A method for increasing gas extraction in underground heating coal seams

Abstract

The invention provides a method for improving the downhole heating coal seam gas extraction amount. The method is particularly applicable to high-gas low-permeability inclined coal seam drilling gas extraction. A drilled hole is formed along the coal seam in an inclined mode. A slurry injection pipe, a slurry returning pipe and an extraction pipe are sequentially inserted into the drilled hole, and the hole orifice is sealed polyurethane; quick lime slurry is injected into the drilled hole through the slurry injection pipe, and slurry injection is not stopped until quick lime slurry flows out of the slurry returning pipe; when the temperature inside the drilled hole is increased to a certain degree, gas inside the coil body on the periphery of the drilled hole is greatly desorbed, at the moment, the quick lime slurry in the hole is discharged through the slurry injection pipe, and the coal seam gas starts to be extracted; when the temperature of the coil body on the periphery of the drilled hole is decreased to cause that the flow of gas inside the extraction pipe is greatly reduced, quick lime slurry is injected into the hole repeatedly, the coal body is heated, the coal seam gas is greatly desorbed, and therefore the gas extraction flow is increased. According to the method for improving the downhole heating coal seam gas extraction amount, the coal seam drilling gas extraction flow can be greatly improved, the coal seal gas extraction standard time is shortened, the slurry sources are wide, the cost is low, the technology is simple, and operation is convenient.

Description

technical field

[0001] The invention relates to a method for increasing the gas extraction volume of underground heating coal seams, and is especially suitable for drilling gas drainage in inclined coal seams with high gas and low permeability. Background technique

[0002] The gas permeability of coal seams in my country is generally low, which makes it difficult for underground coal seam gas to desorb and enter the coal seam gas drainage boreholes, resulting in low borehole drainage flow rate, which seriously affects the efficiency of coal seam gas drainage in my country. Chinese Invention Patent (Application No. 201210419162.X) discloses a method for improving gas recovery by injecting hot carbon dioxide into coal seams. The method is to inject hot carbon dioxide into coal seams through the ground. A new method of coalbed methane mining, which injects high-temperature nitrogen into the coal seam. The Chinese invention patent (application number 201310032766.3) discloses a...

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