Method for increasing extracting and drilling stability of low-permeability soft coal seam

Abstract

The invention relates to a method for increasing the extracting and drilling stability of a low-permeability soft coal seam. The method comprises the following steps of (1) sleeving the outer side ofa drill pipe with a telescopic trailing sleeve; (2) deeply drilling into the coal seam; (3) withdrawing the drill pipe and the telescopic trailing sleeve from a drilling cavity after drilling into thespecified depth; (4) putting an anti-collapse pipe in the drilling cavity to the bottom of the drilling cavity; (5) respectively fixing two flexible air bags to both ends of a hole sealing pipe, andconnecting the two flexible air bags through a ventilating pipe; (6) respectively fixing a grouting hose and a return hose to the upper and lower ends of the flexible air bag which is close to the drilling cavity; (7) sleeving the anti-collapse pipe with the hole sealing pipe, and inflating the two flexible air bags, so that the two flexible air bags are tightly abutted with the inner wall of thedrilling cavity; (8) grouting the sealed space between the two flexible air bags; and (9) removing a grouting device after grouting is completed, and tightening the grouting hose and the return hose.According to the method, the extracting and drilling stability is guaranteed, so that the problems of the low hole forming rate and the poor hole sealing effect of the soft coal seam are solved.

Description

technical field [0001] The invention relates to the field of borehole construction for gas drainage in underground soft coal seams in coal mines in the direction of mine ventilation and safety, in particular to a method for improving the stability of drainage boreholes in low-permeable soft coal seams. Background technique [0002] Coal and gas outbursts are a major threat to mine safety, and most mines in my country are gas outburst mines. Effective extraction of coal seam gas can not only prevent the occurrence of gas accidents, but also play a role in environmental protection if the extracted gas can be utilized. In recent years, Huainan, Jincheng, Yangquan and other mining areas have made many beneficial attempts and achieved some achievements in pre-mining coal seam gas extraction, extraction while mining, goaf extraction and fracture zone extraction. However, due to the relatively large proportion of soft coal seams in my country, and during the drilling construction ...

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Problems solved by technology

[0003] Based on the above problems, the present invention aims to provide a method with relatively simple structure and convenient operation, which can improve the porosity rate and sealing effect of soft and low-permeable coal seams, so as to ensure the stability of the drainage boreholes and solve the problem of soft and soft coal seam formation. Problems of low porosity and poor sealing effect

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