High-pressure gas injection hole-drilling pressure-releasing outburst prevention method

Abstract

The invention discloses a high-pressure gas injection hole-drilling pressure-releasing outburst prevention method which comprises the steps of: firstly, carrying out common drilling operation in a bottom plate stone drift (2) of a coal bed (1) in front of a coal mining or driving face; after a drill hole (3) enters a design depth of the coal bed, drawing back a drill, sending a jet nozzle (4) and a high-pressure drill rod (5) connected with the jet nozzle into the drill hole, and connecting a high-pressure gas-storing device (6) connected with the tail of the high-pressure drill rod (5) with a high-pressure gas compressing device (7) through a high-pressure tube; starting the high-pressure gas compressing device (7), carrying out near cylinder rotary impacting, cutting and holing on the hole wall of the drill hole in the coal bed (1) by using high-pressure impact wave as a power source through the jet nozzle (4) capable of jetting high-pressure airflow and automatically rotating to ensure that the coal body around the drill hole (3) is gradually crushed and separated from the hole wall to form pressure releasing space and subjected to the pressure balanced permeability increase through ground pressure and gas pressure action. According to the invention, the drainage efficiency of the gas in the coal bed is greatly improved and the outburst damage of the coal bed is reduced.

Description

technical field [0001] The invention relates to a method for preventing outburst by digging caverns with high-pressure gas injection, especially suitable for eliminating the risk of coal seam outburst in areas with high gas and low air permeability. Background technique [0002] Coal seams contain a large amount of coalbed methane, also known as gas, which is not only a valuable resource, but also an important part of the outburst potential of coal and gas in underground coal mining. my country is a country with abundant coal resources. With the rapid development of the coal industry and the sudden increase in scale, the amount of gas gushing out has increased, and the number of coal mine accidents caused by gas outbursts and explosions has risen rapidly. However, coalbed methane is a high-quality and clean fuel. If it is properly developed, recycled and utilized, it can not only reduce the occurrence of coal mine accidents, ensure the normal production of coal mines, but al...

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Problems solved by technology

[0003] However, coalbed methane mining and regional outburst elimination in high-gassy and low-permeability coal seams are still recognized as technical problems at home and abroad. Conventional drainage is difficult and ineffective, and technical measures for pressure relief and permeability enhancement are required.

At present, the anti-permeability measures for high-gassy and low-permeability coal seams mainly include deep hole pre-splitting blasting, hydraulic slotting, and hydraulic punching. Potential safety hazards, and there are problems such as small effective drilling range, limited anti-reflection effect, heavy drilling construction workload and low drainage efficiency in the working face, which cannot meet the needs of large-scale coalbed methane mining. Other safer and more effective methods should be adopted. The method of pressure relief and permeability enhancement can expand the effective range of drilling, enhance the gas permeability of the coal body, relieve the pressure inside the coal seam as a whole, improve the permeability of coalbed methane, and thus improve the safety and extraction efficiency of coalbed methane mining.

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