Entitative coal seam gas drainage drilling hole double-pipe drainage method

Abstract

The invention provides an entitative coal seam gas drainage drilling hole double-pipe drainage method, which is particularly applicable to a coal mine underground entitative coal seam long-distance and large-aperture gas drainage drilling hole. A gas drainage pipe is sent into the drainage drilling hole to the hole bottom, a flexible sleeve pipe with the diameter being twice the diameter of the gas drainage pipe is sheathed at the back part of the gas drainage pipe, a 3-4m pattern hole is formed at the front end of the flexible sleeve pipe, a first polyurethane double-material hole sealing bag and a second polyurethane double-material hole sealing bag are respectively and fixedly arranged in positions with distances being 4 to 5m and 22 to 23m from the front end of the flexible sleeve pipe by adhesive tapes, and the flexible sleeve pipe is sent into the drainage drilling hole after the hole sealing bags are extruded so that the second polyurethane double-material hole sealing bag is 2 to 3m away from the hole opening of the drilling hole; after the polyurethane is cured, cement mortar is filled between the two polyurethane hole sealing sections; and after the cement mortar is cured, the flexible sleeve pipe is connected into a gas drainage net for gas drainage. The method has the advantages that the structure is simple, the operation is convenient, and the problem of gas drainage flow rate reduction can be effectively solved.

Description

technical field [0001] The invention relates to a double-pipe drilling method for gas drainage in the coal seam, and is especially suitable for long-distance and large-diameter gas drainage drilling in the coal seam under the coal mine. Background technique [0002] my country's coal and gas outburst disasters are serious, which poses a threat to the safe production of coal mines. Gas drainage in this coal seam is one of the effective means to eliminate gas hazards and ensure gas utilization. In order to increase the gas drainage space and realize efficient gas drainage, long-distance and large-diameter boreholes are often constructed in this coal seam. However, with the increase of mining depth, the ground stress and gas pressure continue to increase, and the large-diameter borehole will be seriously deformed and collapsed under the action of radial load, and even large-scale blockage of broken coal will occur in the stress concentration area. Regardless of the blinding s...

AI Technical Summary

Problems solved by technology

After the on-site construction of the coal seam drainage boreholes, the phenomenon of low gas drainage flow rate and rapid decline often occurs. The life of the drainage boreholes is short, and it is difficult to effectively extract the gas from the coal seam, which greatly restricts the development of coal and gas co-extraction technology.

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