Low-gas-permeability coal seam pressure-releasing and gas-extraction method

Abstract

The invention discloses a low-gas-permeability coal seam pressure-releasing and gas-extraction method in the technical field of coal mining. The low-gas-permeability coal seam pressure-releasing and gas-extraction method comprises the following specific steps that S1, a plurality of drill sites are arranged on a stable top plate of a coal field; S2, six double-position drill holes are formed in each drill site; S3, in the drilling process of the double-position drill holes, upper high-position drill hole end holes of each set of high-position drill holes are away from the top plate by 30-40 m,and lower high-position drill hole end holes of each set of high-position drill holes are away from the top plate by 20-30 m; S4, coal seam and gas are subjected to pressure-releasing and extractionfrom the lower portions of extraction pipes to the interiors of hole sealing pipes inside the excavated drill holes; and S5, the contact positions of the extraction pipes and the drill holes are sealed through polyurethane. The double-position drill hole gas extraction technology is adopted, the extraction efficiency of the method is high, meanwhile the effective influence range of the drill holesis extended, the gas permeability of coal bodies is improved, the good condition is created for coal beam interior pressure releasing and gas releasing and flowing, and the low-gas-permeability coalseam pressure-releasing and gas-extraction method is easy to operate and good in extraction effect, and has wide practicability.

Description

technical field [0001] The invention discloses a pressure-relieving gas extraction method for a low-permeability coal seam, and specifically belongs to the technical field of coal mining. Background technique [0002] The mining of high-gassy and low-permeability coal seams is often accompanied by a large amount of gas gushing out, especially with the efficient intensification of coal production and the increase of mining depth, the amount of gas gushing out is increasing, and gas explosions and gas outbursts are dangerous. The threat is becoming more and more serious, and gas disasters have become the most important factor restricting the development of efficient and intensive mining technology and safe production. Therefore, how to effectively solve the problem of gas gushing in the process of mining high-gas coal seams is of great significance to the safe production of coal mines. [0003] To solve the problem of gas gushing in the process of mining high-gas and low-perm...

AI Technical Summary

Problems solved by technology

However, these methods all have the problems of small effective impact range of drilling, heavy drilling construction workload on the working face, and low extraction efficiency. It is necessary to adopt a method of pressure relief and permeability enhancement to expand the effective impact range of drilling and improve the coal seam drainage effect of gas.

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