In Geologic Thermal Energy Storage (GeoTES) systems subsurface reservoir forms a thermal battery, storing heated or chilled brine using excess energy generated by wind or solar systems. Stored brine can then be produced for power generation or for district heating and cooling. High permeability sedimentary reservoirs can serve as long-duration and large capacity storage batteries due to their high porosity and large extent. Long-term sustainability of GeoTES systems depends on the response of the rock formation to coupled Thermo-Hydro-Mechanical (THM) loads induced by injection and production operations. If operational parameters are not optimized, with data unique to reservoir formations, alteration of mechanical and flow parameters in the near wellbore behavior, can lead to reduced system output. These issues could include mechanical degradation, fines mobilization, flow channeling and permeability anomalies. In this study we present an integrated subsurface characterization and modeling study to simulate THM behavior of a GeoTES system in shallow, high porosity sedimentary formations from the US Texas Gulf Coast. Our 2D/3D modeling approach incorporates THM coupled solutions to simulate flow through porous media while considering heat transfer and damage mechanics. We collect and use data from a planned demonstration site to characterize THM properties of target formations representative of a GeoTES system. We integrate operational parameters and formation characteristics within a suite of models and conduct sensitivity analysis. Results show that THM loading conditions can lead to near wellbore formation alteration. Operational parameters, unique to high porosity-weakly consolidated formations can be optimized to control near wellbore formation response to injection and to minimize potential integrity and injectivity issues. In this sense, integrated characterization and modeling workflows provide constraints on wellbore operability limits.

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