Presented on 21 May 2026: Session 26 Safe and efficient geological storage of carbon dioxide (CO2) depends on how CO2 and brine move through reservoir rocks and how much CO2 becomes permanently trapped. In this study, a digital core analysis (DCA) approach is used to investigate CO2-brine flow behaviour and residual trapping in sandstone samples from the Paaratte Formation in the Otway Basin, Australia. High-resolution micro-computed tomography (micro-CT) images were acquired for sandstone core samples and processed to generate three-dimensional digital rock models. Image segmentation was carefully calibrated using laboratory porosity measurements, and pore-network models were further adjusted to match experimentally measured permeability. Two-phase pore-network simulations were then carried out under reservoir conditions to represent CO2 injection (drainage) followed by brine injection (imbibition). The simulations provide relative permeability, capillary pressure, and residual CO2 saturation. Results show residual trapping of CO2 is strongly affected by pore geometry and wettability. Rocks with lower pore-throat aspect ratios show better CO2 connectivity and less trapping, while higher aspect ratios promote snap-off and increase trapped CO2. Initial–residual saturation relationships were analysed using Land’s trapping model, showing that both initial CO2 saturation and advancing contact angle control trapping efficiency. Moreover, the results demonstrate that calibrated DCA combined with pore-network modelling provides a reliable and efficient framework for estimating key multiphase flow properties and improving predictions of CO2 storage performance. To access the Oral Presentation click ‘Supplementary data’ below. To read the full paper click here
Masoud Aslannezhad (Thu,) studied this question.