Development of Chloride-based Inflow Detection Measurement in Fractured Enhanced Geothermal Systems (EGS) Wells

Abstract

The ongoing development of chloride-based inflow measurement tool to detect inflow in fractured EGS wells has shown promising results that are presented in this paper. The tool is designed to detect and quantify inflows from individual fractures in EGS wells as a way to characterize the events of stimulations at Utah FORGE (Frontier Observatory for Research in Geothermal Energy) site, and ultimately at other EGS sites. A successful development of such tool will greatly reduce uncertainty in EGS well development and helps in making EGS more commercially attractive.

Confirmations and adjustments to FORGE conditions were performed by modifying the method from two-phase and enthalpy-based to single-phase and flow rate-based. Multidisciplinary data regarding Utah FORGE wells and field configurations were reviewed, particularly the downhole camera survey interpretations, to gather insights on the appropriate experiment designs. Laboratory experiments were conducted in conjunction with numerical simulations to test a wide range of scenarios involving variations in number of feed zones, location of feed zones, and flow rate difference with the wellbore. The experiments and simulations help specify the requirements for physical running of the tool, such as the proximity of the device to the inflow point and the frequency of the measurements. A ruggedized, improved version of the inflow detection tool are being developed to to withstand the environmental conditions at Utah FORGE wells. The acquired data will be compared with other inference techniques such as temperature logging and wireline flow metering for consistency.