Pore-scale study of dissolution-induced changes in permeability and porosity of porous media

We apply a reactive transport lattice Boltzmann model developed in previous studies to study the dissolution-induced changes in permeability and porosity of two porous media at the pore scale. The permeability-porosity relationship is explored for a wide range of Peclet and Damkohler numbers. It is found that this relationship depends not only on different dissolution regimes characterized by Pe and Da, but also on the specific porous medium structure. The permeability-porosity relationship for the more geometrically complex porous medium shows much more complexity than that for the simple fractured medium. While a very small Da sets an upper bound for the permeability-porosity relationship for the simple medium, a combination of a high Da and Pe results in wormholing, and the fastest permeability increase for the complex medium. At a moderate Pe but large Da, a transition from transport-limited dissolution regime to wormholing is also observed for the complex medium. (C) 2014 Elsevier B.V. All rights reserved.