A Geochemical Case History of the HGP-A Well, 1976-1982

Abstract

The Hawaii Geothermal Project Well-A, located on the Island of Hawaii, was completed in 1976 to a depth of 1966 meters. The bottomhole temperature, under shut- in conditions, is and at full discharge is capable of producing about 45,500 of a mixed fluid composed of 48% steam and 52% liquid. The major element chemistry of the fluids suggests that recharge t@the reservoir is largely fresh meteoric water with no more than 10%t o 15%o f the recharge being from sea water. Extensive water-rock equilibration has occured; however neither nor silica geothermometry calculations have been e to yield reasonable reservoi r temperatures. Isotopic data suggest that the circulation rate and residence times of fluids in the reservoir are on the order of a few thousand years. isotopic data also indicate that the heat source forth is reservoir is very young or very large.