Numerical Simulation On Flow Coupling In A Triple-Fracture Network Model Based On Fractal Geometry Theory

This study presents numerical simulations on fluid flow under high stress and intense hydraulic activity and focuses on complex reservoirs with porous and fractured microstructures based on fractal geometry theory. A Triple-Fracture Network model, which includes pores, micro-fractures and macro-fractures, is categorized into fractal fracture networks and fractal pore systems based on fractal geometry theory. Using the Monte Carlo method, we construct macroscopic randomly distributed fractures to examine the impact of macro-fracture topological structures on flow dynamics. Fractal permeability models for micro-fracture and micro-pore systems are developed, incorporating variables such as fracture lengths and pore sizes. The proposed approach partitions porous media into macroscopically discrete fractures and microscopically characterized pores, utilizing fractal geometry theory to analyze hydro-mechanics coupling. The validity of the proposed model is confirmed through comparisons with analytical solutions and available models as well as the published field data. This results indicate that the spatial distribution of the effective stress and macroscopic fractures significantly affects the fractal dimensions of microscopic fractures and pores. It is found that the density of macro-fractures influences the fracture pressure, while the initial porosity and proportionality constant β of micro-fractures impact the pressure distributions in the tested domains. It is found that the maximum length of micro-fractures correlates positively with permeability. This model introduces a novel perspective on random macro-fractures and fluid coupling in microstructures, enhancing the understanding of macro- and micro-hydrodynamics interactions.