Wellhead sealing device

Abstract

The utility model relates to the technical field of oil field oil-water well oil jacket annulus sealing, in particular to a wellhead sealing device. The wellhead sealing device comprises a top plate and a bottom plate, inner holes are formed in the centers of the top plate and the bottom plate, the lower side of the top plate is connected with a top plate sleeve, the upper side of the bottom plate is connected with a bottom plate sleeve, and the top plate sleeve and the bottom plate sleeve are respectively an inner sleeve and an outer sleeve and are connected in a sealed mode. A rubber core is arranged in a space formed by the top plate, the bottom plate, the top plate sleeve and the bottom plate sleeve, the rubber core can move in the space in the radial direction, and when the rubber core is coaxial with the top plate and the bottom plate, the maximum distance from the inner hole wall of the rubber core to the inner hole wall of the top plate is not smaller than the minimum distance from the outer wall of the rubber core to the inner sleeve. The wellhead sealing device can prevent the pipe column coupling from being damaged due to the fact that the pipe column coupling collides and hangs the top plate and the bottom plate.

Description

Technical Field

[0001] The utility model relates to the technical field of oil-water and oil-casing annulus sealing in oil fields, and particularly relates to a wellhead sealing device. Background Technique

[0002] At present, during downhole operations such as sand washing, drilling, milling, and casing grinding, for safety reasons, circulating flushing construction is required. When performing circulating flushing construction, it is necessary to seal the oil-casing annulus. Currently, the commonly used wellhead sealing device includes a top plate, a bottom plate, and a rubber core. A top plate sleeve is connected to the lower side of the top plate, and a bottom plate sleeve is connected to the upper side of the bottom plate. The bottom plate sleeve is an inner sleeve, and the top plate sleeve is an outer sleeve. The top plate sleeve and the bottom plate sleeve are hermetically connected. The outer diameter of the rubber core is equal to the inner diameter of the bottom plate sleeve. When the tubing is skewed, the rubber core is easily worn during the process of passing through the tubing collar, the sealing effect is poor, and the service life is short.

[0003] A Chinese invention patent application with the application publication number CN101899957A discloses a wellhead sealing device. In this device, the outer diameter of the rubber core is smaller than the inner diameter of the bottom plate sleeve, so that the rubber core can move radially in the space formed by the upper and lower plate bodies along with the pipe string, solving the problems of easy wear of the rubber core, poor sealing effect, and short service life of the above-mentioned wellhead sealing device. However, since the rubber core can move radially in the space formed by the upper and lower plate bodies along with the pipe string, during the process of pulling out and running in the pipe string, the pipe string collar may collide with the upper and lower plate bodies, resulting in damage to the pipe string collar. Content of the Utility Model

[0004] The purpose of the utility model is to provide a wellhead sealing device to solve the problem that when pulling out and running in the pipe string of the existing wellhead sealing device, the pipe string collar collides with the top plate and the bottom plate, causing damage to the pipe string collar.

[0005] To achieve the above purpose, the wellhead sealing device of the utility model adopts the following technical solutions:

[0006] The wellhead sealing device includes a top plate and a bottom plate. Circular holes are opened at the centers of the top plate and the bottom plate. A top plate sleeve is connected to the lower side of the top plate, and a bottom plate sleeve is connected to the upper side of the bottom plate. One of the top plate sleeve and the bottom plate sleeve is an inner sleeve, and the other is an outer sleeve and is hermetically connected. A rubber core is arranged in the space formed by the top plate, the bottom plate, the top plate sleeve, and the bottom plate sleeve. The rubber core can move radially in this space. When the rubber core is coaxial with the top plate and the bottom plate, the maximum distance from the inner hole wall of the rubber core to the inner hole wall of the top plate is not less than the minimum distance from the outer wall of the rubber core to the inner sleeve.

[0007] Further, the top plate sleeve and the bottom plate sleeve are connected by threads.

[0008] Further, the inner sleeve and the outer sleeve are hermetically matched through a radial sealing ring arranged between them. A smooth inner sleeve section hermetically matched with the radial sealing ring is provided at the outer end of the inner sleeve.

[0009] Further, the inner sleeve and the outer sleeve are sealingly fitted through a radial sealing ring disposed therebetween, and a smooth outer section of the outer sleeve is provided at the inner end of the outer sleeve for sealingly cooperating with the radial sealing ring.

[0010] Further, the upper part of the inner hole of the rubber core is bell-shaped.

[0011] Further, the lower part of the inner hole of the rubber core is bell-shaped.

[0012] Further, a sealing ring groove is formed on the bottom plate, and the sealing ring groove is used for installing a wellhead sealing ring for sealingly cooperating with the wellhead.

[0013] Further, a top plate guiding flaring is provided at the upper end of the inner hole on the top plate.

[0014] Further, a bottom plate guiding flaring is provided at the lower end of the inner hole on the bottom plate.

[0015] Further, the length of the outer sleeve is less than the length of the inner sleeve.

[0016] Beneficial effects: The wellhead sealing device of the present utility model is an improved invention. Specifically, the present utility model seals the tubing-casing annulus through the top plate, the bottom plate, the top plate sleeve, the bottom plate sleeve and the rubber core. When the rubber core is coaxial with the top plate and the bottom plate, the distance from the inner hole wall of the rubber core to the inner hole wall of the top plate is not less than the distance from the outer wall of the rubber core to the inner wall of the bottom plate sleeve. When the rubber core moves along with the tubing string to the inner wall of the bottom plate sleeve, the tubing string coupling does not exceed the inner through diameter of the top plate and the bottom plate. When pulling the tubing string in and out, the coupling will not collide with the top plate and the bottom plate, which can prevent the tubing string coupling from being damaged due to collision with the top plate and the bottom plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural view of the wellhead sealing device of the present utility model;

[0018] Figure 2 is a schematic structural view of the wellhead sealing device of the present utility model when the rubber core moves to one side of the inner sleeve along with the tubing string;

[0019] Figure 3 is a schematic structural view of the wellhead sealing device of the present utility model when the rubber core moves to the other side of the inner sleeve along with the tubing string.

[0020] In the figure: 1, top plate; 2, bottom plate; 3, rubber core; 4, radial sealing ring; 5, tubing string coupling; 6, tubing string; 7, smooth section; 8, sealing ring groove; 9, bell-shaped hole; 10, top plate sleeve; 11, bottom plate sleeve; 12, guiding reaming. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The features and performance of the wellhead sealing device of the present utility model will be further described in detail below in conjunction with the embodiments.

[0022] In view of the problem that in the existing wellhead sealing device, during the process of tripping the pipe string, the pipe string coupling may collide with the upper and lower shells, the utility model specifically provides a wellhead sealing device in which the coupling will not collide with the upper and lower shells during the process of tripping the pipe string, and can prevent the pipe string coupling from being damaged due to collision with the upper and lower shells.

[0023] In a basic embodiment, inner holes are opened in the centers of the top plate 1 and the bottom plate 2. A top plate sleeve 10 is connected to the lower side of the top plate, and a bottom plate sleeve 11 is connected to the upper side of the bottom plate. The bottom plate sleeve 11 is an inner sleeve, and the top plate sleeve 10 is an outer sleeve. The top plate sleeve 10 and the bottom plate sleeve 11 are connected by threads. The length of the top plate sleeve 10 is less than that of the bottom plate sleeve 11, which can reduce the length of the threads processed on the top plate sleeve and the bottom plate sleeve. The top plate sleeve 10 and the bottom plate sleeve 11 are in sealing cooperation through a radial sealing ring 4 provided therebetween. The inner end of the top plate sleeve 10 is provided with an outer sleeve smooth section in sealing cooperation with the radial sealing ring 4, and the outer end of the bottom plate sleeve 11 is provided with an inner sleeve smooth section in sealing cooperation with the radial sealing ring 4. An annular rubber core 3 is arranged in the space formed by the top plate 1, the bottom plate 2, the top plate sleeve 10 and the bottom plate sleeve 11. The annular rubber core 3 can move radially in this space. Since there is a gap between the rubber core and the inner sleeve, the rubber core can expand and contract freely when passing through the tubing coupling, reducing the wear of the rubber core; in another embodiment, the top plate sleeve 10 is an inner sleeve and the bottom plate sleeve 11 is an outer sleeve.

[0024] In a preferred embodiment, the top plate sleeve and the bottom plate sleeve can be connected by a flange.

[0025] In a preferred embodiment, as Figure 1 shown, a top plate guiding flaring is provided at the upper end of the inner hole on the top plate 1, and a bottom plate guiding flaring is provided at the lower end of the inner hole on the bottom plate. The upper and lower parts of the inner hole of the annular rubber core 3 are both flared, which can guide the coupling in and out of the wellhead sealing device.

[0026] In a preferred embodiment, as Figure 2As shown, the bottom plate sleeve 11 is an inner sleeve, and the top plate sleeve 10 is an outer sleeve. The top plate sleeve 10 and the bottom plate sleeve 11 are connected by threads. A radial sealing ring 4 is provided at the connection between the top plate sleeve 10 and the bottom plate sleeve 11, which can prevent the working fluid from leaking out due to the poor sealing of the lower end face of the annular rubber core 3. The inner diameter of the annular rubber core 3 is smaller than the outer diameter of the pipe string 6. An interference fit is formed between the pipe string 6 and the annular rubber core 3 to achieve sealing. The lower end face of the top plate is always in contact with the upper end face of the annular rubber core 3. When there is pressure in the well, the working fluid pushes up the lower end face of the annular rubber core 3, and at this time the liquid has a sealing assistance effect, thus realizing the sealing of the oil-casing annulus. During the process of tripping the pipe string, the annular rubber core 3 will swing radially in the space formed by the top plate 1, the bottom plate 2, the top plate sleeve 10 and the bottom plate sleeve 11 along with the pipe string 6. Since when the annular rubber core is coaxial with the top plate and the bottom plate, the distance from the inner hole wall of the annular rubber core to the inner hole wall of the top plate is not less than the distance from the outer wall of the annular rubber core to the inner sleeve, when the annular rubber core 3 moves to the side close to the inner wall of the bottom plate sleeve along with the pipe string 6, the pipe string collar 5 does not exceed the inner diameter of the top plate and the bottom plate. During the process of tripping the pipe string 6, the collar will not hit or hang on the top plate 1 and the bottom plate 2, and will not damage the collar.

[0027] In a preferred embodiment, as Figure 3 shown, when the annular rubber core 3 moves to the other side close to the inner wall of the bottom plate sleeve along with the pipe string 6, the pipe string collar 5 does not exceed the inner diameter of the top plate and the bottom plate. During the process of tripping the pipe string 6, the collar will not hit or hang on the top plate 1 and the bottom plate 2, and will not damage the collar.

[0028] In other embodiments, the shape of the rubber core may not be circular. The maximum distance from the inner hole wall of the rubber core to the inner hole wall of the top plate is not less than the minimum distance from the outer wall of the rubber core to the inner sleeve. When the rubber core moves to the side close to the inner wall of the inner sleeve, the pipe string collar 5 also does not exceed the inner diameter of the top plate and the bottom plate. During the process of tripping the pipe string 6, the collar will not hit or hang on the top plate 1 and the bottom plate 2, and will not damage the collar.

[0029] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. The scope of patent protection of the present invention is subject to the claims. All equivalent structural changes made by using the description and drawings of the present invention should be equally included in the protection scope of the present invention.

Claims

1. A wellhead sealing device, comprising a top plate and a bottom plate, wherein inner holes are opened in the centers of the top plate and the bottom plate, a top plate sleeve is connected to the lower side of the top plate, and a bottom plate sleeve is connected to the upper side of the bottom plate, wherein one of the top plate sleeve and the bottom plate sleeve is an inner sleeve and the other is an outer sleeve and is sealedly connected, and a rubber core is arranged in a space formed by the top plate, the bottom plate, the top plate sleeve and the bottom plate sleeve, and the rubber core can move radially in the space, wherein the device is characterized in that: When the rubber core is coaxial with the top plate and the bottom plate, the maximum distance from the inner hole wall of the rubber core to the inner hole wall of the top plate is not less than the minimum distance from the outer wall of the rubber core to the inner sleeve.

2. The wellhead sealing device according to claim 1, characterized in that: The top plate sleeve and the bottom plate sleeve are connected by threads.

3. The wellhead sealing device according to claim 2, characterized in that: The inner sleeve and the outer sleeve are sealed and matched through a radial sealing ring arranged therebetween, and the outer end of the inner sleeve is provided with an inner sleeve smooth section which is sealed and matched with the radial sealing ring.

4. The wellhead sealing device according to claim 2, characterized in that: The inner sleeve and the outer sleeve are sealed and matched through a radial sealing ring arranged therebetween, and the inner end of the outer sleeve is provided with an outer sleeve smooth section which is sealed and matched with the radial sealing ring.

5. The wellhead sealing device according to any one of claims 1 to 4, characterized in that: The upper part of the inner hole of the rubber core is trumpet-shaped.

6. The wellhead sealing device according to any one of claims 1 to 4, characterized in that: The lower part of the inner hole of the rubber core is trumpet-shaped.

7. The wellhead sealing device according to any one of claims 1 to 4, characterized in that: A sealing ring groove is formed on the bottom plate, and the sealing ring groove is used for installing a wellhead sealing ring that cooperates with the wellhead seal.

8. The wellhead sealing device according to any one of claims 1 to 4, characterized in that: A top plate guiding expansion opening is arranged at the upper end of the inner hole on the top plate.

9. The wellhead sealing device according to any one of claims 1 to 4, characterized in that: A bottom plate guiding expansion opening is arranged at the lower end of the inner hole on the bottom plate.

10. The wellhead sealing device according to any one of claims 1 to 4, characterized in that: The length of the outer sleeve is smaller than the length of the inner sleeve.

Images