This report reviews state-of-the-art deep geothermal drilling and well-construction technologies, identifies existing technology gaps, and suggests strategies to overcome these gaps. The technologies include conventional drill bits, hybrid conventional drill bits, direct energy drilling systems, high-temperature downhole tools, insulated drill pipe, low-heat coefficient coatings, supercritical CO2, drilling fluid, drilling muds, and mud coolers. Each technology is assessed and given a technology readiness level between 1-9, from theoretical to commercially scalable.
The report focuses on the technology frontier for drilling and well construction in the context of the superhot rock (SHR) geothermal energy systems: the production of renewable, baseload electricity by circulating water in deep (>5 km) rock that is more than >374˚C. While the Cascade Institute's Ultradeep Geothermal Program covers a broader range of next-generation geothermal systems (including lower-temperature systems), the technology assessment in this report is relevant to all ultradeep geothermal projects.
