Pore-Scale Modified Image-Based Invasion Percolation Simulation on CO₂ Transport and Trapping Behavior in Low Permeability Porous Sandstone

To assess Carbon dioxide Capture and Storage capacity and security, the necessity of analyzing residual trapping of CO₂ is evident. However, the previous studies have primarily focused on mesoscale CO₂ residual trapping, neglecting the significant contributions from the pore scale, which crucially influences CO₂ behavior due to rock heterogeneity. Here, we propose a modified Image-Based Invasion Percolation (MIBIP) simulation model to simulate CO₂ residual trapping behavior on a pore-scale and discuss the possibilities of CO₂ storage in low-permeability sandstone. First, the MIBIP simulation model is used to replicate the pore-scale CO₂ injection experiment, and the simulation result is almost the same as the experiment, which verified the accuracy of the MIBIP simulation model in simulating the CO₂–Water displacement process. Then, applying the MIBIP simulation on higher resolution pore distribution models, the details of CO₂ transient saturated distribution and how pores are invaded by CO₂ can be clearly visualized. The result reveals that many trapping domains have CO₂ invaded before the breakthrough. Additionally, CO₂ is more likely to be trapped in the dead-end pores connected to connected pores through narrow throats. Finally, we demonstrate that a good low-permeability domain can achieve a much higher residual trapping ability at a higher degree of heterogeneity than an uncorrelated random domain. This work provides an effective tool for further understanding CO₂ transport and trapping behavior at the pore-scale and optimized enhanced CO₂ sequestration.