Gridding type layer-through drilling pore group permeability-increasing gas pumping method

Abstract

The invention relates to a grid type across-seam drilling hole multi-hole anti reflection gas extraction method. Grid type across-seam drilling hole positions are set in the coal seal area where the gas extraction is performed; the grid type across-seam drilling hole positions set are drilled with holes one by one, forming a hole group; when the hole drilling construction enters the coal seam, hole punching is performed by using high pressure water with 5 to10MPa water pressure and 10 m3 / h flow quantity to cause the drilling hole to spray holes, to form a crack between the coal seam hole and the hole, and to increase the coal seam permeability; after the drilling hole is penetrated through the coal seam of 0.5 m, the drilling hole is escaped from a drilling rod, and is inserted into a sealing tube for hole sealing. The drilling hole is connected with an extraction tube mesh through a sealing tube, a collecting tube, a gas collection tank and a branch tube, to perform gas extraction for the coal seam. The method leads the coal seam pre-drainage efficiency to be improved to over 40 percent from the original 20 percent, realizes safe, efficient and even extraction for the sole low permeability outburst coal seam, a high gas outburst dangerous coal seam is changed to be a low gas non-outburst dangerous coal seam, and the invention has a wide practicability.

Description

technical field [0001] The invention relates to a gas drainage method for increasing the permeability of a group of drilled holes in a grid pattern, and is especially suitable for the regional gas drainage of a single low-permeability outburst coal seam in a coal mine. Background technique [0002] With the increase of mining depth, the pressure and content of coal seam gas increase, the coal quality is soft, the gas permeability of coal seam is low, it is difficult to extract coal seam gas before mining, and the danger of coal and gas outburst is becoming more and more serious. my country has become the most serious outburst in the world. coal-producing countries. In order to eliminate the outburst danger of coal seams before mining and transform high-gas coal seams into low-gas coal seams, regional gas drainage methods are required. In the 1970s, our country successfully tested the regional gas extraction method in Tianfu Coal Mine and Zhongliangshan Coal Mine, which is to...

AI Technical Summary

Problems solved by technology

However, due to the low gas permeability of the coal seam, the extraction time of this method is long, and the gas extraction rate is low, which cannot meet the needs of efficient and intensive production in modern coal mines.

[0003] At present, the anti-permeability measures for a single low-permeability outburst coal seam mainly include deep hole pre-splitting blasting and hydraulic slotting. safety hazards, and the anti-reflection effect is limited, which cannot meet the needs of large-area gas pre-pumping