Method for extracting coal tunnel stripe coal bed gas based on controllable shock waves

Abstract

The invention provides a method for extracting coal tunnel stripe coal bed gas based on controllable shock waves. The method for extracting coal tunnel stripe coal bed gas based on the controllable shock waves comprises the steps that antireflective technological parameters of the controllable shock waves are determined in a geological unit where controllable shock wave anti-reflection is to be implemented; shock wave anti-reflection hole drilling is conducted on a coal bed or the coal bed bottom plate and top plate in the range of coal tunnel stripe in the bottom plate or the top plate extraction tunnel corresponding to the to-be-dug coal tunnel; coal slag or rock slag in drilled holes are discharged; casing pipes are lowered, and holes are solidified; a controllable shock wave generationdevice is lowered into a drilled hole to a target shock position through a drilling machine; and the shock wave anti-reflection drilled holes are sealed, the shock wave anti-reflection drilled holesare constructed by utilizing a controller of the controllable shock wave generation device outside the drilled holes, after the shock wave anti-reflection operation is completed, connected hole extraction is conducted on extraction drilled holes in the influence range of shock wave anti-reflection operation, and the gas extraction effect is improved. According to the method, the coal bed top plateand bottom plate are transformed into virtual storage layers with fracture development so that coal bed gas which is farther away from the extraction holes can be transported to the extraction holesthrough fractures in the top plate or the bottom plate and extracted out; the gas extraction time is shortened; and the extraction effect is improved.

Description

technical field [0001] The invention relates to the technical field of coal mine gas, in particular to a controllable shock wave-based gas extraction method for strip coal seams in coal roadways. Background technique [0002] The "Detailed Rules for the Prevention and Control of Coal and Gas Outbursts" requires that the coal seam gas in the strip coal seam gas of the pre-extraction coal roadway through the seam drilling is required to control the outside range of the recovery roadway: at least 20m outside the upper side contour line of the inclined and steeply inclined coal seam roadway, and at least 10m outside the lower side; other At least 15m outside the contour line on both sides of the roadway, such as figure 1 and figure 2 shown. In order to leave room for redundancy and strengthen production safety, some local coal supervision bureaus have required a wider scope of control on this basis. [0003] For the excavation of the coal roadway strip in the outburst coal s...

AI Technical Summary

Problems solved by technology

However, most of the outburst coal seams are soft coal seams with poor gas permeability, and the gas concentration decays rapidly when they are directly extracted, and the extraction effect is poor

[0004] like image 3 and Figure 4 As shown, the coal seam within a certain range on both sides of the coal roadway is controlled by the bottom extraction roadway through the layer-crossing drilling. Due to the influence of the poor air permeability of the coal seam, the effective extraction radius of the drainage hole is small, the density of the layer-crossing drilling is high, and the number of Many, large amount of work

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