A drilling method of upward pressure and downward drainage for steeply inclined coal seam penetration and drainage

Abstract

The invention discloses an upper-fracturing lower-release permeability improvement and extraction method adopting stratum-through drilled holes for a heavy-pitch coal stratum. The stratum-through fracturing drilled hole is adopted for water injection fracturing, and stratum-through discharge and extraction drilled holes, the stratum-through fracturing drilled holes, an extraction main pipe and an extraction pump are adopted for gas extraction. By means of the method, regional permeability improvement of the heavy-pitch coal stratum can be achieved, injected high-pressure water can be discharged in time, and fracturing and permeability improvement of the upper part and pressure release and water discharge of the lower part are achieved. The method is simple, easy to implement, and capable of greatly improving the gas permeability of the coal stratum and increasing the gas extraction radius and gas extraction scalar quantity.

Description

technical field [0001] The invention relates to the technical field of gas drainage in coal seams, in particular to a method for gas drainage enhancement and gas drainage in steeply inclined coal seam through drilling holes with upward pressure and downward discharge. Background technique [0002] Most mining areas in my country have entered into deep mining, where the in-situ stress of deep coal seams increases, the air permeability of coal seams is lower, and it is more difficult to extract gas. 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. [0003] At present, the downhole hydraulic fracturing technology adopted in China mostly adopts the single-hole or directional-hole fracturing arrangement, and the drainage only needs to use the ...

AI Technical Summary

Problems solved by technology

If this part of water is not discharged, on the one hand, it will cause a large amount of coal seam water to be encountered during extended horizontal mining;

In the current published domestic literature, most of them focus on hydraulic fracturing technology, crack initiation and crack propagation, and there is no technical method combining fracturing and drainage.

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