A Model for Gas Transport in Dual-Porosity Shale Rocks with Fractal Structures

A model for shale gas flow in a fractal dual-porosity rock is built and well validated with experimental data. Results indicate that (1) the gas transport in shale natural fractures gradually becomes a higher priority in the dual-porosity rock with the increase of fracture porosity; (2) the ratio of minimum fracture aperture to a fracture aperture and the fractal dimension of fracture together contribute to the fracture aperture distribution. More fractures with larger aperture exist in shale rock with larger minimum fracture aperture, which benefits gas apparent permeability; (3) a natural fracture-dominant region enlarges with decreasing fractal dimension of fracture aperture and increasing minimum fracture aperture, and this is beneficial to the improvement of the gas apparent permeability.