Coal fracture's compressibility and permeability under proppant embedding

doi:10.16265/j.cnki.issn1003-3033.2021.10.015

Abstract

Abstract: In order to explore coal fracture's compressibility and permeability under influence of stress and proppant, embedding depth of proppant was quantified by using Hertz contact theory, and a calculation formula of fracture compressibility was derived. Meanwhile, a permeability model was established considering coupling influence of multiple factors, and its validity was verified. The results show that embedding depth of proppant is proportionate to effective stress, and permeability decreases first and then levels off as effective stress grows. When gas pressure is constant, embedding of proppant reduces compressibility of coal fissures, but while at a constant embedding depth, the compressibility increases along with that of gas pressure. Meanwhile, permeability of coal fractures with proppant is much higher than that in the original state, but more paving layers lead to less obvious anti-reflection effect. As the established model's calculated value of permeability is generally consistent with test results, it can can effectively characterize seepage features of coal under actions of stress and proppant.

Key words: proppant embedding, coal, fracture compressibility, permeability, number of paving layers

CLC Number:

X936

CHENG Qiaoyun, LI Bobo, LI Jianhua, GAO Zheng, WANG Bin. Coal fracture's compressibility and permeability under proppant embedding[J]. China Safety Science Journal, 2021, 31(10): 105-111.

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