One well three-purpose mash gas harnessing method for ground well drilling and ground well drilling

Abstract

Mash gas treating method of floor well drilling having three functions and floor well drilling are disclosed, the character of it is that gas is token out by using the same floor well drilling in ground with the following steps; First, before exploiting , mounting fracturing well formal floor well drilling, forming artificial slit and gas producing channel with fracturing method in coal seam, collecting gas using positive-pressure released by gas burning-self, eliminating projection of lower coal and gas; Second exploiting lower coal group, pressure relief and stress releasing of upper coal group and middle coal group when lower coal group is exploited, and gas of upper coal group and middle coal group in bending subsiding belt is exploited by negative-pressure type in the same floor well drilling; Finally, when exploiting upper coal group and middle coal group, once more the same floor well drilling negative-pressure exploits the exploited region gas in middle coal group or upper coal group working surface. Gas exploiting ratio of the method is high, ratio between cost and efficiency is good, and exploited gas concentration is high.

Description

technical field [0001] The invention relates to a coal mine gas control method and drilling, more specifically a method and a drilling structure for controlling mine gas by using ground drilling to realize safe production in coal mining. Background technique [0002] The Huaibei mining area in Anhui Province is located in East China. It is an important coal production base in my country. The coal measure strata are Carboniferous and Permian, and generally contain 8 to 36 coal beds. There are mainly three coal formations in the mineable coal seam, the upper coal formation refers to the 3rd and 4th coal seam, the middle coal formation refers to the 7th, 8th and 9th coal seam, and the lower coal formation refers to the 10th coal seam, the total thickness is 7-23m, and the mineable thickness is 2.95-20.97m . Most of the mines in the mining area are mines with high gas and extremely serious coal and gas outbursts, and the gas content in coal seams reaches 10-25m 3 / t, the gas p...

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Problems solved by technology

[0003] In traditional gas drainage methods such as underground drilling through layers, the gas drainage rate is less than 30%. Especially when the mine stope extends to the deep, the gas pressure and content increase, and the lower coal formation (10 coal seam), middle coal Groups (8 and 9 coal seams) have become outburst coal seams, and traditional gas drainage methods are not enough to ensure safe production of deep coal seams

[0004] Generally, the direct cost of underground gas drainage is about 2 yuan / m 3 , and due to the limitation of underground space, generally only one main pipe for gas transportation is laid underground, and the gas of various underground extraction methods enters the same main pipe, which makes it difficult to achieve high-concentration gas, which affects the utilization of gas; During the process, it directly faces the outburst coal seam, and the current anti-drilling and blowout measures are not perfect, and the occurrence of blowhole phenomenon cannot be completely avoided, threatening the life safety of employees;

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