Method for gas extraction through bedding directional long drill hole traversing working face in broken and soft coal seam

Abstract

The invention relates to a method for gas extraction through a bedding directional long drill hole traversing working face in a broken and soft coal seam. According to the method, through an air screwmotor directional drilling technology, the bedding gas extraction long drill hole is constructed in a tunneled roadway on one side of the working face of the coal seam, and the drill holes penetratesthrough a to-be-tunneled roadway on the other side of the working face to the position, within the control range of 15-20 m, of the outer side of the roadway; and after the drill hole is completed, adrill tool is lifted up, an open-close type guiding drill bit and a drill rod with a large through hole are put down, then a hole protection screen pipe is put down through the center of the drill rod, then the drill rod is lifted up, the screen pipe stays in the hole, and then a gas extraction pipeline is connected for gas pre-extraction. An air screw motor directional drilling method is adoptedin the gas treatment technology so that the drilling depth of bedding extraction of the broken and soft coal seam and the coal seam drilling-encounter rate can be greatly increased, invalid footagesare reduced in quantity, meanwhile the drill hole coverage range is ensured, the purpose of gas pre-extraction outburst elimination of the stope face and the to-be-tunneled roadway is achieved, and safe tunneling of the coal seam roadway and safe extraction of coal extraction work face are ensured.

Description

technical field [0001] The invention relates to a gas extraction method with long boreholes, which belongs to the technical field of gas control, and in particular to a method for gas extraction with long boreholes along the bedding direction of broken and soft coal seams crossing the working face. Background technique [0002] With the increase of coal mining depth and the expansion of mining scope, it is becoming more and more difficult to control coal seam gas with drilling drainage as the main technical means. In the soft and broken coal seam, gas drainage drilling is prone to collapse and sticking, and there is a problem that it is difficult to form a hole. At present, the rotary drilling method using air as the slag discharge medium or the rotary drilling method of large auger drill rods are generally used. Carry out drilling construction for gas drainage; while using rotary drilling, it is difficult to control the drilling trajectory, and it is easy to drill into the ...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of hole formation mainly based on depth and precision in the drilling construction of gas drainage in soft and broken coal seams, and to provide a kind of gas drainage of broken and soft coal seams that cross the working face along the bedding and directional long holes method

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