CN108104760A - One kind is used for tubing hanger end metal sealing structure - Google Patents

Abstract

The invention discloses a metal sealing structure for the end of the oil pipe hanger, which includes a sealing body, the sealing body is composed of a sealing body body and a metal sealing joint, and an elastic circlip, half of the elastic circlip is embedded in the sealing body In the outer end face of the body, there is a support ring, the support ring is arranged on the outside of the metal sealing joint, and a metal seal ring is arranged in the support ring, and the left and right sides of the metal seal ring are provided with Stress relief grooves, one of the stress relief grooves is arranged on the side close to the metal sealing joint, a pair of deformation grooves are provided on the left and right sides of the metal sealing ring, and the internal parts of the present invention can be interchanged with each other , No special tools are required for installation and disassembly, which is convenient for assembly, saves installation and debugging time, and reduces downtime to a minimum.

Description

A metal sealing structure for the end of the oil pipe hanger

technical field

The invention relates to a metal sealing structure, in particular to a metal sealing structure used for an oil pipe hanging end, and belongs to the technical field of petroleum production and processing.

Background technique

In land oil fields or offshore platforms, for high pressure, gas, and oil production or gas production wellhead devices containing corrosive media, for safety, a metal-to-metal seal is required between the end of the tubing hanger and the transition flange of the tubing head. The metal seal is a special sealing device composed of its own body and the sealed carrier. In the specification field of API 6A, the sealed carrier refers to the tubing head conversion flange and tubing hanger. In the wellhead installation of oil or gas production , There needs to be a fairly reliable seal between the end of the tubing hanger and the transition flange of the tubing head.

In the field of oil production or gas production wellhead devices, the metal seal at the end of the tubing hanger is an indispensable and important part. It not only has the ability to resist hydrogen sulfide and carbon dioxide corrosion, but also has the ability to withstand high pressure (liquid pressure or gas pressure) The sealing ability must meet the requirements of API6A and NACE MR0175 in terms of material selection. If it fails during use, serious leakage will occur and workover operations will be required. Therefore, the metal seal at the end of the tubing hanger is safe to use. It is very important to show up.

The metal seal at the end of the oil pipe hanger currently in use is an integral type with a relatively simple structure. From the appearance, it is a thin-walled tubular shape with a lip on the outer circle of the end. From the partial view of the lip, the lip The mouth is arc-shaped, and the metal seal is sealed with an arc-shaped lip. There is a circumferential groove in the middle of the outer circle of the metal seal that is convenient for disassembly with tools. The existence of this circumferential groove can also improve the overall metal seal. The ability to resist deformation under the action of external force, the working principle and existing problems of the metal seal at the end of the tubing hanger in use:

The fit between the end lip of the metal seal and the carrier is an interference fit, and the interference is too small. Although the deformation of the lip of the metal seal is elastic deformation, the ability to withstand internal pressure is not very high. If the amount is too large, the deformation at the lip of the metal sealing ring will change from elastic deformation to plastic deformation, and the ability to withstand internal pressure will fail. Therefore, it is very important to control the amount of interference. The maximum working pressure of the seal is 5000Psi.

The metal seals at the end of the oil pipe hanger currently in use are subjected to different test pressures on the outside and inside. The main reason is that the metal seal is a thin-walled part, and its wall thickness cannot be too thick due to the influence of the carrier to be sealed. According to the requirements of API6A, its hardness control must be within the range of HB187-237, so the material strength of the metal seal itself is not very high. When the external force of the metal seal is greater than the yield strength of the material, a certain part of the lip of the metal seal One place will be separated from the sealed carrier. When the metal seal is subjected to force, the lip of the metal seal will expand under the force, and the lip and the sealed carrier will be tightly attached. As the force increases, the bonding force will also increase, so the internal detection force is greater than the external detection force.

When installing and debugging at the wellhead, it is impossible to judge the sealing reliability of metal seals due to the difference between the external and internal test pressures. The metal seals at the end of the oil pipe hanger currently in use are disposable, and special tools are required for installation and disassembly. The installation requires the installer to have high operating skills, otherwise leakage will occur.

Contents of the invention

The object of the present invention is to provide a metal sealing structure for the end of the oil pipe hanger that can solve the above problems.

In order to achieve the above object, the present invention provides a metal sealing structure for the end of the oil pipe hanger, including a sealing body, the sealing body is composed of a sealing body body and a metal sealing joint, and a circlip, half of the circlip Inlaid in the outer end surface of the sealing body body, a support ring, the support ring is set on the outside of the metal sealing joint, a metal seal ring, the metal seal ring is set in the support ring, and the metal seal ring is arranged on the left and right Stress relief grooves are provided on both sides, one of the stress relief grooves is arranged on the side close to the metal sealing joint, and a pair of deformation grooves are provided on the left and right sides of the metal sealing ring.

The above-mentioned one is used in the metal sealing structure at the end of the oil pipe hanger, wherein the metal sealing ring is in the shape of a tube with a rhombus cross section, and the metal sealing ring seals through the rhombus cross section.

The above-mentioned one is used in the metal sealing structure at the end of the oil pipe hanger, wherein the stress relief groove and the deformation groove are both arranged with the center of the diamond-shaped cross-section of the metal sealing ring as the central symmetrical point.

The above-mentioned one is used in the metal sealing structure at the end of the oil pipe hanger, wherein the two opposite corners of the cross-section of the metal sealing ring are contact points, and the contact points are respectively in contact with the sealing body and the sealed carrier .

The above-mentioned one is used in the metal sealing structure at the end of the oil pipe hanger, wherein the deformation groove is arranged on the inner side of the stress relief groove, and both the stress relief groove and the deformation groove are arc grooves And the diameter of the stress relief groove is smaller than the diameter of the deformation groove.

The above-mentioned one is used in the metal sealing structure at the end of the oil pipe hanger, wherein the sealing body is a mandrel type sealing body.

The above-mentioned one is used in the metal sealing structure at the end of the oil pipe hanger, wherein the metal sealing joint is made of carbon steel, low alloy steel, 300 series stainless steel and corrosion-resistant alloy materials and has no connection with the sealing body body. seam connection.

The above-mentioned one is used in the metal sealing structure at the end of the oil pipe hanger, wherein, the outer end surface of the metal sealing ring and the contact surface of the support ring form an included angle, and the included angle is 5°-15° .

The beneficial effects of the present invention are: the metal sealing structure used for the end of the oil pipe hanger is not limited in size when used, and can be made into metal sealing ring joints of various specifications and sizes, and will not affect the pressure fluctuation. The quality of the seal; the main function of the metal seal joint is to provide and maintain a metal-to-metal seal. The metal seal joint can be used not only in the field of API6A, but also in other fields that require metal-to-metal sealing, and can be reused many times It does not need to be replaced with a new one; it can be sealed without providing a special groove; the structure is simple, the internal parts of the present invention can be interchanged with each other, and no special tools are required for installation and disassembly, which is convenient for assembly, saves installation and debugging time, and saves downtime Reduced to a minimum.

Description of drawings

Fig. 1 is a structural schematic diagram of a metal sealing structure for the end of a tubing hanger provided by an embodiment of the present invention;

Fig. 2 is the assembly diagram of support ring;

Fig. 3 is a structural schematic diagram of a metal sealing ring;

The marks of the parts in the drawings are as follows: 1. Sealing body body; 2. Metal sealing ring; 3. Support ring; 4. Retaining ring; 5. Metal sealing joint; 6. Stress relief groove; 7. Deformation groove; 8 ,Contact point.

Detailed ways

The present invention will be further illustrated below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

Example 1

As shown in Figures 1 to 3, a metal sealing structure for the end of the oil pipe hanger includes a sealing body, the sealing body is composed of a sealing body body 1 and a metal sealing joint 5, and the metal sealing joint 5 will not Reduce the strength of the sealed carrier, the circlip 4, half of the circlip 4 is embedded in the outer end surface of the sealing body 1, and the support ring 3, the support ring 3 is arranged on the outside of the metal sealing joint 5 , metal sealing ring 2, the metal sealing ring 2 is set in the support ring 3, the left and right sides of the metal sealing ring 2 are provided with stress relief grooves 6, and one of the stress relief grooves 6 is arranged near One side of the metal sealing joint 5, the left and right sides of the metal sealing ring 2 are provided with a pair of deformation grooves 7, and the sealing between the metal seal at the end of the tubing hanger and the inner surface of the sealed carrier belongs to the metal-to-metal seal. Its inner surface roughness is required to reach 0.4 microns.

Under the action of external force F, through the support ring 3, the force is transmitted to the metal sealing ring 2, and the contact point of the metal sealing ring 2 begins to deform. Through deformation, the two pairs of the metal sealing ring The corner contact points are respectively in contact with the carrier to form a seal. Using the difference in the force point, the contact point is given priority to force, that is to say, the contact point is first deformed under the action of the force; as the force increases, the contact point The force at the point is getting bigger and bigger, the deformation at the contact point is getting more and more sufficient, and the sealing is getting more and more reliable. Due to the existence of the stress relief groove and the unique distribution of the force, the body of the metal sealing ring 2 The force to bear is not large, so that the metal sealing ring 2 will not be damaged.

Example 2

On the basis of the above embodiments, the metal sealing ring 2 is tubular and its cross section is diamond-shaped, and the metal sealing ring 2 is sealed through the diamond-shaped cross section. The metal sealing ring 2 can withstand 30000Psi working pressure at normal temperature, Both the stress relief groove 6 and the deformation groove 7 are set at the center of the rhombic cross section of the metal seal ring 2 as a central symmetrical point, the deformation groove 7 is arranged inside the stress relief groove 6, and the Both the stress relief groove 6 and the deformation groove 7 are arc grooves, and the diameter of the stress relief groove 6 is smaller than the diameter of the deformation groove 7 .

The two diagonal corners of the section of the metal sealing ring 2 are contact points, and the contact points are in contact with the sealing body and the sealed carrier respectively, because the hardness of the material used by the metal sealing ring 2 is higher than that of the sealing carrier. The hardness of the material used is much lower, and the metal sealing ring (2) has a special structure, so the sealing surface of the sealing carrier will not be damaged during use.

Example 3

On the basis of the above embodiments, the sealing body is a mandrel-type sealing body, and the wall thickness of the mandrel-type sealing body is designed to withstand a working pressure of 10,000 Psi, so that the external detection pressure of the metal sealing joint 5 and the internal The detection pressure can be kept consistent, and the metal sealing joint 5 is made of carbon steel, low alloy steel, 300 series stainless steel and corrosion-resistant alloy material and is seamlessly connected with the sealing body 1, so the metal sealing joint 5 can be Used in a wider range of fields, especially for hydrogen sulfide and carbon dioxide corrosion conditions, the metal sealing joint 5 can be used for low temperatures below -60°C and high temperatures above 345°C.

The outer end surface of the metal seal ring 2 forms an included angle with the contact surface of the support ring 3, and the included angle is 5°-15°, which is determined by the inconsistency of the contact angle between the support ring 3 and the metal seal ring 2 The priority configuration to reach the power point.

This kind of metal sealing structure for the end of the tubing hanger is not limited in size when used, and can be made into metal sealing ring joints of various sizes, which will not affect the quality of the seal under pressure fluctuations; metal sealing joints The main function is to provide and maintain a metal-to-metal seal. The metal seal joint can be used not only in the field of API6A, but also in other fields that require metal-to-metal sealing, and can be reused many times without replacement; It can be sealed by providing a special groove; the structure is simple, and the internal parts of the invention can be interchanged with each other, and no special tools are required for installation and disassembly, which is convenient for assembly, saves installation and debugging time, and reduces downtime to a minimum.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only includes an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (8)

1. A metal sealing structure for the end of the tubing hanger, comprising: A sealing body, the sealing body is composed of a sealing body (1) and a metal sealing joint (5), A circlip (4), half of the circlip (4) is embedded in the outer end surface of the sealing body (1), a support ring (3), and the support ring (3) is arranged on the metal sealing joint the outside of (5), A metal sealing ring (2), the metal sealing ring (2) is set in the support ring (3), It is characterized in that: the left and right sides of the metal sealing ring (2) are provided with stress relief grooves (6), and one of the stress relief grooves (6) is arranged on a side close to the metal sealing joint (5). On the left and right sides of the metal sealing ring (2), a pair of deformation grooves (7) are opened. 2. A metal sealing structure for the end of the oil pipe hanger according to claim 1, characterized in that: the metal sealing ring (2) is tubular and its cross-section is rhombus, and the metal sealing ring (2) Sealing through a rhomboid cross-section. 3. A metal sealing structure for the end of the oil pipe hanger according to claim 1, characterized in that: the stress relief groove (6) and the deformation groove (7) are both sealed with the metal sealing ring ( 2) The center of the rhombus section is set as the central symmetry point. 4. A metal sealing structure for the end of the tubing hanger according to claim 1, characterized in that: the two diagonal corners of the cross-section of the metal sealing ring (2) are contact points, and the contact points are respectively at The sealing body is in contact with the sealed carrier. 5. A metal sealing structure for the end of the tubing hanger according to claim 1, characterized in that: the deformation groove (7) is arranged inside the stress relief groove (6), and the stress relief groove (6) Both the release groove (6) and the deformation groove (7) are circular arc grooves, and the diameter of the stress relief groove (6) is smaller than the diameter of the deformation groove (7). 6. The metal sealing structure for the end of the oil pipe hanger according to claim 1, wherein the sealing body is a mandrel type sealing body. 7. A metal sealing structure for the end of the tubing hanger according to claim 1, characterized in that: the metal sealing joint (5) is made of carbon steel, low alloy steel, 300 series stainless steel and corrosion-resistant alloy materials formed and seamlessly connected with the sealing body (1). 8. A metal sealing structure for the end of the oil pipe hanger according to claim 1, characterized in that: the outer end surface of the metal sealing ring (2) and the contact surface of the support ring (3) form a clamp Angle, the included angle is 5°-15°.