Numerical assessment of geothermal heat extraction potential in Geopressured Wilcox reservoir along the Texas Gulf Coast

Deep geopressured reservoirs along the Texas Gulf Coast represent a largely underexplored geothermal resource. This study develops an integrated geological–engineering framework to evaluate the long-term heat extraction potential of the Wilcox Formation using fully coupled non-isothermal reservoir simulation. A three-dimensional faulted geological model was constructed and integrated with petrophysical characterization, conductive heat-loss modeling in the overburden and underburden, and wellbore heat-transfer modeling under realistic operational constraints. Simulations were performed for both water and CO 2 injection scenarios under open-loop conditions over multi-decade production periods. Results indicate that deep Wilcox reservoirs can sustain long-term geothermal production using a conventional injector–producer configuration, with gradual thermal decline controlled primarily by inter-well spacing, permeability, and injection strategy. In the base-case water-injection scenario (400 m well spacing, bulk thermal conductivity 1.8 W/m·K), produced temperature declines from 150 °C to approximately 100 °C over 50 years. Increasing inter-well spacing to 1400 m with up-dip injector placement sustains produced temperatures near 140 °C at 50 years—approximately 40 °C higher than the base case. Increasing bulk thermal conductivity to 3.8 W/m·K reduces long-term thermal decline by approximately 15 °C relative to the base case. Increased formation thermal conductivity improves temperature maintenance by enhancing conductive heat recharge, while higher permeability accelerates thermal breakthrough due to faster cold-front propagation. Well placement relative to structural dip significantly influences production sustainability in faulted systems. CO 2 injection exhibits distinct hydraulic and thermal behavior compared to water, including stronger pressure sensitivity and earlier breakthrough (approximately 3 years) under gas–liquid ratio constraints, with a total temperature decline of approximately 14 °C over 50 years under the evaluated conditions. Although CO 2 does not consistently outperform water as a heat-extraction fluid under the open-loop evaluated conditions, it presents potential advantages when integrated with carbon storage objectives. This work provides a Wilcox-specific, field-scale assessment framework that couples geological structure, thermal boundary effects, and operational constraints, offering a transferable methodology for geothermal feasibility evaluation in deep sedimentary basins.