Gas extraction drilling blowout preventer

Abstract

The utility model belongs to coal mine underground gas control and safety equipment technical field, concretely relates to a kind of gas extraction drilling blowout preventer, comprising: blowout preventer sleeve, be sleeved in the surface of drill pipe and be provided with gap between drill pipe, first sealing mechanism is arranged in the inside of blowout preventer sleeve, first sealing mechanism is contacted with the surface of drill pipe, second sealing mechanism is arranged in the outside of blowout preventer sleeve, second sealing mechanism is sealed contacted with the drilling of coal body;Communicator, it is sleeved in the surface of drill pipe, left end is connected with blowout preventer sleeve, and right end is sealedly connected with drill pipe;The inner chamber of communicator is communicated with blowout preventer sleeve;Ejector, its drainage port simultaneously connects high-pressure gas source and water source, and its injection port is connected with communicator by conveying pipe;Separation mechanism, it is connected with communicator by conveying pipe.The utility model reduces coal dregs into separation system by first sealing mechanism, reduces the burden of separation mechanism;By second sealing mechanism, the purpose of avoiding gas leakage is achieved, and the safety of work is effectively guaranteed.

Description

Technical Field

[0001] This utility model belongs to the technical field of underground coal mine gas control and safety equipment, specifically relating to a blowout prevention device for gas extraction boreholes. Background Technology

[0002] Methane gas is formed from the decomposition of cellulose and organic matter by anaerobic bacteria during the early stages of coal formation from ancient plant deposits. In high-temperature, high-pressure environments, methane continues to be generated during coal formation due to physical and chemical processes. When pre-draining methane from high-methane or outburst-prone mines using directional long boreholes, the complex geological conditions at the working face and the high methane pressure inside the borehole during drilling can cause drill cuttings to be ejected through the gap between the drill rod and the borehole, commonly resulting in drill bit jacking and blowouts. During blowouts, large amounts of high-concentration methane and coal dust gush out of the borehole. As the concentration of the ejected methane increases, and the friction between the coal dust and external objects generates heat, methane explosions and other safety hazards may occur, seriously threatening safe production.

[0003] To address the blowout prevention issue in gas drainage drilling in soft coal seams, Chinese utility model patent CN112412462A discloses an integrated drilling and extraction hydraulic coal extraction device. This device includes a drill rod, drill bit, and a hydraulic coal extraction unit with a built-in spring-steel ball structure. Automatic switching between drilling and hydraulic coal extraction functions is achieved through water pressure control. However, this solution has the following drawbacks: 1. The spring-steel ball sealing mechanism is prone to jamming or wear in underground environments with high coal slag and poor water quality, leading to water pressure switching failure. 2. The device lacks a gas-water-slag separation structure, allowing drill cuttings and accumulated water to accumulate at the borehole opening, affecting gas extraction efficiency and increasing the risk of blockage. 3. It lacks real-time monitoring and control functions for parameters such as gas concentration and water pressure, making it impossible to dynamically adjust operating parameters according to working conditions. The blowout prevention process still relies on manual experience, resulting in a response lag.

[0004] Chinese utility model patent CN119163462A discloses a downhole water-sealed gas blowout preventer system, including an inner sleeve, a blowout preventer sleeve, a slag collection box, and a water seal container. It achieves gas-slag separation through a water seal plate and utilizes a gas collection bag to buffer high-pressure gas. The disadvantages of this solution are: 1. The water seal structure has high airflow resistance, which can easily lead to liquid level fluctuations and seal failure under continuous blowout conditions, and it is also ineffective at separating fine coal dust; 2. The system relies on multi-stage pipelines and external gas collection devices, resulting in a large size, complex installation, and difficulty in flexible deployment in narrow borehole working faces; 3. It lacks a real-time monitoring and automatic control mechanism, and cannot dynamically adjust the sealing and emission strategies according to changes in gas pressure, still posing a risk of response lag and manual intervention. Utility Model Content

[0005] The technical problem to be solved by this utility model is the problem of inadequate sealing in borehole gas extraction.

[0006] The technical solution adopted by this utility model to solve the aforementioned problem is: A blowout prevention device for gas drainage boreholes, comprising: A blowout preventer sleeve is fitted onto the surface of the drill rod with a gap between it and the drill rod. A first sealing mechanism is provided inside the blowout preventer sleeve, which is in contact with the surface of the drill rod. A second sealing mechanism is provided outside the blowout preventer sleeve, which is in sealed contact with the borehole of the coal body. A communicating vessel is fitted onto the surface of the drill pipe, with its left end connected to the blowout preventer sleeve and its right end sealed to the drill pipe; the inner cavity of the communicating vessel communicates with the blowout preventer sleeve. The jet injector has its inlet connected to both a high-pressure gas source and a water source, and its jet outlet is connected to a communicating vessel via a delivery pipe. The separation mechanism, connected to a communicating vessel via a delivery pipe, is used for gas-liquid-solid separation.

[0007] Compared with the prior art, the advantages of this utility model with the above structure are: This invention reduces the amount of coal slag entering the separation system through the first sealing mechanism, thereby reducing the burden on the separation mechanism; and achieves the purpose of preventing gas leakage through the second sealing mechanism, effectively ensuring work safety.

[0008] As a preferred option, a further technical solution to the above structure is: The first sealing mechanism includes a retaining ring and bristles. The retaining ring is fixed to the inner wall of the blowout preventer sleeve, and the bristles are densely arranged radially on the inner wall of the retaining ring, with the ends of the bristles attached to the surface of the drill pipe.

[0009] The beneficial effects obtained from the above features are as follows: In this example, the brush bristles are in close contact with the drill rod, effectively blocking the passage of coal slag particles and reducing the amount of coal slag entering the grading system.

[0010] The second sealing mechanism includes a rubber tube and a push ring; the push ring is threaded to the surface of the blowout preventer sleeve and can move axially in the blowout preventer sleeve; the rubber tube is fitted onto the blowout preventer sleeve and is located to the left of the push ring, and a retaining ring is fixedly installed at the left end of the blowout preventer sleeve, with the end face of the retaining ring abutting against the rubber tube.

[0011] The beneficial effect obtained from the above features is that the rubber tube in this example can deform flexibly, thereby forming a tighter bond with the borehole and achieving a better sealing effect.

[0012] The blowout preventer sleeve is also equipped with a branch pipe on its side wall, and an airbag is installed at the outer end of the branch pipe.

[0013] The beneficial effects obtained from the above features are: the airbag effectively relieves pressure on the blowout preventer sleeve, protecting the sleeve and the communicating vessel for safe use.

[0014] The gap between the blowout preventer sleeve and the drill pipe is 2cm to 3cm.

[0015] The beneficial effects obtained from the above features are: this smaller gap has a stabilizing effect on the flow and improves the stability of the airflow.

[0016] The communicating vessel is a four-way connector. Its left and right connecting ends are coaxial. The left connecting end is provided with a connecting thread for connecting with the blowout preventer sleeve. The right connecting end is provided with a cap, and the inner side of the cap is provided with a shaft seal. The upper and lower connecting ends of the communicating vessel are coaxial. The upper connecting end is used to connect to the separation mechanism, and the lower connecting end is used to connect to the jet injector.

[0017] The beneficial effects obtained from the above features are: the communicating vessel provides multi-fluid confluence and increases the efficiency of gas delivery.

[0018] The separation mechanism includes: The separation box has a feed inlet on the left side wall and an exhaust port on the top wall. A baffle plate is located to the right of the exhaust port inside the box, and a drain outlet is located on the right side wall of the box. A spiral blade is installed at the bottom of the box, with the right end of the spiral blade penetrating through the right side wall of the box, and a slag discharge port is located at this position on the right side wall. The cyclone separator has an air inlet on the side wall, a gas outlet on the top, and a dust discharge outlet at the bottom. The air inlet is connected to the exhaust outlet of the separator box through an extraction pipe, the gas outlet is connected to a storage device, and the dust discharge outlet is connected to the slag discharge outlet of the separator box. The coarse material collection bin is located below the slag discharge port.

[0019] The beneficial effects obtained from the above features are: the solution is small in size, has high separation efficiency, can move flexibly on the working face, and can be used in conjunction with drilling operations.

[0020] A door panel is installed on the outside of the slag discharge port. A sealing strip is set around the perimeter of the door panel. A spring is installed on the outside of the door panel, and the spring presses the door panel against the coarse material discharge port.

[0021] The beneficial effects obtained from the above features are: the door panel of this solution seals the separation box, preventing water from leaking out prematurely. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structural arrangement of this utility model; Figure 2 This is a structural diagram of the anti-spray sleeve of this utility model; Figure 3 This is an exploded view of the structure of the blowout preventer sleeve of this utility model; Figure 4 This is a structural diagram of the first sealing mechanism of this utility model; Figure 5 This is a structural diagram of the separation mechanism of this utility model; Figure 6 This is an internal perspective view of the separation mechanism of this utility model; Figure 7 This is a schematic diagram of the door panel structure for the slag discharge port of this utility model; Figure 8 This is a diagram of the door panel installation structure of this utility model.

[0023] In the diagram: 1. Blowout preventer sleeve; 2. Communicating vessel; 3. Drill rod; 4. Feed inlet; 5. Separator box; 6. Extraction pipe; 7. Cyclone separator; 8. Baffle plate; 9. Drain outlet; 10. Coarse material collection bin; 11. Slag discharge outlet; 12. Spiral blade; 13. Track device; 14. Jet ejector; 15. Conveying pipe; 16. Door panel; 17. Spring; 101. Retaining ring; 102. Rubber hose; 103. Push ring; 104. Branch pipe; 105. Airbag; 106. Fixing ring; 107. Brush bristles. Detailed Implementation

[0024] The present invention will be further described below with reference to embodiments, the purpose of which is only to better understand the content of the present invention. Therefore, the examples given do not limit the scope of protection of the present invention.

[0025] See Figures 1 to 8 The blowout prevention device for gas drainage boreholes provided by this utility model is specifically designed for the prevention of blowouts in underground gas drainage boreholes in coal mines. It mainly comprises four parts: a blowout prevention sleeve 1 for front-end sealing, a communicating vessel 2 for media convergence and transport, an ejector 14 for fluid pressurization, and a separation mechanism for gas-solid separation. Specifically... Blowout preventer sleeve 1 is fitted onto the surface of drill rod 3 and has a gap between it and drill rod 3. A first sealing mechanism is provided inside the blowout preventer sleeve 1, which is in contact with the surface of drill rod 3. A second sealing mechanism is provided outside the blowout preventer sleeve 1, which is in sealed contact with the borehole of coal body. The communicating vessel 2 is fitted onto the surface of the drill rod 3. Its left end is connected to the blowout preventer sleeve 1, and its right end is sealed to the drill rod 3. The inner cavity of the communicating vessel 2 communicates with the blowout preventer sleeve 1. The jet injector 14 has its inlet connected to both a high-pressure gas source and a water source, and its jet outlet is connected to the communicating vessel 2 via a delivery pipe 15. The separation mechanism, connected to the communicating vessel 2 via the delivery pipe 15, is used for gas-liquid-solid separation.

[0026] Each component is connected in series through pressure-resistant pipelines to form a fully enclosed blowout prevention system. After the drill rod 3 enters the coal seam, the gas in the coal seam is discharged from the gap between the drill rod 3 and the blowout preventer sleeve 1 under the formation pressure. The blowout preventer sleeve 1 is sealed to the borehole, so that the gas and dust generated during drilling can only be discharged through the gap between the blowout preventer sleeve 1 and the drill rod 3. The blowout preventer sleeve 1 and the connecting device form a cavity for sealing and collecting the mixture of gas, water and coal slag generated in the borehole. The first sealing mechanism is used to prevent large particles from entering the connecting device 2. The ejector 14 sprays out a high-pressure gas-water mixture. The water can adhere to the small dust particles of gas, achieving a certain dust reduction effect and reducing the dust concentration in the working area. This can prevent the dust and gas from mixing to form an explosive environment, thereby improving the safety of gas extraction and blowout prevention operations from the source. The airflow carries the gas-water mixture into the separation mechanism, which separates the solid particles, water and gas and discharges them separately.

[0027] As an alternative, the first sealing mechanism includes a retaining ring 106 and bristles 107. The retaining ring is fixed to the inner wall of the blowout preventer sleeve 1, and the bristles 107 are densely arranged radially on the inner wall of the retaining ring 106. The ends of the bristles 107 are attached to the surface of the drill rod 3. The first sealing mechanism allows gas to pass through. The gas with a certain pressure carries some dust particles and needs to be purified.

[0028] As an alternative, the second sealing mechanism includes a rubber tube 102 and a push ring 103; the push ring 103 is threadedly connected to the surface of the blowout preventer sleeve 1 and can move axially in the blowout preventer sleeve 1; the rubber tube 102 is fitted onto the blowout preventer sleeve 1 and is located to the left of the push ring 103, and a retaining ring 101 is fixedly installed at the left end of the blowout preventer sleeve 1, with the end face of the retaining ring 101 abutting against the rubber tube 102; by rotating the push ring 103, the push ring 103 squeezes the rubber tube 102, and the rubber tube 102, which has a certain thickness, expands under pressure, thereby tightening and sealing with the borehole of the coal body, preventing gas from escaping from the outside of the blowout preventer sleeve 1.

[0029] As a structural improvement to the blowout preventer sleeve 1, a branch pipe 104 is also provided on the side wall of the blowout preventer sleeve 1, and an air bladder 105 is installed at the outer end of the branch pipe 104. The air bladder 105 is a retractable structure. When the pressure of the gas ejection is high, the air bladder 105 inflates to relieve pressure and balance the pressure inside the blowout preventer sleeve 1, thus ensuring the safety of the blowout preventer sleeve 1 and the communicating vessel 2. More specifically, the gap between the blowout preventer sleeve 1 and the drill pipe 3 is 2cm to 3cm.

[0030] Select a blowout preventer sleeve 1 with a matching inner diameter based on the inner diameter of the drill rod 3. Insert the drill rod 3 into the blowout preventer sleeve 1. The fit between the inner diameter of the blowout preventer sleeve 1 and the drill rod 3 achieves a first-level sealing effect. By rotating the threaded ring, the rubber sleeve on the outer surface of the blowout preventer sleeve 1 is squeezed, so that the rubber sleeve fits tightly against the borehole wall, achieving a second-level sealing effect. The brush set inside the blowout preventer sleeve 1 not only blocks coal dust but also fits against the drill rod 3, achieving a third-level sealing effect. This enables the closed collection of the mixture of gas, water, and coal slag.

[0031] Optionally, the communicating vessel 2 is a four-way connector, with its left and right connecting ends coaxial. The left connecting end is provided with a connecting thread for connection with the blowout preventer sleeve 1, and the right connecting end is provided with a cap, the inner side of which is provided with a shaft seal. The upper and lower connecting ends of the communicating vessel 2 are coaxial, with the upper connecting end used to connect to the separation mechanism and the lower connecting end used to connect to the ejector 14. As a preferred option, the axes of the upper and lower connecting ends are at an angle of 30 to 50 degrees to the axes of the left and right connecting ends. This angle utilizes the high-pressure fluid of the ejector 14 to accelerate the gas.

[0032] As an alternative, the separation mechanism includes: The separation box 5 has a feed inlet 4 on the left side wall and an exhaust port on the top wall. A baffle 8 is provided on the right side of the exhaust port inside the box, and a drain outlet 9 is provided on the right side wall of the box to the right of the baffle 8. A spiral blade 12 is installed at the bottom of the box, and the right end of the spiral blade 12 penetrates through the right side wall of the box, and a slag discharge outlet 11 is provided at this position on the right side wall. Cyclone separator 7 has an air inlet on its side wall, a gas outlet on its top, and a dust discharge outlet at its bottom. The air inlet is connected to the exhaust outlet of the separation box 5 through an extraction pipe 6. The gas outlet is connected to a storage device. The dust discharge outlet is connected to the slag discharge outlet 11 of the separation box 5. The coarse material collection bin 10 is located below the slag discharge port 11.

[0033] The gas carrying coal slag particles and the gas-water mixture from ejector 14 converges in connector 2 and then enters separator 5 together. After all the material is injected into separator 5, it is blocked by baffle 8 to prevent direct spraying to drain outlet 9. Water and solid coal slag settle and separate in separator 5. The upper layer of clear water is discharged from drain outlet 9, while the gas carrying some dust particles that could not be captured by the water rises and undergoes solid-gas separation in cyclone separator 7. Under the action of centrifugal force, coal dust particles are thrown against the barrel wall and spiral down to slag discharge outlet 11, while the gas floats up and is discharged, achieving secondary separation.

[0034] Furthermore, a door panel 16 is installed on the outside of the slag discharge port 11. A sealing strip is provided around the door panel 16, and a spring 17 is installed on the outside of the door panel 16. The spring 17 presses the door panel 16 against the coarse material discharge port. When slag is not being discharged, the door panel 16 closes the separation box 5 to prevent the mixed material from leaking out prematurely.

[0035] Preferably, a filter screen is provided on the drain outlet 9 to improve the cleanliness of the drainage.

[0036] Reference Figure 1 Both the utility model and the drilling rig are mounted on the tracked device 13. The track has the characteristics of being anti-slip, wear-resistant, and having strong pressure-bearing capacity, which allows the device to move flexibly in the complex roadway floor environment of the coal mine, realize the rapid deployment and position adjustment of different drilling operation points, greatly improve the deployment efficiency of gas drainage drilling operations, and at the same time ensure the stable operation of the equipment in the complex roadway environment.

[0037] The processing procedure of this utility model: 1) During drilling operations, the mixture of gas, water, and coal slag is first sealed and collected inside the blowout preventer sleeve at the borehole opening; 2) The contents are conveyed to the separation mechanism via a communicating vessel and conveying pipe; 3) After entering the separation mechanism, the mixture settles by gravity in the separation box. The coal slag falls to the bottom of the box, and the upper layer is clear water. After the coal slag accumulates to a certain thickness, a water-blocking layer is formed at the bottom of the box to prevent water from leaking out of the slag outlet. The upper clear water is discharged from the drain outlet. The bottom layer of coal slag is discharged using spiral blades. 4) The gas is automatically separated from the water. Some of the dust particles in the gas are captured by the water, while the other part enters the cyclone separator together with the gas. The cyclone separator separates the dust particles from the gas, thus purifying the gas. The gas is then discharged after meeting the standards.

[0038] The above description is only a preferred embodiment of the present utility model and does not limit the scope of the present utility model. All equivalent changes made based on the content of the present utility model specification and its drawings are included within the scope of the present utility model.

Claims

1. A blowout prevention device for gas drainage boreholes, characterized in that, include: Blowout preventer sleeve (1) is fitted onto the surface of drill rod (3) and a gap is provided between it and drill rod (3). A first sealing mechanism is provided inside the blowout preventer sleeve (1), and the first sealing mechanism is in contact with the surface of drill rod (3). A second sealing mechanism is provided outside the blowout preventer sleeve (1), and the second sealing mechanism is in sealed contact with the borehole of the coal body. The communicating vessel (2) is fitted onto the surface of the drill rod (3), with its left end connected to the blowout preventer sleeve (1) and its right end sealed to the drill rod (3); the inner cavity of the communicating vessel (2) is connected to the blowout preventer sleeve (1); The jet injector (14) has its inlet connected to both a high-pressure gas source and a water source, and its jet outlet is connected to the communicating vessel (2) via a delivery pipe (15). The separation mechanism is connected to the communicating vessel (2) via the delivery pipe (15) for gas-liquid-solid separation.

2. The blowout prevention device for gas drainage boreholes according to claim 1, characterized in that, The first sealing mechanism includes a fixing ring (106) and bristles (107). The fixing ring is fixed to the inner wall of the blowout preventer sleeve (1). The bristles (107) are densely arranged radially on the inner wall of the fixing ring (106), and the ends of the bristles (107) are attached to the surface of the drill rod (3).

3. The blowout prevention device for gas drainage boreholes according to claim 1, characterized in that, The second sealing mechanism includes a rubber tube (102) and a push ring (103); the push ring (103) is threaded to the surface of the blowout preventer sleeve (1) and can move axially in the blowout preventer sleeve (1); the rubber tube (102) is fitted on the blowout preventer sleeve (1) and located to the left of the push ring (103); a retaining ring (101) is fixedly installed on the left end of the blowout preventer sleeve (1), and the end face of the retaining ring (101) abuts against the rubber tube (102).

4. The blowout prevention device for gas drainage boreholes according to claim 1, characterized in that, The side wall of the blowout sleeve (1) is also provided with a branch pipe (104), and an airbag (105) is installed at the outer end of the branch pipe (104).

5. The blowout prevention device for gas drainage boreholes according to claim 1, characterized in that, The gap between the blowout preventer sleeve (1) and the drill rod (3) is 2cm to 3cm.

6. The blowout prevention device for gas drainage boreholes according to claim 1, characterized in that, The communicating vessel (2) is a four-way connector. Its left connecting end and right connecting end are coaxial. The left connecting end is provided with a connecting thread for connecting with the blowout sleeve (1). The right connecting end is provided with a cap, and the inner side of the cap is provided with a shaft seal. The upper connecting end and lower connecting end of the communicating vessel (2) are coaxial. The upper connecting end is used to connect the separation mechanism, and the lower connecting end is used to connect the jet injector (14).

7. The blowout prevention device for gas drainage boreholes according to claim 6, characterized in that, The axes of the upper and lower connecting ends form an angle of 30 to 50 degrees with the axes of the left and right connecting ends.

8. The blowout prevention device for gas drainage boreholes according to claim 1, characterized in that, The separation mechanism includes: The separation box (5) has a feed inlet (4) on the left side wall and an exhaust port on the top wall. A baffle (8) is provided on the right side of the exhaust port inside the box, and a drain outlet (9) is provided on the right side wall of the box to the baffle (8). A spiral blade (12) is installed at the bottom of the box. The right end of the spiral blade (12) penetrates the right side wall of the box, and a slag discharge outlet (11) is provided at this position on the right side wall. Cyclone separator (7) has an air inlet on its side wall, a gas outlet on its top, and a dust discharge outlet at its bottom. The air inlet is connected to the exhaust outlet of the separator (5) through an extraction pipe (6), the gas outlet is connected to a storage device, and the dust discharge outlet is connected to the slag discharge outlet (11) of the separator (5). The coarse material collection bin (10) is located below the slag discharge port (11).

9. The blowout prevention device for gas drainage boreholes according to claim 1, characterized in that, A door panel (16) is installed on the outside of the slag discharge port (11). A sealing strip is provided around the door panel (16). A spring (17) is installed on the outside of the door panel (16). The spring (17) presses the door panel (16) against the coarse material discharge port.

10. The blowout prevention device for gas drainage boreholes according to claim 1, characterized in that, A filter screen is installed on the drain outlet (9).

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