| Abstract |
The growing demand for low-carbon heat in Saudi Arabia highlights the untapped potential of low- to medium-enthalpy geothermal resources in sedimentary basins such as the Midyan basin. Optimal field-scale development remains challenged by the complex interplay between subsurface uncertainty, thermal performance, and economic feasibility. This study evaluates the techno‑economic viability of multi-well layout in the water-saturated sedimentary formations of the Midyan Basin along Saudi Arabia’s Red Sea Rift. Multi-well configurations are investigated to effectively sweep heat from a larger rock volume. A 3D fully coupled Darcy‑flow and heat-transfer model is constructed in COMSOL Multiphysics and parameterized using geological data from the Midyan basin, including porosity, permeability, and geothermal gradient. The simulations will consider a 30‑year production period using both brine and supercritical CO₂ as working fluids. An optimization framework is developed to identify optimal well spacing and injection rate to minimize the levelized cost of energy (LCOE). Geological and economic uncertainties are addressed through Monte Carlo sampling, and global Sobol indices are used to rank the influence of key parameters such as permeability, porosity, CAPEX, and OPEX on both thermal output and economic performance. The results highlight optimal well layout configurations that maximize cumulative heat recovery while ensuring economic feasibility. This integrated workflow links subsurface variability to project economics, enabling the optimization of multi‑well geothermal systems in sedimentary formations and informing investment decisions for geothermal development in the Midyan Basin and other sedimentary basins. |