Method for bedding drilling and working surface gas pre-extraction

Abstract

The invention discloses a method for bedding drilling and working surface gas pre-extraction. According to the extraction time difference and the difference in distances to the cut openings, downward bedding drilled holes with different hole distances are parallelly constructed along the tendency of a coal seam respectively in working surface air returning following grooves, upward bedding drilled holes with different hole distances are parallelly constructed along the tendency of the coal seam in working surface conveying following grooves, gas extraction pipelines are respectively arranged on the sides of the conveying following grooves and the air returning following grooves close to a working surface coal wall, the downward bedding drilled holes and the upward bedding drilled holes of the conveying following grooves and the air returning following grooves enter a mine gas extraction system through the gas extraction pipelines, and after grouting and hole sealing, the extraction system is in combination to perform gas extraction. According to the technical scheme, by adjusting a drilling arrangement mode, the bedding drilled holes with different hole bottom distances are constructed according to the extraction time difference and the difference in distances to the cut openings, the drilling engineering quantity is reduced, production time of the working surface is shortened to the largest extent, the gas extraction effect is improved, and coal and gas simultaneous extraction is achieved.

Description

technical field [0001] The invention belongs to the field of mining, and more specifically, the invention relates to a method for pre-extracting gas from a working face by drilling along layers. Background technique [0002] Coal mining faces with high gas or outburst coal seams that need to be put into production quickly must eliminate or reduce the coal seam content to prevent abnormal gas dynamic phenomena during the mining process of the mining face. Using drilling to pre-extract coal seam gas is one of the main measures for regional outburst prevention , Pre-drainage drilling is divided into two types: through-bed drilling and bedding-based drilling. Among them, bedding-based drilling has become the most basic form of gas extraction due to the high utilization rate of drilling holes. Most of the coal seams in coal and gas outburst mines belong to Low permeability soft coal seam, for low permeability coal seam, the range of gas flow field controlled by each drilling hole...

AI Technical Summary

Problems solved by technology

[0002] Coal mining faces with high gas or outburst coal seams that need to be put into production quickly must eliminate or reduce the coal seam content to prevent abnormal gas dynamic phenomena during the mining process of the mining face. Using drilling to pre-extract coal seam gas is one of the main measures for regional outburst prevention , Pre-drainage drilling is divided into two types: through-bed drilling and bedding-based drilling. Among them, bedding-based drilling has become the most basic form of gas extraction due to the high utilization rate of drilling holes. Most of the coal seams in coal and gas outburst mines belong to Low permeability soft coal seam, for low permeability coal seam, the range of gas flow field controlled by each drilling hole is very small, with the increase of time, the increase of the flow field range is not obvious, in this case, drilling Hole spacing is more important to increase the amount of gas drainage, but blindly increasing the density of boreholes will inevitably increase the amount of drilling construction, prolong the construction period, and affect economic benefits; it is very difficult to construct long boreholes for gas drainage in soft coal seams , it is prone to defects such as hole collapse or stuck drill, which will affect the gas concentration in the extraction; because the coal seam with a long distance from the cutting hole is mined for a long time, it has a longer extraction time; if the same method is used with The distance between the drill holes arranged in the coal seam which is closer to the cutting hole not only increases the construction volume of the drilling hole and the movement of the drilling rig, prolongs the construction period and increases the construction cost, but also increases the risk of hole collapse and drill sticking during the drilling process. The possibility of defects such as the occurrence of defects; reasonably determining the relevant parameters of long boreholes along the bedding is the basis for achieving higher drainage effects and better economic benefits. Among the parameters, hole bottom spacing and drainage time have a greater impact on the drainage effect; for bedding drilling drainage, the drainage time is mainly affected by the production arrangement, and the range of adjustment is limited, but the distance from the cut hole With different distances, the actual extraction time of the boreholes varies greatly, and the extraction effect is also different; relatively speaking, the spacing of the boreholes has a greater impact on the extraction effect, and it is easier to adjust

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