A Tracer Test Using Ethanol as a Two-Phase Tracer and 2-Naphthalene Sulfonate as a Liquid-Phase Tracer at the Coso Geothermal Field

摘要

A tracer test was conducted at the Coso geothermal field inorder to characterize the flow patterns of fluid injected into well 68-20RD. A conservative liquid phase tracer, 2-naphthalene sulfonate, and a two-phase tracer, ethanol, were injected into well 68-20RD. Surrounding production wells were sampled over the subsequent 125 days and analyzed for the two tracers. The liquid-phase tracer showed negligible returns, whereas the two-phase tracer showed strong and immediate returns to two wells and slower but significant returns to two additional wells. These results demonstrate the efficacy of the simultaneous use of liquid-phase and two-phase tracers in fluid-depleted geothermal fields.