A gas drainage method for anti-permeability by static blasting in low-permeability coal seams

Abstract

The invention discloses a low-air-permeable coal bed static blasting anti-reflection gas extraction method. Multiple roof bedding drill holes are constructed along the coal bed top plate, the drill holes are filled with silent breakers which are subjected to a hydration reaction to generate radial compressive stress and tensile stress to hole walls, when the tensile stress exceeds tensile strengthof coal bed roof rock, the coal bed roof starts to generate cracks, that is to say, a gas migration and output passage is built in the coal bed roof rock, the roof bedding drill holes are subjected to repairing, hole sealing and networking extraction, and coal bed gas is extracted indirectly. Meanwhile, a group of coal bed bedding drill holes are constructed in a coal bed, and migration of the coal bed gas to the roof bedding drill holes is accelerated. After it is determined that extraction reaches the standard, progressive cover type tunneling is conducted, and finally rapid tunneling of alow-air-permeable coal bed coal rod is achieved. Accordingly, by conducting static blasting fracture on the roof bedding drill holes, the gas migration and output passage is built in the coal bed roofrock, and the extraction amount and extraction rate of the low-air-permeable coal bed gas are increased.

Description

technical field [0001] The invention belongs to the technical field of enhanced drainage and anti-reflection of coal mine gas, and in particular relates to a static blasting anti-permeability gas drainage method for low-permeability coal seams. Background technique [0002] Most of the high outburst mine coal seams in my country have the characteristics of low permeability and high adsorption. Low permeability is the bottleneck of CMM drainage. In the coal roadway excavation face of low permeability coal seam, the gas exceeds the limit, the excavation speed is slow, and the excavation cost is high. How to improve the air permeability of coal seam is a key step to achieve efficient gas drainage. [0003] Anti-reflection technologies such as loosening blasting and hydraulic strengthening are effective measures to increase the air permeability of coal seams and realize efficient gas extraction. Loosening blasting anti-reflection technology is a blasting technology that break...

AI Technical Summary

Problems solved by technology

Because water suppresses gas gushing, and hydraulic strengthening measures must rely on water to strengthen and increase the permeability of coal, and the hydraulic strengthening equipment is bulky, requiring large-scale fracturing pumping stations and special isolation equipment, the use of hydraulic strengthening and anti-permeability technology It cannot fully achieve the purpose of safe, efficient and economical gas extraction

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