Digital Core Analysis and Pore Network Modeling of CO2 Flow and Trapping in the Otway Basin

This research utilizes three-dimensional pore-scale imaging of cores from the Paaratte Sandstone in the Otway Basin, obtained through micro-CT, to investigate CO2 storage potential and multiphase flow characteristics. Capillary trapping, a critical mechanism for CO2 storage, was thoroughly examined in the context of CO2-brine displacement in a water-wet system. Using pore-scale modeling, drainage and imbibition curves were generated to determine key parameters, including initial and residual saturations, drainage and imbibition capillary pressures, and relative permeability for CRC-8 rock types. A comprehensive assessment of uncertainties and sensitivities is also included in the analysis. Model-generated curves enabled an exploration of the impact of variables such as wettability and initial water saturation, providing valuable insight into the sensitivity of CO2 trapping mechanisms. Notably, our model allowed for an exploration of sensitivity to contact angle, showing that increased contact angles correspond to a reduction in residual trapping. This study’s results underscore the potential of digital rock technology for enhancing understanding of geological CO2 storage. Through high-resolution imaging, experimental measurements, and pore network modeling, insights into the key mechanisms influencing CO2 trapping and multiphase flow in reservoir rocks were gained, providing a foundation for improved reservoir characterization and modeling.