Modified cyclic SCCO2 injection for energy recovery and thermal breakthrough mitigation in Saskatchewan geothermal reservoirs

Abstract

Geothermal energy is a promising solution to meet the increasing global energy demand while mitigate climate change. In recent years, the utilization of carbon dioxide (CO₂), especially supercritical CO₂ (SCCO₂), for geothermal energy recovery has attracted increasing attention. This study introduces and simulates a modified cyclic SCCO₂ injection method for geothermal energy recovery, marking the first exploration of its kind. We analyzed the SCCO₂ injection process under various well patterns and injection modes, comparing the cumulative energy recovery performance of cyclic and continuous injection across different models. Our findings revealed that the original reservoir dominates the initial energy production until the SCCO₂ breakthrough. After the breakthrough, cyclic injection should be utilized to enhance energy production, with higher heat extraction efficiency and the mitigation of the thermal breakthrough effect. In addition, our findings suggest that an optimal combination of cyclic and continuous injection can leverage the advantages of both strategies. Through further optimization, modified cyclic SCCO₂ injection method enhances energy production, achieving up to a 59% improvement in cumulative energy production (4.155E14J) and a 200% increase in NPV ($600,000) compared to baseline scenarios, with higher heat extraction efficiency and mitigation of thermal breakthrough effects.