related to in situ different physicochemical conditions; ii). the S-, N- and Fe-related prokaryote would take advantage of the strong chemical disequilibria in the hot springs; iii). in return, their metabolic activities can promote the transformation of S, Fe and N chemical species, thus founded the bases of biogeochemical cycles in the terrestrial geothermal environments.

  10. Crosshole EM for oil field characterization and EOR monitoring: Field examples from Lost Hills, California

    Energy Technology Data Exchange (ETDEWEB)

    Wilt, M.; Schenkel, C.; Wratcher, M.; Lambert, I.; Torres-Verdin, C.; Tseng H.W.


    A steamflood recently initiated by Mobil Development and Production U.S. at the Lost Hills No 3 oil field in California is notable for its shallow depth and the application of electromagnetic (EM) geophysical techniques to monitor the subsurface steam flow. Steam was injected into three stacked eastward-dipping unconsolidated oil sands at depths from 60 to 120 m; the plume is expected to develop as an ellipsoid aligned with the regional northwest-southeast strike. Because of the shallow depth of the sands and the high viscosity of the heavy oil, it is important to track the steam in the unconsolidated sediments for both economic and safety reasons. Crosshole and surface-to-borehole electromagnetic imaging were applied for reservoir characterization and steamflood monitoring. The crosshole EM data were collected to map the interwell distribution of the high-resistivity oil sands and to track the injected steam and hot water. Measurements were made in two fiberglass-cased observation wells straddling the steam injector on a northeast-southwest profile. Field data were collected before the steam drive, to map the distribution of the oil sands, and then 6 and 10 months after steam was injected, to monitor the expansion of the steam chest. Resistivity images derived from the collected data clearly delineated the distribution and dipping structure of the target oil sands. Difference images from data collected before and during steamflooding indicate that the steam chest has developed only in the middle and lower oil sands, and it has preferentially migrated westward in the middle oil sand and eastward in the deeper sand. Surface-to-borehole field data sets at Lost Hills were responsive to the large-scale subsurface structure but insufficiently sensitive to model steam chest development in the middle and lower oil sands. As the steam chest develops further, these data will be of more use for process monitoring.

  11. Why the seismicity induced in Soultz-sous-Forêts and Gross Schoenebeck enhanced geothermal fields are so different? (Invited) (United States)

    Gaucher, E.; Kohl, T.


    In enhanced geothermal systems, hydraulic fracturing and hydraulic stimulation are techniques used to increase the reservoir permeability. Their secondary effect, the induced seismicity, is a unique means to image the fault network created or reactivated by the operations. The interpretation of the results for this latter application is however limited by the capabilities of the seismic network and by our understanding of the involved physical processes. Here, we propose to highlight systematic behaviors of the seismicity induced in enhanced geothermal reservoirs. This is performed through the analysis of two EGS sites which appear to behave very differently in terms of induced seismicity: the Soultz-sous-Forêts (France) and the Gross Schoenebeck (Germany) fields. Several physics-based models have been tested for these fields and these observations should be used to calibrate them and the underlying physical assumptions. The Soultz-sous-Forêts (France) geothermal field is located in the Upper Rhine valley. Over the development of this EGS, four wells have been drilled into the granitic basement, up to 5 km depth, and eight major stimulations were carried out to create the heat exchanger. Several major observations based on the large induced seismicity database have been made and can apply on other EGS. Hence, it was noticed that a) the induced seismicity mainly occurs along planar features, b) during stimulation, the induced seismicity becomes stronger over time and this is still observed after shut-in. Most often, the largest magnitude microearthquake occurs following shut-in, c) over a certain overpressure threshold, seismicity can be induced and also a clear Kaiser effect can be observed for already stimulated volumes, d) the stimulation and the circulation periods induce different seismic responses. At Gross Schoenebeck (Germany), the Dethlingen sandstones and the underlying andesitic volcanic rocks of the Rotliegend formation of the North German Basin

  12. Geothermal energy

    Energy Technology Data Exchange (ETDEWEB)

    White, D.E.


    The following subjects are discussed: areas of ''normal'' geothermal gradient, large areas of higher-than-''normal'' geothermal gradient, hot spring areas, hydrothermal systems of composite type, general problems of utilization, and domestic and world resources of geothermal energy. Almost all estimates and measurements of total heat flow published through 1962 for hot spring areas of the world are tabulated. (MHR)

  13. Micro-topography showing the landslide-origin of the Marumori hill, Matsukawa geothermal field Iwate Prefecture, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Tomomasa; Ikeda, Kazuo; Sumi, Seiai


    The Marumori Hill in the Matsukawa geothermal field has been previously considered to be a central cone or a lava dome in a caldera. Airphotogeological study, topographical surveying, and trenching are carried out in order to clarify the origin of the hill. Fifty six topographic linearments trending NE-SW direction distributed parallelly were detected on the top area and the northern flank of the hill. This linearment swarm is composed of the alternated small ranges and valleys with asymmetric profiles similar to cuesta topography. These topographic features are considered to be formed under the tensional stress field trending NW-SE direction on the surface of a landslide block. The hill is inferred to be not a lava dome but a landslide block which slide down from the steep scarp north and west of the hill. The age of the landslide is dated back to be older than 2400 years B.P. according to 14C age of the humic strata covering the hill. (7 figs, 1 tab, 14 refs)

  14. Configuration of the mudstones, gray- and coffee-colored shale lithologic units, zones of silica and epidote, and their relation to the tectonics of the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Cobo R, J.M.


    Based on well cuttings, five lithological units have been recognized within the area of what is now the Cerro Prieto geothermal field. These five units are described. Differences in origin, mineralogy, grading, color, compaction, etc., are shown.

  15. A study of production/injection data from slim holes and large-diameter wells at the Takigami Geothermal Field, Kyushu, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Garg, S.K. [Maxwell Federal Div., Inc., San Diego, CA (United States); Combs, J. [Geo-Hills Associates, Los Altos Hills, CA (United States); Azawa, Fumio [Idemitsu Kosan Co. Ltd., Tokyo (Japan); Gotoh, Hiroki [Idemitsu Oita Geothermal Co. Ltd., Oita (Japan)


    Production and injection data from nine slim holes and sixteen large-diameter wells at the Takigami Geothermal Field, Kyushu, Japan were analyzed in order to establish relationships (1) between injectivity and productivity indices, (2) between productivity/injectivity index and borehole diameter, and (3) between discharge capacity of slim holes and large-diameter wells. Results are compared with those from the Oguni and Sumikawa fields. A numerical simulator (WELBOR) was used to model the available discharge rate from Takigami boreholes. The results of numerical modeling indicate that the flow rate of large-diameter geothermal production wells with liquid feedzones can be predicted using data from slim holes. These results also indicate the importance of proper well design.

  16. Cost model for geothermal wells applied to the Cerro Prieto geothermal field case, BC Abstract; Modelo de costeo de pozos geotermicos aplicado para el caso del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Vaca Serrano, Jaime M.E [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail:


    A project for drilling geothermal wells to produce electrical energy can be defined as a sequence of plans to get steam or geothermal fluids to satisfy a previously known demand, and, under the best possible conditions, to obtain payment. This paper presents a cost model for nine wells drilled at the Cerro Prieto geothermal field in 2005 and 2006 to supply steam to the power plants operating in the field. The cost model is based on the well cost, the initial steam production, the annual decline of steam, the drilling schedule and the break-even point for each well. The model shows the cost of steam by the ton and the sale price needed to determine the discount rate and the investment return time. [Spanish] Un proyecto de perforacion de pozos geotermicos puede definirse como una secuencia o sucesion de planes para obtener vapor o fluidos geotermicos destinados a satisfacer una demanda previamente determinada, que se emplearan principalmente para generar energia electrica, bajo las mejores condiciones para obtener un pago. Este trabajo presenta un modelo de costeo para nueve pozos en el campo geotermico de Cerro Prieto, que fueron perforados entre 2005 y 2006 como parte del suministro de vapor para las plantas generadoras que operan en este campo. El modelo de costeo se basa en el costo por pozo, la produccion inicial de vapor, la declinacion anual de vapor, los intereses de las obras de perforacion y el punto de equilibrio para cada pozo. Los resultados permiten conocer el costo de la tonelada de vapor y el precio de venta para determinar la tasa de descuento y el tiempo de retorno de la inversion.

  17. Operation and Performance of a Biphase Turbine Power Plant at the Cerro Prieto Geothermal Field (Final Report)

    Energy Technology Data Exchange (ETDEWEB)

    Hays, Lance G. [Douglas Energy Company, Placentia, CA (United States)


    A full scale, wellhead Biphase turbine was manufactured and installed with the balance of plant at Well 103 of the Cerro Prieto geothermal resource in Baja, California. The Biphase turbine was first synchronized with the electrical grid of Comision Federal de Electricidad on August 20, 1997. The Biphase power plant was operated from that time until May 23, 2000, a period of 2 years and 9 months. A total of 77,549 kWh were delivered to the grid. The power plant was subsequently placed in a standby condition pending replacement of the rotor with a newly designed, higher power rotor and replacement of the bearings and seals. The maximum measured power output of the Biphase turbine, 808 kWe at 640 psig wellhead pressure, agreed closely with the predicted output, 840 kWe. When combined with the backpressure steam turbine the total output power from that flow would be increased by 40% above the power derived only from the flow by the present flash steam plant. The design relations used to predict performance and design the turbine were verified by these tests. The performance and durability of the Biphase turbine support the conclusion of the Economics and Application Report previously published, (Appendix A). The newly designed rotor (the Dual Pressure Rotor) was analyzed for the above power condition. The Dual Pressure Rotor would increase the power output to 2064 kWe by incorporating two pressure letdown stages in the Biphase rotor, eliminating the requirement for a backpressure steam turbine. The power plant availability was low due to deposition of solids from the well on the Biphase rotor and balance of plant problems. A great deal of plant down time resulted from the requirement to develop methods to handle the solids and from testing the apparatus in the Biphase turbine. Finally an online, washing method using the high pressure two-phase flow was developed which completely eliminated the solids problem. The availability of the Biphase turbine itself was 100

  18. Geologic field-trip guide to the Lassen segment of the Cascades Arc, northern California (United States)

    Clynne, Michael A.; Muffler, L. J. Patrick


    This field-trip guide provides an overview of Quaternary volcanism in and around Lassen Volcanic National Park, California, emphasizing the stratigraphy of the Lassen Volcanic Center. The guide is designed to be self-guided and to focus on geologic features and stratigraphy that can be seen easily from the road network.

  19. Coordinated California Corrections: Field Services--Probation and Parole. Correctional System Study. Final Report. (United States)

    California State Human Relations Agency, Sacramento. Board of Corrections.

    Correctional services can best be provided through local, community-based programs. The construction and operation of adequate field supervision services must be emphasized in California, corresponding to a de-emphasis of institutionalization. Task force reports on probation and parole are presented separately, giving extensive general and…

  20. The University of California Institute of Environmental Stress Marathon Field Studies (United States)

    Maron, Michael B.


    In 1973, the Institute of Environmental Stress of the University of California-Santa Barbara, under the direction of Steven M. Horvath, began a series of field and laboratory studies of marathon runners during competition. As one of Horvath's graduate students, many of these studies became part of my doctoral dissertation. The rationale for…

  1. Analysis of P- and S-wave VSP (vertical seismic profile) data from the Salton Sea Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Daley, T.M.


    To understand any geophysical data, geologic information is necessary. This thesis will begin with a summary of the geology of the Salton Trough region and the Salton Sea Geothermal Field (SSGF). The information available from the SSSDP will also be summarized. After the geologic summary, the design of the VSP will be discussed, including acquisition equipment and procedures. The data processing procedures and software used will be discussed as a separate section. Processing procedures will also be described at various times in the thesis where more specialized procedures are used. Data analysis makes up the bulk of the thesis and it is divided into a number of sections detailing the basic VSP interpretation, the anisotropy analysis and the fracture detection and orientation analysis. A combined interpretation of the results, with probable geologic causes for observed events, is presented as a separate section from the data analysis. Finally, a summary of results for each of the goals stated above will be given. The reader should note that a large volume of data were collected and various display methods were used (from the standard wiggle-trace to three-component hodographs). Much of these data are left in the appendices with important or representative figures given in the body of the thesis. Also given in the appendices are listings of FORTRAN programs developed in conjunction with the thesis work. 46 refs., 63 figs., 12 tabs.

  2. Application of geochemical techniques to deduce the reservoir performance of the Palinpinon Geothermal Field, Philippines - an update

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Candelaria, M.N.; Garcia, S.E.; Hermoso, D.Z. [PNOC-Energy Development Corp., Makati City (Philippines)] [and others


    Regular monitoring of various geochemical parameters in the water and vapor phases of the production wells at the Palinpinon I and II sectors of the Southern Negros Geothermal Field have been useful in the identification of the dominant reservoir processes occurring related to the present exploitation strategy. Observed geochemical and physical changes in the output of production wells have dictated production and injection strategies adopted to maximize production to meet the steam requirements of the power plant. Correlation of both physical and chemical data have identified the following reservoir processes: (1) Injection breakthrough via the Ticala Fault of the highly mineralized (Cl {approximately}8,000-10,500 mg/kg), isotopically enriched ({delta}{sup 18}O = -3.00{per_thousand}, {delta}{sup 2} H = -39{per_thousand}), and gas depleted brine for wells in the SW and central Puhagan. Injection breakthrough is also occurring in Palinpinon II and has resulted in temperature drops of 5-10{degrees}C.2. Pressure drawdown enhanced boiling in the liquid reservoir with steam separation of 220-240{degrees}C, feeding wells tapping the natural steam zone. However, enhanced drawdown has induced the entry of shallow acid steam condensate fluids in some wells (e.g. OK-7, PN-29D, PN-18D), which if not arrested could reduce production.

  3. Geothermal Energy. (United States)

    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.…

  4. Geothermal Energy

    Energy Technology Data Exchange (ETDEWEB)

    Steele, B.C.; Pichiarella, L.S. [eds.; Kane, L.S.; Henline, D.M.


    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.

  5. Geopressured geothermal bibliography (Geopressure Thesaurus)

    Energy Technology Data Exchange (ETDEWEB)

    Hill, T.R.; Sepehrnoori, K.


    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.

  6. Studies for recovering injection capacity in wells of the Cerro Prieto, BC, geothermal field; Estudios para recuperar la capacidad de aceptacion en pozos inyectores del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Rosales, Julio [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail:


    As in geothermal fields around the world, at Cerro Prieto geothermal field, Baja California, former exploratory and production wells are used to inject residual brine. Since the 1980s, studies and activities have been carried out to find ways to recharge the reservoir and dispose of brine without harming the environment or underground aquifers. These include infiltration and cold-and-hot injection. Some of the studies are presented here, including analyses of litho-facies; core samples; pressure, temperature and spinner logs; well tests and injection rates-plus some studies on the shallow aquifer. All have been useful in fulfilling requirements made by environmental authorities. Because injection rates constantly decrease due to formation damage, it is proposed an additional technique be used to reduce such damages and prolong the lifetime of cold-and-hot injection wells-while ensuring the environment and shallow aquifers are not affected. [Spanish] Al igual que en diversos campos geotermicos en el mundo, en el de Cerro Prieto, Baja California se han utilizado tanto pozos inyectores perforados ex profeso como antiguos pozos exploratorios y productores para inyectar el fluido residual al subsuelo. Desde la decada de los 80 se han realizado diversos estudios y acciones en ese campo geotermico para recargar al yacimiento y para disponer del fluido residual, sin ocasionar danos al ambiente ni a los cuerpos hidricos del subsuelo, que van desde la infiltracion hasta la inyeccion en frio y en caliente. Este articulo presenta los diferentes estudios realizados con ese objetivo en el campo, incluyendo el analisis de litofacies, de nucleos de formacion, de registros de presion, temperatura y spinner, las pruebas en pozos y analisis de tasas de aceptacion, asi como los efectuados en el acuifero superficial. Todos ellos han sido de utilidad para atender los requerimientos de las autoridades ambientales. Finalmente, y en virtud de que las tasas de aceptacion de los pozos

  7. A Study of Production/Injection Data from Slim Holes and Large-Diameter Wells at the Okuaizu Geothermal Field, Tohoku, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Renner, Joel Lawrence; Garg, Sabodh K.; Combs, Jim


    Discharge from the Okuaizu boreholes is accompanied by in situ boiling. Analysis of cold-water injection and discharge data from the Okuaizu boreholes indicates that the two-phase productivity index is about an order of magnitude smaller than the injectivity index. The latter conclusion is in agreement with analyses of similar data from Oguni, Sumikawa, and Kirishima geothermal fields. A wellbore simulator was used to examine the effect of borehole diameter on the discharge capacity of geothermal boreholes with two-phase feedzones. Based on these analyses, it appears that it should be possible to deduce the discharge characteristics of largediameter wells using test data from slim holes with two-phase feeds.

  8. Gas geochemistry of Los Humeros geothermal field, Mexico; Geoquimica de gases del campo geotermico de Los Humeros, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Barragan R, Rosa Maria; Arellano G, Victor M; Nieva G, David; Portugal M, Enrique; Garcia G, Alfonso; Aragon A, Alfonso [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico); Torres A, Ignasio S [Centro de Investigacion en Energia, Temixco, Morelos (Mexico); Tovar A, Rigoberto [Comision Federal de Electricidad, Los Humeros, Puebla (Mexico)


    Gas data of Los Humeros geothermal field were analyzed. A new method, which is based on the Fischer-Tropch reactions and on the combined pyrite-magnetite mineral equilibrium, was used. Reservoir temperature and reservoir excess steam were estimated for the starting stage of the field by using early data taken from producing wells at controlled conditions. The same parameters were also obtained for the present stage by using 1997 gas data. Reservoir temperatures ranged from 275 and 337 Celsius degrees and positive values for reservoir excess steam fractions were obtained for the starting stage. For well H-1 no excess steam was found since this well was fed by the shallower liquid-dominated reservoir. Results for 1997 showed lower scattering compared to early data and the possible occurrence of a heating process in the shallower stratum which could due to exploitation. [Spanish] En este articulo se presenta un analisis de datos de la fase gaseosa producida por pozos productores del campo geotermico de Los Humeros mediante un metodo que considera el equilibrio de la reaccion de Fischer-Tropsh y el equilibrio de minerales pirita-hematia y pirita-magnetita. Este metodo provee la temperatura del yacimiento y el exceso de vapor presente en la descarga total de los pozos. Los resultados se discuten tanto para el estado inicial del yacimiento utilizando los primeros datos de produccion en los que el flujo del pozo estuvo controlado y los obtenidos en 1997 que representan el estado actual del yacimiento. En el estado inicial se estimaron temperaturas de yacimiento de entre 275 y 337 grados Celsius y excesos de vapor positivos, con excepcion del pozo H-1 que se alimenta del estrato somero dominado por liquido. Los resultados obtenidos para 1997 muestran una dispersion menor y la probable ocurrencia de un proceso de calentamiento del estrato somero propiciado por la explotacion.

  9. Study of the Crossborder Geothermal Field in the Sarandoporos- Konitsa Area With Integrated Geophysical and Geochemical Methods. (United States)

    Tsokas, G.; Balliu, E.; Reci, H.


    The studied area lies north of the city of Konitsa in Greece and includes the Albanian village of Koukes. Specifically, it lies between the geographic latitude (ö) 40ï 02' up to 40ï 07' and in geographic longitude (ë) 20ï 37' up to 20ï 45'. The geothermic field in Sarandaporos -Konitsa lies in the cross-border area between Albania and Greece. The field has several surface manifestations and extended geological investigations, including tectonic geochemical and geomorfological studies have been carried out. This work presents the conduct and interpretation of vertical electrical soundings (V.E.S.) in both sides of the borders. It is aiming to study the structure down to the depth of 1000m, in a relative large area, where information about the deep structure would have an enormous cost if acquired by a network of boreholes. Thermal springs known in the Greek part of the region are the thermal springs of Kavassila - Piksaria where the water temperature reaches up to 31o C. In the Albanian side the existence of hot springs (Koukes) is also well known, where the water supply is provided by the hot springs situated in the Skordili bridge. Two main geoelectrical formations revealed which coincide with the flysch and the limestone basement. The area appears faulted in the NW-SE and NE-SW directions and a few concealed graben and horst structures exist. Low resistivity values were observed above basement uplifts and major faults. These values were attributed to hot fluid circulation.

  10. Basalt models for the Mars penetrator mission: Geology of the Amboy Lava Field, California (United States)

    Greeley, R.; Bunch, T. E.


    Amboy lava field (San Bernardino County, California) is a Holocene basalt flow selected as a test site for potential Mars Penetrators. A discussion is presented of (1) the general relations of basalt flow features and textures to styles of eruptions on earth, (2) the types of basalt flows likely to be encountered on Mars and the rationale for selection of the Amboy lava field as a test site, (3) the general geology of the Amboy lava field, and (4) detailed descriptions of the target sites at Amboy lava field.

  11. Alkaline flood prediction studies, Ranger VII pilot, Wilmington Field, California

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, E.H.; Breit, V.S.


    The paper discusses: (1) The design of a simulator to model alkaline displacement mechanisms and the current state-of-the-art understanding of in-situ caustic consumption. (2) Assimilation of laboratory core flood and rock consumption data. Use of this data in 1-D and 2-D limited area simulations, and a 3-D model of the entire pilot project. (3) Simulation studies of alkaline flood behavior in a small 2-D area of the field for various concentrations, slug sizes, long term consumption functions and two relative permeability adjustment mechanisms. (4) Scale up of 2-D simulation results, and their use in a 271 acre 1.097 x 10/sup 6/m/sup 2/), 7 layered 3-D model of the pilot. (5) Comparison of 3-D simulator results with initial field alkaline flood performance. (6) Recommended additional application of the simulator methods developed in this pilot and in other alkaline floods. 10 refs.

  12. A Status Report on the Exploitation Conditions of the Ahuachapan Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Rivera-R., Jesus; Vides-R., Alberto; Cuellar, Gustavo; Samaniego-V., Fernando; Neri-I, Gustavo


    The present exploitation conditions of the Ahuachapan field are discussed. The high well density in a small area has resulted in a significant reservoir pressure decrease due to the inherent reservoir over-exploitation. The average pressure in the exploitation zone has decreased from the 1975 value of 34 kg/cm{sup 2} to the May 1983 value of 23 kg/cm{sup 2}. The production decline characteristics of the Ahuachapan wells were examined, concluding that all wells but Ah-22 show exponential decline. The cumulative production-reinjection for the field up to April 1983 is 159.090 x 10{sup 6} tons, and 37.592 x 10{sup 6} tons, respectively. The effect of reinjection upon field behavior is evident when observing the pressure decline characteristics of the field. It is seen that for indection fraction related to total mass extracted above 30 percent, the average decline pressure in the production area becomes approximately stabilized. If this condition is not met the reservoir pressure decreases sharply. From this finding it is concluded that a careful and properly planned reinjection program is a must for the field. The observed temperature reduction in some of the wells seems to be the result of two operating mechanisms. First, we have the pressure decline that produces water vaporization and the consequent temperature descend. Analysis of information available shows no clear indication of deleterious temperature effects on the producing wells due to injection. The only exception observed to date is well Ah-5 that because its close distance and its relative structural position and direct hydraulic connection to injector Ah-29, presented conditions for fast displacement of the thermal front, resulting in unsufficient contact area and residence time for reheating of the injected water.

  13. Analysis of two catalogues of seismicity at the Cerro Prieto geothermal area (Baja California) from 1988 to 1995, relationship with reinjection; Analisis de dos catalogos de sismicidad en el area geotermica de Cerro Prieto (Baja California) de 1988 a 1995, relacion con la reinyeccion

    Energy Technology Data Exchange (ETDEWEB)

    Fabriol, Hubert [Centro de Investigacion y de Ensenanza Superior de Ensenada (CICESE), Ensenada (Mexico)


    In order to study the effects of fluid reinjection in the Cerro Prieto geothermal field, started in 1989, seismicity recorded in this area and included in the USGS-Caltech (California Technology) (US) and the Red Sismologica del Noreste de Mexico (RESNOM) of the Centro de Investigacion Cientifica y de Ensenanza Superior (CICESE, Mexico) catalogues is reviewed since 1988. The precision of determination of epicenters is compared with the location of moderate events recorded by a local array, setup around Cerro Prieto since August 1994. We note a bias in both catalogues, as events located by USGS-Caltech are shifted between 5 to 10 km towards south and events of RESNOM are shifted between 4 to 8 km towards northeast. That limits the use of these catalogues for precise studies of reinjection effects in the geothermal field. Seismic activity is low until 1991 and increases afterwards, particularly in 1993 and 1995. Comparison of USGS-Caltech catalogue with changes in reinjection flow rates show at beginning of 1995 only one example of short-range effect between reinjection and seismicity (but using the epicenter determination of the local network) and possibly several medium-range effects (between 6 and 8 months). In that case, the flow rate increase corresponding to the beginning of winter, could be followed by one or more events of magnitude ranging from Ml=3 to Ml=4 during midsummer. Taking into account the tectonic context of the area, it is also possible that those event could be associated either to Cerro Prieto fault or to the spreading center source of the thermal anomaly. The continuous monitoring with a local network will allow to precise those preliminary results, obtained with regional networks. [Espanol] Como parte del estudio sobre los efectos de la reinyeccion de fluido en el campo geotermico de Cerro Prieto, iniciado en 1989, se analiza de manera critica la sismicidad registrada en el area y reportada en los catalogos de USGS-Caltech (Tecnologico de

  14. Geothermal industry assessment

    Energy Technology Data Exchange (ETDEWEB)


    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)

  15. Rapid, high-temperature, field test method for evaluation of geothermal calcium carbonate scale inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G.


    A new test method is described that allows the rapid field testing of calcium carbonate scale inhibitors at 500/sup 0/F (260/sup 0/C). The method evolved from use of a full-flow test loop on a well with a mass flow rate of about 1 x 10/sup 6/ lbm/hr (126 kg/s). It is a simple, effective way to evaluate the effectiveness of inhibitors under field conditions. Five commercial formulations were chosen for field evaluation on the basis of nonflowing, laboratory screening tests at 500/sup 0/F (260/sup 0/C). Four of these formulations from different suppliers controlled calcium carbonate scale deposition as measured by the test method. Two of these could dislodge recently deposited scale that had not age-hardened. Performance-profile diagrams, which were measured for these four effective inhibitors, show the concentration interrelationship between brine calcium and inhibitor concentrations at which the formulations will and will not stop scale formation in the test apparatus. With these diagrams, one formulation was chosen for testing on the full-flow brine line. The composition was tested for 6 weeks and showed a dramatic decrease in the scaling occurring at the flow-control valve. This scaling was about to force a shutdown of a major, long-term flow test being done for reservoir economic evaluations. The inhibitor stopped the scaling, and the test was performed without interruption.

  16. Alkaline flood prediction studies, Ranger VII pilot, Wilmington Field, California

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, E.H.; Breit, V.S.


    This paper discusses the design of a simulator to model alkaline displacement mechanisms, along with the current understanding of in-situ caustic consumption. Assimilation of laboratory coreflood and rock consumption data, and their use in one- and two-dimensional (1D and 2D) limited area simulations and in three-dimensional (3D) models of the entire pilot project are given. This paper also reports simulation studies of alkaline flood behavior in a small 2D area of a field for various concentrations, slug sizes, long-term consumption functions, and two relative-permeability adjustment mechanisms. The scale-up of 2D simulation results and their use in a 271-acre (1096.7-ha), seven-layered, 3D model of the pilot are also discussed and 3D simulator results are compared with initial field alkaline flood performance. Finally, recommended additional applications of the simulator methods developed in this pilot and in other alkaline floods are discussed.

  17. The potential of audiomagnetotellurics in the study of geothermal fields: A case study from the northern segment of the La Candelaria Range, northwestern Argentina (United States)

    Barcelona, Hernan; Favetto, Alicia; Peri, Veronica Gisel; Pomposiello, Cristina; Ungarelli, Carlo


    Despite its reduced penetration depth, audiomagnetotelluric (AMT) studies can be used to determine a broad range of features related to little studied geothermal fields. This technique requires a stepwise interpretation of results taking into consideration diverse information (e.g. topographic, hydrological, geological and/or structural data) to constrain the characteristics of the study area. In this work, an AMT study was performed at the hot springs in the northern segment of the La Candelaria Range in order to characterize the area at depth. Geometric aspects of the shallow subsurface were determined based on the dimensional and distortion analysis of the impedance tensors. Also, the correlation between structural features and regional strikes allowed us to define two geoelectric domains, useful to determine the controls on fluid circulation. The subsurface resistivity distribution was determined through 1D and 2D models. The patterns of the 1D models were compared with the morpho-structure of the range. Shallow and deep conductive zones were defined and a possible shallow geothermal system scheme proposed. A strong correlation was found between the AMT results and the geological framework of the region, showing the relevance of using AMT in geothermal areas during the early stages of subsurface prospecting.

  18. Modelling the effect of fractures in geothermal reservoirs on the seismic wave field - anisotropy, scattering and localisation (United States)

    Möller, Thomas; Friederich, Wolfgang


    Fractures and cracks in rocks have a significant influence on the propagation of seismic waves. Their presence causes reflections and scattering of the waves and generates effective anisotropy within the rocks. In geothermics, gaining information on how a system of fractures affects the wave field is of great importance for reservoir characterisation. We present a numerical approach to the simulation of seismic wave propagation in fractured media that does not require explicit modelling of the fracture itself, but uses the concept of linear slip interfaces developed by Schoenberg (1980). This concept states that at an interface between two imperfectly bonded elastic media, stress is continuous across the interface while displacement is discontinuous. It is assumed that the jump of displacement is proportional to stress which implies a jump in particle velocity at the interface. We use this concept as a boundary condition to the elastic wave equation and solve this equation in the framework of a Nodal Discontinuous Galerkin scheme using a velocity-stress formulation. The concept of linear slip interfaces has been implemented into the 1D and 2D versions of the discontinuous Galerkin solver "NEXD". We verified the implementation for the case of an elastic linear slip interface. We use this concept to demonstrate the effect of fractures by the following examples: (1) A system of parallel fractures embedded in a homogenous background medium with a source in the center of the system and (2) varyingly oriented fracture systems embedded in a sample reservoir with layered velocity structure. We show that waves traveling perpendicular to the fractures experience high attenuation whereas waves traveling parallel to the fractures are almost not influenced. Synthetic seismograms show a distinct change in curvature of the wavefront when fractures are present, underlining the effective anisotropy caused by the fractures. In addition we show the contribution such systems have to

  19. An Environmental Assessment of Proposed Geothermal Well Testing in the Tigre Lagoon Oil Field, Vermilion Parish, Louisiana

    Energy Technology Data Exchange (ETDEWEB)



    This report is an environmental assessment of the proposed testing of two geopressured, geothermal aquifers in central coastal Louisiana. On the basis of an analysis of the environmental setting, subsurface characteristics, and the proposed action, potential environmental impacts are determined and evaluated together with potential conflicts with federal, state, and local programs. Oil and gas wells in coastal Louisiana have penetrated a potentially productive geothermal zone of abnormally high-pressured aquifers that also yield large volumes of natural gas. To evaluate the extent to which the geothermal-geopressured water can be used as an alternative energy source and to what extent withdrawal of geopressured water can enhance gas production, it is necessary that flow rates, composition and temperature of fluids and gases, recharge characteristics, pressures, compressibilities, and other hydrodynamic and boundary conditions of the reservoir be determined by means of production tests. Tests are further necessary to evaluate and seek solutions to technological problems.

  20. Geologic field-trip guide to Long Valley Caldera, California (United States)

    Hildreth, Wes; Fierstein, Judy


    This guide to the geology of Long Valley Caldera is presented in four parts: (1) An overview of the volcanic geology; (2) a chronological summary of the principal geologic events; (3) a road log with directions and descriptions for 38 field-trip stops; and (4) a summary of the geophysical unrest since 1978 and discussion of its causes. The sequence of stops is arranged as a four-day excursion for the quadrennial General Assembly of the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI), centered in Portland, Oregon, in August 2017. Most stops, however, are written freestanding, with directions that allow each one to be visited independently, in any order selected.

  1. Intersecting faults and sandstone stratigraphy at the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Vonder Haar, S.; Howard, J.H.


    The northwest-southeast trending Cerro Prieto fault is part of a major regional lineament that extends into Sonaro and has characteristics of both a wrench fault and an oceanic transform fault. The distribution of lithologies and temperature within the field was studied by comparing data from well cuttings, cores, well logs, and geochemical analyses. Across the earliest developed portion of the field, in particular along a 1.25-km northeast-southwest section from well M-9 to M-10, interesting correlations emerge that indicate a relationship among lithology, microfracturing, and temperature distribution. In the upper portion of Reservoir A of this stratigraphic section, between 1200 and 1400 m, the percentage of sandstones ranges from 20 to 55. Temperatures are 225/sup 0/ to 275/sup 0/C based on well logs, calcite isotope maxima, and Na-K-Ca indices. The study shows that an isothermal high in this vicinity corresponds to the lowest total percentage of sandstones. Scanning electron microphotographs of well cores and cuttings from sandstone and shale units reveal clogging, mineral dissolution, and mineral precipitation along microfractures. The working hypothesis is that these sandy shale and siltstone facies are most amenable to increased microfracturing and, in turn, such microfracturing allows for higher temperature fluid to rise to shallower depths in the reservoir.

  2. Gas chemistry and thermometry of the Cerro Prieto, Mexico, geothermal field (United States)

    Nehring, N.L.; D'Amore, F.


    Gas compositions of Cerro Prieto wells in 1977 reflected strong boiling in the reservoir around wells M-20 and M-25. This boiling zone appeared to be collapsing in 1982 when a number of wells in this area of the field were shut-in. In 1977 and 1982, gas compositions also showed boiling zones corresponding to faults H and L postulated by Halfman et al. (1982). Four gas geothermometers were applied, based on reservoir equilibria and calculated fugacities. The Fisher - Tropsch reaction predicted high temperatures and appeared to re-equilibrate slowly, whereas the H2S reaction predicted low temperatures and appeared to re-equilibrate rapidly. Hydrogen and NH3 reactions were intermediate. Like gas compositions, the geothermometers reflected reservoir processes, such as boiling. Surface gas compositions are related to well compositions, but contain large concentrations of N2 originating from air dissolved in groundwater. The groundwater appears to originate in the east and flow over the production field before mixing with reservoir gases near the surface. ?? 1984.

  3. Dipole-dipole resistivity monitoring at the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

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


    Two 20 km-long dipole-dipole lines with permanently emplaced electronics at 1-km spacings were established over the field area; one of these lines is remeasured annually. Resistivity measurements are taken using a 25 kW generator capable of up to 80A output and a microprocessor-controlled signal-averaging receiver; this high power-low noise system is capable of highly accurate measurements even at large transmitter-receiver separations. Standard error calculations for collected data indicate errors less than 5% for all points, but 95% confidence intervals show error limits about 2 to 4 times higher. Data indicate little change of apparent resistivity within the upper 300 m over the field. However, apparent resistivity increases are observed over the producing zone at depths of 1 km and greater. Large zones of decreasing apparent resistivity are observed flanking the zone of increases on both sides. To explain the resistivity changes observed, simple two-dimensional reservoir simulations were performed in which cooler, less saline recharge water enters the reservoir from above through a leaky caprock and laterally through a more permeable vertical boundary. The calculated magnitude of a resistivity change after 3 years of simulated production fits the observed data, but the anomaly shapes differ. It is concluded that the rapidly moving hydraulic front produces a salinity change large enough to explain the resistivity increase, but that our recharge assumptions were probably oversimplified.

  4. Proceedings of the second United Nations symposium on the development and use of geothermal resources held at San Francisco, California, May 20--29, 1975. Volume 1

    Energy Technology Data Exchange (ETDEWEB)


    The 299 papers in the Proceedings are presented in three volumes and are divided into twelve sections, each section dealing with a different aspect of geothermal energy. Rapporturs' summaries of the contents of each section are grouped together in Vol. 1 of the Proceedings; a separate abstract was prepared for each summary. Volume 1 also contains ninety-eight papers under the following section headings: present status of resources development; geology, hydrology, and geothermal systems; and geochemical techniques in exploration. Separate abstracts were prepared for ninety-seven papers. One paper was previously abstracted for ERA and appeared as CONF-750525--17. (LBS)

  5. Geothermal energy

    Directory of Open Access Journals (Sweden)

    Manzella A.


    Full Text Available Geothermal technologies use renewable energy resources to generate electricity and direct use of heat while producing very low levels of greenhouse-gas (GHG emissions. Geothermal energy is the thermal energy stored in the underground, including any contained fluid, which is available for extraction and conversion into energy products. Electricity generation, which nowadays produces 73.7 TWh (12.7 GW of capacity worldwide, usually requires geothermal resources temperatures of over 100 °C. For heating, geothermal resources spanning a wider range of temperatures can be used in applications such as space and district heating (and cooling, with proper technology, spa and swimming pool heating, greenhouse and soil heating, aquaculture pond heating, industrial process heating and snow melting. Produced geothermal heat in the world accounts to 164.6 TWh, with a capacity of 70.9 GW. Geothermal technology, which has focused for decades on extracting naturally heated steam or hot water from natural hydrothermal reservoirs, is developing to more advanced techniques to exploit the heat also where underground fluids are scarce and to use the Earth as a potential energy battery, by storing heat. The success of the research will enable energy recovery and utilization from a much larger fraction of the accessible thermal energy in the Earth’s crust.

  6. Geothermal energy (United States)

    Manzella, A.


    Geothermal technologies use renewable energy resources to generate electricity and direct use of heat while producing very low levels of greenhouse-gas (GHG) emissions. Geothermal energy is the thermal energy stored in the underground, including any contained fluid, which is available for extraction and conversion into energy products. Electricity generation, which nowadays produces 73.7 TWh (12.7 GW of capacity) worldwide, usually requires geothermal resources temperatures of over 100 °C. For heating, geothermal resources spanning a wider range of temperatures can be used in applications such as space and district heating (and cooling, with proper technology), spa and swimming pool heating, greenhouse and soil heating, aquaculture pond heating, industrial process heating and snow melting. Produced geothermal heat in the world accounts to 164.6 TWh, with a capacity of 70.9 GW. Geothermal technology, which has focused for decades on extracting naturally heated steam or hot water from natural hydrothermal reservoirs, is developing to more advanced techniques to exploit the heat also where underground fluids are scarce and to use the Earth as a potential energy battery, by storing heat. The success of the research will enable energy recovery and utilization from a much larger fraction of the accessible thermal energy in the Earth's crust.

  7. Reservoir geology of Landslide field, southern San Joaquin basin, California

    Energy Technology Data Exchange (ETDEWEB)

    Carr, T.R.; Tucker, R.D.; Singleton, M.T. (ARCO Oil and Gas Co., Bakersfield, CA (United States))


    The Landslide field, which is located on the southern margin of the San Joaquin basin, was discovered in 1985 and consists of 13 producers and six injectors. Cumulative production as of mid-1990 was approximately 10 million bbl of oil with an average daily production of 4700 BOPD. Production is from a series of late Miocene turbidite sands (Stevens Sand) that were deposited as a small constructional submarine fan (less than 2 mi in diameter). Based on interpretation of wireline logs and engineering data, deposition of the fan and of individual lobes within the fan was strongly influenced by preexisting paleotopography and small syndepositional slump features. Based on mapping of individual depositional units and stratigraphic dipmeter analysis, transport direction of the sand was to the north-north across these paleotopographic breaks in slope. Dipmeter data and pressure data from individual sands are especially useful for recognition and mapping of individual flow units between well bores. Detailed engineering, geophysical and geological studies have increased our understanding of the dimensions, continuity, geometry, and inherent reservoir properties of the individual flow units within the reservoir. Based on the results of these studies a series of water isolation workovers and extension wells were proposed and successfully undertaken. This work has increased recoverable reserves and arrested the rapid production decline.

  8. Performance history of the Geysers steam field, California, USA

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, K.P.; Conant, T.T. [Calpine Corporation, 10350 Socrates Mine Road, Middletown, CA 95461 (United States)


    The performance of Calpine's Geysers steam field from startup in 1960 to 2008 is described in this paper. Since October 2003, Calpine has received approximately 482 L/s of tertiary-treated reclaimed water from the City of Santa Rosa. To accommodate and derive benefit from this water, Calpine has converted 20 wells (ten producers, six shut-in, two observation, and two suspended wells) to high-rate injection service. Additional nine wells were also converted to low-rate injectors that receive 12.6 L/s or less. Annual recovery factors (i.e., fieldwide increase in annual steam production divided by annual injection) for the first 5 years of Santa Rosa Geysers Recharge Project (SRGRP) operation have been estimated at 17.6%, 26.1%, 37.1%, 39% and 44.6%, respectively; reasonably close to or slightly higher than the values, predicted prior to SRGRP startup. Using a revised definition that includes the amount of un-boiled water in the reservoir, the annual recovery factors turn out to be 17.6%, 16.1%, 14.6%, 12.4% and 12.2% from year one through year five. Improvements in the wellfield, water injection, and power plant modifications from January 1995 through December 2008 are also discussed in this paper. (author)

  9. Dissipation of the Herbicide Benzobicyclon Hydrolysate in a Model California Rice Field Soil. (United States)

    Williams, Katryn L; Gladfelder, Joshua J; Quigley, Lindsay L; Ball, David B; Tjeerdema, Ronald S


    The herbicide benzobicyclon (BZB; 3-(2-chloro-4-(methylsulfonyl)benzoyl)-2-phenylthiobicyclo[3.2.1]oct-2-en-4-one) has recently been approved for use on California rice fields by the United States Environmental Protection Agency (U.S. EPA). Hydrolysis of BZB rapidly forms the active compound, benzobicyclon hydrolysate (BH), whose fate is currently not well understood. A model California rice soil was used to determine BH soil dissipation. The pKa and aqueous solubility were also determined, as experimental values are not currently available. Sorption data indicate BH does not bind tightly, or irreversibly, with this soil. Flooding resulted in decreased BH loss, indicating anaerobic microbes are less likely to transform BH compared to aerobic microorganisms. Temperature increased dissipation, while autoclaving decreased BH loss. Overall, dissipation was slow regardless of treatment. Further investigation is needed to elucidate the exact routes of loss in soil, though BH is expected to dissipate slowly in flooded rice field soil.

  10. Geothermal resource development: laws and regulations

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, J.C.


    The development of geothermal resources in California is becoming of increasing interest because of the large amounts of these resources in the state. In response to this interest in development, the legislature and regulatory bodies have taken actions to increase geothermal power production. The important federal and California laws on the subject are presented and discussed. Pertinent federal and state provisions are compared, and inconsistencies are discussed. An important concept that needs clarification is the manner of designating an area as a ''known geothermal resource area.'' The question of designating geothermal resource as a mineral is not completely resolved, although there is authority tending toward the finding that it is a mineral.

  11. Petrophysical Properties of Twenty Drill Cores from the Los Azufres, Mexico, Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, E.R.; Contreras L., E.; Garcia G., A.; Dominquez A., Bernardo


    For this study we selected 20 drill cores covering a wide range of depths (400-3000 m), from 15 wells, that provide a reasonable coverage of the field. Only andesite, the largely predominant rock type in the field, was included in this sample. We measured bulk density, grain (solids) density, effective porosity and (matrix) permeability on a considerable number of specimens taken from the cores; and inferred the corresponding total porosity and fraction of interconnected total porosity. We characterized the statistical distributions of the measured and inferred variables. The distributions of bulk density and grain density resulted approximately normal; the distributions of effective porosity, total porosity and fraction of total porosity turned out to be bimodal; the permeability distribution resulted highly skewed towards very small (1 mdarcy) values, though values as high as 400 mdarcies were measured. We also characterized the internal inhomogeneity of the cores by means of the ratio (standard deviation/mean) corresponding to the bulk density in each core (in average there are 9 specimens per core). The cores were found to present clearly discernible inhomogeneity; this quantitative characterization will help design new experimental work and interpret currently available and forthcoming results. We also found statistically significant linear correlations between total density and density of solids, effective porosity and total density, total porosity and total density, fraction of interconnected total porosity and the inverse of the effective porosity, total porosity and effective porosity; bulk density and total porosity also correlate with elevation. These results provide the first sizable and statistically detailed database available on petrophysical properties of the Los Azufres andesites. 1 tab., 16 figs., 4 refs.

  12. Mexican geothermal development and the future

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, J.M.E.V. [Comision Federal de Electricidad, Morelia (Mexico)


    Geothermics in Mexico started in 1954, by drilling the first geothermal well in Pathe, State of Hidalgo, which reached a depth of 237 meters. In 1959 electrical generation from geothermal origin began, with an installed capacity of 3.5 MW. From 1959 to 1994 Mexico increased its installed capacity to 753 MW, by developing three geothermal fields: Cerro Prieto, Los Azufres, and Los Humeros. Currently, 177 wells produce steam at a rate of 36 tons per hour (t/h) each. Comision Federal de Electricidad (CFE, Federal Commission of Electricity) has planned to increase the geothermal-electric installed capacity through construction and installation of several projects. Repowering of operating units and development of new geothermal zones will also allow Mexican geothermal growth.

  13. World Geothermal Congress WGC-2015 (United States)

    Tomarov, G. V.; Shipkov, A. A.


    This article discusses materials and results of the World Geothermal Congress that was held in Melbourne (Australia) from April 19 to April 25, 2015. Information on the extent and technological features of utilization of geothermal resources for heat supply and power production, as well as in other economic areas, is given. A stable growth in the capacity and number of geothermal power systems that is determined by ecological cleanliness, economic efficiency, and the highest (among renewable energy sources) indicators of installed capacity utilization is shown. It was noted that combined schemes of geothermal power plants (GPPs), such as turbine units of different type (binary units, units with one or two separation pressures, etc.), have become more frequently used to increase the efficiency of utilization of geothermal heat carrier. Actual data determining room heating systems with the total worldwide capacity of nearly 50000 MW thermal (MWt) as the most currently significant segment of consumption of geothermal waters are given. In addition, geothermal resources are also utilized in soil pumps, balneological and sports basins, greenhouse complexes, and other manufactures. It was noted that geological studies were carried out in more than 40 countries, with the development of methods of simulation of tanks for the existing and new geothermal fields. Trends of development and the role of geothermal power engineering in the energy supply of many countries are shown. It was shown that prospects for the development of geothermal power generation are significantly associated with utilization of low-temperature geothermal sources in binary power generating units, as well as with the increase in installed capacity of operating geothermal power plants (GPPs) without drilling additional wells, i.e., by using waste geothermal heat carrier in binary-cycle or combined-cycle power plants. The article provides data on a pilot binary power unit at Pauzhetka GPP and on a

  14. Balancing energy and the environment: the case of geothermal development

    Energy Technology Data Exchange (ETDEWEB)

    Ellickson, P.L.; Brewer, S.


    The results of part of a Rand study on the federal role in resolving environmental issues arising out of the implementation of energy projects are reported. The projects discussed are two geothermal programs in California: the steam resource development at The Geysers (Lake and Sonoma counties) in northern California, and the wet brine development in the Imperial Valley in southern California.

  15. Silicon isotope fractionation during silica precipitation from hot-spring waters: Evidence from the Geysir geothermal field, Iceland

    NARCIS (Netherlands)

    Geilert, S.; Vroon, P.Z.; Keller, N.S.; Gudbrandsson, S.; Stefánsson, A.; van Bergen, M.J.


    This study aims to explore the extent and controls of silicon isotope fractionation in hot spring systems of the Geysir geothermal area (Iceland), a setting where sinter deposits are actively formed. The δ30Si values of dissolved silica measured in the spring water and sampling sites along

  16. Silicon isotope fractionation during silica precipitation from hot-spring waters : Evidence from the Geysir geothermal field, Iceland

    NARCIS (Netherlands)

    Geilert, Sonja; Vroon, Pieter Z.; Keller, Nicole S.; Gudbrandsson, Snorri; Stefánsson, Andri; van Bergen, Manfred J.


    This study aims to explore the extent and controls of silicon isotope fractionation in hot spring systems of the Geysir geothermal area (Iceland), a setting where sinter deposits are actively formed. The δ30Si values of dissolved silica measured in the spring water and sampling sites along

  17. Geothermal overviews of the western United States

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, D.N.; Axtell, L.H. (comps.)


    This compendium presents data on geothermal resources for all those western states with geothermal potential. Individual sections, which have been processed separately for inclusion in the EDB data base, are devoted to each of the following states: Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming. A separate section is also devoted to the U.S. Bureau of Reclamation Imperial Valley Project. Maps and references are included for each section. (JGB)

  18. Geothermal areas as analogues to chemical processes in the near-field and altered zone of the potential Yucca Mountain, Nevada repository

    Energy Technology Data Exchange (ETDEWEB)

    Bruton, C.J.; Glassley, W.E.; Meike, A.


    The need to bound system performance of the potential Yucca Mountain repository for thousands of years after emplacement of high-level nuclear waste requires the use of computer codes. The use of such codes to produce reliable bounds over such long time periods must be tested using long-lived natural and historical systems as analogues. The geothermal systems of the Taupo Volcanic Zone (TVZ) in New Zealand were selected as the site most amenable to study. The rocks of the TVZ are silicic volcanics that are similar in composition to Yucca Mountain. The area has been subjected to temperatures of 25 to 300 C which have produced a variety of secondary minerals similar to those anticipated at Yucca Mountain. The availability of rocks, fluids and fabricated materials for sampling is excellent because of widespread exploitation of the systems for geothermal power. Current work has focused on testing the ability of the EQ3/6 code and thermodynamic data base to describe mineral-fluid relations at elevated temperatures. Welfare starting long-term dissolution/corrosion tests of rocks, minerals and manufactured materials in natural thermal features in order to compare laboratory rates with field-derived rates. Available field data on rates of silica precipitation from heated fluids have been analyzed and compared to laboratory rates. New sets of precipitation experiments are being planned. The microbially influenced degradation of concrete in the Broadlands-Ohaaki geothermal field is being characterized. The authors will continue to work on these projects in FY 1996 and expand to include the study of naturally occurring uranium and thorium series radionuclides, as a prelude to studying radionuclide migration in heated silicic volcanic rocks. 32 refs.

  19. A Strategy for Interpretation of Microearthquake Tomography Results in the Salton Sea Geothermal Field Based upon Rock Physics Interpretations of State 2-14 Borehole Logs

    Energy Technology Data Exchange (ETDEWEB)

    Bonner, B; Hutchings, L; Kasameyer, P


    We devise a strategy for analysis of Vp and Vs microearthquake tomography results in the Salton Sea geothermal field to identify important features of the geothermal reservoir. We first interpret rock properties in State 2-14 borehole based upon logged core through the reservoir. Then, we interpret seismic recordings in the well (Daley et al., 1988) to develop the strategy. We hypothesize that mapping Poisson's ratio has two applications for the Salton Sea geothermal reservoir: (1) to map the top of the reservoir, and (2) as a diagnostic for permeable zones. Poisson's ratio can be obtained from Vp and Vs. In the State 2-14 borehole, Poisson's ratio calculated from large scale averages ({approx} 150 m) shows a monotonic decrease with depth to about 1300 m, at which point it increases with depth. Our model is that the monotonic decrease is due to compaction, and the increase below 1300 m is due to the rocks being hydrothermally altered. We hypothesize we can map the depth to alteration by identifying the transition from decreasing to increasing values; and thus, map the top of the reservoir, which is associated with a known increase in sulfite, chlorite, and epidote alteration that may be indicative of hydrothermal activity. We also observe (from Daley et. al. plots) an anomalous drop in Poisson's ratio at a depth of about 900 m, within a sandstone formation. The sandstone has a P-wave velocity significantly higher than the siltstone above it but a lower velocity in the lower half of the formation relative to the upper half. We interpret the relative decrease in velocity to be due to fracturing and chemical alteration caused by permeability. We conclude that using Vp and Vs tomography results to obtain images of Poisson's ratio has the potential to identify significant features in the geothermal reservoir in this geologic setting. Seismic attenuation tomography results (mapped as Qp and Qs) should also be useful for evaluating geothermal

  20. Overview for geologic field-trip guides to volcanoes of the Cascades Arc in northern California (United States)

    Muffler, L. J. Patrick; Donnelly-Nolan, Julie M.; Grove, Timothy L.; Clynne, Michael A.; Christiansen, Robert L.; Calvert, Andrew T.; Ryan-Davis, Juliet


    The California Cascades field trip is a loop beginning and ending in Portland, Oregon. The route of day 1 goes eastward across the Cascades just south of Mount Hood, travels south along the east side of the Cascades for an overview of the central Oregon volcanoes (including Three Sisters and Newberry Volcano), and ends at Klamath Falls, Oregon. Day 2 and much of day 3 focus on Medicine Lake Volcano. The latter part of day 3 consists of a drive south across the Pit River into the Hat Creek Valley and then clockwise around Lassen Volcanic Center to the town of Chester, California. Day 4 goes from south to north across Lassen Volcanic Center, ending at Burney, California. Day 5 and the first part of day 6 follow a clockwise route around Mount Shasta. The trip returns to Portland on the latter part of day 6, west of the Cascades through the Klamath Mountains and the Willamette Valley. Each of the three sections of this guidebook addresses one of the major volcanic regions: Lassen Volcanic Center (a volcanic field that spans the volcanic arc), Mount Shasta (a fore-arc stratocone), and Medicine Lake Volcano (a rear-arc, shield-shaped edifice). Each section of the guide provides (1) an overview of the extensive field and laboratory studies, (2) an introduction to the literature, and (3) directions to the most important and accessible field localities. The field-trip sections contain far more stops than can possibly be visited in the actual 6-day 2017 IAVCEI excursion from Portland. We have included extra stops in order to provide a field-trip guide that will have lasting utility for those who may have more time or may want to emphasize one particular volcanic area.

  1. Geothermal Information Dissemination and Outreach

    Energy Technology Data Exchange (ETDEWEB)

    Clutter, Ted J. [Geothermal Resources Council (United States)


    Project Purpose. To enhance technological and topical information transfer in support of industry and government efforts to increase geothermal energy use in the United States (power production, direct use, and geothermal groundsource heat pumps). Project Work. GRC 2003 Annual Meeting. The GRC convened the meeting on Oct. 12-15, 2003, at Morelia's Centro de Convenciones y ExpoCentro in Mexico under the theme, International Collaboration for Geothermal Energy in the Americas. The event was also sponsored by the Comision Federal de Electricidad. ~600 participants from more than 20 countries attended the event. The GRC convened a Development of Geothermal Projects Workshop and Geothermal Exploration Techniques Workshop. GRC Field Trips included Los Azufres and Paricutin Volcano on Oct. 11. The Geothermal Energy Association (Washington, DC) staged its Geothermal Energy Trade Show. The Annual Meeting Opening Session was convened on Oct. 13, and included the governor of Michoacan, the Mexico Assistant Secretary of Energy, CFE Geothermal Division Director, DOE Geothermal Program Manager, and private sector representatives. The 2003 Annual Meeting attracted 160 papers for oral and poster presentations. GRC 2004. Under the theme, Geothermal - The Reliable Renewable, the GRC 2004 Annual Meeting convened on Aug. 29-Sept. 1, 2004, at the Hyatt Grand Champions Resort at Indian Wells, CA. Estimated total attendance (including Trade Show personnel, guests and accompanying persons) was ~700. The event included a workshop, Geothermal Production Well Pump Installation, Operation and Maintenance. Field trips went to Coso/Mammoth and Imperial Valley/Salton Sea geothermal fields. The event Opening Session featured speakers from the U.S. Department of Energy, U.S. Department of the Interior, and the private sector. The Geothermal Energy Association staged its Geothermal Energy Trade Show. The Geothermal Education Office staged its Geothermal Energy Workshop. Several local radio and

  2. Geothermal Permeability Enhancement - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Joe Beall; Mark Walters


    The overall objective is to apply known permeability enhancement techniques to reduce the number of wells needed and demonstrate the applicability of the techniques to other undeveloped or under-developed fields. The Enhanced Geothermal System (EGS) concept presented in this project enhances energy extraction from reduced permeability zones in the super-heated, vapor-dominated Aidlin Field of the The Geysers geothermal reservoir. Numerous geothermal reservoirs worldwide, over a wide temperature range, contain zones of low permeability which limit the development potential and the efficient recovery of heat from these reservoirs. Low permeability results from poorly connected fractures or the lack of fractures. The Enhanced Geothermal System concept presented here expands these technologies by applying and evaluating them in a systematic, integrated program.

  3. Geothermal energy

    Directory of Open Access Journals (Sweden)

    Manzella A.


    Full Text Available Geothermal technologies use renewable energy resources to generate electricity and direct use of heat while producing very low levels of greenhouse-gas (GHG emissions. Geothermal energy is stored in rocks and in fluids circulating in the underground. Electricity generation usually requires geothermal resources temperatures of over 100°C. For heating, geothermal resources spanning a wider range of temperatures can be used in applications such as space and district heating (and cooling, with proper technology, spa and swimming pool heating, greenhouse and soil heating, aquaculture pond heating, industrial process heating and snow melting. Geothermal technology, which has focused so far on extracting naturally heated steam or hot water from natural hydrothermal reservoirs, is developing to more advanced techniques to exploit the heat also where underground fluids are scarce and to use the Earth as a potential energy battery, by storing heat. The success of the research will enable energy recovery and utilization from a much larger fraction of the accessible thermal energy in the Earth’s crust.

  4. Phase 1 Feasibility Study, Canby Cascaded Geothermal Project, April 2, 2013

    Energy Technology Data Exchange (ETDEWEB)

    Merrick, Dale E [CanbyGeo, LLC


    A small community in Northern California is attempting to use a local geothermal resource to generate electrical power and cascade residual energy to an existing geothermal district heating system, greenhouse, and future fish farm and subsequent reinjection into the geothermal aquifer, creating a net-zero energy community, not including transportation.

  5. Estimation and monitoring heat discharge rates using Landsat ETM+ thermal infrared data: a case study in Unzen geothermal field, Kyushu, Japan (United States)

    Mia, Md. B.; Fujimitsu, Yasuhiro; Bromely, Chris J.


    The Unzen geothermal field, our study area is active fumaroles, situated in Shimabara Peninsula of Kyushu Island in Japan. Our prime objectives were (1) to estimate radiative heat flux (RHF), (2) to calculate approximately heat discharge rate (HDR) using the relationship of radiative heat flux with the total heat loss derived from two geothermal field studies and (3) finally, to monitor RHF as well as HDR in our study area using seven sets of Landsat 7 ETM+ images from 2000 to 2009. We used the NDVI (Normalized differential vegetation index) method for spectral emissivity estimation, the mono-window algorithm for land surface temperature (LST) and the Stefan-Boltzmann equation analyzing those satellite TIR images for RHF. We obtained a desired strong correlation of LST above ambient with RHF using random samples. We estimated that the maximum RHF was about 251 W/m2 in 2005 and minimum was about 27 W/m2 in 2001. The highest total RHF was about 39.1 MW in 2005 and lowest was about 12 MW in 2001 in our study region. We discovered that the estimated RHF was about 15.7 % of HDR from our studies. We applied this percentage to estimate heat discharge rate in Unzen geothermal area. The monitoring results showed a single fold trend of HDR from 2000 to 2009 with highest about 252 MW in 2005 and lowest about 78 MW in 2001. In conclusion, TIR remote sensing is thought as the best option for monitoring heat losses from fumaroles with high efficiency and low cost.

  6. University of California, San Diego (UCSD) Sky Imager Cloud Position Study Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Kleissl, J. [Univ. of California, San Diego, CA (United States); Urquhart, B. [Univ. of California, San Diego, CA (United States); Ghonima, M. [Univ. of California, San Diego, CA (United States); Dahlin, E. [Univ. of California, San Diego, CA (United States); Nguyen, A. [Univ. of California, San Diego, CA (United States); Kurtz, B. [Univ. of California, San Diego, CA (United States); Chow, C. W. [Univ. of California, San Diego, CA (United States); Mejia, F. A. [Univ. of California, San Diego, CA (United States)


    During the University of California, San Diego (UCSD) Sky Imager Cloud Position Study, two University of California, San Diego Sky Imagers (USI) (Figure 1) were deployed the U.S. Department of Energy(DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains SGP) research facility. The UCSD Sky Imagers were placed 1.7 km apart to allow for stereographic determination of the cloud height for clouds over approximately 1.5 km. Images with a 180-degree field of view were captured from both systems during daylight hours every 30 seconds beginning on March 11, 2013 and ending on November 4, 2013. The spatial resolution of the images was 1,748 × 1,748, and the intensity resolution was 16 bits using a high-dynamic-range capture process. The cameras use a fisheye lens, so the images are distorted following an equisolid angle projection.

  7. Geothermal initiatives in Central America

    Energy Technology Data Exchange (ETDEWEB)

    Hanold, R.J.; Loose, V.W.; Laughlin, A.W.; Wade, P.E.


    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.

  8. Uncertainty analysis of geothermal energy economics (United States)

    Sener, Adil Caner

    This dissertation research endeavors to explore geothermal energy economics by assessing and quantifying the uncertainties associated with the nature of geothermal energy and energy investments overall. The study introduces a stochastic geothermal cost model and a valuation approach for different geothermal power plant development scenarios. The Monte Carlo simulation technique is employed to obtain probability distributions of geothermal energy development costs and project net present values. In the study a stochastic cost model with incorporated dependence structure is defined and compared with the model where random variables are modeled as independent inputs. One of the goals of the study is to attempt to shed light on the long-standing modeling problem of dependence modeling between random input variables. The dependence between random input variables will be modeled by employing the method of copulas. The study focuses on four main types of geothermal power generation technologies and introduces a stochastic levelized cost model for each technology. Moreover, we also compare the levelized costs of natural gas combined cycle and coal-fired power plants with geothermal power plants. The input data used in the model relies on the cost data recently reported by government agencies and non-profit organizations, such as the Department of Energy, National Laboratories, California Energy Commission and Geothermal Energy Association. The second part of the study introduces the stochastic discounted cash flow valuation model for the geothermal technologies analyzed in the first phase. In this phase of the study, the Integrated Planning Model (IPM) software was used to forecast the revenue streams of geothermal assets under different price and regulation scenarios. These results are then combined to create a stochastic revenue forecast of the power plants. The uncertainties in gas prices and environmental regulations will be modeled and their potential impacts will be

  9. Areas to explore surrounding the Cerro Prieto geothermal field, BC; Areas para exploracion en los alrededores del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar Dumas, Alvaro [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail:


    Exploration plays an important role in tapping underground natural resources-whether water, oil, natural gas or minerals. Exploratory data allow us to learn reservoir conditions, increasing probable reserves and reservoir life span. Around the Cerro Prieto geothermal field, BC, and in the Mexicali Valley in general, exploration had almost stopped but recently was resumed by the Studies Division of Comision Federal de ELectricidad (CFE)'s Gerencia de Proyectos Geotermoelectricos. The division sent technical personnel to structurally map the northern and eastern portions of Laguna Salada. The paper offers a general outline of the main zones undergoing exploratory studies-studies perhaps culminating in siting exploratory wells to locate more geothermal resources (and ultimately producing them using binary power plants). CFE also wants to site injection wells west of the current production zone, and this is covered, as well. All activities are meant to increase the productive lifespan of the geothermal reservoir. [Spanish] Cuando se trata de la explotacion de recursos naturales del subsuelo, sea agua, gas, petroleo o minerales, la exploracion juega un papel muy importante, ya que permite conocer las condiciones del yacimiento que pudieran llevar a incrementar las reservas de los recursos explotados y extender su vida util. En las zonas aledanas al campo geotermico de Cerro Prieto, BC, y en general en el Valle de Mexicali, la exploracion estaba practicamente detenida habiendose reactivado a raiz de que la Subgerencia de Estudios de la Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad (CFE) envio personal para realizar mapeos estructurales en las porciones norte y oriente de la Laguna Salada. Este trabajo presenta un panorama general de las areas prioritarias para realizar estudios exploratorios y poder programar, con mas bases, pozos exploratorios enfocados a localizar mas recursos geotermicos, inclusive para generar energia por medio

  10. Economic, environmental and social impacts of geothermal development, and energy savings and efficient use of power in Baja California, Mexico; Impactos economicos, ambientales y sociales del desarrollo geotermico y del ahorro y uso eficiente de la electricidad en Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Campbell R, Hector E.; Montero A, Gisela [Universidad Autonoma de Baja California, Instituto de Ingenieria, Mexicali, Baja California (Mexico)]. E-mail:; Lambert A., Alejandro A. [Universidad Autonoma de Baja California, Facultad de Ingenieria, Mexicali, Baja California (Mexico)


    This essay of electrical planning for Baja California, Mexico, includes diagnosis of power production and consumption from 1994-2005, prospective to 2025 if historical trends are maintained, discussion of a systemic plan and its impact on the prospective through energy savings and energy efficient use, combined with an increase of the geothermal energy share. Diagnosis indicates that geothermal capacity in 1998 accounted for 57% of total electric capacity in Baja California, and by 2004 73% of this total electric capacity was based on natural gas, increasing energy dependence on fossil fuels. During this period, electric generation changed from a ratio of 2 to 1 (geothermal steam to fuel oil) to 1 to 1 (geothermal steam to natural gas). The unit cost of natural gas energy with an efficiency of 50% is 24 times the cost of the same unit of geothermal steam with 16% efficiency. Power generation, with fuel oil or simple cycle turbines firing natural gas, costs twice that of combined cycle turbines, while the costs are three times less with geothermal steam. In 2005, as a consequence of a minor contribution of geothermal energy to the power-generation total, production costs increased, reaching $122.80 USD/MWh. The replacement of fuel oil, as power fuel, decreased the SO{sub x} emissions from 4.16 kg/MWh to 0.19 kg/MWh. The combined-cycle fired by natural gas diminished the relative emissions of NO{sub x} and CO{sub 2} by 30%, but the 2.6 million tons of CO{sub x} given off each year did no vary significantly. Using geothermal energy avoids burning 20 million barrels of oil equivalent annually. The Prospective 2005-2025 indicates Baja California requires the installation of an additional 4500 MW to reach 7200 MW. The energy portfolio will become more dependent on natural gas increasing its share from 60% to 86%. Geothermal energy will decrease its share in installed capacity to 10%, eliminating the damping effect on the cost of production. SO{sub x} emissions will

  11. Proceedings of NEDO International Geothermal Symposium

    Energy Technology Data Exchange (ETDEWEB)



    This is a proceedings of the NEDO International Geothermal Symposium held in Sendai in 1997. The worldwide geothermal energy power generation capacity exceeds 7000 MW. Geothermal energy is widely used also for heating, snow melting, greenhouse cultivation as well as electric power generation. Geothermal energy generates far less CO2 causing the global warming than fossil fuels. The geothermal energy is clean and renewable. Considering the environmental issue and energy supply/demand of the world, we have to exert further efforts for the geothermal development. In this conference, discussions were made on each country`s experiences of the geothermal development, and future prediction and strategies for geothermal utilization in the Asia/Pacific region, in particular. Further, in the technical session, conducted were the IEA study and technical presentation/discussion for technical cooperation. The proceedings includes research reports of more than 30, which are clarified into three fields: impacts of the geothermal development on the environment, technical development of the hot dry rock power generation system, and development of technology for collecting deep-seated geothermal resource

  12. Geothermal Technologies Program: Utah

    Energy Technology Data Exchange (ETDEWEB)


    Geothermal Technologies Program Utah fact sheet describes the geothermal areas and use in Utah, focusing on power generation as well as direct use, including geothermally heated greenhouses, swimming pools, and therapeutic baths.

  13. Geothermal tomorrow 2008

    Energy Technology Data Exchange (ETDEWEB)

    None, None


    Contributors from the Geothermal Technologies Program and the geothermal community highlight the current status and activities of the Program and the development of the global resource of geothermal energy.

  14. Worldwide Geothermal Power Plants: Status as of June 1980

    Energy Technology Data Exchange (ETDEWEB)

    DiPippo, Ronald


    There are 100 geothermal power units now in operation throughout 12 countries, with a total installed capacity of just over 2110 MW. The average unit thus is rated at 21.1 MW. Newer units may be broadly classified as follows: (a) wellhead units of less than 5 MW; (b) small plants of about 10 MW; (c) medium plants of 30-35 MW; (d) large plants of about 55 MW; and (e) complexes typically consisting of several 55 MW units in a large geothermal field. There is a trend toward turbine units of the double-flow type with a 55 MW rating, used either alone or in a tandem-compound arrangement giving 110 MW in a single power house. This is particularly evident at The Geysers field in California. Double-flash units (separated-steam followed by a surface flash) are suited to high quality reservoirs having high temperature, high steam fractions at the wellhead, and low scaling potential. Single-flash units (separated steam) may be called for where scaling by the spent brine is a potential problem for the liquid disposal system. Binary plants are being used for some very low temperature reservoirs, particularly in the People's Republic of China, albeit in extremely small units. A large-scale pilot plant of the binary type is being planned for the Imperial Valley of California.

  15. The National Geothermal Energy Research Program (United States)

    Green, R. J.


    The continuous demand for energy and the concern for shortages of conventional energy resources have spurred the nation to consider alternate energy resources, such as geothermal. Although significant growth in the one natural steam field located in the United States has occurred, a major effort is now needed if geothermal energy, in its several forms, is to contribute to the nation's energy supplies. From the early informal efforts of an Interagency Panel for Geothermal Energy Research, a 5-year Federal program has evolved whose objective is the rapid development of a commercial industry for the utilization of geothermal resources for electric power production and other products. The Federal program seeks to evaluate the realistic potential of geothermal energy, to support the necessary research and technology needed to demonstrate the economic and environmental feasibility of the several types of geothermal resources, and to address the legal and institutional problems concerned in the stimulation and regulation of this new industry.

  16. Magnetotelluric Investigation of Structures Related to a Geothermal Anomaly in the Buckman Well field in the Rio Grande Rift, New Mexico (United States)

    Jones, D.; Chu, S.; McCormack, K.; Barghouty, L. K.; Mostafanejad, A.; Lasscock, B.; Bedrosian, P.; Pellerin, L.


    High borehole temperature gradients have been measured over short spatial scales in the Buckman Well Field located within the Espanola Basin of the Rio Grande Rift, New Mexico. The proximity of the well field to the young Caja del Rio volcanic plateau prompted a study undertaken by the Summer of Applied Geophysical Experience (SAGE) program to uncover structure related to this geothermal anomaly. The localized nature of this geothermal anomaly is suggested to be indicative of a local controlling structure as opposed to a more regional structure. Two-dimensional (2-D) models were constructed using magnetotelluric (MT) and audiomagnetotelluric (AMT) data acquired during 2011-13 seasons of the SAGE field program. Geoelectric strike, being important in determining whether an optimal survey design was employed for 2-D MT inverse modeling, was determined from Swift';s formula, which is subject to galvanic distortion. The geoelectric strike direction obtained from a phase tensor analysis, unaffected by such distortion, generally agreed with the established geological strike of the region. The phase tensor analysis shows predominantly 2-D behavior, although some three-dimensional (3-D) character is observed in the low-frequency MT data. An independent statistical metric developed at SAGE confirms these findings. This observation could be reflected as a conductive anomaly found in the 2-D MT inverse model. Synthetic data were generated to test the sensitivity of the 2-D inversion method to different layer resistivity values and faulted structures in the AMT range. Using these synthetic results to understand the inversion of field data we identify conductive horizons at 100 m and 250-300 m depth. The MT models estimate basin depth at 3-4 km in accordance with independent constraints from geologic mapping, gravity models and seismic imaging. Variations in basement topography correlate to some degree with previously proposed structural features elsewhere beneath the Caja del

  17. Lichens as biological monitors in the Los Azufres geothermal field, Michoacan, Mexico; Liquenes como indicadores biologicos en el campo geotermico Los Azufres, Michoacan, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Peralta, Marlene; Chavez Carmona, Arturo [Universidad Michoacana de San Nicolas de Hidalgo, Morelia (Mexico)


    The results obtained in the monitoring of the atmospheric emissions of the Los Azufres geothermal field in Michoacan State, Mexico utilizing lichens as monitors of the presence of sulphur and arsenic, at the areas near geothermal sites, both under evaluation and production, are presented. The results are based on symptoms which included: chlorosis, necrosis, brown and reddish spots, loss of adherence to substrate, thalli disintegration and disappearance of sensitive species; and also on the amounts of sulphur and arsenic contained in the lichens thallus. [Espanol] Se presentan los resultados obtenidos en el monitoreo de las emisiones atmosfericas del campo geotermico Los Azufres, Michoacan, Mexico en el que se utilizaron liquenes como indicadores de la presencia de azufre y arsenico, en las areas cercanas a los sitios de pozos geotermicos tanto en evaluacion como en produccion. Los resultados estan basados en sintomas que incluyen clorosis, necrosis, manchas cafes y rojizas, perdida de adherencia al sustrato, desintegracion del talo y desaparicion de especies sensibles; asi como en los contenidos de azufre y arsenico en los talos liquenicos.

  18. The 2010 California Research at the Nexus of Air Quality and Climate Change (CalNex) field study


    Ryerson, T. B.; Flagan, R. C.; J. H. Seinfeld


    The California Research at the Nexus of Air Quality and Climate Change (CalNex) field study was conducted throughout California in May, June, and July of 2010. The study was organized to address issues simultaneously relevant to atmospheric pollution and climate change, including (1) emission inventory assessment, (2) atmospheric transport and dispersion, (3) atmospheric chemical processing, and (4) cloud-aerosol interactions and aerosol radiative effects. Measurements from networks of ground...

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

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, S.C.


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

  20. Stanford geothermal program. Final report, July 1990--June 1996

    Energy Technology Data Exchange (ETDEWEB)



    This report discusses the following: (1) improving models of vapor-dominated geothermal fields: the effects of adsorption; (2) adsorption characteristics of rocks from vapor-dominated geothermal reservoir at the Geysers, CA; (3) optimizing reinjection strategy at Palinpinon, Philippines based on chloride data; (4) optimization of water injection into vapor-dominated geothermal reservoirs; and (5) steam-water relative permeability.

  1. Understanding the Geodynamic Role of Structural Elements and their Influence on (Paleo)Fluid Flow at the Licancura Geothermal Field, northern Chile (United States)

    Aron, F.; Veloso, E. E.; Camus, E.; Morata, D.; Arancibia, G.; Del Valle, F.; Cembrano, J. M.


    The southern part of the Central Andean Volcanic Zone, undergoing compression arising from the plate convergence, hosts a series of potential geothermal fields. Regional surveys suggest a genetic link between arc-parallel and arc-oblique structural elements (e.g. cataclasites, hydrothermal breccia, fault veins and veins) and mineral alteration patterns. Remote sensing analyses of the Licancura-Camiña area show a strong mineral alteration pattern, most probably resulting from an increased heat and fluid flow. We carried a detailed field survey and log the orientation, kinematics and associated mineral species for a variety of structural elements, aiming to stablish a relation between types of structural elements, stress fields, and mineral occurrences in the development of a geothermal field. In the field at Licancura, NW- and NNE-to-NE-striking structural elements display right- and left-lateral, and thrust displacements as they cut Miocene-Pliocene(?) volcaniclastic rocks. Structural elements show evidence of fluid emplacement as particular hydrothermal mineral assemblages (i.e. epidote) are part of the matrix or the filling material. Estimation of stress fields indicates three different regimes. The obtained strike-slip transpressional solution likely represents the accommodation of the shear component of the far-stress field imposed by the plate convergence. Reverse stress field solutions indicate NE- and NNW-trending compression and subvertical tension, likely due to plate convergence and local accommodation, respectively. The common NE-trending orientation of the s1 axis for the strike-slip and one of the reverse stress field solutions argues that some NW-striking thrust faults may be reactivated former strike-slip faults. Multiple statistical clustering of the poles to veins is consistent with orientation clusters defined by mineral associations. Estimations of the orientation of the s3 axes from vein clusters are consistent with those obtained from shear

  2. Federal Geothermal Research Program Update - Fiscal Year 2004

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Laney


    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

  3. Federal Geothermal Research Program Update Fiscal Year 2004

    Energy Technology Data Exchange (ETDEWEB)


    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

  4. Fifteenth workshop on geothermal reservoir engineering: Proceedings

    Energy Technology Data Exchange (ETDEWEB)


    The Fifteenth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 23--25, 1990. Major topics included: DOE's geothermal research and development program, well testing, field studies, geosciences, geysers, reinjection, tracers, geochemistry, and modeling.

  5. Tracking federal land management: Report No. 3 on federal land management actions impacting geothermal commecialization at selected target prospects in the five Pacific Rim states

    Energy Technology Data Exchange (ETDEWEB)


    Generic land management actions affecting geothermal commerializtion in Pacific River states are reviewed. Specific federal land management actions affecting geothermal prospects in California and the Pacific Northwest are described. (MHR)

  6. Long-term monitoring of ULF electromagnetic fields at Parkfield, California (United States)

    Kappler, K. N.; Morrison, H. Frank; Egbert, G. D.


    Electric and magnetic fields in the (10-4-1.0) Hz band were monitored at two sites adjacent to the San Andreas Fault near Parkfield and Hollister, California, from 1995 to 2007. A data window (2002-2005), enclosing the 28 September 2004 M6 Parkfield earthquake, was analyzed to determine if anomalous electric or magnetic fields or changes in ground conductivity occurred before the earthquake. The data were edited, removing intervals of instrument malfunction, leaving 875 days in the 4 year period. Frequent, spikelike disturbances were common but were not more frequent around the time of the earthquake; these were removed before subsequent processing. Signal-to-noise amplitude spectra, estimated via magnetotelluric processing, showed the behavior of the ultralow frequency fields to be remarkably constant over the period of analysis. These first-order plots make clear that most of the recorded energy is coherent over the spatial extent of the array. Three main statistical techniques were employed to separate local anomalous electrical or magnetic fields from the dominant coherent natural fields: transfer function estimates between components at each site were employed to subtract the dominant field, and look deeper at the "residual" fields; the data were decomposed into principal components to identify the dominant coherent array modes; and the technique of canonical coherences was employed to distinguish anomalous fields which are spatially broad from anomalies which occur at a single site only, and furthermore to distinguish anomalies present in both the electric and magnetic fields from those present in only one field type. Standard remote reference apparent resistivity estimates were generated daily at Parkfield. A significant seasonal component of variability was observed, suggesting local distortion due to variations in near-surface resistance. In all cases, high levels of sensitivity to subtle electromagnetic effects were demonstrated, but no effects were found

  7. A preliminary interpretation of gas composition in the CP IV sector wells, Cerro Prieto geothermal field, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Barragan Reyes, Rosa Maria; Arellano Gomez, Victor M; Portugal Marin, Enrique [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Morelos (Mexico)]. E-mail:; Perez Hernandez, Alfredo; Rodriguez Rodriguez, Marco Helio; Leon Vivar, Jesus de [Comision Federal de Electricidad, Residencia General Cerro Prieto, B.C. (Mexico)


    To increase the electrical generation capacity of the Cerro Prieto geothermal field from 620 MW to 720 MW, the Cerro Prieto IV (CP IV) sector of the field was developed in the NE portion of the exploited field. Fourteen new wells have been drilled there since 2000. The wells in CP IV zone produce two-phase fluids at wellhead with heterogeneous steam fraction characteristics: at the central zone and towards the NW, the wells are liquid-dominated while those towards the E and S produce a relatively high steam fraction. This work studies the gas compositions of produced fluids to obtain reservoir parameters such as temperature and steam fraction and identify different sources of fluids in the wells. A method was used based on the Fischer Tropsch reaction and H{sub 2}S equilibria with pyrite-pyrrhotite as a mineral buffer (FT-HSH3). The results for the natural state showed the presence of fluids with reservoir temperatures from 275 to 310 degrees Celsius and excess steam values from -1 to 50%. Data are aligned in a FT-HSH3 trend, suggesting that the well discharges consist of a mixture in different proportions of the two end members. One seems to be a liquid with a temperature of over 300 degrees Celsius with negative or negligible excess steam. The other seems to be a two-phase fluid with a temperature of about 275 degrees Celsius and an excess steam fraction of about 0.5. According to the data for single wells and depending on the production conditions of the wells, reservoir fluid mixtures could occur in different proportions of liquid and steam. Data for 2005 that included wells drilled after 2000 suggest the presence of a steam phase in the reservoir. The steam could be generated with the boiling of deep reservoir fluid from a pressure drop. The mixing trend obtained for the natural state was also seen for 2005 data but lower temperatures (from 265 to 295 degrees Celsius) were obtained compared with those for natural conditions. The entry of lower

  8. Energy and Exergy Analysis of Kalina Cycle for the Utilization of Waste Heat in Brine Water for Indonesian Geothermal Field

    Directory of Open Access Journals (Sweden)

    Nasruddin Nasruddin


    Full Text Available The utilization of waste heat in a power plant system—which would otherwise be released back to the environment—in order to produce additional power increases the efficiency of the system itself. The purpose of this study is to present an energy and exergy analysis of Kalina Cycle System (KCS 11, which is proposed to be utilized to generate additional electric power from the waste heat contained in geothermal brine water available in the Lahendong Geothermal power plant site in North Sulawesi, Indonesia. A modeling application on energy and exergy system is used to study the design of thermal system which uses KCS 11. To obtain the maximum power output and maximum efficiency, the system is optimized based on the mass fraction of working fluid (ammonia-water, as well as based on the turbine exhaust pressure. The result of the simulation is the optimum theoretical performance of KCS 11, which has the highest possible power output and efficiency. The energy flow diagram and exergy diagram (Grassman diagram was also presented for KCS 11 optimum system to give quantitative information regarding energy flow from the heat source to system components and the proportion of the exergy input dissipated in the various system components.

  9. Resistivity During Boiling in the SB-15-D Core from the Geysers Geothermal Field: The Effects of Capillarity

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, J.; Duba, A.; Bonner, B.; Kasameyer, P.


    In a laboratory study of cores from borehole SB-15-D in The Geysers geothermal area, we measured the electrical resistivity of metashale with and without pore-pressure control, with confining pressures up to 100 bars and temperatures between 20 and 150 C, to determine how the pore-size distribution and capillarity affected boiling. We observed a gradual increase in resistivity when the downstream pore pressure or confining pressure decreased below the phase boundary of free water. For the conditions of this experiment, boiling, as indicated by an increase in resistivity, is initiated at pore pressures of approximately 0.5 to 1 bar (0.05 to 0.1 MPa) below the free-water boiling curve, and it continues to increase gradually as pressure is lowered to atmospheric. A simple model of the effects of capillarity suggests that at 145 C, less than 15% of the pore water can boil in these rocks. If subsequent experiments bear out these preliminary observations, then boiling within a geothermal reservoir is controlled not just by pressure and temperature but also by pore-size distribution. Thus, it may be possible to determine reservoir characteristics by monitoring changes in electrical resistivity as reservoir conditions change.

  10. Stanford Geothermal Program

    Energy Technology Data Exchange (ETDEWEB)

    R. Horn


    Reliable measurement of steam-water relative permeability functions is of great importance for geothermal reservoir performance simulation. Despite their importance, these functions are poorly known due to the lack of fundamental understanding of steam-water flows, and the difficulty of making direct measurements. The Stanford Geothermal Program has used an X-ray CT (Computer Tomography) scanner to obtain accurate saturation profiles by direct measurement. During the last five years, the authors have carried out experiments with nitrogen-water flow and with steam-water flow, and examined the effects of heat transfer and phase change by comparing these sets of results. In porous rocks, it was found that the steam-water relative permeabilities follow Corey type relationships similar to those in nitrogen-water flow, but that the irreducible gas phase saturation is smaller for steam than for nitrogen. The irreducible saturations represent substantial fractions of the recoverable energy in place yet are hard to determine in the field. Understanding the typical magnitude of irreducible saturations will lead to a much clearer forecast of geothermal field performance. In fracture flow, indirect measurements suggested that the relative permeabilities follow a linear (or ''X-curve'') behavior - but there is still considerable uncertainty in the knowledge of this behavior.

  11. Crustal deformation and gravity changes during the first ten years of exploitation of the new Travale-Radicondoli geothermal field, Italy

    Energy Technology Data Exchange (ETDEWEB)

    Geri, G.; Marson, I.; Rossi, A.; Toro, B.


    The results of precise levelling measurements on a specially constructed network of benchmarks in the Travale geothermal area (Tuscany, Italy) revealed that the central part of this area is subsiding and that the average rate of subsidence in the period 1973-1983 was 20-25 mm/year. Three series of horizontal distance measurements were carried out (1980, 1981, 1982) to monitor variations in the coordinates of the bases of a horizontal control net. The variations noted in this time interval range between 13 and 36 mm, slightly exceeding the semi-axis values of their error ellipses. A series of gravity measurements was carried out annually between 1979 and 1982 on a network of gravity benchmarks coinciding with part of the topographic benchmarks. The g variations observed reached a maximum of 40 Gal. A tentative correlation of these data with field exploitation data indicates a possible means of interpreting the variations observed during these surveys.

  12. Rock specific hydraulic fracturing and matrix acidizing to enhance a geothermal system — Concepts and field results (United States)

    Zimmermann, Günter; Blöcher, Guido; Reinicke, Andreas; Brandt, Wulf


    Enhanced geothermal systems (EGS) are engineered reservoirs developed to extract economic amounts of heat from low permeability and/or porosity geothermal resources. To enhance the productivity of reservoirs, a site specific concept is necessary to actively make reservoir conditions profitable using specially adjusted stimulation treatments, such as multi fracture concepts and site specific well path design. The results of previously performed stimulation treatments in the geothermal research well GtGrSk4/05 at Groß Schönebeck, Germany are presented. The reservoir is located at a 4100-4300 m depth within the Lower Permian of the NE German Basin with a bottom-hole temperature of 150 °C. The reservoir rock is classified by two lithological units from bottom to top: volcanic rocks (andesitic rocks) and siliciclastics ranging from conglomerates to fine-grained sandstones (fluvial sediments). The stimulation treatments included multiple hydraulic stimulations and an acid treatment. In order to initiate a cross-flow from the sandstone layer, the hydraulic stimulations were performed in different depth sections (two in the sandstone section and one in the underlying volcanic section). In low permeability volcanic rocks, a cyclic hydraulic fracturing treatment was performed over 6 days in conjunction with adding quartz in low concentrations to maintain a sustainable fracture performance. Flow rates of up to 150 l/s were realized, and a total of 13,170 m 3 of water was injected. A hydraulic connection to the sandstone layer was successfully achieved in this way. However, monitoring of the water level in the offsetting well EGrSk3/90, which is 475 m apart at the final depth, showed a very rapid water level increase due to the stimulation treatment. This can be explained by a connected fault zone within the volcanic rocks. Two gel-proppant treatments were performed in the slightly higher permeability sandstones to obtain long-term access to the reservoir rocks. During each

  13. Orientation of minimum principal stress in the hot dry rock geothermal reservoir at Fenton Hill, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Burns, K.L.


    The stress field at the source of microearthquakes in the interior of the hot dry rock geothermal reservoir at Fenton Hill appears to be different to the far field stress outside the reservoir. The stress field seems to be re-oriented prior to failure, during the course of processes that inflate the reservoir. The state of stress, both inside and outside, the hot dry rock (HDR) geothermal reservoir at Fenton Hill, is important in predicting the course of stress-dependent processes, and in transferring HDR technology developed at Fenton Hill, to sites, such as at Clearlake in California, where the stress field is expected to be substantially different. The state of stress at Fenton Hill is not well known because of limitations in stress measuring technology. It is necessary to use a variety of indirect methods and seek an estimate of the stress. 5 refs.

  14. Remote sensing in the study of the perspective of enlargement of the geothermal area of Los Azufres field, Michoacan, Mexico; Utilizacion de la teledeteccion para estudiar las perspectivas de ampliacion de la zona geotermica de Los azufres, Michoacan, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Antaramian H, Eduardo; Garduno M, Victor Hugo [UMSNH, (Mexico)


    The results are presented of a remote sensing study in Los Azufres Geothermal field. Data of a volcanological study have been used. Standing out is the importance of a resurgence phenomenon in the volcanic evolution of the caldera of Los Azufres and its observed relationships with thermal anomalies outsides the area of well known geothermal resources in the field. On the basis of these data, we suggest additional remote sensing studies in different geothermal areas to identify blind resources or large thermal anomaly outsides the well know ones in developed geothermal fields. [Spanish] En este trabajo se presentan los resultados de un estudio de teledeteccion en la zona geotermica de Los Azufres, Michoacan, Mexico. En el se han utilizado los datos obtenidos de un estudio volcanologico que resalta la importancia de un fenomeno de resurgencia en la evolucion volcanologica de la Caldera de los Azufres y su relacion con anomalias termicas fuera de la zona de explotacion del campo geotermico. Con base en estos resultados se propone que sean retomados los datos de diferentes campos geotermicos con la finalidad de hacer estudios de exploracion mediante teledeteccion en campos ciegos o bien en aquellos ya desarrollados que presentan anomalias termicas mayores fuera de las ya conocidas.

  15. Estimating magnetic fields of homes near transmission lines in the California Power Line Study. (United States)

    Vergara, Ximena P; Kavet, Robert; Crespi, Catherine M; Hooper, Chris; Silva, J Michael; Kheifets, Leeka


    The California Power Line Study is a case-control study investigating the relation between residences near transmission lines and risk of childhood leukemia. It includes 5788 childhood leukemia cases and 5788 matched primary controls born between 1986 and 2007. We describe the methodology for estimating magnetic fields at study residences as well as for characterizing sources of uncertainty in these estimates. Birth residences of study subjects were geocoded and their distances to transmission lines were ascertained. 302 residences were deemed sufficiently close to transmission lines to have non-zero magnetic fields attributable to the lines. These residences were visited and detailed data, describing the physical configuration and dimensions of the lines contributing to the magnetic field at the residence, were collected. Phasing, loading, and directional load flow data for years of birth and diagnosis for each subject as well as for the day of site visit were obtained from utilities when available; when yearly average load for a particular year was not available, extrapolated values based on expert knowledge and prediction models were obtained. These data were used to estimate the magnetic fields at the center, closest and farthest point of each residence. We found good correlation between calculated fields and spot measurements of fields taken on site during visits. Our modeling strategies yielded similar calculated field estimates, and they were in high agreement with utility extrapolations. Phasing was known for over 90% of the lines. Important sources of uncertainty included a lack of information on the precise location of residences located within apartment buildings or other complexes. Our findings suggest that we were able to achieve high specificity in exposure assessment, which is essential for examining the association between distance to or magnetic fields from power lines and childhood leukemia risk. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Field investigation of duct system performance in California light commercial buildings

    Energy Technology Data Exchange (ETDEWEB)

    Delp, W.W.; Matson, N.E.; Tschudy, E. [and others


    This paper discusses field measurements of duct system performance in fifteen systems located in eight northern California buildings. Light commercial buildings, one- and two-story with package roof-top HVAC units, make up approximately 50% of the non-residential building stock in the U.S. Despite this fact little is known about the performance of these package roof-top units and their associated ductwork. These simple systems use similar duct materials and construction techniques as residential systems (which are known to be quite leaky). This paper discusses a study to characterize the buildings, quantify the duct leakage, and analyze the performance of the ductwork in these types of buildings. The study tested fifteen systems in eight different buildings located in northern California. All of these buildings had the ducts located in the cavity between the drop ceiling and the roof deck. In 50% of these buildings, this cavity was functionally outside the building`s air and thermal barriers. The effective leakage area of the ducts in this study was approximately 2.6 times that in residential buildings. This paper looks at the thermal analysis of the ducts, from the viewpoint of efficiency and thermal comfort. This includes the length of a cycle, and whether the fan is always on or if it cycles with the cooling equipment. 66% of the systems had frequent on cycles of less than 10 minutes, resulting in non-steady-state operation.

  17. Thermal-Economic Modularization of Small, Organic Rankine Cycle Power Plants for Mid-Enthalpy Geothermal Fields

    Directory of Open Access Journals (Sweden)

    Yodha Y. Nusiaputra


    Full Text Available The costs of the surface infrastructure in mid-enthalpy geothermal power systems, especially in remote areas, could be reduced by using small, modular Organic Rankine Cycle (ORC power plants. Thermal-economic criteria have been devised to standardize ORC plant dimensions for such applications. We designed a modular ORC to utilize various wellhead temperatures (120–170 °C, mass flow rates and ambient temperatures (−10–40 °C. A control strategy was developed using steady-state optimization, in order to maximize net power production at off-design conditions. Optimum component sizes were determined using specific investment cost (SIC minimization and mean cashflow (MCF maximization for three different climate scenarios. Minimizing SIC did not yield significant benefits, but MCF proved to be a much better optimization function.

  18. Alaska geothermal bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Liss, S.A.; Motyka, R.J.; Nye, C.J. (comps.)


    The Alaska geothermal bibliography lists all publications, through 1986, that discuss any facet of geothermal energy in Alaska. In addition, selected publications about geology, geophysics, hydrology, volcanology, etc., which discuss areas where geothermal resources are located are included, though the geothermal resource itself may not be mentioned. The bibliography contains 748 entries.

  19. Evidence for tectonic, lithologic, and thermal controls on fracture system geometries in an andesitic high-temperature geothermal field (United States)

    Massiot, Cécile; Nicol, Andrew; McNamara, David D.; Townend, John


    Analysis of fracture orientation, spacing, and thickness from acoustic borehole televiewer (BHTV) logs and cores in the andesite-hosted Rotokawa geothermal reservoir (New Zealand) highlights potential controls on the geometry of the fracture system. Cluster analysis of fracture orientations indicates four fracture sets. Probability distributions of fracture spacing and thickness measured on BHTV logs are estimated for each fracture set, using maximum likelihood estimations applied to truncated size distributions to account for sampling bias. Fracture spacing is dominantly lognormal, though two subordinate fracture sets have a power law spacing. This difference in spacing distributions may reflect the influence of the andesitic sequence stratification (lognormal) and tectonic faults (power law). Fracture thicknesses of 9-30 mm observed in BHTV logs, and 1-3 mm in cores, are interpreted to follow a power law. Fractures in thin sections (˜5 μm thick) do not fit this power law distribution, which, together with their orientation, reflect a change of controls on fracture thickness from uniform (such as thermal) controls at thin section scale to anisotropic (tectonic) at core and BHTV scales of observation. However, the ˜5% volumetric percentage of fractures within the rock at all three scales suggests a self-similar behavior in 3-D. Power law thickness distributions potentially associated with power law fluid flow rates, and increased connectivity where fracture sets intersect, may cause the large permeability variations that occur at hundred meter scales in the reservoir. The described fracture geometries can be incorporated into fracture and flow models to explore the roles of fracture connectivity, stress, and mineral precipitation/dissolution on permeability in such andesite-hosted geothermal systems.

  20. Determinants of field edge habitat restoration on farms in California's Sacramento Valley. (United States)

    Garbach, Kelly; Long, Rachael Freeman


    Degradation and loss of biodiversity and ecosystem services pose major challenges in simplified agricultural landscapes. Consequently, best management practices to create or restore habitat areas on field edges and other marginal areas have received a great deal of recent attention and policy support. Despite this, remarkably little is known about how landholders (farmers and landowners) learn about field edge management practices and which factors facilitate, or hinder, adoption of field edge plantings. We surveyed 109 landholders in California's Sacramento Valley to determine drivers of adoption of field edge plantings. The results show the important influence of landholders' communication networks, which included two key roles: agencies that provide technical support and fellow landholders. The networks of landholders that adopted field edge plantings included both fellow landholders and agencies, whereas networks of non-adopters included either landholders or agencies. This pattern documents that social learning through peer-to-peer information exchange can serve as a complementary and reinforcing pathway with technical learning that is stimulated by traditional outreach and extension programs. Landholder experience with benefits and concerns associated with field edge plantings were also significant predictors of adoption. Our results suggest that technical learning, stimulated by outreach and extension, may provide critical and necessary support for broad-scale adoption of field-edge plantings, but that this alone may not be sufficient. Instead, outreach and extension efforts may need to be strategically expanded to incorporate peer-to-peer communication, which can provide critical information on benefits and concerns. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Regional volcanic and structural study of Los Humeros, Puebla, Mexico geothermal field; Estudio regional volcanico y estructural del campo geotermico de Los Humeros, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Hernandez, Aida [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)


    A regional volcanic and structural study focused to know the principal deformation phases and their effects in the reservoir rocks was conducted around the Los Humeros geothermal zone in Puebla, Mexico. Four stages of deformations were recognized. The oldest phase had a compressional character and acted in late Cretaceous. During Miocene and Pliocene two extensional phases affected the lithologic sequence. The youngest stage was produced by vertical deformation associated with the magmatic and hydrothermal activity of this Quaternary volcanic center. In the geothermal field zone, the fluid movements are limited by the low permeability. Although the last local deformation phase, which is probably still active, generated a reduced sector of relatively high permeability. [Espanol] Se presentan los resultados de un estudio estructural y volcanico regional que incluye la Caldera de Los Humeros, Puebla, Mexico realizado con el proposito de determinar las diferentes etapas de deformacion que la afectan, su origen, y los efectos causados en las unidades litologicas. Los resultados indican la presencia de 4 etapas de deformacion. La mas antigua, de fines del Cretacico, fue compresional y afecto la secuencia sedimentaria jurasico-cretacica. Posteriormente, en las rocas del Mioceno y Plioceno se identificaron dos etapas de deformacion regional de tipo extensional. La cuarta etapa fue de caracter local, afecto al centro volcanido de Los Humeros y se debe al empuje principalmente vertical, a sociado a fenomenos magnaticos e hidrotermales que acompanaron la actividad eruptiva de este centro. En la zona del campo geotermico el movimiento de fluidos es muy reducido debido a la baja permeabilidad global de las rocas donde se aloja el yacimiento. Sin embargo, la ultima etapa de deformacion local, que aun es activa, produjo un ligero incremento de la permeabilidad en zonas preferenciales, que actualmente controlan el movimiento de los fluidos.

  2. Rocky 7 prototype Mars rover field geology experiments 1. Lavic Lake and sunshine volcanic field, California (United States)

    Arvidson, R. E.; Acton, C.; Blaney, D.; Bowman, J.; Kim, S.; Klingelhofer, G.; Marshall, J.; Niebur, C.; Plescia, J.; Saunders, R.S.; Ulmer, C.T.


    Experiments with the Rocky 7 rover were performed in the Mojave Desert to better understand how to conduct rover-based, long-distance (kilometers) geological traverses on Mars. The rover was equipped with stereo imaging systems for remote sensing science and hazard avoidance and 57Fe Mo??ssbauer and nuclear magnetic resonance spectrometers for in situ determination of mineralogy of unprepared rock and soil surfaces. Laboratory data were also obtained using the spectrometers and an X ray diffraction (XRD)/XRF instrument for unprepared samples collected from the rover sites. Simulated orbital and descent image data assembled for the test sites were found to be critical for assessing the geologic setting, formulating hypotheses to be tested with rover observations, planning traverses, locating the rover, and providing a regional context for interpretation of rover-based observations. Analyses of remote sensing and in situ observations acquired by the rover confirmed inferences made from orbital and simulated descent images that the Sunshine Volcanic Field is composed of basalt flows. Rover data confirmed the idea that Lavic Lake is a recharge playa and that an alluvial fan composed of sediments with felsic compositions has prograded onto the playa. Rover-based discoveries include the inference that the basalt flows are mantled with aeolian sediment and covered with a dense pavement of varnished basalt cobbles. Results demonstrate that the combination of rover remote sensing and in situ analytical observations will significantly increase our understanding of Mars and provide key connecting links between orbital and descent data and analyses of returned samples. Copyright 1998 by the American Geophysical Union.

  3. Geoelectrical structure by electrical logs and Schlumberger sounding at the Akinomiya geothermal field, Akita Prefecture; Denki kenso oyobi Schlumberger ho ni yoru Akinomiya chinetsu chiiki no hiteiko kozo

    Energy Technology Data Exchange (ETDEWEB)

    Kajiwara, T.; Takemoto, S.


    Based on the electrical logging data of the existed well and Schlumberger sounding data obtained in 1974, a two-dimensional inversion analysis of the specific resistance profile was conducted at the Akinomiya geothermal field, Akita Prefecture. From the electrical logging data, relationships between the geology and the specific resistance were illustrated. The specific resistance values of basement rocks showed more than 100 ohm-m, which were higher than those of the other seams. Intrusive rocks and tuffs in the basement rocks showed locally low values less than 100 ohm-m. Younger volcanic rocks showed low values around 10 ohm-m. As a result of the two-dimensional inversion analysis, the basement rocks could be detected as high specific resistance layers. Accordingly, it was considered that the basement rocks in this field can be detected as high specific resistance layers by analyzing the results of field survey sufficiently. Low specific resistance zones were observed in the shallow depth, which corresponded to the fumarolic gases. There were some layers with remarkably varied specific resistance values, which were considered to be related with alteration. 6 refs., 3 figs.

  4. Geothermal exploration technology. Annual report, 1978

    Energy Technology Data Exchange (ETDEWEB)


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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. Overview of the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market - The Opportunities and Challenges for Expanding Geothermal Energy in a Competitive Supply Market

    Energy Technology Data Exchange (ETDEWEB)

    Mock, John E.; Budraja, Vikram; Jaros, Richard; Yamaguchi, Tsutomu; Hinrichs, Thomas C.


    This overview at the Geothermal Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Technology Advancements to Support Growth in Geothermal Power Sales in a Dynamic Utility Market'' by John E. Mock; ''Geothermal Energy Market in Southern California: Past, Present and Future'' by Vikram Budraja; ''Taking the High Ground: Geothermal's Place in the Revolving Energy Market'' by Richard Jaros; ''Recent Developments in Japan's Hot Dry Rock Program'' by Tsutomu Yamaguchi; and ''Options in the Eleventh Year for Interim Standard Offer Number Four Contracts'' by Thomas C. Hinrichs.

  7. Assessment of Moderate- and High-Temperature Geothermal Resources of the United States (United States)

    Williams, Colin F.; Reed, Marshall J.; Mariner, Robert H.; DeAngelo, Jacob; Galanis, S. Peter


    Scientists with the U.S. Geological Survey (USGS) recently completed an assessment of our Nation's geothermal resources. Geothermal power plants are currently operating in six states: Alaska, California, Hawaii, Idaho, Nevada, and Utah. The assessment indicates that the electric power generation potential from identified geothermal systems is 9,057 Megawatts-electric (MWe), distributed over 13 states. The mean estimated power production potential from undiscovered geothermal resources is 30,033 MWe. Additionally, another estimated 517,800 MWe could be generated through implementation of technology for creating geothermal reservoirs in regions characterized by high temperature, but low permeability, rock formations.

  8. City of El Centro geothermal energy utility core field experiment. Final report, February 16, 1979-November 30, 1984

    Energy Technology Data Exchange (ETDEWEB)

    Province, S.G.; Sherwood, P.B.


    The City of El Centro was awarded a contract in late 1978 to cost share the development of a low to moderate temperature geothermal resource in the City. The resource would be utilized to heat, cool and provide hot water to the nearby Community Center. In December 1981, Thermal 1 (injector) was drilled to 3970 feet. In January 1982, Thermal 2 (producer) was drilled to 8510 feet. Before testing began, fill migrated into both wells. Both wells were cleaned out. A pump was installed in the producer, but migration of fill again into the injector precluded injection of produced fluid. A short term production test was undertaken and results analyzed. Based upon the analysis, DOE decided that the well was not useful for commercial production due to a low flow rate, the potential problems of continued sanding and gasing, and the requirement to lower the pump setting depth and the associated costs of pumping. There was no commercial user found to take over the wells. Therefore, the wells were plugged and abandoned. The site was restored to its original condition.

  9. MT2-D inversion analysis in Kakkonda geothermal field; Kakkonda chinetsu chiiki ni okeru MT ho nijigen kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, K.; Takasugi, S. [Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan); Miyazaki, S. [Japan Metals and Chemicals Co. Ltd., Tokyo (Japan); Uchida, T. [New Energy and Industrial Technology Development Organization, Tokyo, (Japan)


    Data, collected from an MT method-assisted survey conducted in the Kakkonda geothermal region in 1987, was re-examined, and a new structure was found. The review was carried out by use of a 2D analysis in the TM mode. According to the 1D analysis of 1987 and the geological data gathered then, it is estimated that the resistivity structure of this region runs in the northwest-southeast direction. A northeast-southwest traverse line was set for this analysis, orthogonal to the strike, and the impedance at each observation spot was caused to rotate to this direction across the whole range of frequency. Furthermore, in 1994-95, surveys were conducted using arrayed CSMT/MT methods. All these sum up to indicate that a high-resistivity region extends northwest in the southwestern part of the Kakkonda river but that there exists a low-resistivity region of several 10 Ohm m centering about the B traverse line. The high-resistivity region deep in the ground being the target of excavation in the Kakkonda region, to collect knowledge about this high-resistivity is important, and here the effectiveness of the 2d analysis has been verified. 5 refs., 11 figs.

  10. Three dimensional interpretations of single-well electromagnetic data for geothermal applications

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, Hung-Wen; Lee, Ki Ha


    An efficient 3-D electromagnetic (EM) inversion algorithm has been developed for geothermal applications and tested successfully using a set of single-hole EM logging data. The data was collected at an oil field undergoing CO{sub 2} injection in southern California using a single-hole EM tool, Geo-BILT, developed by Electromagnetic Instruments, Inc (EMI). The tool is equipped with a multi-component source, and multi-component receivers at different separations. The inversion result provides a reasonable electrical conductivity image to a distance of 10 m from the well, and illustrates several zones with lateral conductivity variations that could not be resolved with traditional induction logging tools. The successful case study demonstrates potential applications of the tool and software for characterizing fracture systems in geothermal reservoirs.

  11. Heber geothermal binary demonstration plant: Design, construction, and early startup: Topical report

    Energy Technology Data Exchange (ETDEWEB)

    Riley, J. R.


    Study of the concept for a large commercial size binary-cycle geothermal demonstration plant began in 1974. It was perceived that such a project would fill the need to advance the art of binary-cycle technology to the point that it could be used on a large scale for the development of moderate temperature geothermal resources. The Plant is rated at 45 MWe (net) and is located near Heber in the Imperial Valley of California. Construction began in June 1983 and as completed in June 1985. This report presents the results of design studies and field experiments that provided the data for detailed design. It discusses the plant's final design, highlights the logic behind key design decisions, and gives project costs. It describes the planned three-year test and demonstration program. It also includes a list of reports, studies, project documents, and technical papers related to the project.

  12. Tapping the main stream of geothermal energy (United States)


    The development of geothermal energy resources in the United States is discussed. The distribution of underground water resources at temperatures above 90 C and depths up to 3 km in the continental U.S. is examined, and it is pointed out that whereas geothermal resources have been detected under 24 states, only 220 quadrillion Btu of energy recoverable as 24 GW of electricity for 30 years has been conclusively located, all of it in the western states. Direct-flash technology, which generates electricity from hydrothermal fluid at a temperature above 210 C with an efficiency of 15% is presented, and the binary cycle technology required to generate electricity from lower-temperature fluids such as those in the 180 C reservoir of low-salinity brine at Heber in southern California is examined in detail. Questions of minerals and heat control in a geothermal turbine system and the environmental emissions from geothermal plants are addressed. The geothermal resources of the United States are classified as petrothermal, geopressurized and hydrothermal, and methods for extracting heat from these dry rocks, pressurized water and natural gas deposits and systems of steam and hot water are indicated. It is concluded that as fossil fuel energy costs rise, the trend favors geothermal energy, particularly that which can be developed from known hydrothermal resources

  13. Direct Use Applications of Geothermal Resources at Desert Hot Springs, California. Final Report, May 23, 1977--July 31, 1978. Volume I. Summary of Findings

    Energy Technology Data Exchange (ETDEWEB)



    The geothermal resources underlying the City of Desert Hot Springs were described in terms of anticipated geophysical, geochemical, and hydrological characteristics, based upon existing well log data, geologic surveys, and limited wellflow tests. The needs of the City were determined on the basis of its general plan, the City's 1976 census, load survey and a public acceptance survey. Then a broad range of potential nonelectric applications was surveyed in individual as well as energy cascading systems to identify the matchup of the resource and needs of the city. Applications investigated included space conditioning, space/water heating, car wash, agriculture/horticulture, and aquaculture operations. The list of applications so derived was assessed in light of technological, socio-economic, environmental, institutional, and market considerations to determine target opportunities for DHS as well as on a broad regional basis. Those systems which survived the initial screening were subjected to detailed parametric studies focused on determining tradeoffs among performance, cost, size, compatibility with off-the-shelf hardware, etc. A detailed analysis of the engineering and economic aspects of the most promising systems was then performed. Factors considered included technological problems and risks, status of supporting technologies, net energy ratios, costs, market, displacement of fossil fuels, and economic benefit to the community.

  14. Slimhole drilling for geothermal exploration

    Energy Technology Data Exchange (ETDEWEB)

    Finger, J.T. [Sandia National Labs., Albuquerque, NM (United States). Geothermal Research Dept.


    Sandia National Laboratories manages the US Department of Energy program for slimhole drilling. The principal objective of this program is to expand proven geothermal reserves through increased exploration, made possible by lower-cost slimhole drilling. For this to be a valid exploration method, however, it is necessary to demonstrate that slimholes yield enough data to evaluate a geothermal reservoir, and that is the focus of Sandia`s current research. Sandia negotiated an agreement with Far West Capital, which operates the Steamboat Hills geothermal field, to drill and test an exploratory slimhole on their lease. The principal objectives for the slimhole were development of slimhole testing methods, comparison of slimhole data with that from adjacent production-size wells, and definition of possible higher-temperature production zones lying deeper than the existing wells.

  15. Federal Geothermal Research Program Update, FY 2000

    Energy Technology Data Exchange (ETDEWEB)

    Renner, Joel Lawrence


    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.

  16. Insight into the Geothermal Structure in Chingshui, Ilan, Taiwan

    Directory of Open Access Journals (Sweden)

    Lun-Tao Tong


    Full Text Available The Chingshui geothermal field is the largest known productive geothermal area in Taiwan. The purpose of this paper is to delineate this geothermal structure by integrating geophysical data and borehole information. The existence of a magma chamber in the shallow crust and shallow intrusive igneous rock results in a high heat flow and geothermal gradient; furthermore, the NE deep fault system within the meta-sandstones provides meteoric recharge from a higher elevation to artesianally drive the geothermal system. There is evidence that geothermal fluid deeply circulated within the fracture zone and was heated by a deeply located body of hot rock. The geothermal reservoir of the Chingshui geothermal field might be related to the fracture zone of the Chingshuihsi fault. It is bounded by the C-fault in the north and Xiaonanao fault in the south. Based on information obtained from geophysical interpretations and well logs, a 3-D geothermal conceptual model is constructed in this study. Further, the geothermal reservoir is confined to an area that is 260 m in width, N21°W, 1.5 km in length, and has an 80° dip toward the NE. Ahigh-temperature zone is found in the SE region of the reservoir, which is about 500 m in length; this zone is located near the intersection of the Chingshuihsi and Xiaonanao faults. An area on the NE side of the high-temperature zone has been recommended for the drilling of production wells for future geothermal development.

  17. Geologic field-trip guide to Medicine Lake Volcano, northern California, including Lava Beds National Monument (United States)

    Donnelly-Nolan, Julie M.; Grove, Timothy L.


    Medicine Lake volcano is among the very best places in the United States to see and walk on a variety of well-exposed young lava flows that range in composition from basalt to rhyolite. This field-trip guide to the volcano and to Lava Beds National Monument, which occupies part of the north flank, directs visitors to a wide range of lava flow compositions and volcanic phenomena, many of them well exposed and Holocene in age. The writing of the guide was prompted by a field trip to the California Cascades Arc organized in conjunction with the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) quadrennial meeting in Portland, Oregon, in August of 2017. This report is one of a group of three guides describing the three major volcanic centers of the southern Cascades Volcanic Arc. The guides describing the Mount Shasta and Lassen Volcanic Center parts of the trip share an introduction, written as an overview to the IAVCEI field trip. However, this guide to Medicine Lake volcano has descriptions of many more stops than are included in the 2017 field trip. The 23 stops described here feature a range of compositions and volcanic phenomena. Many other stops are possible and some have been previously described, but these 23 have been selected to highlight the variety of volcanic phenomena at this rear-arc center, the range of compositions, and for the practical reason that they are readily accessible. Open ground cracks, various vent features, tuffs, lava-tube caves, evidence for glaciation, and lava flows that contain inclusions and show visible evidence of compositional zonation are described and visited along the route.

  18. Geothermal pilot study final report: creating an international geothermal energy community

    Energy Technology Data Exchange (ETDEWEB)

    Bresee, J.C.; Yen, W.W.S.; Metzler, J.E. (eds.)


    The Geothermal Pilot Study under the auspices of the Committee on the Challenges of Modern Society (CCMS) was established in 1973 to apply an action-oriented approach to international geothermal research and development, taking advantage of the established channels of governmental communication provided by the North Atlantic Treaty Organization (NATO). The Pilot Study was composed of five substudies. They included: computer-based information systems; direct application of geothermal energy; reservoir assessment; small geothermal power plants; and hot dry rock concepts. The most significant overall result of the CCMS Geothermal Pilot Study, which is now complete, is the establishment of an identifiable community of geothermal experts in a dozen or more countries active in development programs. Specific accomplishments include the creation of an international computer file of technical information on geothermal wells and fields, the development of studies and reports on direct applications, geothermal fluid injection and small power plants, and the operation of the visiting scientist program. In the United States, the computer file has aready proven useful in the development of reservoir models and of chemical geothermometers. The state-of-the-art report on direct uses of geothermal energy is proving to be a valuable resource document for laypersons and experts in an area of increasing interest to many countries. Geothermal fluid injection studies in El Salvador, New Zealand, and the United States have been assisted by the Reservoir Assessment Substudy and have led to long-range reservoir engineering studies in Mexico. At least seven small geothermal power plants are in use or have been planned for construction around the world since the Small Power Plant Substudy was instituted--at least partial credit for this increased application can be assigned to the CCMS Geothermal Pilot Study. (JGB)

  19. A guide to geothermal energy and the environment

    Energy Technology Data Exchange (ETDEWEB)

    Kagel, Alyssa; Bates, Diana; Gawell, Karl


    Geothermal energy, defined as heat from the Earth, is a statute-recognized renewable resource. The first U.S. geothermal power plant, opened at The Geysers in California in 1960, continues to operate successfully. The United States, as the world's largest producer of geothermal electricity, generates an average of 15 billion kilowatt hours of power per year, comparable to burning close to 25 million barrels of oil or 6 million short tons of coal per year. Geothermal has a higher capacity factor (a measure of the amount of real time during which a facility is used) than many other power sources. Unlike wind and solar resources, which are more dependent upon weather fluctuations and climate changes, geothermal resources are available 24 hours a day, 7 days a week. While the carrier medium for geothermal electricity (water) must be properly managed, the source of geothermal energy, the Earth's heat, will be available indefinitely. A geothermal resource assessment shows that nine western states together have the potential to provide over 20 percent of national electricity needs. Although geothermal power plants, concentrated in the West, provide the third largest domestic source of renewable electricity after hydropower and biomass, they currently produce less than one percent of total U.S. electricity.

  20. Evaluation of CO2-Fluid-Rock Interaction in Enhanced Geothermal Systems: Field-Scale Geochemical Simulations

    Directory of Open Access Journals (Sweden)

    Feng Pan


    Full Text Available Recent studies suggest that using supercritical CO2 (scCO2 instead of water as a heat transmission fluid in Enhanced Geothermal Systems (EGS may improve energy extraction. While CO2-fluid-rock interactions at “typical” temperatures and pressures of subsurface reservoirs are fairly well known, such understanding for the elevated conditions of EGS is relatively unresolved. Geochemical impacts of CO2 as a working fluid (“CO2-EGS” compared to those for water as a working fluid (H2O-EGS are needed. The primary objectives of this study are (1 constraining geochemical processes associated with CO2-fluid-rock interactions under the high pressures and temperatures of a typical CO2-EGS site and (2 comparing geochemical impacts of CO2-EGS to geochemical impacts of H2O-EGS. The St. John’s Dome CO2-EGS research site in Arizona was adopted as a case study. A 3D model of the site was developed. Net heat extraction and mass flow production rates for CO2-EGS were larger compared to H2O-EGS, suggesting that using scCO2 as a working fluid may enhance EGS heat extraction. More aqueous CO2 accumulates within upper- and lower-lying layers than in the injection/production layers, reducing pH values and leading to increased dissolution and precipitation of minerals in those upper and lower layers. Dissolution of oligoclase for water as a working fluid shows smaller magnitude in rates and different distributions in profile than those for scCO2 as a working fluid. It indicates that geochemical processes of scCO2-rock interaction have significant effects on mineral dissolution and precipitation in magnitudes and distributions.

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

    Energy Technology Data Exchange (ETDEWEB)


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

  2. Recovery of secular deformation field of Mojave Shear Zone in Southern California from historical terrestrial and GPS measurements (United States)

    Liu, Shaozhuo; Shen, Zheng-Kang; Bürgmann, Roland


    The 1992 Mw 7.3 Landers and 1999 Mw 7.1 Hector Mine earthquakes struck the Eastern California Shear Zone (ECSZ) in the Mojave Desert, Southern California. Coseismic and postseismic deformation from these events affect efforts to use Global Positioning System (GPS) observations collected since these events to establish a secular surface velocity field, especially in the near field of the coseismic ruptures. We devise block motion models constrained by both historical pre-Landers triangulation and trilateration observations and post-Landers GPS measurements to recover the secular deformation field and differentiate the postseismic transients in the Mojave region. Postseismic transients are found to remain in the Southern California Earthquake Center Crustal Motion Map Version 4, Plate Boundary Observatory, and Scripps Orbit and Permanent Array Center GPS velocity solutions in the form of 2-3 mm/yr excess right-lateral shear across the Landers and Hector Mine coseismic ruptures. The cumulative deformation rate across the Mojave ECSZ is 13.2-14.4 mm/yr, at least twice the geologic rate since the late Pleistocene (≤6.2 ± 1.9 mm/yr). Postseismic GPS time series based on our secular velocity field reveal enduring late-stage transient motions in the near field of the coseismic ruptures that provide new constraints on the rheological structure of the lower crust and upper mantle.

  3. Spatial analysis of noise emission at the Los Azufres geothermal field, Mich.; Analisis espacial de emision de ruido en el campo geotermico de Los Azufres, Mich.

    Energy Technology Data Exchange (ETDEWEB)

    Camarena Magana, Emilio; Ordaz Mendez, Christian A. [Comision Federal de Electricidad, Residencia de Los Azufres, Morelia, Michoacan (Mexico)]. E-mail:


    To verify noise emissions from the usual activities in an operating geothermal field, noise measurements were carried out in a 4.2 km{sup 2} area in the southern zone of the Los Azufres, Mich., geothermal field. There are seven production wells operating here and three abandoned wells. The average noise emission in the southern zone was 36.5 decibels (dB), regarded as the natural reading of environmental-noise emission. In the Christmas (valves) tree for operating production wells, the noise ranges from 70.9 to 91.7 dB, while in open discharging valves for steam-pipes, the noise can reach 118 dB. In Mexico the maximum permissible limit of noise on the periphery of a property is 68 dB in daytime and 65 dB at night. Based on measurements made at the periphery of lots where the geothermal wells are located, four out of seven production wells measured do not exceed the maximum allowable level, while the other three seem to exceed it. However no definite limits exist for the lots. It is recommended that the measurement points as indicated by the official standard in environmental matters be re-established, which will enable noise emissions by several wells that have exceeded the permissible limit, to actually fall within it. [Spanish] Se realizaron mediciones sonicas en un area de 4.2 km{sup 2} localizada en la zona sur del campo geotermico de Los Azufres, Mich., a fin de verificar la emision de ruido asociada a las actividades usuales en un campo geotermico en operacion. En esta area se encuentran siete pozos productores en operacion y tres pozos abandonados. La emision promedio de ruido en estos ultimos fue de 36.5 decibeles (dB), considerandose como la condicion natural de emision de ruido ambiental. En el arbol de valvulas de los pozos productores en operacion el ruido va de los 70.9 a los 91.7 dB, mientras que en valvulas abiertas de descarga de vaporductos la emision puede llegar hasta los 118 dB. En Mexico el limite maximo permisible de ruido en la periferia de

  4. Some New Constraints On The Stratigraphic And Structural Setting Of The Soda Lake Geothermal Field, Churchill County, Nevada - McLACHLAN, Holly S. and FAULDS, James E., Nevada Bureau of Mines and Geology, University of Nevada, Reno, NV 89557 (United States)

    McLachlan, H. S.


    Our research group is currently conducting a regional survey to identify favorable structural settings of producing and prospective geothermal fields in the Great Basin. The Soda Lake geothermal field - one of the oldest consistently producing fields in this study region - is located in west-central Nevada near the heart of the Carson Sink. Producing and prospective geothermal fields in the surrounding highlands are hosted in 1) fault termination zones (Desert Queen), 2) accommodation zones (Brady's Hot Springs) and 3) fault step-overs (Desert Peak). However, the structural setting is challenging to identify at the Soda Lake field, because it lies in the central part of a large basin with no nearby bedrock exposures. The well field at Soda Lake is centered ~3.5 km NNE of the Holocene Soda Lake maar, from which it takes its name. The geothermal field was identified serendipitously during the drilling of an irrigation survey well in the early 20th century. Modern exploratory drilling at the field began in the mid-1970s and has continued sporadically to the present. There are currently more than 28 500+ m wells at and near the production site. The exceptional drilling density at Soda Lake allows for comparatively reliable correlation of stratigraphy in the subsurface below the feature-poor Carson Sink. Stratigraphy in the Soda Lake geothermal area is relatively "layer cake" at the scale of the well field. Unconsolidated sediments extend more than 1000 m below surface. The upper few hundred meters are composed of fluvial and lacustrine sediments derived from Sierran batholith source rocks. The deeper basin fill derives from more proximal mafic to felsic Miocene volcanic rocks along the basin margins. At ~450-650 m depth, basin sediments are interrupted by a 5.11 Ma trachytic basalt of restricted lateral extent and variable thickness. Most wells intercept ~50-250 m of fine lacustrine sediments below this basalt body before intercepting the basin floor. Basin floor rocks

  5. Multidisciplinary exploratory study of a geothermal resource in the active volcanic arc of Basse-Terre (Guadeloupe, Lesser Antilles) (United States)

    Navelot, Vivien; Favier, Alexiane; Géraud, Yves; Diraison, Marc; Corsini, Michel; Verati, Chrystèle; Lardeaux, Jean-Marc; Mercier de Lépinay, Jeanne; Munschy, Marc


    The GEOTREF project (high enthalpy geothermal energy in fractured reservoirs), supported by the French government program, "Investissements d'avenir" develops a sustainable geothermal resource in the Vieux Habitants area, 8-km south of the currently exploited Bouillante geothermal field. The Basse Terre Island is a recent volcanic arc (geothermal gradient of 70 ˚ C/km.

  6. Geothermal Technologies Program: Alaska

    Energy Technology Data Exchange (ETDEWEB)


    This fact sheets provides a summary of geothermal potential, issues, and current development in Alaska. This fact sheet was developed as part of DOE's GeoPowering the West initiative, part of the Geothermal Technologies Program.

  7. Hot Dry Rock; Geothermal Energy

    Energy Technology Data Exchange (ETDEWEB)



    The commercial utilization of geothermal energy forms the basis of the largest renewable energy industry in the world. More than 5000 Mw of electrical power are currently in production from approximately 210 plants and 10 000 Mw thermal are used in direct use processes. The majority of these systems are located in the well defined geothermal generally associated with crustal plate boundaries or hot spots. The essential requirements of high subsurface temperature with huge volumes of exploitable fluids, coupled to environmental and market factors, limit the choice of suitable sites significantly. The Hot Dry Rock (HDR) concept at any depth originally offered a dream of unlimited expansion for the geothermal industry by relaxing the location constraints by drilling deep enough to reach adequate temperatures. Now, after 20 years intensive work by international teams and expenditures of more than $250 million, it is vital to review the position of HDR in relation to the established geothermal industry. The HDR resource is merely a body of rock at elevated temperatures with insufficient fluids in place to enable the heat to be extracted without the need for injection wells. All of the major field experiments in HDR have shown that the natural fracture systems form the heat transfer surfaces and that it is these fractures that must be for geothermal systems producing from naturally fractured formations provide a basis for directing the forthcoming but, equally, they require accepting significant location constraints on HDR for the time being. This paper presents a model HDR system designed for commercial operations in the UK and uses production data from hydrothermal systems in Japan and the USA to demonstrate the reservoir performance requirements for viable operations. It is shown that these characteristics are not likely to be achieved in host rocks without stimulation processes. However, the long term goal of artificial geothermal systems developed by systematic

  8. Field calibrations of a low-cost aerosol sensor at a regulatory monitoring site in California (United States)

    Holstius, D. M.; Pillarisetti, A.; Smith, K. R.; Seto, E.


    Health effects attributed to ambient fine particulate matter (PM2.5) now rank it among the risk factors with the highest health burdens in the world, but existing monitoring infrastructure cannot adequately characterize spatial and temporal variability in urban PM2.5 concentrations, nor in human population exposures. The development and evaluation of more portable and affordable monitoring instruments based on low-cost sensors may offer a means to supplement and extend existing infrastructure, increasing the density and coverage of empirical measurements and thereby improving exposure science and control. Here, we report on field calibrations of a custom-built, battery-operated aerosol monitoring instrument we developed using low-cost, off-the-shelf optical aerosol sensors. We calibrated our instruments using 1 h and 24 h PM2.5 data from a class III US EPA Federal Equivalent Method (FEM) PM2.5 β-attenuation monitor in continuous operation at a regulatory monitoring site in Oakland, California. We observed negligible associations with ambient humidity and temperature; linear corrections were sufficient to explain 60% of the variance in 1 h reference PM2.5 data and 72% of the variance in 24 h data. Performance at 1 h integration times was comparable to commercially available optical instruments costing considerably more. These findings warrant further exploration of the circumstances under which this class of aerosol sensors may profitably be deployed to generate improved PM2.5 data sets.

  9. Constraints on geothermal reservoir volume change calculations from InSAR surface displacements and injection and production data (United States)

    Kaven, J. Ole; Barbour, Andrew J.; Ali, Tabrez


    Continual production of geothermal energy at times leads to significant surface displacement that can be observed in high spatial resolution using InSAR imagery. The surface displacement can be analyzed to resolve volume change within the reservoir revealing the often-complicated patterns of reservoir deformation. Simple point source models of reservoir deformation in a homogeneous elastic or poro-elastic medium can be superimposed to provide spatially varying, kinematic representations of reservoir deformation. In many cases, injection and production data are known in insufficient detail; but, when these are available, the same Green functions can be used to constrain the reservoir deformation. Here we outline how the injection and production data can be used to constrain bounds on the solution by posing the inversion as a quadratic programming with inequality constraints and regularization rather than a conventional least squares solution with regularization. We apply this method to InSAR-derived surface displacements at the Coso and Salton Sea Geothermal Fields in California, using publically available injection and production data. At both geothermal fields the available surface deformation in conjunction with the injection and production data permit robust solutions for the spatially varying reservoir deformation. The reservoir deformation pattern resulting from the constrained quadratic programming solution is more heterogeneous when compared to a conventional least squares solution. The increased heterogeneity is consistent with the known structural controls on heat and fluid transport in each geothermal reservoir.

  10. Mineralization associated with scale and altered rock and pipe fragments from the Berlín geothermal field, El Salvador; implications for metal transport in natural systems (United States)

    Raymond, Jasmin; Williams-Jones, Anthony E.; Clark, James R.


    Composite fragments sampled at solid collectors and drains of two-phase, re-injection, and vapour pipelines of the Berlín geothermal field, El Salvador, consist mainly of sulphide- and electrum-bearing aluminium-rich amorphous silica scale, sulphide- and electrum-bearing saponitic/vermiculitic clay from the reservoir, and altered metallic pipe linings containing As-S-bearing iron oxide-oxyhydroxide grains. Siliceous and clay-rich precipitates contain concentrations of gold and silver in excess of 180 and 8000 ppm, respectively, and appreciable concentrations of copper, lead, zinc, and antimony. Altered iron fragments contain substantial arsenic. Copper, lead, and zinc occur mainly as chalcopyrite, galena, and sphalerite, respectively, in amorphous silica and clay; near the surface, chalcopyrite transported from depth alters to bornite. Gold and silver occur mainly as electrum, which deposited with base metal sulphides in the clay precipitates, and amorphous silica at higher levels in the well. Electrum precipitates in the wells due to the rapid drop in temperature and loss of H 2S associated with boiling. The concentration of gold in vapour is ˜4 times greater than that in water from associated wellheads. This suggests that gold can be transported efficiently by vapour, and implies that such transport may be important in the formation of some hydrothermal ore deposits.

  11. Geochemical evidences of the boiling phenomena in Los Humeros geothermal field; Evidencias geoquimicas del fenomeno de ebullicion en el campo de Los Humeros

    Energy Technology Data Exchange (ETDEWEB)

    Munguia Bracamontes, Fernando; Lopez Mendiola, Juan Manuel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)


    The geochemical behavior of the fluids in the geothermal field Los Humeros suggests the existence of a reservoir of relatively low permeability, with hydrostatic pressure gradients and thermodynamic conditions of pressure-temperature close to the boiling point in stationary conditions, that is, non-disturbed. Nevertheless, the fluid geochemistry also indicates the presence of steam under stationary conditions, mainly in the fault, fracture, fissure, etc. zones. The steam diminishes progressively as the extraction time increases, being replaced by boiling fluid. [Espanol] El comportamiento geoquimico de los fluidos en el campo geotermico de Los Humeros sugiere la existencia de un yacimiento de relativa baja permeabilidad, con gradientes de presion hidrostatica y condiciones termodinamicas de presion-temperatura cercanas al punto de ebullicion a condiciones estables; es decir, no perturbadas. Sin embargo, la geoquimica de los fluidos tambien indica la existencia de vapor bajo condiciones estables, principalmente en las zonas de fallas, fracturas, fisuras, etc. El vapor disminuye progresivamente conforme aumenta el tiempo de extraccion, siendo reemplazado por fluido en ebullicion.

  12. Environmental framework for the development of the Los Humeros, Puebla geothermal field; Contexto ambiental del desarrollo del campo geotermico de Los Humeros, Puebla

    Energy Technology Data Exchange (ETDEWEB)

    Pastrana Melchor, Eugenio J.; Fernandez Solorzano, Maria Elena; Mendoza Rangel, Ernesto; Hernandez Ayala, Cuauhtemoc [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)


    The construction, operation and maintenance of the Los Humeros, Puebla, geothermal field were undertaken in accordance with Mexican environmental regulations. The resolutions on environmental impacts, license for atmospheric pollution prevention, concession title for exploitation and use of national waters, permission for wastewater discharging services, company registration for producing dangerous wastes and fulfillment of all conditions noted in the documents show the applicable environmental laws for the project have been followed. [Spanish] La construccion, operacion y mantenimiento del campo geotermoelectrico Los Humeros, Puebla, se ha llevado a cabo dentro del marco juridico ambiental vigente en Mexico. Las resoluciones en materia de impacto ambiental, la licencia en materia de prevencion de la contaminacion de la atmosfera, el titulo de concesion para explorar, usar o aprovechar aguas nacionales, el permiso para descargar aguas residuales domesticas, el registro como empresa generadora de residuos peligrosos, y el cumplimiento de las disposiciones y condicionantes establecidos en cada uno de estos documentos, evidencian la observancia de la legislacion ambiental aplicable al proyecto.

  13. Geothermal energy in Nevada

    Energy Technology Data Exchange (ETDEWEB)


    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)

  14. Final Technical Resource Confirmation Testing at the Raft River Geothermal Project, Cassia County, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Glaspey, Douglas J.


    Incorporates the results of flow tests for geothermal production and injection wells in the Raft River geothermal field in southern Idaho. Interference testing was also accomplished across the wellfield.

  15. Synthesis of gravity, magnetic and thermal studies at the Las Tres Virgenes geothermal zone, Baja California Sur, Mexico. Sintesis de los estudios de gravimetria, magnetometria y termometria en la zona geotermica de Las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Estrada, Gerardo (Departamento de Exploracion, Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)); Gonzalez Lopez, Macario (Residencia General de Cerro Prieto, Mexicali (Mexico))


    Las Tres Virgenes geothermal zone is located in the NE-SW central sector of a sigmoidal basin that regionally has a NW-SE trend. In the local deepest zone there is a NE-SE granodioritic basement horst acting as hydrologic barrier, that makes the fluids flow up. After moving in a direction parallel to the local horst, waters continue its regional SE-NW movement controlled by regional tectonics. The flanks of the granodioritic basement horst, and local N-S faulting act as fluid paths in the hydrothermal zone, but regional NW-SE regional faults determine the general flow direction. Both regional and local tectonics show magnetic evidences of the emplacement of magmatic bodies of intermediate to basic composition. Those along NW-SE trends are more noticeable but we consider they are not the present day heat source. Intermediate magmatism along NE-SW local trend seems to be less extensive but it is younger, so, we consider it constitutes the heat source of the hydrothermal system. Thermal data suggest that the heat source is located below the volcanic chain toward the S or SW of the wells, phenomena related with the general displacement of magmatism from NE to SW along the volcanic chain. However, recen