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

Area of Science:

• Earth Science
• Computational Science
• Petroleum Engineering

Background:

• Complex hydraulic fracture networks are vital for enhancing permeability in unconventional reservoirs and mining.
• Simulating fluid flow in realistic fracture networks presents computational challenges due to complexity.

Purpose of the Study:

• To develop a simple and efficient numerical framework for fluid flow simulation in fractured porous media.
• To achieve both computational accuracy and efficiency in modeling complex fracture networks.

Main Methods:

• A cell-based discrete fracture-matrix model (DFM) with implicit fracture apertures was used to construct fractured rock geometries from 3D images.
• A pipe-based cell-centered finite volume method was employed to simulate flow, including matrix, fracture, and exchange flow.
• Model performance was validated against analytical and numerical solutions, and applied to a lab-scale hydraulically fractured shale sample.

Main Results:

• The proposed method demonstrates a favorable balance between computational efficiency and accuracy.
• Complex fracture networks were shown to significantly control fluid flow processes.
• Opened natural fractures were identified as primary fluid pathways, and heterogeneous, anisotropic flow features were captured.

Conclusions:

• The developed numerical framework provides an efficient and accurate approach for simulating fluid flow in complex fractured porous media.
• Understanding fluid flow in realistic fracture networks is essential for optimizing resource recovery in unconventional reservoirs and mining.
• The model's ability to capture flow heterogeneity and anisotropy highlights its utility in analyzing subsurface fluid dynamics.