A Cooling and Heating Alternating System for Improving Coal Seam Gas Drainage

Abstract

The invention relates to a cooling and heating alternating system for improving coal-bed gas extraction amount. The cooling and heating alternating system for improving the coal-bed gas extraction amount relates to a production increase system for expanding coal body fractures and improving gas extraction amount. According to the cooling and heating alternating system for improving the coal-bed gas extraction amount, a flow injection pie and a gas extraction pipe I which are fed into a surface borehole enter into a ground surface through a sealing device; the outer end of the gas extraction pipe I is respectively connected with a drainage pipe and a gas extraction pipe II through a first tee joint; the other end of the gas extraction pipe II is connected with an extraction pump; a valve I is arranged between the first tee joint and the drainage pipe; a valve II and a flowmeter III are arranged on the gas extraction pipe II; the ground surface end of the flow injection pipe is divided into a gas injection pipe I and an extending end through a second tee joint; the extending end of the flow injection pipe is respectively connected with a gas injection pipe II and a water injection pipe through a third tee joint. With the application of the cooling and heating alternating system, the fractures under a colliery is reasonably expanded, so that the gas can be extracted maximally, and the cooling and heating alternating system is suitable for use in coal bed areas with low hole fracture development degree and relatively low permeability.

Description

technical field [0001] The invention relates to a cooling and heating alternating system for increasing coal seam gas extraction volume, and relates to a production increasing system for expanding coal body fissures and increasing gas extraction volume. Background technique [0002] The low permeability of coal seams in my country is the main reason for limiting the effect of pre-extraction gas from ground drilling. In order to improve the permeability of coal seams, hydraulic fracturing technology is generally used for coal seam anti-permeability treatment. However, the cracks produced by hydraulic fracturing mainly expand along the direction perpendicular to the minimum principal stress, and the number of cracks produced is small, and it is difficult to form longer cracks. It has a volume fracture effect on coal seam storage. At present, the application effect of this technology in most mining areas in my country is not ideal, and it is urgent to develop a new method and ...

AI Technical Summary

Problems solved by technology

In order to improve the permeability of coal seams, hydraulic fracturing technology is generally used for coal seam anti-permeability treatment. However, the cracks produced by hydraulic fracturing mainly expand along the direction perpendicular to the minimum principal stress, and the number of cracks produced is small, and it is difficult to form longer cracks. Produce volume fracture effect on coal seam storage

At present, the application effect of this technology in most mining areas in my country is not ideal, and it is urgent to develop a new method and system for increasing gas production in surface drilling, so as to enrich my country's technical system for efficient extraction of coal seam gas by surface drilling

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