Lattice Boltzmann simulation of dissolution patterns in porous media: Single porosity versus dual porosity media

Abstract

Understanding the influence of porous media structure, particularly dual porosity, on solvent transport and pore geometry evolution during chemical reactions is a complex and critical area of study. This research leverages the lattice Boltzmann method to investigate how the presence of aggregates in a medium affects solvent transport and pore space development, focusing on distinct dissolution regimes: face and wormhole dissolution. The study addresses the challenge of managing variable pore sizes in dual porosity media by developing specialized GPU algorithms, which efficiently handle fine grids and complex pore spaces. The findings reveal that dual porosity significantly enhances dissolution rates in both the face and wormhole dissolution regimes. Intriguingly, while the pattern of face dissolution remains largely unchanged, dual porosity markedly alters the pattern of wormhole dissolution. In dual-porosity media, the wormholes tend to be narrower and more elongated compared to the wider wormholes observed in single-porosity media. This variation is attributed to the reaction area dynamics, where the reduced reactive surface area along the main wormhole path in dual-porosity media results in less solvent engagement in the reaction processes. Moreover, the research provides insights into the microscale interactions in porous media, emphasizing how variations in microscale porosity can have substantial impacts on the overall dissolution dynamics. The study results are not only significant for understanding the fundamental aspects of chemical dissolution in porous media but also have practical implications in fields such as geo-energy and groundwater remediation. These findings help optimizing reaction processes in complex and heterogeneous porous systems, highlighting the need for detailed consideration of microstructural characteristics in modeling and industrial applications.