A design optimization method for H-type metal sealing ring in gas wellhead device

Abstract

The present invention proposes a design optimization method for an H-type metal sealing ring in a gas wellhead device. The method uses 3D software for geometric modeling and Workbench software for simulation analysis to simulate the situation of the metal sealing ring under a preload of 2mm. The analysis results show that the designed H-type metal sealing ring has higher sealing performance than the O-type metal sealing ring. However, based on the internal deformation and stress distribution of the H-type metal sealing ring, the stress distribution of the H-type metal sealing ring is concentrated in the middle connecting section, the deformation is larger at the upper and lower teeth, and the stress and deformation are larger at the middle teeth. Finally, these three parts are further structurally optimized. Finally, appropriate structural parameters are selected to optimize the internal deformation and stress distribution of the H-type metal sealing ring. The optimized H-type metal sealing ring in the present invention has higher sealing performance; the maximum stress and maximum stress area it is subjected to are much smaller than those of the existing O-type metal sealing ring.

Description

Technical Field

[0001] The invention belongs to the technical field of throttle valve erosion, and in particular relates to a design optimization method for an H-shaped metal sealing ring in a gas production wellhead device. Background Art

[0002] A gas wellhead assembly is a pressure-bearing device used to control wellhead pressure and gas flow at the natural gas wellhead. It can also be used for various operations such as acid fracturing, water injection, and testing. It primarily consists of a casing head, a tubing head, and a Christmas tree. With the development of the petrochemical industry, gas wellhead pressures are increasing, placing increasing pressure requirements on wellhead assembly. The reliability and controllability of oil and gas wellhead assembly and valves have become primary concerns for wellhead assembly, and the sealing performance of the equipment is one of the most critical performance characteristics.

[0003] The O-ring used in the hanger of the existing gas wellhead device has many shortcomings: 1. The sealing performance is poor, and it is easy to roll and twist, causing damage; 2. The internal force and deformation are large.

[0004] Therefore, how to improve the sealing performance of the sealing ring and reduce the maximum stress of the sealing ring is a technical problem that needs to be solved urgently in the existing technology. Summary of the Invention

[0005] The purpose of the present invention is to provide a design optimization method for an H-type metal sealing ring in a gas wellhead device. The optimized H-type metal sealing ring has higher sealing performance; the maximum stress and maximum stress area it is subjected to are much smaller than those of the existing O-type metal sealing ring.

[0006] A design optimization method for an H-shaped metal sealing ring in a gas wellhead device comprises the following steps:

[0007] S1: Design the structural parameters of the H-type metal sealing ring according to the basic parameters of the hanger in the gas wellhead device;

[0008] S2: Based on the structural parameters obtained in step S1, a simplified model is established for the simulation, and material properties and meshing are set for the simplified model in ANSYS Workbench:

[0009] Among them, one simplified model retains the hanger wall, H-type metal sealing ring and gas wellhead device wall. The other simplified model retains the hanger wall, O-type metal sealing ring and gas wellhead device wall.

[0010] S3: Import the two simplified models in step S2 into WorkbenchFluent software respectively, and perform deformation and stress simulation analysis on the two simplified models based on the Gaussian flux model;

[0011] S4: Import the H-type metal sealing ring model in step S2 into WorkbenchFluent software, and perform deformation stress simulation analysis on the H-type metal sealing ring by changing one parameter among the middle connecting section, the middle tooth length, and the left and right tooth widths each time based on the Gaussian flux model;

[0012] S5: According to the deformation stress simulation analysis results in step S4, the middle connecting section, left and right widths, and middle tooth length of the H-shaped metal sealing ring are selected.

[0013] Preferably, the Gaussian flux model formula in step S3 is:

[0014]

[0015] Where, The positive side is the outside;

[0016] dy、d z d X for Direction cosines of the external normal vector;

[0017] is the first-order partial derivative of the function in P, Q, and R on Ω.

[0018] Preferably, the stress-strain formula in step S3 is:

[0019] ε true =ln(1+ε nom );

[0020] σ true =ln(1+σ nom );

[0021] Where: ε true - material true strain;

[0022] ε nom - Material nominal strain;

[0023] σ true - material true stress;

[0024] σ nom -Material nominal stress.

[0025] Preferably, the deformation stress simulation analysis results include deformation amount, stress distribution and maximum deformation area.

[0026] Compared with the prior art, the advantages of the present invention are as follows: based on the existing O-type metal sealing ring in the gas wellhead device, a new type of H-type metal sealing ring is designed, geometric modeling is performed using 3D software, and simulation analysis is performed using Workbench software to simulate the situation of the metal sealing ring under a preload of 2mm. The analysis results show that the designed H-type metal sealing ring has higher sealing performance than the O-type metal sealing ring, but based on the internal deformation and stress distribution of the H-type metal sealing ring, the stress distribution of the H-type metal sealing ring is concentrated in the middle connection section, the deformation is larger at the upper and lower teeth, and the stress and deformation are larger at the middle teeth. Next, these three parts are further structurally optimized. Finally, the H-type metal sealing ring with the structural parameters of a 30° arc in the middle connection section, a 0.5mm length in the middle teeth, and a 2mm width on both sides is selected to have the best internal deformation and stress distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the location diagram of the seal ring of the hanger of the gas wellhead device;

[0028] Figure 2 It is a three-dimensional model of the H-type metal sealing ring;

[0029] Figure 3 Plane parameter diagram of H-type metal sealing ring

[0030] Figure 4 This is a simplified simulation diagram of an H-type metal sealing ring;

[0031] Figure 5 The internal deformation of O-type metal sealing ring and H-type metal sealing ring;

[0032] Figure 6 The internal stress of O-type metal sealing ring and H-type metal sealing ring;

[0033] Figure 7 The deformation inside the H-type metal sealing ring with a middle connection arc of 20°-60°;

[0034] Figure 8 The stress inside the H-type metal sealing ring with a middle connection arc of 20°-60°;

[0035] Figure 9 The deformation inside the H-type metal sealing ring with left and right tooth width of 1mm-4mm;

[0036] Figure 10 The stress inside the H-type metal sealing ring with left and right tooth width of 1mm-4mm;

[0037] Figure 11 The internal deformation of the H-type metal sealing ring with a middle tooth length of 0.5mm-1mm;

[0038] Figure 12 The stress inside the H-type metal sealing ring with a middle tooth length of 0.5mm-1mm;

[0039] Figure 13 The deformation inside the H-type metal sealing ring with a middle connection arc of 20°-60°;

[0040] Figure 14 The stress inside the H-type metal sealing ring with a middle connection arc of 20°-60°;

[0041] Figure 15 The deformation inside the H-type metal sealing ring with left and right tooth width of 1mm-4mm;

[0042] Figure 16 The stress inside the H-type metal sealing ring with left and right tooth width of 1mm-4mm;

[0043] Figure 17 The internal deformation of the H-type metal sealing ring with a middle tooth length of 0.5mm-1mm;

[0044] Figure 18 The stress inside the H-type metal sealing ring with a middle tooth length of 0.5mm-1mm. DETAILED DESCRIPTION

[0045] The present invention will be described in more detail below with reference to schematic diagrams, which illustrate preferred embodiments of the present invention. It should be understood that those skilled in the art may modify the present invention as described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as a general guide for those skilled in the art and not as a limitation of the present invention.

[0046] The present invention provides a new design optimization method for H-type metal sealing ring, based on the hanger in the gas wellhead device such as Figure 1 Existing O-type metal sealing ring, design a new type of H-type metal sealing ring such as Figure 2 , including tooth width position 1, middle connecting section 2 and middle tooth 3.

[0047] 3D software was used for geometric modeling, and Workbench software was used for simulation analysis to simulate the situation of the metal sealing ring under a preload of 2mm. The analysis results show that the designed H-type metal sealing ring has higher sealing performance than the O-type metal sealing ring. However, based on the internal deformation and stress distribution of the H-type metal sealing ring, the stress distribution of the H-type metal sealing ring is concentrated in the middle connection section, the deformation is larger at the upper and lower teeth, and the stress and deformation are larger at the middle teeth. Next, these three parts will be further structurally optimized.

[0048] Finally, the H-shaped metal sealing ring with the best internal deformation and stress distribution was selected, with the structural parameters of the middle connection section arc of 30°, the middle tooth length of 0.5mm, and the left and right width of 2mm.

[0049] Design optimization method of H-type metal sealing ring in the gas wellhead device:

[0050] S1: Design the structural parameters of the H-type metal sealing ring according to the basic parameters of the hanger in the gas wellhead device. Figure 3 The height is 20mm, the length is 15mm, and the extra distance of 0.8mm is used for pre-tightening. The middle connecting section is 5mm, the angle between the middle section and the left and right teeth is 113°, and the left and right tooth width is 1mm.

[0051] S2: Based on the structural parameters obtained in step S1, a simplified model required for simulation is established in Solidworks, and material properties are set and meshing is performed for the simplified model in ANSYS Workbench.

[0052] One simplified model retains the hanger wall, H-shaped metal seal ring, and gas wellhead device wall, while the other simplified model retains the hanger wall, O-shaped metal seal ring, and gas wellhead device wall.

[0053] The H-shaped metal seal serves as the primary seal between the hanger and the tree. Its technical parameters and requirements are as follows: a rated maximum working pressure of 140 MPa; API specification grade PSL3; and performance test PR2. Considering these requirements, alloy steel 8630 was selected for the H-shaped metal seal ring, as well as for the tubing hanger and tree body. All other settings were left as default.

[0054] S3: The two simplified models in step S2 are imported into WorkbenchFluent software respectively, and deformation stress simulation analysis is performed on the two simplified models based on the Gaussian flux model.

[0055] The deformation stress simulation analysis results include deformation, stress distribution and maximum deformation area.

[0056] Specifically, for the internal deformation of O-type metal sealing rings and H-type metal sealing rings, Figure 5 The maximum deformation of the O-type metal sealing ring is located in the upper left corner of the circle, and the maximum deformation is 0.295mm; the maximum deformation of the H-type metal sealing ring is located at the contact position between the upper right tooth and the sealing surface of the gas wellhead device, and the maximum deformation is 0.2467mm; the maximum deformation areas of the two are basically the same, but the maximum deformation of the H-type metal sealing ring is significantly smaller than that of the O-type metal sealing ring.

[0057] The internal stress distribution of O-type metal sealing ring and H-type metal sealing ring is as follows Figure 6 The maximum stress of the O-type metal sealing ring is in the middle section of the circle, with a maximum stress of 193Mpa; the maximum stress of the H-type metal sealing ring is in the middle connecting section and the upper and lower ends of the right tooth, with a maximum stress of 131Mpa; from the simulation diagram, it can be clearly seen that the maximum stress distribution area and the maximum stress of the O-type metal sealing ring are much greater than those of the H-type metal sealing ring.

[0058] Whether it is deformation, maximum stress distribution area, or maximum stress, the H-type metal sealing ring is superior to the O-type metal sealing ring. Therefore, the designed H-type metal sealing ring has higher sealing performance than the O-type metal sealing ring. However, according to the internal deformation and stress distribution of the H-type metal sealing ring (the stress distribution is concentrated in the middle connection section, the deformation is larger at the upper and lower teeth, and the stress and deformation are larger at the middle teeth), it still needs to be optimized.

[0059] Gaussian flux model formula in steps S3 and S4:

[0060]

[0061] Where, The positive side is the outside;

[0062] dy、d z d X for Direction cosines of the external normal vector;

[0063] is the first-order partial derivative of the function in P, Q, and R on Ω.

[0064] The stress-strain formula in steps S3 and S4 is:

[0065] ε true =ln(1+ε nom ).

[0066] σ true =ln(1+σ nom ).

[0067] Where: ε true - material true strain;

[0068] ε nom - Material nominal strain;

[0069] σ true - material true stress;

[0070] σ nom -Material nominal stress.

[0071] S4: The simplified model of the H-type metal sealing ring in step S2 is imported into the WorkbenchFluent software. Based on the Gaussian flux model, the deformation stress simulation analysis of the H-type metal sealing ring is performed by changing one parameter of the middle connecting section, the middle tooth length, and the left and right tooth widths each time.

[0072] Specifically, the middle connecting section, middle tooth length, and left and right tooth widths of the H-type metal sealing ring are further optimized based on the maximum variable and stress distribution.

[0073] (1) The influence of different intermediate connection section curvatures on the deformation and stress distribution of H-type metal sealing rings.

[0074] Deformation distribution as Figure 7 、 Figure 13 When the model can be modeled, 20°-60° is selected as a stage with every 5° for model analysis. It is obvious that the smallest deformation variable is when the arc of the middle connecting section is 20°, and its maximum deformation variable is 0.11mm. Although the deformation variable is reduced compared with that before optimization, the maximum deformation area is more than twice the original; the smallest maximum deformation area is when the arc of the middle connecting section is 50°. Its maximum deformation area is reduced by 1 / 2 compared with before, but its maximum deformation variable becomes 0.58mm.

[0075] Stress distribution as Figure 8 、 Figure 14 The smallest maximum stress value is when the arc of the middle connection section is 35°, and its maximum stress is 128Mpa. The maximum stress value is when the arc of the middle connection section is 20°, and its maximum stress is 140Mpa. There is a difference of about 10Mpa in the maximum stress values ​​before and after optimization.

[0076] Considering the maximum deformation, maximum deformation area and maximum stress, when the arc of the middle connecting section is selected as 30°, its maximum deformation is 0.16 mm, which is much smaller than the unoptimized H-type metal sealing ring (the H-type metal sealing ring in step S3). Its maximum deformation area is slightly smaller than the unoptimized H-type metal sealing ring, and the maximum stress is 131.7 MPa, which is basically the same as before optimization.

[0077] (2) The influence of different left and right widths on the deformation and stress distribution of H-type metal sealing ring.

[0078] Deformation distribution as Figure 9 、 Figure 15When the model can be modeled, 1mm-4mm is selected as a stage with every 1mm for model analysis. It is obvious that the smallest deformation variable is when the left and right width is 3mm, and its maximum deformation variable is 0.147mm, but its maximum deformation area is more than 1 times of the original; the smallest maximum deformation area is when the left and right width is 4mm, and the maximum deformation area is more than 1 times smaller than the original, but its maximum deformation variable is 0.705mm.

[0079] Stress distribution as Figure 10 、 Figure 16 The smallest maximum stress value is when the left and right width is 2mm, the maximum stress is 130Mpa, and the maximum stress is when the left and right width is 3mm, the maximum stress is 140Mpa; there is a difference of about 10Mpa in the maximum stress values ​​before and after optimization.

[0080] Considering the maximum deformation, maximum deformation area and maximum stress, when the left and right widths are 2mm, the maximum deformation is 0.22mm, slightly smaller than the unoptimized H-type metal sealing ring. The maximum deformation area is basically the same as that of the unoptimized H-type metal sealing ring, and the maximum stress is 130Mpa, slightly smaller than the unoptimized H-type metal sealing ring.

[0081] (3) Effect of different middle tooth lengths on the deformation and stress distribution of H-type metal sealing rings

[0082] Deformation distribution as Figure 11 、 Figure 17 When the model can be built, 0.5mm-1mm is selected as a stage with every 0.1mm for simulation analysis. It is obvious that the smallest deformation variable is when the middle tooth length is 0.5mm, and the maximum deformation variable is 0.107mm; the smallest maximum deformation area is when the middle tooth length is 0.5mm, and the deformation is basically uniform.

[0083] Stress distribution as Figure 12 、 Figure 18 The smallest maximum stress value is when the middle tooth length is 0.5mm, and its maximum stress is 86.7Mpa. The maximum stress value is when the middle tooth length is 1mm, and its maximum stress is 131Mpa. There is a difference of about 45Mpa in the maximum stress values ​​before and after optimization.

[0084] Considering the maximum deformation, maximum deformation area and maximum stress, when the middle tooth length is 0.5mm, its maximum deformation is 0.107mm, which is much smaller than the unoptimized H-type metal sealing ring. Its maximum deformation area is much smaller than the unoptimized H-type metal sealing ring. The maximum stress is 86.7Mpa, which is also much smaller than the unoptimized H-type metal sealing ring.

[0085] S5: According to the deformation stress simulation analysis results in step S4, the middle connecting section, left and right widths, and middle tooth length of the H-shaped metal sealing ring are selected.

[0086] Finally, the H-shaped metal sealing ring with the best internal deformation and stress distribution was selected, with the structural parameters of the middle connection section arc of 30°, the middle tooth length of 0.5mm, and the left and right width of 2mm.

[0087] The above description is merely a preferred embodiment of the present invention and does not limit the present invention in any way. Any person skilled in the art who, without departing from the scope of the present invention, makes any equivalent substitution, modification, or other changes to the technical solution and technical content disclosed in the present invention shall be deemed to be within the scope of the present invention and still fall within the scope of protection of the present invention.

Claims

1. A design optimization method for an H-type metal sealing ring in a gas wellhead device, characterized in that: The following steps are involved: S1: Design the structural parameters of the H-type metal sealing ring according to the basic parameters of the hanger in the gas wellhead device; S2: Based on the structural parameters obtained in step S1, a simplified model is established for the simulation. Material properties are set and meshing is performed for the simplified model in ANSYS Workbench: Among them, one simplified model retains the hanger wall, H-type metal sealing ring and gas wellhead device wall; the other simplified model retains the hanger wall, O-type metal sealing ring and gas wellhead device wall; S3: Import the two simplified models in step S2 into WorkbenchFluent software respectively, and perform deformation and stress simulation analysis on the two simplified models based on the Gaussian flux model; S4: Import the H-type metal sealing ring model in step S2 into WorkbenchFluent software, and perform deformation stress simulation analysis on the H-type metal sealing ring by changing one parameter among the middle connecting section, the middle tooth length, and the left and right tooth widths each time based on the Gaussian flux model; S5: According to the deformation stress simulation analysis results in step S4, the middle connecting section, left and right widths, and middle tooth length of the H-shaped metal sealing ring are selected; Gaussian flux model formula in step S3: Where, The positive side is the outside; dy、d z d X for Direction cosines of the external normal vector; is the first-order partial derivative of the functions P, Q, and R on Ω; The stress-strain formula in step S3 is: e true =ln(1+ε nom ); s true =ln(1+σ nom ); Where: ε true - material true strain; ε nom - Material nominal strain; σ true - material true stress; σ nom -Material nominal stress.

2. The design optimization method of the H-type metal sealing ring in the gas wellhead device according to claim 1 is characterized in that: The deformation stress simulation analysis results include deformation, stress distribution and maximum deformation area.

Images