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Title: Hot dry rock geothermal potential of Roosevelt Hot Springs area: review of data and recommendations

Abstract

The Roosevelt Hot Springs area in west-central Utah possesses several features indicating potential for hot dry rock (HDR) geothermal development. The area is characterized by extensional tectonics and a high regional heat flow of greater than 105 mW/m/sup 2/. The presence of silicic volcanic rocks as young as 0.5 to 0.8 Myr and totaling 14 km/sup 3/ in volume indicates underlying magma reservoirs may be the heat source for the thermal anomaly. Several hot dry wells have been drilled on the periphery of the geothermal field. Information obtained on three of these deep wells shows that they have thermal gradients of 55 to 60/sup 0/C/km and bottom in impermeable Tertiary granitic and Precambrian gneissic units. The Tertiary granite is the preferred HDR reservoir rock because Precambrian gneissic rocks possess a well-developed banded foliation, making fracture control over the reservoir more difficult. Based on a fairly conservative estimate of 160 km/sup 2/ for the thermal anomaly present at Roosevelt Hot Springs, the area designated favorable for HDR geothermal exploration may be on the order of seven times or more than the hydrogeothermal area currently under development.

Authors:
Publication Date:
Research Org.:
Los Alamos National Lab., NM (USA)
OSTI Identifier:
6349353
Report Number(s):
LA-8751-HDR
ON: DE81026668
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; ROOSEVELT HOT SPRINGS; GEOPHYSICAL SURVEYS; HEAT FLOW; HOT-DRY-ROCK SYSTEMS; GEOLOGY; HYDROTHERMAL ALTERATION; MAPS; RESISTIVITY SURVEYS; RESOURCE POTENTIAL; SEISMIC SURVEYS; TECTONICS; TEMPERATURE LOGGING; WATER CHEMISTRY; CHEMISTRY; ELECTRICAL SURVEYS; ENERGY SYSTEMS; GEOTHERMAL SYSTEMS; KGRA; NORTH AMERICA; ROCKY MOUNTAIN REGION; SURVEYS; USA; UTAH; WELL LOGGING; Geothermal Legacy; 150301* - Geothermal Exploration & Exploration Technology- Geophysical Techniques & Surveys

Citation Formats

East, J. Hot dry rock geothermal potential of Roosevelt Hot Springs area: review of data and recommendations. United States: N. p., 1981. Web. doi:10.2172/6349353.
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East, J. Hot dry rock geothermal potential of Roosevelt Hot Springs area: review of data and recommendations. United States. doi:10.2172/6349353.
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East, J. Fri . "Hot dry rock geothermal potential of Roosevelt Hot Springs area: review of data and recommendations". United States. doi:10.2172/6349353. https://www.osti.gov/servlets/purl/6349353.
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@article{osti_6349353,
title = {Hot dry rock geothermal potential of Roosevelt Hot Springs area: review of data and recommendations},
author = {East, J.},
abstractNote = {The Roosevelt Hot Springs area in west-central Utah possesses several features indicating potential for hot dry rock (HDR) geothermal development. The area is characterized by extensional tectonics and a high regional heat flow of greater than 105 mW/m/sup 2/. The presence of silicic volcanic rocks as young as 0.5 to 0.8 Myr and totaling 14 km/sup 3/ in volume indicates underlying magma reservoirs may be the heat source for the thermal anomaly. Several hot dry wells have been drilled on the periphery of the geothermal field. Information obtained on three of these deep wells shows that they have thermal gradients of 55 to 60/sup 0/C/km and bottom in impermeable Tertiary granitic and Precambrian gneissic units. The Tertiary granite is the preferred HDR reservoir rock because Precambrian gneissic rocks possess a well-developed banded foliation, making fracture control over the reservoir more difficult. Based on a fairly conservative estimate of 160 km/sup 2/ for the thermal anomaly present at Roosevelt Hot Springs, the area designated favorable for HDR geothermal exploration may be on the order of seven times or more than the hydrogeothermal area currently under development.},
doi = {10.2172/6349353},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri May 01 00:00:00 EDT 1981},
month = {Fri May 01 00:00:00 EDT 1981}
}
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Technical Report:
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DOI:  10.2172/6349353
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  • ; ; ; ...
    The Acord 1-26 well is a hot, dry well peripheral to the Roosevelt Hot Springs known geothermal resource area (KGRA) in southwestern Utah. The bottom-hole temperature in this 3854-m-deep well is 230/sup 0/C, and the thermal gradient is 54/sup 0/C/km. The basal 685 m, comprised of biotite monzonite and quartz schist and gneiss, is a likely hot, dry rock (HDR) prospect. The hole was drilled in a structural low within the Milford Valley graben and is separated from the Roosevelt KGRA to the east by the Opal Mound Fault and other basin faults. An interpretation of seismic data approximates themore » subsurface structure around the well using the lithology in the Acord 1-26 well. The hole was drilled with a minimum of difficulty, and casing was set to 2411 m. From drilling and geophysical logs, it is deduced that the subsurface blocks of crystalline rock in the vicinity of the Acord 1-26 well are tight, dry, shallow, impermeable, and very hot. A hydraulic fracture test of the crystalline rocks below 3170 m is recommended. Various downhole tools and techniques could be tested in promising HDR regimes within the Acord 1-26 well.« less

  • ; ;
    The theoretical basis for modeling the arrival times of local earthquake P waves at a network of seismic stations is described. A technique for separating the dependence of network arrival times on velocity structure from the dependence on the earthquake location parameters is presented. Commented computer listings of the forward modeling algorithms developed in part under DOE support are given. The local arrival time and Bouguer gravity data sets acquired for the Roosevelt and Leach Hot Springs areas are described. The Leach data were found to be inadequate so the emphasis is on the editing and processing the Roosevelt Hotmore » Springs data prior to inversion. The inversion model for the Roosevelt Hot Springs area obtained from a joint inversion of seismic and gravity data is described. The more robust features of the final model are discussed in light of the known geology and geophysics of the area and are compared to results obtained from related studies. (MHR)« less

  • ; ;
    The Roosevelt Hot Springs Thermal Area is a newly discovered geothermal power prospect. Seven production wells have been drilled with a maximum flow capability averaging 4.5 x 10{sup 5} kg of combined vapor and liquid per hour at a bottom hole temperature of 260 C. The thermal area is located on the western-margin of the Mineral Mountains, which consist dominantly of a Tertiary granitic pluton 32 km long by 8 km wide. Rhyolitic tuffs, flows, and domes cover about 25 km{sup 2} of the crest and west side of the Mineral Mountains within 5 km of the thermal area. Themore » rhyolitic volcanism occurred between 0.8 and 0.5 m.y. ago and constitutes a major Pleistocene thermal event believed to be significant to the evaluation of the Roosevelt Thermal area. Thermal waters of the dry spring, a seep, and the deep reservoir are dilute (ionic strength 0.1 to 0.2) sodium chloride brines. Spring deposits consist of siliceous sinter and manor sulfur. Alluvium is cemented by sinter and altered in varying degrees by hot, acid-sulfate water to opal and alunite at the surface, grading successively to alunite-kaolinite, alunite-kaolinite-montmorillonite, and muscovite-pyrite within 60 m of the surface. Observed alteration and water chemistry are consistent with a model in which hot aqueous solutions containing H{sub 2}S and sulfate convectively rise along major fractures. Hydrogen sulfide oxides to sulfate near the surface decreasing the pH and causes alunite to form. Opal precipitates as the solutions cool. Kaolinite, muscovite, and K-feldspar are formed in sequence, as the thermal water percolated downward and hydrogen ion and sulfate are consumed.« less

  • ;
    On the western edge of the geothermal field, three deep holes have been drilled that are very hot but mostly dry. Two of them (Phillips 9-1 and Acord 1-26 wells) have been studied by Los Alamos National Laboratory for the Hot Dry Rock (HDR) resources evaluation program. A review of data and recommendations have been formulated to evaluate the HDR geothermal potential at Roosevelt. The present report is directed toward the study of the shallow aquifer of the Milford Valley to determine if the local groundwater would be suitable for use as make-up water in an HDR system. This investigationmore » is the result of a cooperative agreement between Los Alamos and Phillips Petroleum Co., formerly the main operator of the Roosevelt Hot Springs Unit. The presence of these hot dry wells and the similar setting of the Roosevelt area to the prototype HDR site at Fenton Hill, New Mexico, make Roosevelt a very good candidate site for creation of another HDR geothermal system. This investigation has two main objectives: to assess the water geochemistry of the valley aquifer, to determine possible problems in future make-up water use, such as scaling or corrosion in the wells and surface piping, and to assess the hydrogeology of the shallow groundwaters above the HDR zone, to characterize the physical properties of the aquifer. These two objectives are linked by the fact that the valley aquifer is naturally contaminated by geothermal fluids leaking out of the hydrothermal reservoir. In an arid region where good-quality fresh water is needed for public water supply and irrigation, nonpotable waters would be ideal for an industrial use such as injection into an HDR energy extraction system. 50 refs., 10 figs., 10 tabs.« less

  • ;
    Identification and elemental concentrations of indigenous soil and plant systems found on the Roosevelt Hot Spring KGRA are described. Twenty-three different soils and five separate plant communities are geographically mapped and identified. One hundred forty-seven plant species were identified. Forbs, shrubs, and grasses are represented by 58, 53, and 36 species respectively. Three sites, each measuring 25 hectares, were selected for long-term vegetative assessment. At these locations a permanent enclosure measuring 24.4 meters x 24.4 meters was constructed to assess long-term effects of livestock grazing. Biomass, plant species, percentage composition, ground cover and livestock carrying capacities were determined at eachmore » site. Surface soils and Artemisia tridentata leaf tissue were collected for elemental analysis.« less