Twinned at 300°C+: High-Performance Geothermal Drilling — Newberry Case Study

Abstract

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.