An efficient 3D cell-based discrete fracture-matrix flow model for digitally captured fracture networks

• Published in: International journal of coal science & technology 2023-12, Vol.10 (1), p.70-70, Article 70
• Main Authors: Sun, Lei, Li, Mei, Abdelaziz, Aly, Tang, Xuhai, Liu, Quansheng, Grasselli, Giovanni
• Format: Article
• Language: English
• Subjects: Accuracy; Anisotropy; Cell-based DFM; Digital image; Efficiency; Energy; Finite volume method; Flow characteristics; Flow simulation; Fluid flow; Fossil Fuels (incl. Carbon Capture); Fractured porous medium; Fractures (Geology); Geotechnical Engineering & Applied Earth Sciences; International economic relations; Mineral industry; Mineral Resources; Mining industry; Permeability; Porous media; Simulation; Subsurface Flow Modeling for Energy Harvest and Carbon Storage
• ISSN: 2095-8293; 2198-7823
• DOI: 10.1007/s40789-023-00625-1

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. Highlights Simple yet efficient method for fluid flow simulation in digital fracture network Fracture representation using a cell-based DFM with implicit fracture aperture A pipe-based cell-centered finite volume method for fluid seepage simulation Achieve a good balance between computational efficiency and accuracy Capture heterogeneous and anisotropic fluid flow characteristics