A blowout prevention device for working wellheads

Abstract

A blowout preventer for wellhead operations, belonging to the field of oil well casing operation technology. This utility model solves the problem of oil spraying out of the wellhead during forced retrieval and unsealing operations of existing oil well casing. A connecting flange is installed at the lower part of the casing, and an upper flange is installed at the upper part of the casing. The upper pressure cap is threadedly connected to the upper flange. A self-sealing core is sleeved on the tubing string, with its upper part clamped between the upper pressure cap and the upper flange. The lower part of the self-sealing core elastically fits against the outer wall of the tubing string. A valve and pressure gauge are connected and installed in the middle of the casing. This utility model is used for forced retrieval and unsealing operations of oil well casing.

Description

Technical Field

[0001] This utility model relates to a blowout prevention device for wellhead operations, belonging to the field of oil well casing operation technology. Background Technology

[0002] In oil well casing operations, when unsealing faulty bridge plugs and downhole tools inside the casing, current technology generally employs a forced retrieval unsealing method. However, because the downhole tubing string consists of multiple tubings connected sequentially by couplings, the difference in diameter between the couplings and the tubing makes it difficult to effectively seal the gap between the tubing and the casing without affecting the unsealing operation. This results in high-pressure well fluid and flammable gases flowing out of the wellhead during the unsealing operation, preventing on-site unsealing and causing serious re-contamination of the wellhead. Utility Model Content

[0003] The present invention aims to solve the above-mentioned technical problems and thereby provide a blowout prevention device for working wellheads.

[0004] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: A blowout preventer for a working wellhead includes a pipe body, a connecting flange, and a plugging assembly. The connecting flange is installed at the lower part of the pipe body. The plugging assembly includes an upper flange, a self-sealing core, and an upper pressure cap. The upper flange is installed at the upper part of the pipe body, and the upper pressure cap is threadedly connected to the upper flange. The self-sealing core is sleeved on the tubing string, with its upper part clamped between the upper pressure cap and the upper flange. The lower part of the self-sealing core elastically fits against the outer wall of the tubing string. A valve and a pressure gauge are connected and installed in the middle of the pipe body.

[0005] Furthermore, the internal through hole of the upper flange is a two-stage stepped hole, and the small diameter section of the two-stage stepped hole is threaded to the upper part of the pipe body, while the large diameter section of the two-stage stepped hole is arranged above the pipe body.

[0006] Furthermore, a smooth transition is provided between the large-diameter section and the small-diameter section of the two-stage stepped hole.

[0007] Furthermore, the internal through hole of the upper pressure cover is a three-stage stepped hole, and the small diameter section of the three-stage stepped hole is threadedly connected to the upper part of the upper flange. The upper part of the self-sealing core is sandwiched between the shoulder surface of the middle diameter section of the three-stage stepped hole and the top of the upper flange.

[0008] Furthermore, the self-sealing core includes an installation section and a sealing section. The installation section is sandwiched between the upper pressure cap and the upper flange, and the surface of the installation section that contacts the top of the upper flange is integrally formed with an annular limiting protrusion. The top of the upper flange is correspondingly provided with an annular limiting groove. Furthermore, the sealing section has a conical structure with its lower end being a small-diameter end.

[0009] Furthermore, the self-sealing core is made of rubber.

[0010] Furthermore, an oil drain pipe is connected and fixed to the middle of the pipe body, and the valve is installed at the oil outlet end of the oil drain pipe.

[0011] Furthermore, an oil connector is fixed to the end of the valve away from the oil drain pipe.

[0012] Furthermore, the inner diameter of the pipe is the same as the inner diameter of the wellhead.

[0013] Compared with the prior art, the present invention has the following advantages: This utility model's wellhead blowout preventer uses a self-sealing core to seal tubing and couplings of different diameters, thus achieving a reliable dynamic seal between the wellhead and the working tubing. The well fluid pressure inside the casing can be monitored in real time via a pressure gauge, and the well fluid can be manually discharged into a tanker truck via a valve, ensuring that wellhead operations meet the environmental requirements of controllable well fluid pressure and no spillage. On-site operation is convenient and quick, achieving a safe and reliable blowout preventer effect.

[0014] This utility model's wellhead blowout preventer is simple and quick to operate, has a small structural size, is easy to maintain, and has low manufacturing cost. Attached Figure Description Figure 1 This is a schematic front cross-sectional view of the blowout prevention device at the wellhead of this utility model; Figure 2 This is a schematic cross-sectional view of a self-sealing core.

[0015] In the diagram: 1. Pipe body; 2. Connecting flange; 3. Upper flange; 4. Self-sealing core; 41. Installation section; 42. Sealing section; 43. Annular limiting ridge; 5. Upper pressure cap; 6. Valve; 7. Pressure gauge; 8. Drain pipe; 9. Oil collar; 10. Pipe string; 11. Steel ring; 12. Wellhead flange; 13. Bolt and nut assembly; 14. Unsealing and retrieval cylinder. Detailed Implementation

[0016] Specific implementation method one: Combining Figure 1 and Figure 2 This description aims to clearly and completely describe the technical solutions in this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0017] It should be noted that the descriptions of "front," "rear," "left," "right," "inner," "outer," "left side," "right side," "upper part," "lower part," "top," and "bottom" in this utility model are defined based on the orientation or positional relationships shown in the accompanying drawings. They are merely for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the described structure must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0018] In the description of this utility model, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0019] A blowout preventer for a working wellhead includes a pipe body 1, a connecting flange 2, and a plugging assembly. The connecting flange 2 is installed at the lower part of the pipe body 1. The plugging assembly includes an upper flange 3, a self-sealing core 4, and an upper pressure cap 5. The upper flange 3 is installed at the upper part of the pipe body 1. The upper pressure cap 5 is threadedly connected to the upper flange 3. The self-sealing core 4 is sleeved on the tubing string 10, and the upper part of the self-sealing core 4 is clamped between the upper pressure cap 5 and the upper flange 3. The lower part of the self-sealing core 4 is elastically fitted to the outer wall of the tubing string 10. A valve 6 and a pressure gauge 7 are connected and installed in the middle of the pipe body 1.

[0020] When using the blowout preventer at the working wellhead of this utility model, the docking flange 2 is connected to the wellhead flange 12 and fixed by bolt and nut assembly 13, which facilitates the installation and disassembly of the entire blowout preventer at the working wellhead.

[0021] The bolt and nut assembly 13 includes a flange bolt and nuts threaded to both ends of the flange bolt.

[0022] When performing a forced unsealing operation, first install the working wellhead blowout preventer of this utility model on the wellhead flange 12, then connect the unsealing tube 14 to the lower end of the working string 10, and then pass the working string 10 with the unsealing tube 14 through the self-sealing core 4 and the pipe body 1 in sequence into the wellhead casing for unsealing operation.

[0023] This utility model's wellhead blowout preventer uses a self-sealing core 4 to seal tubing and couplings of different diameters within the tubing string 10, thereby achieving a reliable dynamic seal between the wellhead and the working tubing string 10. The pressure gauge 7 can monitor the well fluid pressure inside the casing in real time, and the valve 6 can be manually controlled to discharge the well fluid into a tanker truck as needed, ensuring that wellhead operations meet the environmental requirements of controllable well fluid pressure and no well fluid spillage. On-site operation is convenient and quick, achieving a safe and reliable blowout preventer effect.

[0024] Both the mating flange 2 and the wellhead flange 12 have annular grooves. Before installing the wellhead blowout preventer, a steel ring 11 is placed in the groove on the wellhead flange 12, and then the wellhead blowout preventer is installed. This enables the mating flange 2 and the wellhead flange 12 to be quickly connected, thereby effectively improving the installation efficiency.

[0025] The blowout preventer at the wellhead of this invention is simple and quick to operate, has a small structural size, is easy to maintain, and has low manufacturing cost.

[0026] A handle is installed on valve 6 to facilitate the opening and closing of valve 6.

[0027] The internal through-hole of the upper flange 3 is a two-stage stepped hole, and the small-diameter section of the two-stage stepped hole is threaded to the upper part of the pipe body 1, while the large-diameter section of the two-stage stepped hole is located above the pipe body 1. This design, by setting two-stage stepped holes and arranging the large-diameter section above the pipe body 1, provides more room for the self-sealing core 4 to move, thereby ensuring that the self-sealing core 4 can smoothly pass through larger diameter structures such as couplings.

[0028] The two-stage stepped bore features a smooth transition between the large and small diameter sections. This design prevents oil residue from remaining at the transition shoulder of the two-stage stepped bore.

[0029] The internal through hole of the upper pressure cap 5 is a three-stage stepped hole, and the small-diameter section of the three-stage stepped hole is threadedly connected to the upper part of the upper flange 3. The upper part of the self-sealing core 4 is clamped between the shoulder surface of the middle-diameter section of the three-stage stepped hole and the top of the upper flange 3. This design achieves stable clamping of the self-sealing core 4.

[0030] The self-sealing core 4 includes an installation section 41 and a sealing section 42. The installation section 41 is sandwiched between the upper pressure cap 5 and the upper flange 3. The surface of the installation section 41 that contacts the top of the upper flange 3 is integrally formed with an annular limiting protrusion 43, and the top of the upper flange 3 is correspondingly provided with an annular limiting groove. This design, through the cooperation of the annular limiting protrusion 43 and the annular limiting groove, further limits the self-sealing core 4, thereby effectively ensuring that the self-sealing core 4 maintains a tight connection with the upper pressure cap 5 and the upper flange 3 when moving along the tubing column 10, ensuring the overall sealing performance of the device.

[0031] The sealing section 42 has a conical structure with a small-diameter end at its lower end. This design further ensures dynamic sealing performance.

[0032] The self-sealing core 4 is made of rubber. This design allows it to better adapt to changes in the diameter of the tubing 10, further ensuring dynamic sealing performance.

[0033] An oil drain pipe 8 is fixedly connected to the middle of the pipe body 1, and the valve 6 is installed at the oil outlet end of the oil drain pipe 8. With this design, the oil drain pipe 8 is preferably arranged perpendicular to the pipe body 1. The valve 6 and the oil drain pipe 8 are connected by threads.

[0034] An oil connector 9 is fixedly connected to the end of valve 6 away from the oil drain pipe 8. With this design, valve 6 and oil connector 9 are connected by threads.

[0035] The inner diameter of pipe body 1 is the same as the inner diameter of the wellhead.

[0036] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A blowout preventer for working wellheads, characterized in that: The device includes a pipe body (1), a docking flange (2), and a sealing assembly. The docking flange (2) is installed at the lower part of the pipe body (1). The sealing assembly includes an upper flange (3), a self-sealing core (4), and an upper pressure cap (5). The upper flange (3) is installed at the upper part of the pipe body (1). The upper pressure cap (5) is threadedly connected to the upper flange (3). The self-sealing core (4) is sleeved on the pipe column (10), and the upper part of the self-sealing core (4) is clamped between the upper pressure cap (5) and the upper flange (3). The lower part of the self-sealing core (4) is elastically fitted to the outer wall of the pipe column (10). A valve (6) and a pressure gauge (7) are connected and installed in the middle of the pipe body (1).

2. The blowout preventer for a working wellhead according to claim 1, characterized in that: The internal through hole of the upper flange (3) is a two-stage stepped hole, and the small diameter section of the two-stage stepped hole is threaded to the upper part of the pipe body (1), while the large diameter section of the two-stage stepped hole is arranged above the pipe body (1).

3. The blowout preventer for a working wellhead according to claim 2, characterized in that: The two-stage stepped hole features a smooth transition between the large-diameter and small-diameter sections.

4. The blowout preventer for a working wellhead according to claim 1, characterized in that: The internal through hole of the upper pressure cover (5) is a three-stage stepped hole, and the small diameter section of the three-stage stepped hole is threadedly connected to the upper part of the upper flange (3). The upper part of the self-sealing core (4) is sandwiched between the shoulder surface of the middle diameter section of the three-stage stepped hole and the top of the upper flange (3).

5. A blowout preventer for a working wellhead according to claim 1, characterized in that: The self-sealing core (4) includes an installation section (41) and a sealing section (42). The installation section (41) is sandwiched between the upper pressure cover (5) and the upper flange (3). The surface of the installation section (41) in contact with the top of the upper flange (3) is integrally formed with an annular limiting protrusion (43). The top of the upper flange (3) is correspondingly provided with an annular limiting groove.

6. A blowout preventer for a working wellhead according to claim 5, characterized in that: The sealing section (42) has a conical structure and its lower end is a small diameter end.

7. A blowout preventer for a working wellhead according to claim 1, characterized in that: The self-sealing core (4) is made of rubber.

8. A blowout preventer for a working wellhead according to claim 1, characterized in that: The middle part of the pipe body (1) is connected to the oil drain pipe (8), and the valve (6) is installed at the oil outlet end of the oil drain pipe (8).

9. A blowout preventer for a working wellhead according to claim 8, characterized in that: An oil connector (9) is fixed to the end of the valve (6) away from the oil drain pipe (8).

10. A blowout preventer for a working wellhead according to claim 1, characterized in that: The inner diameter of the pipe body (1) is the same as the inner diameter of the wellhead.

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