Pore-scale investigation on reactive flow in non-uniform dissolved porous media considering immiscible phase by lattice Boltzmann method

The development of shale gas by injecting CO2 is complex, which results in the complicated dissolving process in porous formation. The components of underground formation are complicated and the non-uniform distribution greatly affects heat and mass transfer. In this study, the non-uniform porous media generated by quartet structure generation with dissolved solid, undissolved solid or immiscible phase is studied by lattice Boltzmann method, in which the flow, concentration and temperature fields are solved by Shan-Chen, mass transport and heat transfer lattice Boltzmann model, respectively. The results indicate that the reaction becomes further at the higher Damkohler number, while the diffusion becomes further at the higher Peclet number. The breakthrough time and the dissolution intersection points between the same solid distributions are affected by the solid dissolution rate non-uniformity. The breakthrough area is not affected by the vertical undissolved solid, but is considerably affected by the horizontal undissolved solid. But the breakthrough area is slightly affected by the vertical or horizontal immiscible gas, and the breakthrough time of the cases of immiscible gas is much more than those of undissolved solid.