Publications Details

Chloride-based Wireline Tool for Measuring Fracture Inflow in Enhanced Geothermal Systems (EGS) Wells: Field Deployment Updates

Schneider, Melanie B.; Sausan, Sarah; Hartung, Marshall; Horne, Roland; Cochrane, Alfred H.; Su, Jiann-Cherng; Wright, Andrew A.; Myers, Taylor A.; Pope, Joseph S.; Tafoya, Joshua J.

This paper presents the ongoing development of a chloride-based wireline tool designed to detect and quantify inflows from feed zones in geothermal wells. The tool aims to characterize stimulation events in EGS wells at Utah FORGE (Frontier Observatory for Research in Geothermal Energy) and other EGS sites. Successful development of the chloride tool would greatly improve production monitoring of the fractures and enable proactive prescription of additional stimulations over the life of the field, thus helping to improve EGS commercial feasibility. The recent developments of the chloride tool have focused on preparing for and conducting the field deployment at the Utah FORGE site. The field-scale tool assembly features a FORGE sensor package housing the Ion Selective Electrode (ISE), a pH electrode, and a reference electrode, as well as a Mitco PTS sensor package for secondary downhole measurements. A high-temperature logging tool has been developed and tested to capture and transmit data from the chemical sensors to the surface through a 7-conductor wireline cable. Alongside the development of the field-scale tool, flow experiments were carried out in the artificial well system at the Stanford Geothermal Lab. These experiments provided crucial insights into how the chemical tool responds to different variables, including the chloride concentration in the feed zone, its vertical positioning relative to the feed zone, and the presence of other chemical species in the feed zone fluid. The results highlight the tool's sensitivity to various parameters, underscoring the potential of using chloride concentration measurements as a method for inferring feed zone inflow rates in geothermal wells. The tool was successfully deployed at the Utah FORGE site using a wireline truck in the vertical well 58-32 and the directional production well 16B(78)-32.