The geometric complexity of the 3D pore-fracture system of tight rock at the pore-scale is a primary challenge for the prediction of gas flow. In this paper, the 3D pore-fracture systems of tight rock are reconstructed based on the representation unit volume (REV) of the intact tight sandstone and fractal fracture. A 3D regularized lattice Boltzmann model that considered the gas slippage effect is employed to simulate gas flow in the 3D pore-fracture systems. Effects of the micro-fracture morphology and gas rarefaction effect on gas flow and permeability of the pore-fracture systems are examined and investigated. The simulation results indicate that the gas flow behaviors in the pore-fracture system are strongly related to the above two factors. Gas flow behaviors in the pore-fracture structure is more sensitive at the low-pressure condition and gas rarefaction effect are more sensitive to the pore-fracture system with the highly rough fracture or the low fracture connectivity.

在孔隙尺度上，致密岩石的3D孔隙破裂系统的几何复杂性是预测气流的主要挑战。本文基于完整的致密砂岩和分形裂缝的表示单位体积（REV），重建了致密岩石的3D孔隙裂缝系统。考虑气体滑移效应的3D正则化格子Boltzmann模型用于模拟3D孔隙裂缝系统中的气流。研究并研究了微裂缝形态和气体稀疏效应对孔隙裂缝系统的气体流动和渗透率的影响。模拟结果表明，孔隙裂缝系统中的气体流动行为与上述两个因素密切相关。