Coal seam gas extraction method based on U-shaped well and directional drilling

Abstract

The invention relates to a method for cooperatively and progressively extracting coal seam gas based on a U-shaped well and a directional drilled hole. The method comprises the following steps: constructing the U-shaped drilled well on the ground; constructing the long-distance directional drilled hole in a coal seam; arranging a sieving pipe in a coal mine underground drilled hole to enable the U-shaped drilled well to be stereoscopically crossed with the underground long-distance directional drilled hole in a space; then carrying out hole sealing on the long-distance directional drilled hole; along with the tunneling of a gate roadway, continuously constructing the long-distance directional drilled hole to enable the long-distance directional drilled hole to be stereoscopically crossed with the U-shaped drilled well, so as to realize a pattern of pre-extracting the gas and progressively extracting the coal seam gas. The method provided by the invention has the advantages of simple construction process, small working amount and capability of completely replacing underground gas extraction; the investment of a working surface gas extraction pipeline is reduced and the scale of a coal mine gas extraction pump station is reduced; a fracturing construction process is not needed and the investment of a fracturing station and fracturing liquid is reduced; pollution to the fracturing liquid is avoided and the method has extremely high technicality and economical efficiency.

Description

technical field [0001] The invention belongs to the technical field of mine safety devices, and in particular relates to a method for progressively extracting coal seam gas based on U-shaped wells and directional drilling. Background technique [0002] With the rapid development of my country's national economy, the demand for energy is also increasing day by day. However, my country is a country poor in oil, low in gas, and rich in coal, so coal has long occupied the main position of my country's primary energy consumption. At present, the depth of coal mining in my country is gradually increasing, and the degree of coal and gas dynamic disasters is showing a rising trend. my country's coal industry generally adopts the method of mining protective layer or large-scale drainage to control mine gas disasters. With the continuous development of drilling technology, many mining areas have applied ground drilling technology to coal mine gas disaster control, that is: through th...

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Problems solved by technology

[0003] Aiming at the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a method for progressively extracting coal seam gas based on U-shaped wells and directional drilling, so as to avoid a large amount of gas extraction and high cost , need fracturing construction and other issues, to achieve the effect of small construction work, high stability, large gas drainage volume and high drainage concentration

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