Flexible hole protecting device and method for extraction drilling of broken soft coal seam

Abstract

The invention provides a broken soft coal seam extraction drilling flexible hole protection device and method. The device comprises a drilling tool system and a flexible hole protection system. During working, the drilling tool system conveys the flexible hole protection system to a preset position. The water injection supporting pipe is pushed, and the front-end fixing device extends out of a center hole channel of the drill bit. And the supporting claws are unfolded and embedded into a coal seam on the inner wall of the drill hole. And withdrawing the drilling tool system. The hydraulic pump injects high-pressure water into the water injection supporting pipe. And the water injection pressure-bearing water bag is pressurized and expanded. And the flexible hole protection bracket is expanded to support the drilled hole. And after extraction is completed, the flexible hole protection support is subjected to pressure relief and contraction. The flexible hole protection support can achieve rapid hole protection after hole drilling is completed; the expansion degree of the flexible hole protection support is determined by support elastic contraction force, injection water pressure and external hole protection stress, the support is dynamically balanced when the three forces reach balance, at the moment, the expansion degree of the flexible support is changed along with the change of the drill hole shape, and the flexible hole protection support adapts to different drilling links and is attached to the hole wall in real time.

Description

technical field [0001] The invention relates to the field of coal mine gas prevention and control, in particular to a flexible hole protection device and method for mining drilling in broken soft coal seams. Background technique [0002] Outburst broken and soft coal seams are widely distributed in my country. With the advancement of coal seam mining in my country, the characteristics of high in-situ stress and high gas pressure are becoming more and more obvious. Under the action of in-situ stress, gas pressure, tectonic stress and other factors, the surrounding hole wall is easily unstable, resulting in a series of damage forms such as borehole collapse and borehole deformation, which seriously hinders and affects the construction process of downhole drilling and Gas drainage efficiency, at present, the corresponding complete set of hole protection equipment is relatively scarce in China, and the hole protection technology under complex geological conditions is not yet matur...

AI Technical Summary

Problems solved by technology

[0002] Prominent broken soft coal seams are widely distributed in my country. With the advancement of coal seam mining in my country, the characteristics of high ground stress and high gas pressure become more and more obvious. The complex and changeable coal seam conditions have brought great challenges to coal seam drilling and hole protection Under the action of multiple factors such as ground stress, gas pressure, and structural stress, the surrounding hole walls of the borehole are prone to instability, resulting in a series of damage forms such as borehole collapse and borehole deformation, which seriously hinder and affect the construction process of downhole drilling and Gas drainage efficiency, the corresponding complete set of hole protection equipment in China is relatively scarce at present, and the hole protection technology under complex geological conditions is not yet mature. The hole range is small, the hole protection effect is limited, and it is difficult to form an effective gas migration channel, so that coal seam gas drainage faces a series of technical bottlenecks

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