The Recovery of Injected Water as Steam at The Geysers

Abstract

The stable isotopes of hydrogen and oxygen have been used as tracers to track the movement of injected water within UNOCAL NEC Thermal leases at the Geysers, and also used to estimate the mass of injectate recovered for the period 1983-1988. Cooling tower condensate has been injected into the Geysers reservoir since 1969 and that has been supplemented by river waters since 19880. To estimate the contribution of flashed injectate in the produced steam, two methods of calculation were employed: one (R-C) assumed that the produced steam was a mixture of original reservoir steam and flashed condensate only and the other (R-C-M) assumed that a third component, meteoric water, was also present. In 1988 the mass of injectate produced as steam was equivalent to 65% by the R-C method, and 80% by the R-C-M method, of the total mass of water injected that year.