Permeability-improving extraction system of coal seam in borehole

Abstract

The invention discloses a permeability-improving extraction system of a coal seam in a borehole. The system comprises a hydraulic flushing device, a pre-split blasting device, a gas extraction deviceand a safety monitoring system which are all arranged in a coal mine underground extraction roadway, a coal seam bottom plate, a coal reservoir and a coal seam top plate are arranged at the top of theextraction roadway sequentially from bottom to top, the hydraulic flushing device comprises a boring machine, a drill stem, a drill bit, a high-pressure water injection pump and a water gas separator, the pre-split blasting device comprises a detonator, a lead and a PVC tube, the gas extraction device comprises a branched extraction pipe, a main extraction pipe and gas extraction equipment, and the safety monitoring system comprises a detection module, a processing module, a collection module, an on-off input-output module and a pipeline valve arranged on the branched extraction pipe. By thesystem, safety of gas extraction control is improved, gas accidents can be prevented effectively, coal seam permeability is improved effectively, gas extraction effect is improved, extraction time isreduced effectively, and gas potential safety hazards are lowered to greatest extent.

Description

technical field [0001] The invention relates to the technical field of coal mining, in particular to an anti-reflection extraction system for coal seams in boreholes. Background technique [0002] In 2017, my country's coal output reached 3.445 billion tons, accounting for about 46.4% of the world's total output. Coal's status as my country's main energy source will not be shaken for a long time, but 95% of my country's coal mining is underground work, and more than 50% Coal mining in China is plagued by gas associated with coal reserves, and gas disasters have become a major problem restricting the safe and efficient mining of coal mines in my country. [0003] With the deepening of coal mining, the gas content, gas pressure, and ground stress of coal seams gradually increase, but the permeability of coal seams decreases significantly, especially in deep soft and protruding coal seams, where the permeability is mostly 10 -3 —10 -4 mD order of magnitude, the impact range of...

AI Technical Summary

Problems solved by technology

For coal seam groups with protective layer mining conditions, protective layer mining technology is often used to drain coal seam gas in pressure relief areas, while for a large number of single low-permeability outburst coal seams that do not have protective layer mining conditions, in accordance with the "Coal and Gas Outburst Prevention Regulations" 》, the pre-extraction of coal seam gas by underground drilling has become the main gas control measure, but it is often difficult to efficiently extract such coal seam gas due to conventional gas drainage technology, which often results in an unbalanced ratio of "pumping, mining, and excavation" in the mine, which affects mine safety production

In order to build intrinsically safe mines, mines with low gas permeability and high outburst have to invest a lot of manpower, material resources and financial resources in gas drainage. However, due to the lack of breakthroughs in drainage technology, mine development is difficult. Thoroughly lead to frequent gas overruns, serious safety hazards, frequent gas accidents, and serious threats to coal mine safety production. Therefore, how to effectively solve the problem of low-permeability coal seam drainage is of great significance to coal mine safety production

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