Characterisation of reactive transport in pore-scale correlated porous media

•Effect of correlation length on reactive transport is quantified.•Unstructured irregular pore spaces with different correlation lengths are generated.•Conceptual diagrams are suggested to characterise reactive transport in porous media.

We apply a reactive transport model to study the effect of correlation length on dissolution and to characterise reactive transport in pore-scale correlated porous media. Porous media with different correlation lengths are derived from correlated fields. An efficient numerical model is employed to simulate dissolution on these geometries for a range of Péclet and Damköhler numbers. The solute concentration distribution is presented in porous media for both low and high correlation lengths. Four types of dissolution patterns are observed in various correlated porous media: face dissolution, uniform dissolution, wormholing and mixed dissolution. The permeability-porosity relationships are also studied in simulations of porous media with different correlation lengths. The permeability in larger correlation length media increases faster at the same Damköhler number. Dissolution patterns of all cases are plotted in a diagram and the effect of correlation length on reaction regimes are analysed. The findings show that larger correlation lengths can result in more uniform and wormholing types of dissolution but less face dissolution. Correlation length plays a critical role in characterising the reaction regimes during reactive transport.