Modeling Immiscible Fluid Flow: Insights into Air Displacement of Water in Microscale Porous Media

Abstract

This study presents a comprehensive analysis of immiscible displacement phenomena, focusing on the displacement of water by air in an artificial porous medium. The research combines experimental approaches using transparent micromodels and numerical simulations conducted with COMSOL Multiphysics, offering an in-depth understanding of the physical processes governing immiscible fluid displacement in porous structures. At the core of the study is the experimental observation of air injection into a water-saturated artificial porous medium. These experiments were meticulously designed to mirror realistic subsurface conditions and provided a clear visual insight into the immiscible displacement process. The transparent micromodels employed in these experiments were instrumental in visualizing the interaction between air and water phases, capturing the intricate development of preferential pathways as air displaces water within the medium. Complementing the experimental observations, numerical analyses using COMSOL Multiphysics provided a theoretical framework to validate and expand upon the experimental results. These simulations were crucial in quantifying the dynamics of immiscible displacement under varied conditions, offering a detailed perspective on the interplay between air and water phases within the porous medium. The synergy between experimental and numerical approaches allowed for a holistic understanding of the displacement mechanics, ensuring both visual and quantitative insights. A significant aspect of this research was investigating the impact of injection pressure and wettability on the displacement process. Both parameters are known to critically influence the behavior of immiscible fluids in porous media. The study meticulously compared the effects of varying these parameters in both experimental and numerical settings. This comparison offered valuable insights into how changes in injection pressure and surface wettability affect the formation and evolution of preferential pathways, as well as the overall efficiency of the displacement process. One of the key findings of this study is the remarkable similarity in displacement patterns observed in both experimental micromodels and numerical simulations. This consistency not only validates the numerical model used but also underscores the reliability of the experimental approach in replicating real-world conditions. The observed displacement patterns shed light on the complex dynamics governing immiscible fluid flow in porous media, highlighting the interplay of factors such as capillary forces, fluid viscosity, and medium heterogeneity.