Research on permeability enhancement of coal seam  by compound perforation technology

doi:10.16265/j.cnki.issn1003-3033.2019.06.018

Abstract

Abstract: In order to increase the permeability of low permeability and high gas seam and improve gas utilization and extraction efficiency, a composite perforation blasting technology was proposed. Based on the theories of elastic mechanics and fracture mechanics, the crack strength factor and the crack secondary propagation radius equation of composite perforated detonation gas fracturing crack were established respectively, and the mechanism of coal rock fracture expansion was studied. FLAC^3D finite difference simulation software was used to analyze the effect of different lengths of cracks in blasting borehole on the effect of blasting and penetration. Industrial tests were carried out to compare the effects of underground composite perforation blasting and conventional pre-splitting blasting, and the gas extraction radius of coal seam after pre-splitting was determined by the variation characteristics of gas permeability. The results show that the gas permeability of coal seam after compound perforation blasting is significantly higher than that of conventional deep hole pre-splitting blasting and the effective radius can reach 5 m, and that the numerical simulation and field test prove that the gas permeability of coal seam can be effectively increased and the extraction rate can be improved by using compound perforation blasting.

Key words: air permeability, composite perforation, coal-rock fracture, SF₆ tracer gas, permeability improvement effect, effective radius

CLC Number:

X936

ZHAO Dan, LI Bin, LEI Yun, PAN Jingtao. Research on permeability enhancement of coal seam by compound perforation technology[J]. China Safety Science Journal, 2019, 29(6): 109-115.

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Research on permeability enhancement of coal seam by compound perforation technology

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