Assessment of wetting conditions in quasistatic drainage modeling using a pore morphology method and J-function wettability estimator

Abstract

This study hypothesizes that a pore morphology method (PMM) can be used to accurately determine representative contact angles by effectively capturing fluid morphologies within porous media, thereby overcoming the challenges of accurate wettability characterization for porous materials. We introduce a methodology for the estimation of the wettability, along with measurements of capillary pressure and relative permeability, using a PMM. This approach employs morphological operations to model quasistatic drainage under different surface wetting conditions. To assess PMM, fluid morphologies resulting from the simulation were compared with experimentally derived geometric and thermodynamic contact angles, along with surface area, and Euler characteristic measurements. Based on fluid configurations under different wettability conditions, we find that PMM effectively captures realistic fluid morphologies. At lower capillary pressures, PMM exhibits superior adaptability to a wide range of wetting behaviors. However, at higher capillary pressures, PMM does not reflect the true morphologies of the fluid due to the interfaces that exist in the pendular state. The influence of these effects at higher capillary pressures introduces an inaccuracy in the simulated relative permeability of the wetting phase, though they do not affect the relative permeability of the nonwetting phase. Overall, these findings can significantly enhance the accuracy of wettability characterization in porous media, thereby advancing our understanding and prediction of fluid behavior in surface-based research of porous materials.