Coal seam gas drainage method based on directional drilling and liquid nitrogen quick freezing and thermal fracturing

Abstract

The invention relates to a coal seam gas extraction method based on directional drilling and liquid nitrogen quick freezing and thermal cracking, belonging to the technical field of gas control. In this method, inclined boreholes are arranged along the trough on the recovery working face, and then the inclined boreholes are incorporated into the drainage pipe network for gas drainage; At the same time, long-distance directional drilling is constructed along the direction of the coal seam in the withdrawal channel or return air roadway of the mining face as the injection hole for liquid nitrogen, and then the liquid nitrogen is injected into the long-distance directional drilling. Determine whether the borehole is a borehole affected by liquid nitrogen by detecting the temperature in the borehole that indicates that the drainage fails. If it is a borehole affected by liquid nitrogen, inject high-temperature air into the borehole to make the coal around the borehole Crack occurs under the condition of rapid freezing and heat, which improves the permeability characteristics of coal body. The invention improves the gas extraction volume, has simple process and low operation cost.

Description

technical field [0001] The invention belongs to the technical field of gas control, and relates to a coal seam gas extraction method based on directional drilling and liquid nitrogen quick-freezing and thermal cracking. Background technique [0002] The coal industry provides an important support for economic and social development. Although the new energy industry is in the ascendant, its current market share is relatively small, which has not shaken the main advantage of the coal industry. Coal mine gas (also known as "coalbed methane") is a kind of unconventional natural gas associated with coal and mainly stored in coal seams in the state of adsorption. Its main component is methane, with a small amount of ethane, propane and butane, generally Contains hydrogen sulfide, carbon dioxide, nitrogen and moisture, and traces of inert gases such as helium and argon. Gas is the main factor that threatens the safe production of mines, but it is also a kind of clean energy. As ...

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Problems solved by technology

[0004] In view of this, the object of the present invention is to provide a method of coal seam gas extraction based on directional drilling and liquid nitrogen quick freezing and thermal fracturing to solve the problem of high gas or coal and gas outburst gas in the mining face The problem of rapid decay of extraction volume

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