CO2 trapping mechanism in deep saline aquifers under the control of composite geological factors: A numerical case study in China

The increasingly intensifying global climatic change necessitates carbon capture and storage . Reservoir physical properties including porosity, permeability, temperature, and pressure directly control the spatial migration, storage forms, and storage capacity of CO 2 in saline aquifers. Based on China’s first CCS demonstration project in saline aquifers, this study constructed a water-CO 2 -thermal-chemical coupling model for long-term CCS in reservoirs. The results indicate that the deep saline aquifers in the Ordos Basin are favorable for CO 2 mineral trapping, with a mineralization storage amount reaching up to 64.02 % of the total injection amount at 1000 years. Temperature is identified as the most significant factor influencing safe CO 2 mineral trapping under CO 2 injection. The study not only provides valuable insights into the mechanisms of CO 2 trapping but also lays a foundation for optimizing the design of ongoing CCS projects and evaluating site suitability for future projects, facilitating progress toward China's carbon neutrality target.