Segmented large-diameter screen pipes in underground directional long boreholes of coal mines and its running method

Abstract

The invention relates to a segmented large-diameter screen pipe in a directional long borehole underground in a coal mine and a running method thereof. It is composed of the female joints of screen pipes, and the remaining screen pipes are composed of male joints of screen pipes, throttling booster pipes, large-diameter screen pipes, and screen pipe female joints. The two sections of screens are hydraulically driven in the drill pipe to realize automatic connection through the male and female joints of the screens. When running in, the screens in the first section are hydraulically transported in place through the inner channel of the drill pipe, and then run into the subsequent screen sections. Subsequent segmented screens are also hydraulically transported in place and connected to the previous segment of screens through quick joints, and finally each segment of screens is connected in place to form a gas drainage channel with directional long holes; thus, the present invention uses segmented screens The method of running in solves the problems that the large-diameter screens with directional long boreholes cannot be run in place and the running efficiency is low, and the running efficiency is high, which also effectively guarantees the effect of gas drainage.

Description

technical field [0001] The invention relates to the technical field of borehole protection screen pipes for underground gas drainage in coal mines, in particular to a segmented large-diameter screen pipe in a coal mine underground directional long borehole with high-efficiency running into a large-diameter screen pipe and its running-in. method. Background technique [0002] my country's coal is mainly mined through mines. In recent years, a large number of shallow low-gas mines have gradually become high-gas mines with the increase of mining depth. How to control and utilize the gas well has become an urgent problem to be solved. Downhole drilling is the main way to control coal mine gas. The drilling methods mainly include ordinary rotary drilling and directional drilling. Ordinary rotary drilling was first applied in underground drilling. Directional drilling solved the problem of conventional drilling The existing problems such as uncontrollable drilling trajectory, li...

AI Technical Summary

Problems solved by technology

Due to the limitation of the structure of the directional drilling tool, it is impossible to directly use the traditional rotary drilling method to lower the screen pipe from the inner passage of the drill pipe after the directional drilling into the final hole.

There are two directions that people try to solve. One is to run the screen directly from the open hole after directional drilling into the final hole or use the push mechanism to run the screen pipe. The main problem encountered is that the drill hole is long and the open hole is run The resistance is large and the screen is easy to be damaged by push-pull and extrusion; the second is to re-run the reaming drilling tool and then run the screen from the inner diameter of the drill pipe after rotary reaming. Long boreholes (generally greater than 500m) will easily cause buckling effect of the screen pipe, and it is still difficult to run into the bottom of the hole

So far, neither attempt has been successful

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