CN102943687A - Pressure equalizing and hole sealing method for gas extraction drilling - Google Patents

Abstract

A pressure equalization sealing method for gas drainage boreholes, inserting a gas extraction pipe into a borehole under construction, inserting a drainage gas chamber connecting pipe and a pressure regulating gas chamber connecting pipe, sealing the borehole, sealing the hole The inner space is used as a gas extraction chamber, stop sealing the hole at a distance of 4-6m from the orifice, and then seal the hole at 2-3m after retreating to the orifice. Drainage pipe network is used for drainage, and the pressure regulating air chamber and the extraction air chamber are connected through a U-shaped pipe equipped with a position-indicating liquid outside the pipeline. With the gas extraction, the pressure of the extraction air chamber decreases, and the external Air enters the pressure-regulating air chamber to increase the pressure in the pressure-regulating air chamber, which is displayed by the position-indicating liquid on the U-shaped tube. When it is high, the pressure relief valve is opened to release the pressure. After the liquid column of the position-indicating liquid is stable, the pressure relief valve is closed. Through regular pressure relief, the gas leakage and the passage of external gas entering the borehole are blocked, which greatly increases the concentration of gas extraction, prolongs the effective period of gas extraction in the borehole, and improves the extraction rate of the borehole.

Description

A pressure equalization sealing method for gas drainage drilling

technical field

The invention relates to a pressure-equalizing hole sealing method for gas drainage boreholes, and is especially suitable for overcoming the technical problems of low gas drainage negative pressure and too low gas drainage concentration caused by the development of cracks outside the boreholes.

Background technique

In coal mine gas drainage work, the effect of gas drainage mainly depends on the sealing quality of the borehole. my country's coal mine drainage drilling and sealing materials and processes mainly include: clay-wood plug artificial hole sealing, hole sealing device sealing, cement mortar sealing and polyurethane and other foaming materials mechanical sealing, etc. However, as the extraction progresses, the coal wall fissures gradually expand, providing gas leakage and external gas entering the borehole channel, resulting in low gas extraction negative pressure and low gas extraction concentration, seriously affecting the extraction effect.

Contents of the invention

Technical problem: The object of the present invention is to overcome the deficiencies in the prior art, and provide a gas drainage borehole pressure equalization method that is simple, low in cost, good in effect, convenient in operation, and capable of preventing external gas from entering the drainage borehole. Sealing method.

Technical solution: The invented pressure equalization and sealing method for gas drainage boreholes includes drilling into the coal body and inserting the gas drainage pipe into the borehole. The specific steps are as follows:

a. When the gas extraction pipe is inserted into the borehole, insert the connecting pipe of the extraction gas chamber and the connecting pipe of the pressure regulating air chamber;

b. Seal the borehole from the inside to the outside according to the routine. The space inside the sealed hole is used as the extraction gas chamber. Stop sealing the hole at a distance of 4-6m from the orifice, and then retreat to the orifice and then seal the hole at 2-3m. The intermediate interval space is used as a pressure regulating air chamber, the mouth of the connecting pipe of the pressure regulating air chamber is located in the pressure regulating air chamber, and the mouth of the connecting pipe between the gas extraction pipe and the extraction air chamber is located in the extraction gas chamber;

c. A pressure relief pipe is connected to the exposed pipe of the connecting pipe of the pressure regulating air chamber through a tee, and a pressure relief valve is installed on the pressure relief pipe. Connected U-shaped tube, the U-shaped tube is filled with position-indicating liquid, and the U-shaped tube connected to the side of the connecting pipe of the extraction gas chamber is marked with a warning line to prevent the pressure difference from being too high;

d. Connect the gas extraction pipe to the gas extraction pipe network for extraction. With the extraction of gas, the pressure of the extraction air chamber decreases, and external air enters the pressure regulating air chamber to increase the pressure in the pressure regulating air chamber. Under the action of the two pressure differences, the air pressure enters through the connecting pipe of the pressure regulating air chamber, and pushes the position indicating liquid toward the direction of the connecting pipe of the extraction air chamber;

e. When the height of the position-indicating liquid on the side of the connecting pipe connected to the extraction gas chamber in the U-shaped pipe exceeds the warning line, open the pressure relief valve for pressure relief, and close the pressure relief valve when the liquid column of the position-indicating liquid is stable.

The pressure relief valve is manual pressure relief or automatic pressure relief controlled by a sensor; the position indicating liquid is mercury or a dense organic mixed liquid.

Beneficial effects: due to the adoption of the above-mentioned technical scheme, the present invention ensures that the external gas will not enter the extraction chamber by connecting the pressure-regulating air chamber with the extraction air chamber in equal pressure, and at the same time through the timely pressure relief of the pressure relief valve , effectively blocked gas leakage and external gas entry channels, increased the concentration of gas extraction, and greatly extended the validity period of gas extraction. The method is simple, low in cost, good in effect, convenient in operation, can prevent external gas from entering the drainage borehole, prolong the effective period of gas drainage, and has wide practicability.

Description of drawings

Fig. 1 is a schematic diagram of the implementation structure of the present invention.

In the figure: extraction gas chamber-1, coal body-2, gas extraction pipe-3, material plugging section-4, extraction gas chamber connecting pipe-5, pressure regulating chamber-6, pressure regulating chamber connected Pipe-7, tee-8, pressure relief pipe-9, pressure relief valve-10, U-shaped water column meter-11, water-12, warning line-13.

Detailed ways

An embodiment of the present invention will be further described below in conjunction with accompanying drawing:

The pressure equalization sealing method of the gas drainage borehole of the present invention is to drill the coal body 2 as usual, insert the gas drainage pipe 3 into the borehole, and insert the gas drainage pipe 3 into the borehole while the gas drainage pipe 3 is inserted into the borehole. The connecting pipe 5 of the gas production chamber and the connecting pipe 7 of the pressure regulating air chamber; according to the conventional method, seal the drilled hole from the inside to the outside, stop sealing the hole at a distance of 4-6m from the orifice, and then retreat to the orifice and carry out another 2-3m. The hole is sealed, the space in the middle is used as the pressure regulating chamber 6, and the space inside the plugged hole is used as the extraction chamber 1. The mouth of the connecting pipe 7 of the pressure regulating chamber is located in the pressure regulating chamber 6. The nozzle of the connecting pipe 5 of the gas collection chamber is located in the gas extraction chamber 1; the exposed pipe of the connecting pipe 7 of the pressure regulating chamber is connected to a pressure relief pipe 9 through a tee 8, and a pressure relief valve 10 is installed on the pressure relief pipe 9. A U-shaped pipe 11 connected to the extraction gas chamber communication pipe 5 is installed at the exposed port of the pressure regulating air chamber communication pipe 7. The U-shaped pipe 11 is filled with a position indicating liquid 12, and is connected to the extraction gas chamber communication pipe 5. The U-shaped pipe 11 on one side is marked with a warning line 13 to prevent the pressure difference from being too high; the gas drainage pipe 3 is connected to the gas drainage pipe network for drainage. When the pressure drops, the external air enters the pressure regulating air chamber 6, so that the pressure in the pressure regulating air chamber 6 increases. Push in the direction of the extraction gas chamber connecting pipe 5; when the height of the position indicating liquid 12 connected to the side of the extraction gas chamber connecting pipe 5 in the U-shaped pipe 11 exceeds the warning line 13, open the pressure relief valve 10 to release the pressure. Close the pressure relief valve 10 after the level liquid 12 liquid column stabilizes. The pressure relief valve 10 is for manual pressure relief or automatic pressure relief controlled by a sensor; the position indicating liquid is mercury or a denser organic mixed liquid.

Through regular pressure relief, the gas leakage and the passage of external gas entering the borehole are blocked, the concentration of gas extraction is increased, the validity period of borehole gas extraction is extended, and the extraction rate of boreholes is improved.

Claims (3)

1. A pressure-equalizing hole sealing method for a gas drainage borehole, comprising drilling a coal mass (2) and inserting a gas drainage pipe (3) into the borehole, characterized in that: a. While the gas drainage pipe (3) is inserted into the borehole, insert the drainage gas chamber connecting pipe (5) and the pressure regulating gas chamber connecting pipe (7); b. Seal the borehole from the inside to the outside according to the routine. The space inside the sealed hole is used as the extraction gas chamber (1). Stop sealing the hole at a distance of 4-6m from the orifice, and then retreat to the orifice for 2-3m. The hole is sealed, and the space in the middle is used as the pressure regulating chamber (6), the nozzle of the pressure regulating chamber connecting pipe (7) is located in the pressure regulating chamber (6), the gas drainage pipe (3) and the gas drainage chamber connecting pipe The nozzle of (5) is located in the extraction gas chamber (1); c. A pressure relief pipe (9) is connected to the exposed pipe of the pressure regulating air chamber connecting pipe (7) through a tee (8). The pressure relief pipe (9) is equipped with a pressure relief valve (10). The exposed port of the connecting pipe (7) is equipped with a U-shaped pipe (11) connected to the connecting pipe (5) of the extraction gas chamber. The U-shaped pipe (11) is filled with a position indicating liquid (12). The U-shaped pipe (11) on one side of the air chamber connecting pipe (5) is marked with a warning line (13) to prevent the air pressure differential from being too high; d. Connect the gas extraction pipe (3) to the gas extraction pipe network for extraction. With the extraction of gas, the pressure of the extraction air chamber (1) decreases, and the external air enters the pressure regulating air chamber (6), so that The pressure in the pressure regulating air chamber (6) rises, and under the effect of two pressure differences, the air pressure enters through the pressure regulating air chamber connecting pipe (7), and the position indicating liquid (12) is sent to the extraction gas chamber connecting pipe ( 5) direction push; e. When the position-indicating liquid (12) on the side of the U-shaped pipe (11) connected to the connecting pipe (5) of the extraction gas chamber exceeds the warning line (13), open the pressure relief valve (10) to release the pressure. Close the pressure relief valve (10) after the liquid column of the position indicating liquid (12) stabilizes. 2. The pressure equalization and sealing method for gas drainage drilling according to claim 1, characterized in that: the pressure relief valve (10) is manually pressure relief, or is controlled by a sensor to automatically release pressure. 3. The pressure equalization sealing method for gas drainage drilling according to claim 1, characterized in that: said position indicating liquid is mercury or a dense organic mixed liquid.