Competitive dissolution of binary minerals in porous media: A lattice Boltzmann study

In the geological storage of hydrogen and carbon dioxide in underground salt caverns, the water-injected salt dissolution technology is widely applied in the expansion of salt caverns. During the salt dissolution, a variety of minerals with different properties are often involved, and there are obvious competitive interactions among them. This competition is primarily manifested in differences in diffusion rates, dissolution rates, and ionic concentration equilibrium constraints. In this study, we developed a lattice Boltzmann model, taking into account the competitive dissolution mechanisms of different minerals under the constraint of ion equilibrium. The model was used to investigate permeability changes of porous structure under various injection velocities and different combinations of minerals. The results reveal that whether the physical properties of binary minerals vary greatly or not, such as reaction rate and diffusion rate, the impact of competitive dissolution cannot be ignored. And as the injection rate increases, the influence of the competitive dissolution effect on the pore structure evolution becomes greater. This research provides theoretical insights into binary minerals' competitive dissolution mechanisms and references for its applications in fields such as environmental science, resource development, and chemical engineering.