A coal mine underground fracturing sealing device and method

Abstract

The invention provides an underground coal mine fracture sealing device and method. The underground coal mine fracture sealing device comprises a water injection pipe, a thick liquid return pipe, a front polyurethane hole sealing section, a back polyurethane hole sealing section, a safety valve, an umbrella type supporting device assembly and a thick liquid injection pipe. The umbrella type supporting device assembly is composed of an umbrella supporting frame, a supporting pipe, a sliding hoop, a piston rod and a piston, and a guide rail groove and the safety valve are arranged on the supporting pipe. When being fed into a drill hole, the umbrella type sealing device shrinks, and then the device is conveniently fed into the drill hole. When high-pressure water of which the initial injection pressure is 5MPa is injected, the umbrella type supporting device is opened, the piston is pushed forwards, the umbrella type supporting frame is unfolded and penetrates into coal, the high-pressure water continuously squeezes the hole sealing sections, and then the umbrella type supporting frame penetrates into the coal deeper and deeper. When the water injection pressure is increased to be larger than or equal to 15MPa, pressure water breaks through the safety valve to carry out fracturing operation on the drill hole, and therefore pressure loading capacity of the hole sealing sections is greatly improved, water injection pressure is increased, and the fracturing effect is improved. The underground coal mine fracture sealing device is simple in structure, easy to operate, high in pressure loading capacity, and good in sealing effect.

Description

technical field [0001] The invention relates to a drilling sealing device and method, in particular to a sealing device and method suitable for underground coal mine fracturing. Background technique [0002] The geological conditions of my country's coal mines are complex, high-gas coal seams account for 50-70%, and high-gas low-permeability coal seams account for about 70% of them. The mining of high-gassy and low-permeability coal seams is often accompanied by a large amount of gas gushing, especially with the efficient intensification of coal production and the increase of mining depth, the amount of gas gushing is increasing, and the threat of gas explosion and gas outburst is also increasing. Gas disasters have become the most important factor restricting the development of intensive mining technology and safe production in colleges and universities. Therefore, how to solve the problem of gas gushing in the process of mining high-gas coal seams is of great significance...

AI Technical Summary

Problems solved by technology

One of the technical difficulties is the high-pressure sealing of boreholes. For example, when high hydraulic fracturing is performed on coal seams, in order to form an effective fracture network inside the coal, for coal seams buried at a depth of 1000m, the sealing ability of boreholes needs to withstand water pressure above 30MPa. , otherwise there will be water leakage in the drilling and affect the fracturing effect

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