Gas extraction center divided-flow type grouting and hole sealing device and hole sealing method

Abstract

The invention discloses a gas extraction center divided-flow type grouting and hole sealing device which comprises an extraction pipe, a grouting plug, a left bag and a right bag, wherein the extraction pipe penetrates through the left bag and the right bag, a multifunctional valve is arranged in the extraction pipe, and the left side and the right side of the multifunctional valve are respectively connected with a left flow division pipe and a right flow division pipe; the left flow division pipe and the right flow division pipe are both sheathed on the extraction pipe, and the inner diameter of the left flow division pipe and that of the right flow division pipe are both greater than that of the extraction pipe so as to form a slurry passage among the left flow division pipe, the right flow division pipe and the extraction pipe; and a grouting insertion pipe is inserted into the extraction pipe. Through the gas extraction center divided-flow type grouting and hole sealing device, more effective grouting and hole sealing of drilling holes in the hole sealing section can be realized, and the generation and the propagation of leakage cracks around the drilling holes can be better prevented. The invention also provides a hole sealing method by using the gas extraction center divided-flow type grouting and hole sealing device. Through the method, high stress regions are produced around the drilling holes in the hole sealing section, the permeability of coal around the drilling holes in the hole sealing section is reduced, and the purpose of effectively grouting and sealing the drilling holes in the hole sealing section is realized.

Description

technical field [0001] The invention relates to a hole-sealing device and a hole-sealing method for coal mine gas drainage drilling, in particular to a hole-sealing device and a hole-sealing method suitable for permanent hole sealing of coal seam holes in underground coal mines. Background technique [0002] The depth of underground drainage drilling is generally 50 meters to hundreds of meters, and only a certain distance from the hole is sealed. It is difficult to seal the hole by direct grouting except for inclined drilling. The sealing of gas drainage boreholes is divided into permanent sealing and temporary sealing. At present, the known permanent sealing of drilling holes for gas drainage in this coal seam uses foamed polyurethane, foamed cement and other foaming materials as sealing materials. The early "cement roll sealing device" (ZL90227075.3) It is no longer used. The direct grouting and sealing method for drilling is only suitable for inclined drilling. At prese...

AI Technical Summary

Problems solved by technology

The applicant's invention of "Bag Grouting Sealing Device and Its Hole Sealing Method" (ZL200710054384.5) has the following defects: First, for grouting outside the pipe, two pipes must be inserted into the drill hole side by side, which limits the sealing pipe. diameter, the resistance of gas extraction increases; second, the grouting between the two bladders relies on the spring ball check valve to control the opening pressure, and the spring ball check valve has a grouting pressure drop, resulting in two bladders The grouting pressure between the pockets is lower than the grouting pressure of the two pockets, which affects the quality and effect of sealing; third, the spring ball check valve is affected by the damp environment in the well, and the opening pressure changes greatly, resulting in sealing The success rate of the hole is reduced

The applicant invented the "secondary high-pressure grouting sealing device and its sealing method for gas drainage" (ZL200910064186.6). The sealing process is cumbersome; second, after the first grouting to the bladder, dripping will inevitably occur at the grouting port, and the dripping grout needs to be rinsed with clean water. Improper flushing will lead to difficulty in the grouting plug during the second grouting. Insertion, resulting in the failure of the secondary grouting; third, structurally limits the length of the drilled grouting section between the two pockets, affecting the sealing effect

In addition, the two technologies previously invented by the applicant (ZL200910064186.6 and ZL200710054384.5) also have a common defect, that is, the bundling at both ends of the pouch is done externally, and the tear resistance of the bundling is less than that of the pouch The cracking ability cannot give full play to the grouting expansion effect of the bag, and the reliability of bundling is not high

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