Coal-mine broken-soft-coal-seam flexible internal control rotary directional drilling system and method

Abstract

The invention discloses a coal-mine broken-soft-coal-seam flexible internal control rotary directional drilling system and method. The drilling system comprises a flexible internal control rotary directional drilling tool, a positioning system, a spiral drill pipe, an openable drill bit and a double-power-head drilling machine; the flexible internal control rotary directional drilling tool is located between the spiral drill pipe and the openable drill bit to achieve rotary directional drilling, the positioning system penetrates the spiral drill pipe to have drilling traces measured, the double-power-head drilling machine includes a large power head and a small power head to provide drilling power, the flexible internal control rotary directional drilling tool comprises a flexible outer pipe, a core bending shaft, a bearing pack and a sleeve, the positioning system comprises an upper non-magnetic drill pipe, a lower non-magnetic drill pipe, an outer exploring pipe, a measuring exploring pipe, a cable-through inner pipe and an explosion-proof computer. By the arrangement, directional drilling and hole protecting of a sieve pipe are realized in a coal-mine broken-soft-coal-seam rotary drilling mode, drilling safety and drilling efficiency are improved, and coal seam drilling-encounter ratio and gas extraction effect are thereby improved.

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

Images