WO2022184992A1

WO2022184992A1 - Segmented threaded tubular element

Info

Publication number: WO2022184992A1
Application number: PCT/FR2022/050297
Authority: WO
Inventors: Pierre Martin; Jean-Guillaume Besse; Nicolas BAUDET
Original assignee: Vallourec Oil And Gas France
Priority date: 2021-03-03
Filing date: 2022-02-18
Publication date: 2022-09-09
Also published as: FR3120416A1; AR126037A1

Abstract

The invention relates to a tubular element (2, 20, 30, 40) comprising a body (4), the body having a first surface (3, 43) on which a thread (5, 45) is formed, a second surface (7, 47) radially opposite the first surface (3, 43), and a sealing surface (10, 50) located on the first surface (3, 43), said body (4) being made from a steel having a first yield strength Ys1, the tubular element comprising a segment (11, 21, 31, 41) extending radially from the second surface (7, 47) in line with the sealing surface (10, 50) and having a second yield strength Ys2 greater than the first yield strength Ys1.

Description

Title of the invention: Threaded tubular element with segment

Technical area

[1] The invention relates to the components, threaded tubular elements and seals resulting from the assembly of two threaded tubular elements present in the tubular components used in the field of oil and gas, geothermal energy, energy, and more particularly to a method of manufacturing such an element.

Technology background

[2] Here, “component” means any tube or accessory used to drill or exploit a well and comprising at least one connection or connector or even a threaded tubular element, and intended to be assembled by threading to another component to constitute with this other component a tubular threaded joint. The component may for example be a tube of relatively great length (in particular about ten meters in length), or else a tubular sleeve of a few tens of centimeters in length, or even an accessory of these tubular elements. In a non-limiting way, such an accessory can be a suspension device or "hanger", a section change part or "cross-over", a safety valve, a drill rod connector or "tool joint", " sub", and the like...

[3]Tube joints therefore consist of at least two threaded tubular elements. These threaded tubular elements are complementary allowing the connection of two tubular elements - one male ("Pin") and the other female ("Box") - between them. There is therefore a male threaded tubular element and a female threaded tubular element. The so-called premium or semi-premium threaded tubular elements generally comprise at least one abutment surface.

A first abutment may be formed by two abutment surfaces of two threaded tubular elements, oriented substantially radially and configured so as to be in contact with each other after screwing tubular elements threaded together, therefore in the assembled state or in the assembled state and during compressive stresses on the tubular joint. The stops generally have negative angles with respect to the main axis of the connections. A first abutment surface may be located on the distal end of a threaded tubular member, or on the side of the thread(s) located opposite the distal end of the threaded tubular member. Intermediate abutments are also known on joints comprising at least two levels of threads, an intermediate abutment surface being between the two threads of an element.

[4] In general, for technical and machining reasons, the different parts of the same component, whether it is the tubular element or the threaded ends, are designed according to one and the same type. of material (alloy or not).

[5]The so-called "premium" connections include sealing surfaces called sealing surfaces, at least one on the pin, and at least one corresponding on the box, intended to be brought into interfering contact when the pin and box connections are assembled with each other, so as to form a seal having a seal against liquids and/or gases. The sealing surfaces must maintain a seal preventing the passage of liquids and/or gases when the connections are assembled together and during the use of the tubes comprising these connections assembled in a column, for example an oil well column , that is to say that the sealing function must be maintained in the widest possible spectrum of use, including when the joint is subjected to internal pressure or to external pressure, to compressive stresses or tensile stresses, at room temperature or at high temperature, this spectrum corresponding to an operating range of the joint.

[6] In general, sealing surfaces are designed to work in the elastic range of the material that constitutes them so as to maintain the quality of sealing under various successive stresses.

[7]However, to ensure a good seal, the sealing surfaces must be assembled in such a way as to create high contact pressures. It may happen, especially during assembly, when high performance is sought, that too high contact pressures are reached, with risks of plastification, or risks of seizing. By seizing, we mean cases where material is torn off: In the event of seizing, the sealing function is seriously compromised.

[8] Furthermore, it is possible that the tightness of the joint is not maintained when the joint is stressed, the material supporting the sealing surfaces deforming with an amplitude of displacement of the sealing surface decreasing and canceling the interference, or even with rupture of contact of the sealing surfaces.

[9] There is a need to obtain a threaded tubular element which makes it possible to guarantee sealing even under significant stresses, while reducing the risks of seizing.

[10] The present invention aims to solve this problem with a tubular element comprising a body, the body comprising a first surface on which a thread is provided, a second surface radially opposite the first surface, a sealing surface located on the first surface, said body being in a steel having a first elastic limit Ysl, the tubular element comprising a segment extending radially from the second surface in line with the sealing surface and having a second elastic limit Ys2 greater than the first yield strength Ysl.

Thus, the material supporting the sealing surface has improved rigidity, and the seal resulting from the assembly of such a tubular element with another tubular element has improved sealing performance under stresses.

[11] According to one aspect, the segment has a radial contact surface with the body in line with the sealing surface. With such radial contact the sealing surface is supported, in particular radially, both by the body and by the segment so that the segment actively participates in reinforcing the rigidity of the tubular element at the level of the surface of sealing, the tubular element thus having at the level of the sealing surface a satisfactory radial stiffness.

[12] Thus, according to one aspect, said segment has a second elastic limit Ys2 greater than the first elastic limit Ysl so as to reinforce the structural rigidity, typically the radial stiffness, of the tubular element at the right of said sealing surface. [13] According to one aspect, the sealing surface of the tubular element is located axially between the thread and the distal end of the tubular element. The region towards the distal end generally being the region of lesser radial thickness of the threaded element, the effect of additional rigidity provided by the segment is stronger for such a location of the sealing surface.

[14]In another aspect, the distal end may include an abutment surface and the segment extend axially to said abutment surface and include at least a portion of the abutment surface. This makes it possible to increase the axial rigidity of the element from the abutment to the level of the sealing surface and to obtain a synergy between the segment, the abutment surface and the sealing surface. The sealing surface has a reduced displacement when the seal is subjected to a compression force. The length of the segment makes it possible to distribute the stresses exerted in the material around the sealing surface. More pressure can be exerted on the thrust bearing, which induces more contact pressure on the sealing surface via the segment. The segment also makes it possible to improve sealing when the seal is subjected to a tensile force, the segment stiffening the end carrying the sealing surface.

[15] The second surface may include a recess and the segment be located in said recess. The segment may be located entirely within the recess. This makes it possible to improve the rigidity of the end lip without adding thickness to said end lip. This can avoid reducing an internal diameter of the connection at the end lip. The segment can be only partially in the recess. The segment makes it possible to overcome the dimensional limitations linked to the methods of fattening and/or conification of the end of a tube.

[16] According to one aspect, the first elastic limit Ysl of the body and the second elastic limit Ys2 of the segment have values denoted [Ysl] [Ys2] such that [Ys2] >= 1.15 x [Ysl] and preferably [Ys2] >= 1.3 x [Ysl]

[17]According to another aspect, the segment can have a radial thickness decreasing away from the distal end. This makes it possible to increase the contact surface between the segment and the body of the connection. This allows directing the forces transmitted by the abutment surface in a radial direction and in the direction towards the inside of the connection.

[18]According to one aspect, the segment can be attached to the body by additive manufacturing. This allows better control of the shape and adhesion of the segment to the body. This also makes it possible to dimensionally limit the heat-affected zone.

[19]In one aspect, the segment has a radial thickness of at least 1.8 mm.

[20] Preferably, the segment (11) may have a thickness Ep greater than or equal to a minimum thickness Epmin such that:

[Math 1]

[21]Also, the segment can have a thickness Ep less than or equal to a maximum thickness Epmax such that Epmax = Min (Epmaxl; Epmax2) where:

[Math 2]

And

[Math 3]

[22] Where GD is the body-to-lip inside diameter, JID is the lip inside diameter, PCD is the lip outside diameter at the sealing surface.

[23] In one aspect, the segment may be located at a radial distance of at least 1.5 mm from the sealing surface. This ensures that the construction of the segment on the body does not influence the properties of the material adjacent to the sealing surface.

[24] In one aspect, the segment may have an axial length of at least 4 mm.

[25] Also, the segment may have an axial length at least equal to an axial length of the sealing surface plus at least 4 mm, the sealing surface being the sealing surface in line with which the segment lies radially. [26] According to another aspect, the segment does not include a recess arranged for the passage of fluid or gas, or a recess arranged to house a sensor.

[27]The segment can be in a metal chosen from alloy steels, high alloy steels, cupro-nickel alloys, titanium alloys, ceramics, glass-ceramics, or copper, cupronickel, stellite, ferrochrome.

[28]Alternatively, the segment can be in the same metal as the metal of the body. It is indeed possible to obtain different elastic limits with steels of the same nature.

[29]Finally, the invention is also a method for obtaining a tubular element as described above, said method possibly comprising a step of producing the segment by a method chosen from among hardfacing methods, fusion methods by beam of electrons, laser melting processes on a metal powder bed or "selective laser melting", selective laser sintering processes, direct metal deposition processes or "Direct Energy Deposition", Binder Projection Deposition or Deposition processes by Laser Projection, deposition processes by arc-wire additive manufacturing.

Brief description of figures

[30] The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given for illustrative purposes only. and non-limiting, with reference to the accompanying drawings.

[31] [Fig.1] Figure 1 is a sectional view of one end of a tubular element according to a preferred embodiment of the invention and with a male end of the threaded tubular element;

[32] [Fig.2] Figure 2 is a partial sectional view of one end of a tubular element according to the invention in a first variation;

[33] [Fig.3] Figure 3 is a partial sectional view of one end of a tubular element according to a second variant of the invention;

[34] [Fig.4] Figure 4 is a partial sectional view of one end of a tubular element according to another variant of the invention;

Description of embodiments [35] Figure 1 shows a preferred embodiment of the invention. Figure 1 shows a partial sectional view of a tubular element (2) having a main axis (X) comprising a male end or connection, comprising a first surface (3) on which is provided a thread (5) which is here an external thread, a male sealing surface (10), a distal end (8). In the example of Figure 1, the tubular element (2) comprises on the distal end (8) an abutment surface (9).

[36] The tubular element comprises a body (4) in a first material, here a first steel having a first yield strength Ysl. The thread (5), the sealing surface (10) are made in the body (4) and are therefore constituted by said first steel of first yield strength Ysl. The thread (5) and the sealing surface (10) are generally obtained by machining in the body of the tubular element (2).

[37]The connections can also comprise several stages of threads, for example two stages of threads. Connections can also comprise additional sealing surfaces, for example a sealing surface located on the side of the external thread (5) which is opposite to the distal end (8), or even a sealing surface located between two thread stages. The connections can also include an abutment surface located axially between the two thread stages. The connections may have no abutment surface.

[38] The tubular element (2) of Figure 1 comprises a segment (11). The segment (11) extends from a second surface (7) radially opposite the first surface. The second surface here is an internal surface. The axial location of the segment (11) is such that the segment (11) is located in line with the sealing surface (10). In the embodiment of Figure 1, the segment (11) extends on the one hand beyond the axial position of the sealing surface (10) on the side opposite the distal end (8), and the segment (11) extends on the other hand towards the distal end (8). In this embodiment, the segment (11) extends to the distal end (8).

[39]The segment (11) is in a steel having a second yield strength Ys2. This elastic limit is advantageously greater than the first elastic limit Ysl. This makes it possible to make the end lip of the tubular element (2) more rigid, the end lip being the part of the element tube (2) located between the thread (5) and the distal end (8). This greater rigidity is therefore obtained at the level of the sealing surface (10). Consequently, when, in use, the tubular element is subjected to stresses such as external pressure, bending, the end lip stiffened by the segment deforms less, and the sealing surface maintains a contact more long with a corresponding sealing surface on a corresponding tubular element. The sealing performance of the connection is improved. This improved performance can be obtained without increasing the interference at the level of the sealing surfaces in contact in a joint formed of two connections, which makes it possible not to increase the risks of seizing when the connections are assembled.

[40] Advantageously, the body (4) of the tubular element comprises a recess (14) formed on the second surface (7). The segment (11) is located in the recess (14). The segment can be added to the body (4) without the presence of a recess on the second surface (7), which can be advantageous when the material available at the end of the tubular element is too low, but which can have the disadvantage in certain cases to reduce the free internal diameter, which can be inconvenient for example for the passage of components inside the tubular element.

[41] The segment (11) is an addition of material arranged to reinforce the structural rigidity of the end lip of a tubular element. The highest limit of the Ys2 elastic limit of the segment makes it possible to reduce the bulk volume of added material. The presence of a recess (14) in the body (4) and the positioning of the segment (11), in part or in whole, makes it possible to further reduce the size, and even to have no additional size.

[42]Tests carried out have shown that a difference in elastic limit such that the second elastic limit Ys2 of the segment (11) is greater than or equal to 1.15 times the first elastic limit of the body Ysl provides a significant improvement. When the second elastic limit Ys2 of the segment (11) is greater than or equal to 1.3 times the first elastic limit of the body Ysl, the performance obtained is even better.

[43] The segment (11) can be made of a steel having the same chemical composition as the steel of the body (4) and which has a second limit of elasticity Ys2 nevertheless higher than the first elastic limit Ysl of the body, because of a distinct crystalline structure. This distinct crystal structure is achieved by heat treatment. A very satisfactory method to date is to deposit material from the segment by a known additive manufacturing method, which makes it possible to deposit drops of molten material which undergo rapid cooling during deposition, which creates a steel with yield strength higher than that of the steel of the body (4) which is shaped by methods resulting in a longer cooling cycle.

[44] Alternatively, the segment (11) can be made of a second steel with a different chemical composition from that of the first steel of the body (4), the second steel of the segment inherently having a higher elastic limit than the first body steel (4). In this case, the material of the segment (11) is also deposited by an additive manufacturing process. For example, such a steel can be a Ferro 55 alloy from Boehler-Voestalpine, Deloro-Stellite-Kennametal, Carpenter, Erasteel, Hoganas. The steel can be chosen from alloy steels, high alloys, cupro-nickel alloys, titanium alloys, ceramics, glass-ceramics, or copper, cupronickel, stellite, ferrochrome, having suitable elasticity limits for use on a tubular element.

[45] The deposit, or assembly of the segment (11) on the body (4) is generally exothermic. The tests carried out by the applicant have shown that when the segment (11) is located at a radial distance of at least 1.5 mm from the sealing surface (10), the sealing surface is not affected by the process for adding material from the segment (11) to the body (4). This is why the segment (11) is located at a radial distance of at least 1.5 mm from the sealing surface (10) at all points.

[46]The segment (11) of figure 1 must have a thickness of at least 1.8 mm. By thickness is meant the size of the profile of the segment measured radially.

[47]The thickness is determined in line with the sealing surface in a radial direction. A sealing surface having an axial length, the thickness can be measured on any straight line in the radial direction and passing through a point on the sealing surface. [48]Nevertheless, a segment (11) can be attached to tubular elements (2) of very variable sizes. The thickness of the segment can be adapted to these different sizes. The applicant has determined the preferred minimum and maximum thicknesses for a segment, thicknesses depending on the tubular element.

[49]Thus, the segment (11) can have a thickness Ep greater than or equal to a minimum thickness Ep _min such that:

[Math 4]

[50]Where Ysl is the elastic limit of the material of the body (4), Ys2 the elastic limit of the material of the segment, GD is the diameter of the bottom of the recess (14), JID is the internal diameter of the second surface in distal end, PCD is the diameter of the first surface at the sealing surface.

[51]If the result of equation 1 is less than 1.8, then the minimum thickness is 1.8 mm.

[52] Advantageously, the thickness of the segment (11) can be limited to a thickness Ep less than or equal to a maximum thickness Epmax such that: [Math 5]

Where

[Math 6]

Where

[Math 7]

[53]Finally, for the scenarios where the Ep _min value is greater than or equal to the Ep _max value, it is advisable to take the Ep _min value as the nominal thickness of the segment. It will be understood that the thickness values are those which the segment must have in line with the sealing surface. [54] The segment (11) has a length measured axially of at least 4 mm. This makes it possible to obtain a stiffening effect of the lip at the level of the sealing surface, and to cover different positions of a sealing point when the tubular element is subjected to different stresses, the sealing surfaces in contact that can move relative to each other a certain distance. Preferably, the segment (11) has an axial length at least equal to the axial length of the sealing surface plus 4 mm in order to reinforce the stiffening effect.

[55] The tubular element (20) of Figure 2 is similar to that of Figure 1, comprises a segment (21) located in line with a sealing surface (10), said segment (21) differing from the first embodiment in that the segment (11) does not extend to the distal end (8). Advantageously, the segment (11) does not modify the nature of the abutment surface (29) of the distal end (28). This embodiment is particularly suitable for modifying an existing tubular element, because it does not directly modify the functional surfaces such as the abutment surfaces, and thus their behavior during screwing is not or only slightly modified, and can reduce the need for certain requalifications of a product thus modified.

[56]The segment (21) has an axial length of at least 4 mm. Preferably, the segment (21) has an axial length at least equal to the axial length of the sealing surface plus 4 mm. These minimum length values also apply to other embodiments.

[57] The segment (21) is located in a recess (24) made in the second surface (7). The segment (21) is completely contained within the recess (24). Alternatively, the segment (21) can also be located partially outside the recess (24).

[58] Similarly to the embodiments of Figures 1 and 2, the tubular element (30) of Figure 3 comprises a body (4), the body (4) comprises a first surface (3) on which are provided a thread (5) and a sealing surface (10). The tubular member includes a distal end (38), said distal end including an abutment surface (39). An abutment surface is oriented substantially radially, is arranged to come into contact with a complementary abutment surface of a connection of a corresponding tubular element with which the tubular element (30) is assembled. [59] A segment (31) extends radially from a second surface (7) opposite the first surface (3), the segment (31) is located radially in line with the sealing surface (10), the segment (31) extends to the distal end (38) of the tubular member (30), and the segment entirely includes the abutment surface (39). The segment (31) does not include the sealing surface (10). Thus, all the contact forces at the abutment are transmitted by a homogeneous abutment surface in material. Advantageously, the contact surface between the body (4) and the segment (31) is conical so as to increase the contact surface between the body (4) and the segment (31). Advantageously, the section of this conical surface is such that its diameter increases towards the distal end, in this way the contact forces exerted on the abutment induce a better distribution of the stresses towards the sealing surface (10).

[60]The second surface (7) includes a recess (34). Segment (31) is partially contained within recess (34).

[61] For all embodiments, the segment does not include any porosity or channel allowing the passage of gas or liquids. The segment does not include a recess to house a sensor. These characteristics can apply to all the embodiments described in this application.

[62] The embodiments described describe a male connection but the characteristics described also apply to a female connection. By way of illustration, Figure 4 shows a portion of tubular element (40) of the embodiment of Figure 1 in the variant of a female connection.

The tubular element (40) of FIG. 4 comprises a first surface (43) comprises a body (4), a distal end (48), an abutment surface (49).

The body (4) comprising a thread (45), a sealing surface (50). The tubular element (40) includes a segment (41). The segment (41) extends from a second surface (47) radially opposite the first surface (43). The second surface here is an outer surface. The axial location of the segment (41) is such that the segment (41) is located in line with the sealing surface (50). In the embodiment of Figure 1, the segment (41) extends on the one hand beyond the axial position of the sealing surface (40) on the side opposite the distal end (48), and the segment (41) extends on the other hand towards the distal end (48). In this embodiment, the segment (41) extends to the distal end (48). The segment (41) is located in a recess (44). The other characteristics described for the embodiment of FIG. 1 apply to this embodiment.

[63]Comparative tests were carried out between a state-of-the-art connection and a connection, said connection being obtained by modifying a state-of-the-art connection to incorporate a segment according to the first embodiment according to Figure 1, the segment being completely located in a recess. The nominal connection diameter is 177.8 mm (7 inches), the base steel is a PI 10 alloy according to API 5CT. The segment is also made of PI 10 steel, added by additive manufacturing, more precisely by laser powder projection. Screwing tests and then tightness tests under stress were carried out with the parts produced. A screwing test is a series of 10 assemblies/disassemblies. Leakage is tested using internal gas pressure and then external liquid pressure methods. During the screwing tests, none of the test specimens according to the invention suffered from seizing. The "reference 1" comparative example suffered from seizing after the 3rd ^screwing and unscrewing, while the "specimen 1" according to the invention succeeded in making 10 screwing/unscrewing operations without seizing. The "reference 2" comparative examples had failed the sealing tests under external pressure, while the “specimen 2” according to the invention passed the sealing tests. Thus, the invention makes it possible to increase the sealing performance under stress compared to a connection not comprising the invention, without the seizing performance being affected.

[Table 1]

[64]According to another aspect, the invention also relates to a method for obtaining a threaded tubular element comprising a segment. This method comprises the step of choosing a tubular element with a thread, optionally making a recess on the surface opposite to the surface on which the thread is located, then depositing material in the recess or on said opposite surface .

[65] The deposition of material can be done according to a process chosen from reloading processes, electron beam fusion processes, laser fusion processes on a metal powder bed or "selective laser melting", selective laser sintering, direct metal deposition or “Direct Energy Deposition” processes, deposition processes by Binder Projection or Laser Projection Deposition, deposition processes by arc-wire additive manufacturing.

[66]After deposition of material so as to produce the segment, the tubular element can be machined at the distal end in order to produce an abutment surface.

Claims

[Claim 1] Tubular element (2, 20, 30, 40) comprising a body (4), the body comprising a first surface (3, 43) on which is provided a thread (5, 45), a second surface (7 , 47) radially opposite the first surface (3, 43), a sealing surface (10, 50) located on the first surface (3, 43), said body (4) being of a steel having a first limit of elasticity Ysl, the tubular element comprising a segment (11, 21, 31, 41) extending radially from the second surface (7, 47) in line with the sealing surface (10, 50), the segment ( 11, 21, 31, 41) having a radial contact surface with the body (4) in line with the sealing surface (10, 50), said segment (11, 21, 31, 41) having a second limit d elasticity Ys2 greater than the first elastic limit Ysl so as to reinforce the structural rigidity of the tubular element (2, 20, 30, 40) in line with said sealing surface (10, 50).

[Claim 2] A tubular element (2, 20, 30, 40) according to claim 1 comprising a distal end (8, 28, 38, 48), and wherein the sealing surface (10, 50) is located axially between the thread (5, 45), and the distal end (8, 28, 38, 48).

[Claim 3] A tubular element according to claim 2 wherein the distal end (8, 28, 38, 48) comprises an abutment surface (9, 29, 39, 49) and the segment (11, 21, 31, 41 ) extends axially to said abutment surface (9, 29, 39, 49) and includes at least a part of the abutment surface (9, 29, 39, 49).

[Claim 4] Tubular element according to one of the preceding claims, in which the second surface comprises a recess (14, 24, 34, 44) and the segment (11, 21, 31, 41) is located in the said recess (14, 24, 34, 44).

[Claim 5] Tubular element according to one of the preceding claims, in which the first elastic limit Ysl and the second elastic limit Ys2 have values denoted [Ysl] [Ys2] such that

and preferably

[ysl]

[Claim 6] Tubular element according to one of the preceding claims, in which the segment (11, 21, 31, 41) is attached to the body (4) by additive manufacturing.

[Claim 7] Tubular element according to one of the preceding claims, in which the segment (11, 21, 31, 41) has a radial thickness of at least 1.8 mm.

[Claim 8] Tubular element according to one of the preceding claims, in which the segment (11, 21, 31, 41) has a radial thickness which decreases away from the distal end (8, 28, 38, 48). .

[Claim 9] Tubular element according to claim 8 in which the segment (11, 21, 31, 41) has a thickness Ep greater than or equal to a minimum thickness Ep _m in such that:

[Math 8]

[Claim 10] Tubular element according to one of Claims 7 or 9, in which the segment (11, 21, 31, 41) has a thickness Ep less than or equal to a maximum thickness Epmax such that Epmax = Min (Eplmax; Ep2max) ; where :

[Math 9]

And

[Math 10]

[Claim 11] Tubular element according to one of the preceding claims, in which the segment (11, 21, 31, 41) is located at a radial distance of at least 1.5 mm from the sealing surface (10, 50 ).

[Claim 12] Tubular element according to one of the preceding claims, in which the segment (11, 21, 31, 41) has an axial length of at least 4 mm.

[Claim 13] Tubular element according to one of the preceding claims, in which the segment (11, 21, 31, 41) has an axial length at least equal to an axial length of the sealing surface (50, 10) plus at least 4 mm.

[Claim 14] Tubular element according to one of the preceding claims, in which the segment (11, 21, 31, 41) is made of a metal chosen from alloy steels, high alloy steels, cupro-nickel alloys, titanium alloys, ceramics, vitroceramics, or copper, cupronickel, stellite, ferrochrome.

[Claim 15] Tubular element according to one of the preceding claims, in which the segment (11, 21, 31, 41) is made of the same metal as the metal of the body (4).

[Claim 16] Method for obtaining the tubular element of one of the preceding claims, characterized in that it comprises a step of producing the segment (11, 21, 31, 41) by a method chosen from among the methods of hardfacing, electron beam melting processes, laser melting processes on a metal powder bed or "selective laser melting", selective laser sintering processes, direct metal deposition processes or "Direct Energy Deposition", processes Deposition by Binder Projection or Deposition by Laser Projection, arc-wire additive manufacturing deposition processes.