Wellhead plugging structure

Abstract

The utility model discloses a wellhead leaking stoppage structure which comprises a sealing plug, a sealing ring is arranged on the outer wall of the sealing plug, and a sealing grease cavity is formed in the sealing plug. The end part of the sealing plug is connected with a screwed plug, the outer wall of the screwed plug is provided with a screw thread, and the screwed plug is connected with the connecting part of the wellhead through the screw thread; a blind plug is arranged at the end, away from the sealing plug, of the screwed plug. Based on the condition that the jackscrew or the positioning pin leaks, the jackscrew or the positioning pin gland is detached after well washing and killing, the sealing plug is sent into the positioning hole in a manual or hydraulic mode, primary sealing of the inner cavity of the positioning hole is achieved through the sealing ring, and sealing grease is injected into the sealing grease cavity to form secondary sealing. And the connecting part of the screwed plug and the wellhead is in three-stage sealing, so that leakage of the jackscrew or the positioning pin is blocked. According to the utility model, a movable tubular column of a well head does not need to be dismantled for operation, all jackscrews or positioning pins do not need to be dismantled, the long-term sealing effect is good, and the workover operation cost can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of offshore oil and gas exploitation, in particular to a wellhead plugging structure for plugging leakage at the location pins and set screws of oil and water wellheads. Background Technique

[0002] With the increase of the service life of the wellhead of oil and water wells, the internal sealing rings are easily affected by working conditions such as high temperature, high pressure and corrosion, and are prone to failure. Especially at the location pins and set screws of the tubing hanger, after the sealing fails, due to the long-term compression state of the set screws or location pins, they often cannot be disassembled and replaced even after the well is shut in. In the past, it was only possible to remove the wellhead and lift out the entire production string before replacement, which had a long operation cycle and high costs. Content of the Utility Model

[0003] In order to solve the above technical problems, the utility model provides a wellhead plugging structure. This structure can achieve rapid leakage plugging without removing the wellhead and moving the tubing string. At the same time, its pressure resistance ability is the same as the original wellhead pressure resistance level, meeting the requirements of safe production.

[0004] The utility model is achieved by adopting the following technical solutions.

[0005] A wellhead plugging structure includes a sealing plug. A sealing ring is provided on the outer wall of the sealing plug, and a sealing grease cavity is formed inside the sealing plug; a plug screw is connected to the end of the sealing plug. A thread is provided on the outer wall of the plug screw, and the plug screw is connected to the connection part of the wellhead through the thread; a blind plug is provided at the end of the plug screw away from the sealing plug.

[0006] Further, the sealing ring is in interference fit with the inner cavity of the wellhead set screw or location pin.

[0007] Further, a threaded hole is formed at the end of the plug screw away from the sealing plug, and the blind plug is embedded in the threaded hole.

[0008] Further, a central channel is formed inside the plug screw, and the central channel is communicated with the threaded hole.

[0009] The utility model has obtained the following beneficial effects.

[0010] (1) For the existing repair of leakage of set screws or location pins, it is necessary to remove the wellhead and move the tubing string for operation, and the whole set screw or location pin is disassembled and replaced, which has a long operation cycle and high costs. However, the utility model can realize the operation without moving the tubing string, with a short cycle and low construction costs;

[0011] (2) In the case of the set screw or location pin being stuck in the existing technology, it is necessary to cut or replace the tubing cross as a whole, while the utility model utilizes the internal space of the original gland and does not need to disassemble the set screw or location pin;

[0012] (3) In the prior art, replacing the set screws and locating pins requires additional external equipment and a complex installation process, and the entire workover team personnel for tubing operation are needed. However, for the present utility model, only 1 to 2 wellhead technicians are required to complete the operation, which simplifies the operation procedure, reduces the operation cost, and reduces the occupation of the construction team.

[0013] In summary, the present utility model does not require the removal of all set screws or locating pins, nor does it require the tubing operation of removing the wellhead, and can reduce the workover operation cost; the present utility model has a simple structure, convenient operation, and more reasonable and reliable multi-stage sealing performance, and is a new technology for plugging leaks in oil and water wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic structural diagram of the present utility model.

[0015] Wherein: 1. Blind plug; 2. Plug; 21. Threaded hole; 22. Central channel; 23. Thread; 3. Sealing grease cavity; 4. Sealing plug; 5. Sealing ring. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] Hereinafter, the technical solutions of the present utility model will be clearly and completely described through specific embodiments.

[0017] As Figure 1 shown, a wellhead leak plugging structure of the present utility model is a non-tubing plugging device after the leakage of the offshore wellhead set screw or locating pin. In case of leakage, it can be plugged online. According to the structure of the locating pin hole, the external part is a dust cover, and the internal part is a locating pin. After removing the dust cover, the plugging structure is installed into the external structure of the locating pin hole.

[0018] Specifically, the plugging structure is divided into three parts. The head part is a sealing plug 4, and a sealing ring 5 is arranged on the outer wall of the sealing plug 4. The sealing ring 5 is in interference fit with the inner cavity of the wellhead set screw or locating pin to achieve the sealing purpose. A sealing grease cavity 3 is formed inside the sealing plug 4, and sealing grease can be injected into the sealing grease cavity 3 to assist in the sealing operation. The sealing grease, as a secondary seal, can provide sealing when the primary seal fails.

[0019] The middle part of the plugging structure is a plug 2, and a thread 23 is arranged on the outer wall of the plug 2. The thread 23 is used for thread matching with the set screw or locating pin to achieve a three-stage seal; a threaded hole 21 is formed in the upper part of the plug 2 for pressure testing and injecting sealing grease, and the threaded hole 21 is communicated with the central channel 22 inside the plug 2.

[0020] The tail part of the plugging structure is a blind plug 1, and the blind plug 1 is embedded in the threaded hole 21 of the plug 2. The blind plug 1 is used for the sealing grease injection channel and the pressure testing interface.

[0021] Based on the leakage of the setscrew or positioning pin, after washing and killing the well, the setscrew or positioning pin gland is disassembled, and the sealing plug 4 is sent into the positioning hole manually or hydraulically. The first-stage seal of the inner cavity of the positioning hole is realized by relying on the sealing ring 5, and the second-stage seal is formed by injecting sealing grease into the sealing grease cavity 3. The connection part between the plug 2 and the wellhead is a threaded connection to form a third-stage seal, thereby blocking the leakage of the setscrew or positioning pin.

[0022] The construction steps of the present utility model are as follows:

[0023] 1. Release the annulus pressure of the operation well, and use the kill fluid to circulate and kill the well if necessary;

[0024] 2. After washing and killing the well, disassemble the setscrew or positioning pin gland and clean the inner cavity;

[0025] 3. Send the sealing plug 4 into the positioning hole manually or hydraulically, and rely on the sealing ring 5 to achieve the first-stage seal of the inner cavity of the positioning hole;

[0026] 4. Tighten the plug 2, and use a hand pump or other pressure test equipment to test the sealing performance;

[0027] 5. Disassemble the plug 2 and fill the sealing grease into the sealing grease cavity 3;

[0028] 6. After filling the sealing grease, tighten the plug 2 again, and use a hand pump or other pressure test equipment to test the sealing performance;

[0029] 7. Remove the pressure test joint, and use the blind plug 1 to block the pressure test hole (threaded hole 21).

[0030] The above-described embodiments are only described as the preferred embodiments of the present utility model, and do not limit the concept and scope of the present utility model. Without departing from the design concept of the present utility model, various modifications and improvements made by ordinary engineering and technical personnel in the field to the technical solution of the present utility model should fall within the protection scope of the present utility model. The technical content claimed by the present utility model has been fully recorded in the claims.

Claims

1. A wellhead plugging structure, characterized in that: It includes a sealing plug (4), on the outer wall of the sealing plug (4) there is a sealing ring (5), and a sealing grease cavity (3) is formed inside the sealing plug (4); the end of the sealing plug (4) is connected to a screw plug (2), on the outer wall of the screw plug (2) there are screw threads (23), and the screw plug (2) is connected to the connection part of the wellhead through the screw threads (23); at one end of the screw plug (2) far from the sealing plug (4) there is a blind plug (1).

2. The wellhead plugging structure according to claim 1, characterized in that: The sealing ring (5) is in interference fit with the inner cavity of the wellhead jackscrew or positioning pin.

3. The wellhead plugging structure according to claim 1, characterized in that: At one end of the screw plug (2) far from the sealing plug (4) there is formed a threaded hole (21), and the blind plug (1) is embedded in the threaded hole (21).

4. A wellhead plugging structure according to claim 1, characterized in that: A central channel (22) is formed inside the screw plug (2), and the central channel (22) is communicated with the threaded hole (21).

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