OA20570A - Threaded connection having a dissymmetrical helical profile. - Google Patents

Abstract

Threaded tubular connection for the casing of hydrocarbon wells obtained by makeup of a male tool joint with a female tool joint, the connection comprising a threaded portion (16a, 18a), such that the male and respectively female threaded portions each comprise a helix provided with a load flank, a thread crest, a stabbing flank, a thread root, such that a pitch of the load flank (LFLp, LFLb) and a pitch of the stabbing flank (SFLp, SFLb) fulfils the following condition: [Math 22] SFLb = LFLb = SFLP = LFLP = k, A tooth width (Wtp) of the male helix and a tooth width of the female helix (Wtb) are such that [Math 23] or [Math 24] and [Math 25] Wtp + Wtb < k Threaded tubular connection for the casing of hydrocarbon wells obtained by makeup of a male tool joint with a female tool joint, the connection comprising a threaded portion (16a, 18a), such that the male and respectively female threaded portions each comprehending a helix provided with a load flank, a thread crest, a stabbing flank, a thread root, such that a pitch of the load flank (LFLp, LFLb) and a pitch of the stabbing flank (SFLp, SFLb) fulfills the following condition: [Math 22] SFLb = LFLb = SFLP = LFLP = k, A tooth width (Wtp) of the male helix and a tooth width of the female helix (Wtb) are such that [Math 23] or [Math 24] and [Math 25] Wtp + Wtb < k

Description

Description

Title of the invention: Threaded connection having a dissymmetrical helical profile

The present invention relates to connections or assemblies of tubes intended to be 5 connected by means of threadings and relates to the tubes used in industry and in particular threaded assemblies orjunctions intended to equip tubing strings or production tubing accessories or casing strings for the exploration, prospecting or exploitation of oil or gas wells, as well as threaded assemblies orjunctions used for any application in which it may be necessary to assemble pipelines or tubing accessories such as for example in the geothermal 10 energy industry' or in steam production. The threaded assembly according to the invention is particularly useful for the assembly of métal tubes used for the casing of oil or gas wells as explained hereinafter.

In tins text, the words “assembly” or “connection” or “junction” or “joint” are used with the same meaning, except for particular contexte. By “tubes” is meant any type of tabes 15 or tubular components or tubing accessories existing or suitable for utilisation in industry, these tabes in general being métal tabes. In particular, these tubes are seamless tubes obtained from Steel such as those defined in API Spécification 5 CT, or also according to the Standard ISO 11960:2004. Preferably, a connection according to the invention is obtained between tabes produced from a material having a high-capacity breaking strength, for example steels of a grade comprised between 862 and 965 MPa (between 125 and 140 ksi).

Numerous types of assembly for oil or gas tubes are known which give satisfactory results from the point of view of mechanical characteristics and sealing, even under harsh conditions of use. Some of these assemblies require tubes, equipped with male frustoconical threadings at the two ends which are assembled by means of couplings having two corresponding female frustoconical threadings. This mode of assembly has the advantage of making the two components of the assembly rigid, due to the existence of positive interférences that can be created between male threading and female threading. These are threaded and coupled connections, also called T&C connections.

However, the outer diameter of these couplings is greater than that of the 30 corresponding tabes and, when these assemblies are used in casing tubes, requires the production of borcholes of increased diameter. In the case of very' deep wells, of a depth exceeding 4000 m, the casing will need to descend deeper into the well, and it is known that assemblies without a coupling are preferred, as taught in documents US 2992019,

EP 0767335 or also US 2013/0015657. In this case, the tubes each comprise an end equipped with a male tool joint and a second end equipped with a female tool joint. The tubes are assembled end-to-end by connections between male and female tool joints. These assemblies are denoted by the terni “intégral”.

In order to respond to increased needs for résistance to internai and extemal pressures, an intégral connection is known from document US 4662659 equipped with two staggercd threaded portions on either side of an intermediate abutment, this intermediate abutment being designed with a négative angle in order to increase the résistance to pressures. In addition, on one side of this intennediate abutment, or on either side of this intennediate abutment, the document teaches sealing zones by radial interférence between conical surfaces, the taper angles of which are slightly modified with respect to one another by an angle y. According to this document, the seal is provided exclusively centrally, between the two threaded portions, in proximity to the intermediate abutment. Document US 2019 0040978 proposes an alternative to document US 4662659, by specifying a particulargeometry of these seals on either side ofthe intermediate abutment, and by modifying the shape of the threading and by choosing a threading having a dovetail profile.

Moreover, another connection is known from document US 2017 0101830, equipped with two staggercd threaded portions on either side of an intermediate abutment. According to this document, a seal is provided between a threaded portion and this intermediate abutment. Now, the définition of this seal reduces the performance and tire capacity ofthe intermediate abutment, so this document teaches providing an additional abutment surface at the level of the distal end of the male tool joint. Alternatively, other documents propose modifying the threading in order to compensate for the lower performance of the intermediate abutment under compression. These alternative threadings are thus called “dovetail” threadings and are made up in such a way as to obtain a locking together of the threaded portions. To this end, the threaded portions are proposed with a pitch value that is different for the load flank and for the stabbing flank, so that the hélix of this threading proposes a tooth width which increases progressively with the tums of the hélix, from one end to the other, the hollows defined between the spires of this hélix reducing according to the same progression. Thus, the makeup of the threaded portions is carried out until contact is obtained between stabbing flanks, but also between load flanks. While this type of connection, called “self-lockmg wedge thread”, is very effective, it is, however, very difficult to machine and to master at the moment of assemblv.

Despite the varions solutions that are already known, a need has therefore arisen to facilitais the machining of an intégral connection which is suited to forming casings for very deep well s, the performance with respect to résistance to the cycles of internai pressures and extemal pressures, as well as the tolérances under traction and compression, are neverthelcss achieved, while accepting the inhérent machining and assembly tolérances in the field of oil or gas tubes. Tn practice, it has also become apparent that the manner in which the assembly grease was applied on the joints was a factor of the first order in successfully making a connection. Tire threaded connection according to the invention makes it possible to better tolerate the handling variations at tire moment of application of a quantity of grease.

The benefit of the invention is to propose an intégral connection which re s ponds to technical requirements close to those of sleeve couplings, and which makes it possible to hâve an effectiveness close to that ofthe tube. In particular, a connection according to the invention can hâve an effectiveness equal to 96% of the effectiveness of dre tube. The effectiveness is in general defined as being the relationship between the critical section of the connection and tire cross-section of a regular portion of a tube between the two ends of a component. The cntical section of the connection is equal to the smallest critical section of the male tool joint or of the female tool joint.

The invention applies preferentially to threaded comrections having a large diameter, in particular to tubes having an outer diameter greater than 177.8 mm (7 inches), preferentially greater than 254 mm (10 inches), for example 406.4 mm (16 inches).

The invention proposes a connection with better adhesion in these respects.

The subject of the invention is a threaded tubular connection for the drilling and/or exploitation of hydrocarbon wells, comprising a first tube equipped at a first distal end with a male tool joint and a second tube equipped at a second distal end with a female tool joint, the male tool joint being capable of being assenrbled by makeup with the female tool joint, the first tube asseinbled to the second tube together defîning a longitudinal axis, the male tool joint comprising a male threaded portion, the female tool joint comprising a female threaded portion engaged with the male threaded portion when the connection is assembled, the male and female threaded portions each comprising at least one hélix equipped with a toad flank, a thread crest, a stabbing flank, a thread root, such that a pitch of the load flank LFLp and a pitch of the stabbing flank SFLp of the male threaded portion, and respectively a pitch of the load flank LFLb and a pitch of the stabbing flank SFLb of the female threaded portion fulfil the foliowing condition, for at least two consecutive tums of the respective helices of the male and female threaded portions:

[Math 1]

SFLp = LFLp = SFLb = LFLb = k and such that along the longitudinal axis, in these at least two consecutive tums, a tooth width (Wtp) of the hélix of the male threaded portion and a tooth width of the hélix of the corresponding female threaded portion (Wtb) are such that

[Math 2]

Wtp

50% < 777T < ⁸⁰%

Wtb

Or

[Math 3]

50% < — < 80% Wtp

And

[Math 4]

Wtp + Wtb < k

Preferably, the connection can fulfil the following condition

[Math 5]

Wtp ^^%<·^^<75% Or even the following condition

[Math 6]

W tp ^67% < w^ ^{< 73%}

The tooth width of the hélix of the male threaded portion can be comprised between 2.5 and 3.5 mm. And for example, the tooth width of the hélix ofthe female threaded portion can be compnsed between 3.7 and 4.5 mm.

Preferably, the tooth widths ofthe helices ofthe male and respectively female threaded portions can fiilfil the following condition:

[Math 7]

Wtp + Wtb < k — 0.1 mm over said at least two consecutive tums of these helices, so that these at least two tums may not be self-locking.

Tire tooth widths of the complété helices of the male and respectively female portions can fulfil the following condition: for each tum (n), a tooth width ofthe male threading (Wtp n) and a tooth width of the female threading (Wtb n) are such that for each n:

[Math 8]

Wtpn + Wtbn < k — 0.1 mm

Advantageously, a part of the stabbing flank can be parallel to a part of the load flank, with a tolérance of +/- 0.25° in the inclination of these parts relative to the longitudinal axis. The stabbing flanks can thus contribute to take up of compressive load.

The stabbing flank and the load flank of the hélix of the male threaded portion can be respectively rectilinear, and respectively connected by blending radii to the adjacent thread crest and thread root. In this case, the stabbing flank of the hélix of the female threaded portion can also comprise a rectilinear segment connected to the thread crest by a segment that is inclined with respect to the stabbing flank so as to propose a convexity, such that these two segments form between them an obtuse angle (86d) comprised between 190° and 260°, for example of the order of 225°. This convexity makes it possible to guarantee the absence of contact with the portion of the thread root 61 and concave curved transition 62.

The thread root of the hélix of the male threaded portion can comprise two segments, a first male thread root segment situated on the side of the stabbmg flank and a second male thread root segment situated on the side of the load flank, and such that a radial distance of the first male thread root segment is equal to or greater than the radial distance of the second male thread root segment, the radial distances being evaluated relative to a thread crest adjacent to said thread root of the hélix of the male threaded portion.

The load flank of tire hélix of the male threaded portion can form an angle comprised between 1° and 5°, preferably between 1.25 and 3.75° with respect to a normal to the longitudinal axis, and is parallel to the load flank of the hélix of the female threaded portion, with a tolérance of +/- 0.25° in the inclination of these load flanks with respect to the longitudinal axis.

In partîcular, the load flank of the hélix of the male threaded portion can form with an adjacent thread root of this hélix an angle less than or equal to 90°.

For example, the hélix of the female threaded portion can be frustoconical, preferably exclusively frustoconical, for example having a taper comprised between 5% and 15%, preferentially 8% and 12%. In this case, the hélix of the male threaded portion can also comprise at least a frustoconical part having a taper identical to that of the hélix of the female threaded portion.

According to a particular embodiment of the invention, the pitch of the load flank LFLp and the pitch of the stabbing flank SFLp can be comprised between 5 and 20 mm, preferentially between 6 and 8 mm.

In a preferred embodiment of the invention, the male threaded portion, and respectively the female threaded portion can each comprise a single hélix. In this case, the helices of the male threaded portion and respectively the female threaded portion can comprise at least 3 tums, preferably at least 4 tums.

In order to facilitate the assembly, the thread crests and the thread roots of the male and female threaded portions can hâve ataper less than the taper of said threaded portions, 10 for example they can be parallel to the longitudinal axis of the connection. In this case, a radial height of a stabbing flank of the male threaded portion can be greater than a radial height of a load flank of this male threaded portion.

Other features and advantages of the invention will become apparent on reading the detailed description below, with reference to the attached drawings, which show:

[Figure 1 ] : an external profile view of a first tube according to the invention,

[Figure 2]: a longitudinal cross-section view of a second tube according to the invention,

[Figure 3]: a partial longitudinal cross-section view of a male tool joint of the first tube in Figure i;

[Figure 4J: a partial longitudinal cross-section view of a female tool joint of the second tube in Figure 2;

[Figure 5]: a partial longitudinal cross-section view of a male tool joint of the first tube in Figure 1 assembled to a female tool joint of the second tube in Figure 2, this crosssection view also indicating the stress levels reached inside the connection after assembly;

| Figure 6] : a partial longitudinal cross-section view of a female non-threaded intennediate portion of a female tool joint according to tbe invention,

[Figure 7]: a partial longitudinal cross-section view of a male non-threaded intermediate portion of a male tool joint according to the invention;

[Figure 8): a partial longitudinal cross-section view of a female non-threaded inner 30 portion of a female tool joint according to the invention;

[Figure 9]: a partial longitudinal cross-section view of a male non-threaded inner portion of a male tool joint according to the invention;

[Figure 10]: a partial longitudinal cross-section view of a male threaded portion of a male tool joint according to the invention,

[Figure 11]: a partial longitudinal cross-section view of atootli of a male threaded portion according to Figure 10;

[Figure 12]: a partial longitudinal cross-section view of a female threaded portion of a female tool joint according to the invention;

[Figure 13]: a partial longitudinal cross-section view of atooth of a female threaded portion according to Figure 12;

[Figure 14]: a partial longitudinal cross-section view ofthe male threaded portion of Figure 10 in an assembled position with the female threaded portion of Figure 12;

[Figure 15] : a partial longitudinal cross-section view of a groove for evacuating the excess pressure of grease formed in a female threaded portion of a female tool joint according to the invention.

As can be seen in Figure 1, a first tube 12 comprises a tube body 120. This first tube 12 has an axial length of severai mètres in length, for example of the order of 10 to 15 m in length. It extends along a longitudinal axis X. At a first axial end 121 of this first tube 12, the first tube 12 comprises a male tool joint 18. The tube body 120 comprises an outer diameter, generally denoted nominal outer diameter. Opposite the first axial end 121, the first tube comprises a second axial end 122. This second axial end 122 has an outer diameter greater than that ofthe tube body 120.

Figure 2 shows a longitudinal cross-section view of a second tube 14, identical to the first tube 12. This second tube 14 comprises a tube body 140 equipped at a first axial end 141 with a male tool joint and at a second axial end 142, a female tool joint 16. The male tool joint is machined on the outer surface of the first axial end 121. The second axial end 142 has an outer diameter greater than that of the tube body 140. Oie female tool joint is machined on the inner surface of this second end.

A connection will be described in the description hereinafter, formed between the female tool joint 16 of the second tube 14 with the tool joint 18 of the first tube 12. For example, Figure 5 shows a connection according to the invention. This connection is called semi-flush, insofar as the outer diameter at the Ievel of the connection formed is less than 105%oreven 103% ofthe outer diameter ofthe tube bodies 120, 140. The invention applies to connections that can be flush, namely for which the outer diameter at the Ievel of the connection is less than 101 % of the nommai outer diameter ODnom.

In the example described, the first and second tubes 12 and 14 are identical, and each comprises a male tooljoint 18 attire respective first end 121 and 141 thereof, and each also comprises a female tool joint 16 at the respective second end 122 and 142 thereof.

Before machining the male tool joint 18, the first distal end 121, 141 is tapered. The tapering results in a réduction of the inner diameter of the first end 121, 141, starting from a narrowing 13 forming a transition between the tube body and the first end. Preferably, the inner diameter of the first end is restricted with respect to the nominal inner diameter of the tube body, so that after assembly of the connection, the inner diameter at the level of the connection is grcater than 94% of the nominal inner diameter. The first end 121, 141 extends between a free edge 19 and the tube body. This first end bearing a male tool joint 18 represents a certain axial length, of the order of 20 to 30 cm, between the free edge 19 and the tube body.

Likewise, before machining the female tool joint 16 at the level of the second distal end 122, 142, the second end undergoes a diamétral expansion. As shown in Figures 1 and 2, the diamétral expansion 15 occurs at a distance from the free edge 17 of the second axial end 122, 142, such that the second axial end 122, 142 represents a certain axial length, ofthe order of 20 to 30 cm, between the free edge 17 and the tube body.

The male tool joint 18 comprises two threaded portions, respectively 18a and 18b. These two threaded portions extend along two successive portions along the axis X. They are spaced spart from one another by a ποη-threaded intennediate portion 20. The male threaded portions 18a and 18b are offset radially with respect to the axis X. In fact, the male tool joint 18 comprises a male abutment shoulder 22 in the non-threaded intennediate portion 20. Tire male intermediate abutment 22 defines an annular surface in a plane perpcndicular to the axis X. Preferably, the male threaded portions Ï8a and 18b each comprise a single spire forming a single hélix. Preferably, the pitch of the helices of each of the threaded portions is identicaï.

Between the free edge 19 and the first threaded portion 18a, a male non-threaded inner portion 30 comprises an inner sealing surface 25.

Between the male intennediate abutment 22 and the second male threaded portion 18b, the male non-threaded intermediate portion 20 comprises an intermediate sealing surface 26.

The female tool joint 16 comprises two threaded portions, respectively 16a and 16b. These two threaded portions extend along two successive portions along the axis X. They are spaced apart from one another by a non-threaded intennediate portion 2 i. The female threaded portions 16a and 16b are offset radially with respect to the axis X. In fact, the female tool joint 16 comprises an intermediate abutment shoulder 24 in the non-threaded intennediate portion 21. The female intermediate abutment 24 defines an annular surface in a plane perpendicular to the axis X. Preferably, the male threaded portions 18a and 18b each comprise a single spire forming a single hélix. Preferably, the pitch of the helices of each of the male and female threaded portions is identical.

Between the tube body 14 and the first threaded portion 16a, the female tool joint 16 comprises a female non-threaded inner portion 31 comprising an mner sealing surface 27.

Between the intermediate abutment surface 24 and the second female threaded portion 16b, the female non-thrcaded intermediate portion 21 comprises an intermediate sealing surface 29.

In the assembled position of the connection, in Figure 5,

- the free edge 19 remains at a non-zero axial distance “d”, for example more than 0.1 mm from the female tool joint 16;

- the hélix of the first male threaded portion 18a is engaged in that of the first female threaded portion 16a,

- the helix of the second male threaded portion 18b is engaged m that of the second female threaded portion 16b,

- the male intermediate abutment 22 cornes into abutting contact with the female intermediate abutment 24,

- the male inner sealing surface 25 cornes into interférence contact radially with the female inner sealing surface 26 in order to form an inner metal-metal seal protecting the connection from internai pressure loading,

- the male intermediate sealing surface 27 cornes into interférence contact radially with the female intermediate sealing surface 28 in order to form an intermediate metal-metal seal protecting the connection from extemal pressure loading,

- the free edge 17 of the female tool joint is at a non-zero axial distance from the maie tool joint.

The connection according to the invention comprises a single axial abutment, orthogonal to the axis X, obtained by the contact between the intermediate abutments 22 and 24, and the main fonction of which is to mark the end of the makeup of the connection.

A radial thickness of the surfaces in contact with these intermediate abutments 22 and 24 is less than 20% of the cross-section of the tube 120 or 140, this cross-section being delimited between ODnom and IDnom. The machining of the male and female tool joints allows a manufacturing tolérance which makes it possible to use any compilant tube the dimensions ODnom and IDnom of which are compilant with the tolérances ofthe spécifications set in the API standards. The intermediate abutment nevertlieless makes it possible to absorb a portion of the compressive stresses of the connection, but the dimcnsioning thereofdoes notmake it possible to absorb ail ofthe compressive loading.

On either side of the inner metal-metal seal, the male non-threaded inner portion 30 is at a non-zero radial distance from the female non-threaded inner portion 31. The inner metal-metal seal is produced at a distance from the edges of this inner non-threaded zone 3031,

Except at the level of the contacts obtained for the intermediate metal-metal seal and for the abutment ofthe abutment shoulders 22 and 24, the male non-threaded intermediate portion 20 is at a non-zero radial distance from the female ποη-direaded inner portion 21. The intermediate metal-metal seal is produced at a distance from the edges of this intermediate non-threaded zone 20-21.

As can be seen in Figure 2, the inner metal-metal seal receives more stresses than the intermediate seal. The intermediate seal is useful for ensuring the seaiing under external pressure stresses. Between the second threaded portion and the intermediate abutment, the intermediate seal thus has a thickness of the male tool joint 18 and of the female tool joint 16 at the level of this seaiing surface which allows it to hâve a high contact stability, in particular under high tensile loading: there is no detachment of the surfaces.

In detail, in Figures 6 and 7, according to an embodiment of the invention, the intermediate seal is of the cone-to-cone type. The male intermediate seaiing surface 27 and the female intermediate seaiing surface 28 are frustoconical having identical taper. Altematively, these surfaces 27 and 28 can hâve a substantially identical taper, in the sense that the taper of one can be comprised between + and - 1% of the taper of the other. For example, the taper of these surfaces 27 and 28 is comprised between 15 and 25%, for example equal to 20% +/- 1%, or also both equal to 20%.

The male intermediate seaiing surface 27 is connected on one side by a convexoconcave curved portion 32 to a cylindrical surface 33 which is adjacent to the second threaded portion 18b, and connected on the other side by another convexo-concave curved portion 34 to another cylindrical surface 35 adjacent to the male abutment shoulder 22. The cylindrical surface 35 is connected to the male abutment shoulder 22 by a blending radius 36. The convexo-concave curved parts 32 and 34 are arranged in such a way that they arc convex on the side adjacent to the male intennediate seaiing surface 27, and concave when they connect respectively to the cylindrical surfaces to which they are respectively adjacent. In practice, the convexo-concave curved parts 32 and 34 are such that the outer diameter at the level of the cylindrical surface 33 adjacent to the threaded portion 18b is greater than that of the cylindrical surface 35 adjacent to the male abutment 22.

Similarly, the female intermediate sealing surface 28 is connected on one side by a convexo-concave curved portion 37 to a cylindrical surface 38 which is adjacent to the second female threaded portion 16b, and connected on the other side by another convexoconcave curved portion 39 to another cylindrical surface 40 adjacent to the female abutment shoulder 24. The convexo-concave curved parts 37 and 39 are arranged in such a way that they are convex on the side adjacent to the female intermediate sealing surface 28, and concave when they connect respectively to the cylindrical surfaces to which they are respectively adjacent. Tn practice, the convexo-concave curved parts 37 and 39 are such that the inner diameter ai the level of the cylindrical surface 38 adjacent to the female threaded portion 14b is greater than that of the cylindncal surface 40 adjacent to the female abutment 24.

The convexo-concave surfaces 32, 34, 37 and 39 are connected tangentially. The convexo-concave surfaces 32, 34, 37 and 39 comprise curved parts connected tangentially to one another, having a curving radius comprised between 3 and 30 mm.

More specifically, lhe cylindrical surface 40 is connected to the female abutment shoulder 24 by a concave transition 41. The concave transition 4 i has a frustoconical part connected tangentially to a curving radius less than 1 mm, the curving radius of the concave transition 41 being tangent to the female abutment shoulder 42, in order to avoid the concentration of stresses in proximity to the female abutment shoulder 24.

In order to avoid the concentration of stresses in proximity' to the male abutment shoulder 22, the male abutment shoulder is connected by a large-radius concave transition 42 to a cylindrical surface 43 adjacent to an end of the first male threaded portion 18a.

Similarly, the female abutment shoulder 24 is connected by a biending radius 44 to an adjacent cylindrical surface 45 of the first female threaded portion 16a. In practice, given the respectively male and female threaded portions are obtained by machining, the cylindrical surface 45 is adjacent to a groove 46 having a cylindrical bottom for the extraction of the tool for machining the thread of the fîrst female threaded portion 16a. The cylindncal-bottom groove having a cylindrical bottom 46 défîmes an inner diameter greater than the inner diameter of the cylindrical surface 45. The groove 46 comprises a frustoconical surface linking to the cylindrical surface 45.

In detail, in Figures 8 and 9, according to an embodiment of the invention, the inner seal is of the torus-to-cone type. In this example, the male inner sealing surface 25 is frustoconical and the female inner sealing surface 26 is toroid. In Figure 8, the femaie limer sealing surface 26 is a curve obtained by several adjacent convex curved portions tangential to one another. In an example, it comprises two adjacent curved portions, respectîvely radii RI and R2, such that the curved portion RI is closerto the tube body 140 than the curved portion R2, and the radius RI is shorter than the radius R2. Preferably, the radii RI and R2 are greater than 30 mm. This toroid female inner sealing surface 26 is connected, on the side of the tube body 140, to a cylindrical surface 47 by a curving radius 48 having a radius at least 3 times shorter dian the radii RI and R2. On the opposite side, it is connected to an adjacent cylindrical surface 50 of the first female threaded portion 16aby a convexo-concave 10 surface which is connected tangentially on the one hand to the cylindrical surface 50, and on the other hand to the sealing surface 26.

In order to corne into contact with the female inner sealing surface 26, the male inner sealing surface 25 comprises a frustoconical portion having a taper compnsed between 10 and 20%. At the level of the inner perimeter of the male tool joint 12, the inner surface of the 15 male tool joint is chamfered 51, so that the inner non-threaded portion 30 has a smaher thickness, and even if the inner seal induces an internai deflection of the sealing ring defined between the inner sealing surface 25 and the free end 19, the male tool joint 18 does not substantially modify the inner passage diameter, called connection drift diameter.

The male inner sealing surface 25 is connected tangentially to a convex surface 52, 20 having a large curving radius, which is itself connected by an interface 53 at the free edge 19 which is defined perpendicularly tothe axis X. On the side opposite to the free edge 19, the male sealing surface is connected tangentially to a cylindrical surface 54 upstream of the start of the tlireading of the first male threaded portion 18a. This cylindrical surface 54 allows the tools for machining the thread to start.

The main radius R2 is determined in order to overcome the stress, and the plastrcizing ofthe female tooljoint 16 above the inner seal. This radius R2 is thus intended to manage the sealing for the loading where the contact pressure is very high. When the contact pressure is more moderato, the deflection of the sealing ring of the male tool joint is also more moderate, and the position of the sealing point thus moves towards the inside of the tube body 140 so that the value of tire radius R2 is no longer necessary. A radius RI less than the radius R2 is thus used for these working points. The radial thickness of the sealing surface along the axis X is such that it makes it possible to use a smaller thickness in order to machine this female inner sealing surface 26. Therefore, the machining of the female tool joint can be carried out on tubes, regardless of their outer diameter, and automatically the effectiveness of the female tool joint is increased for a given tube thickness. A curving radius 48 also makes it possible to reduce the quantity of thickness of material necessaty for machining the female tool joint, and thus to increase the effectiveness of the connection for a given tube thickness.

During makeup, the first contact of the male inner sealing surface 25 is made with the radius portion R2. As this first contact can be barsh. the fact of having an increased R2 value makes it possible to limit the risk of galling. Once the contact has been established, the remainder of the makeup is completed by moving the contact between the male inner sealing surface 25 to the radius portion RI. This spécifie configuration of the female inner sealing surface 26 to improve the performance and the number of makeup-breakouts that the connection according to the invention can beat.

In the remainder of the description, we will now describe the threadings.

In the embodiment shown in Figures 1 to 9, ail of the male threaded portions 18a, 18b and female threaded portions 16a and 16b respectively each comprise a single hélix.

However in a variant, while remaining within the scope of the invention, a male threaded portion and its complementary threaded portion can comprise one and the same number of hélices greater than 2 helices.

A hélix is defined by a helical protubérance. A hélix comprises a load flank, a thread crest, a stabbing flank and a thread root. The thread root, like the thread crest, is defined between a load flank and a stabbing flank, such that

- on a hélix borne by the male tool joint 18, the thread root is radially doser to the longitudinal axis X than the thread crest;

- on a hélix borne by the female tool joint 16, the thread root of this hélix is radially further from the longitudinal axis X than the thread crest.

A longitudinal cross-section profile of this helical protubérance is said to be substantially trapézoïdal, insofar as a thread crest extends axially between the load flank and stabbing flank respectively.

Figure 10 represents a frustoconical portion 74 on two tums ofthe hélix ofthe first and ofthe second male threaded portion 18a, respectively 18b. The structure described below for the hélix is reproduced over at least several tums, over at least 3 tums, while maintaining the dimensions, shapes and proportions set out below.

The hélix of the male threaded portion comprises a load flank LFp, a thread crest 60, a stabbing flank SFp and a thread root 61. The root 60 and the crest 61 form segments parallel to the longitudinal axis X. The thread root 61 is connected by a concave curved transition 62 to the stabbing flank SFp, The concave curved transition 62 is such that the thread root 61 and the stabbing flank SFp form an angle greater than 90°. The stabbing flank SFp is rectilinear, and fonns an angle 63 with respect to a normal N to the longitudinal axis X. The thread root 61 is connected by a second concave curved transition 64 to the load flank LFp, at an end of the thread root 6] opposite to that by which this thread root is connected to the stabbing flank SFp. The second concave curved transition 64 is such that the thread root 61 and the load flank LFp form an angle less than 90°. The load flank LFp is rectilinear, and forms an angle 65 with respect to the normal N to the longitudinal axis X.

The angle 65 is equal to the angle 63 plus or minus machining tolérances, namely +/0.25°. The stabbing flanks SFp are chosen parallel to the load flanks LFp so that the stabbing flanks take up a part of the load observed in the connection under certain compressive stresses.

The angle 63 is for example comprised between 1 and 5°, preferably between i .25 and 3.75°.

In more detail, in Figure 11, the curved transition 62 is controlled in order to be able to guarantee the radial dimension of tire stabbing flank SFp. However, the thread root 61 can comprise a step with two staggered cylindrical portions 61a and 61b, so that the cylindncal portion 61a immediately adjacent to the curved transition 62 is radially further from the longitudinal axis X than the cylindrical portion 61b adjacent to the load flank LFp.

The crest 60 is connected to the stabbing flank SFp by a convex curved transition 66. This crest 60 is connected to the load flank LFp by a complex convex surface 67 comprising a frustoconical portion 68 adjacent to the cylindrical portion of the crest 60, this frustoconical portion 68 being connected by a curving radius 69 to the load flank LFp.

The radial height of the stabbing flank SFp is greater than the radial height of the load flank LFp, so that the male threaded portion comprises a frustoconical portion in the direction in which a fictitious line PL (pitch line) passing through the centre of the successive stabbing flanks SFp and load flanks LFp of the hélix defines a taper angle 70 with respect to the longitudinal axis X. In this frustoconical portion, the hélix is defîned between the surfaces of two fictitious frustoconical envelope surfaces 71 and 72 respectîvely parallel to the pitch line PL. The fictitious lorver envelope surface 71 passes through the tangent points between the thread root 61 and the curved transition 62 adjacent to the stabbing flank SFp, of each tum ofthe hélix in this frustoconical portion. The fictitious upper envelope surface 72 passes through a tangent point between the convex curved transition 66 adjacent to the stabbing flank SFp and the thread crest 60.

The angle 70 is such that the taper of this maie threaded portion 18a and/or 18b is comprised between 5 and 15%, preferably between 8 and 12%.

The hélix comprises, in addition to tire frustoconical portion 74 described above, a cylindrical portion 73 at an end of the hélix, this cylindrical portion 73 developing over more than one tum, and preferably less than three tnms, in particular less than two tums. In tire embodiment described, this end of the hélix having a cylindrical shape 73 is placed on the side of the end of the male threaded portion that is closest axraliy to the free edge 19. In particular, tire first male threaded portion 18a and the second male threaded portion 18b each comprise such a cylindrical portion 73 adjacent to the frustoconical portion 74 of the hélix.

The cylindrical portion 73 of the hélix is such that the successive roots 61 of this cylindrical portion are parallel and collinear to one another. The fictitious lower envclope surface 71 becomes parallel to the axis X in this cylindrical portion, whiie the fictitious upper enveiope surface 72 maintains the saine taper for the frustoconical part 74 and the cylindrical part 73.

The hélix of the male threaded portion comprises in addition an imperfect portion 75 at an opposite end of the male threaded portion, namely at an end of the hélix that is furthest axially from the free edge 19. In particular, the first male threaded portion 18a and the second female threaded portion 18b each comprise such an imperfect portion 75 adjacent to the frustoconical portion 74, the frustoconical portion 74 being flanked between the imperfect portion 75 and the cylindrical portion 73. This imperfect portion 75 is such that the threads are of smaller heights, and the successive crests 60 of this imperfect portion 75 arc parallel and collinear to one another. The fictitious upper enveiope surface 72 becomes parallel to the axis X in this imperfect portion 75, This imperfect portion 75 develops over more than one tum, and preferably less than three tums, in particular less than two tums. In the imperfect portion 75, the fictitious lower enveiope surface 7] has a taper identical to that observed in the frustoconical portion 74.

The existence ofthe cylindrical portion 73 makes it possible to limit tire radial bulk of the male threaded portion in the thickness of the wall where the male tool joint is formed. Consequently, a greater minimal thickness can be guaranteed at the level of tire respectively inner 25 and intermediate 27 male sealing surfaces. Tire sealing performance is improved by this configuration of the male threaded portion.

In addition, the presence of the cylindrical portion 73 adjacent to the frustoconical portion 74 makes it possible to avoid any sudden variation in the stiffiiess of the male non threaded inner portion 30. This configuration makes it possible to avoid an early plastification ofthe zones ofthe connection receiving a maximum of stresses.

The hélix ofthe male threaded portion is such that a pitch ofthe stabbing flank SFLp is constant in the frustoconical portion 74, and also constant in the imperfect portion 75. The pitch is in particular the same in the frustoconical 74 and imperfect 75 portions. A pitch of the stabbing flank LFLp is the same in the frustoconical 74 and imperfect 75 portions, this pitch LFLp also being equal to the pitch of the stabbing flank SFLp.

The pitch ofthe stabbing flank SFLpl and the pitch ofthe ioad flank LFLpl are equal to a constant kl for the first male threaded portion 18a. Similariy, for the second male threaded portion 18b, the pitch of the stabbing flank SFLp2 and the pitch of the load flank LFLp2 are equal to this same constant kl. According to the invention, this constant kl is for exampie comprised between 5 and 20 mm, preferably between 6 and 8 mm.

Preferably, a tooth width Wtp of the male threaded portion, defined as a measurement along the longitudinal axis X, of the distance between the stabbing flank SFp and the load flank LFp, at the points of intersection with the pitch Ime PL, is such that this tooth has a width less than half of the constant k 1, in particular less than 40% of the value kl.

Figure 12 shows a frustoconical portion 94 over two tums of the hélix of the first and the second female threaded portion 16a, respectively 16b. Oie structure described below for the hélix is reproduced over at least several tums, over at least 3 tums, while maintaining the dimensions, shapes and proportions set out below.

The hélix of the female threaded portion comprises a load flank LFb, a thread crest 80, a stabbing flank SFb and a thread root 81. The root 80 and the crest 81 fonn segments parallel to the longitudinal axis X. The thread root 81 is connected by a concave curved transition 82 to the stabbing flank SFb, The concave curved transition 82 is such that the thread root 81 and the stabbing flank SFb form an angle greater than 90°. In an identical manner to that at the level of the male thread root 61, the thread root 81 can comprise a step with two staggered cylindrical portions 81a and 81b, so that the cylindrical portion 81a immediately adjacent to the concave curved transition 82 is radially doser to the longitudinal axis X than the cylindrical portion 81b of this root 81 which is adjacent to the load flank LFp.

The stabbing flank SFp is rectilinear, and fonns an angle 83 with respect to a normal N to the longitudinal axis X. The thread root 81 is connected by a second concave curved transition 84 to the load flank LFb, at an end of the thread root 81 opposite to that by which this thread root is connected to the stabbing flank SFb. The second concave curved transition 84 is such that the thread root 81 and the load flank LFb form an angle less than 90°. The load flank LFb is rectilinear, and forms an angle 85 with respect to the normal N to the longitudinal axis X.

The angle 85 is equal to the angle 83 plus or minus machining tolérances, namely +/0.25°.

The angle 85 is equal to the angle 65 plus or minus machining tolérances, namely +/0.25°,

The angle 83 is equal to the angle 63 plus or minus machining tolérances, namely +10.25°.

The angle 83 is for example comprised between 1 and 5°, preferably between 1,25 and 3.75°,

In more detail in Figure 13, the crest 80 is connected to the stabbing flank SFb by a convex curved transition 86. The curved transition 86 comprises a tangential blending radius 86a with the stabbing flank SFb, a tangential blending radius 86c with the crest 80, and a frustoconical surface 86b tangentially connected on either side to the tangential connections 86a and 86c. The frustoconical surface 86b forms an obtuse angle 86d, for example an open angle comprised between 190° and 240°, preferably ofthe order of 225° with respect to the stabbing flank SFb, The frustoconical surface 86b forms achamfer facilitating the insertion of the male tool joint mto the femaie tool joint, This frustoconical surface 86b reduces the axial width of the crest 80 so that an additional volume is defined between this frustoconical surface 86b and the complementary' profile of the male threaded portion, this volume also making it possible to contribute to the réduction in the pressure of grease in the threading.

This crest 80 is connected to the load flank LFb by a complex convex surface 87 comprising a frustoconical portion 88 adjacent to the cylindrical portion of the crest 80, this frustoconical portion 88 being connected by a curving radius 89 to the load flank LFb.

The radial height of the load flank LFb is greater than the radial height ofthe stabbing flank SFb, so that the femaie threaded portion comprises a frustoconical portion in the direction in which a fictitious line PL (pitch line) passing through the centre ofthe successive stabbing flanks SFb and load flanks LFb of the hélix defines a taper angle 90 with respect to the longitudinal axis X.

The taper of this fictitious line is the same as that defined by the frustoconical portion 75 ofthe male threaded portion, these lines PL being superimposed in the assembied position of the connection as can be seen in Figure 14.

In this frustoconical portion 94 of the female threaded portion, the hélix is defined between the surfaces oftwo fictitious frustoconical envelope surfaces 91 and 92 respectively parallel to the pitch line PL. The fictitious upper envelope surface 91 passes through the tangent points between the thread root 81 and the curved transition 82 adjacent to the stabbing flank SFb, of each tum of the hélix in this frustoconical portion 94. The fictitious upper envelope surface 92 passes through a tangent point between the convex curved transition 86 adjacent to the stabbing flank SFb and the thread crest 80.

The angle 90 is such that the taper of this female threaded portion 16a and/or 16b is comprised between 5 and 15%, preferably between 8 and 12%.

The hélix comprises, in addition to the frustoconical portion 94 described above, an imperfect portion at an end of the hélix, this imperfect portion 95 developing over more than one tum, and preferably less than three tums, in particular less than two tums. In the embodiment described, this end ofthe hélix is placed on the side ofthe end of the female threaded portion that is furthest axially from the free edge 17 ofthe female tooljoint. In particular, the first female threaded portion 16a and the second female threaded portion 16b each comprise such an imperfect portion 95 adjacent to the frustoconical portion 94 of the hélix.

The imperfect portion 95 is such that the threads are of smalier heights, and the successive crests 80 ofthis imperfect portion 95 are parallel and collinearto one another. The fictitious lower envelope surface 92 becomes parallel to the axis X in this imperfect portion 95. In the imperfect portion 95, the fictitious upper envelope surface 91 has a taper identical to that observed in the frustoconical portion 94.

In the assembled position of the male tool joint with the female tool joint, the imperfect portion 95 of a female threaded portion is engaged with the cylindrical portion 73 ofthe corresponding male threaded portion.

In the embodiment according to the invention, the frustoconical portion 94 ofthe female threaded portion comprises more spires than the frustoconical portion 74 of the male threaded portion. In fact, the imperfect portion 75 of the male threaded portion is engaged in the frustoconical portion ofthe female threaded portion in the assembled position ofthe connection.

In particular, the male threaded portion 18a can comprise more spires than the second male threaded portion 18b.

In particular, the first female threaded portion 16a can comprise more spires than the second female threaded portion 16b.

In partîcular, the frustoconical portion 74 of the first male threaded portion 18a can comprise more spires than the frustoconical portion 74 of the second male threaded portion 18b.

In partîcular, the frustoconical portion 94 of the first female threaded portion 16a can 5 compose more spires than the frustoconical portion 94 of the second female threaded portion 16b.

The hélix of the female threaded portion is such that a pitch of the stabbing flank SFLb is constant in the frustoconical portion 94, and also constant in the imperfect portion 95. The pitch is in partîcular the same in the frustoconical 94 and imperfect 95 portions. A 10 pitch of the stabbing flank LFLb is the same in the frustoconical 94 and imperfect 95 portions, this pitch LFLb also being equal to the pitch of the stabbing flank SFLb.

The pitch of the stabbing flank SFLb 1 and the pitch of the load flank LFLb 1 are equal to the constant k2 for the first female threaded portion 16a. Similarly, for the second female threaded portion 16b, the pitch of the stabbing flank SFLb2 and the pitch of the load 15 flank LFLb2 are equal to this same constant k2.

According to the invention, the constants kl and k2 are equal to one another, and they can also be denoted under the constant tenn k. Given the machining tolérances, within the meaning of the invention kl is equal to k2 +/- 0.05 mm.

Preferably, a tooth width Wtb of the female threaded portion, defined as a measurement along the longitudinal axis X, of the distance between the stabbing flank SFb and the load flank LFb, at the points of intersection with the pitch Ime PL, is such that this tooth has a width greater than the width of the tooth Wtp of the frustoconical portion 74 of the male threaded portion.

In practice, according to the invention, and in the example shown, the importance of 25 defining the teeth of the male threaded portions having a width less than the teeth of the female threaded portions. For example, in the embodiment shown, [Math 9J 50% < ^ < 80% wtb

And

[Math 10]

Wtp + Wtb < k

Preferably,

[Math 11]

Wtp ^5S%<WTb^<7™ Or even

[Math 12]

W tp ⁶⁷°^A<wâ^<73%

As the teeth of the female threaded portion are larger than the teeth of the male threaded portion, the female teeth thus hâve less of a tendency to plasticize. Now in a connection according to the invention, the stresses are seen more clearly in a zone 99 extending between tire first teeth engaged on the side of the inner sealing surfaces 25 and 26, and said sealing surfaces (see Figure 5).

Maximum shear lines which can be modelled in a connection according to the invention under compressive ioading are shown at 45° with respect to the crest 60, on the side where this crest is connected to the stabbing flank SFp. And conversely, maximum shear fines which can be modelled in a connection according to the invention under tensile Ioading are shown at 45° with respect to the crest 60, on the side where this crest is connected to the load flank LFp, Tire intersection between these modelled shear lines makes it possible to define a triangle of the maximum stresses above each crest of the male threaded portion. These triangles localize the zones where the risks of plasticizing insidc the female tool joint are maximum. The inventors hâve discovered that in order to maintain the effectivencss of the connection, it is essential to limit the height of these triangles, thus to choose a ratio as claimed in order to limit the plasticizing in the female tool joint which has a restricted thickness due to the intégral connection design.

In the assembled position, as shown in Figure 14, the load flanks LFp and LFb are in contact, an axial play 100 is maintained between the stabbing flanks SFp and SFb. Similarly, a radial play 101 is maintained between the crests 60 ofthe male threaded portion and the roots 81 ofthe female threaded portion, while the fictitious lines 71 and 91 are superimposed insofar as the crest 80 of the female threaded portion cornes into contact with the thread root 61 of the male threaded portion.

The radial play 101 also makes it possible to limit the dimensioning ofthe zones of maximum stresses in the female tool joint.

For example, the plays 100 and 101 are comprised between 0.1 mm and 0.5 mm, preferably between 0.2 and 0.3 mm. With such an axial play, the tooth widths fiilfil the condition below;

[Math 13]

Wtp + Wtb <k-0.1mm

As the male threaded portion is cylindrical -conical, little free volume remains between the helices of the assembled male and female threaded portions. When the connection according to the invention is used with application of a makeup grease applied on the male and female tool joint before the assembly thereof, there is little space available in order to avoid the increase in pressure of the grease inside the connection. According to the invention, in the female threaded portion, and in particular in the first female threaded portion 16a an annular groove 110 is provided in order to make it possible to receive the excess grease which flows back. The benefit of this groove is to allow the grease to accumulate locally during the makeup or during the use of the connection under certain température and pressure conditions. This annular groove is provided in the female threaded portion which is arranged between two sealing surfaces.

In the embodiment shown, without a seal between the free edge 17 of the female tool joint and the second female threaded portion, an annular groove is not provided in the second female threaded portion.

In Figure 15, the annular groove 110 is defined between the fictitious inner 92 and outer 91 lines. For example, the annular groove 110 has an axial width G of the order of the constant k. The groove 110 comprises a frustoconical root 111, having a taper identical to that of the female threaded portion. The annular groove is asymmetrical. On one side ofthe root 111, on the side of the inner sealing surface 26, the root 111 is connected to a rectilinear part 112 which has an angle 113 with the normal N comprised between 10 and 30°. On an opposite side of the root 111, on the side of the intermediate sealing surface 28, the root 111 is connected to another rectilinear part 114 which has an angle 115 with the normal N comprised between 30 and 85°.

This groove makes it possible for the grease to degas without creating a temporary loss of the seal, or risking local plasticizing of the connection, while the connection is placed ai aven,' great dcpth and subjected to températures ofthe order of 180°C.

The invention also applies to threaded connections between a male tool joint comprising a single threaded portion, and a female tool joint also comprising a single threaded portion. These connections according to the invention (not shown) can comprise one or two metal-mctal seals, and also an axial abutment.

The invention also applies to threaded coupled connections.

Claims (16)

1. [Claim 1] Threaded tubular connection for the drilling and/or exploitation of hydrocarbon wells, comprising a first tube (12) equipped at a first distal end with a male tool joint (18) and a second tube (14) equipped at a second distal end with a female tool joint (16), the male tool joint (18) being capable of being assembled by makeup with the female tool joint (16), the first tube (12) assembled to the second tube (14) together define a longitudinal axis, the male tool joint (18) comprising a male threaded portion (I8a, 18b), the female tool joint (16) comprising a female threaded portion (16a, 16b) engaged with the male threaded portion when the connection is assembled, tire male and female threaded portions each comprising at least one hélix equipped with a load flank, a thread crest, a stabbing flank, a thread root, such that a pitch of the load flank LFLp and a pitch of the stabbing flank SFLp of the male threaded portion, and respectively a pitch of the load flank LFLb and a pitch of the stabbing flank SFLb of the female threaded portion fulfil the following condition, for at least two consecutive tums ofthe respective helices of the male and female threaded portions: [Math 14]

   SFLp - LFLp = SFLb - LFLb = k and such that along the longitudinal axis, in these at least two consecutive tums, a tooth width (Wtp) of the hélix of the male threaded portion (18a, 18b) and a tooth width (Wtb) of the hélix of the corresponding female threaded portion (18a, 18b) are such that |Math 15]

   Wtp

   50% < < ^80%

   W tb

   Or |Math 16]

   50% <

   Wtb

   Wtp

   80%

   And

   [Math 17]

   Wtp + Wtb < k

   [Claim 2[ Threaded tubular connection according to claim 1, characterized in that the mathematical condition set out below is satisfied [Math 181

   Wtp 55% < < 75%

   Wtb
2. [Claim 3] Threaded tubular connection according to claim 1 or 2, characterized in that the mathematical condition set out below is satisfied

   [Math 19]

   Wtp ⁶™<wr_b ^<73%
3. [Claim 4] Threaded tubular connection according to any one of the preceding claims, characterized in that the tooth width (Wtp) of the hélix of the male threaded portion (18a, 18b) is comprised between 2,5 and 3,5 mm.
4. [Claim 5] Threaded tubular connection according to any one of the preceding claims, characterized in that the tooth width (Wtb) of the hélix of the female threaded portion (16a, 16b) is comprised between 3.7 and 4.5 mm.
5. [Claim 6] Threaded tubular connection according to any one of the preceding claims, characterized m that the tooth widths (Wtp, Wtb) of the helices of the male threaded portion (18a, 18b) and respectively female threaded (16a, 16b) portions failli the following condition: [Math 20]

   Wtp + Wtb < k — 0.1 mm over said at least two consecutive tums of these helices,
6. [Claim 7] Threaded tubular connection according to any one of the preceding claims, characterized in that the tooth widths of the complété helices of the male threaded portions (18a, 18b) and respectively female threaded portions (16a, 16b) fulfil the following condition: for each tum (n), atooth width ofthe male threading (Wtp n) and a tooth width of the female threading (Wtb n) are such that for each n:

   [Math 21]

   Wtpn + Wtbn < k — 0.1 mm
7. [Claim 8] Threaded tubular connection according to any one of the preceding claims. characterized in that a part of the stabbing flank is parallel to a part of the load flank, with a tolérance of +/- 0.25° in the inclination of these parts relative to the longitudinal axis.
8. [Claim 9] Threaded tubular connection according to any one of the preceding claims, characterized in that the stabbing flank and the load flank of the hélix of the maie threaded portion (18a, 18b) are respectively rectilinear, and respectively connected by blending radii (62, 64, 66, 68) to the adjacent thread crest (60) and thread root (61).
9. [Claim 10] Threaded tubular connection according to any one of the preceding claims, characterized in that the stabbing flank (SFb) of the hélix of the female threaded portion comprises a rectilinear segment connected to the thread crest (80) by a segment that is inclined with respect to the stabbing flank so as to propose a convexity, such that these two segments form between them an obtuse angle (86d) comprised between 190° and 260°, for cxample ofthe order of 225°.

   [Claim l IJ Threaded tubular connection according to any one of the preceding claims, characterized in that the thread root (61) ofthe hélix ofthe male threaded portion (18a, 18b) comprises two segments (61a, 61b), a first male thread root segment (61a) situated on the side of the stabbing flank and a second male thread root segment (61b) situated on the side of the load flank, and such that a radial distance of the first male thread root segment is equal to or greater than the radial distance of the second male thread root segment, the radial distances being evaluated relative to a thread crest (6à) adjacent to said thread root (61) of the hélix of the male threaded portion.
10. [Claim 12] Threaded tubular connection according to any one of the preceding claims, characterized in that the load flank of the hélix of tire male threaded portion (18a, 18b) forms an angle comprised between 1° and 5°, preferably between 1.25 and 3.75° with respect to a normal to the longitudinal axis, and is parallel to the load flank of the hélix of the female threaded portion (16a, 16b), with a tolérance of +/- 0.25° in tire inclination of these load flanks with respect to the longitudinal axis.
11. [Claim 13] Threaded tubular connection according to any one of the preceding claims, characterized in that the load flank of the hélix of the male threaded portion (18a, 18b) forms with an adjacent thread root of this hélix an angle less than or equal to 90°.
12. [Claim 14] Threaded tubular connection according to any one of the preceding claims, characterized in that the hélix of the female threaded portion (16a, 16b) is fnistoconical, preferably exclusively frustoconical, for exampie having a taper compriscd between 5% and 15%, preferentially 8% and 12%.
13. [Claim 15] Threaded tubular connection according to the preceding claim, characterized in that the hélix of the male threaded portion (18a, 18b) comprises at least a frustoconical part having a taper identical to that of the hélix of the female threaded portion (16a, 16b).

    [ Claim 16] Threaded tubular connection according to any one of the preceding claims, characterized in that the pitch of the load flank LFLp and the pitch of the stabbing flank SFLp are comprised between 5 and 20 mm, preferentially between 6 and 8 mm.
14. [Claim 17] Threaded tubular connection according to the preceding claim, characterized m that the male threaded portion (18a, 18b), and respectively the female threaded portion (16a, 16b) each comprise a single hélix.

    [Claim 18 [ Threaded tubular connection according to the preceding claim, characterized in that the helices of the male threaded portion (18a, 18b) and respectively the female threaded portion (16a, 16b) comprise at least 3 tums, preferably at least 4 tums.
15. [Claim 19] Threaded tubular connection according to the preceding claim, characterized in that the tlircad crests and the thread roots of the male and female threaded portions hâve a taper less than the taper of said threaded portions, for example these thread crests and these thread roots being parallel to the longitudinal axis.
16. [Claim 20] Threaded tubular connection according to the preceding claim, characterized in that a radial height of a stabbing flank of the male threaded portion (18a, 18b) is greater than a radial height of a load flank of this male threaded portion.