Pore Structure Characteristic And Transport Property Analysis Of Porous Medium

Coalbed is not only a hydrocarbon source rock but also reservoir rock, the coal matrix void space is the reservoir site, and the fissure is the major channels for gas migration. Due to the diverse formation of coal pore texture, therefore which lead to coal microscopic geometry is very complex, which makes the coal porous media representation becomes extremely difficult. Exploring the behavior of coalbed methane migration becomes more difficult. Numerical simulation method as a new research tool, Compared with the experimental testing method, which is not affected by factors such as environment, scale, and so on. In dealing with fluid migration behavior simulation on complex pore structure is better accuracy and higher efficiency than experimental testing method.In this article, both lattice Boltzmann method and fractal geometry theory are employed to simulate complex pore and fracture in coal and fracture-pore porous medium model, what’s more, the effects of micro physical parameters to the permeability was analysised, get the following conclusions and understanding:(1) Based on the scale-invariant of coal structure and theory of series-parallel flow resistance, the fractal pore-permeability relationship was derivated from theoretical level, and the validity of LBM was validated.(2) Combing the geometry characteristic of micro fracture in coal, make the aperture as conference, the influence of geometric profile to the method and strength of flow was analysied. Results show that ①The Parameters between hydraulic turtuosity and the fracture porfile geometry fractal dimension and relative roughness all existed piecewise linear relationship. ②surface tortuosity and absolute roughness meet the linear relationship, but also show the piecewise linear correlation between fractal dimension characteristic.(3) In order to better characterize the real coal rock porous media "low permeability and high connectivity" characteristics, this paper presents a homogeneous voronoi using an iterative method to simulate Coal rock porous media, On this basis, a heterogeneity voronoi method is proposed to reflect the complexity and randomness of true coal porous media,And quantitative analysis of fracture- porosity porous media effects on the permeability of the physical parameters.