Underground water seal type gas blowout prevention system

Abstract

The invention discloses an underground water seal type gas blowout prevention system which comprises an internally-inserted sleeve arranged at a drilling opening, and the outer end of the internally-inserted sleeve is connected with a section of blowout prevention sleeve. The top of the first section of blowout prevention sleeve is connected to a header pipe located at the top of a roadway through a first drainage sub-pipe; the bottom of the first-section blowout prevention sleeve is connected with a slag receiving box, and the lower part of the slag receiving box is communicated to a water seal container; a water seal vertical plate is arranged in the water seal container, and the bottom end of the water seal vertical plate is located below the liquid level in the water seal container. The inner cavity of the water seal container is divided into a gas discharge cavity and a slag discharge cavity by the water seal vertical plate; the gas discharge cavity is connected to a main pipe through a first drainage opening of the gas discharge cavity, and the gas discharge cavity is further connected with a gas collection bag; the water seal system is additionally arranged below the section of blowout prevention sleeve, when the gas pressure is large, a large part of gas can be buffered by the slag receiving box and the water seal container and then enters the main pipe of the drainage system, and the gas discharge pressure of the first drainage sub-pipe in an original drainage system is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine gas blowout prevention, and in particular relates to an underground water-sealed gas blowout prevention system. Background Art

[0002] In the process of coal mining, underground mining is crucial to coal mining efficiency. In order to speed up the mining progress and shorten the mining cycle, coal mines usually need to conduct underground drilling.

[0003] The gas produced by underground coal mining mixed with air will form flammable gas, which poses a great safety hazard. Through underground advance drilling, deep gas pipelines can be brought to the ground to achieve gas extraction and treatment, ensuring mining safety.

[0004] Advance drilling is an effective method to prevent gas outbursts. Underground advance drilling is achieved by drilling several holes in front of the working face to artificially create and maintain a longer pressure relief zone, avoiding stress concentration and high-pressure gas near the working face, thereby eliminating the risk of outbursts.

[0005] During the advance drilling process, an inner casing is usually installed at the borehole mouth, and then a blowout prevention casing is connected to the inner casing, and the blowout prevention casing is connected to the main pipe of the extraction system to extract underground gas through the main pipe. However, when the gas pressure is too high, the blowout prevention casing will be damaged, resulting in excessive gas in the tunnel, affecting construction safety. Summary of the invention

[0006] The purpose of the present invention is to provide a downhole water-sealed gas blowout prevention system to prevent gas leakage at the blowout prevention casing when the gas pressure is too high.

[0007] The present invention adopts the following technical scheme: an underground water-sealed gas blowout prevention system, comprising an inner insert casing arranged at the borehole mouth, the outer end of the inner insert casing being connected to a section of blowout prevention casing;

[0008] The top of a section of blowout prevention casing is connected to the main pipe located at the top of the tunnel through a first extraction sub-pipe;

[0009] A slag receiving box is connected to the bottom of a section of the blowout prevention casing, and the lower part of the slag receiving box is connected to a water seal container; wherein the area of ​​the connection port of a section of the blowout prevention casing and the first extraction sub-pipe is smaller than the area of ​​the connection port of a section of the blowout prevention casing and the slag receiving box;

[0010] A water seal plate is arranged in the water seal container, and the bottom end of the water seal plate is located below the liquid surface in the water seal container; the water seal plate divides the inner cavity of the water seal container into a gas discharge cavity and a slag discharge cavity;

[0011] The gas discharge chamber is connected to the main pipe through its first extraction port, and the gas discharge chamber is also connected to a gas collecting bag.

[0012] Furthermore, a first dust-proof nozzle is arranged in the slag receiving box, and a liquid spraying port of the first dust-proof nozzle faces a connecting port between a section of the blowout-proof sleeve and the slag receiving box.

[0013] Furthermore, a flushing pipe is arranged in the slag receiving box, and the flushing pipe is directed toward a bottom outlet of the slag receiving box.

[0014] Furthermore, the slag receiving box is connected to the water seal container through a transmission pipeline.

[0015] Furthermore, a second section of the blowout prevention casing is provided at the free end of the first section of the blowout prevention casing, and a spare slag receiving box is provided at the bottom of the second section of the blowout prevention casing.

[0016] Furthermore, the gas discharge chamber is a closed chamber, and a first extraction port and a second extraction port are respectively provided on the top of the chamber;

[0017] The first draw-off port is connected to the main pipe through the second draw-off sub-pipe;

[0018] The second extraction port is connected with an air collecting bag.

[0019] Furthermore, a second dust-proof nozzle is provided in the gas discharge chamber, and a liquid spraying port of the second dust-proof nozzle is directed toward a slag inlet of the water seal container;

[0020] A dust shielding plate is also arranged near the slag inlet in the gas discharge chamber. The dust shielding plate extends downward from the top plate of the water seal container, and a gap is provided between the lower end of the dust shielding plate and the liquid surface in the water seal container.

[0021] Furthermore, the top of the slag discharge chamber is open.

[0022] Furthermore, the water seal container is provided with an overflow port and a drain port;

[0023] The height of the overflow port is higher than the bottom end of the water seal vertical plate and lower than the bottom end of the dust isolation plate.

[0024] Furthermore, the air collecting bag is also connected to the main pipe through the third extraction sub-pipe.

[0025] The beneficial effect of the present invention is as follows: by adding a water seal system below a section of the blowout prevention casing, when the gas pressure is high, a large part of the gas can enter the main pipe of the extraction system through the buffering of the slag box and the water seal container, thereby greatly reducing the gas discharge pressure of the first extraction sub-pipe in the original extraction system and reducing the risk of leakage into the tunnel when the gas pressure is too high. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic structural diagram of an underground water-seal gas blowout prevention system according to an embodiment of the present invention;

[0027] Figure 2 It is a schematic structural diagram of a water seal container in an embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the internal structure of the water seal container in an embodiment of the present invention.

[0029] Among them: 10. Main pipe; 11. First extraction and discharge sub-pipe; 12. Second extraction and discharge sub-pipe; 13. Third extraction and discharge sub-pipe;

[0030] 21. First stage blowout prevention casing; 22. Second stage blowout prevention casing; 23. Slag receiving box; 24. First dust prevention nozzle; 25. Flushing pipe; 26. Spare slag receiving box;

[0031] 31. Second dust-proof nozzle; 32. Dust-proof plate; 33. Water seal plate; 34. Overflow port; 35. Drain port; 36. First extraction port; 37. Slag inlet; 38. Second extraction port;

[0032] 40. Transmission pipeline; 50. Air collecting bag; 60. Inner sleeve. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] The present invention discloses an underground water-sealed gas blowout prevention system, such as Figure 1 As shown, it includes an inserted casing 60 arranged at the mouth of the borehole, and the outer end of the inserted casing 60 is connected to a section of blowout prevention casing 21; the top of the section of blowout prevention casing 21 is connected to the main pipe 10 located at the top of the tunnel through the first extraction sub-pipe 21; the bottom of the section of blowout prevention casing 21 is connected to the slag receiving box 23, and the bottom of the slag receiving box 23 is connected to the water seal container; wherein, the area of ​​the connection port of the section of blowout prevention casing 21 and the first extraction sub-pipe 21 is smaller than the area of ​​the connection port of the section of blowout prevention casing 21 and the slag receiving box 23; a water seal vertical plate 33 is arranged in the water seal container, and the bottom end of the water seal vertical plate 33 is located below the liquid level in the water seal container; the water seal vertical plate 33 divides the inner cavity of the water seal container into a gas discharge chamber and a slag discharge chamber, the gas discharge chamber is connected to the main pipe through its first extraction port 36, and the gas discharge chamber is also connected to the gas collecting bag 50.

[0035] Among them, Figure 1 In the water seal container in FIG. 1 , the shaded portion at the bottom represents slag and the dotted portion represents liquid.

[0036] The present invention adds a water seal system below a section of blowout prevention casing. When the gas pressure is high, a large part of the gas can enter the main pipe of the extraction system through the buffering of the slag box and the water seal container, which greatly reduces the gas discharge pressure of the first extraction sub-pipe in the original extraction system and reduces the risk of leakage into the tunnel when the gas pressure is too high.

[0037] In the embodiment of the present invention, the inner sleeve is extended into the borehole and fixed to the borehole. When drilling, the drill rod is inserted into the borehole from the inside of the inner sleeve for operation. A section of blowout prevention sleeve 21 is fixedly connected to the inner sleeve 60 and realizes the sealing of the side of the drill rod to prevent gas from leaking directly into the tunnel.

[0038] The slag box 23 can not only lead out the excess gas, but also discharge the drill cuttings generated during the drilling construction.

[0039] A first dust-proof nozzle 24 is provided in the slag box 23, and a liquid spraying port of the first dust-proof nozzle 24 faces the connection port between a section of the blowout-proof sleeve 21 and the slag box 23. Since the gas and slag discharged from the connection port inevitably generate smoke and dust, the dust-removing liquid is sprayed to the connection port through the first dust-proof nozzle 24 to achieve dust reduction.

[0040] A flushing pipe 25 is provided in the slag receiving box 23, and the flushing pipe 25 is toward the bottom outlet of the slag receiving box 23. In addition, since the slag is solid, it is easy to be blocked at the outlet of the receiving box 23, so the flushing pipe 25 is provided here to flush the slag into the water seal container through a high-pressure water source.

[0041] In the present invention, the slag receiving box 23 is connected to the water seal container through the transmission pipe 40. Since a drilling rig needs to be installed at the borehole mouth and the volume in the cut tunnel is small, the water seal container needs to be set elsewhere, so the transmission pipe 40 is added. Preferably, the transmission pipe 40 is selected to have a metal hose, which has a self-shaping effect, is conducive to the transmission of slag, and the pipeline running direction can be designed according to the on-site working conditions.

[0042] In one embodiment, a second section of the blowout prevention casing 22 is further provided at the free end of the first section of the blowout prevention casing 21, and a spare slag receiving box 26 is provided at the bottom of the second section of the blowout prevention casing 22. Usually, only one section of the blowout prevention casing 21 is provided, but in order to increase the safety of the system, a second section of the blowout prevention casing 22 is added, and sealing rings are added between the two and at the parts that need to be sealed, so as to ensure the sealing performance.

[0043] like Figure 2 As shown, the gas discharge chamber of the water seal container is a closed chamber, and the top thereof is provided with a first extraction port 36 and a second extraction port 38; the first extraction port 36 is connected to the main pipe 10 through the second extraction sub-pipe 12; the second extraction port 38 is connected to the gas collecting bag 50. When the gas pressure is too high, the gas in the chamber can be directly extracted through the first extraction port 36 to relieve the extraction pressure of the first extraction sub-pipe 11. When the gas pressure continues to increase, the gas enters the gas collecting bag 50 under the action of pressure, and the gas collecting bag 50 buffers the gas, further reducing the gas discharge pressure.

[0044] A second dust-proof nozzle 31 is provided in the gas discharge chamber, and the liquid spraying port of the second dust-proof nozzle 31 is toward the slag inlet 37 of the water seal container; a dust-proof plate 32 is also provided in the gas discharge chamber near the slag inlet 37, and the dust-proof plate 32 extends downward from the top plate of the water seal container, and there is a gap between its lower end and the liquid surface in the water seal container.

[0045] The slag can be further dusted by the second dust-proof nozzle 31. Moreover, the dust can be confined near the slag inlet 37 by the dust-proof plate 32 to prevent the dust from entering the air collecting bag 50 or the main pipe 10. The shape of the dust-proof plate 32 can be an arc or a wave shape that wraps the slag inlet 37. It should be noted that it is necessary to ensure that there is a gap between the bottom end of the dust-proof plate 32 and the liquid surface in the water seal container, otherwise, the gas will be difficult to discharge.

[0046] In addition, the top of the slag discharge chamber of the water seal container is open, and on-site workers can take out the slag in time through the opening to avoid affecting the water seal effect.

[0047] Due to the continuous addition of water source by the first dustproof nozzle 24, the flushing pipe 25 and the second dustproof nozzle 31, the water seal container is provided with an overflow port 34 and a drain port 35, so as to control the liquid level in the water seal container and ensure normal operation. Figure 3 As shown, the height of the overflow port is higher than the bottom end of the water seal vertical plate and lower than the bottom end of the dust isolation plate 32.

[0048] Exemplarily, the gas collecting bag 50 is also connected to the main pipe 10 through the third extraction sub-pipe 13. Through the design of the third extraction sub-pipe 13, the gas in the gas collecting bag 50 can be discharged at an appropriate time. Moreover, when the gas pressure is particularly high, the third extraction sub-pipe 13 can also be directly opened to discharge the gas.

Claims

1. An underground water-seal gas blowout prevention system, characterized in that: It comprises an inner insert sleeve (60) arranged at the opening of the drill hole, wherein the outer end of the inner insert sleeve (60) is connected to a section of anti-blowout sleeve (21); The top of the blowout prevention casing (21) is connected to the main pipe (10) located at the top of the tunnel through the first extraction sub-pipe (21); The bottom of the first section of the blowout prevention casing (21) is connected to a slag receiving box (23), and the bottom of the slag receiving box (23) is connected to a water seal container; wherein the area of ​​the connection port between the first section of the blowout prevention casing (21) and the first extraction sub-pipe (21) is smaller than the area of ​​the connection port between the first section of the blowout prevention casing (21) and the slag receiving box (23); A water seal plate (33) is provided in the water seal container, and the bottom end of the water seal plate (33) is located below the liquid surface in the water seal container; the water seal plate (33) divides the inner cavity of the water seal container into a gas discharge cavity and a slag discharge cavity; The gas discharge chamber is connected to the main pipe via its first extraction port (36), and the gas discharge chamber is also connected to a gas collecting bag (50).

2. The underground water-seal gas blowout prevention system according to claim 1, characterized in that: A first dust-proof nozzle (24) is arranged in the slag receiving box (23), and a liquid spraying port of the first dust-proof nozzle (24) faces a connection port between the first section of the blowout-proof sleeve (21) and the slag receiving box (23).

3. A downhole water seal gas blowout prevention system as claimed in claim 2, characterized in that: A flushing pipe (25) is arranged in the slag receiving box (23), and the flushing pipe (25) is directed toward a bottom outlet of the slag receiving box (23).

4. A downhole water-seal gas blowout prevention system as claimed in claim 2 or 3, characterized in that: The slag receiving box (23) is connected to the water seal container through a transmission pipeline (40).

5. The underground water seal gas blowout prevention system according to claim 2, characterized in that: A second-stage blowout prevention casing (22) is also provided at the free end of the first-stage blowout prevention casing (21), and a spare slag receiving box (26) is provided at the bottom of the second-stage blowout prevention casing (22).

6. The underground water-seal gas blowout prevention system according to claim 2, characterized in that: The gas discharge chamber is a closed chamber, and a first extraction port (36) and a second extraction port (38) are respectively arranged on the top of the chamber; The first extraction port (36) is connected to the main pipe (10) through a second extraction sub-pipe (12); The second extraction port (38) is connected to an air collecting bag (50).

7. A downhole water seal gas blowout prevention system as claimed in claim 6, characterized in that: A second dust-proof nozzle (31) is arranged in the gas discharge chamber, and a liquid spraying port of the second dust-proof nozzle (31) faces toward a slag inlet (37) of the water seal container; The gas discharge chamber is also provided with a dust shielding plate (32) near the slag inlet (37). The dust shielding plate (32) extends downward from the top plate of the water seal container, and there is a gap between its lower end and the liquid surface in the water seal container.

8. The underground water-seal gas blowout prevention system according to claim 7, characterized in that: The top of the slag discharge chamber is open.

9. The underground water seal gas blowout prevention system according to claim 8, characterized in that: The water seal container is provided with an overflow port (34) and a drain port (35); The height of the overflow port is higher than the bottom end of the water seal vertical plate and lower than the bottom end of the dust isolation plate (32).

10. The underground water-seal gas blowout prevention system according to claim 6, characterized in that: The air collecting bag (50) is also connected to the main pipe (10) via a third extraction sub-pipe (13).

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