Directional water pressure blasting method for improving coal bed gas permeability

A technology of hydraulic blasting and air permeability, which is applied in earth-moving drilling, wellbore/well components, mining equipment, etc., can solve problems such as failure to meet actual production needs, failure to meet coal seam permeability, coal and gas outburst disasters, etc.

Active Publication Date: 2013-07-10
CHONGQING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although various conventional pressure relief and permeability enhancement measures have achieved certain effects, they are still unable to meet the actual needs of

Method used

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  • Directional water pressure blasting method for improving coal bed gas permeability

Examples

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Effect test

Embodiment 1

[0016] Example 1: The average thickness of coal seam 2 in a mine is 5m, the hardness of coal seam 2 is f=3, it is a gently inclined coal seam 2, and the overlying rock layer is hard sandstone 1, and its average thickness is 20m. , using a drilling rig to drill a hole 5 into the pre-mined coal and rock mass, the hole diameter is 75mm, and the depth of the hole 5 is 24m. Then, hydraulic slitting is performed in the coal seam, and a deep flat slit is formed around the drilled hole 5 in the coal seam after cutting. A steel casing 8 with a diameter of 36 mm is placed at the orifice, and cement mortar 6 is used to fill the gap between the steel casing 8 and the borehole 5. When the cement mortar 6 is cured for more than 48 hours and has sufficient strength, The emulsion explosive 4 is filled in the PVC pipe 7 with a diameter of 32mm, and the charge amount is 100g. A detonator 3 is set every 1 m in the emulsion explosive 4, and the PVC pipe 7 is sent to the coal seam 2, and the lead ...

Embodiment 2

[0017] Example 2: The average thickness of coal seam 2 in a mine is 9m, the hardness of coal seam 2 is f=4, it is a gently inclined coal seam 2, and the overlying rock layer is hard sandstone 1, and its average thickness is 28m. , using a drilling rig to drill a hole 5 into the pre-mined coal and rock mass, the hole diameter is 94mm, and the depth of the hole 5 is 35m. Then, hydraulic slitting is performed in the coal seam, and a deep flat slit is formed around the drilled hole 5 in the coal seam after cutting. A steel casing 8 with a diameter of 45mm is placed at the orifice, and cement mortar 6 is used to fill the gap between the steel casing 8 and the borehole 5. When the cement mortar 6 is cured for more than 48 hours and has sufficient strength, The emulsion explosive 4 is filled in the PVC pipe 7 with a diameter of 40mm, and the charge is 200g. A detonating detonator 3 is set every 1 m in the emulsion explosive 4, and the PVC pipe 7 is sent to the coal seam 2, and the le...

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Abstract

A directional water pressure blasting method for improving coal bed gas permeability includes utilizing water pressure blasting splitting to change the structure of the coal and rock mass, firstly drilling holes inside a coal bed, performing high-pressure hydraulic cutting seam, and forming a deep flat slot around the drilling holes of the coal bed after cutting; and filling explosive into the drilling holes of the coal bed, then injecting water and sealing the hole, detonating the explosive to perform water pressure blasting, and enabling the periphery of the drilling holes of the coal bed to generate directional expanding fractures under the function of detonation pressures. Performing water pressure blasting in a high-gas low gas permeability coal bed can organically combine the waterpower and the explosive force of the explosive fully and reasonably, the water pressure blasting enables the cracks generated by hydraulic cutting seam to further expand and a directional expanding cross fracture net is formed on the periphery of the drilling holes of the coal bed, so that the gas permeability of the coal bed is greatly improved, the problem that the gas of the coal bed is hard to extract due to the small number of the cracks can be effectively solved, the concentrated stress of the coal bed is transferred to the deep of the coal mass, and the capacity of gas emission is improved. The directional water pressure blasting method for improving the coal bed gas permeability is simple in process, convenient to operate, safe, reliable, and good in controllability and effects.

Description

technical field [0001] The invention relates to a hydraulic blasting method, in particular to a method for improving the permeability of coal seams by directional hydraulic blasting. Background technique [0002] The permeability of coal seams is an important indicator to measure the gas pumpability of coal seams. For gas drainage of low permeability coal seams, special measures must be taken to increase the permeability of coal seams in order to effectively extract gas. Tested methods at home and abroad include: coal seam water injection, hydraulic fracturing, high-pressure hydraulic slitting, deep hole blasting, etc. Coal seam water injection is the premise that the coal seam has a certain permeability, and penetrates into the coal body through the action of seepage and capillary force. In the free state, it is released along the route of water infiltration, but for high gas coal seams, the gas permeability is often poor, and it is difficult to improve the gas drainage ra...

Claims

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Application Information

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IPC IPC(8): E21F7/00E21B43/26E21B43/263
Inventor 夏彬伟卢义玉宋晨鹏付宏伟葛兆龙刘小川刘承伟赵彬钦
Owner CHONGQING UNIV
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