Permeability prediction for coal reservoirs and reconstruction of a different scales pore-fractures network

Fine describing the connectivity of different scaled pore-fractures and quantitatively expressing permeability can provide an important basis for the output degree of the gas. Different scales pore-fractures network was reconstructed by observing large number of coal samples and software simulation of Monte Carlo method. Seepage model about different scales pore-fractures network was established by assigning zero method and using MatLab software. Effect permeability about different scales pore-fractures network was obtained by two-dimensional seepage equation. Predicting permeability results is compared with the measured permeability results, the results showed that: the dominant order of different scales pore-fractures connected path from high to low is millimeters fractures, seepage pores and micron-sized fractures. The contribution of coal reservoir permeability from big to small is millimeters fractures, micron-sized fractures and seepage pores. Different parameters in different scales pore-fractures are of different influences to permeability. Reconstruction of different scales pore-fractures network can clearly display the connectivity of pore-fractures, which can provide a basis for selecting migration path and studying flowing pattern about gas.