Abstract Carbon capture and storage (CCS) technology harnesses the unique properties of supercritical carbon dioxide (scCO 2 ) under reservoir conditions to achieve efficient geological sequestration and is widely recognized as a vital strategy for reducing CO 2 emissions and addressing climate change. However, the flow behavior of CO 2 within reservoirs is strongly influenced by the heterogeneity of the porous media in reservoir rocks, which serves as a critical factor in determining both the efficiency and safety of sequestration. In this study, permeability heterogeneity models were constructed using random functions, and the Volume of Fluid method was employed to simulate scCO 2 displacement of water and investigate the effects of porous media heterogeneity on the two-phase flow behavior. The results reveal that heterogeneity significantly impacts displacement patterns, dominant flow paths, and displacement efficiency during scCO 2 invasion. At low injection capillary number ( Ca ), capillary forces dominate, resulting in capillary fingering, while at high Ca , viscous forces prevail, leading to viscous fingering. In models with weaker heterogeneity, a transition zone from capillary fingering to viscous fingering is observed at intermediate Ca . Conversely, in models with stronger heterogeneity, no transition zone is detected due to the formation of fixed dominant flow paths. Additionally, the final displacement efficiency increases with Ca but decreases with increasing heterogeneity. Greater heterogeneity intensifies fingering effects, leading to higher residual water saturation and reduced invasion efficiency. These findings provide valuable theoretical insights for optimizing CO 2 geological storage operations, highlighting the importance of tailoring injection strategies to reservoir heterogeneity. Properly adjusting injection parameters can suppress fingering effects and improve sequestration efficiency, thereby enhancing the overall effectiveness of CO 2 storage.
Kang et al. (Thu,) studied this question.