Sealing device for wellheads

Abstract

The application provides a sealing device of a wellhead, and relates to the technical field of oil and gas drilling and production equipment. The sealing device of the wellhead comprises a casing hanger, a sealing assembly, a first locking piece and a second locking piece. The casing hanger is installed on the wellhead. The sealing assembly is arranged in an annulus and comprises a connecting part and a sealing part. The sealing part is connected to the bottom end of the connecting part and abuts against the top end of the casing hanger. The first locking piece and the second locking piece are located on the sealing assembly. When the sealing assembly is installed downward along the axial direction of the casing hanger to the annulus, the connecting part moves downward along the axial direction of the casing hanger, drives the second locking piece to generate radial movement to lock into the second locking part of the wellhead, and drives the first locking piece to generate radial movement to lock into the first locking part of the casing hanger. The sealing device of the wellhead provided by the application can realize reliable mechanical locking between the wellhead and the casing hanger, and can improve the long-term sealing stability and structural reliability under complex working conditions while ensuring the installation convenience and operation efficiency.

Description

Technical Field

[0001] This application relates to the field of oil and gas drilling and production equipment technology, and in particular to a wellhead sealing device. Background Technology

[0002] In offshore oil drilling and production operations, the annular space between the wellhead and the casing hanger must be reliably sealed to prevent high-pressure oil and gas leakage, maintain the integrity of the wellbore pressure, and ensure operational safety.

[0003] In existing technologies, split-type metal sealing assemblies are commonly used, which typically consist of a sleeve hanger, pressure ring, locking ring, and auxiliary sealing components.

[0004] However, in existing technical solutions, the sealing surface is prone to failure under thermal cycling and cannot adapt to the displacement caused by the thermal expansion of the sleeve, thus failing to meet reliable sealing requirements under complex working conditions. Utility Model Content

[0005] In view of the above problems, this application provides a wellhead sealing device that can achieve reliable mechanical locking between the wellhead and the casing hanger, while ensuring ease of installation and operational efficiency, and improving long-term sealing stability and structural reliability under complex working conditions.

[0006] To achieve the above objectives, the embodiments of this application provide the following technical solutions:

[0007] This application provides a wellhead sealing device, including a casing hanger configured to be installed at the wellhead such that an annulus is formed between the outer wall of the casing hanger and the inner wall of the wellhead, and the outer wall of the casing hanger is configured to form a first locking portion; a sealing assembly disposed within the annulus, the sealing assembly including a connecting portion and a sealing portion connected to each other; the sealing portion is connected to the bottom end of the connecting portion and abuts against the top end of the casing hanger; the outer wall of the sealing portion is used to form a sealing structure with the inner wall of the wellhead, and the inner wall of the sealing portion is used to form a sealing structure with the outer wall of the casing hanger; a first locking member and a second locking member, the first locking member and the second locking member being located on the sealing assembly; when the sealing assembly is installed downward along the axial direction of the casing hanger into the annulus, at least a portion of the connecting portion is configured to move downward along the axial direction of the casing hanger, causing the second locking member to generate radial movement to lock into the second locking portion of the wellhead, and causing the first locking member to generate radial movement to lock into the first locking portion.

[0008] In one possible implementation, the connecting portion includes a movable portion and a supporting portion connected together; the supporting portion is connected to a sealing portion; the movable portion is configured to move axially relative to the supporting portion to drive the first locking member and the second locking member to move radially.

[0009] In one possible implementation, the movable part includes a first movable segment and a second movable segment, at least a portion of the first movable segment being detachably connected to the inner wall of the second movable segment; a support portion is connected to the inner wall of the second movable segment and is located at one end of the second movable segment near the sleeve hanger; a gap exists between the support portion and the first movable segment along the axial direction of the sleeve hanger, and both the first and second movable segments are configured to move axially relative to the support portion until the bottom end of the first movable segment abuts against the top end of the support portion; a second locking member abuts against the outer wall of the second movable segment and abuts against the top end of the sealing portion; a first locking member is located on the inner wall of the sealing portion and is located at the bottom end of the second movable segment.

[0010] In one possible implementation, the outer wall of the second moving segment is configured to form a locking groove, and at least a portion of the second locking member is located within the locking groove.

[0011] In one possible implementation, the end of the locking groove opposite to the sleeve hanger is an inclined surface.

[0012] In one possible implementation, the second moving segment and the support are connected by a shear pin; when the first moving segment is subjected to an axially downward force, the shear pin is sheared, causing the second moving segment to move axially downward relative to the support and drive the second locking member to generate radial movement to lock into the second locking part; at the same time, the bottom end of the second moving segment abuts against and pushes the first locking member, and drives the first locking member to generate radial movement to lock into the first locking part.

[0013] In one possible implementation, the sealing portion includes a first sealing section abutting against the top end of the sleeve hanger; at least a portion of the cylindrical wall of the first sealing section is configured to form a through portion extending axially along the sleeve hanger, such that a second moving section passes through the through portion axially along the sleeve hanger and abuts against a first locking member.

[0014] In one possible implementation, the sealing portion further includes a second sealing section connected to the outer wall of the through portion; a second locking member is located at the top of the second sealing section, and a first locking member is located on the inner wall of the second sealing section.

[0015] In one possible implementation, the second sealing section includes a first part and a second part connected to each other. The first part is connected to the outer wall of the through part. A first locking member is located at the top of the first part. The second part is located at the bottom of the first sealing section. Along the axial direction of the wellhead, there is a gap between the second part and the first sealing section. The inner diameter of the second part is smaller than the inner diameter of the first part. The connection between the second part and the first part is configured to form a bearing surface. The first locking member is located on the bearing surface.

[0016] In one possible implementation, the second sealing section further includes a third part connected to the bottom end of the second part; the third part is sleeved between the wellhead and the casing hanger, and multiple sealing elements are respectively provided between the third part and the casing hanger and between the third part and the wellhead.

[0017] The wellhead sealing device provided in this application includes a casing hanger, a sealing assembly, a first locking element, and a second locking element. The casing hanger is configured to be installed at the wellhead such that an annulus is formed between the outer wall of the casing hanger and the inner wall of the wellhead. The outer wall of the casing hanger is configured to form a first locking portion for engaging with the first locking element. The sealing assembly is disposed within the annulus and includes a connecting portion and a sealing portion connected to each other. The sealing portion is connected to the bottom end of the connecting portion and abuts against the top end of the casing hanger. The outer wall of the sealing portion forms a sealing structure with the inner wall of the wellhead, and the inner wall of the sealing portion forms a sealing structure with the outer wall of the casing hanger. The first and second locking elements are located on the sealing assembly.

[0018] When the sealing assembly is installed downward along the axial direction of the casing hanger into the annulus, at least a portion of the connection is configured to move downward along the axial direction of the casing hanger, causing the second locking member to move radially to lock into the second locking part of the wellhead, and causing the first locking member to move radially to lock into the first locking part.

[0019] Thus, when the casing hanger undergoes axial displacement due to thermal expansion, the top end of the casing hanger in the sealing device provided in this application can apply an axial force to the sealing part. This force can be transmitted through the sealing part to the connecting part and the second locking member, and then transmitted to the wellhead by the second locking member and the connecting part, thereby maintaining the reliability of locking and the contact stability of the sealing interface under thermal expansion conditions.

[0020] In addition, the sealing device of this application can achieve reliable locking of the sealing component in the annulus, sealing between the sealing component and the wellhead, and sealing between the sealing component and the casing hanger through a simple installation operation. This not only simplifies the installation process, reduces the number of operation steps, and improves installation efficiency and reliability, but also ensures that the sealing device maintains stable locking force and sealing performance in complex downhole conditions over a long period of time. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A cross-sectional view of the sealing component in the wellhead sealing device provided in an embodiment of this application;

[0023] Figure 2 A cross-sectional view of the sealing component in the wellhead sealing device provided in this application embodiment when it is installed between the wellhead and the casing hanger;

[0024] Figure 3 for Figure 1 Enlarged view of section A.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1-Sealing device; 2-Wellhead; 2a-Second locking part; 2b-Annulus; 2c-Third locking part;

[0027] 10-Sealing assembly; 20-Sleeve hanger; 20a-First locking part; 30-First locking element; 40-Second locking element;

[0028] 100 - Connecting part; 200 - Sealing part;

[0029] 110 - Moving part; 120 - Support part; 130 - Shear pin; 210 - First sealing section; 220 - Second sealing section;

[0030] 111-First moving section; 112-Second moving section; 113-Annular groove; 114-Locking ring; 211-Through section; 221-First part; 222-Second part; 223-Third part;

[0031] 1111 - Groove; 1112 - Third locking element; 1113 - Spring; 1121 - Locking groove; 1122 - Inclined surface; 2231 - Seal; 2232 - First protrusion; 2233 - Second protrusion; 2234 - Sealing groove; 2235 - Sealing ring;

[0032] X-center line. Detailed Implementation

[0033] As described in the background section, in offshore oil and gas drilling and production operations, the annular space between the wellhead and the casing hanger needs to be reliably sealed to isolate high-pressure downhole fluids, ensure drilling safety, and prevent environmental pollution. The sealing structure between the wellhead and the casing hanger needs to remain stable over a long period in the complex downhole environment of high temperature, high pressure, dynamic loads, and fluids containing impurities. Its sealing performance affects the safety of drilling operations, the effective isolation of oil and gas reservoirs, and the continuity and reliability of subsequent production processes.

[0034] In existing technologies, wellhead sealing devices typically separate the sealing assembly from the locking assembly structurally. This approach generally relies on adding a separate locking bushing or using a complex multi-stage locking ring assembly, requiring multiple separate installations and operations to ultimately achieve radial locking.

[0035] However, this design, which separates the sealing and locking functions, leads to complex installation procedures, requiring repeated use of specialized tools, which not only prolongs the operation cycle but also increases operating costs. Furthermore, when downhole temperature changes cause axial thermal expansion of the casing hanger, traditional locking structures struggle to ensure reliable maintenance of the locking force and stable contact with the sealing surface under continuous thermal stress, posing a risk of seal failure. In addition, existing sealing devices cannot simultaneously and reliably complete bidirectional locking of the wellhead interior and casing hanger exterior during a single axial pressing process, limiting the practical application of traditional sealing devices under high-efficiency, continuous operation requirements.

[0036] In view of this, embodiments of this application provide a sealing device for a wellhead.

[0037] The wellhead sealing device of this application includes a casing hanger and a sealing assembly, the sealing assembly being disposed within the annulus formed by the wellhead and the outer wall of the casing hanger. The sealing assembly includes a connecting part and a sealing part connected together, wherein the sealing part abuts against the top end of the casing hanger, and the inner wall and outer wall of the sealing part form sealing interfaces with the outer wall of the casing hanger and the inner wall of the wellhead, respectively.

[0038] The wellhead sealing device of this application also includes a second locking element and a first locking element. To solve the problem that traditional sealing devices cannot simultaneously achieve reliable bidirectional locking of the wellhead side and the casing hanger side during a single axial downward press, this application sets the second locking element and the first locking element on the outer wall and inner wall of the sealing assembly, respectively, so that the second locking element and the first locking element form an integrated structure with the sealing assembly, avoiding the cumbersome process of installing the second locking element and the first locking element separately.

[0039] When the sealing assembly is installed axially downward along the casing hanger into the annulus, at least a portion of the connecting part can move axially downward along the casing hanger, driving the second locking member to generate radial movement to lock into the second locking part on the wellhead, and simultaneously driving the first locking member to generate radial movement to lock into the first locking part on the casing hanger. In this way, the sealing device of this application can simultaneously achieve the sealing assembly reaching the preset installation position, establishing a seal with the wellhead and the casing hanger, and mechanical locking through a single axial downward pressing action, thereby simplifying the installation process and improving the synergy and reliability of the sealing and locking functions.

[0040] Furthermore, when the casing hanger undergoes axial displacement due to thermal expansion, the top end of the casing hanger in the sealing device provided in this application applies an axial force to the sealing part. This force can be transmitted through the sealing part to the connecting part and the second locking member, and then from the second locking member and the connecting part to the wellhead, thereby maintaining the reliability of the locking and the contact stability of the sealing interface under thermal expansion conditions.

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] Figure 1 A cross-sectional view of the sealing component in the wellhead sealing device provided in the embodiments of this application. Figure 2 A cross-sectional view of the sealing component in the wellhead sealing device provided in this application embodiment, when the sealing component is installed between the wellhead and the casing hanger.

[0043] Reference Figure 1 and Figure 2 This application provides a wellhead sealing device 1 (hereinafter referred to as sealing device 1). The sealing device 1 provided in this application can be applied to subsea wellhead systems in offshore oil and gas drilling and production projects. Exemplarily, the sealing device 1 can be used during drilling or production processes to seal off downhole high-pressure fluids, adapting to complex working conditions such as downhole high-temperature and high-pressure environments, dynamic loads, and the possible presence of drilling fluid solid phase impurities.

[0044] Alternatively, the sealing device 1 can also be used in comprehensive marine resource development scenarios accompanying the laying and maintenance of submarine cables. Near submarine cable routes that require power and signal transmission for offshore platforms or subsea production systems, the sealing device 1 can ensure a long-term reliable seal between the wellhead and the casing annulus under high pressure, corrosion, and impurity conditions, isolate downhole fluids, ensure the safety of drilling and production operations, and provide reliable environmental protection for the stable operation of nearby submarine infrastructure such as submarine cables.

[0045] The above is merely an illustrative description of the application scenario of the sealing device 1 in the embodiments of this application, and is not intended to limit the application scenario of the sealing device 1 in the embodiments of this application.

[0046] Reference Figure 2 The sealing device 1 provided in this application includes a sealing assembly 10 and a casing hanger 20. In the figure, X is the axial center line of the sealing assembly 10 and the casing hanger 20 provided in this embodiment. The casing hanger 20 is fixedly installed inside the wellhead 2, and an annular space 2b is formed between the outer wall of the casing hanger 20 and the inner wall of the wellhead 2. The top end of the casing hanger 20 can provide support for the sealing assembly 10 in the axial direction of the casing hanger 20. The sealing assembly 10 can be disposed in the annular space 2b to achieve a seal between the inner wall of the wellhead 2 and the outer wall of the casing hanger 20.

[0047] The sealing assembly 10 includes a connecting portion 100 and a sealing portion 200 connected to each other. The sealing portion 200 is connected to the bottom end of the connecting portion 100, and the sealing portion 200 abuts against the top end of the sleeve hanger 20 to achieve axial positioning of the sealing portion 200.

[0048] In this design, a seal is formed between the outer wall of the sealing part 200 and the inner wall of the wellhead 2, and a seal is also formed between the inner wall of the sealing part 200 and the outer wall of the casing hanger 20. Thus, the seals established by the sealing part 200 with both the wellhead 2 and the casing hanger 20 isolate the annulus 2b between the wellhead 2 and the casing hanger 20, blocking the flow of high-pressure fluids downhole. This allows the sealing device 1 of this application to prevent oil and gas leakage and ensure the sealing integrity of the wellhead 2 and operational safety under the harsh conditions of continuous high temperature, high pressure, and dynamic loads encountered in offshore drilling and production.

[0049] The sealing device 1 also includes a first locking member 30 and a second locking member 40, which are disposed on the sealing assembly 10. The outer wall of the casing hanger 20 forms a first locking portion 20a, into which the first locking member 30 can be locked, thereby achieving radial mechanical locking between the sealing assembly 10 and the casing hanger 20. The inner wall of the wellhead 2 forms a second locking portion 2a, into which the second locking member 40 can be locked, achieving radial mechanical locking between the sealing assembly 10 and the wellhead 2.

[0050] Specifically, when the sealing assembly 10 is installed downward along the axial direction of the casing hanger 20 into the annulus 2b, at least a portion of the connecting portion 100 can move downward along the axial direction of the casing hanger 20, causing the second locking member 40 to move radially outward and lock into the second locking portion 2a of the wellhead 2. Simultaneously, the downward movement of at least a portion of the connecting portion 100 along the axial direction of the casing hanger 20 can also cause the first locking member 30 to move radially inward to lock into the first locking portion 20a.

[0051] Thus, by applying an axial load to the connecting portion 100, the sealing device 1 of this application can drive the connecting portion 100 to generate displacement in the axial direction along the casing hanger 20, and drive the first locking member 30 and the second locking member 40 to perform radial locking movement. Therefore, the sealing assembly 10 of this application can simultaneously achieve reliable locking of the sealing assembly 10 within the annulus 2b, sealing between the sealing assembly 10 and the wellhead 2, and sealing between the sealing assembly 10 and the casing hanger 20 through a single simple installation operation. This configuration not only simplifies the installation process, reduces operational steps, and improves installation efficiency and reliability, but also ensures that the sealing device 1 maintains stable locking force and sealing performance over a long period in complex downhole conditions.

[0052] In some embodiments, to enhance the structural load-bearing capacity under extreme loads such as thermal expansion, the load-bearing surface of the first locking member 30 cooperating with the first locking part 20a can be composed of two axially adjacent inclined sections. Similarly, the load-bearing surface of the second locking member 40 cooperating with the second locking part 2a can also be composed of two axially adjacent inclined sections. In this way, the double-inclined structure of the first locking member 30 and the second locking member 40 can increase the load-bearing contact area, more evenly disperse and guide the axial force transmitted from the casing hanger 20 into the wellhead 2 body, thereby improving the structural load-bearing capacity and stability under continuous thermal stress, and avoiding damage to the sealing assembly 10 or locking failure due to stress concentration.

[0053] The materials of the first locking member 30 and the second locking member 40 can be selected according to the different requirements for bearing capacity based on different well depths, pressure levels, and operating conditions. For example, the first locking member 30 and the second locking member 40 can be made of high-strength alloy steel or materials with excellent toughness and corrosion resistance; this application embodiment does not impose specific limitations in this regard.

[0054] In some embodiments, the connecting portion 100 may include a movable portion 110 and a supporting portion 120 connected to each other. The supporting portion 120 is connected to the sealing portion 200. The movable portion 110 can move relative to the supporting portion 120 along the axial direction of the sleeve hanger 20, and drive the first locking member 30 and the second locking member 40 to generate radial movement, thereby realizing the locking function of the first locking member 30 and the second locking member 40.

[0055] In this embodiment, the radial movement of the first locking member 30 can be an inward positional movement of the first locking member 30 as a whole, or it can be a shape change of the first locking member 30 along the radial direction.

[0056] Of course, the radial movement of the second locking member 40 can be an outward positional movement of the second locking member 40 as a whole, or it can be a shape change of the second locking member 40 in the radial direction.

[0057] To enable axial movement of the moving part 110 relative to the supporting part 120, the moving part 110 and the supporting part 120 can be connected by a mechanical connection structure that is capable of failing under a predetermined axial load. Thus, during the initial installation phase, the moving part 110 and the supporting part 120 can be fixed as a single unit, allowing them to be lowered together into the annulus 2b. When the axial load applied to the moving part 110 reaches a preset threshold, the connection structure between the moving part 110 and the supporting part 120 breaks or separates, thereby releasing the rigid connection between the moving part 110 and the supporting part 120, allowing the moving part 110 to continue moving axially along the sleeve hanger 20 relative to the supporting part 120.

[0058] For example, the moving part 110 and the support part 120 can be connected by a shear pin 130. The shear pin 130 passes through pin holes corresponding to those in the moving part 110 and the support part 120, providing a reliable rigid connection during the initial stage of installation of the sealing assembly 10. When the axial force applied to the moving part 110 exceeds the shear strength of the shear pin 130, the shear pin 130 undergoes shear failure, and the moving part 110 then unlocks from the support part 120 and gains the freedom to move downward relative to the support part 120.

[0059] The movable part 110 may include a first movable segment 111 and a second movable segment 112, with at least a portion of the first movable segment 111 detachably connected to the inner wall of the second movable segment 112. Thus, when assembling the sealing assembly 10, the support part 120 can be first inserted into a predetermined position from the top of the second movable segment 112. After the support part 120 is in place, the first movable segment 111 and the second movable segment 112 are then connected. This arrangement avoids spatial interference between the first movable segment 111 and the support part 120 during the assembly of the sealing assembly 10, thereby ensuring that the support part 120 can be smoothly installed.

[0060] For example, the moving part 110 may further include a locking ring 114, through which the first moving segment 111 and the second moving segment 112 can be connected. The outer wall of the first moving segment 111 and the inner wall of the second moving segment 112 can be respectively constructed to form annular grooves 113. The locking ring 114 is disposed in the annular grooves 113. By radially contracting or expanding the locking ring 114, the first moving segment 111 and the second moving segment 112 can be quickly assembled and locked, restricting the axial relative movement between the first moving segment 111 and the second moving segment 112. In this way, the locking ring 114 can reliably fix the first moving segment 111 and the second moving segment 112 within a limited space, resulting in a compact structure and strong load-bearing capacity.

[0061] The inner wall of the first moving section 111 can be constructed as a wear-resistant working surface. In this way, the sealing component 10 of this application can integrate wear-resistant protection function itself, and after being installed in the annulus 2b, it can directly withstand the contact and passage of drill pipe or subsequent drilling tools, thereby eliminating the need to install an additional independent wear-resistant component on top of the sealing device 1, simplifying the operation process, and reducing the operational complexity and cost caused by the installation of multiple components.

[0062] The support portion 120 is connected to the inner wall of the second movable segment 112, and the support portion 120 is located at the end of the second movable segment 112 near the sleeve hanger 20. Exemplarily, the support portion 120 and the movable segment 110 can be connected by a shear pin 130. A gap is reserved between the support portion 120 and the first movable segment 111 along the axial direction of the sleeve hanger 20. This gap provides relative displacement space for the axial movement of the first movable segment 111 and the second movable segment 112 relative to the support portion 120.

[0063] When the sealing assembly 10 is installed downward along the axial direction of the sleeve hanger 20 to the annulus 2b, an axial load is applied to the first moving section 111. When the axial force applied to the first moving section 111 exceeds the shear strength of the shear pin 130, the shear pin 130 is sheared and broken. The first moving section 111 and the second moving section 112 can then move axially synchronously relative to the support 120 until the bottom end of the first moving section 111 abuts against the top end of the support 120.

[0064] Continue to refer to Figure 1 and Figure 2 The second locking member 40 abuts against the outer wall of the second moving section 112, and the second locking member 40 abuts against the top end of the sealing part 200. The first locking member 30 is located on the inner wall of the sealing part 200, and the first locking member 30 is located at the bottom end of the second moving section 112.

[0065] In some possible implementations, the outer wall of the second moving segment 112 may be configured to form a locking groove 1121, within which at least a portion of the second locking member 40 is located. The locking groove 1121 provides accommodating space for the second locking member 40, ensuring that the second locking member 40 remains in a preset position when not driven by the second moving member, thus preventing unintended displacement in the circumferential or axial direction.

[0066] The end of the locking groove 1121 facing away from the sleeve hanger 20 can be an inclined surface 1122. The inclined surface 1122 can guide the radial movement of the second locking member 40, avoiding interference between the second locking member 40 and the second moving section 112, thereby ensuring the continuity of the installation process of the sealing assembly 10.

[0067] Continue to refer to Figure 1 and Figure 2 The sealing part 200 includes a first sealing section 210, which abuts against the top end of the sleeve hanger 20. In this way, the sleeve hanger 20 can provide a stable axial positioning and support reference for the sealing assembly 10.

[0068] A through portion 211 is formed on at least a portion of the cylindrical wall of the first sealing section 210, extending axially along the sleeve hanger 20, and providing a passage for the second moving section 112. The second moving section 112 can pass through the through portion 211 axially along the sleeve hanger 20 and contact the first locking member 30.

[0069] The sealing portion 200 also includes a second sealing section 220, which is connected to the outer wall of the through portion 211. A second locking member 40 is located at the top end of the second sealing section 220, and a first locking member 30 is located on the inner wall of the second sealing section 220.

[0070] In some possible embodiments, the second sealing section 220 includes a first portion 221 and a second portion 222 connected together. The first portion 221 is connected to the outer wall of the through portion 211, and the first locking member 30 is located at the top of the first portion 221. The second portion 222 is located at the bottom of the first sealing section 210. Along the axial direction of the wellhead 2, there is a gap between the second portion 222 and the first sealing section 210. The inner diameter of the second portion 222 is smaller than the inner diameter of the first portion 221, thereby forming a stepped bearing surface at the connection between the second portion 222 and the first portion 221. The first locking member 30 is located on the bearing surface, and the first locking member 30 can provide stable and reliable positioning and support for the bearing surface. The bottom end of the second moving section 112 is located above the bearing surface.

[0071] When the second moving section 112 moves axially downward relative to the support part 120, the outer wall of the second moving section 112 contacts the second locking member 40 and slides relative to it, thereby applying a radially outward driving force to the second locking member 40, causing the second locking member 40 to move radially outward and lock into the second locking part 2a on the inner wall of the wellhead 2.

[0072] Simultaneously, the bottom end of the second moving section 112 passes through the through portion 211 during its downward movement and contacts the first locking member 30 located on the bearing surface, causing the first locking member 30 to move radially inward, thus locking the first locking member 30 into the first locking portion 20a on the outer wall of the casing hanger 20. Therefore, through the axial displacement of the second moving section 112, coordinated locking between the sealing assembly 10 and the wellhead 2, as well as between the sealing assembly 10 and the casing hanger 20, can be achieved simultaneously.

[0073] Reference Figure 2The inner wall of the wellhead can also be configured to form a third locking part 2c, and the outer wall of the first moving section 111 can be configured to form a groove 1111, in which a third locking element 1112 is provided. When the second moving section 112 moves along the axial direction of the casing hanger 20 to the preset installation position, the third locking element 1112 can be embedded in the third locking part 2c. Through the cooperation of the third locking element 1112 and the third locking part 2c, the unexpected upward displacement of the moving part 110 due to downhole vibration or pressure fluctuations after installation can be further restrained, thereby preventing the first locking element 30 from loosening from the first locking part 20a or the second locking element 40 from loosening from the second locking part 2a, ensuring the long-term reliability and stability of the locking state of the sealing assembly 10.

[0074] In some embodiments, the third locking member 1112 can be elastically connected to the groove 1111 by a spring 1113. During the downward movement of the first moving section 111, the inner wall of the wellhead applies radial pressure to the third locking member 1112, causing the third locking member 1112 to compress the spring 1113 and be completely retracted into the groove 1111. When the first moving section 111 moves to a preset position and the groove 1111 aligns with the third locking part 2c, the spring 1113 releases its elastic force, pushing the third locking member 1112 radially out of the groove 1111 and causing the third locking member 1112 to embed into the third locking part 2c, thereby achieving automatic mechanical locking after the first moving section 111 is installed.

[0075] In some embodiments, the sealing part 200 may further include a third part 223, which is connected to the bottom end of the second part 222 and is fitted into the annulus 2b between the wellhead 2 and the casing hanger 20.

[0076] Figure 3 for Figure 1 A magnified view of section A. (Refer to...) Figure 3 Multiple sealing elements 2231 may be provided between the outer wall of the third part 223 and the inner wall of the wellhead 2, and between the inner wall of the third part 223 and the outer wall of the casing hanger 20. The sealing elements 2231 may be made of elastic materials such as rubber.

[0077] When the third part 223 is installed in the annulus 2b, the seal 2231 can undergo elastic compression deformation between the third part 223 and the wellhead 2, thereby forming an initial seal between the third part 223 and the wellhead 2. At the same time, the seal 2231 can also undergo elastic compression deformation between the third part 223 and the casing hanger 20, thereby forming an initial seal between the third part 223 and the casing hanger 20.

[0078] Furthermore, the inner wall of the third part 223 may be configured to form a first protrusion 2232 that protrudes radially inward along the third part 223, and the outer wall of the third part 223 may be configured to form a second protrusion 2233 that protrudes radially outward along the third part 223. The outer wall of the third part 223 may be configured to form a sealing groove 2234, in which a sealing ring 2235 is provided.

[0079] When the third part 223 is installed into the annulus 2b, the first protrusion 2232 comes into contact with and is squeezed against the outer wall of the casing hanger 20, forcing the third part 223 to undergo radial outward elastic deformation, thereby causing the second protrusion 2233 and the sealing ring 2235 to fit tightly against the inner wall of the wellhead 2, and finally forming a reliable high-pressure sealing barrier in the annulus 2b between the wellhead 2 and the casing hanger 20.

[0080] To ensure that the contact compression between the first protrusion 2232 and the sleeve hanger 20 can be effectively converted into the sealing and pressing action of the second protrusion 2233 and the sealing ring 2235 through the deformation of the third part 223, the first protrusion 2232 can be radially corresponding to the second protrusion 2233 and the sealing groove 2234.

[0081] In some possible implementations, multiple first protrusions 2232, second protrusions 2233, and sealing grooves 2234 can be provided along the axial direction of the third portion 223. The multiple first protrusions 2232 arranged along the axial direction of the third portion 223 can continuously contact and compress with the outer wall of the sleeve hanger 20. This allows the third portion 223 to generate the required radially outward elastic deformation more evenly over a longer axial range.

[0082] Multiple second protrusions 2233 and sealing grooves 2234 can form multiple sealing barriers distributed axially along the third part 223, thereby achieving a multi-level sealing effect, enhancing the overall reliability and fault tolerance of the sealing device 1, and adapting to the axial irregularities that may exist in the annulus 2b as well as complex axial and radial composite loads.

[0083] When the sealing assembly 10 provided in this application is installed into the annulus 2b, an axial load is applied to the first moving section 111, driving the second moving section 112 to move downward. The inclined surface 1122 of the second moving section 112 interacts with the second locking member 40, causing the second locking member 40 to move radially and lock into the second locking part 2a; simultaneously, the bottom end of the second moving section 112 pushes the first locking member 30 to move radially and lock into the first locking part 20a. Thus, the sealing assembly 10 provided in this application can complete bidirectional locking and sealing with the wellhead 2 and the casing hanger 20 in one continuous operation.

[0084] In complex conditions where impurities such as mud and debris increase frictional resistance within the annulus 2b, the sealing assembly 10 of this application can be installed with hydraulic pressure assistance to ensure reliability. First, the sealing assembly 10 is pressed down using an installation tool, causing the seals 2231 on the third part 223 to contact the sealing surfaces of the wellhead 2 and the casing hanger 20, forming an initial seal to isolate the annulus. Subsequently, hydraulic pressure is injected into the annulus through the blowout preventer (BOP) system. The hydraulic pressure, combined with the downward pressure of the installation tool, provides a greater axial driving force, ensuring that the sealing assembly 10 can overcome external resistance and continue downward until it is fully installed and finally locked.

[0085] It should be noted that the terms "an embodiment," "an embodiment," "an exemplary embodiment," "some embodiments," etc., mentioned in the specification may include specific features, structures, or characteristics, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Additionally, when describing a specific feature, structure, or characteristic in conjunction with embodiments, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0086] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "one" can be understood to convey either singular or plural usage.

[0087] It should be readily understood that the terms “on,” “above,” and “on top of” in this application should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on something” but also “on something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0088] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90° or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A sealing device for a wellhead, characterized in that, include: A casing hanger is configured to be installed at the wellhead such that an annulus is formed between the outer wall of the casing hanger and the inner wall of the wellhead, and the outer wall of the casing hanger is configured to form a first locking part. A sealing assembly is disposed within the annulus. The sealing assembly includes a connecting part and a sealing part connected together. The sealing part is connected to the bottom end of the connecting part and abuts against the top end of the casing hanger. The outer wall of the sealing part is used to form a sealing structure with the inner wall of the wellhead, and the inner wall of the sealing part is used to form a sealing structure with the outer wall of the casing hanger. A first locking member and a second locking member are located on the sealing assembly; when the sealing assembly is installed downward along the axial direction of the casing hanger to the annulus, at least a portion of the connecting portion is configured to move downward along the axial direction of the casing hanger, causing the second locking member to move radially to lock into the second locking portion of the wellhead, and causing the first locking member to move radially to lock into the first locking portion.

2. The sealing device according to claim 1, characterized in that, The connecting part includes a movable part and a supporting part connected to each other; the supporting part is connected to the sealing part; the movable part is configured to move axially relative to the supporting part to drive the first locking member and the second locking member to move radially.

3. The sealing device according to claim 2, characterized in that, The movable part includes a first movable segment and a second movable segment, wherein at least a portion of the first movable segment is detachably connected to the inner wall of the second movable segment; The support is connected to the inner wall of the second moving section, and the support is located at one end of the second moving section near the sleeve hanger; along the axial direction of the sleeve hanger, there is a gap between the support and the first moving section, and both the first moving section and the second moving section are configured to move axially relative to the support until the bottom end of the first moving section abuts against the top end of the support. The second locking member abuts against the outer wall of the second moving section, and the second locking member abuts against the top end of the sealing part; the first locking member is located on the inner wall of the sealing part, and the first locking member is located at the bottom end of the second moving section.

4. The sealing device according to claim 3, characterized in that, The outer wall of the second moving segment is configured to form a locking groove, and at least a portion of the second locking member is located within the locking groove.

5. The sealing device according to claim 4, characterized in that, The locking groove is inclined at the end opposite to the sleeve hanger.

6. The sealing device according to claim 3, characterized in that, The second moving segment and the support portion are connected by shear pins; When the first moving segment is subjected to an axially downward force, the shear pin is sheared, causing the second moving segment to move axially downward relative to the support portion and drive the second locking member to generate radial movement to lock into the second locking portion; at the same time, the bottom end of the second moving segment contacts the first locking member and drives the first locking member to generate radial movement to lock into the first locking portion.

7. The sealing device according to claim 3, characterized in that, The sealing portion includes a first sealing section abutting against the top end of the sleeve hanger; at least a portion of the cylindrical wall of the first sealing section is configured to form a through portion extending axially along the sleeve hanger, such that the second moving section passes through the through portion axially along the sleeve hanger and abuts against the first locking member.

8. The sealing device according to claim 7, characterized in that, The sealing part further includes a second sealing section, which is connected to the outer wall of the through part; The second locking member is located at the top of the second sealing section, and the first locking member is located on the inner wall of the second sealing section.

9. The sealing device according to claim 8, characterized in that, The second sealing section includes a first part and a second part connected to each other, the first part being connected to the outer wall of the through part; the first locking member is located at the top of the first part; The second part is located at the bottom end of the first sealing section along the axial direction of the wellhead. There is a gap between the second part and the first sealing section. The inner diameter of the second part is smaller than the inner diameter of the first part. The connection between the second part and the first part forms a bearing surface. The first locking member is located on the bearing surface.

10. The sealing device according to claim 9, characterized in that, The second sealing section further includes a third part, which is connected to the bottom end of the second part; The third part is sleeved between the wellhead and the casing hanger, and multiple sealing elements are respectively provided between the third part and the casing hanger, and between the third part and the wellhead.

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