An Element Free Galerkin Simulation of CO₂ Sequestration in Nonhomogeneous Saline Aquifers

The sequestration of carbon dioxide (CO₂) in deep saline aquifers is recognized as a method for decreasing atmospheric greenhouse gas levels. The injection of large quantities of supercritical CO₂ into these deep formations has different degrees of hydraulic, chemical, thermal, and mechanical consequences. The methodology comprises of using the Element Free Galerkin (EFG) modeling technique to study the various effects of CO₂ gas injection. The modeled pressure and CO₂ saturation are essential for assessing the dynamic of aquifer, bottom pressure trends, and its CO₂ storage potential. The coupled approach solves four key equations—system equilibrium, continuity for fluids in porous media, and energy balance—to determine displacement, fluid pressures, and temperature. Here, this research is focused on evaluating the capability of a newly in-house numerical tool for simulation. A coupled thermal-hydro-mechanical model (THM), as an improvement of the isotherm hydromechanical model in their previous work, for geological sequestration of carbon dioxide followed by stress, deformation, and shear-slip failure analyses. The simulation considers the migration of two immiscible fluid phases, CO₂ under supercritical conditions and salt water, within a deformable porous medium in fully coupled THM conditions. A 3D simulation from Salah region of Algeria elucidated crucial geomechanical variables such as displacement, pressure, and temperature, with sensitivity analysis identifying key determinants of outlet. The simulation results showcased the proficiency of the in-house software in CO₂ injection and sequestration. This emphasized the indispensable role of THM analysis in understanding subsurface impacts and mitigating environmental risks related to reservoir pressures and temperatures.