Mandrel type hanger with replaceable sealing assembly

Abstract

The utility model discloses a mandrel type hanger with a replaceable sealing assembly, and relates to the technical field of oil and gas exploitation equipment, the mandrel type hanger comprises a hanger body, the hanger body is outwards provided with a protruding limiting step along the radial direction, a metal sealing assembly is arranged above the limiting step, the limiting step is annular, and the metal sealing assembly is arranged on the hanger body. A first sealing piece is arranged below the limiting step and used for protecting the first sealing piece, and overload failure of the first sealing piece is avoided. According to the hanger sealing structure provided by the utility model, the metal sealing assembly is arranged above the hanger sealing structure, so that the hanger sealing structure can be mounted after a casing pipe is put down and the hanger is set, the problem that a metal sealing piece is damaged and fails in the putting process is effectively avoided, the sealing performance of the hanger is improved, and the service life of the hanger is prolonged; and the hanger sealing structure provided by the utility model enables the sealing part to be easy to clean.

Description

Technical Field

[0001] The utility model belongs to the technical field of oil and gas production equipment, and particularly relates to a mandrel type hanger with a replaceable seal assembly. Background Technique

[0002] The casing head is the basic part of the wellhead device, including the casing head body, hanger, packing device, jackscrew, gate valve, pressure gauge, etc., which is used to hang each layer of casing in the well and seal the annular space between the casings, and provide a transition connection for installing blowout preventers, tubing heads, Christmas trees, etc. Among them, the main function of the hanger is to hang various tools in the oil well in an appropriate position to ensure the smooth progress of operations such as drilling, completion, and oil production. Therefore, the sealing performance of the hanger is crucial for its normal operation, because it directly affects the safety and production efficiency of the oil well. Good sealing performance can prevent the fluid in the oil well from leaking, avoiding environmental pollution and resource waste. At the same time, a hanger with good sealing performance can also ensure the pressure stability of the oil well and improve the oil production efficiency.

[0003] The traditional sealing structure of the mandrel type hanger generally adopts a combination form with rubber sealing in the upper part and metal sealing in the lower part. This design can meet the sealing requirements of the hanger to a certain extent. Rubber sealing has good elasticity and sealing performance and can adapt to different pressure and temperature conditions. Metal sealing has high strength and wear resistance, which can ensure the reliability of the seal. However, this design also has some limitations. For example, the hanger adopts an integral installation mode. During the lowering process, if there is an obstruction or collision, the metal seal is easily damaged by knocking, resulting in a decrease in sealing performance or even failure. Since the metal seal is located in the lower part, it is relatively difficult to clean. After long-term use, a large amount of foreign matter such as cuttings may adhere to the sealing part, and these foreign matters will affect the sealing effect of the seal, thereby affecting the normal operation of the hanger. If the sealing effect is not good, it may cause the fluid in the oil well to leak, affecting the production efficiency and safety of the oil well.

[0004] Therefore, there is an urgent need for a mandrel type hanger with a replaceable seal assembly to improve the sealing performance and reliability of the hanger. Content of the Utility Model

[0005] The purpose of the utility model is to provide a mandrel type hanger with a replaceable seal assembly, which realizes the replaceability of the seal assembly, eliminates the bite damage to the outer wall of the casing caused by the traditional slip-on setting structure, reduces the risk of fracture and failure of the wellhead casing, and at the same time avoids the problem that the traditional rubber seal is easy to age and fail, so as to overcome the deficiencies that the hanger of the existing technology is integrally installed and is easily knocked during the lowering process, resulting in a decrease in sealing performance or even failure, and the metal seal is located in the lower part and is relatively difficult to clean.

[0006] To achieve the above object, the utility model adopts the following technical solutions:

[0007] A mandrel hanger with a replaceable seal assembly, comprising a hanger body. The hanger body is provided with a protruding limit step along the radial outward direction. Above the limit step, a metal seal assembly is provided. The limit step is annular, and a first seal is provided below the limit step to protect the first seal from overloading and failure.

[0008] Furthermore, a pressure accumulation groove is provided on the surface of the limit step facing the metal seal assembly. The metal seal assembly is arranged above the pressure accumulation groove, and the pressure accumulation groove communicates with the injection hole of the casing head body.

[0009] Furthermore, the metal seal assembly includes a gasket ring and a seal ring, and a seal ring is embedded between the two gasket rings.

[0010] Furthermore, a support assembly is provided below the first seal.

[0011] Furthermore, the support assembly includes a support ring and a union nut; the support ring is used to support the first seal, and the union nut is arranged below the support ring to fix the support ring.

[0012] Furthermore, at least one second seal is provided on the outer wall of the limit step.

[0013] Furthermore, the first seal is a rectangular seal.

[0014] Furthermore, the first seal and the second seal are spring-skeleton type ESS rings.

[0015] Furthermore, the hanger body is made of corrosion-resistant alloy.

[0016] Furthermore, the seal ring is made of stainless steel.

[0017] Compared with the prior art, the utility model has the following beneficial technical effects:

[0018] The present invention provides a mandrel-type hanger with a replaceable seal assembly. Compared to conventional mandrel-type hanger seal structures, the hanger utilizes an integral installation design. If the hanger encounters obstacles or collisions during lowering, the metal seal is easily damaged, resulting in reduced sealing performance or even complete failure. The present invention provides a hanger seal structure in which the metal seal assembly is positioned above the hanger, allowing installation after the casing is lowered and the hanger is set. This effectively prevents damage and failure of the metal seal during lowering, thereby improving the hanger's sealing performance and service life. Furthermore, the present invention facilitates cleaning of the seal area. In conventional hangers, the metal seal is located at the bottom, making cleaning extremely difficult. After prolonged use, the seal area may become clogged with debris and other foreign matter. This foreign matter can severely affect the seal's effectiveness, negatively impacting the hanger's proper operation. The hanger of this utility model, however, positions the metal seal assembly at the top, making cleaning more convenient and efficient. This prevents debris and other foreign matter adhering to the inner wall of the casing head from affecting the seal's sealing performance, ensuring that the hanger maintains excellent sealing performance during use, providing a reliable guarantee for the smooth progress of operations such as oil extraction. The hanger seal structure provided by this utility model adopts a split design. If the metal seal assembly is damaged or fails, it can be quickly replaced through the pressure accumulator without having to replace the entire hanger, significantly reducing maintenance costs and workload.

[0019] Specifically, with conventional mandrel hangers, if the seal performance does not meet requirements or fails during a pressure test after the hanger is installed and secured, it is difficult to take countermeasures to improve the sealing structure. However, the present invention places a pressure accumulator below the metal seal assembly. When the hanger body is inserted into the casing head body, the pressure accumulator connects to the pressure injection port of the casing head body. If the pressure test fails, the metal seal assembly can be ejected using grease injection pressure, enabling rapid replacement of the upper metal seal assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a structural schematic diagram of a sealing structure of a mandrel-type hanger with a replaceable sealing assembly in an embodiment of the present invention.

[0021] Figure 2 This is a schematic structural diagram of a pressure storage tank of a mandrel-type hanger with a replaceable sealing assembly in an embodiment of the present invention.

[0022] In the figure, 1, hanger body; 2, limit step; 3, pressure storage tank; 4, pressure injection hole; 5, gasket; 6, sealing ring; 7, first sealing member; 8, support ring; 9, cap; 10, second sealing member. DETAILED DESCRIPTION

[0023] To enable those skilled in the art to better understand the solution of the present utility model, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0024] It should be noted that the terms "first", "second", etc. in the description and claims of the present utility model and the above-mentioned accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present utility model described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0025] The present utility model provides a mandrel type hanger with a replaceable seal assembly, which realizes the replaceability of the seal assembly, eliminates the bite damage to the outer wall of the casing caused by the traditional slip type setting and hanging structure, reduces the risk of fracture failure of the wellhead casing, and at the same time avoids the problem of easy aging and failure of the traditional rubber seal.

[0026] Refer to Figures 1 to 2 , a mandrel type hanger with a replaceable seal assembly, including a hanger body 1. Taking the installation direction of the hanger body 1 as a reference, the hanger body 1 is provided with a protruding limit step 2 along the radial outward direction. A metal seal assembly is arranged above the limit step 2, and a first seal 7 is arranged below the limit step 2.

[0027] In the embodiment of the present utility model, the limit step 2 is annular, arranged between the metal seal assembly and the first seal 7, and located above the first seal 7, for protecting the first seal 7 to avoid overloading and failure of the first seal 7.

[0028] In an embodiment of the present utility model, a pressure accumulation groove 3 is provided on the surface of the limiting step 2 facing the metal sealing assembly. The metal sealing assembly is disposed above the pressure accumulation groove 3, and the pressure accumulation groove 3 communicates with the injection hole 4 of the casing head body. For a traditional mandrel hanger, after the hanger is set and fixed, if it is found that its sealing performance does not meet the requirements or the seal fails during a pressure test, it is difficult to take countermeasures to improve its sealing performance for the sealing structure; in the embodiment of the present utility model, the pressure accumulation groove 3 is arranged below the metal sealing assembly. When the hanger body extends into the casing head body, the pressure accumulation groove 3 can communicate with the injection hole 4 of the casing head body. If the pressure test is unqualified, the metal sealing assembly can be pushed out by the grease injection pressure to achieve rapid replacement of the upper metal sealing assembly.

[0029] In an embodiment of the present utility model, the metal sealing assembly includes a gasket ring 5 and a sealing ring 6. One sealing ring 6 is embedded between the two gasket rings 5; the sealing ring 6 is an X-shaped metal sealing ring and can be made of 304 stainless steel, preferably 06Cr19Ni10 with good corrosion resistance, heat resistance, high and low temperature strength, and mechanical properties.

[0030] In an embodiment of the present utility model, a support assembly is provided below the first seal 7. The support assembly includes a support ring 8 and a union nut 9; the support ring 8 is used to support the first seal 7, and the union nut 9 is arranged below the support ring 8 to fix the support ring 8.

[0031] In an embodiment of the present utility model, at least one second seal 10 is embedded in the outer wall of the limiting step 2. The first seal 7 is a rectangular seal. The first seal 7 and the second seal 10 can be selected as O-ring seals made of rubber. For example, a highly saturated elastomer obtained by special hydrogenation treatment of nitrile rubber can be used. It has good oil resistance, relatively high corrosion resistance, wear resistance, and compression set resistance. Preferably, a spring skeleton type ESS seal with good rigidity, high pressure resistance, long service life, and stable sealing is used. It is made of hydrogenated nitrile rubber and stainless steel 316, which can further improve the sealing performance.

[0032] In an embodiment of the present utility model, the hanger body 1 is made of a corrosion-resistant alloy, preferably 718 corrosion-resistant alloy.

[0033] The mandrel hanger with a replaceable seal assembly provided by the embodiment of the present utility model optimizes the sealing structure of the traditional hanger. It adopts a structure with a rubber seal at the lower end and a metal seal assembly at the upper end. The metal seal assembly is installed after the casing is lowered and the hanger is set. Compared with the prior art, it can avoid the loss and failure of the metal seal during the lowering process of the hanger, can conveniently clean the sealing part before installing the metal seal assembly, and can effectively avoid the problem of reduced sealing performance caused by foreign substances attached to the sealing part, thereby improving the production efficiency of the oil well. Since the metal seal structure of the hanger of the present utility model adopts a split design, once the metal seal assembly is damaged or fails, it can be quickly replaced through the pressure accumulation groove without replacing the entire hanger, greatly reducing the maintenance cost and workload.

[0034] A casing head for the mandrel hanger provided by the present utility model further includes a casing head body. The casing head body has a pressure injection hole corresponding to the metal seal structure of the hanger. The pressure injection hole 4 is communicated with the pressure accumulation groove 3, and a plug is provided outside. When the pressure test is unqualified or the metal seal assembly of the hanger is damaged and fails, the metal seal assembly can be pushed out by the injection pressure to achieve the quick replacement of the upper metal seal assembly.

[0035] In the description of this specification, the description with reference to terms such as "some embodiments", "optionally", "further" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0036] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the claims and their equivalents.

Claims

1. A mandrel hanger with a replaceable sealing assembly, characterized in that, It includes a hanger body (1), the hanger body (1) is provided with a protruding limit step (2) arranged radially outward, a metal sealing assembly is arranged above the limit step (2), and a first seal (7) is arranged below the limit step (2).

2. The mandrel hanger with a replaceable seal assembly according to claim 1, characterized in that, The surface of the limit step (2) facing the metal sealing assembly is provided with a pressure accumulation groove (3), the metal sealing assembly is arranged above the pressure accumulation groove (3), and the pressure accumulation groove (3) is communicated with the injection hole (4) of the casing head body.

3. The mandrel hanger with a replaceable seal assembly according to claim 1, characterized in that, The metal sealing assembly includes a gasket ring (5) and a sealing ring (6), and a sealing ring (6) is embedded between the two gasket rings (5).

4. The mandrel hanger with a replaceable seal assembly according to claim 1, characterized in that, A support assembly is arranged below the first seal (7).

5. The mandrel hanger with a replaceable seal assembly according to claim 4, wherein, The support assembly includes a support ring (8) and a union nut (9); the support ring (8) is used to support the first seal (7), and the union nut (9) is arranged below the support ring (8) and is used to fix the support ring (8).

6. The mandrel hanger with a replaceable seal assembly according to claim 1, characterized in that, At least one second seal (10) is embedded in the outer wall of the limit step (2).

7. The mandrel hanger with a replaceable seal assembly according to claim 6, characterized in that, The first seal (7) is a rectangular seal.

8. The mandrel hanger with a replaceable seal assembly according to claim 7, characterized in that, The first seal (7) and the second seal (10) are spring-skeleton type ESS seals.

9. The mandrel hanger with a replaceable seal assembly according to claim 1, characterized in that, The hanger body (1) is made of corrosion-resistant alloy.

10. The mandrel hanger with a replaceable seal assembly according to claim 3, characterized in that, The sealing ring (6) is an X-type metal sealing ring, and the sealing ring (6) is made of stainless steel.

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