Lattice-Boltzmann simulation of microscale CH4 flow in porous rock subject to force-induced deformation

Accurate knowledge of the influence of rock deformation on the permeability of fluid flow is of great significance to a variety of engineering applications, such as simultaneous extraction of coal and gas, oil/gas exploitation, CO2 geological sequestration, and underground water conservation. Based on the CT representation of pore structures of sandstones, a LBM (Lattice Boltzmann Method) for simulating CH4 flow in pore spaces at microscale levels and a parallel LBM algorithm for large-size porous models are developed in this paper. The properties of CH4 flow in porous sandstones and the effects of pore structure are investigated using LBM. The simulation is validated by comparing the results with the measured data. In addition, we incorporate LBM and FEM to probe the deformation of microstructures due to applied triaxial forces and its influence on the properties of CH4 flow. It is shown that the proposed method is capable of visually and quantitatively describing the characteristics of microstructure, spatial distribution of flow velocity of CH4, permeability, and the influences of deformation of pore spaces on these quantities as well. It is shown that there is a good consistency between LBM simulation and experimental measurement in terms of the permeability of sandstone with various porosities.