Quantitative characterization of irregular micro-fracture network and its effect on the permeability of porous media

Based on the comprehensive understanding on microfractures and matrix pores in reservoir rocks, numerical algorithms are used to construct fractured porous media and fracture-pore media models. Connectivity coefficient and strike factor are introduced into the models to quantitatively characterize the connectivity and strike of fracture network, respectively. The influences of fracture aperture, fracture strike and fracture connectivity on the permeability of porous media are studied by using multi-relaxation-time lattice Boltzmann model to simulate fluid flow in them. The greater the strike factor and the smaller the tortuosity of the fractured porous media, the greater the permeability of the fractured porous media. The greater the connectivity coefficient of the fracture network is, the greater the permeability of the fracture-pore media is, and the more likely dominant channel effect occurs. The fracture network connectivity has stronger influence on seepage ability of fracture-pore media than fracture aperture and fracture strike. The tortuosity and strike factor of fracture network in fractured porous media are in polynomial relation, while the permeability and fracture network connectivity coefficient of the fracture-pore media meet an exponential relation.

Automated summary

The study examined the effects of fracture aperture, strike, and connectivity on the permeability of fractured porous media, revealing that a greater strike factor and smaller tortuosity lead to higher permeability. Moreover, higher connectivity coefficient in the fracture network results in higher permeability for fracture-pore media, with a tendency toward dominant channel effects. Ultimately, connectivity in the fracture network has a greater impact on the seepage ability of fracture-pore media compared to fracture aperture and strike.