Numerical study of capillary-dominated drainage dynamics: Influence of fluid properties and wettability

Abstract

Drainage in porous media, crucial in various engineering, industrial, and pharmaceutical contexts, is influenced by the instability of fluid interfaces, leading to diverse displacement efficiencies. This study employs a color gradient model based on the lattice Boltzmann method for pore-scale simulations, examining effects of fluid viscosity, interfacial tension, and wettability on fluid distribution and pressure variations. Results reveal that higher viscosity ratios intensify the imbibition interface, making the invading fluid more compact early in displacement. Increased interfacial tension amplifies pressure difference fluctuations and enhances imbibition, affecting the displacement front's morphology by enhancing lateral evolution but reducing finger-like structures. A greater contact angle in the defending fluid heightens pressure difference volatility, lowers imbibition interfaces, and improves the displacement front's compactness, thereby boosting overall displacement efficiency. These insights offer foundational theoretical support for optimizing mining and industrial processes considering subtle variations in fluid property and wettability.