Coal mine downhole hydraulic jet tree-shaped drill hole way-type drilling unit

Abstract

The invention relates to a coal mine downhole hydraulic jet tree-shaped drill hole way-type drilling unit. The drilling unit comprises drill rod, a guider, a drill bit, a high-pressure hose, a self-propelled drill bit and a dial. The drill rod is in threaded connection with the front end of the guider. The drill bit is in threaded connection with the tail end of the guider. The drill rod, the guider and the drill bit are used in cooperation, and the two steps of broaching and guider feeding-in can be finished at the same time. After broaching is finished, the high-pressure hose and the self-propelled drill bit are used for drilling tree-shaped drill holes in a coal seam. The distribution uniformity of the tree-shaped drill holes is controlled by the dial. The main effect of the drilling unit is to drill main holes of the tree-shaped drill holes of the coal seam and the tree-shaped drill holes, and uniform permeability increase of the coal seam is achieved. The drilling unit is simple in structure, convenient to operate and suitable for drilling the tree-shaped drill holes in the gas extraction process of the low-air-permeability coal seam.

Description

technical field [0001] The invention relates to the underground drilling technology of coal mines, in particular to a drilling tool used for self-advancing drilling into tree-shaped drilling holes in the gas drainage process of low-permeable coal seams. Background technique [0002] Many coal seams in my country have the characteristics of low permeability, etc., and conventional methods are difficult to effectively extract gas from coal seams with low permeability. How to increase the air permeability of coal seams is the key to solving the problem of gas drainage in low permeability coal seams. [0003] As an effective reservoir permeability enhancement technology, hydraulic technology provides a feasible method to solve the problem of low permeability of coal seam, and is an effective way to increase the permeability of coal seam. Hydraulic technology uses high-pressure water as the driving force to expand and extend the original cracks in the reservoir or artificially fo...

AI Technical Summary

Problems solved by technology

Although the existing reaming drill bits in coal mines can drill holes that meet the requirements, because the drilling and guide are sent separately, it often takes a lot of time and increases the workload. There may also be holes

[0005] In addition, the current guide is unreasonable in the design of the guide track. First, there is usually only one curvature, and it is difficult for the high-pressure hose to turn; second, the width of the steering guide track is not properly designed. The drill bit is stuck, and if it is too large, it will not be able to play a practical restraint role

In addition, the current guider does not consider the problem of slag discharge when drilling into tree-shaped holes. The annular space of the guider is small and the slag cannot be discharged smoothly, which affects the smooth advancement of the drill bit.

[0006] In addition, self-propelled drill bits are required for hydraulic jet tree drilling in coal mines, and self-propelled drill bits need to cooperate with guides. The current drill bits have the following problems: 1) The drill bit or nozzle has a complex structure, large size, and poor steering ability. Short service life; 2) The efficiency of water jet rock-breaking drilling is low during long-distance drilling; 3) The drilled holes are small in size, easy to jam the drill bit, and difficult to remove slag; The rock effect is poor, and it is easy to form a boss in the center of the drill hole, which hinders the advancement of the drill bit; 5) The self-progressive force generated by the drill bit is small, the hole trajectory is difficult to control, and it is easy to drill off the hole

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