Anomalous Solute Transport in Cemented Porous Media: Pore‐scale Simulations

Abstract

Core Ideas The porous media with higher cementation degree have wider velocity spreads. The solute transport becomes more anomalous with increasing cementation degree. It is the changing characteristics of the flow field that lead to more anomalous solute transport. The pore structure of porous media varies significantly with the change in the degree of cementation among solid grains, and recent studies have shown that pore structure greatly influences anomalous solute transport. Nevertheless, limited effort has been devoted to explore the change in the degree of anomalous solute transport with increasing cementation. In this study, we performed pore‐scale numerical simulations to investigate the anomalous dispersion in computer generated two‐dimensional porous media with different degrees of cementation. The simulated pore‐scale fluid fields show that porous media have wider spreads of velocities when the cementation degree increases. When the percentage of cemented solid grains increases from 0.0 to 57.8%, the stagnant regions' area extends more than 11 times, and preferential flow region increases by a factor of more than 6. These changing characteristics of the flow field as the cementation degree increases make solute transport more anomalous. Therefore, we should be careful when applying an advection–dispersion equation (ADE) to predict solute transport in highly cemented porous media.