Browsing by Author "Lu, Yue"

Now showing 1 - 1 of 1
  • Thumbnail Image
    ItemOpen Access
    Numerical simulation of geothermal energy production in the Estevan area using water and CO2 as working fluids
    (Faculty of Graduate Studies and Research, University of Regina, 2024-05) Lu, Yue; Jia, Na (Jenna); Zhao, Gang (Gary); Shirif, Ezeddin
    Geothermal energy is a promising and clean renewable resource that is widely accessible around the world (Avci, A.C., et al., 2020). The city of Estevan is proven to possess some geothermal qualities which can be utilized for heating and electrical power generation (Jacek Majorowicz et al., 2021). Water is the most common working fluid to extract geothermal energy; However, water-based geothermal systems may cause issues, such as water loss and induced seismicity. Recently, CO2 has attracted more interest as an alternative injectant to explore geothermal energy because of its high mobility, thermal properties and the additional benefits of CO2 sequestration. In this study, based on the geological and reservoir information in Estevan, a realistic base numerical model is established using Computer Modelling Group (CMG) software to simulate the geothermal energy exploitation process via injecting water and CO2. Results demonstrate that the CO2 Plume Geothermal (CPG) system is more efficient than water-based geothermal systems under specified conditions. The heat extraction rate of the CPG system is 2.5 times that of the water-based geothermal system. In addition, the co-axial closed-loop method for geothermal energy extraction is also simulated in this study. Compared with open loop geothermal energy recovery methods, closed-loop geothermal systems are not significantly affected by the flow of reservoir fluids or permeability variation because the reservoir temperature maintains relatively stable. This study simulates a co-axial closed-loop system to extract geothermal energy in the Estevan area and compares the obtained results with the base open-loop model. The results indicated that an open-loop system has better thermal recovery performance because the associated heat transfer processes includes heat conduction and convection, while for a closed-loop geothermal system, heat conduction is the major mechanism for heat transfer. However, the closed-loop method avoids the direct interaction between the working fluid and surrounding formation and minimizes the induced seismicity, which results in less environmental disturbance, and could provide more stable subsurface heat generation. To conclude, the results and conclusions obtained in this study provide a deeper understanding of optimal designs and feasibility investigations of various production methods for CPG and water-based systems in Estevan.