Wind-water conversion chambering pressure-relief permeability-increasing method for composite coal seam

Abstract

The invention discloses a wind-water conversion chambering pressure-relief permeability-increasing method for a composite coal seam, which is suitable for the composite coal seam with tectonic coal and primary coal, and the hardness coefficient f of the tectonic coal is less than 0.5. A high-pressure water pump, an air compressor and a drill rod are adopted for conducting wind-water conversion chambering pressure relief and permeability increasing on the composite coal seam, and in the wind-water conversion chambering pressure relief and permeability increasing process, whether wind power chambering encounters primary coal or not is judged by judging whether the coal unloading amount can reach a metering value set in advance according to the actual situation of each layer or not; the wind-water converter is used for converting wind reaming into high-pressure hydraulic punching. By means of the air-water conversion reaming pressure relief and permeability increasing method, the phenomena of hole blocking and drill jamming in the high-pressure hydraulic punching process are effectively reduced, and the problem that the pressure relief and permeability increasing requirements cannot be met in a primary coal body with large hardness through air reaming can be solved. The method is simple, convenient to operate and good in effect.

Description

technical field [0001] The invention relates to a method for hole reaming, pressure relief and permeability enhancement, in particular to a composite coal seam air-water conversion reaming and unloading method suitable for the composite coal seam of structural coal (f<0.5) and primary coal in the process of drilling through the seam and pre-extracting coal seam gas. pressure enhancement method. Background technique [0002] In the process of underground coal seam mining in my country, gas outburst accidents occur frequently. At present, the scale of mine mining has expanded and the depth of mining has increased, and the difficulty of coal mine gas control has also increased greatly. Highlighting with gas is a top priority. In qualified mines, protective layer mining is the preferred method for regional outburst prevention, but there are still some mines that do not have the conditions for protective layer mining. An important measure of gas emission. [0003] In some mi...

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Problems solved by technology

[0004]At present, the method of hydraulic punching to relieve pressure and increase permeability is to push out a large amount of coal around the drilling hole by pressurizing the water body, forming a large hole in the coal body. At the same time, under the action of hydraulic scouring and confining pressure, the pores and fissures of the coal body are greatly developed, thereby improving the permeability of the coal body, increasing the degree of wetness of the coal body, and effectively reducing Coal seam pressure, to achieve the purpose of preventing outbursts, but in the process of punching out, the coal-water mixture often causes hole plugging and sticking, thus prolonging the construction time

[0005]For coal seam identification firmness coefficient f<0.5, which can be twisted into powder by hand, and belongs to Class IV structural coal, hydraulic punching often causes blockage during on-site construction Considering that the coal seam is extremely soft, researchers tried to use wind power instead of water power, and the hole blocking phenomenon has been significantly improved, but there will be a little relatively hard coal or primary coal in the structural coal seam. If you continue to use If the hole is reamed by wind, the anti-reflection effect may not be obvious, which may further cause the gas drainage to fail to meet the standard and affect the production process

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