Method for welding well ground pipeline for gas extraction in mining area

Abstract

The invention discloses a method for welding a well ground pipeline for gas extraction in a mining area. The method comprises the specific steps that A, a water stop isolation strip is installed at the extending-in end of a gas guiding pipe (6); B, the extending-in end of the gas guiding pipe (6) is inserted into a mining well casing (1), the water stop isolation strip is made to be tightly attached to the mining well casing, and the length of the portion, led out of the ground, of the gas guiding pipe (6) is not smaller than 5 m; C, slurry or water is fed into the mining well casing (1) from an end port of the mining well casing (1), it is guaranteed that the depth of the slurry or the water above the water stop isolation strip is not smaller than 2 m, and then a liquid blocking layer (4) is formed; D, a flange (5) is welded to the end port of the mining well casing (1); E, the depth of the slurry or the water above the water stop isolation strip is kept not smaller than 2 m in the welding process; F, after welding of the flange, the gas guiding pipe (6) is taken out of the mining well casing (1). By the adoption of the method for welding the well ground pipeline for gas extraction in the mining area, the safety of welding of the ground well mouth pipeline is guaranteed in the presence of gas in the mining area, and the method is suitable for maintenance or refitting of the well mouth pipeline in the mining area.

Description

technical field [0001] The invention relates to a welding method for a surface pipeline of a gas drainage well in a mining area, and belongs to the technical field of gas drainage. Background technique [0002] In some mining areas, coal seams are threatened by coal and gas outbursts, and coal mining requires gas drainage to eliminate outbursts. Coal seams in most mining areas in my country are characterized by softness, low gas permeability, high gas content, and high pressure. Gas drainage is difficult, which seriously affects mine safety production. The wells in the ground mining area take advantage of the favorable opportunity for the pressure relief of the upper coal seam caused by the mining of the lower coal seam coal mining face, and the gas accumulation in the goaf of the lower coal seam working face and the analytical gas of the upper coal seam pressure relief are used to effectively control coal mine gas disasters. At the same time, it is an important method to m...

AI Technical Summary

Problems solved by technology

As the wells in the mining area continue to overflow with gas, the gas is prone to combustion or even explosion when it encounters open flames, high temperature, static electricity, etc. The ground wellhead well pipe cannot be welded

Because the prior art does not have a method for safely completing the above-mentioned welding operations, sometimes the wells in the mining area can only be blocked and scrapped, and the wells in the mining area can be re-excavated from another place for gas drainage, thereby improving the mine's safety. Production costs reduce production efficiency and affect mine production safety

Images