Monitoring Criteria on Transition of Well Discharge from Two-phase to Dry Steam

Abstract

Two-phase geothermal wells sometimes turn to produce dry superheated steam. We have introduced a quantitative monitoring criterion to identify potential two-phase wells which may become superheated. We first estimated enthalpy gain ratio from reservoir to well head based on data of some production wells. Then, we estimated a quality of two-phase fluid at well head from residual water saturation at the far end of in-flow region, using the enthalpy gain ratio. Based on monitoring results of production performance of some wells, we found that this criterion is reasonable and the transition from two-phase production to superheated steam does not occur gradually but relatively suddenly.