Gas drainage method for pressure relief by group of high-level directional drilling holes on the roof of coal mining face

Abstract

The invention discloses a pressure-relieving gas extraction method for a group of high-position directional drilling holes on the roof of a coal mining face. The principle is that before the mining of the working face, through the construction of high-level directional long drilling groups along the direction of the working face in the return air channel of the working face, the main hole sections of each high-level drilling are formed in the goaf after the mining of the working face The "O" ring is extended in the fissure zone, and the lower borehole is properly subsidence near the cutting hole of the working face, and the upward branch hole is constructed in the upper borehole. Gas in the gas-conducting fracture zone and the pressure relief and desorption zone after operation. This method can reduce the gas concentration in the upper corner of the working face and the return air flow, as well as drain the high-concentration gas in the pressure relief and desorption zone of the goaf, so as to achieve the goal of gas control on the working face and the recovery of gas resources.

Description

technical field The invention relates to a gas drainage method, which belongs to the field of underground gas control and gas drainage in coal mines, and in particular to a pressure relief gas drainage method for a group of high-level directional drilling holes on the roof of a coal mining face. Background technique The geological conditions of my country's coal fields are complex, which can easily lead to various major safety accidents. Among them, the gas associated with coal and existing in coal seams is one of the biggest disaster-causing factors that threaten the safety of my country's coal mines. At the same time, gas is a clean and efficient energy source. If these gas resources are effectively extracted, it will greatly alleviate the energy shortage in our country. Therefore, no matter from the perspective of ensuring mine safety production or resource utilization, coal mine gas should be extracted. During coal mining, due to the pressure difference between the inl...

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Problems solved by technology

The excavation of high-level pumping roadway requires a large amount of excavation, long construction period, and high cost; the pipeline of the return air buried pipe is easily crushed by the overlying rock that falls across, and the drainage effect is not good; The drilling trajectory is uncontrollable, and the drilling trajectory cannot be guaranteed to extend in the fracture zone; the construction of L-shaped wells in the ground mining area is difficult and costly, and the construction conditions are affected by the topography

In addition, the existing methods of gas drainage in the goaf of the working face can only extract the gas in the air-conducting fracture zone of the goaf, and this part of the gas is mixed with a large amount of air introduced by the ventilation of the working face, so it is difficult to realize resource utilization of the extracted gas

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