Method for coal uncovering in cross cut by hydrothermal coupling based coal fracturing

Abstract

The invention discloses a method for coal uncovering in a cross cut by hydrothermal coupling based coal fracturing. The method includes: sequentially constructing a main fracturing hole, branched fracturing holes and guide holes in a rock stratum roadway section, wherein the main fracturing hole is formed in the center of an equilateral triangle, hole starting positions of the branched fracturing holes are arranged at three vertexes of the equilateral triangle while hole finishing positions of the same meet at a central line of the equilateral triangle, the guide holes are positioned on a circle taking the main fracturing hole as a circle center and with radius of 5-15m, and herein fracturing equipment comprises water injection equipment composed of an intelligent water tank and a fracturing pump and a powder injector; injecting quicklime powder in the powder injector into the main fracturing hole and the branched fracturing holes through underground air pressure; hydraulically fracturing the main fracturing hole through the water injection equipment, wherein the quicklime powder carried by high-pressure water enters fractures and thermally reacts with water to generate a lot of heat to realize coal uncovering in the cross cut through hydrothermal coupling based coal fracturing. By the method, ground stress and gas pressure of pre-uncovering coal seams are lowered, safety effect is remarkable, and cost is low.

Description

technical field [0001] The invention relates to a method for uncovering coal at stone gates of coal bodies based on hydrothermal coupling fracturing, which belongs to the technical field of coal mining at underground coal mines, and is especially suitable for high-risk coal uncovering operations at deep high-gas outburst coal seams. Background technique [0002] The geological conditions of my country's coal mines are complex, high-gas coal seams account for 50%-70%, and high-gas low-permeability coal seams account for about 70% of them. The occurrence characteristics of high gassy and low permeability coal seams in my country are microporosity, low permeability and high adsorption. With the increase of mining depth, the amount of gas gushing out and the stress of the coal seam are getting bigger and bigger, which leads to the threat of coal and gas outburst when the coal is unearthed in Shimen is becoming more and more serious. Therefore, coal mines often need to carry out ...

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Problems solved by technology

[0003] For many years, my country's coal mines have been studying how to prevent the outburst of coal and gas when the coal is uncovered in Shimen, and try to eliminate the danger of coal outburst in Shimen. A series of measures such as holes and even coal mining and rock removal have been taken, but the phenomenon of coal mining in Shimen still occurs from time to time, and even the protrusion of different delay times has occurred, resulting in serious losses of property of coal mining enterprises.

The main reason is that the expansion of coal seam fissures is not sufficient before the traditional Shimen coal mining technology, and the regional fissure network has not been realized.

Moreover, after the implementation of the traditional hydraulic fracturing Shimen coal removal technology, the existence of moisture blocks the gas flow channel, which inhibits gas desorption, diffusion and penetration, resulting in insufficient pressure relief and permeability enhancement of the coal seam before Shimen coal removal. High stress and gas pressure, high gas content, high risk

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