Tubular threaded joint

Abstract

The invention relates to a threaded joint (1) having a longitudinal axis (x), said joint comprising a first tubular component (C1) and a second tubular component (C2) screwed together, a first axial length BSL between a female inner abutment surface (23) and a female outer abutment surface (21) being greater than a second axial length PSL between a male inner abutment surface (13) and a male outer abutment surface (11), the first axial length BSL and the second axial length PSL being such that a gap (30) is formed between the male outer abutment surface (11) and the female outer abutment surface (21), said gap (30) being closable by contact between the male outer abutment surface (11) and the female outer abutment surface (21) when an axial compressive load is applied.

Description

Description Title of the invention: Tubular threaded joint technical field [1]The invention relates to the field of tubular threaded joints. More particularly, the invention relates to metallic tubular threaded joints used in the oil and gas, energy or storage industry, and especially for uses such as hydrocarbon well operation, hydrocarbon transport, carbon capture or geothermal energy. Technological background [2] The term "threaded joint" herein means an assembly consisting of substantially tubular, metallic components joined together by screwing. The tubular components may be tubes or any type of connecting piece commonly used in the field of the invention, such as sleeves. Such metallic tubular components preferably have a yield strength greater than or equal to 450 MPa. [3]Each tubular component has an end portion with a male or female threaded area for screwing into a corresponding end portion of a similar component. When assembled in this way, the threaded tubular components form what is called a joint or connection. [4] These joints are subjected to a wide variety of tensile or axial compressive stresses, internal or external fluid pressure, bending or torsion, possibly combined, and of fluctuating intensity. Sealing must be ensured despite these stresses and despite harsh operating conditions on site. [5]In recent years, the demand from operators in the field of the invention has evolved. Thus, there is an increasing demand from operators for threaded joints to exhibit better resistance to all these stresses, particularly when the load of the stress applied to the joint exceeds the elastic limit of said joint. [6] To meet this requirement, the prior art described in patent EP3572612 is a tubular threaded joint comprising a tubular female end extending from a main body of a first tubular element, and a tubular male end extending from a main body of a second tubular element. This joint has two stepped threaded portions, between which a first stop is disposed. The joint further comprises a second stop formed by a male free end and a female internal shoulder. The threads of the tubular components forming this joint have bearing flanks and engagement flanks with exactly the same pitch. The disadvantage of such a joint is that axial play remains at the bearing flanks and / or the engagement flanks of the thread. When such a joint is subjected to high mechanical stresses, there is a high risk that this axial play will cause leakage.Due to this axial play, the grease added during coupling, particularly to limit the risk of leakage, is stored in the gaps formed between the bearing and engagement flanges. Thus, when such a joint transitions from a first state of tensile stress to a second state of compressive stress, the gaps that were open in the first state of stress close, thereby opening new gaps between the thread flanges that were in contact in the first state of stress but are no longer in the second. This transition from one state of stress to another results in a movement of grease from the gaps that were open in the joint's first state of stress to the gaps that are formed when the joint transitions to the second state of stress.With this movement of grease within the threads, the bearing and engagement flanks alternately move apart and then come into direct contact, and vice versa, depending on the stress state of the seal. The fact that the thread flanks regularly come into direct contact significantly increases the risk of seizing, which drastically reduces the seal's lifespan. Consequently, such seals must be replaced frequently, complicating maintenance for operators and generating additional operating costs. Summary [7] In order to overcome the above drawbacks, a first objective of the invention is to significantly reduce the risk of seizing at the level of a threaded joint while improving the resistance of the threaded joint to mechanical stresses. In addition, a second objective of the invention is to reduce the operational costs generated by the use of the threaded joint while simplifying on-site operations. [8]Thus, the invention provides a threaded joint having a longitudinal axis x, said joint comprising a first tubular component and a second tubular component, the first tubular component and the second tubular component being screwed together, the first component comprising a first tube and a male element disposed at one end of said first tube, the male element comprising successively from the first tube to an internal male stop surface of said male element: an external male stop surface, at least a first male threaded portion having a self-locking variable-width thread profile, and the internal male stop surface, the second component comprising a second tube and a female element disposed at one end of said second tube, the female element comprising successively from the second tube to an external female stop surface of said female element: an internal female stop surface,at least one first female threaded portion having a variable-width, self-locking thread profile, a female lip, and the female external abutment surface, a first axial length BSL between the female internal abutment surface and the female external abutment surface being greater than a second axial length PSL between the male internal abutment surface and the male external abutment surface, the first axial length BSL and the second axial length PSL being such that a gap is formed between the male external abutment surface and the female external abutment surface, said gap being capable of being closed by contact between the male external abutment surface and the female external abutment surface when an axial compressive load is applied. [9] The gap formed between the male external thrust surface and the female external thrust surface helps to reduce the compressive stress exerted on the thread flanks when the applied compressive load exceeds the joint's elastic limit. Thus, when the tubular components are screwed together and an axial compressive load is applied, the thrust surface The male external thread and the female external thrust surface come into contact as soon as the axial compressive load exceeds the thread's yield strength. This results in the compressive load being immediately distributed, on the one hand, onto the thread flanks, and on the other hand, onto the male and female external thrust surfaces. This load distribution maintains the thread's sealing function. This male and female element configuration thus produces a seal with improved compression performance, particularly beyond its yield strength.

[0010] The internal diameter of a joint decreases axially from the outer bearing surfaces to the inner bearing surfaces. Therefore, the surface area of ​​an outer bearing surface is necessarily larger than the surface area of ​​an intermediate bearing surface, and an intermediate bearing surface is necessarily larger than an inner bearing surface. Consequently, the fact that the bearing contact occurs between the outer bearing surfaces allows for a larger bearing contact area and thus a greater torque capacity than that of a joint whose bearing contact occurs at an inner or intermediate shoulder. In other words, the fact that the bearing contact occurs between the outer bearing surfaces allows for greater axial compressive loads compared to bearing contact at an inner or intermediate shoulder. [1 l] Variable-width, self-locking threads such as those used in the invention prevent a gap from forming in the thread of the seal. Thus, when the first tubular component and the second tubular component are screwed together and no axial compressive load is applied, the integrity, and in particular the sealing, of the seal is entirely produced by the torque generated by the contact between, on the one hand, the bearing flanges and the thread engagement flanges of the first tubular component, and on the other hand, the bearing flanges and the thread engagement flanges of the second tubular component. Consequently, with such a seal, it is not necessary to use grease to achieve sealing, which reduces the amount of grease used and therefore lowers operating costs.On the other hand, due to the absence of axial play between the threads, there is a risk of seizing during a change in stress state, for example during a transition from one state to another. When under tension in a state of compression, the risk of seizing is virtually zero and the lifespan of such a seal is therefore significantly increased.

[0012] According to one embodiment, the male element comprises an external male housing extending from the external male stop surface to the male threaded portion.

[0013] In one embodiment, the male external stop surface has an inclination of angle α with respect to a first axis y, said first axis y being perpendicular to the longitudinal axis x, and the female external stop surface has an inclination of angle P with respect to a second axis y”, said second axis y”, being perpendicular to the longitudinal axis x, the angles α and P being such that the male external stop surface and the female external stop surface are substantially parallel. In other words, the angles α and P are substantially equal.

[0014] Thanks to these characteristics, regardless of the value of angles a and P, the male external stop surface and the female external stop surface are always face-to-face, so as to present a maximum contact area between them, which improves the performance of the joint in compression.

[0015] For the sake of clarity, it is specified here that, in this application, any value given to angle a corresponds to an angle value measured in the trigonometric direction between the male external stop surface and the y-axis. Similarly, any value given to angle P corresponds to an angle value measured in the trigonometric direction between the female external stop surface and the y-axis.

[0016] In one embodiment, the y-axis and the male external stop surface are coaxial, and the y-axis and the female external stop surface are coaxial. The angles α and β thus formed are either zero angles or straight angles. A zero angle is defined as having a value of 0°, and a straight angle is defined as having a value of 180°.

[0017] According to one embodiment, angles a and P both have either a value of 0° or a value of 180°.

[0018] According to one embodiment, the angles a and P are such that: 0° < a < 30° and 0° <p<30°. Au-delà de 30°, lorsqu’une charge compressive axiale est appliquée au joint, la lèvre peut commencer à fléchir, ce qui risque de mener à la rupture de la lèvre.

[0019] According to one embodiment, the angles a and P are such that: 0° < a < 10° and 0° <p<io°.

[0020] According to one embodiment, the angles a and are such that: 0° < a < 5° and 0° <P<5°.

[0021] When a seal is subjected to an axial compressive load, particularly when this load exceeds the seal's elastic limit, the end of the female element tends to experience a mechanical force directed radially outwards from the tube. This phenomenon tends to reduce the contact area between the male and female external bearing surfaces, thereby decreasing the seal's compressive performance. Specific values ​​for the inclination angles of the male and female external bearing surfaces allow the force to be directed radially towards the inside of the tube, thus preventing this phenomenon.

[0022] According to one embodiment, the gap has an axial length between 0.10 mm and 1.75 mm. Preferably, the gap has an axial length between 0.10 mm and 0.82 mm, and even more preferably between 0.10 mm and 0.63 mm. Ideally, the gap has an axial length between 0.10 mm and 0.50 mm. This allows the gap to close and thus leads to an optimal improvement in compressive strength according to the compression capacities relevant to the field of the invention.

[0023] Preferably, the gap has an axial length such that: BSL x(0.5%) / 4 <interstice (30)<BSL *0,7% où BSL est en mm. The minimum value makes it possible to reduce the compressive force exerted on the sides of the threads when the load which is applied in compression exceeds the elastic limit of the joint from 25% of the compression capacity of the joint according to the invention. The maximum value makes it possible to reduce the compressive force exerted on the sides of the threads when the load which is applied in compression reaches 100% of the compression capacity of the joint according to the invention. Definitions

[0024] In this application, the term "screwed state" means that the tubular components are connected to each other in such a way as to form a joint suitable for use within the field of the invention. For example, one can cite sealing as a property necessary for the use of the seal in a field of the invention.

[0025] The term "axial length" refers to a length that extends and is measured along the longitudinal x-axis.

[0026] For clarity, a method for measuring the first BSL axial length and the second BSL axial length is presented here. The first BSL axial length can be measured from a first female internal radial end to a second female internal radial end. The distance between points projected radially onto the x-axis is thus taken. Similarly, the second PSL axial length can be measured from a first male internal radial end to a second male internal radial end. The distance between points projected radially onto the x-axis is also taken.

[0027] The term "self-locking thread" refers to a thread in which the male thread has a width that increases axially in one direction, and the female thread has a width that increases axially in a second direction, the second direction being opposite to the first. The width of self-locking threads, such as those used in the invention, can vary axially, that is, along the longitudinal axis x, and / or radially, that is, along an axis perpendicular to the longitudinal axis x. When the thread width varies radially, the threads have a dovetail profile.

[0028] Note that for the so-called "wedge" thread, the threaded portions are offered with a different pitch value for the bearing side and for the engagement side, so that the helix of this type of thread offers a tooth width which increases as the helix turns, from one end to the other, with the defined hollows between the turns of this helix decreasing according to the same progression.

[0029] It should be noted that within the framework of the invention, a stop surface is capable of being in contact with the stop but is not necessarily so once the seal is in the screwed state. Brief description of the figures

[0030] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent from the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation, with reference to the accompanying drawings.

[0031] It should be understood, however, that the present application is not limited to the specific arrangements, structures, features, embodiments, and appearance indicated. The drawings are not drawn to scale and are not intended to limit the scope of the claims to the embodiment(s) depicted in those drawings.

[0032] Therefore, it must be understood that when features mentioned in the claims are followed by references, such references are included solely to enhance understanding of the claims and do not in any way limit their scope. [fig. 1] Figure 1 is a diagram of a longitudinal sectional view of a threaded joint whose two tubular components are screwed together, according to an embodiment of the invention (thread not shown). [fig. 2] Figure 2 is a diagram of a close-up view of detail A of the threaded joint according to the invention of figure 1 (thread not shown). [fig. 3] Figure 3 is a diagram of a close-up view of a variant of detail A of a threaded joint according to an embodiment of the invention (thread not shown). Description of the implementation methods

[0033] Figure 1 illustrates a longitudinal cross-sectional view of a threaded joint 1 comprising a first tubular component Cl and a second tubular component C2 screwed together, according to an embodiment of the invention.

[0034] The first tubular component Cl comprises a first tube 10 and a male element 15. The male element 15 is disposed at one end of the first tube 10. The male element 15 is directly adjacent to the first tube 10. The male element 15 extends axially from an external male abutment surface 11 to an internal male abutment surface 13. The male element 15 comprises successively, from the external male abutment surface 11: an external male housing 14, a male threaded portion 12 having a variable-width, self-locking thread profile (not shown), and the internal male abutment surface 13. Although the thread is not described in detail in this patent application, those skilled in the art may refer to patent EP2999841, which describes a self-locking thread suitable for use in any embodiment of the present invention.

[0035] The male external stop surface 11 extends radially between a first male external radial end 16 and a first male internal radial end 18. The first male internal radial end 18 may be a fillet having a radius of curvature between 0.1 mm and 5.0 mm and connecting the male external stop surface 11 and the male external housing 14.

[0036] The male internal stop surface 13 extends radially between a second male external radial end 17 and a second male internal radial end 19. The second male external radial end 17 and the second male internal radial end 19 can be edge breaks or rounded edges, each having a respective radius of curvature and each being directly adjacent to the male internal stop surface 13.

[0037] The external male housing 14 extends from the first internal radial male end 18 to the beginning of the male threaded portion 12. The external male housing 14 has an unthreaded surface that may be cylindrical or frustoconical in shape. In Figure 1, the external male housing 14 has a cylindrical unthreaded surface that forms a right angle with the external male abutment surface 11; in other words, the unthreaded surface of the external male housing 14 and the external male abutment surface 11 are orthogonal.

[0038] The male threaded portion 12 is tapered, for example with a half-angle of taper between 0.5° and 5°, preferably between 1° and 3°. The male threaded portion 12 is located on the outside of the male element and extends from the external male housing 14 to the second external radial male end 17. The thread (not shown) of the threaded portion 12 has a variable-width, self-locking thread profile, such as a thread of type "Wedge" in English.

[0039] The second tubular component C2 comprises a second tube 20 and a female element 25. The female element 25 is disposed at one end of the second tube 20. The female element 25 is directly adjacent to the second tube 20. The female element 25 extends axially from an external female abutment surface 21 to an internal female abutment surface 23. The female element 25 comprises, successively from the external female abutment surface 21: a female lip 24, a threaded portion 12 having a thread profile with variable width with self-locking clamping (not shown), an internal female housing 28, and the internal female stop surface 23.

[0040] The female external stop surface 21 and the male external stop surface 11 are arranged opposite each other so as to delimit between them a gap 30. In figure 1, the gap 30 has an axial length of 0.43 mm.

[0041] The external female stop surface 21 extends radially between a first external female radial end 29 and a first internal female radial end 26. The first internal female radial end 26 may be an edge break or a rounding having a radius of curvature between 0.1 mm and 5.0 mm and being directly adjacent to the external female stop surface 21.

[0042] The female internal stop surface 23 is positioned opposite and at a distance from the male internal stop surface 13, for example, at an axial distance of between 2 mm and 15 mm. The female internal stop surface 23 extends from a second female internal radial end 27 to the female internal housing 28. The female internal stop surface 23 may be straight or rounded to form a fillet. In Figure 1, the female internal stop surface 23 forms a fillet with a radius of curvature whose value may, for example, be between 0.2 mm and 6.0 mm, preferably between 0.5 mm and 1.5 mm.

[0043] The female lip 24 has an internal surface 31 facing the external male housing 14. The internal surface 31 is unthreaded and cylindrical in shape. The internal surface 31 extends from the first internal radial female end 26 to a distal thread flank 32 of the female threaded portion 22.

[0044] The female threaded portion 22 has a taper substantially equal to that of the male threaded portion 12. The female threaded portion 22 is located on the inside of the female element 25 and extends from the internal female housing 28 to the distal thread flank 32. The thread (not shown) of the threaded portion 22 has a variable width self-locking thread profile, such as a "wedge" type thread.

[0045] The internal female housing 28 is directly adjacent to the fillet formed by the internal female stop surface 27 and extends to the female threaded portion 22. The internal female housing 28 has an unthreaded surface which may be cylindrical or frustoconical in shape. In Figure 1, the internal female housing 28 has a cylindrical unthreaded surface.

[0046] The first axial length BSL extends and is measured axially between the first internal female radial end 26 and the second internal female radial end 27; the distance is therefore taken between the points projected radially onto the x-axis. The first axial length BSL can be between 60 mm and 300 mm, preferably between 100 mm and 250 mm, and even more preferably between 110 mm and 225 mm. In Figure 1, the first axial length BSL is 217 mm.

[0047] A second axial length (PSL) extends and is measured axially between the first male internal radial end 18 and the second male internal radial end 19; the distance between the points projected radially onto the x-axis is therefore taken. The first axial length (PSL) can be between 60 mm and 300 mm, preferably between 100 mm and 250 mm, and even more preferably between 110 mm and 225 mm. In Figure 1, the second axial length (PSL) is 208 mm.

[0048] Figure 2 illustrates a close-up view of detail A of the threaded joint shown schematically in figure 1.

[0049] The gap 30 is delimited by the male external stop surface 11 and the female external stop surface 21. The male external stop surface 11 and the female external stop surface 21 are parallel. According to the embodiment illustrated in Figure 2, which corresponds to that of Figure 1, the male external stop surface 11 and the female external stop surface 21 are orthogonal to the longitudinal axis x of the threaded joint 1. In other words, according to this embodiment, the male external stop surface 11 forms an angle α with the y-axis, which is a straight angle or zero angle. Similarly, the female external stop surface 21 forms an angle P with the y-axis, which is a straight angle or zero angle. Both the y and y-axes are orthogonal to the longitudinal axis x. The gap 30 thus formed between the male external stop surface 11 and the female external stop surface 21 has an axial length which can be between 0.10 mm and 1.75 mm.In the embodiment illustrated in Figure 2, the gap 30 has an axial length of 0.43 mm.

[0050] Figure 3 illustrates a close-up view of a variant of detail A shown schematically in Figure 2. According to this variant, the male external stop surface 11 is inclined at an angle α with respect to the y-axis, and the female external stop surface 21 is inclined at an angle P with respect to the y-axis. Both the y and y-axes are orthogonal to the longitudinal x-axis. The angle α can have a value between 0.1° and 30°, preferably between 0.1° and 10°, and even more preferably between 0.1° and 5°. The angle P can have a value between 0.1° and 30°, preferably between 0.1° and 10°, and even more preferably between 0.1° and 5°. In the embodiment of Figure 3, both angle α and angle P have a value of 15°. The gap 30 thus formed between the male external stop surface 11 and the female external stop surface 21 has an axial length which can be between 0.10 mm and 1.75 mm.In the embodiment illustrated in Figure 3, the gap 30 has an axial length of 0.43 mm.

Claims

Demands

1. Threaded joint (1) having a longitudinal axis (x), said joint comprising a first tubular component (Cl) and a second tubular component (C2), the first tubular component (Cl) and the second tubular component (C2) being screwed together, - the first component (Cl) comprising a first tube (10) and a male element (15) disposed at one end of said first tube (10), the male element (15) comprising successively from the first tube (10) to an internal male stop surface (13) of said male element: an external male stop surface (11), at least a first male threaded portion (12) having a variable width self-locking thread profile, and the internal male stop surface (13), - the second component (C2) comprising a second tube (20) and a female element (25) disposed at one end of said second tube (20), the female element (25) comprising successively from the second tube (20) to a female external stop surface (21) of said female element: a female internal stop surface (23), at least a first female threaded portion (22) having a self-locking, variable-width thread profile, a female lip (24), and the female external stop surface (21), a first axial length BSL between the female internal stop surface (23) and the female external stop surface (21) being greater than a second axial length PSL between the male internal stop surface (13) and the male external stop surface (11), the first axial length BSL and the second axial length PSL being such that a gap (30) is formed between the male external stop surface (11) and the female external stop surface (21),said gap (30) being capable of being closed by contact between the male external stop surface (11) and the stop surface, external female (21) when an axial compressive load is applied.

2. Tubular joint (1) according to claim 1, characterized in that the male external stop surface (11) has an inclination of angle α with respect to a first axis (y), said first axis (y) being perpendicular to the longitudinal axis (x), and in that the female external stop surface (21) has an inclination of angle P with respect to a second axis (y”), said second axis y” being perpendicular to the longitudinal axis (x), the angles α and P being such that the male external stop surface (11) and the female external stop surface (21) are substantially parallel.

3. Tubular joint (1) according to claim 2, characterized in that the angles a and P are such that: 0° < a < 30° and 0° <p<30°.

4. Tubular joint (1) according to claim 2, characterized in that the angles a and P are such that: 0° < a < 10° and 0° <p<10°.

5. Tubular joint (1) according to claim 2, characterized in that the angles a and P are such that: 0° < a < 5° and 0° <p<5°.

6. Tubular joint (1) according to claim 2, characterized in that the angles a and P both have a value of 0°.

7. Tubular joint (1) according to any one of the preceding claims, characterized in that the gap (30) has an axial length between 0.10 mm and 0.82 mm.

8. Tubular joint (1) according to any one of the preceding claims, characterized in that the gap (30) has an axial length such that: where BSL is in mm.

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