Energy extraction from fractured geothermal reservoirs in low-permeability crystalline rock

Journal Article · Mon Aug 10 04:00:00 EDT 1981 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JB086iB08p07145· OSTI ID:5911487

Murphy, H D; Tester, J W; Grigsby, C O; Potter, R M

Two hot dry geothermal energy reservoris were created by hydraulic fracturing of Precambrian granetic rock on the west flank of the Valles Caldera, a dormant volcanic complex, in the Jemez Mountains of northern New Mexico. Heat was extracted in a closed-loop mode of operation, injecting water into one well and extracting the heated water from a separate production well. The first reservior was produced by fracturing the injection well at a depth of 2.75 km, where the indigenous rock temperature was 185 /sup 0/C. The relatively rapid decline in temperature of the water produced from the first reservoir, 100 /sup 0/C in 74 days, indicated an effective fracture radius of about 60 m with an average thermal power extracted of 4 MW. A second, larger reservoir was created by refracturing the injection well 180 m deeper. Downhole measurements of water temperature at the reservior outlet as well as temperatures inferred from chemical geothermometry showed that the thermal decline of this reservoir was negligible; the effective heat transfer area of the new reservoir must be at least 45,000 m/sup 2/, nearly 6 times larger than the first reservior. In addition, residence time studies employing visible dye tracers indicated that the mean volume of the second reservoir is 9 times larger. Other measurements showed that flow impedances were low and that downhole water losses from these reservoirs should be manageable. The geochemistry of the produced water was essentially benign with no scaling problems apparent. Moreover, the level of induced seismic activity was insignificantly small.

• Research Organization: Los Alamos National Laboratory, University of California, Los Alamos, New Mexico 87545
• OSTI ID: 5911487
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 86:B8; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150201* -- Geology & Hydrology of Geothermal Systems-- USA-- (-1989)
CHEMICAL COMPOSITION
COMMINUTION
DRILLING
ENERGY SYSTEMS
ENERGY TRANSFER
FRACTURING
GEOTHERMAL SYSTEMS
GEOTHERMOMETRY
GRANITES
HEAT TRANSFER
HOT-DRY-ROCK SYSTEMS
HYDRAULIC FRACTURING
IGNEOUS ROCKS
INJECTION WELLS
NEW MEXICO
NORTH AMERICA
PLUTONIC ROCKS
ROCKS
SEISMICITY
SOUTHWEST REGION
USA
WELL DRILLING
WELLS