Design And Construction of A Novel Drilling Rig For The Investigation of Hard Rock Drilling for Super-Hot Enhanced Geothermal System Development

Abstract

The pursuit of sustainable energy solutions in the face of increasing global demand has fueled interest in super-hot Enhanced Geothermal Systems (EGS). These systems tap into vast, recoverable geothermal energy potential capable of meeting humanity's long-term heat and electricity needs. The traditional geothermal power plants, relying on conventional flash steam or binary cycle technology, demonstrate limited efficiency and incur high capital costs due to the low energy density of available temperatures. Nevertheless, drilling operations targeting super-hot geothermal reservoirs encounter formidable challenges, particularly in igneous basins. Existing drilling technologies and practices often prove inadequate for such harsh conditions, necessitating advancements in drilling methodologies and equipment. This thesis presents a novel lab-scale drilling rig designed to facilitate the testing and development of technologies for geothermal drilling. Rig construction involved meticulous attention to structural integrity and compatibility with high-temperature test requirements. Integration of sensors facilitated real-time data acquisition for performance analysis. Experimental drilling tests were conducted on sandstone and granite samples, exploring the effects of temperature on drilling rates and bit performance. The data were analyzed to evaluate the drilling efficiency and the impact of temperature on rock strength. Additionally, techno-economic evaluation of the super-hot EGS was carried out, considering factors such as the well cost and resource temperature to investigate the impact of temperature and drilling speed on the levelized cost of electricity. Historical drilling data were used to generate time-to-hit-temperature, cost-to-hit-temperature, and favorability maps for geothermal system development across the United States. The findings of this thesis will contribute to the advancement of drilling technologies and provide insights for strategic decision-making in geothermal resource development.