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Title: Hot Dry Rock energy annual report fiscal year 1992

Technical Report ·
DOI:https://doi.org/10.2172/6443299· OSTI ID:6443299

Hot Dry Rock technology took a giant leap forward this year as the long-awaited long-term flow test (LTFT) of the Phase II HDR reservoir at Fenton Hill got underway. Energy was produced on a twenty-four hour a day basis for a continuous period of nearly four months of steady-state testing. Hot water was brought to the surface at 90-100 gallons per minute (gpm) with temperatures of 180[degrees]C (356[degrees]F) and higher. During that time, the HDR plant achieved an on-line record of 98.8%. Surface temperature measurements and temperature logging deep within the wellbore confirmed that no decline in the average temperature of fluid produced from the reservoir occurred. Tracer experiments indicated that flow paths within the reservoir were undergoing continuous change during the test. Remarkably, it appeared that longer flow paths carried a larger proportion of the flow as the test proceeded, while more direct fluid pathways disappeared or carried a significantly reduced flow. In sum, access to hot rock appeared to improve over the span of the test. Water losses during the test averaged 10-12% and showed a slow long-term decline. These results confirmed what had been previously discovered in static pressurization testing: Water consumption declines significantly during extended operation of an HDR reservoir. In combination with a recent demonstration by the Japanese that water losses can be greatly reduced by the proper placement of multiple production wells, the recent results at Fenton Hill have effectively demonstrated that excessive water consumption should not be an issue for a properly engineered HDR facility at a well chosen site.

Research Organization:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE; USDOE, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
6443299
Report Number(s):
LA-UR-93-1678; ON: DE93014452
Country of Publication:
United States
Language:
English