Enhancing Energy Output in Geo-Pressured Reservoirs: A Metaheuristic Approach to Optimize Enthalpy Production

Abstract As the demand for sustainable and reliable energy rises, the urgency of discovering new energy sources is also increasing. Although fossil fuels have been a major contributor to the world's energy, their sources are diminishing. Renewable energy sources such as geothermal energy have become the focus and a possible alternative for the fast-diminishing fossil fuel sources. Many researchers have studied the production rate and the quantity of energy generated. These studies have focused on enhancing energy produced through simulations and machine learning analysis through cold water and CO2 injection. These procedures have contributed to improving the energy production from geo-pressured reservoirs but have not focused on enhancing the enthalpy of the heat generated within the reservoir. This has resulted in limited knowledge of controlling injection constraints to enhance the enthalpy generated by a geo-pressured reservoir. This study focused on coupling geothermal simulation with metaheuristic optimisation algorithms to optimise the produced enthalpy of a geothermal reservoir and enhance the quantity of energy produced. A dual permeability geothermal reservoir was modelled to investigate the efficiency of enhanced geothermal systems. The base case revealed a rapid pressure decline from 25,000 kPa to <14,000 kPa and diminishing thermal efficiency due to limited fluid recharge. Introducing injectors activated via a pressure trigger of <24,000 kPa reduced pressure decline by 60%, sustaining reservoir performance and boosting cumulative enthalpy production by 45.75% compared to the base case. Sensitivity analysis employing a Radial Basis Function Neural Network proxy model identified fracture spacing as the dominant parameter (98% contribution), governing fracture-matrix heat exchange, while matrix porosity (1.1%) and permeability anisotropy (0.91%) had secondary impacts. Rock thermal properties exhibited negligible influence, underscoring the convective nature of heat transfer in such systems. The findings highlight the critical role of pressure maintenance and fracture network optimization in enhancing long-term geothermal energy output.