阅读说明：本技术 一种水下井口连接器复合式金属密封圈 (Underwater well head connector combined type metal sealing ring ) 是由 张崇 孟文波 任冠龙 董钊 黄亮 余意 王应好 陈才 于 2021-08-28 设计创作，主要内容包括：本发明提供一种水下井口连接器复合式金属密封圈,包括形状为环形的密封圈本体,密封圈本体包括球形外侧密封面和内侧平滑端面,其中两个所述球形外侧密封面以设置在密封圈本体外侧中心处的凸台对称设置,球形外侧密封面的端部有耐腐蚀合金垫层,而球形外侧密封面上还设有密封圈。通过球形外侧密封面内凹部设计可以防止密封圈在高温环境与采油树和井口头的锥面粘牢,便于密封圈的安装与拆卸,同时凸起部设计有利于与锥面进行密封时增加主密封的接触应力,提高密封性能。本发明的耐腐蚀合金垫层和密封圈组成的密封结构,保障主密封面在安装和拆卸过程不受损坏,结构简单,便于加工制造,特别适合海洋深部高压流体处的固定密封。(The invention provides an underwater wellhead connector composite metal sealing ring which comprises a sealing ring body in an annular shape, wherein the sealing ring body comprises spherical outer sealing surfaces and inner side smooth end surfaces, the two spherical outer sealing surfaces are symmetrically arranged by a boss arranged at the center of the outer side of the sealing ring body, the end part of the spherical outer sealing surface is provided with a corrosion-resistant alloy cushion layer, and the spherical outer sealing surface is also provided with a sealing ring. The design of the concave part in the sealing surface of the spherical outer side can prevent the sealing ring from being firmly adhered to the conical surfaces of the Christmas tree and the wellhead head in a high-temperature environment, so that the sealing ring is convenient to install and detach, and meanwhile, the design of the convex part is favorable for increasing the contact stress of the main seal when the sealing ring is sealed with the conical surfaces, and the sealing performance is improved. The sealing structure composed of the corrosion-resistant alloy cushion layer and the sealing ring ensures that the main sealing surface is not damaged in the mounting and dismounting processes, has a simple structure, is convenient to process and manufacture, and is particularly suitable for fixed sealing at the deep high-pressure fluid position of the ocean.)

1. The utility model provides an underwater wellhead connector combined type metal sealing ring, is annular sealing washer body (1) including the shape, its characterized in that:

the sealing ring body (1) comprises spherical outer side sealing surfaces (11) and inner side smooth end surfaces (12), wherein the two spherical outer side sealing surfaces (11) are symmetrically arranged by a boss (13) arranged at the center of the outer side of the sealing ring body (1), the end part of each spherical outer side sealing surface (11) is filled with a corrosion-resistant alloy cushion layer (14), and an auxiliary sealing ring (15) is further arranged on each spherical outer side sealing surface (11).

2. The underwater wellhead connector composite metal seal ring as claimed in claim 1, wherein: and a groove for installing an auxiliary sealing ring (15) is arranged at the position of the spherical outer sealing surface (11) close to the boss (13).

3. The underwater wellhead connector composite metal seal ring as claimed in claim 1, wherein: two concave parts (16) are arranged on the spherical outer sealing surface (11).

4. The underwater wellhead connector composite metal seal ring as claimed in claim 3, wherein: and a convex part (17) is arranged on the spherical outer sealing surface (11).

5. The underwater wellhead connector composite metal seal ring as claimed in claim 4, wherein: the convex part (17) is positioned between the two concave parts (16).

6. The underwater wellhead connector composite metal seal ring as claimed in claim 1, wherein: the corrosion-resistant alloy pad layer (14) is made of a material which is wear-resistant, corrosion-resistant and ductile.

7. The underwater wellhead connector composite metal seal ring as claimed in claim 6, wherein: the corrosion-resistant alloy cushion coat (14) is made of Ni825 material.

8. The underwater wellhead connector composite metal seal ring as claimed in claim 1, wherein: the material of the sealing ring body (1) is 316L.

Technical Field

The invention relates to the technical field of sealing rings, in particular to a composite metal sealing ring of an underwater wellhead connector.

Background

In recent years, as the development of marine oil and gas is continuously advanced to deep sea areas, the problems of deep water, high temperature and high pressure are more severe, and the sealing device of the underwater wellhead system is also tested. The conventional elastic sealing technology is mature, the cost is low, and the application is wide in the initial development stage; however, due to the property problem of the sealing material, the sealing material is easy to generate high-temperature degradation and chemical degradation, and the problems of fatigue caused by cyclic load, compression load mutation failure, shearing failure of an extrusion gap and the like cannot meet the sealing requirement of the underwater wellhead system at the present stage.

Aiming at the problems, the underwater horizontal Christmas tree wellhead is connected by a locking block type connector, namely, the Christmas tree body is connected with the wellhead head by adopting a connection mode of mutually meshing a plurality of locking block tooth grooves and a wellhead groove surface, and the connector and the wellhead are sealed by metal. The sealing ring for the underwater connector in China mainly adopts a standard sealing ring, and the pretightening force of the sealing ring is large, so that the sealing requirement of the actual working condition of the locking block type underwater connector cannot be met.

Disclosure of Invention

The invention aims to provide a composite metal sealing ring of an underwater wellhead connector, which aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

the utility model provides an underwater wellhead connector combined type metal sealing ring, includes that the shape is annular sealing ring body, wherein:

the sealing ring body comprises spherical outer sealing surfaces and inner smooth end surfaces, wherein the two spherical outer sealing surfaces are symmetrically arranged by a boss arranged at the center of the outer side of the sealing ring body, the end part of each spherical outer sealing surface is filled with a corrosion-resistant alloy cushion layer, and an auxiliary sealing ring is further arranged on each spherical outer sealing surface.

Preferably, a groove for installing an auxiliary sealing ring is formed in the position, close to the boss, of the spherical outer sealing surface.

Preferably, two concave parts are arranged on the spherical outer sealing surface.

Preferably, the spherical outer sealing surface is provided with a convex part.

Preferably, the raised portion is located between two recessed portions.

Preferably, the corrosion-resistant alloy backing layer is a wear-resistant, corrosion-resistant, and ductile material.

Preferably, the corrosion-resistant alloy cushion coat is a Ni825 material.

Preferably, the material of the sealing ring body is 316L.

Compared with the prior art, the invention has the beneficial effects that:

the sealing ring can be prevented from being firmly adhered to the Christmas tree and the conical surface of the wellhead head in a high-temperature environment through the design of the concave part on the sealing surface on the outer spherical side, so that the sealing ring is convenient to mount and dismount, and meanwhile, the arrangement of the convex part is beneficial to increasing the contact stress of the main seal when the sealing ring is sealed with the conical surface, and the sealing performance is improved. The sealing structure composed of the corrosion-resistant alloy cushion layer and the sealing ring ensures that the main sealing surface is not damaged in the mounting and dismounting processes, has a simple structure, is convenient to process and manufacture, and is particularly suitable for fixed sealing at the deep high-pressure fluid position of the ocean.

Drawings

FIG. 1 is a cross-sectional view of a seal ring body according to the present invention;

FIG. 2 is an overall front cross-sectional view of the completed installation of the seal of the present invention;

FIG. 3 is a schematic view of the installation and positioning of the upper part of the sealing element contacting the sealed conical surface first;

FIG. 4 is a schematic view of the installation and positioning of the lower portion of the sealing element of the present invention contacting the conical surface to be sealed first;

FIG. 5 is a schematic view of the seal assembly of the present invention shown in position;

FIG. 6 is a cloud chart of the whole equivalent stress of the sealing ring and the equivalent stress of the sealing ring body under the pre-tightening working condition;

FIG. 7 is a cloud chart of equivalent stress of a filling part and equivalent stress of an auxiliary sealing ring under a pre-tightening working condition;

FIG. 8 is a cloud chart of the contact stress of the upper auxiliary sealing ring and the contact stress of the lower auxiliary sealing ring under the pre-tightening working condition;

FIG. 9 is a cloud chart of the contact stress of the corrosion-resistant alloy pad layer positioned on the upper side and the contact stress of the corrosion-resistant alloy pad layer positioned on the lower side under the pre-tightening working condition;

FIG. 10 is a cloud chart of the overall equivalent stress of the seal ring and the equivalent stress of the seal ring body under the working condition;

FIG. 11 is a cloud chart of equivalent stress of a filling part and equivalent stress of an auxiliary sealing ring under a working condition;

FIG. 12 is a cloud plot of upper fill site contact stress and lower fill site contact stress under operating conditions;

fig. 13 is a cloud chart of the contact stress of the upper auxiliary seal ring and the contact stress of the lower auxiliary seal ring under the working condition.

In the figure: 1 sealing ring body, 11 spherical outside sealing surface, 12 inside smooth end surface, 13 boss, 14 corrosion-resistant alloy cushion layer, 15 auxiliary sealing ring, 16 concave part, 17 convex part, 200 subsea Christmas tree body, 300 subsea wellhead head and 400 subsea wellhead connector.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example (b):

referring to fig. 1, the present invention provides a technical solution:

the utility model provides an underwater wellhead connector combined type metal sealing ring, includes that the shape is annular sealing ring body 1, wherein:

the sealing ring body 1 comprises a spherical outer sealing surface 11 and an inner smooth end surface 12, wherein the spherical outer sealing surface 11 is symmetrically arranged by a boss 13 arranged at the center of the outer side of the sealing ring body 1, the spherical outer sealing surface 11 is an inclined surface, the spherical outer sealing surface 11 is splayed, the end part of the spherical outer sealing surface 11 is filled with a corrosion-resistant alloy cushion layer 14, a groove for installing an auxiliary sealing ring 15 is arranged at the position, close to the boss 13, of the spherical outer sealing surface 11, the auxiliary sealing ring 15 is arranged in the groove, and therefore the auxiliary sealing effect is achieved, two inner concave parts 16 are arranged on the spherical outer sealing surface 11, a convex part 17 is arranged on the spherical outer sealing surface 11, and the convex part 17 is located between the two inner concave parts 16.

Preferably, the corrosion-resistant alloy backing layer 14 is a wear-resistant, corrosion-resistant, and ductile material, and the corrosion-resistant alloy backing layer 14 is preferably a Ni825 material.

Preferably, the material of the sealing ring body 1 is 316L.

Preferably, the auxiliary sealing ring 15 is a nitrile oil-resistant rubber O-ring.

The composite metal sealing ring is used in such a manner that, as shown in fig. 2 to 5, the subsea tree body 200 is connected to the subsea wellhead head 300 through the subsea wellhead connector 400, and the sealing ring body 1 is disposed between the subsea tree body 200 and the subsea wellhead head 300, wherein the boss 13 is in contact with a gap between the tree body 200 and the subsea wellhead head 300, and the two spherical outer sealing surfaces 11 are in sealing contact with the inclined surfaces of the tree body 200 and the subsea wellhead head 300, respectively.

When the Christmas tree is installed, firstly, the spherical outer sealing surface 11 of the metal sealing ring positioned at the lower side is firstly contacted with the underwater wellhead head 300, and because of the protruding design of the lower auxiliary sealing ring 15, the conical surface of the underwater wellhead head 300 is firstly contacted with the auxiliary sealing ring 15, but is not contacted with the bulge part 17 which is used as the main sealing surface at the lower part, so that the damage is avoided. Under the action of gravity, the tree continues to be lowered until the lower portion of the subsea tree body 200 contacts the upper corrosion-resistant alloy mat 14, thereby protecting the raised portion 17, the upper portion of which serves as the primary sealing surface. Then, the metal sealing ring is positioned, starts to be compressed to generate initial pre-tightening pressure, and then locks the subsea tree body 200 and the subsea wellhead head 300. In underbalanced drilling, in order to prevent external fluid from flowing into the inside, a conical surface needs to be sealed, and the seal assembly uses a combination of a corrosion-resistant alloy cushion layer 14 and an auxiliary seal ring 15, so that the seal assembly can resist the difference between the internal pressure and the external pressure in two directions, thereby ensuring the sealing performance.

Finite element simulation verification feasibility:

1) method for judging sealing performance

For a metal seal portion:

referring to the GB150-2010 specifications and the like, the sealing ring meets the sealing premise that plastic deformation occurs; under the pre-tightening working condition, the maximum contact stress of the sealing ring is required to be ensured to be larger than the pre-tightening specific pressure; under the working condition, the maximum contact stress of the sealing ring is ensured to be larger than the product of the medium pressure and the sealing coefficient. According to specifications such as GB150-2010 and the like, the pre-tightening specific pressure of the stainless steel sealing ring is 179.3 MPa; the sealing coefficient was 6.5.

② for non-metal sealing parts:

under the working condition, the maximum contact stress is larger than the working pressure, and the sealing requirement can be considered to be met.

2) Structural strength evaluation method

Referring to ASME VIII-2 and other specifications, the equivalent stress of the sealing ring body is smaller than the allowable stress, and the local equivalent stress of the sealing part is smaller than the tensile strength of the material.

3) The sealing performance and the structural strength of the sealing ring of the invention

Under the pre-tightening working condition, the maximum equivalent stress occurs at the metal filling part, the value is 204.84MPa, and the plastic deformation of the filler is shown to occur due to the yield strength of the filler being 220MPa, namely the sealing condition is achieved; the filling position is safe since its tensile strength is 550 MPa. The upper and lower maximum contact stresses of 297.16MPa and 315.52MPa are greater than the specific sealing pressure value of 179.5MPa of GB150 standard, which shows that the sealing ring meets the sealing requirement under the pre-tightening working condition, as shown in the attached figures 6-9.

Under the working condition, the maximum equivalent stress occurs at the metal filling part, the value of the maximum equivalent stress is 348.02MPa, and the yield strength of the filler is 220MPa, so that the filler is plastically deformed, namely, the sealing condition is achieved; the filling position is safe since its tensile strength is 550 MPa. The upper and lower maximum contact stresses of 620.85MPa and 605.94MPa are greater than 6.5 times of the GB150 standard of medium pressure 448.5NPa, which shows that the sealing ring meets the sealing requirement under the working condition. For the nonmetal sealing ring, the key for judging the sealing capability of the nonmetal sealing ring is that the maximum contact stress is larger than the pressure of a medium; it can be seen from the figure that under the working condition, the maximum contact stresses of the upper and lower auxiliary sealing rings are 85.595MPa and 89.406MPa, respectively, which are greater than the medium pressure 69MPa, indicating that the auxiliary sealing ring can replace the filling part to realize sealing in case of failure of the filling part, as shown in fig. 10-13.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.