Self-potential Monitoring around Wells in Mutnovsky Geothermal Field, Kamchatka.

Abstract

We carried out self-potential (SP) monitoring around geothermal wells during flow tests in September 1995 at Mutnovsky field in southern part of Kamchatka peninsula. SP variation of 80 mV across a 200 m dipole was observed during the flow test of well 49; potential near the well increased rapidly after turning on the discharge and recovered to the original level after shutting the well. The observed variation seems to be associated with liquid and vapor two-phase flow induced in the reservoir, and can be well explained by a proposed electrokinetic model. Although the vapor phase can not move charge, the present results indicate that the streaming current is not reduced for two-phase flow so long as the liquid phase flows.