A level set based computer simulation of coupled flow and mineral precipitation/dissolution in fracture apertures and porous media

Coupled fluid flow and reactive transport processes involving mineral precipitation and dissolution in fracture apertures and porous media are important to a large variety of scientific and engineering applications, such as acid stimulation of oil reservoirs, in-situ immobilization of contaminants in groundwater etc. We developed a level set based simulation technique to model the coupled reactive flow and structural evolution within pores and fracture apertures. Convection, diffusion and chemical reactions resulting in changes in the pore geometries and fracture apertures are modeled simultaneously by solving coupled momentum, reaction and solute transport equations. The reaction-induced evolution of solid grain surfaces and fracture walls is captured by using a level set interface tracking method. We obtain a more elegant sub-grid representation of the curved interface using a level set approach, compared to the pixel-like representation of the interface used in most simple Lattice Boltzmann simulations. The model was validated against analytical solutions for simplified geometries. Different precipitation/dissolution patterns in porous media and fractures were obtained in our simulations for different combinations of reaction rates and diffusion rates. Quantitative relationships between the hydraulic properties (e.g. permeability and porosity) of the media and their temporal evolutions can also be obtained from simulations.