Method for enhancing permeability improvement of soft coal body containing gas by joint action of shock waves and acidification

Abstract

The invention discloses a method for enhancing permeability improvement of a soft coal body containing gas by the joint action of shock waves and acidification. The method comprises the following steps that (1) a plurality of boreholes are formed in a crossheading of a working face; (2) a shock wave generating device is transported to the bottoms of the boreholes by using a drill pipe, and then openings of the boreholes are sealed, and then the boreholes are filled with water; (3) shock wave enhancement regions in the boreholes are selected, and the shock wave generating device is moved, so that the shock wave generating device is gradually started and operated in all shock wave enhancement areas from deep parts to shallow parts of the boreholes; (4) the drill pipe and the shock wave generating device are taken out, and the openings of the boreholes are opened to drain water from the boreholes; (5) after injecting an acid solution into the boreholes, the openings of the boreholes are sealed again and are subjected to sealed acidification; (6) the openings of the boreholes are opened to drain the acid solution in the boreholes; and (7) the steps (2)-(6) are repeated for the next borehole. According to the method for enhancing permeability improvement of the soft coal body containing the gas by the joint action of the shock waves and the acidification, the permeability improvement of the coal body containing the gas can be realized on the basis of reducing coal seam disturbance and protecting environment, and the gas extraction rate is improved.

Description

Technical field [0001] The invention relates to the field of gas drainage in the process of coal mining, in particular to a method for strengthening and increasing the permeability of gas-containing soft coal with the combined action of shock wave and acidification. Background technique [0002] my country's coal consumption accounts for more than 60% of primary energy consumption. For a long period of time in the future, the dominant position of coal in my country's primary energy consumption will not change. As the world's largest coal producer, my country is also facing severe coal safety production and a high mortality rate per million tons compared to developed countries. 92% of coal mining in my country is underground. The geological conditions for coal seams are complicated. Coal mining disasters are serious. As the mining depth extends to the depths at a rate of about 10-20m per year, coal mine disasters have become more and more serious, especially gas disasters. A key f...

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Problems solved by technology

[0004] At present, the main ways to improve the permeability of coal seam are hydraulic fracturing, hydraulic slotting, deep hole blasting, etc. The deep hole control pre-splitting blasting is easy to leave safety hazards for coal seam mining, and the effect of increasing permeability is different; Fracturing and hydraulic cutting are currently widely used, and hydraulic permeability enhancement measures are likely to induce a series of secondary disasters, and fracturing fluid is likely to cause water pollution

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