Channeling, Clogging and Permeability Oscillations: Different Macroscopic Regimes in Mineral Replacement

Abstract

We consider a porous medium infiltrated by a reactive fluid which triggers coupled dissolution-precipitation reactions at pore surfaces. To study these processes, we model the medium as a system of interconnected pipes with the diameter of each segment changing in proportion to the local reactant consumption. With this model, we investigate different growth regimes in an evolving porous medium, allowing for both erosion and precipitation of the dissolved material. The interplay of flow, transport and reaction in such a system can give rise to a variety of patterns: from spontaneous channeling to nearly homogeneous transformation of the entire rock matrix into the product phase. Interestingly, even if the product phase has a larger molar volume than the parent phase, clogging in such a system can be avoided, due to the interplay of dissolution and precipitation resulting in the continuous creation of new flow paths. These results can be relevant for the analysis of carbonation reactions, in which an important goal is to avoid clogging of the pore space that can lead to permeability reduction and the overall slowdown of the process.