Quantifying the Effect of Pore‐Size Dependent Wettability on Relative Permeabilities Using Lattice Boltzmann Simulation

Abstract Relative permeability is a crucial two‐phase property in porous media that can be significantly impacted by wettability conditions. While traditional research has predominantly examined homogeneous wettability, this work explores the less studied pore‐size dependent (PSD) wettability, featured by a pore‐size dependent wettability distribution. Leveraging high‐fidelity Lattice Boltzmann simulations on CT‐scanned porous samples, we demonstrate how PSD wettability would impact relative permeability at the pore scale. Our findings reveal that the deviation of relative permeability from the homogeneous wettabilitity induced by PSD wettability can be 5%–20%. The deviation of relative permeability curves increases as the spanning range of the contact angle increases. We also find that this impact is less pronounced as the capillary number increases. By adopting a pore‐size‐dependent contact angle relationship, our approach provides a more accurate and nuanced understanding of how PSD wettability would impact two‐phase flow. These findings discovered at the pore scale may also provide valuable insights on relative permeability at the core to reservoir scales.