Deep geological carbon dioxide injection induces coupled thermal, hydraulic, and mechanical processes that critically influence caprock integrity and long-term storage security in saline aquifers. Although thermo-hydro-mechanical (THM) coupling has been widely addressed in prior studies, most existing simulation platforms such as TOUGH-FLAC, OpenGeoSys, and commercial finite element tools are constrained by rigid solver architectures, limited equation customization, and external dependencies, limiting their applicability for flexible, research-oriented investigations. Addressing this limitation, the present work develops a fully self-contained, MATLAB-native THM simulation framework that integrates transient Darcy flow, advective–conductive heat transport, and linear poroelastic stress analysis within a sequentially synchronized, modular solver loop. The novelty of this approach lies in its symbolic partial differential equation assembly, adaptive meshing, and dynamic update of thermophysical properties including density, viscosity, heat capacity, and thermal conductivity, enabling high-fidelity modeling without external software coupling. Simulation results reveal that pressure-driven flow advances more rapidly than thermal diffusion, creating temporally decoupled stress zones wherein caprock deformation is governed primarily by pore pressure, with thermal contraction effects modulating stress localization. The solver captures detailed stress anisotropy and shear stress amplification, and identifies mechanically vulnerable regions through effective stress ratio mapping. Furthermore, explicit injection rate sensitivity analysis links operational parameters to thermal front dynamics and mechanical response, offering actionable insights for optimizing injection protocols. These findings are directly applicable to the design, risk assessment, and operational control of carbon sequestration projects, enhancing predictive accuracy in caprock integrity evaluations.
Emani et al. (Wed,) studied this question.