Broken soft thin coal seam gas extraction directional long drilling construction drilling tool assembly and method

Abstract

The invention discloses a broken soft thin coal seam gas extraction directional long drilling construction drilling tool assembly and method, and belongs to the field of coal mine underground gas extraction. The broken soft thin coal seam gas extraction directional long drilling construction drilling tool assembly comprises a drilling rod and a transmission shaft, a drill bit A is arranged at one end of the transmission shaft, a drill bit B is arranged outside the drill bit A, the drill bit B comprises at least two combination blocks, guide grooves are formed in the combination blocks, at least two sliding grooves are formed in the outer wall of the transmission shaft, and sliding blocks A are slidably connected to the lower sides of the interiors of the sliding grooves; an extension assembly penetrates through the middle of the sliding block A. By means of the supporting rod and the extending assembly, the combined blocks can be moved when the lead screw rotates the sliding block B to move downwards, then the drill bit A can leak out of the middles of the two combined blocks after ascending, then the drill bit can be replaced quickly and conveniently, and the drill bit does not need to be replaced after a drilling tool is taken out of a coal seam.

Description

technical field [0001] The invention relates to the field of underground gas drainage in coal mines, and more particularly, to a drilling tool assembly and method for directional long drilling construction for gas drainage in crushed and soft thin coal seams. Background technique [0002] Thin coal seams are widely distributed in my country, mainly referring to coal seams with a thickness of less than 1.3m, accounting for about 20% of my country's coal reserves. In order to improve the recovery rate of coal, my country stipulates that coal seams with thickness greater than 0.8m must be mined, and coal seams with thickness less than 0.8m are encouraged to be mined. However, gas control in broken, soft and thin coal seams has become the main problem restricting its safe and efficient mining, because the gas drainage drilling holes in broken and soft thin coal seams have shallow hole depth and low porosity. Among them, different drill bits are required to drill to different le...

AI Technical Summary

Problems solved by technology

However, gas control in broken soft and thin coal seams has become a major problem restricting its safe and efficient mining, because the drilling depth of gas drainage in broken and soft thin coal seams is shallow and the porosity rate is low

Among them, different drill bits need to be used when drilling to different layers in the drilling process, and when replacing the drill bit, it is necessary to take out the drill tool from the coal seam before replacing it. At this time, the drilled hole is easy to collapse as the drill tool is taken out. , so it needs to be drilled again, which is not only troublesome to replace, but also affects work efficiency

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