Pore-scale investigation on mineral dissolution and evolution in hydrological properties of complex porous media with binary minerals

Abstract

A pore-scale numerical model for reactive transport process based on lattice Boltzmann method is adopted to simulate the mineral dissolution in complex porous media with binary minerals. The effect of binary mineral, solute concentration and dissolution rate on hydrological properties evolution of complex porous media is investigated. Simulation results show that binary minerals could inhibit the mineral dissolution and further alter the temporal evolution trend of related hydrological properties compared to monomineralic porous media. Changes in pore structure of complex porous media could be divided into three stages: slow increase, significant increase and slightly-stable increase stage in succession. A simple model is barely suitable for characterizing the porosity-permeability evolution of the complex porous media. Temporal evolution in reactive specific surface during mineral dissolution could be characterized by the fractal model. Although solute concentration could change the mineral dissolution process, it has no effect on the evolution relationship of hydrological properties between permeability, reactive specific surface and porosity. Mineral dissolution rate would alter the above-mentioned relationships by changing the reactive transport regime.