Study on model for coal rock permeability anisotropy and simulation of gas extraction

doi:10.16265/j.cnki.issn1003-3033.2018.12.018

Abstract

Abstract: In order to further clarify coal rock permeability evolution law and influence of matrix gas seepage on gas extraction, based on the existing fluid-solid coupling model of matrix gas seepage, considering anisotropic characteristics of coal permeability, a permeability anisotropy coupling model of coal rock was built. COMSOL Multiphysics software was used to analyze the anisotropic permeability characteristics of coal rock and the influence of matrix gas seepage on gas extraction. The results show that with the increase of permeability anisotropy coefficient, the ratio coefficient of matrix to fracture permeability decreases, and the effect of gas extraction is obviously reduced, that the peak value of matrix gas seepage rate increases with the increase of anisotropy coefficient, but matrix gas seepage rate in the middle and late stages of gas extraction is gradually stable, and the value is about 0.1%, and that the matrix gas seepage term plays a promoting part at a certain stage in gas extraction.

Key words: gas extraction, permeability anisotropy, fluid-solid coupling, matrix gas seepage, permeability evolution characteristics

CLC Number:

X936

ZHANG Haohao, LI Sheng, FAN Chaojun, WANG Xiaohe, GUO Yunfeng, TAO Mei. Study on model for coal rock permeability anisotropy and simulation of gas extraction[J]. China Safety Science Journal, 2018, 28(12): 109-115.

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