PRELIMINARY RESULTS OF GEOCHEMICAL MONITORING AND TRACER TESTS AT THE COVE FORT-SULPHURDALE GEOTHERMAL SYSTEM, UTAH

Abstract

The Cove Fort-Sulphurdale geothermal system pro-duces both dry steam from a shallow parasitic vapor cap and liquid from the underlying liquid-dominated resource. Samples of the steam and liquid indicate that their compositions have remained stable since production began in 1985 but that the field experi-enced a transient pulse of increased gas shortly after injection was initiated in mid 1996. Liquid and va-por-phase tracers were injected into the reservoir in January, 1999. Steam containing R-134a, which was used to trace the movement of the vapor phase, was observed in the production wells after 2 weeks. However, as of December, 1999, tracer concentra-tions were still increasing. The shape of the tracer return curves suggests that the steam cap taps a small fraction of the injectate plume near the injection well, and that the majority of the tracer is still traveling slowly in the liquid phase. Fluorescein was used to trace the liquid that was injected. To date, no fluo-rescein has been observed in samples from the well that discharges liquid water.