Numerical modeling of fluid flow in fractured porous media using Lattice Boltzmann method

Complex fluid flow and transport in fractured porous media is topical in both microfluids research and its industrial applications. Usually, traditional REV-scale method is used to analyze and depict fluid phenomenon in porous matrix. However it shows disadvantages of revealing fluid characters at particle-level void/solid space. Based on Lattice Boltzmann method, our research focuses on interface effects of pore fluids and porous solids, and fractures influence on fluid behaviors. To realize detailed particle-level simulation, we 1) design porous media matrix according to average macroscopic porosity using Weibull distribution: each node of lattice describing pores or solids has its own local porosity as matrix property; 2) define each solid-particle node to be partly through by fluid particles, instead of simply treating the solid-fluid interface as no-slip/slip boundary; 3) propose a modified force model for the purpose of modeling simplification and computational performance optimization. Simulation results demonstrated that considering the through ability of solid-particle nodes, complicated interface effects and fluxes influence on fluid are observed; pore channels and fracture networks inside porous matrix have obvious influence on macroscale qualities, such as velocity distribution.