The Correlation of Noncondensible Gas and Chloride in Steam at The Geysers

Abstract

Noncondensable gas and hydrogen chloride (HC1) concentrations correlate positively in steam from two areas of the Geysers, Unit 15 and Coldwater Creek, which produce corrosive HC1 bearing steam. Unit 15 has been producing for over 10 years, and the production of HC1 bearing steam is relatively recent. Coldwater Creek, which has just begun production, produced HC1 bearing steam from initial flow tests. According to basic chemistry and models of the reservoir, there are common reservoir characteristics which generate HC1 and relatively high noncondensable gases in steam form vapor dominated systems such as the Geysers. These are: a) a relatively hot saline source such as a deeper brine, irreducible water or connate pore water, b) a relatively dry or poorly connected shallow, originally condensate saturated, 240-250°C, "typical" reservoir zone. This zone may be dried out by production as in the case of Unit 15 removing the HC1 scrubbing and upon vaporization its gas diluting capabilities.