Underground coal mine coal seam drilling high-pressure gas fracturing and permeability increasing method and system

Abstract

The invention discloses an underground coal mine coal seam drilling high-pressure gas fracturing and permeability increasing system, and belongs to the field of coal seam gas extraction. The system comprises an underground coal mine compressed air system, and is characterized in that the underground coal mine compressed air system is connected with a gas injecting system which is connected with a liquid injecting system and a slurry injecting system, a fourth valve is connected between a compressed air pipeline and a pneumatic main pipeline of the underground coal mine compressed air system, the pneumatic main pipeline is connected with a first branch pipeline, a second branch pipeline and a third branch pipeline through a four-way pipe, a sixth valve is arranged on the first branch pipeline which is connected with a pneumatic booster pump, an eighth valve is arranged on the second branch pipeline which is connected with a pneumatic first slurry injecting pump, a seventh valve is arranged on the third branch pipeline and is connected with a pneumatic second slurry injecting pump, and a fourth valve is connected to the pneumatic main pipeline. The underground coal mine compressed air system provides an air source for high-pressure gas fracturing and permeability increasing, the air source is easy to obtain, and all components in the system are no-power components and are safe and reliable.

Description

technical field [0001] The invention belongs to the field of coal seam gas extraction, in particular to an underground coal seam drilling high-pressure gas fracturing anti-permeation method and system. Background technique [0002] At present, the pressure relief and permeability enhancement measures commonly used in high-gassy and low-permeability coal seams include deep hole loosening blasting, water jet slotting technology, hydraulic punching technology and underground coal seam hydraulic fracturing technology, but deep hole blasting, water jet slotting technology, The hydraulic punching technology has problems such as small effective drilling range, heavy workload, and complicated construction technology. [0003] Hydraulic fracturing technology has achieved a certain effect in improving the permeability of underground coal seams in coal mines. The shortcomings of this technology are mainly manifested in the fact that after high-pressure water in the coal seam enters the...

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Problems solved by technology

[0002] At present, the pressure relief and permeability enhancement measures commonly used in high-gassy and low-permeability coal seams include deep hole loosening blasting, water jet slotting technology, hydraulic punching technology and underground coal seam hydraulic fracturing technology, but deep hole blasting, water jet slotting technology, The hydraulic punching technology has problems such as small effective drilling range, heavy workload, and complicated construction technology.

[0003] Hydraulic fracturing technology has achieved a certain effect in improving the permeability of underground coal seams in coal mines. The shortcomings of this technology are mainly manifested in the fact that after high-pressure water in the coal seam enters the coal body, the viscous minerals in the coal body will expand, and the coal seam will soften, resulting in crack channels. Blockage, weakening the effect of hydraulic fracturing to enhance the permeability of coal

When the fracturing medium changes from water to gas, the above problems will be overcome. However, due to the compressibility of gas, the fracturing pressure of gas fracturing coal seams will be much higher than water pressure, and high-pressure gas fracturing coal seams will face sealing problems. , once the seal is not tight, the gas pressure of the fracturing coal seam cannot reach the fracturing pressure of the coal seam, resulting in the failure of the high-pressure gas fracturing coal seam

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