This paper presents the first successful drilling and completion of a twinned geothermal well pair in a 330 °C volcanic reservoir, achieving a step-change in performance and reliability. The project demonstrated precise placement of a new production wellbore (55A-29) within 2 m of its planned trajectory and 90 m of an existing well, enabling a controlled hydraulic connection under extreme conditions. Through system-level integration of optimized BHA design, thermal management, and operational discipline, the campaign reduced on-bottom drilling time by 45% (from 40 to 22 days) and increased the average rate of penetration (ROP) by 150–300% compared to offset wells. Critically, over 120 cumulative circulating hours above 300 °C were achieved with zero downhole motor or MWD failures. The efficiencies achieved indicate that much deeper geothermal wells to access greater than 300 °C resources at other locations can be drilled reliably and economically with conventional tools. The results provide a scalable pathway toward superhot ( greater than 400 °C) geothermal resource development.

Press the Back button in your browser, or search again.

Copyright 2026, Stanford Geothermal Program: Readers who download papers from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the original publisher.