Co-processing of energy storage and CO2 sequestration in saline aquifers

Abstract

Underground aquifer compressed gas energy storage represents a promising frontier for large-scale peak shaving and integrated CO2 sequestration. This study employs the CMG-GEM compositional simulator to develop a numerical model of an anticlinal aquifer, investigating cyclic injection-production dynamics. Sensitivity analyses were conducted on reservoir porosity and formation water NaCl concentration to evaluate their impacts on bottom-hole pressure (BHP), temperature, gas saturation, and CO2 storage capacity. Results indicate that increasing porosity significantly mitigates BHP buildup while enhancing CO2 solubility trapping, achieving a peak storage of 382,911.7 mol. Conversely, varying NaCl concentrations negligibly affect BHP but induced notable bottom-hole temperature variations due to altered thermophysical properties. These findings provide insights into the multi-physics coupling mechanisms governing subsurface gas behavior, providing a theoretical basis for short-term operational assessment and optimization of aquifer-based energy storage systems.