Method for integrally sealing and separating gas extraction drilled hole in coal seam

Abstract

The invention discloses a method for integrally sealing and separating a gas extraction drilled hole in a coal seam, and in particular is applied to sealing of a gas extraction drilled hole in the coal seam and gas extraction drilled holes in the adjacent coal seams. The method comprises the following steps of: forming a sealing space in the drilled hole by filling sealing materials; extracting high-concentration gas in an initial drilled hole by using an extraction pipeline; sealing the extraction drilled hole by using materials such as accelerated cement; and when the concentration of gas to be extracted is reduced to a relatively low level, spraying the surface of a laneway surrounding a drilling site by using sealing and separating materials, and forming a low-permeability separating layer serving as a connection channel for separating inner cracks and external air on the surface of the laneway so as to seal the extraction drilled hole. By the method, air leakage channel can be effectively sealed in the gas extraction process, and a phenomenon that air enters is avoided, so that the concentration of the gas in the extraction drilled hole is greatly increased, and the service life of the gas extraction drilled hole in the coal layer is prolonged.

Description

technical field [0001] The invention relates to a hole sealing method, in particular to a coal seam gas drainage borehole sealing integrated hole sealing method suitable for sealing a coal seam gas drainage borehole and an adjacent layer gas drainage borehole in a coal mine. Background technique [0002] Coal seam gas drainage is one of the most effective and direct methods to solve the problem of coal mine gas, and the sealing effect directly affects the gas drainage effect. At present, the most commonly used hole sealing methods are mechanical hole sealing device sealing and filling sealing material sealing (including cement mortar, yellow mud and polyurethane sealing). A sealed space is formed inside the borehole. However, with the progress of gas extraction, the coal seam deforms, and the coal seam pores and fissures around the borehole gradually develop, forming gas leakage channels connected with the roadway wall, resulting in a significant reduction in the gas extrac...

AI Technical Summary

Problems solved by technology

However, with the progress of gas extraction, the coal seam deforms, and the pores and fissures in the coal seam around the borehole gradually develop, forming gas leakage channels connected with the roadway wall, which greatly reduces the concentration of gas drainage

About 65% of the coal mining faces in my country have pre-drainage gas concentrations lower than 30%, which fully reflects the poor quality of gas drainage borehole sealing, and it is also enough to show that sealing in the borehole alone cannot guarantee the drainage effect

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