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U.S. Department of Energy
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EVAULATION OF THE MAKUSHIN GEOTHERMAL RESERVOIR, UNALASKA ISLAND

Conference ·
OSTI ID:892538
Analysis of an extended flow test of well ST-1 on the flanks of Makushin Volcano indicates an extensive, water-dominated, naturally fractured reservoir. The reservoir appears to be capable of delivering extremely large flows when tapped by full-size production wells. A productivity index in excess of 30,000 lb/hr/psi implies a phenomenal permeability-thickness product, in the range of 500,000 to 1,000,000 md-ft. The flowing bottomhole (1,949-foot) temperature of the fluid is 379 F, which is lower than the measured static temperature at that depth (395 F). This phenomenon, coupled with an observed static temperature gradient reversal from the maximum 399 F observed at 1,500 feet, indicates that the reservoir proper is located some distance from the well. presumably it is at a temperature slightly lower than 379 F and communicates with the wellbore via a high conductivity fracture system. A material balance calculation yields an estimate of reserves that are capable of sustaining all of the present power needs of the island (13 {+-} MW peak) with a geothermal power plant for several hundred years. Theoretically, a single large diameter well at the site of ST-1 could satisfy this requirement.
Research Organization:
Unlverslty of Alaska, Fairbanks, AK; Republlc Geothermal, Inc., Santa Fe Sprlngs, CA
Sponsoring Organization:
USDOE
OSTI ID:
892538
Report Number(s):
SGP-TR-84; CONF-850107-37
Country of Publication:
United States
Language:
English