Stanford Geothermal WorkshopFebruary 9-11, 2026

This study investigates the thermal behavior of an Enhanced Geothermal System (EGS) well during production and wireline intervention, with emphasis on how wellbore heating influences the feasibility and safety of wireline operations. A major challenge is maintaining surface temperatures within limits to ensure compatibility with Pressure Control Equipment (PCE) and wireline systems under high-temperature conditions. A thermal model was developed using real temperature data from Utah 16B(78)-32 well up to 6,000 ft, supplemented by two artificial high-temperature scenarios (bottom-hole temperatures of 250 °C and 300 °C) for depths between 6,000 and 18,000 ft. The axisymmetric model incorporates heat transfer through fluid convection and solid conduction in both axial and radial directions. The simulation consisted of five phases: establishing initial conditions with real and artificial temperature profiles; production at 2,000 gal/min; a one-hour shut-in; tempering with 400 gal/min of 25 °C water for two hours; and a 24-hour wireline operation period, during which surface temperature was targeted to remain below 80 °C to prevent flashing and steam formation with a 20 °C margin. Results reveal significant heat retention in the formation during production, leading to reheating during wireline operations despite prior tempering. For the 250 °C case, proper tempering maintained surface temperatures below 80 °C for 24 hours, enabling safe wireline or coiled tubing work. In contrast, for the 300 °C case, surface temperature rose to 86.2 °C after 24 hours, slightly exceeding the limit. This work underscores the importance of surface temperature control and highlights the need for practical thermal management strategies to ensure safe and efficient geothermal wireline operations. The developed model serves as a predictive tool for assessing thermal behavior under various operational scenarios, supporting proactive planning and minimizing intervention downtime.

Topic: Modeling