Drilling gas extraction method of Y-shaped ventilation high-level return airway in gob-side entry

Abstract

Disclosed is a method for extracting gas by drilling a hole in a gob-side entry retaining Y-type ventilation high-position return airway. The method comprises: constructing connection roadways (8) at intervals between a rail roadway roof extracting way (7) and a rail roadway (5); during stoping, building and filling a wall (9) along an edge of a gob (6) to retain the rail roadway (5), on a working face (2), inletting air by a haulage roadway (4) and the rail roadway (5) and returning the air by a retained way section of the rail roadway, the connection roadways (8), and the rail roadway roof extracting way (7), so as to form a gob-side entry retaining Y-type ventilation system, wherein the rail roadway roof extracting way(7) is used as a high-level return airway for secondary utilization; and respectively drilling a gas extracting hole (10) on adjacent gobs in the high-level return airway, and conducting gas extracting. By means of the present invention, the requirements of drilling for a retained roadway section can be lowered, and the mutual interference between the drilling and the working face stoping can also be avoided, so as to facilitate construction management; and simultaneously, because of the high-level return airway being away from the mining effect of the working face, the mining disturbance effect of drilling is lower than that of drilling holes in the front and back of the retained roadway, easy drilling maintenance is achieved, and efficient and long-term gas extraction can be achieved.

Description

technical field [0001] The invention relates to a coal mine gas extraction method, in particular to a method for drilling gas extraction in a gob-side entry Y-shaped ventilation high-position return airway suitable for safe mining of high-gas coal seam groups in deep wells. Background technique [0002] As a clean energy, gas should be mined and utilized. However, the occurrence of coalbed methane in most coal mining areas in my country has the characteristics of "three lows and one strong" of low pressure, low permeability, low saturation and strong heterogeneity. Coal and rock roadways use roadway + cross-layer drilling for gas extraction (referred to as roadway drilling method). This method is easy to implement in shallow mining, but it faces great difficulties in deep application: dedicated rock roadway for gas drainage (2-3 Article) Large amount of engineering, difficult layer control, high risk of excavation, unbalanced extraction, tense replacement of stopes, and poor ...

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Problems solved by technology

[0004] However, due to the large amount of deformation of the roadway in the gob-side entry retaining project of deep well and high ground pressure, especially the bottom heaving of the roadway, in order to control the deformation of the surrounding rock of the roadway, it is usually necessary to erect support components such as wooden piles and single hydraulic props in the roadway retention. It cannot meet the cross-section size requirements of drilling construction; at the same time, because the drill holes arranged in the retaining entry are close to the edge of the goaf, the disturbance effect of mining is strong, and the drilling is prone to cutting and plugging, and the gas drainage effect is difficult. ensure

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