Technical and Economic Evaluation of a Geothermal Field in a Sedimentary Basin on the Texas Gulf Coast

Abstract

Geothermal energy is an appealing source of baseload renewable energy capable of supplying constant energy regardless of seasonal and other environmental factors. Benefiting from subsurface natural heat anomalies, geothermal energy projects have been developed primarily on igneous and metamorphic environments where temperature gradients are elevated near the surface. Hard rock combined with high temperatures and a corrosive environment makes geothermal drilling difficult and expensive. However, the access to hot reservoirs is not limited to igneous and metamorphic environments. Fields with downhole temperatures of 150C and above are present in reservoirs 3 to 4 km depth in sedimentary basins in the US. Sedimentary environments have the advantage of large quantities of existing subsurface datasets and lower cost to drill. Additionally, the porosity and permeability in sedimentary basins are more favorable than traditional geothermal reservoirs, allowing for improved flow potential and heat extraction. In this paper, a technical, economic evaluation is performed to ascertain the potential geothermal development in a sedimentary field in the Gulf Coast area in Texas. Various reservoir simulations with different wells configurations were analyzed. Furthermore, the use of existing oil and gas wells, combined with new vertical and horizontal wells, is evaluated. A sensitivity analysis indicates that permeability and fracture density affect the heating extraction rate. Also, the variation in the wells' position and configuration affect the energy production. Finally, we conclude that the project of heat extraction for power generation in the area evaluated is technically feasible.