Drilling and sealing method and sealing device for ultra-high pressure fracturing holes in underground coal mines

Abstract

The invention discloses a drilling-sealing method and a sealing device of a coal mine underground ultrahigh pressure fracturing hole. The drilling-sealing method comprises the following steps: drilling a plugging hole on coal rock body; going on drilling a fracturing hole forward in the plugging hole; transmitting the sealing device into the plugging hole, enabling a water outlet hole of a fracturing pipe to stretch into the fracturing hole and enabling a taper sleeve sleeved on the fracturing pipe and made of soft material to plug on a hole opening of the fracturing hole; sealing by using polyurethane and solidifying for 30 minutes for 1 m length section at the hole opening of the plugging hole; and grouting cement slurry greater than 425 into the plugging hole with pressure by a grouting pipe, and solidifying for 48 hours after finishing grouting. The device comprises a grouting pipe and a slurry returning pipe and a fracturing pipe. The grouting pipe and the slurry returning pipe are arranged in the plugging hole. The grouting pipe, the slurry returning pipe and the fracturing pipe are connected integrally. A soft taper sleeve is arranged on the fracturing pipe. The soft taper sleeve is plugged at the hole opening of the fracturing hole. The invention has the advantages that the sealing method has high sealing success rate, good effect and wide application range; and the sealing device has simple structure and convenient operation.

Description

technical field [0001] The invention relates to the technical field of coal seam gas drainage, in particular to a drilling and sealing method for ultra-high pressure fracturing holes in underground coal mines and a hole sealing device used in the hole sealing method. Background technique [0002] Coal seam gas is a kind of clean energy, but it is also a source of disaster for coal mine production. How to achieve the pre-extraction of gas before coal mining, to achieve the dual purpose of resource development and utilization and coal mine disaster reduction, has always been the focus of attention. Especially with the increase of mining depth, the increasingly strong demand for resources, and the introduction of a series of national compulsory measures on coal mine gas disaster management and the introduction of incentive policies for the development and utilization of coalbed methane, there is an urgent need to have a set of systematic, complete, ground-to-underground Combin...

AI Technical Summary

Problems solved by technology

The drilling depth of the plugging hole in this way can reach 15m~50m, the diameter can be controlled at about 100mm, and the diameter of the fracturing hole can be controlled at about 80mm. However, the main problem of this plugging method is that when the grouting pressure increases When it reaches a certain level, the cement slurry will flow into the fracturing hole from the opening of the fracturing hole, causing the water outlet hole at the front end of the fracturing tube to be blocked, thereby affecting the fracturing effect

When the grouting pressure is high enough, the cement slurry will even enter the pressure pipe and block the fracturing pipe hole, resulting in the failure of fracturing

Images