A method of piercing the bed of soft coal seam to increase permeability by punching and punching

Abstract

The invention discloses a coal mine working surface trace gas positive pressure collecting device and a collecting method thereof, relates to the technical field of coal seam gas extraction and is suitable for improving the permeability of a soft coal seam through floor roadway layer penetrating drill holes. The method comprises the steps that layer penetrating fracturing drill holes and hole sealing are constructed, high-pressure rubber hoses and high-pressure valves are arranged, coal seam fracturing is conducted, water in the drill holes is discharged through the high-pressure valves, layer penetrating pressure-relief drill holes are constructed, and coal and the water are discharged thorough the layer penetrating pressure-relief drill holes. According to the coal mine working surface trace gas positive pressure collecting device and the collecting method thereof, regional permeability improvement of the soft coal seam can be achieved, the fractured coal-water mixtures are discharged in time, and large-area pressure relief of the soft coal seam is achieved; accordingly, large-area coal seam pressure relief and permeability improvement are achieved, and the permeability of the coal seam and the gas extraction efficiency are greatly improved; and the method is simple and easy to operate, and good practical significance is achieved.

Description

technical field [0001] The invention relates to the technical field of coal seam gas drainage, in particular to a method for piercing a soft coal seam bottom plate and drilling a hole for pressure punching. Background technique [0002] Most mining areas in my country have entered deep mining, where the gas permeability of deep coal seams is lower and gas extraction is more difficult. Downhole hydraulic fracturing technology has the advantages of large fracturing range, large pressure relief range, and obvious anti-permeability effect, and has become an effective technical approach for deep low-permeable coal seams to increase permeability and regional pressure relief. However, the application effect of downhole hydraulic fracturing technology in soft coal seam is not good, because the strength of soft coal body is low (f value is less than 0.5), the borehole is easy to collapse, and the coal body after fracturing and water mixed together will reduce the Extraction efficien...

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Problems solved by technology

[0013] The technical problem to be solved by the present invention is to provide a soft coal seam floor piercing drilling pressure punching anti-permeability method, to overcome the soft coal seam in the prior art, the coal body and water after fracturing are mixed together, and the coal seam area cannot be realized. Large-scale anti-permeability and discharge of a large amount of coal and water after fracturing limit the desorption of gas. The fracturing water will also form a local high-pressure zone in the coal seam, which increases the risk of mining.

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