Coal bed hydraulic fracturing and water pressure blasting coupling permeability increase method and device

Abstract

The invention belongs to the technical field of coal bed permeability increase, and particularly relates to a coal bed hydraulic fracturing and water pressure blasting coupling permeability increase method and device. Firstly, high-pressure fracturing water is injected in a coal hole to conduct first-time fracturing so that the coal bed can generate wide and deep fractures; then, second-time fracturing is conducted through a blasting device, multiple times of disturbance are achieved for the coal bed by adopting multi-stage blasting interval staged millisecond blasting, the completion degree of the coal bed is weakened multiple times, the fractures of the coal bed can be more fine and uniform, and the loose degree of the coal bed is increased; and finally, third-time fracturing is conducted through the high-pressure fracturing water, the fine fractures generated by blasting can further become wide and deep, the coal bed fractures can be large in density, large in depth and large in fracture width due to the adoption of the water pressure blasting coupling effect, the coal bed permeability increase effect is greatly enhanced, and the discharge efficiency of gas and other gas in thecoal bed is enhanced. By means of the coal bed hydraulic fracturing and water pressure blasting coupling permeability increase method and device, the long time period of the chemical agent effect in the prior art is avoided, and the coal bed exploitation efficiency is greatly improved.

Description

technical field

[0001] The invention belongs to the technical field of coal seam anti-permeability, and in particular relates to a coal seam hydraulic fracturing and hydraulic blasting coupling anti-permeability method and device. Background technique

[0002] In the process of coal mining, the coal seam has poor permeability and contains gas, so the coal seam must be mined after gas drainage. The commonly used gas drainage methods include drilling, hydraulic fracturing, blasting anti-permeability, carbon dioxide phase change fracturing, Hydraulic slits and other methods are used to increase the air permeability of the coal seam, thereby facilitating the extraction of gas, thereby improving the safety of coal seam mining.

[0003] In the prior art, the method of hydraulic fracturing is generally used for coal seam fracturing and permeability enhancement. The specific method is to drill a coal hole in the coal seam to be mined, seal the coal hole and pass high-pressure water ...

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