Coal bed hydraulic cutting and sieve tube feeding linked gas extraction apparatus and method

Abstract

The invention relates to a coal bed hydraulic cutting and sieve tube feeding linked gas extraction apparatus and method, which belongs to the technical field of coal mine safety. The apparatus comprises a drill rod, a high-pressure water flow outer pipe, a special drill bit, a drill rod connecting apparatus, a drill rod tail switching apparatus, a high-pressure water pipe, a flexible sieve tube and a fixing apparatus; the special drill bit is connected with the drill rod, the drill rod is connected with a drilling machine, and the drilling machine is started to drill to a preset depth; the drill rod 10 is a double-layer structure, the inner pipe of the drill rod and an annular space of the drill rod form the high-pressure water flow outer pipe, and the inner pipe and the drill rod are of an embedded structure; the inner pipe of the drill rod is connected with the drill rod connecting apparatus, and the drill rod tail switching apparatus is connected with the flexible sieve tube or thehigh-pressure water pipe; and the flexible sieve tube is connected with the fixing apparatus, so that no movement occurs in the process of withdrawing the drilling and cutting coal. By adopting the coal bed hydraulic cutting and sieve tube feeding linked gas extraction apparatus, a gas flow passage is effectively prevented from being blocked due to the collapse of a borehole; and meanwhile, the secondary hydraulic cutting for the coal body can increase an exposed area of the coal body and improve the gas extraction effect.

Description

technical field [0001] The invention belongs to the technical field of coal mine safety, and relates to a coal mine underground coal seam hydraulic slotting and a lower screen pipe linkage gas extraction device and method. Background technique [0002] Coalbed methane, also known as "coal mine gas", is a hydrocarbon gas that exists in coal seams and coal-measure strata. The main component is methane, and it is an associated mineral resource of coal. When its concentration in the air reaches 5%-16%, it will explode in case of an open flame, which was once one of the main threats to coal mine safety production. On the other hand, coalbed methane is a good fuel for industry, chemical industry, power generation and residential life. 1 cubic meter of CBM is approximately equivalent to 9.5 kilowatt-hours of electricity, 1.13 kilograms of gasoline, and 1.21 kilograms of standard coal. The calorific value of coalbed methane is 2 to 5 times that of common coal, and it hardly produc...

AI Technical Summary

Problems solved by technology

However, because most of the high gas or coal and gas outburst mine coal seams in China are low permeability and soft coal seams, the air permeability is poor, and the drilling holes constructed in the coal seam are prone to collapse, resulting in poor drainage effect

At present, although there are measures such as underground hydraulic fracturing or high-pressure hydraulic slotting to improve the air permeability of the coal seam and increase the amount of gas extracted from the borehole, as the drainage operation proceeds, the gas drainage borehole is prone to collapse , thus blocking the flow channel of gas in the borehole and reducing the effect of gas drainage

Images