Impact of Well Placement on Heat Recovery in Enhanced Geothermal Systems

Abstract

In Enhanced Geothermal Systems (EGS), the placement of producers relative to injectors can play a very important role in controlling fluid flow patterns, fracture connectivity, and overall energy recovery. Improper placement can result in rapid thermal breakthroughs or reduced heat sweep efficiency. This study aims to (1) investigate how the relative angular alignment of the injector-producer pair influences heat recovery, and (2) provide quantitative design strategies for optimizing well placement to enhance long-term geothermal performance. A fully coupled reservoir-fracture-well simulator that models multi-phase flow, geomechanics, and thermal effects is employed to simulate the fluid circulation process and examine fracture propagation in EGS. It simulates the propagation, opening, and closing of propped fractures under the influence of thermo-poro-elastic stress. The geothermal heat recovery was simulated for different well placements. Changes in flow patterns and fracture geometry over time were analyzed, providing insights into fracture dynamics during geothermal recovery and their impact on overall efficiency. Simulation results demonstrate that well spacing and placement strongly influence heat recovery. Although late-time thermal power converges across all cases, cumulative thermal energy increases significantly with production-well elevation. Larger positive angles enhance buoyancy-driven circulation and sustain heat extraction over longer timescales. These findings highlight the trade-offs in fracture utilization and thermal sustainability, underscoring the importance of carefully selecting well placement strategies in EGS.