Flexible Internal Control Rotary Directional Drilling System and Drilling Method for Underground Broken Coal Seam in Coal Mine

Abstract

A flexible internal control rotary directional drilling system and drilling method for underground soft coal seams in coal mines. The drilling system includes a flexible internal control rotary directional drilling tool, a directional system, an auger rod, an openable and closed drill bit and a double power head drilling rig. The flexible internal control rotary directional drilling tool is located between the auger rod and the openable and closable drill bit to realize rotary directional drilling. The directional system runs through the auger rod to measure the drilling trajectory. The dual power head drill It includes a large power head and a small power head to provide drilling power. The flexible internal control rotary directional drilling tool includes a flexible outer tube, a bent mandrel, a bearing set and a sleeve. The directional system includes an upper non-magnetic drill rod, Lower non-magnetic drill pipe, probe outer tube, measuring probe, cable inner tube and explosion-proof computer; thus, the present invention realizes the directional drilling and screen tube completion under the coal mine's broken soft coal seam drilling rotation mode. Hole protection, improve drilling safety and drilling efficiency, and then improve the coal seam drilling rate and gas drainage effect.

Description

technical field [0001] The invention relates to the technical field of underground drilling in coal mines, in particular to a flexible internal control rotary directional drilling system and a drilling method for broken soft coal seams in underground coal mines. Background technique [0002] At present, the drilling of the broken soft coal seam in the coal mine mainly adopts the rotary drilling construction of the helical, triangular and other heterogeneous structure drill pipes. Cause the drill hole to collapse. Due to the fact that the current rotary drilling technology cannot control the drilling trajectory, the coal seam drilling rate in the broken soft coal seam is low, and it is easy to cause the blind area of ​​the coal mining face, which seriously affects the safe and efficient mining of the broken soft coal seam. [0003] Downhole directional drilling conventionally uses hydraulically driven screw drilling tools, which is not suitable for broken soft coal seams. R...

AI Technical Summary

Problems solved by technology

Relevant personnel tried to use compressed air-driven power tools at the bottom of the hole to carry out sliding directional drilling in broken soft coal seams. The drilling of broken soft coal seams produces a large amount of powder, which needs to be stirred by special-shaped drill pipes and then carried out of the hole by compressed air. During sliding directional drilling, due to the non-rotation of the drill pipe, the pulverized coal is accumulated, which makes it difficult to build up the deflection and easily induces accidents in the hole

[0004] To sum up: the use of water as the powder discharge medium is not suitable for drilling in broken soft coal seams, and the sliding directional drilling method using compressed air as the powder discharge medium has the problems of difficulty in powder discharge and poor deflection effect

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