Technology Focus: Geothermal Energy (March 2025)

Over the past century, the oil and gas industry has been at the forefront of advancements in subsurface engineering, drilling, and reservoir management. These innovations, developed to optimize hydrocarbon recovery, are now being adapted to unlock the vast potential of geothermal energy. Geothermal systems, which rely on extracting heat from deep within the Earth, face many of the same technical challenges that oil and gas operators have tackled for decades. Geothermal development can be advanced efficiently and economically by applying proven oil and gas technologies. This feature reviews three studies that explore less-obvious ways in which oil and gas expertise could advance geothermal energy development. These examples demonstrate the practical overlap between the industries and identify opportunities to repurpose tools, knowledge, and infrastructure for geothermal operations. The first study investigates the use of supercritical CO2 (SCCO2) as a working fluid for geothermal energy extraction in depleted deep heavy oil reservoirs. Findings from this study suggest that this approach could provide an efficient mechanism for heat extraction and enhances hydrocarbon recovery from the reservoir. Simulations and experimental data revealed larger oil-recovery and heat-utilization efficiencies when using SCCO2. Asphaltene precipitation and permeability loss were identified as possible challenges with the approach. However, the study demonstrates the dual value of thermal energy extraction and hydrocarbon production in a bid to extend the utility of mature reservoirs. The second study evaluates the feasibility of converting existing hydrocarbon wells into geothermal district-heating assets. Focusing on case studies in Italian hydrocarbon fields, the researchers assessed the technical and economic potential of repurposing wells to meet local residential heating demands. The findings highlight that retrofitting hydrocarbon wells significantly lowers capital expenditures while mitigating mining risks. Although operational challenges such as the need for large pump-energy requirements exist, the study demonstrates how existing infrastructure can be effectively repurposed, thus offering an approach to extract additional value from hydrocarbon assets. The third study addresses the critical issue of drilling efficiency in high-temperature rock formations, with findings supported by experimental work conducted in 2021–22. The researchers conducted high-pressure/high-temperature simulations to evaluate how thermal effects influence rock drilling. They found that rapid cooling of the rock at the drill bit substantially enhanced the rate of penetration, with improvements ranging from 59 to 197% depending on the bit type and the temperature differential between the hot dry rock and the drilling fluid delivered to the bit face. These findings provide actionable approaches that could enhance drilling efficiency in geothermal wells, thereby reducing both operational time and costs. These studies collectively highlight oil and gas technologies’ contributions to geothermal energy development. Such a synergy represents an opportunity to maximize the value of oil and gas knowledge and infrastructure in addressing the growing interest in geothermal applications, ensuring that both industries remain central to meeting energy needs reliably and efficiently. Recommended additional reading at OnePetro: www.onepetro.org. OTC 34901 - Energy Recovery From Geothermal Reservoirs in the Baram Basin, Sarawak: A Numerical Reservoir Simulation Approach With CO2 Utilization by M. Bataee, Curtin University Malaysia, et al. SPE 220012 - Geothermal Energy Recovery for Urban Heating Applications: Risks and Rewards by Meng Cao, The University of Texas at Austin, et al. SPE 222117 - Revolutionizing Drilling Through Natural Fractures: Leveraging Causal Artificial Intelligence and Real-Time Feed-Zone Monitoring by Syed Aaquib Hussain, SLB, et al. OTC 35140 - Review of Offshore Geothermal Projects: Past Projects and Current Ideas by J. Batir, Teverra, et al.