Slotting and fracturing cooperation networking permeability increasing method for low-permeability coal seam

Abstract

The invention provides a slotting and fracturing cooperation networking permeability increasing method for a low-permeability coal seam, which is applicable to regional gas control for high-gas-content low-permeability coal seams. The permeability increasing method comprises the following steps that: firstly, hole positions of slotting drill holes and fracturing drill holes are arranged alternately at a floor suction roadway in a networking arrangement mode; each slotting drill hole is subjected to high-pressure water jet flow slotting to form an annular slotted hole; and then, each fracturing drill hole is subjected to segmented fracturing, and a fracture net is formed in the coal seam. The slotting drill holes and the fracturing drill holes are in cooperative arrangement; the slotted holes formed by slotting are used for controlling the expanding direction of fracturing cracks; the number of cracks in the coal seam can be effectively increased through segmented fracturing multiple times; and good conditions are created for the drill hole gas extraction and the gas flowing in the coal seam. After the fracturing cracks are communicated with the slotted holes, a crack network is formed in the coal seam; the permeability coefficient of a coal body around the drill holes can be improved by 150 to 400 times; the single-drill-hole gas extraction effective influence range can be expanded by 2 to 4 times; the drill hole gas extraction quantity can be increased by 3 to 6 times; and the gas pre-extraction time in the high-gas outburst coal seam can be effectively shortened.

Description

technical field [0001] The invention relates to a collaborative networked anti-permeability method of slotting and fracturing in a low-permeability coal seam, which is especially suitable for drilling tunnels at the bottom of high-gas and low-permeability coal seams to cover coal roadway excavation and improve the efficiency of gas drainage in boreholes. Realize rapid outburst elimination in outburst coal seams. Background technique [0002] Gas drainage is the main measure to solve the problem of gas gushing in the process of mining high gas and low permeability coal seam and to prevent it. However, high-gassy and low-permeability coal seams have low permeability, and conventional drainage is difficult and ineffective, so technical measures for pressure relief and permeability enhancement are required. At present, water conservancy measures such as hydraulic slotting and hydraulic fracturing have been widely used in pressure relief and permeability enhancement of high-gass...

AI Technical Summary

Problems solved by technology

[0003] Technical problem: The purpose of this invention is to overcome the problems existing in the prior art, and to provide a low-permeability coal seam slotting and fracturing collaborative network anti-permeability method, through the cross-coordinated arrangement of slotted drilling and fracturing drilling , and fracturing the fracturing boreholes in stages to solve the problems of small impact range of slotted drilling and difficult control of the expansion direction of fracturing cracks, expanding the effective range of influence of a single borehole and realizing efficient gas drainage

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