The Experts below are selected from a list of 16029 Experts worldwide ranked by ideXlab platform

Wei Zhang - One of the best experts on this subject based on the ideXlab platform.

David D. Blackwell - One of the best experts on this subject based on the ideXlab platform.

  • THERMAL REGIME IN THE DIXIE VALLEY Geothermal System
    2020
    Co-Authors: David D. Blackwell, Bobbie Golan, Dick Beniot
    Abstract:

    The thermal setting of the Dixie Valley Geothermal System is summarized. New data from shallow and deep wells require that the Geothermal System be a complex, steeply dipping fault zone with flow on a number of strands of the fault zone rather than a single fault plane. As a result of this new model for the reservoir in Dixie Valley there appear to be numerous untested structures with evidence of fluid flow. The model has applications to other fault controlled, deep circulation Systems.

  • understanding the chena hot springs alaska Geothermal System using temperature and pressure data from exploration boreholes
    Geothermics, 2008
    Co-Authors: Kamil Erkan, Gwen Holdmann, Walter R Benoit, David D. Blackwell
    Abstract:

    Abstract Chena Hot Springs is a small, moderate temperature, deep circulating Geothermal System, apparently typical of those associated to hot springs of interior Alaska. Multi-stage drilling was used in some exploration boreholes and was found to be useful for understanding subsurface flow characteristics and developing a conceptual model of the System. The results illustrate how temperature profiles illuminate varying pressure versus depth characteristics and can be used alone in cases where staged drilling is not practical. The extensive exploration activities helped define optimal fluid production and injection areas, and showed that the System could provide sufficient hot fluids (∼57 °C) to run a 400-kWe binary power plant, which came on line in 2006.

  • Assessment of the Enhanced Geothermal System Resource Base of the United States
    Natural Resources Research, 2006
    Co-Authors: David D. Blackwell, Petru T. Negraru, Maria C. Richards
    Abstract:

    This paper describes an assessment of the enhanced Geothermal System (EGS) resource base of the conterminous United States, using constructed temperature at depth maps. The temperature at depth maps were computed from 3 to 10 km, for every km. The methodology is described. Factors included are sediment thickness, thermal conductivity variations, distribution of the radioactive heat generation and surface temperature based on several geologic models of the upper 10 km of the crust. EGS Systems are extended in this paper to include coproduced Geothermal energy, and geopressured resources.A table is provided that summarizes the resource base estimates for all components of the EGS Geothermal resource. By far, the conduction-dominated components of EGS represent the largest component of the U.S. resource. Nonetheless, the coproduced resources and geopressured resources are large and significant targets for short and intermediate term development. There is a huge resource base between the depths of 3 and 8 km, where the temperature reaches 150–250°C. Even if only 2% of the conventional EGS resource is developed, the energy recovered would be equivalent to roughly 2,500 times the annual consumption of primary energy in the U.S. in 2006. Temperatures above 150°C at those depths are more common in the active tectonic regions of the western conterminous U.S., but are not confined to those areas. In the central and eastern U.S. there are identified areas of moderate size that are of reasonable grade and probably small areas of much higher grade than predicted by this analyses. However because of the regional (the grid size is 5′ × 5′) scale of this study such potentially promising sites remain to be identified.Several possible scenarios for EGS development are discussed. The most promising and least costly may to be developments in abandoned or shut-in oil and gas fields, where the temperatures are high enough. Because thousands of wells are already drilled in those locations, the cost of producing energy from such fields could be significantly lowered. In addition many hydrocarbon fields are producing large amounts of co-produced water, which is necessary for Geothermal development. Although sustainability is not addressed in this study, the resource is so large that in at least some scenarios of development the Geothermal resource is sustainable for long periods of time.

Martin Hand - One of the best experts on this subject based on the ideXlab platform.

  • seismic mapping and geomechanical analyses of faults within deep hot granites a workflow for enhanced Geothermal System projects
    Geothermics, 2015
    Co-Authors: Abul H Khair, Dennis Cooke, Martin Hand
    Abstract:

    Abstract Areas with deep seated radioactive granites are considered targets for enhanced Geothermal System (EGS) projects. These areas normally exhibit high heat flow and temperature anomalies related to granitic bodies. High concentrations of uranium within the granites are the most likely cause of the anomalous temperatures. Elevated temperatures are also resulted to high heat flow and thick sedimentary rock cover that includes insulating materials such as coals and gas reservoirs. In this study we investigated the use of 3D seismic amplitudes and attributes to map deep granitic bodies and faults in the Cooper Basin of South Central Australia. We established a workflow for possible geomechanical fluid flow susceptibility analyses for faults that intersect granites. The far field stress tensor must be interpreted through analyses of image logs and formation tests. Our geomechanical analyses models show how this stress tensor affects basement faults interpreted from 3D seismic surveys. Normal stresses, shear stresses, slip tendency, and distance to failure should be modelled for the faults that cut the granites. The optimal orientation of faults that can be possible conduits are then located. We suggest that the optimal injection and production wells should be located at tips of shallow faults that penetrate the granites. We anticipate that short horizontal faults that are located far from other faults will form a more secure fluid conduit. Finally, this study can be a workflow to evaluate the relative merit of future enhanced Geothermal System projects.

Guðmundur Omar Friðleifsson - One of the best experts on this subject based on the ideXlab platform.

  • evolution of fluid rock interaction in the reykjanes Geothermal System iceland evidence from iceland deep drilling project core rn 17b
    Journal of Volcanology and Geothermal Research, 2015
    Co-Authors: Andrew P.g. Fowler, Robert A Zierenberg, P Schiffman, N E Marks, Guðmundur Omar Friðleifsson
    Abstract:

    Abstract We describe the lithology and present spatially resolved geochemical analyses of samples from the hydrothermally altered Iceland Deep Drilling Project (IDDP) drill core RN-17B. The 9.3 m long RN-17B core was collected from the seawater-dominated Reykjanes Geothermal System, located on the Reykjanes Peninsula, Iceland. The nature of fluids and the location of the Reykjanes Geothermal System make it a useful analog for seafloor hydrothermal processes, although there are important differences. The recovery of drill core from the Reykjanes Geothermal System, as opposed to drill cuttings, has provided the opportunity to investigate evolving Geothermal conditions by utilizing in-situ geochemical techniques in the context of observed paragenetic and spatial relationships of alteration minerals. The RN-17B core was returned from a vertical depth of ~ 2560 m and an in-situ temperature of ~ 345 °C. The primary lithologies are basaltic in composition and include hyaloclastite breccia, fine-grained volcanic sandstone, lithic breccia, and crystalline basalt. Primary igneous phases have been entirely pseudomorphed by calcic plagioclase + magnesium hornblende + chlorite + titanite + albitized plagioclase + vein epidote and sulfides. Despite the extensive hydrothermal metasomatism, original textures including hyaloclastite glass shards, lithic clasts, chilled margins, and shell-fragment molds are superbly preserved. Multi-collector LA-ICP-MS strontium isotope ratio ( 87 Sr/ 86 Sr) measurements of vein epidote from the core are consistent with seawater as the dominant recharge fluid. Epidote-hosted fluid inclusion homogenization temperature and freezing point depression measurements suggest that the RN-17B core records cooling through the two-phase boundary for seawater over time to current in-situ measured temperatures. Electron microprobe analyses of hydrothermal hornblende and hydrothermal plagioclase confirm that while alteration is of amphibolite-grade, it is in disequilibrium and the extent of alteration is dependent upon protolith type and water/rock ratio. Alteration in the RN-17B core bares many similarities to that of Type II basalts observed in Mid-Atlantic Ridge samples.

Yoonho Song - One of the best experts on this subject based on the ideXlab platform.

  • observations of hydraulic stimulations in seven enhanced Geothermal System projects
    Renewable Energy, 2015
    Co-Authors: Yoonho Song
    Abstract:

    Numerous stimulation tests have been performed on Enhanced Geothermal System (EGS) or Hot Dry Rock (HDR) projects during the past three decades, however, there is much room for improvement in our knowledge and understanding of the mechanisms of stimulation. This paper investigated the hydraulic stimulation tests carried out on seven EGS or HDR projects where massive volume of fluid was injected into the long open section of the well with interval of tens to hundreds of meters in the crystalline formation. The key characteristic test and performance parameters were defined and collected through extensive survey of stimulation results. Attempts were made to carry out comparative analysis on reservoir conditions, test parameters and test observations. The analysis and discussion suggest that 1) the reservoir stress regime impacts the growth of stimulated region and the reverse faulting stress regime can be favorable for the layout of multiple well System as it may lead to a horizontally or sub-horizontally oriented stimulated zone; 2) the injection pressure for activating shear slip and the associated onset of seismicity is mainly field stress controlled; 3) there is strong dependency of injectivity on injection pressure and a high pressure makes a better hydraulic injectivity during stimulation and consequently afterwards for circulation; 4) the stimulated region and number of induced seismic events are mainly injection volume controlled and the potential strategy to reduce seismic risks is either to extend stimulation in time or to separate stimulation in space; and 5) the differential stress condition is one of the necessary factors to raise a large magnitude event (LME) and the difference of maximum injection pressure achieved over that at onset of seismicity is an important additional factor to induce LMEs.