Summary of a Heat Flow Mapping Project at The Geysers Geothermal Field, California

Abstract

Temperature depth data from 70 of 187 temperature gradient hole sin the vicinity of the Geysers Geothermal field were terrain corrected. The terrain corrected data provided a basis for constructing a temperature gradient map and heat flow map. Cutting samples from 16 deep production wells were analyzed for thermal conductivity. From these samples, the mean thermal conductivity for serpentinized ultramafic rock, greenstone, and graywacks were determined. the temperature gradient and heat flow maps show that the Geysers Geothermal field is part of a vary large northwest trending anomaly; the commercially productive portion of the field may be 100 km2 in area. the rate of heat energy discharged through the surface by thermal conduction is 1.79 x 10/9 MJ per year, while the net heat energy loss from commercial production for the year 1983 is estimated at 180.14 x 10/9 MJ.