Study on permeability mechanism of rough fractured coal considering slippage effect
ZENG Xingyi
LI Bobo
LI Jianhua
DUAN Shulei
DING Yunna
YANG Junsong
Abstract：In order to explore the influence of the surface roughness of coal fractures on the permeability characteristics of coal,coal samples from Liupanshui area of Guizhou Province were selected,and the pore structure of coal was characterized by scanning electron microscopy and low-temperature nitrogen adsorption test,and the surface roughness of coal was preliminarily analyzed by Hurst theory.On this basis,the fractal theory is used to further quantitatively characterize the relative roughness of the fracture surface of coal,and a the-oretical model of apparent permeability of coal considering the stress,slippage effect and relative roughness of the fracture surface is es-tablished,and the influence of the relative roughness of the fracture surface on the gas slip factor is discussed,which is verified and ana-lyzed by the laboratory test results of the permeability of coal.The results show that:①SEM test showed that there were rough microele-ments on the surface of the pore fracture structure,and the results of low-temperature nitrogen adsorption test showed that the pore frac-ture structure of coal was developed,with fractal characteristics and strong heterogeneity.②The relative roughness of the surface of coal fractures increases with the increase of the fractal dimension of rough microelements.When the fractal dimension of the rough microele-ment is constant,the relative roughness of the fracture surface decreases with the increase of the scale proportion ε of the rough microele-ment,and the smaller the fracture opening b of the coal,the more sensitive the relative roughness of the fracture surface is to the fracture opening.③With the increase of the relative roughness of the fracture surface,the slippage effect increases.④When the initial slip coeffi-cient is the same,with the increase of pore pressure,the apparent permeability of coal gradually decreases and tends to be flat.The slip-page effect promotes the infiltration of coal,and the larger the slippage coefficient,the stronger the effect.
Keywords：Liupanshui coal mineadsorption modelroughnessslippage effectpermeability model
Publication Date：2025-06-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 120-129 )