Effect of grain roughness on permeability and electrical conductivity of porous rock under mineral dissolution

Mineral dissolution widely exists in subsurface reservoirs. Dissolution process can make new flow channels, which leads to the porosity of the underground reservoir alteration, thereby affecting the physical parameters of porous rock such as permeability and electrical conductivity. We apply a linear Boolean model and a four-parameter stochastic generation model to quantitatively investigate the relationship between grain roughness, permeability, and electrical conductivity of porous rocks under dissolution conditions. The dual-distribution function lattice Boltzmann model was used to mimic the dissolution process and permeability evolution in porous rocks. Common dissolution patterns including uniform, surface, and wormhole dissolution, are controlled by two dimensionless numbers, the Peclet number (Pe) and the Damkohler number (Da). By varying Pe and Da, different dissolution regimes were reproduced. We obtain the electric field in porous media using a finite element method based on minimum free energy and then calculated the bulk electrical conductivity based on Ohm's law. Our results indicate that for porous media with the same grain roughness, different dissolution regimes lead to different effects on permeability and electrical conductivity due to changes in pore geometric structure. The wormhole dissolution regime shows the largest variations in permeability and electrical conductivity, while the face dissolution regime exhibits the smallest variations. Under the same Pe and Da conditions, models with higher grain roughness show significantly larger variations in permeability and electrical conductivity.