| Title | A Rigorous Design Approach for Superhot Rock Wells |
|---|---|
| Authors | P. Jammer, P. V. Suryanarayana, S. M. Rahman |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Superhot rock (SHR) resources (>374°C) are of increasing interest for commercially viable and scalable geothermal energy extraction, with many innovative technologies being developed and tested. Chief among the challenges that SHR entails is well construction and integrity—19 attempts have been made worldwide, and in virtually all, the wells failed prematurely. This underlines the need for a rigorous basis of design for these wells. The authors describe in detail a comprehensive approach, combining reliability-based design (RBD), low cycle fatigue (LCF), and thermomechanically managed tubular installation. In SHR wells, design dictating loads are typically stimulation loading (high pressure, low temperature) and geothermal production (high temperature). Stimulation drives the design of the deeper section with its high pressures, necessitating high strength materials; production drives the design of the shallower sections with its large temperature changes, necessitating highly ductile materials. To address both requirements, the production string is designed with a material crossover, applying an RBD approach for high strength materials and a post-yield design basis (utilizing DFDI and Critical Strain in the LCF approach) for ductile materials. Consideration is also given to managing casing pre-compression and installation temperature, annular pressure buildup, “cold” collapse and connection selection. A clear illustration of this approach is presented through a case study (400°C) designed for dual service (injection/production). In conclusion, it is believed the presented approach will deliver well designs that maintain their integrity through the intended service life of the well, thus allowing SHR reservoirs to be created and energy successfully extracted. |