LBM-based Simulation on Impact of Wettability Heterogeneity on Relative Permeability in Sandstone

It is widely accepted that pore-scale wettability heterogeneity can alter the distribution of multiphase fluids within pore space, dynamic process of displacement, and associated macroscopic characteristic, such as relative permeability. To get fundamental understanding the impact of wettability heterogeneity on relative permeability, we developed a numerical simulation which is based on the lattice Boltzmann method to directly simulate process of displacement in oil/brine/rock system. The dimension of computational domain will be 800×800×600 pixels which is based on CT images with resolution of 2.36 μm/lu. The wettability is represented by contact angle. The statistical characteristics of contact angles is directly measured from images on distribution of oil and brine in sandstone scanned by CT in the laboratory experiment. The distribution of contact angles in computational domain is generated according to multivariant normal distribution following the measured statistical characteristics. The initialization of the simulation is completed by a morphological opening operation to obtain desired fluid saturations. The distribution of oil and water in sandstone in different scenarios with different contact angle heterogeneity characteristics will be observed. The impact of wettability heterogeneity on relative permeability, and the interaction with capillary number, viscosity ratio associated with the fluid dynamics in the sandstone will be investigated and discussed.