A Novel Permeability–Tortuosity–Porosity Model for Evolving Pore Space and Mineral-Induced Clogging in Porous Medium
Wenran Cao, Guanxi Yan, Harald Hofmann, Alexander Scheuermann
Abstract
Hydrogeochemical processes contribute to long-term alterations in key physical properties of a porous medium, including porosity, tortuosity, and permeability, making it essential to understand their evolution and address clogging-dominated problems in hydrogeological systems such as acid rock drainage treatment and aquifer storage and recovery. However, accurately simulating extreme cases of evolving pore space presents challenges due to the inherent heterogeneity and nonlinear reactions in a porous medium. In response, this study introduces a comprehensive model that integrates the effects of tortuosity on permeability and surface area on reactivity during oxidative precipitation of Fe(II) in a porous medium. Benchmark simulations include an innovative permeability–tortuosity–porosity model accounting for Fe precipitation, as well as the occurrence of complete clogging from localized precipitation, which leads to a reduction of permeability and outflow. The outcomes demonstrate complete pore clogging when Fe(II) concentration reaches 10 mmol/L and a significant decrease in outflow at a Fe(II) concentration of 100 mmol/L. The model’s predictions provide detailed insights into the evolution of the pore matrix during hydrogeochemical reactions and support the development of regional engineering-scale models for applications in mining, agriculture, and environmental management.