Multiphase medium plugging device and method for gas extraction drill hole

Abstract

The invention relates to a multiphase medium plugging device and method for a gas extraction drill hole, which are especially applicable to sealing of an underground coal mine layer-crossing drill hole and an in-layer gas extraction drill hole and determination of gas pressure. The multiphase medium plugging device is formed by an initial hole sealing section, a tail hole sealing section and a plurality of intermediate hole sealing sections, which are sequentially connected with one another, facilitates the adjustment on hole sealing depth and length and can realize 'fixed point' plugging of a mining-induced fracture zone. The multiphase medium plugging method comprising the steps of constructing the in-layer or layer-crossing gas extraction drill hole, placing the debugged and mounted multiphase medium plugging device into the gas extraction drill hole, filling cement mortar into the hole, and filling viscous liquid into the hole after the cement mortar is solidified. The multiphase medium plugging method and device provided by the invention achieve dual effects of solidifying and plugging the drill hole with the cement mortar and plugging fractures with the viscous liquid, and the pressured viscous liquid penetrates into the fractures of the drill hole to realize the regional plugging of in-situ and secondary fractures around the drill hole, thereby being beneficial to the improvement of a sealing effect of the drill hole. The multiphase medium plugging device provided by the invention is simple in structure, convenient to operate and good in using effect, and is safe and reliable.

Description

technical field [0001] The invention relates to a multiphase medium plugging device and method for underground gas drainage boreholes in coal mines, and is especially suitable for the sealing and gas pressure measurement of underground coal mine through-bed and coal seam gas drainage boreholes. Background technique [0002] As an associated product of coal, gas is not only the source of major gas disasters in coal mines, but also a valuable non-renewable energy source. With the increase of coal mining depth, the gas content of coal seams will increase significantly. Realizing coal and gas co-mining is an inevitable way to mine deep coal resources. At the same time, it is of great significance to improve the safe and efficient production level of coal mines and reduce greenhouse gas emissions. . [0003] At present, the pre-drainage of coal seam gas is the basic measure to realize the joint mining of coal and gas and reduce gas accidents, and the effective sealing of gas dra...

AI Technical Summary

Problems solved by technology

Up to now, most of the gas drainage boreholes are sealed with cement mortar, polyurethane and other sealing materials, but the crescent-shaped gap at the top of the borehole is very easy to appear in the cement mortar in the horizontal hole sealing, which is difficult to achieve when using polyurethane to seal the hole The length of the sealing section is longer, and the polyurethane is prone to shrinkage when it is used for a long time, and its use in coal mines is limited due to the toxicity of the material itself

[0004] Therefore, in the current gas drainage drilling sealing technology, the poor sealing quality directly leads to the low concentration of underground gas drainage in coal mines, shortens the effective period of drainage, and also reduces the effective utilization of gas drainage drilling. Rate

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