Sealing method of high sealing quasi-horizontal drilling hole

Abstract

Disclosed is a sealing method of a high sealing quasi-horizontal drilling hole, which is particularly applied to the operation of mechanical grunting and sealing of a quasi-horizontal drilling hole in underground coal mines. The sealing method of the invention adopts a way of two-stage grunting to seal a quasi-horizontal drilling hole. For a gas drainage hole, the steps are: first plugging the front end and the rear end of a gas drainage pipe by using a bagged double composite sealing material, then starting a grunting pump and pumping seriflux of the sealing material into the gas drainage hole through a first time grunting pipe; waiting until the seriflux grunted at the first time is solidified and an interspace emerges on the upper portion of the gas drainage hole because of the self contractility of the grunted seriflux; and pumping the seriflux of the sealing material a second time into the interspace on the upper portion of the gas drainage hole and the fractured coal body adjacent to the hole through a second time grunting pipe. The sealing method provided by the invention enables the grunted seriflux to effectively seal the inner space of a drilling hole and the fractured coal body surrounding the hole, realizing the maximization of space and crack sealing and meeting the requirement of high sealing. Besides, the sealing method merits in easy operation and low cost.

Description

technical field [0001] The invention relates to a method for sealing near-horizontal boreholes with high sealing performance, especially suitable for the sealing of near-horizontal boreholes for various purposes in underground coal mines, such as pressure measurement boreholes for identification of coal and gas outburst risks, high-pressure pulsation orientation Sealing of drilling holes such as hydraulic fracturing drilling and gas drainage drilling. Background technique [0002] my country's coal mine gas geological conditions are complex, of which high-gas coal seams account for 50%-70%, and low-permeability coal seams account for about 70% of them. Therefore, during the mining process of coal mines, coal and gas outburst risk identification is often required, as well as some regional gas prevention and control measures, such as high-pressure pulsating directional hydraulic fracturing, deep hole loosening blasting, hydraulic slotting, and advanced drilling. At the same t...

AI Technical Summary

Problems solved by technology

At the same time, most of the above work must be carried out in the drilling hole sealing operation, and the near-horizontal drilling is a type of drilling that is difficult to seal. It is self-shrinking and often forms a "crescent"-shaped void in the upper part of the hole. For example, when high-pressure pulsating directional hydraulic fracturing is performed underground, the high-pressure water injected into the coal body frequently flows out from the upper part of the hole.

In this case, it is difficult to effectively seal the cracked area in the upper coal wall of the borehole, which greatly reduces the sealing effect, which causes great difficulties for outburst identification and mine gas prevention and control.

In response to this technical problem, some researchers have proposed the method of adding expansion agent to the cement mortar material, but in actual operation, this method cannot achieve the desired effect, and the upper void in the hole still exists

If the drilling cannot be sealed with high quality, it will affect the effect of various subsequent works

In order to solve the technical problem of low sealing performance of mechanically cemented mortar sealing near-horizontal drilling, it is necessary to study a new sealing method with high sealing performance to meet the requirements of on-site coal and gas outburst risk identification and mine gas prevention and control. urgent need

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