Method for extracting gas close to lower coal layer through directional drilling in thin coal seam fully-mechanized coal mining gob-side entry

Abstract

The invention provides a method for extracting gas close to a lower coal layer through directional drilling in a thin coal seam fully-mechanized coal mining gob-side entry. For a thin coal seam fully-mechanized coal mining face, through the mode of the gob-side entry, directional drilling is carried out in the entry to extract the gas close to the high-gas coal layer. Due to the mode of the coal mining face gob-side entry, in the thin coal seam exploiting process, the situations that the digging ratio is large, and digging replacement is tense can be relieved, the preparation time of the coal mining face is shortened, and the digging amount of a semi-coal stone drift can be reduced; on the other hand, directional drilling holes are drilled in the gob-side entry and can be distributed in the lower coal layer in a large drilling hole range mode due to directional drilling, the area of extracting the gas in the coal layer through the drilling holes is greatly increased, by means of extraction of directional drilling, the content of the gas close to the high-gas coal layer is reduced, and conditions are provided for safe, high-yield and high-efficiency mining of the lower coal layer. The method solves the problems that the gas of the high-gas coal layer poor in gas permeability is difficult to extract, the digging ratio of mining of the thin coal seam layer is large, the drivage ratio is large, and digging replacement is tense.

Description

technical field [0001] The method for gas drainage by directional drilling in gob-side entry of the present invention is especially suitable for gas drainage in adjacent low-permeability coal seams after directional drilling in gob-side entry entry and pressure relief in the process of fully mechanized mining in thin coal seams. Background technique [0002] Thin coal seam pressure relief mining and directional gas drainage technology is an important subject of coal mining technology. Many experts and scholars at home and abroad have done a lot of research on this and obtained some research results. The reserves of thin coal seams in my country account for about 20.4% of the total coal reserves, but the current mining of thin coal seams has problems such as large mining ratio, high driving rate, and tight mining replacement. For high-gas coal seams, the coal seam gas needs to be drained before mining to ensure that there are no potential safety hazards when mining high-gas c...

AI Technical Summary

Problems solved by technology

For high-gas coal seams, it is necessary to drain the coal seam gas before mining to ensure that there are no safety hazards when mining high-gas coal seams. Drainage roadway, arrange drilling holes in the drainage roadway to extract gas from high-gas coal seams, because this method needs to arrange a separate rock roadway, so there are problems such as high cost and complicated process

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