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ABSTRACT: Enhanced Geothermal Systems (EGS) offer significant potential for clean energy extraction from hot rock formations. However, maintaining high flow circulation, maximizing heat extraction, and minimizing thermal losses remain major challenges. This study presents a modeling investigation of key physical processes and design considerations for a multistage hydraulically stimulated EGS, utilizing a fully integrated reservoir model. We analyzed the influence of the key fracturing design parameters (injection rates, cluster spacing, well spacing, and fracture conductivity) alongside formation temperature. The findings demonstrate that multistage stimulation within a single cluster enhances well flow performance, delays thermal breakthrough, and enables higher circulating flow rates. Sensitivity analyses reveal a substantial impact of each parameter on EGS performance. Additionally, net present value (NPV) calculations are incorporated to evaluate the economic feasibility of each scenario. This comprehensive study offers valuable insights for appraising and selecting EGS candidates, paving the way for advancements in sustainable and efficient geothermal energy production. 1. INTRODUCTION The increasing demand for clean and sustainable energy has intensified the search for alternative sources. Among these, geothermal energy stands out, harnessing the Earth's internal heat to generate electricity and provide direct heat with very low greenhouse gas emissions (Lu, 2018). Around 11000 MWe of electricity is being produced worldwide from geothermal sources, and the DOE goal is to reach 90.000 MWe by 2050 (Huttrer, 2021). High temperatures of more than 120 C and high flow rates are required for an economic project (Blackwell. D et al., 2011). Conventional geothermal sources are limited, often concentrated in regions with naturally fractured and permeable rock formations to maintain high flow rates (Gyimah et al., 2023). This is where Enhanced Geothermal Systems (EGS) emerge as a game-changer, unlocking the vast potential of hot, impermeable rock formations that were previously inaccessible(Okoroafor et al., 2022). EGS technology creates an artificial flow path by stimulating the underlying rock through hydraulic fracturing (Gyimah. E et al., 2024). Multiple producer and injector wells were drilled with close spacing to circulate the continuously injected fluid. The injected fluid gets its thermal energy from the formation and then produced to the surface (Huenges, 2016). This enhances permeability, allowing fluid circulation and heat extraction. While still in its developmental stages, EGS holds immense promise for significantly expanding geothermal energy's reach and potential (Merzoug, Okoroafor, et al., 2023).
Dehdouh et al. (Sun,) studied this question.