Layered hydraulic fracturing method of underground coal mine multiple coal seams

Abstract

The invention discloses a layered hydraulic fracturing method of underground coal mine multiple coal seams. The layered hydraulic fracturing method of the underground coal mine multiple coal seams is suitable for layered air-permeability-increasing operation in soft and low-air-permeability coal seam groups and includes the following steps: (1) punching a hydraulic fracturing drilling hole penetrating all coal seams; (2) installing a coal seam hydraulic fracturing sleeve pipe in the hole, and then fixing the hole to the bottom with cement paste; (3) in the mode of hole sealing with capsules, sealing the hole to a top plate of the coal seam to be fractured, and then through a high-pressure sealing drill rod, sending a special perforating gun to the coal seam to be fractured in the hole; (4) calibrating the position of the perforating gun, aiming at the coal seam to be fractured, through the high-pressure sealing drill rod, pumping perforating liquid to the perforating gun to shoot through the sleeve pipe and a cement sheath, and a perforating orifice is formed in the coal seam; (5) taking the perforating gun and the high-pressure sealing drilling rod out of the sleeve pipe; (6) leading high-pressure water in the sleeve pipe to carry out hydraulic fracturing on the coal seam in the position of the perforating orifice; and (7) after a coal seam is fractured, repeating the steps (3) to (6) to carry out hydraulic fracturing on a next coal seam until all the coal seams are fractured. Effective pressure relief and air-permeability increasing in layered coal seam groups can be achieved, and the method of the underground coal mine multiple coal seam layered hydraulic fracturing is simple, good in effect and low in cost.

Description

technical field [0001] The invention relates to a layered hydraulic fracturing method for multi-coal seams in underground coal mines, which belongs to the technical field of gas control in underground areas of coal mines, and is especially suitable for pressure relief and permeability enhancement of coal seam groups. Background technique [0002] Gas drainage is an important means to prevent gas disasters and realize comprehensive utilization of gas. However, for coal seams with low permeability and low gas permeability, the drainage rate of existing technologies cannot meet the requirements of gas disaster control and comprehensive utilization. Therefore, it is imperative to develop an economical and efficient gas drainage technology to achieve efficient gas drainage from low-permeability coal seams. Hydraulic fracturing is a new technology that integrates regional and local gas control to meet this production demand. This process is to transplant the conventional process ...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the shortcomings of single coal seam hydraulic fracturing technology for pressure relief and permeability enhancement of multiple coal seams, improve the gas drainage effect of multi coal seams, and provide a multi-coal seam layered hydraulic fracturing method in underground coal mines, which can maintain Under the condition that the number of drilling holes remains unchanged, all the coal seams that need hydraulic fracturing are relieved to increase permeability. At the same time, the effect is obvious, the cost is low, and the construction efficiency is high.

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