THREADED JOINT WITH ASYMMETRICAL HELICAL PROFILE

Abstract

A tubular threaded joint for the casing of hydrocarbon wells obtained by threading a male connector with a female connector, wherein the joint consists of a threaded portion (16a, 18a), such that the male and respective female threaded portions each consist of a helix provided with a carrier side, a thread vertex, an engagement side, and a thread root, such that a pitch of the carrier side (LFLp, LFLb) and a pitch of the engagement side (SFLp, SFLb) satisfy the following condition [Math 22] SFLb = LFLb = LFLp = k, a tooth width (Wtp) of the male helix and a tooth width of the female helix (Wtb) are such that [Math 23] 50% < (see Formula) < 80% or [Math 24] 50% < (see Formula) < 80% and [Math 25] Wtp + Wtb < k.

Description

THREADED JOINT WITH ASYMMETRICAL HELICAL PROFILE DESCRIPTIVE MEMORANDUM The present invention relates to pipe joints or assemblies intended for connection by means of threading and concerns pipes used in industry, and in particular threaded assemblies or joints intended to equip production tubing strings or production tubing fittings, or casing strings for the exploration, prospecting, or exploitation of oil or gas wells, as well as threaded assemblies or joints used for any application where it may be necessary to assemble tubing strings or tubing fittings, such as in the geothermal or steam production industries. The threaded assembly according to the invention is particularly useful for assembling metal pipes used for casing oil or gas wells, as explained below. In this text, the words assembly, joint, union, or connection are used interchangeably, except in specific contexts. "Tubes" refers to all types of tubes, tubular components, or tubular fittings existing or potentially applicable in industry, and these tubes are generally metallic. In particular, these tubes are seamless tubes made from steel, such as those defined in API 5 CT or ISO 11960:2004. Preferably, a joint according to the invention is formed between tubes made of a material with high tensile strength, such as steels with a tensile strength between 862 and 965 MPa (125 to 140 ksi). Numerous types of pipe assemblies for oil and gas pipelines are known to provide satisfactory results in terms of mechanical properties and sealing, even under severe operating conditions. Some of these assemblies utilize pipes with male tapered threads at both ends, which are joined by means of sleeves with two corresponding female tapered threads. This assembly method has the advantage of rigidifying both components due to the positive interference created between the male and female threads. These are referred to as threaded assembly joints, also known as T&C joints. However, the outside diameter of these sleeves is larger than that of the corresponding pipes and, when these assemblies are used in casing, requires drilling holes of increased diameter. In the case of very deep wells, exceeding 4000 m in depth, where the casing must be lowered further into the well, sleeveless assemblies, such as the ML / a / ZUZZ / UUU 104 disclosed in documents US-2992019, EP-0767335 or even US-2013 / 0015657. In this case, each of the tubes consists of one end provided with a male connector and a second end provided with a female connector. The tubes are assembled end-to-end by the joints between the male and female connectors. These assemblies are designated as integrals. To meet the increased need for resistance to internal and external pressures, US-4662659 discloses an integral gasket provided with two stepped threaded portions on one side and an intermediate stop on the other. This intermediate stop is designed with a negative angle to increase pressure resistance. Furthermore, on one side of this intermediate stop, or on either side of it, the document discloses radial interference seal zones between tapered surfaces whose taper angles are slightly modified relative to each other by an angle of θ. According to this document, the seal is ensured exclusively at the central level, between the two threaded portions, in the vicinity of the intermediate stop.Document US-2019-0040978 proposes an alternative to document US-4662659, specifying a particular geometry of these seals on one side and the other of the intermediate stop, and modifying the shape of the threading and choosing a dovetail profile threading. On the other hand, document US-2017-0101830 discloses another joint provided with two stepped threaded portions on one side and an intermediate stop on the other. According to this document, a seal is provided between one threaded portion and this intermediate stop. However, defining this seal reduces the performance and capacity of the intermediate stop, so this document discloses providing an additional stop surface at the distal end of the male connector. Alternatively, other documents propose modifying the threading to compensate for the reduced compression performance of the intermediate stop. These alternative threadings are then called dovetail threads and are threaded in such a way as to achieve a locking effect between the threaded portions.For this purpose, the threaded portions are designed with different pitch values ​​for the bearing side and the mating side. The helix of this threading has a tooth width that increases with each turn of the helix from one end to the other, while the gaps between the turns of this helix decrease in the same proportion. In this way, the threaded portions are threaded until contact is achieved between the mating sides, but also between the bearing sides. This type of joint, called a 'self-locking wedge thread', while very effective, is nevertheless very difficult to manufacture and master during assembly. Despite the various solutions already known, a need arose to facilitate the manufacture of an integral connection suitable for forming casings for deep wells, where resistance to internal and external pressure cycles, as well as tensile and compressive tolerances, is achieved while accepting the manufacturing and assembly tolerances inherent in the world of oil and gas pipes. In practice, it has also appeared that the method of applying assembly grease to the connections is a primary factor in the success of a joint. The threaded joint according to the invention allows for better tolerance of maintenance variations during grease application. The aim of the invention is to provide an integral joint that meets technical requirements similar to those of sleeve joints, while achieving an efficiency close to that of the tube. Specifically, a joint according to the invention can have an efficiency equal to 96% of the tube's efficiency. Efficiency is generally defined as the ratio of the critical cross-section of the joint to the cross-section of a typical section of tube between the two ends of a component. The critical cross-section of the joint is equal to the smallest critical cross-section of the male or female connector. The invention is preferably applicable to large diameter threaded joints, in particular to tubes with an outside diameter greater than 177.8 mm (7 inches), preferably greater than 254 mm (10 inches), for example 406.4 mm (16 inches). The invention proposes a joint with improved resistance in these aspects. The invention relates to a tubular threaded joint for drilling or exploiting hydrocarbon wells, comprising a first tube provided at a first distal end with a male connector and a second tube provided at a second distal end with a female connector, wherein the male connector is suitable for assembly by threading with the female connector, the first tube assembled to the second tube together defining a longitudinal axis, wherein the male connector consists of a male threaded portion, wherein the female connector consists of a female threaded portion engaged with the male threaded portion when the joint is assembled, wherein each of the male and female threaded portions consists of at least one helix provided with a carrier side, a thread vertex, an engagement side, and a thread root, such as a carrier side pitch LFLp and an engagement side pitch SFLp of the male threaded portion.and respectively a pitch on the carrier side LFLb and a pitch on the engagement side SFLb of the female threaded portion meet the following condition, for at least two consecutive turns of the respective helices of the male and female threaded portions:, [Math 1] SFLp = LFLp = SFLb = LFLb = ky such that along the longitudinal axis, in these at least two consecutive turns, a helix tooth width (Wtp) of the male threaded portion and a helix tooth width of the corresponding female threaded portion (Wtb) are such that [Math 2] Wtp 50% < 777-7 < 80% Wtb EITHER [Math 3] 50% < — < 80% Wtp AND [Math 4] Wtp + Wtb < k Ideally, the board can meet the following condition [Math 5] W tp 55% < <75% Wtb Even the following condition [Math 6] Wtp 67% < 777T <73% Wtb The helix width of the male threaded portion can range from 2.5 to 3.5 mm. And, for example, the helix width of the female threaded portion can range from 3.7 to 4.5 mm. Preferably, the helix tooth widths of the male and female threaded portions can meet the following condition: [Math 7] Wtp + Wtb < k - 0.1 mm in the aforementioned at least two consecutive turns of these propellers, so that these at least two turns may not be self-locking. The tooth widths of the complete helices of the male and female threaded portions can satisfy the following condition: for each turn (n), a tooth width of the male thread (Wtp / 7) and a tooth width of the female thread (Wtb / 7) are such that for all n: [Math 8] Wtpn + Wtbn < k - 0.1 mm Advantageously, a portion of the coupling side can be parallel to a portion of the carrier side, with a tolerance of + / - 0.25° in the inclination of these portions relative to the longitudinal axis. The coupling sides can thus contribute to the recoil of compressive forces. The engagement side and the helix-bearing side of the male threaded portion can be straight and joined by radii to the adjacent thread crest and root. In this case, the engagement side of the helix of the female threaded portion can also consist of a straight segment joined to the thread crest by a segment inclined relative to the engagement side to create a convexity, such that these two segments form an obtuse angle (86d) between them of between 190° and 260°, for example, on the order of 225°. This convexity ensures the absence of contact with the root portion 61 and the concave radial joint 62. The thread root of the helix of the male threaded portion may comprise two segments, a first male thread root segment located on the side of the engagement side and a second male thread root segment located on the side of the carrier side, 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, and that the radial distances are evaluated with respect to a thread vertex adjacent to said thread root of the helix of the male threaded portion. The helix-bearing side of the male threaded portion may form an angle between 1 and 5°, preferably between 1.25 and 3.75° with respect to a perpendicular to the longitudinal axis, and is parallel to the helix-bearing side of the female threaded portion, with a tolerance of + / - 0.25° in the inclination of these helix-bearing sides with respect to the longitudinal axis. In particular, the helix-bearing side of the male threaded portion may form an angle less than or equal to 90° with an adjacent thread root of this helix. For example, the helix of the female threaded portion may be frustoconical, preferably exclusively frustoconical, for example with a taper between 5% and 15%, preferably 8% and 12%. In this case, the helix of the male threaded portion may also consist of at least a frustoconical part with a taper identical to that of the helix of the female threaded portion. According to a particular embodiment of the invention, the pitch of the carrier side LFLp and the pitch of the attachment side SFLp can be between 5 and 20 mm, preferably between 6 and 8 mm. In a preferred embodiment of the invention, the male threaded portion and the female threaded portion may each consist of a single helix. In this case, the helices of the male threaded portion and the female threaded portion may each consist of at least 3 turns, preferably at least 4 turns. To facilitate assembly, the thread crests and thread roots of the male and female threaded portions may have a taper less than that of the threaded portions themselves; for example, they may be parallel to the longitudinal axis of the joint. In this case, the radial height of one of the mating sides of the male threaded portion may be greater than the radial height of one of the bearing sides of this male threaded portion. Other features and advantages of the invention will become apparent from reading the detailed description that follows, with reference to the accompanying figures, which illustrate: [Fig. 1]: an external profile view of a first tube according to the invention; [Fig. 2]: a longitudinal cross-sectional view of a second tube according to the invention; [Fig. 3]: a partial longitudinal cross-sectional view of a male connector of the first tube in Figure 1; [Fig. 4]: a partial longitudinal cross-sectional view of a female connector of the second tube in figure 2; [Fig. 5]: a partial longitudinal cross-sectional view of a male connector of the first tube of Figure 1 assembled to a female connector of the second tube of Figure 2, this cross-sectional view also indicating the pressure levels achieved inside the joint after assembly; [Fig. 6]: a partial longitudinal cross-sectional view of a female non-threaded intermediate portion of a female connector according to the invention; [Fig. 7]: a partial longitudinal cross-sectional view of a male non-threaded intermediate portion of a male connector according to the invention; [Fig. 8]: a partial longitudinal cross-sectional view of an internal unthreaded female portion of a female connector according to the invention; [Fig. 9]: a partial longitudinal cross-sectional view of an internal unthreaded male portion of a male connector according to the invention; [Fig. 10]: a partial longitudinal cross-sectional view of a male threaded portion of a male connector according to the invention; [Fig. 11]: a partial longitudinal cross-sectional view of a tooth of a male threaded portion according to figure 10; [Fig. 12]: a partial longitudinal cross-sectional view of a female threaded portion of a female connector according to the invention; [Fig. 13]: a partial longitudinal cross-sectional view of a tooth of a female threaded portion according to figure 12; [Fig. 14]: a partial longitudinal cross-sectional view of the male threaded portion of figure 10 in the assembled position with the female threaded portion of figure 12; [Fig. 15]: a partial longitudinal cross-sectional view of a throat for evacuating the grease overpressure formed in a female threaded portion of a female connector according to the invention. As can be seen in Figure 1, a first tube 12 consists of a tube body 120. This first tube 12 has an axial length of several meters, for example, on the order of 10 to 15 m. It extends along a longitudinal axis X. At a first axial end 121 of this first tube 12, the tube 12 has a male connector 18. The tube body 120 has an outside diameter, generally referred to as the nominal outside diameter. Opposite the first axial end 121, the tube has a second axial end 122. This second axial end 122 has a larger outside diameter than the tube body 120. Figure 2 shows a longitudinal cross-sectional view of a second tube 14, identical to the first tube 12. This second tube 14 consists of a tube body 140 provided at a first axial end 141 with a male connector and at a second axial end 142 with a female connector 16. The male connector is machined on the outer surface of the first axial end 121. The second axial end 142 has a larger outer diameter than the tube body 140. The female connector is machined on the inner surface of this second end. In the continuation of the description, we will describe a joint formed between the female connector 16 of the second tube 14 and the connector 18 of the first tube 12. For example, Figure 5 represents a joint according to the invention. This joint is called a semi-flush joint, insofar as the outside diameter at the level of the formed joint is less than 105% or even 103% of the outside diameter of the tube bodies 120, 140. The invention applies to joints that can be flush, namely, those for which the outside diameter at the joint level is less than 101% of the nominal outside diameter ODnom. In the example described, the first and second tubes 12 and 14 are identical, and each consists of a male connector 18 at its respective first end 121 and 141, and each also consists of a female connector 16 at its respective second end 122 and 142. Before manufacturing the male connector 18, the first distal end 121, 141 is tapered. The taper reduces the inside diameter of the first end 121, 141 by creating a contraction 13 that forms a transition between the pipe body and the first end. Preferably, the inside diameter of the first end is restricted relative to the nominal inside diameter of the pipe body, so that after joint assembly, the inside diameter at the joint level is greater than 94% of the nominal inside diameter. The first end 121, 141 extends between a free edge 19 and the pipe body. This first end, which carries a male connector 18, represents a certain axial length, on the order of 20 to 30 cm, between the free edge 19 and the pipe body. Similarly, before manufacturing the female connector 16 at the level of the second distal end 122, 142, the second end undergoes a diametral expansion. As shown in Figures 1 and 2, the diametral expansion 15 is performed 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, on the order of 20 to 30 cm, between the free edge 17 and the tube body. The male connector 18 consists of two threaded portions, 18a and 18b. These two threaded portions extend along the X-axis in successive sections. They are separated from each other by an intermediate unthreaded portion 20. The male threaded portions 18a and 18b are radially offset with respect to the X-axis. The male connector 18 has a male stop flange 22 on the intermediate unthreaded portion 20. The intermediate male stop 22 defines an annular surface in a plane perpendicular to the X-axis. Preferably, each of the male threaded portions 18a and 18b consists of a single turn forming a single helix. Preferably, the pitch of the helices of each of the threaded portions is identical. Between the free edge 19 and the first threaded portion 18a, an internal unthreaded male portion 30 consists of an internal sealing surface 25. Between the intermediate male stop 22 and the second male threaded portion 18b, the intermediate non-threaded male portion 20 consists of an intermediate sealing surface 26. The female connector 16 consists of two threaded portions, 16a and 16b. These two threaded portions extend along the X-axis in successive sections. They are separated from each other by an intermediate unthreaded portion 21. The female threaded portions 16a and 16b are radially offset with respect to the X-axis. The female connector 16 has an intermediate stop flange 24 on the intermediate unthreaded portion 21. The intermediate female stop 24 defines an annular surface in a plane perpendicular to the X-axis. Preferably, each of the male threaded portions 18a and 18b consists of a single turn forming a single helix. 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 connector 16 consists of an internal female non-threaded portion 31 consisting of an internal sealing surface 27. Between the intermediate stop surface 24 and the second female threaded portion 16b, the intermediate non-threaded female portion 21 consists of an intermediate sealing surface 29. In the assembled position of the joint, Figure 5, the free edge 19 remains at a non-zero axial distance d, for example more than 0.1 mm from the female connector 16; The helix of the first male threaded portion 18a engages with that of the first female threaded portion 16a, the helix of the second male threaded portion 18b engages with that of the second female threaded portion 16b; The male intermediate stop 22 comes into butt contact with the female intermediate stop 24, the male internal sealing surface 25 comes into contact which radially interferes with the female internal sealing surface 26 to form an internal metal-to-metal seal that preserves the joint requirements under internal pressure, the male intermediate sealing surface 27 comes into contact which radially interferes with the female intermediate sealing surface 28 to form an intermediate metal-to-metal seal that preserves the joint requirements under external pressure, the free edge 17 of the female connector is at a non-zero axial distance from the male connector. The joint according to the invention consists of a single axial stop, orthogonal to the X axis, obtained by the contact between the intermediate stops 22 and 24, and whose main function is to mark the end of the threading of the joint. The radial thickness of the contact surfaces of these intermediate stops 22 and 24 is less than 20% of the cross-section of the 120 or 140 pipe, which is defined as the area between ODnom and IDnom. The manufacturing of the male and female connectors allows for a manufacturing tolerance that permits the use of any compliant pipe whose ODnom and IDnom dimensions meet the tolerances specified in the API standards. The intermediate stop does absorb some of the compressive forces of the connection, but its dimensions do not allow it to absorb all the compressive requirements. On either side of the internal metal-to-metal seal, the internal male unthreaded portion 30 is at a non-zero radial distance from the internal female unthreaded portion 31. The internal metal-to-metal seal is achieved at a distance from the edges of this internal unthreaded zone 30-31. Apart from the contacts obtained for the intermediate metal-to-metal seal and for the stop of the stop flanges 22 and 24, the intermediate male unthreaded portion 20 is at a non-zero radial distance from the internal female unthreaded portion 21. The intermediate metal-to-metal seal is achieved at a distance from the edges of this intermediate unthreaded zone 2021. As shown in Figure 2, the internal metal-to-metal seal experiences higher pressures than the intermediate seal. The intermediate seal is useful for ensuring a tight seal under external pressure forces. Between the second threaded portion and the intermediate stop, the intermediate seal benefits from the thickness of the male connector (18 mm) and the female connector (16 mm) to the right of this sealing surface, which allows for high contact stability, particularly under heavy tensile stress: there is no separation of the surfaces. In detail, in Figures 6 and 7, according to one embodiment of the invention, the intermediate sealing is of the cone-cone type. The male intermediate sealing surface 27 and the female intermediate sealing surface 28 are frustoconical with identical taper. Alternatively, these surfaces 27 and 28 may have almost identical taper, in that the taper of one may be within ±1% of the taper of the other. For example, the taper of these surfaces 27 and 28 may be between 15% and 25%, for example, 20% ±1%, or even both equal to 20%. The male intermediate sealing surface 27 is joined on one side by a convex-concave radiated portion 32 to a cylindrical surface 33 that is adjacent to the second threaded portion 18b, and is joined on the other side by another convex-concave radiated portion 34 to another cylindrical surface 35 adjacent to the male stop flange 22. The cylindrical surface 35 is joined to the male stop flange 22 by a connecting radius 36. The convex-concave radiated portions 32 and 34 are arranged such that they are convex on the side adjacent to the male intermediate sealing surface 27, and concave when joined respectively to the cylindrical surfaces to which they are respectively adjacent. In practice, the convex-concave radiated parts 32 and 34 are such that the outside 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 stop 22. Similarly, the female intermediate sealing surface 28 is joined on one side by a convex-concave radiated portion 37 to a cylindrical surface 38 adjacent to the second female threaded portion 16b, and on the other side by another convex-concave radiated portion 39 to another cylindrical surface 40 adjacent to the female stop flange 24. The convex-concave radiated portions 37 and 39 are arranged so that they are convex on the side adjacent to the female intermediate sealing surface 28, and concave when joined to the cylindrical surfaces to which they are respectively adjacent. In practice, the convex-concave radiated portions 37 and 39 are such that the inside diameter at the level of the cylindrical surface 38 adjacent to the female threaded portion 14b is larger than that of the cylindrical surface 40 adjacent to the female stop 24. The convex-concave surfaces 32, 34, 37, and 39 are joined tangentially. The convex-concave surfaces 32, 34, 37, and 39 consist of the radiated parts joined tangentially to each other, with a radius of curvature between 3 and 30 mm. IVIA / a / ZUZZ / UUU 104 The cylindrical surface 40 is more precisely joined to the female stop flange 24 by a concave joint 41. The concave joint 41 has a truncated conical portion tangentially joined at a radius of curvature less than 1 mm, such that the radius of curvature of the concave joint 41 is tangent to the female stop flange 42, in order to avoid pressure concentration in the vicinity of the female stop flange 24. To avoid pressure concentration in the vicinity of the male stop flange 22, the male stop flange is connected by a concave joint 42 of wide radius to a cylindrical surface 43 adjacent to one end of the first male threaded portion 18a. Similarly, the female stop flange 24 is joined by a joining radius 44 to an adjacent cylindrical surface 45 of the first female threaded portion 16a. In practice, given the manufacturing process of the respective male and female threaded portions, the cylindrical surface 45 is adjacent to a groove 46 with a cylindrical bottom, tolerated for the removal of the thread-cutting tool from the first female threaded portion 16a. The groove with a cylindrical bottom 46 defines an inside diameter larger than the inside diameter of the cylindrical surface 45. The groove 46 consists of a truncated conical joining surface to the cylindrical surface 45. In detail, in Figures 8 and 9, according to one embodiment of the invention, the internal sealing is of the torus-cone type. In this example, the male internal sealing surface 25 is frustoconical, and the female internal sealing surface 26 is toroidal. In Figure 8, the female internal sealing surface 26 is a curve formed by several adjacent and mutually tangent convex radiated portions. In one example, it consists of two adjacent radiated portions with radii R1 and R2, respectively, such that radiated portion R1 is closer to the tube body 140 than radiated portion R2, and radius R1 is smaller than radius R2. Preferably, radii R1 and R2 are greater than 30 mm. This female toroidal internal sealing surface 26 is joined, on the tube body side 140, to a cylindrical surface 47 by a radius of curvature 48 with a radius at least 3 times smaller than radii R1 and R2.On the opposite side, it is joined to a cylindrical surface 50, adjacent to the first female threaded portion 16a, by a convex-concave surface that is joined tangentially on one side to the cylindrical surface 50, and on the other side to the sealing surface 26. To make contact with the female internal sealing surface 26, the male internal sealing surface 25 consists of a frustoconical portion with a taper of between 10 and 20%. At the level of the inner perimeter of the male connector 12, the inner surface of the male connector is chamfered 51, so that the internal unthreaded portion 30 is of lesser thickness, and even if the internal sealing induces an inner deflection of the edge defined between the internal sealing surface 25 and the free end 19, the male connector 18 does not ML / a / ZUZZ / UUU 104 significantly modifies the inner diameter of the passage, called the drift of the connection. The internal male sealing surface 25 connects tangentially to a convex surface 52, of wide radius of curvature, which is in a relationship 53 to the free edge 19 defined perpendicular to the X-axis. On the opposite side of the free edge 19, the male sealing surface joins tangentially to a cylindrical surface 54 above the threading start of the first male threaded portion 18a. This cylindrical surface 54 allows the thread-making tools to begin. The primary radius R2 is determined to control pressure and the plasticization of the female connector 16 above the internal seal. This radius R2 is then intended to control the seal for requirements where contact pressure is critical. When the contact pressure is more moderate, the deflection of the male connector's edge is also more moderate, and the position of the seal point is then shifted further into the tube body 140, so the value of radius R2 is no longer necessary. A radius R1 smaller than radius R2 is then used for these operating points. The radial thickness of the seal surface along the X-axis is such that less thickness is used to manufacture this internal female seal surface 26.Therefore, the female connector can be manufactured on tubes of any outside diameter, automatically increasing its effectiveness for a given tube thickness. A bend radius of 48 also reduces the amount of material required to manufacture the female connector, further increasing its effectiveness for a given tube thickness. During threading, the initial contact of the male internal sealing surface 25 is made with the portion of radius R2. This initial contact, which can be severe, is mitigated by the high R2 value, which helps limit the risk of seizing. Once contact is established, threading continues by shifting the contact between the male internal sealing surface 25 and the portion of radius R1. This particular configuration of the female internal sealing surface 26 improves performance and increases the number of threading and unthreading cycles that the gasket, according to the invention, can withstand. In the continuation of the description, we will now describe the threading. In the embodiment depicted in Figures 1 to 9, all the male threaded portions 18a, 18b and female portions 16a and 16b respectively each consist of a single helix. However, as a variant, remaining within the scope of the invention, a male threaded portion and its complementary threaded portion may consist of the same number of helices greater than 2 helices. MA / a / ZUZZ / UUU 104 A helix is ​​defined by a helical outgrowth. A helix consists of a carrier side, a thread vertex, a mating side, and a thread root. The thread root, like the thread vertex, is defined between a carrier side and a mating side such that on a helix carried by the male connector 18, the thread root is radially closer to the longitudinal X-axis than the thread vertex; On a helix carried by the female connector 16, the thread bottom of this helix is ​​radially further from the longitudinal axis X than the thread vertex. A longitudinal cross-section profile of this helical outgrowth is called almost trapezoidal, insofar as a thread vertex extends axially between the carrier side and the engagement side respectively. Figure 10 represents a truncated conical portion 74 over two turns of the helix of the first and second male threaded portion 18a, respectively 18b. The structure described below for the helix is ​​reproduced over at least several turns, over at least 3 turns, preserving the dimensions, shapes and proportions stated below. The helix of the male threaded portion consists of a carrier side LFp, a thread vertex 60, a mating side SFp, and a thread root 61. The root 60 and the vertex 61 form segments parallel to the longitudinal axis X. The thread root 61 is joined by a concave radial joint 62 to the mating side SFp. The concave radial joint 62 is such that the thread root 61 and the mating side SFp form an angle greater than 90°. The mating side SFp is straight and forms an angle 63 with respect to a perpendicular N to the longitudinal axis X. The thread root 61 is joined by a second concave radial joint 64 to the carrier side LFp, at an end of the thread root 61 opposite the end where this thread root is joined to the mating side SFp. The second concave radial joint 64 is such that the thread root 61 and the bearing side LFp form an angle less than 90°. The bearing side LFp is rectilinear and forms an angle 65 with respect to the perpendicular N to the longitudinal axis X. Angle 65 is equal to angle 63 with close manufacturing tolerances, namely + / - 0.25°. The SFp engagement sides are chosen parallel to the LFp bearing sides so that the engagement sides take on a portion of the loads observed at the joint under certain compressive pressures. Angle 63, for example, is between 1 and 5°, preferably between 1.25 and 3.75°. In more detail, Figure 11 shows that the radial joint 62 is controlled to ensure the radial dimension of the engagement side SFp. The thread root 61, on the other hand, can consist of a pitch with two stepped cylindrical portions 61a and 61b, such that the cylindrical portion 61a immediately adjacent to the radial joint 62 is radially further from the longitudinal axis X than the cylindrical portion 61b adjacent to the carrier side LFp. Vertex 60 is joined to the engagement side SFp by a convex radial joint 66. This vertex 60 is joined to the carrier side LFp by a complex convex surface 67 consisting of a truncated conical portion 68 adjacent to the cylindrical portion of vertex 60, and this truncated conical portion 68 is joined by a radius of curvature 69 to the carrier side LFp. The radial height of the mating side SFp is greater than the radial height of the carrying side LFp, so that the male threaded portion consists of a truncated conical portion in the sense that an imaginary line PL (pitch Une) passing through the center of the mating sides SFp and the successive carrying sides LFp of the helix defines a taper angle 70 with respect to the longitudinal axis X. In this truncated conical portion, the helix is ​​defined between the surfaces of two imaginary wrapped surfaces 71 and 72, respectively parallel to the pitch Une PL. The lower imaginary wrapped surface 71 passes through the points of tangency between the root of the thread 61 and the radial joint 62 adjacent to the mating side SFp, of each turn of the helix in this truncated conical portion. The imaginary upper wrapped surface 72 passes through a point of tangency between the convex radiated joint 66 adjacent to the engagement side SFp and the thread vertex 60. The 70° angle is such that the taper of this male threaded portion 18a and / or 18b is between 5 and 15%, preferably between 8 and 12%. The helix comprises, in addition to the truncated conical portion 74 described above, a cylindrical portion 73 at one end of the helix, this cylindrical portion 73 being developed over more than one turn, and preferably less than three turns, in particular less than two turns. In the described embodiment, this cylindrical end 73 of the helix is ​​located on the end side of the male threaded portion closest axially to the free edge 19. In particular, the first male threaded portion 18a and the second male threaded portion 18b each consist of such a cylindrical portion 73 adjacent to the truncated conical portion 74 of the helix. The cylindrical portion 73 of the helix is ​​such that successive bottoms 61 of this cylindrical portion are parallel and collinear with each other. The imaginary lower wrapped surface 71 becomes parallel to the X-axis in this cylindrical portion, while the imaginary upper wrapped surface 72 maintains the same taper for the truncated conical part 74 and the cylindrical part 73. The helix of the male threaded portion further comprises an imperfect portion 75 at an opposite end of the male threaded portion, namely, at the end of the helix farthest 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 truncated conical portion 74, such that the truncated conical portion 74 is framed between the imperfect portion and the cylindrical portion 73. This imperfect portion 75 is such that the threads are of lower heights, and successive vertices 60 of this imperfect portion 75 are parallel and collinear with each other. The imaginary upper wrapped surface 72 becomes parallel to the X-axis in this imperfect portion 75. This imperfect portion 75 extends over more than one turn, and preferably less than three turns, particularly less than two turns.In the imperfect portion 75, the lower imaginary wrapped surface 71 has the same conical shape as that observed in the truncated conical portion 74. The presence of the cylindrical portion 73 allows the radial volume of the male threaded portion to be limited to the wall thickness in which the male connector is formed. Therefore, a greater minimum thickness can be guaranteed at the level of the internal 25 and intermediate 27 male sealing surfaces. This configuration of the male threaded portion improves the sealing performance. Furthermore, the presence of the cylindrical portion 73 adjacent to the truncated conical portion 74 prevents any abrupt variation in the rigidity of the internal male non-threaded portion 30. This configuration prevents premature plasticization of the areas of the joint that receive maximum pressure. The helix of the male threaded portion is such that a pitch of the engagement side SFLp is constant in the truncated conical portion 74, and also constant in the imperfect portion 75. The pitch is in particular the same in the truncated conical portion 74 and imperfect portion 75. A pitch of the engagement side LFLp is the same in the truncated conical portion 74 and imperfect portion 75, such that this pitch LFLp is also equal to the pitch of the engagement side SFLp. The pitch of the engagement side SFLpl and the pitch of the carrier side LFLpl are equal to a constant kl for the first male threaded portion 18a. Similarly, for the second male threaded portion 18b, the pitch of the engagement side SFLp2 and the pitch of the carrier side LFLp2 are equal to this same constant kl. According to the invention, this constant kl is, for example, 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 engagement side SFp and the carrier side LFp, to the points of intersection with the pitch Une PL, is such that this tooth has a width less than half of the constant kl, in particular less than 40% of the kl value. Figure 12 represents a truncated conical portion 94 over two turns of the helix of the first and second female threaded portion 16a, respectively 16b. The structure described below for the helix is ​​reproduced over at least several turns, over at least 3 turns, preserving the dimensions, shapes and proportions stated below. The helix of the female threaded portion consists of a carrier side LFb, a thread vertex 80, a mating side SFb, and a thread root 81. The root 80 and the vertex 81 form segments parallel to the longitudinal axis X. The thread root 81 is joined by a concave radial joint 82 to the mating side SFb. The concave radial joint 82 is such that the thread root 81 and the mating side SFb form an angle greater than 90°. In the same way as is done at the level of the male thread root 61, the thread root 81 can consist of a pitch with two stepped cylindrical portions 81a and 81b, such that the cylindrical portion 81a immediately adjacent to the concave radial joint 82 is radially closer to the longitudinal axis X than the cylindrical portion 81b of this root 81 that is adjacent to the carrier side LFp. The engagement side SFp is straight and forms an angle 83 with respect to a perpendicular N to the longitudinal axis X. The root thread 81 is joined by a second concave radial joint 84 to the carrier side LFb, at an end of the root thread 81 opposite to the end where this root thread is joined to the engagement side SFb. The second concave radial joint 84 is such that the root thread 81 and the carrier side LFb form an angle of less than 90°. The carrier side LFb is straight and forms an angle 85 with respect to the perpendicular N to the longitudinal axis X. to know, to know, The angle + / - 0.25°. The angle + / - 0.25°. The angle is equal to the angle with close manufacturing tolerances, namely, + / - 0.25°. Angle 83 is, for example, between 1 and 5°, preferably between 1.25 and 3.75°. In more detail, as shown in Figure 13, vertex 80 is joined to the engagement side SFb by a convex radial joint 86. The radial joint 86 comprises a tangential joining radius 86a with the engagement side SFb, a tangential joining radius 86c with vertex 80, and a truncated conical surface 86b tangentially joined to the tangential joints 86a and 86c, respectively. The truncated conical surface 86b forms an obtuse angle 86d, for example, an open angle between 190° and 240°, preferably on the order of 225°, with respect to the engagement side SFb. The truncated conical surface 86b forms a bevel that facilitates the insertion of the male connector into the female connector. This truncated conical surface 86b reduces the axial width of the vertex 80 so that an additional volume is defined between this truncated conical surface 86b and the complementary profile of the male threaded portion, which this volume also allows to contribute to the reduction of grease pressure in the threading. This vertex 80 is joined to the carrier side LFb by a complex convex surface 87 consisting of a truncated conical portion 88 adjacent to the cylindrical portion of vertex 80, and this truncated conical portion 88 is joined by a radius of curvature 89 to the carrier side LFb. The radial height of the carrier side LFb is greater than the radial height of the attachment side SFb, so that the female threaded portion consists of a truncated conical portion in the sense that an imaginary line PL (pitch Une) passing through the center of the attachment sides SFb and the successive carrier sides LFb of the helix defines a taper angle of 90 with respect to the longitudinal axis X. The taper of this imaginary line is the same as that defined for the truncated conical portion 75 of the male threaded portion, which these PL lines overlap in the assembled position of the joint as visible in Figure 14. In this truncated conical portion 94 of the female threaded portion, the helix is ​​defined between the surfaces of two imaginary wrapped surfaces 91 and 92, respectively truncated conical and parallel to the pitch Une PL. The upper imaginary wrapped surface 91 passes through the points of tangency between the thread root 81 and the radiated joint 82 adjacent to the engagement side SFb, of each turn of the helix in this truncated conical portion 94. The upper imaginary wrapped surface 92 passes through a point of tangency between the convex radiated joint 86 adjacent to the engagement side SFb and the thread vertex 80. The 90° angle is such that the taper of this female threaded portion 16a and / or 16b is between 5 and 15%, preferably between 8 and 12%. The helix comprises, in addition to the truncated conical portion 94 described above, an imperfect portion at one end of the helix, this imperfect portion 95 extending over more than one turn, and preferably less than three turns, particularly less than two turns. In the described embodiment, this end of the helix is ​​located on the side of the female threaded portion furthest axially from the free edge 17 of the female connector. In particular, each of the first female threaded portion 16a and the second female threaded portion 16b comprises such an imperfect portion 95 adjacent to the truncated conical portion 94 of the helix. The imperfect portion 95 is such that the threads are of smaller heights, and the successive vertices 80 of this imperfect portion 95 are parallel and collinear with each other. The lower imaginary wrapped surface 92 becomes parallel to the X-axis in this imperfect portion 95. In the imperfect portion 95, the upper imaginary wrapped surface 91 has the same taper as that observed in the frustum cone portion 94. In the assembled position of the male connector with the female connector, the imperfect portion 95 of a female threaded portion engages with the cylindrical portion 73 of the corresponding male threaded portion. In the embodiment according to the invention, the truncated conical portion 94 of the female threaded portion has more turns than the truncated conical portion 74 of the male threaded portion. Indeed, the imperfect portion 75 of the male threaded portion engages with the truncated conical portion of the female threaded portion in the assembled position of the joint. In particular, the first male threaded portion 18a may consist of more turns than the second male threaded portion 18b. In particular, the first female threaded portion 16a may consist of more turns than the second female threaded portion 16b. In particular, the truncated conical portion 74 of the first male threaded portion 18a may consist of more turns than the truncated conical portion 74 of the second male threaded portion 18b. In particular, the truncated conical portion 94 of the first female threaded portion 16a may consist of more turns than the truncated conical portion 94 of the second female threaded portion 16b. The helix of the female threaded portion is such that a pitch of the engagement side SFLb is constant in the truncated conical portion 94, and equally constant in the imperfect portion 95. The pitch is in particular the same in the truncated conical portion 94 and imperfect portion 95. A pitch of the engagement side LFLb is the same in the truncated conical portion 94 and imperfect portion 95, such that this pitch LFLb is also equal to the pitch of the engagement side SFLb. The pitch of the engagement side SFLbl and the pitch of the carrier side LFLbl 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 engagement side SFLb2 and the pitch of the carrier side LFLb2 are equal to this same constant k2. According to the invention, the constants kl and k2 are equal to each other, and may also be designated by the term constant k. Given manufacturing tolerances, in the spirit 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 engagement side SFb and the carrier side LFb, to the points of intersection with the pitch Une PL, is such that this tooth has a width greater than the tooth width Wtp of the truncated conical portion 74 of the male threaded portion. In practice, according to the invention and the example shown, it is important to define the teeth of the male threaded portions as being narrower than the teeth of the female threaded portions. For example, in the embodiment shown, [Math 9] 50% < ^ < 80% W tb AND [Math 10] Wtp + Wtb < k Ideally, [Math 11] Wtp 55% < 777^7 < 75% Wtb Even [Math 12] Wtp 67% < 73% Wtb The female threaded portions are wider than the teeth of the male threaded portion, so the female teeth have less tendency to plasticize. Now, in a joint according to the invention, the pressures are most clearly observed in a zone 99 that extends between the first engaged teeth on the side of the internal sealing surfaces 25 and 26, and said sealing surfaces, see figure 5. The maximum shear lines that can be modeled in a joint according to the invention under compression requirements are represented at 45° with respect to vertex 60, on the side where this vertex joins the engagement side SFp. Conversely, the maximum shear lines that can be modeled in a joint according to the invention under tension requirements are represented at 45° with respect to vertex 60, on the side where this vertex joins the load-bearing side LFp. The intersection between these modeled shear lines allows the definition of a pressure maximum triangle above each vertex of the male threaded portion. These triangles locate the areas where the risk of plastic deformation inside the female connector is highest.The inventors have discovered that to preserve the effectiveness of the connection, it is essential to limit the height of these triangles, then choose a ratio such that it is claimed to limit plasticization in the female connector that has a restricted thickness as a consequence of the design in the integral joint. In the assembled position, as shown in Figure 14, the bearing sides LFp and LFb are in contact, and an axial clearance 100 is maintained between the mating sides SFp and SFb. Similarly, a radial clearance 101 is maintained between the vertices 60 of the male threaded portion and the roots 81 of the female threaded portion, while imaginary lines 71 and 91 overlap to the extent that the vertex 80 of the female threaded portion comes into contact with the thread root 61 of the male threaded portion. The radial set 101 also allows limiting the sizing of the maximum pressure zones in the female connector. For example, clearances 100 and 101 are between 0.1 mm and 0.5 mm, preferably between 0.2 and 0.3 mm. With such axial clearance, the tooth widths meet the following condition: ML / a / ZUZZ / UUU 104 [Math 13] Wtp + Wtb < k - 0.1 mm The male threaded portion, which is cylindrical-conical, has little free volume between the helices of the assembled male and female threaded portions. When the joint according to the invention is used with threading grease applied to the male and female connectors before assembly, there is little free space available to prevent grease pressure buildup within the connection. According to the invention, an annular groove 110 is provided in the female threaded portion, and in particular in the first female threaded portion 16a, to collect excess grease that flows back. The purpose of this groove is to allow grease to accumulate locally during threading or during use of the connection under certain temperature and pressure conditions. This annular groove is provided in the female threaded portion located between two sealing surfaces. In the embodiment shown, lacking a seal between the free edge 17 of the female connector and the second female threaded portion, no annular throat is provided in the second female threaded portion. In Figure 15, the annular throat 110 is defined between the imaginary inner line 92 and outer line 91. For example, the annular throat 110 has an axial width G on the order of the constant k. The throat 110 consists of a truncated conical bottom 111, with a taper identical to that of the female threaded portion. The annular throat is asymmetrical. On one side of the bottom 111, on the side of the internal sealing surface 26, the bottom 111 is joined to a straight section 112 that forms an angle 113 with the perpendicular N between 10 and 30°. On the opposite side of the bottom 111, on the side of the intermediate sealing surface 28, the bottom 111 is joined to another straight section 114 that forms an angle 115 with the perpendicular N between 30 and 85°. This throat allows the grease to degas without creating a temporary loss of airtightness, nor running the risk of locally plasticizing the connection, when the joint is placed at a very great depth and subjected to temperatures of around 180° C. The invention also applies to threaded joints between a male connector consisting of a single threaded portion and a female connector also consisting of a single threaded portion. These joints, according to the invention (not shown), may consist of one or two metal-to-metal seals and an axial stop. The invention also applies to assembled threaded joints.

Claims

1. A tubular threaded joint for drilling or exploiting hydrocarbon wells, comprising a first tube provided at a first distal end with a male connector and a second tube provided at a second distal end with a female connector, wherein the male connector is suitable for assembly by threading with the female connector, the first tube assembled to the second tube together defining a longitudinal axis, wherein the male connector consists of a male threaded portion, wherein the female connector consists of a female threaded portion engaged with the male threaded portion when the joint is assembled, characterized in that the male and female threaded portions each consist of at least one helix provided with a bearing side, a thread vertex, an engagement side, and a thread root, such as a bearing side pitch LFLp and an engagement side pitch SFLp of the male threaded portion,and respectively a carrier-side pitch LFLb and a engagement-side pitch SFLb of the female threaded portion satisfy the following condition, for at least two consecutive turns of the respective helices of the male and female threaded portions: [Math 14] SFLp = LFLp = SFLb = LFLb = ky such that along the longitudinal axis, in these at least two consecutive turns, a helix width (Wtp) of the male threaded portion and a helix width of the corresponding female threaded portion (Wtb) are such that [Math 15] 50% < ^ < 80% OR [Math 16] 50% < ^ < 80% AND [Math 17] Wtp + Wtb < k, 2. Tubular threaded joint according to claim 1 characterized in that the following mathematical condition is satisfied [Math 18] 55% < ^ < 75% 3. Tubular threaded joint according to claim 1 or 2 characterized in that the following mathematical condition is satisfied [Math 19] 67% < ^ < 73% 4. Tubular threaded joint according to any one of the preceding claims characterized in that the tooth width (Wtp) of the helix of the male threaded portion is between 2.5 and 3.5 mm.

5. Tubular threaded joint according to any one of the preceding claims characterized in that the tooth width (Wtb) of the helix of the female threaded portion is between 3.7 and 4.5 mm.

6. Tubular threaded joint according to any one of the preceding claims characterized in that the tooth widths (Wtp, Wtb) of the helices of the male and female threaded portions respectively meet the following condition: [Math 20] Wtp + Wtb < k — 0.1 mm over the aforementioned at least two consecutive turns of these helices.

7. Tubular threaded joint according to any one of the preceding claims characterized in that the tooth widths of the complete helices of the male and respective female threaded portions satisfy the following condition: for each turn (n), a tooth width of the male thread (Wtp n) and a tooth width of the female thread (Wtb n) are such that for all n: [Math 21] Wtpn + Wtbn < k — 0.1 mm 8. Tubular threaded joint according to any one of the preceding claims characterized in that a portion of the engagement side is parallel to a portion of the carrier side, with a tolerance of + / - 0.25° in the inclination of these portions with respect to the longitudinal axis.

9. Tubular threaded joint according to any one of the preceding claims characterized in that the engagement side and the helix-carrying side of the male threaded portion are respectively straight, and respectively joined by the connection radii (62, 64, 66, 68) to the adjacent thread vertex (60) and thread root (61).

10. Tubular threaded joint according to any one of the preceding claims characterized in that the engagement side (SFb) of the helix of the female threaded portion consists of a straight segment connected to the thread vertex (80) by a segment inclined with respect to the engagement side so as to propose a convexity, such that these two segments form between each other an obtuse angle (86d) between 190° and 260°, for example on the order of 225°.

11. Tubular threaded joint according to any one of the preceding claims characterized in that the thread root of the helix of the male threaded portion comprises two segments (61a, 61b), a first male thread root segment (61a) located on the side of the engagement side and a second male thread root segment (61b) located on the side of the carrier side, 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, and that the radial distances are evaluated with respect to a thread vertex adjacent to said thread root of the helix of the male threaded portion.

12. Tubular threaded joint according to any one of the preceding claims characterized in that the helix-bearing side of the male threaded portion forms an angle between 1° and 5°, preferably between 1.25° and 3.75° with respect to a perpendicular to the longitudinal axis, and is parallel to the helix-bearing side of the female threaded portion, with a tolerance of + / - 0.25° in the inclination of these bearing sides with respect to the longitudinal axis.

13. Tubular threaded joint according to any one of the preceding claims characterized in that the helix-bearing side of the male threaded portion forms an angle less than or equal to 90° with an adjacent thread root of this helix.

14. Tubular threaded joint according to any one of the preceding claims characterized in that the helix of the female threaded portion is truncated conical, preferably exclusively truncated conical, for example with a taper between 5% and 15%, preferably 8% and 12%.

15. Tubular threaded joint according to the preceding claim characterized in that the helix of the male threaded portion consists of at least one truncated conical part with a taper identical to that of the helix of the female threaded portion.

16. Tubular threaded joint according to any one of the preceding claims characterized in that the pitch of the carrier side LFLp and the pitch of the attachment side SFLp are between 5 and 20 mm, preferably between 6 and 8 mm.

17. Tubular threaded joint according to the preceding claim characterized in that the male threaded portion and the female threaded portion each consist of a single helix.

18. Tubular threaded joint according to the preceding claim characterized in that the helices of the male threaded portion and respectively of the female threaded portion consist of at least 3 turns, preferably at least 4 turns.

19. Tubular threaded joint according to the preceding claim characterized in that the thread vertices and thread roots of the male and female threaded portions have a taper less than the taper of said threaded portions, for example that these thread vertices and thread roots are parallel to the longitudinal axis.

20. Tubular threaded joint according to the preceding claim characterized in that a radial height of an engagement side of the male threaded portion is greater than a radial height of a carrier side of this male threaded portion.

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