Simulation of Newtonian and non-Newtonian reactive fluids during the dissolution process in porous media using Lattice Boltzmann method

In this study, the dissolution performance of a non-Newtonian reactive fluid, whose viscosity depends on both shear rate and pH, was compared with that of a Newtonian fluid. An in-situ cross-linked acid, representing non-Newtonian fluids, was employed, and the lattice Boltzmann method was used to simulate its dissolution behavior. The primary objective was to evaluate the dissolution characteristics of both Newtonian and non-Newtonian reactive fluids in fractured systems as well as in more complex porous structures. Furthermore, the effects of two dimensionless numbers, the Peclet number and the Damköhler number, on the dissolution performance of the non-Newtonian reactive fluid in porous media were examined. In porous media, a higher Peclet number for the non-Newtonian fluid resulted in deeper penetration, earlier wormhole formation, and a more pronounced increase in permeability compared with the Newtonian fluid. At a fixed Damköhler number, a higher Peclet number produced a greater enhancement in permeability, while the influence of the Damköhler number on the permeability and porosity of the domain was more intricate. This complexity was attributed to the distinct dissolution patterns generated by the non-Newtonian fluid under different combinations of Damköhler and Peclet numbers in porous media.