Using computational fluid dynamics to compute the pore-scale CO2-brine relative permeability

•A workflow to compute CO2-Brine Kr based on CFD has been developed.•The effects of pore-geometry on Kr curves have been investigated.•Dependency of Kr curves on the size of computational domain has been discussed. Global warming is considered as a severe growing crisis over the next years. Carbon Capture and Storage (CCS) has been proposed as a feasible solution to stop the uprising trend of temperature. The satisfactory performance of the CCS implementation is obtained only if the relevant mechanisms are understood well. Undoubtedly, multiphase flow is the most significant common aspect of all effective mechanisms. Relative permeability is recognized as the parameter to describe multiphase flow physics qualitatively and quantitatively. Moreover, previous studies have shown that pore-scale phenomena strongly influence relative permeability data. However, the classic experimental procedures of relative permeability measurements are inherently unable to describe how microscopic phenomena like pore geometries, fluid–fluid interactions, and flow regimes affect the relative permeability data. Based on micro X-ray Computed Tomography (µxCT) images and Computational Fluid Dynamics (CFD), the current research has put forward a systematic workflow to figure out how pore geometry impacts the relative permeability data. Furthermore, the effect of computational domain size on calculated relative permeability data has thoroughly been investigated as well. The results show that realistic relative permeability data are acquired if the effects of pore-scale phenomena are considered.