Complex hydraulic fracture networks are critical for enhancing permeability in unconventional reservoirs and mining industries. However, accurately simulating the fluid flow in realistic fracture networks (compared to the statistical fracture networks) is still challenging due to the fracture complexity and computational burden. This work proposes a simple yet efficient numerical framework for the flow simulation in fractured porous media obtained by 3D high-resolution images, aiming at both computational accuracy and efficiency. The fractured rock with complex fracture geometries is numerically constructed with a cell-based discrete fracture-matrix model (DFM) having implicit fracture apertures. The flow in the complex fractured porous media (including matrix flow, fracture flow, as well as exchange flow) is simulated with a pipe-based cell-centered finite volume method. The performance of this model is validated against analytical/numerical solutions. Then a lab-scale true triaxial hydraulically fractured shale sample is reconstructed, and the fluid flow in this realistic fracture network is simulated. Results suggest that the proposed method achieves a good balance between computational efficiency and accuracy. The complex fracture networks control the fluid flow process, and the opened natural fractures behave as primary fluid pathways. Heterogeneous and anisotropic features of fluid flow are well captured with the present model.

复杂的水力裂缝网络对于提高非常规油藏和采矿业的渗透率至关重要。然而，由于裂缝的复杂性和计算负担，准确模拟现实裂缝网络中的流体流动（与统计裂缝网络相比）仍然具有挑战性。这项工作提出了一种简单而有效的数值框架，用于通过 3D 高分辨率图像获得的裂缝多孔介质中的流动模拟，旨在提高计算精度和效率。使用具有隐式裂缝孔径的基于单元的离散裂缝矩阵模型（DFM）对具有复杂裂缝几何形状的裂缝岩石进行数值构建。采用基于管道的单元中心有限体积法模拟了复杂裂缝性多孔介质中的流动（包括基质流、裂缝流以及交换流）。该模型的性能根据分析/数值解决方案进行了验证。然后重建实验室规模的真实三轴水力压裂页岩样本，并模拟该真实裂缝网络中的流体流动。结果表明，所提出的方法在计算效率和精度之间取得了良好的平衡。复杂的裂缝网络控制着流体流动过程，打开的天然裂缝充当主要的流体通道。本模型很好地捕捉了流体流动的非均质和各向异性特征。