A Fractal Orifice-Throat Model for Seepage Characteristics of Multiscale Porous Media

The seepage characteristics of multiscale porous media is of considerable significance in many scientific and engineering fields. The Darcy permeability is one of the key macroscopic physical properties to characterize the seepage capacity of porous media. Therefore, based on the statistically fractal scaling law of porous media, fractal geometry is applied to model the multiscale pore structures. And a two-dimensional fractal orifice-throat model with multiscale and tortuous characteristics is proposed for the seepage flow through porous media. The analytical expression for Darcy permeability of porous media is derived, which is validated by comparing with available experimental data. The results show that the Darcy permeability is significantly influenced by porosity, orifice-throat fractal dimension, minimum to maximum diameter ratio, orifice-throat ratio and tortuosity fractal dimension. The present results are helpful for understanding the seepage mechanism of multiscale porous media, and may provide theoretical basis for unconventional oil and gas exploration and development, porous phase transition energy storage composites, CO₂ geological sequestration, environmental protection and nuclear waste treatment, etc.