A coal mine surface horizontal well segmental dynamic coal digging method for diameter expansion

Abstract

A method for segmentally powered coal mining and diameter expansion of horizontal wells on the surface of coal mines, which belongs to the field of mine gas treatment and coal and coalbed methane co-exploitation, and can solve the problem of large amount of coal mining technology in coal mines, high cost, and safety problems in underground gas drainage. Hidden dangers, the present invention adopts dynamic diameter expansion in the target interval of the horizontal section of the coalbed methane horizontal well, and its technological process is to carry out casing section milling and mechanical reaming in the designed target horizontal section, and then use high-pressure atomized air or high-pressure mist Nitrogen gas is used for dynamic diameter expansion, so that the coal seam of the target section undergoes repeated stress concentration and unloading, so that the coal seam is broken into lumps or powder, and the air flow is used to carry the coal powder, coal lumps and cuttings to the ground. Through the present invention, the following effects are achieved: through the implementation of this scheme, the amount of ground coal removal can be increased as much as possible, so that the target coal seam section can be released from effective stress, the production capacity of the coalbed methane horizontal well can be improved, and the potential safety hazard of underground gas outburst can be eliminated. Staged dynamic expansion of horizontal wells.

Description

technical field [0001] The invention belongs to the technical field of mine gas treatment and coal and coalbed methane co-mining, and in particular relates to a segmented dynamic coal digging and diameter-expanding method for horizontal wells on the surface of coal mines. Background technique [0002] Broken, soft and low-permeability coal seams are widely distributed in my country. At present, the commonly used pre-pumping method in such high-gas mines is the coal mining technology in coal mines (including: "protective layer" coal mining and pressure relief technology, high-pressure hydraulic slotting in underground roadways or coal walls of working faces) technology, underground gas drainage hole pressure relief and coal digging technology), the underground coal digging technology has a better pressure relief effect, but the engineering volume is large and the cost is high, and there are certain safety hazards in underground gas drainage. Surface pre-drainage is only carrie...

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Problems solved by technology

[0003] The present invention aims at the problem that the underground coal mining technology of coal mines has a large amount of engineering, high cost, and certain potential safety hazards in underground gas drainage, and provides a method for segmental dynamic coal mining and expansion of horizontal wells on the surface of coal mines.

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