Drill hole fluid sealing method for coal mine gas extraction

Abstract

The invention discloses a drill hole fluid sealing method for coal mine gas extraction. A water injection pipe is installed in an extraction pipe and is provided with a closed branch pipe penetrating through the extraction pipe and a one-way valve, a plug is installed on the surface of the extraction pipe and located on two sides of the one-way valve respectively, the water injection pipe is provided with a pressure gauge and a main valve, and an inner cavity is filled with a sealing fluid. The extraction pipe is put in a drill hole, the valve is turned on for water injection, and when pressure rises to reach a certain pressure, the main valve is closed. The water injection pipe is connected with a lower-pressure water source, water flow slow-seeping seal is continuously conducted on the drill hole, and gas extraction concentration data is observed every day. The drill hole fluid sealing method uses a cementitious viscous fluid and water as hole sealing materials to replace traditional solids based on 'solid seals colloid, colloid seals liquid and liquid seals gas', the compactness of a hole sealing section is effectively improved, and the purpose of improving a hole sealing effect is achieved.

Description

technical field [0001] The invention relates to the field of coal mine collection, in particular to a drilling fluid sealing method for coal mine gas pumping. Background technique [0002] As the mining depth of coal mines increases, the gas problem in coal mines is also becoming more and more serious. In particular, the problem of gas control in high-gas and low-permeability coal seams has been seriously restricting the safe production of coal mines. At present, the most important means to solve the problem of gas gushing and outburst in the process of mine mining is to use gas drainage. However, in the process of gas extraction, there are also various problems such as low extraction concentration, poor effect, and short duration. One of the most important restricting factors is the sealing ability of the borehole, which directly restricts the drainage effect of the borehole. In order to improve the drainage effect of boreholes and prolong the use time of boreholes, the ...

AI Technical Summary

Problems solved by technology

Although the cement mortar has a certain strength, because the cement tends to shrink after solidification, cracks will be formed on the wall of the borehole, resulting in air leakage. crack

In addition, mines usually also use polyurethane to seal holes. However, due to the nature of polyurethane, after a period of sealing, it will be deformed under the action of ground pressure, and then lose its close contact with the coal wall, resulting in air leakage. , to disable the borehole

After summarizing, it will be found that the existing borehole seals are all solid seals, and none of them can effectively seal the pores and fissures of a certain normal scale on the borehole wall, and there are various degrees of defects, which makes it necessary to improve the principle and method of hole sealing technology