The evolution of heterogeneous and anisotropic media in the uniform dissolution regime (low Damköhler number) is studied here using a numerical network model. The uniform dissolution extensively homogenizes the medium and therefore the flow field. The homogenization is further enhanced when the surface reaction is transport controlled—when slow diffusion of dissolved ions away from the mineral surface leads to the reduction of the global dissolution rate. Under those conditions, diffusive transport is more effective in narrow channels, which selectively enlarge, leading to an initial steep rise of the permeability. However, as dissolution proceeds, the void space widens and the overall dissolution rate drops, and permeability enhancement slows down. Finally, we review the relevance of these results to various processes in geological systems ranging from diagenesis and karst evolution, to carbon geosequestration. These findings provide fundamental insights into reactive transport processes in fractured and porous media and evolution of permeability, tortuosity, anisotropy, and bulk reaction rates in geological systems.
FunderR. Holtzman acknowledges partial support from the Israeli Science Foundation (ISF-867/13). P. Szymczak was supported by the National Science Centre (Poland) under research Grant 2016/21/B/ST3/01373.
Israel Water Authority student's scholarship.
- Network model
- Permeability evolution
- Reactive transport
- Uniform dissolution
ASJC Scopus subject areas
- Water Science and Technology