Swivel bend for oil and gas exploration

Abstract

The application belongs to the field of oil and gas exploitation equipment processing and manufacturing, and particularly relates to a movable bend for oil and gas exploitation, which comprises a bend pipe part, the bend pipe part is hollowly arranged, two ends of the bend pipe part are respectively connected with a first joint part and a second joint part, the first joint part and the second joint part are used to connect another bend pipe part or a direct head, and the wall thickness of the inner arc of the bend pipe part is greater than the wall thickness of the outer arc of the bend pipe part by more than 5 mm. The wall thickness of the inner arc of the bend pipe part is greater than the wall thickness of the outer arc of the bend pipe part by more than 5 mm, so that no matter the wall thickness of the inner arc or the wall thickness of the outer arc is taken as a design reference, the scouring time of the product can be prolonged, and the overall service life is longer. Compared with the equal wall thickness design, the weight is light, the inner arc is not too thick, the processing and manufacturing are facilitated, and the cost is low.

Description

Technical Field

[0001] This application belongs to the field of oil and gas extraction equipment processing and manufacturing, specifically relating to a movable elbow used in oil and gas extraction. Background Technology

[0002] Flexible elbows are used in oil and gas extraction operations such as fracturing and cementing to connect pipelines in different spatial locations and change the direction of fluid flow.

[0003] In the process of conveying high-pressure fluids, especially fluids containing solid particles, the movable elbow needs to withstand both high pressure and the scouring of high-speed fluids. The pressure-bearing capacity and scouring resistance of the product are the key technical points of this product.

[0004] Two common problems encountered during the use of flexible elbows are: one is that the entire elbow bursts, and the other is that the pipe wall is thinned due to erosion, leading to its scrapping. Utility Model Content

[0005] Therefore, it is necessary to propose a flexible elbow that can be used in oil and gas extraction, which can ensure the safety and reliability of pressure bearing, as well as a longer service life, and is also easy to process and manufacture.

[0006] An active elbow for oil and gas extraction includes a bent pipe section, which is hollow. The two ends of the bent pipe section are respectively connected to a first connector section and a second connector section. The first connector section and the second connector section are used to connect to other bent pipe sections or direct connectors. The wall thickness of the inner arc of the bent pipe section is more than 5 mm greater than the wall thickness of the outer arc of the bent pipe section.

[0007] In some embodiments, the inner diameter of the bend is D, and the radius of curvature of the arc of the inner diameter centerline is R, wherein the relationship between the radius of curvature R and the inner diameter D is: 1.5≤R / D≤4.

[0008] In some embodiments, the value of R / D is 1, 1.5, 2.0, 2.5, 3.0, or 3.5.

[0009] In some embodiments, the surface hardness of the bend is in the range of 55 to 65 HRC.

[0010] In some embodiments, the surface of the bend has a carburized and quenched layer, a carbonitriding layer, or a surface quenched layer.

[0011] In some embodiments, the movable elbow includes two bent sections connected by a female end of the elbow, defined as a first bent section and a second bent section, and the first bent section, the female end of the elbow, and the second bent section are generally U-shaped.

[0012] In some embodiments, one end of the U-shaped structure is connected to a first direct head.

[0013] In some embodiments, the other end of the U-shaped structure is connected to a third bend, the inner arc of which faces away from the first direct head.

[0014] In some embodiments, a second straight connector is also connected to the third bend.

[0015] In some embodiments, the movable elbow further includes a third and a fourth straight connector, respectively connected to both ends of the bend.

[0016] The aforementioned movable elbow used for oil and gas extraction has an inner arc wall thickness that is more than 5mm thicker than the outer arc wall thickness. This allows the product's scouring time to be extended, resulting in a longer overall lifespan, regardless of whether the inner or outer arc wall thickness is used as a design reference. Compared to designs with equal wall thickness, it is lighter in weight, avoids excessive inner arc thickness, facilitates processing and manufacturing, and is cost-effective. Attached Figure Description

[0017] Figure 1 This is a simulation analysis diagram of the active elbow of the relevant technology.

[0018] Figure 2 This is a finite element stress analysis diagram of the active elbow of the relevant technology.

[0019] Figure 3 This is a cross-sectional structural diagram of the movable elbow in Embodiment 1 of this application.

[0020] Figure 4 This is a schematic diagram of the inner diameter of the bend and the radius of curvature of the arc of the inner diameter centerline of the movable elbow in Embodiment 1 of this application.

[0021] Figure 5 This is a schematic diagram of the structure of the movable elbow in Embodiment 2 of this application.

[0022] Figure 6 This is a schematic diagram of the structure of the movable elbow in Embodiment 3 of this application.

[0023] Figure 7 This is a schematic diagram of the structure of the movable elbow in Embodiment 4 of this application.

[0024] Figure 8 This is a schematic diagram of the structure of the movable elbow in Embodiment 5 of this application.

[0025] Figure 9 This is a schematic diagram of the structure of the movable elbow in Embodiment Six of this application.

[0026] Figure 10 This is a schematic diagram of the structure of the movable elbow in Embodiment 7 of this application.

[0027] Figure label:

[0028] 100. Flexible elbow; 10. Bend section; 101. Inner arc; 102. Outer arc; 110. First joint section; 120. Second joint section; 130. First bend section; 140. Second bend section; 150. Third bend section; 20. Elbow female end; 30. First straight connector; 40. Second straight connector; 50. Third straight connector; 60. Fourth straight connector. Detailed Implementation

[0029] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0030] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential direction" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the equipment or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0031] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0032] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0033] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0034] As described in the background section, movable elbows used in oil and gas extraction should ideally ensure both pressure-bearing safety and reliability, as well as a longer service life. Furthermore, they should also be easy to manufacture.

[0035] To ensure the product's pressure-bearing capacity meets design requirements, guarantees construction safety, and facilitates manufacturing, this application proposes an embodiment of a movable elbow 100 for oil and gas extraction. The elbow includes a hollow section 10, with the inner arc 101 of the elbow 10 having a wall thickness at least 5 mm greater than the outer arc 102. Both ends of the elbow 10 are connected to a first connector 110 and a second connector 120, respectively. The first connector 110 and the second connector 120 are used to connect with other movable elbows 100 or straight elbows via, for example, threaded engagement, thereby constructing movable elbows 100 of different specifications.

[0036] Specifically, the applicant conducted a simulation analysis of the bend section 10 of the movable elbow 100 to analyze its fatigue changes during use. Specifically, FLUENT software was used to simulate bend erosion, exploring the influence of multiphase flow on elbow erosion failure; and ANSYS software was used to analyze the flow field of the fluid medium flowing through the pipe elbow, numerically simulating the liquid-solid two-phase flow scouring process in the movable elbow 100, obtaining erosion rate contour maps and structural critical locations of the movable elbow 100, such as... Figure 1 As shown, the erosion depth at critical locations of different movable elbow 100 structures under various working conditions was analyzed. The erosion contour map shows that the erosion rate on the outer side of the elbow is 10 times that on the inner side (erosion rate in the red area > yellow area > green area > blue area). This means that in actual use, due to the erosive effect of the fluid and the centrifugal force, the wall thickness of the outer arc 102 thins faster due to fluid erosion. Therefore, to ensure the elbow's erosion time and service life, the wall thickness on the outer side of the elbow should be increased as much as possible.

[0037] In addition, such as Figure 2As shown, finite element simulation revealed that, under internal pressure, the stress on the inner arc 101 of the movable elbow 100 is significantly greater than that on the outer arc 102. Figure 2 In the diagram, the stress in the red area is greater than in other areas. Therefore, given the limited space for wall thickness design, the inner arc 101 requires a larger wall thickness.

[0038] As can be seen from the above analysis, in order to ensure both the safety and reliability of pressure bearing and a longer scouring life, the wall thickness of the inner arc 101 and the outer arc 102 can be increased as much as possible when permissible.

[0039] One possible option is to make the wall thickness of both the inner arc 101 and the outer arc 102 sufficiently large, which would ensure both pressure resistance and reliability, as well as a longer service life. However, in practice, the greater the wall thickness, the more difficult it is to manufacture. For example, the inner arc 101 is the extrusion part during the bending and forming of the movable elbow 100. If the wall thickness of the inner arc 101 is too large, it will be detrimental to its manufacturing. Furthermore, a larger wall thickness requires more material for the movable elbow 100, resulting in higher costs.

[0040] Based on the above, the applicant proposes a solution: while ensuring the wall thickness of the inner arc 101 meets strength requirements, the wall thickness of the outer arc 102 should be increased as much as possible. Specifically, when designing the wall thicknesses of the inner arc 101 and outer arc 102, to maximize the product's service life and facilitate manufacturing, an optimal wall thickness relationship needs to be established. While ensuring the wall thickness of the inner arc 101 meets strength requirements, the wall thickness of the outer arc 102 should be increased as much as possible to extend the product's scouring time and overall lifespan. Analysis shows the optimal wall thickness relationship is: inner arc 101 wall thickness - outer arc 102 wall thickness > 5mm.

[0041] Specifically, after determining the wall thickness of the inner arc 101 based on the working conditions, the maximum upper limit of the wall thickness of the outer arc 102 can be 5mm less than the wall thickness of the inner arc 101. Conversely, if the wall thickness of the outer arc 102 is determined first, then the wall thickness of the inner arc 101 should be increased by at least 5mm. This way, both the inner arc 101 and the outer arc 102 of the resulting movable elbow 100 will meet the requirements, and the smaller wall thickness of the outer arc 102 will reduce the weight of the movable elbow 100 compared to a design with equal wall thickness. It is easy to understand that the outer wall thickness of movable elbows 100 varies depending on the working conditions. In practice, the wall thickness of the outer arc 102 of commonly used movable elbows 100 is 15-20mm; or 27-33mm.

[0042] The active elbow 100 of this application has an inner arc 101 wall thickness that is more than 5mm thicker than the outer arc 102 wall thickness of the bend 10. This allows the product's flushing time to be extended, resulting in a longer overall lifespan, regardless of whether the design reference is based on the inner arc 101 wall thickness or the outer arc 102 wall thickness. Compared with a design with equal wall thickness, it is lighter in weight and avoids the inner arc 101 being too thick, thus facilitating processing and manufacturing and reducing costs.

[0043] In some embodiments, reference is made to Figure 3 and Figure 4 The inner diameter of the bend 10 is D, and the radius of curvature of the arc of the inner diameter centerline is R. The relationship between the radius of curvature R and the inner diameter D is: 1.5≤R / D≤4.

[0044] Specifically, after constructing a geometric model, meshing, and setting boundary conditions, the parameters most commonly used in engineering, such as pressure, flow rate, sand ratio, sand density, and viscosity, were set according to the erosion simulation. Through simulation calculations, it was found that the bend diameter ratio affects the erosion wear rate of the movable elbow 100, and the bend diameter ratio is also different for bends with different structures.

[0045] The bend-to-diameter ratio refers to the ratio of the radius of curvature R of the arc along the centerline of the bend to the inner diameter D of the bend, i.e., R / D. Figure 4 As shown, erosion models of high-pressure manifolds were established with R / D values ​​of 1, 1.5, 2.0, 2.5, 3.0, and 3.5. The study found that the larger the bend-to-diameter ratio, the smaller the erosion rate. However, the increased radius of curvature of the bend leads to material waste, increased processing difficulty, and affects the on-site manifold assembly connection. Therefore, the most economical bend-to-diameter ratio is: 1.5≤R / D≤4.

[0046] In some embodiments, the surface hardness of the bend 10 ranges from 55 to 65 HRC.

[0047] In actual production, the surface of the bend section 10 undergoes surface heat treatment to improve surface hardness, thereby enhancing wear resistance and fatigue strength. By setting parameters such as pressure, flow rate, sand ratio, sand density, and viscosity during actual use, simulation calculations are performed to obtain the erosion speed of the elbow under different surface hardnesses. Combining common heat treatment processes in engineering, such as carburizing and quenching, carbonitriding, and surface quenching, surface hardness can be improved, resulting in a carburized and quenched layer, a carbonitrided layer, or a surface quenched layer on the surface of the bend section 10, thereby improving wear resistance. The most economical hardness range for the surface of the bend section 10 is 55–65 HRC.

[0048] exist Figure 3 and Figure 4 Based on the existing movable elbow 100, this application further develops movable elbows 100 in different forms to adapt to different applications. These are described below with reference to the accompanying drawings.

[0049] like Figure 5 As shown in Embodiment 2 of this application, the movable elbow 100 includes two bent pipe sections 10 connected by the elbow female end 20, which are respectively defined as the first bent pipe section 130 and the second bent pipe section 140. The first bent pipe section 130, the elbow female end 20 and the second bent pipe section 140 are generally U-shaped.

[0050] like Figure 6 As shown, in Embodiment 3 of this application, with Figure 5 The difference in the embodiment shown is that, in this embodiment, one end of the U-shaped structure is connected to a first direct head 30.

[0051] like Figure 7 As shown, with Figure 5 The difference between the embodiments shown is that, in this fourth embodiment, one end of the U-shaped structure is connected to a first direct connector 30, and the other end is connected to a second direct connector 40.

[0052] like Figure 8 As shown, in Embodiment 5 of this application, with Figure 6 The difference in the embodiment shown is that, in this embodiment, one end of the U-shaped structure is connected to the first direct head 30, and the other end of the U-shaped structure is connected to the third bend section 15010, with the inner arc 101 of the third bend section 15010 facing away from the first direct head 30.

[0053] like Figure 9 As shown, in Embodiment Six of this application, in Figure 8 Based on the embodiment shown, a second direct head 40 is also connected to the third bend section 15010.

[0054] like Figure 10 As shown in Embodiment 7 of this application, the movable elbow 100 further includes a third straight head 50 and a fourth straight head 60, which are respectively connected to the two ends of the bend section 10.

[0055] like Figures 5 to 10 As shown, based on the concept of this application, different forms of movable elbows 100 can be constructed. The bent pipe portion 10 in these movable elbows 100 has a long service life and is easy to process and manufacture.

[0056] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A movable elbow for oil and gas extraction, comprising a bent pipe section, the bent pipe section being hollow, and a first connector section and a second connector section respectively connecting to both ends of the bent pipe section, the first connector section and the second connector section being used to connect to another bent pipe section or a straight connector, characterized in that, The wall thickness of the inner arc of the bend is more than 5 mm greater than the wall thickness of the outer arc of the bend.

2. The movable elbow for oil and gas extraction according to claim 1, characterized in that, The inner diameter of the bend is D, and the radius of curvature of the arc of the inner diameter centerline is R. The relationship between the radius of curvature R and the inner diameter D is: 1.5≤R / D≤4.

3. The movable elbow for oil and gas extraction according to claim 2, characterized in that, The R / D value is 1, 1.5, 2.0, 2.5, 3.0, or 3.

5.

4. The movable elbow for oil and gas extraction according to claim 1, characterized in that, The surface hardness of the bent section is in the range of 55 to 65 HRC.

5. The movable elbow for oil and gas extraction according to claim 4, characterized in that, The surface of the bent section has a carburized and quenched layer, a carbonitriding layer, or a surface quenching layer.

6. The movable elbow for oil and gas extraction according to claim 1, characterized in that, The movable elbow includes two bent pipe sections connected by the female end of the elbow, which are respectively defined as the first bent pipe section and the second bent pipe section. The first bent pipe section, the female end of the elbow, and the second bent pipe section are generally U-shaped.

7. The movable elbow for oil and gas extraction according to claim 6, characterized in that, One end of the U-shaped structure is connected to a first direct head.

8. The movable elbow for oil and gas extraction according to claim 7, characterized in that, The other end of the U-shaped structure is connected to a third bend, the inner arc of which faces away from the first direct head.

9. The movable elbow for oil and gas extraction according to claim 8, characterized in that, A second direct connector is also connected to the third bend.

10. The movable elbow for oil and gas extraction according to claim 1, characterized in that, The movable elbow also includes a third and a fourth direct connector, which are respectively connected to the two ends of the bend.

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