THMC Modeling for CO₂ Geological Storage: Advances, Challenges, and Prospects

CO₂ geological storage (CGS) is an important way to reach carbon neutrality. Its long-term safety and effectiveness depend on the interplay of thermal, hydraulic, mechanical, and chemical (THMC) processes. However, contemporary research frequently examines discrete processes or particular geological contexts, resulting in a fragmented understanding of THMC interactions and the absence of a unified framework for multiphysics simulation. This paper presents the first comprehensive review of the application landscape of THMC coupling in CGS. It elucidates the fundamental processes of each physical field and their interacting mechanisms, spanning from two- to four-field coupling. It also looks at the pros and cons of common numerical tactics, computational methodologies, and software platforms, as well as how useful they are. It looks at the most important uses of THMC models in site screening, wellbore integrity evaluation, and storage evolution forecasts using common situations such as deep saline aquifers and depleted oil and gas reservoirs. This paper talks about current problems, such as computing efficiency, parameter uncertainty, and lack of validation. It does this by suggesting eight development ideas, such as using intelligent algorithms, multiscale modeling, data assimilation, and standardized platforms. This evaluation encourages a better understanding of how things work, better engineering techniques, and the growth of CGS into a safer, more efficient, and larger-scale application.