Down hole continuous screen pipe hole protection method for coal mine

Abstract

The invention belongs to the technical field of coal mine safe production and particularly provides a down hole continuous screen pipe hole protection method for a coal mine. The method comprise the following steps that testing devices such as a drilling machine and a screen pipe conveying device and materials are transferred to a drilling construction site, a cylindrical reeling disc is reeled with a continuous screen pipe, and a hole clamping device is installed at the end of the screen pipe conveying device; drilling is conducted on a soft coal construction consequent layer or penetrating layer; after drilling is conducted to the position of a designed depth, drilling is stopped, and the screen pipe conveying device is installed on the drilling machine; the continuous screen pipe and the hole clamping device are inserted into the screen pipe conveying device, and the continuous screen pipe is conveyed into a drilling rod through the conveying device; a lower screen pipe drill bit is ejected away through the hole clamping device at the end of the continuous screen pipe, and the screen pipe is fixed to the wall of a drill hole; the continuous screen pipe is cut off at a hole mouth, and the drilling rod is withdrawn; and hole sealing continuous pumping is conducted through a large-diameter sleeve pipe. According to the down hole continuous screen pipe hole protection method for the coal mine, in soft coal drilling, the screen pipe putting in time is short, efficiency is high, the compression strength of the screen pipe is high, drill hole gas extraction efficiency is high, drill hole pumping and discharging efficiency are sufficiently improved, the gas pre-pumping time is shortened, and gas disasters are eliminated to the utmost extent.

Description

technical field [0001] The invention belongs to the technical field of coal mine safety production, in particular to a method for protecting holes of continuous screen pipes in underground coal mines. Background technique [0002] Researches at home and abroad have shown that when drilling soft coal seams, the exposed area of ​​coal increases greatly, and a large amount of adsorbed gas is decomposed from micropores and enters large pores and cracks, and is released from the exposed surface around the hole wall together with free gas. At the same time, due to the interconnection of various pore spaces around the hole wall, a large amount of gas stored in the coal seam will quickly diverge and flow to the borehole under the action of the pressure gradient, and the soft coal seam has low elastic modulus, high Poisson's ratio, and high brittleness. , Easy to break, so that the hole diameter becomes smaller, the hole collapses, the gas channel becomes smaller, and it is blocked. ...

AI Technical Summary

Problems solved by technology

Follow pipe drilling is an engineering drilling technology for surface wells and complex formations. It is expected to further solve the problem of soft coal collapse when it is introduced into the field of soft coal drilling technology. However, the existing technological process is too complicated to be popularized and applied underground, and further research is needed. and improvement; the technology of running the screen inside the drill pipe is relatively simple, and it is currently used in downhole to some extent. However, since the existing screens are 1-2m per root, the screens are connected by joints, and the screens need to be manually connected before drilling. In-rod transportation, there are problems such as low screen efficiency, high labor intensity of workers, low compressive strength of screens and small inner diameter of screens, etc.

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