EA046028B1 - DETERMINING DIMENSIONS OF THREADED AXIAL SPACE - Google Patents

Description

Technical field

The present invention relates to steel components or pipes in the oil and gas production, energy or storage fields for purposes such as well production or hydrocarbon transportation, hydrogen transportation or storage, geothermal energy or carbon capture.

State of the art

As used herein, the term component means any element, fixture or pipe used for drilling or operating a well and containing at least one joint or connector or threaded end and designed to be assembled by screwing onto another component to form a threaded connection with said other component. . The component may be, for example, a pipe or tubular element of relatively long length (in particular approximately ten meters in length), such as a pipe, or even a tubular coupling several tens of centimeters long, or a device for these tubular elements (a hanging device or pendant, section replacement part or adapter, safety valve, drill rod connector or drill joint, sub, etc.).

Components or pipes have threaded ends. These threaded ends are complementary, allowing two tubular elements to be connected to each other: male (nipple) and female (coupling). Thus, there is a male end and a female end. Threaded ends, called premium or semi-premium threaded ends, typically contain at least one thrust surface. The first stop may be formed by two surfaces of the two threaded ends oriented substantially radially and configured to contact each other after the threaded ends are screwed to each other or when subjected to compressive stresses. Stops usually have negative angles relative to the main axis of the joints. Intermediate stops on joints are also known that include at least two threading steps. The threaded end, thrust surface, and sealing surface may form an assembly called a lip. There may be an edge with a thread oriented towards the outside of the pipe, that is, a male edge, and an edge with a thread oriented towards the inside of the pipe, that is, a female edge.

Mechanical processing of a pipe to cut its thread requires the presence of a thread pitch. The concept of thread pitch should be considered in light of the ISO 5408:2009 standard, which provides a definition of thread. The thread pitch must be adjusted to avoid problems during assembly and use of the connection between the male thread and the corresponding female thread.

It is possible that an unexpected deviation between the male pitch or female pitch on the one hand and the calculated pitch on the other hand occurs due to an error in the method or the tapping tools used during machining. This deviation is called pitch error. There are devices that allow you to measure the thread pitch and measure the pitch error, or detect an unacceptable pitch error and proceed to reject the threaded component in question. An example of a measuring device is described in the standard API SPECIFICATION 5B MEASUREMENT AND INSPECTION OF CASING, TUBING AND PIPING THREADS.

However, it is possible that the measurement will be inaccurate due to the measuring instrument itself, which may allow for an imperfection factor. In general, there are safety standards and error limits that must be taken into account for this type of instrument.

Problems may arise after screwing together two tubular elements: male and female. Indeed, it is difficult to measure steps in the connected state and thus possibly detect step errors. The pitch error can be detected by analyzing the make-up curves (see Fig. 10), but at this stage it is too late to do this and both pipes in question will have to be rejected. Rejection criteria are given in the supplier's specifications, for example in the VAM Documentation Book. Thus, during machining, despite precautions and safety measures, some small pitch errors occur at times, which can be individually tolerated and included in the permissible error limit. In this way, the pipe can be inspected while it contains the accumulation of small permissible pitch errors, and continue its production cycle. The Applicant has unexpectedly discovered and established that the accumulation of pitch errors, which may be individually acceptable, can contribute to thread flank displacement throughout the thread. When this accumulation and/or this displacement exceeds a certain threshold value and when they are located against the male and female tubular element, they create a pitch mismatch, the latter leading to an axial interference or mating problem between the thread flanks. A specified axial interference or mating problem may cause too much stress at one or more thread locations due to the compression of the two male and female thread teeth. This excessive tension can cause the threads to join together at too many screw revolutions, to the detriment of screwing, for which the correct alignment of the male part relative to the female part can no longer be ensured. This may mean

- 1 046028 there is both a risk of brittleness or plasticization of the joint and a risk of loss of seal, which could lead to leakage from the joint. A leak can have significant economic and even environmental consequences, such as when a hydrocarbon well leaks while it is in production.

The consequences due to pitch mismatch and therefore leakage problems are further exacerbated when a hard coating with anti-corrosion or lubrication properties is applied.

The present invention solves all the previously mentioned problems. In particular, the present invention provides a configuration capable of eliminating the effects of pitch errors and, in particular, their accumulation on the threads, while ensuring the absence of axial interference or joining problems, as well as sealing.

In accordance with one embodiment, the present invention provides a tubular threaded connection for drilling, hydrocarbon well production, oil and gas transportation, carbon capture, or geothermal energy, comprising a male tubular member and a female tubular member, each of said male or female tubular members comprising respectively, a male threaded portion and a female threaded portion, wherein one or the other of the male or female threaded portions optionally comprises an anti-corrosion and/or lubricating hard coating, wherein said male threaded portion and female threaded portion respectively comprise at least one tooth external thread or one tooth of an internal thread and a threaded axial gap TAG, providing in the mounted state the space between the embedded side of the specified tooth of the external thread and the supporting side of the specified tooth of the internal thread, characterized by the fact that the specified threaded axial gap TAG is greater than the minimum gap TAGmin or equal to it in a way that:

Calculation 1.

ITAGmin = IT(min) * (1/2 ^(LFpbmibl) + 1/2 ( ^FFboxmin ^ + (4 * Epcoat) (Dpmmxri) (Dboxmm) where: ⁰ Epcoat < Epcoat max where: TAGmin - minimum value of the threaded axial gap in mm;

ITmin - minimum pitch mismatch tolerance value in mm;

LFpinmin - minimum value of the axial length of the external thread in mm;

LFboxmin - minimum value of the axial length of the internal thread in mm;

Dpinmin - minimum value of the outer pitch tolerance distance in mm;

Dboxmin - minimum value of the internal pitch tolerance distance in mm;

Epcoat - the value of the thickness of the anti-corrosion and/or lubricating coating in mm.

Thanks to this feature, the connection according to the invention has a thread axial gap (TAG) that corresponds to a minimum threshold value from which the effect of any thread misalignment resulting from the accumulation of pitch error is compensated. This accumulation can also occur due to several individually permissible pitch errors.

Surprisingly, it has been found that when the equation is satisfied, the pitch mismatch risks that may exist in different connections are absorbed by a sufficiently large threaded axial gap. In this way, any risk of axial interference and therefore embrittlement and plasticization due to misalignment caused by quite significant pitch mismatch is completely eliminated.

The term threaded axial gap (TAG) means the distance separating the embedded side of a male thread tooth and the embedded side of a female thread tooth facing the embedded side of a male thread tooth, which can be expressed in mm. This threaded axial spacing is measured at half the height of the male tooth.

The term pitch error refers to the offset resulting from a comparison of the actual pitch, that is, the pitch measured on the manufactured part, and the in-plane pitch, that is, the pitch originally determined on the product drawing.

The term individually permissible pitch error means any thread pitch error that is small enough to be verified and verified during inspection of the thread after machining, the control values being defined by the drawing and/or standard.

The term pitch mismatch refers to the difference between the accumulated pitch error of the male thread and the accumulated pitch error of the internal thread.

In parallel, this equation also allows for control of the screwing level.

According to one embodiment, the pitch mismatch tolerance value is from 0.040 to 0.080 mm, preferably from 0.048 to 0.072 mm.

With this feature, the pitch error can be measured using a traditional monitoring device such as those described in API 5B1. Indeed, for values below the tolerance it is necessary to use more expensive devices, the measurement result of which is not necessarily guaranteed. It is not advisable to have a tolerance value greater than 0.080 mm.

- 2 046028

According to one embodiment, the tubular threaded connection is characterized in that the threaded axial spacing TAG is less than or equal to the maximum spacing TAGmax such that:

Calculation 2.

TAGmax = a* P inLipSurf ace + b + (4 * Epcoat) where; ^{0 E} P ^{coat E} P ^{coat max} a=0.00053;

b=0.14;

where: PinLipSurface - the value of the cross-sectional area of the male edge between the sealing surface and the thrust surface in mm ² ;

a is the value of the correlation slope;

b - value of the intersection point;

Epcoat - the value of the thickness of the anti-corrosion and/or lubricating coating in mm.

This feature eliminates the risk of loss of sealing performance due to the TAG threaded axial gap being too large.

The term sealing performance means the resistance of a joint to combined stresses, both external/internal pressure and tension/compression. The seal may be a liquid or gas seal.

Thanks to this feature, the connection according to the invention is more durable under stresses requiring compression.

Indeed, too large a threaded axial gap can lead to overstressing of the edge and hence plasticization when the connection is subjected to compressive stress. This overvoltage may cause leakage.

Thus, not only is the joint sealed when the equation is satisfied, but the applicant has observed an improvement in sealing performance when using several types of joints in accordance with the invention.

According to one embodiment, the threaded axial gap TAG is between two values TAGmin and TAGmax such that: TAGmin<TAGmax.

According to one embodiment, the tubular threaded connection (1) is characterized in that at least one of the externally threaded parts (4) or the internally threaded parts (5) contains an anti-corrosion and/or lubricating coating, and in that the thickness value anti-corrosion and/or lubricating coating (10) Epcoat is greater than zero.

Due to this feature, adding a hard anti-corrosion and/or lubricating coating to the threads increases the risk of unwanted axial interference. Indeed, the thickness of the hard coating can increase the contact pressure on the thread flanks, increasing the risk of embrittlement or plasticization. Thus, the present invention provides screwing without the additional risk of embrittlement or plasticization of the connection due to the thread coating.

According to one embodiment, the tubular threaded connection is characterized in that the maximum Epcoat max thickness is 0.0075 mm.

Thanks to this feature, a wide variety of anti-corrosion and/or lubricating hard coatings can be included in the configuration, thereby eliminating the risk associated with pitch non-compliance with the maximum value of 0.0075 mm.

According to one embodiment, the anti-corrosion and/or lubricant coating comprises a layer containing zinc and nickel.

Brief description of graphic materials

The present invention may be better understood and other objects, details, features and advantages thereof will become clearer by reference to the following description of several specific embodiments of the invention, given for illustrative and non-limiting purposes only, with reference to the accompanying drawings.

In fig. 1 is a schematic view in longitudinal section of a tubular threaded connection in accordance with the invention, with the supporting sides in contact.

In fig. 2 is a schematic view in longitudinal section of a tubular threaded connection in accordance with the invention, with contact between the embedded sides.

In fig. 3 is a schematic view in longitudinal section of the teeth of the internal and external threads of a tubular threaded connection in accordance with the invention.

In fig. 4 is a schematic longitudinal sectional view of a male end in accordance with the invention.

In fig. 5 is a schematic longitudinal sectional view of a female end in accordance with the invention.

In fig. 6 is a schematic longitudinal sectional view of a finite element analysis of a tubular threaded joint in accordance with the prior art.

- 3 046028

In fig. 7 is a schematic longitudinal sectional view of a finite element analysis of a tubular threaded joint in accordance with the invention.

In fig. 8 is a schematic longitudinal sectional view of an edge of a tubular member with an external thread.

In fig. 9 is a schematic longitudinal sectional view of the arrangement of an external thread and an internal thread in accordance with the invention after screwing.

In fig. 10 shows a pipe screwing curve according to the prior art, including the accumulation of unabsorbed pitch error.

In fig. 11 shows a screwing curve in accordance with the invention, including the accumulation of unabsorbed pitch error.

In fig. 12 is a schematic longitudinal sectional view of a tubular threaded connection including pitch error accumulation.

Description of Embodiments

In the remainder of the description, the terms longitudinal, transverse, vertical, anterior, posterior, left and right are defined in accordance with the usual orthogonal coordinate system as presented in the graphical materials, which contains:

horizontal longitudinal axis X and sectional views from left to right.

In this case, in the description and claims, the terms external or internal, and axial and radial orientation will be used to designate, in accordance with the definitions given in the description, elements of a tubular threaded connection. The longitudinal X axis defines the axial orientation. Radial orientation is directed perpendicular to the longitudinal X axis.

In fig. 1 shows a tubular threaded connection (1) in accordance with the invention, containing a male tubular element (2), containing a part (4) with an external thread, a male sealing surface (28), as well as a male stop (24) and a female tubular element (3 ), containing a part (5) with an internal thread covering the sealing surface (29), as well as a female stop (25). These parts with external (4) and internal (5) threads contain, respectively, several teeth of external (6) and internal (7) threads belonging to the same helical thread line. The definition of a helix thread is given in ISO 5408. The tooth (6) of an external thread contains an outer insert side (14) and an outer support side (12). The tooth (7) of the internal thread contains an internal insert side (15) and an internal support side (13).

The connection shown in FIG. 1 is shown when it is in use under a tensile force, such as the weight of a column in tension vertically, in the direction of the arrow. In this case of normal use, the outer (12) and inner (13) supporting sides are in contact. The outer (14) and inner (15) embedded sides are not necessarily in contact and define the space consisting of the threads of the TAG threaded axial space. However, the stops and sealing surfaces may be in contact.

Another way to determine the thread axial gap TAG is the difference between the width of the groove (LCB) between two teeth of the internal thread and the width of the tooth of the external thread (LP), as shown in FIG. 3.

In fig. 2 shows a tubular threaded connection (1) in accordance with the invention when used under degraded conditions, for example when there is a temperature difference that leads to compressive forces in the threaded connection. The connection will tend to deform under the specified compressive forces. In this case, it is the outer embedded sides (14) that contact the outer embedded sides (15). The stress on the male (28) and female (29) sealing surfaces and the male (24) and female (25) stops that were already in contact increases. The tension on the male (28) and female (29) sealing surfaces, as well as the male (24) and female (25) stops, increases.

In fig. 2 shows that the compression on the embedded sides cannot be increased or intensified indefinitely, and that if a certain limit is exceeded, undesirable axial interference can occur, leading to plasticization of the thread or even damage to it. Thus, this deterioration is caused by too small a threaded axial gap in the assembled state without stress between the outer (14) and outer (15) embedded sides.

In fig. 3 shows a detail of a tubular threaded connection (1) in accordance with the invention and, in particular, the teeth of the external (6) and external (7) threads in the assembled state. The tooth (6) of the external thread contains an outer support side (12) and an outer embedded side (14). The tooth (7) of the internal thread contains an internal support side (13) and an internal embedded side (15). Both the outer (14) and inner (15) embedded sides define a space, the axial dimension of which is the threaded axial space TAG. The specified threaded axial spacing TAG is greater than or equal to the minimum spacing TAGmin such that:

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Calculation 3.

(LFpinmin) (LFboxmin)

TAGmin = IT (min) + (1/2^-^-----+ 1/2^—-----^-) + (4 * Epcoat) (Dpinmin) (D boxmin) < Epcoat < Epcoat max where: g where: TAGmin - minimum value of the threaded axial gap in mm;

ITmin - minimum pitch mismatch tolerance value in mm;

LFpinmin - minimum value of the axial length of the external thread in mm;

LFboxmin - minimum value of the axial length of the internal thread in mm;

Dpinmin - minimum value of the outer pitch tolerance distance in mm;

Dboxmin - minimum value of the internal pitch tolerance distance in mm;

Epcoat - the value of the thickness of the anti-corrosion and/or lubricating coating in mm.

Another way to determine the TAG thread clearance is the difference between the cavity width (LCB) between two internal thread teeth and the male thread tooth width (LP) taken at the midpoint of the male thread height (6).

TAGmin corresponds to the minimum threshold value from which the effect of any thread misalignment caused by the accumulation of pitch errors is canceled; this accumulation can also come from several individually permissible pitch errors. The accumulation of pitch errors and the resulting degradation is illustrated in FIG. 12.

The minimum gap TAGmin is determined depending on the minimum value of the pitch mismatch tolerance ITmin, the minimum value of the axial length of the external thread LFpinmin, the minimum value of the axial length of the internal thread LFboxmin, the minimum value of the external pitch tolerance distance Dpinmin and, finally, the minimum value of the external pitch tolerance distance Dboxmin.

The threaded connection may contain a thread coating and therefore the additional thickness of the Epcoat coating must be taken into account. In the case of FIG. 3 there is no coating and therefore the Epcoat value is 0.

The term axial male thread male LFpinmin or female LFboxmin means the total length of the thread along the axis of the thread of the pipe. Said total thread length is measured from the thread root of the first tooth to the thread root of the last tooth, as illustrated in FIG. 4 and 5.

The term tolerance distance of external pitch Dpinmin or internal pitch Dboxmin means the length at which the pitch is controlled, that is, the total length of the full-profile thread. A full-profile thread can be defined in contrast to a partial-profile thread, that is, a thread whose height is not full. It is also called a vanishing thread, which refers to a partial thread.

The term pitch error tolerance means deviations of the permissible pitch error relative to the nominal plane.

The term pitch mismatch tolerance means the difference between the outer pitch error tolerance and the inner pitch error tolerance.

The term pitch means the distance between two successive supporting sides as defined in ISO 5408.

The pitch mismatch tolerance value ITmin can be from 0.040 to 0.080 mm, preferably from 0.048 to 0.072 mm. Thus, the pitch error can be measured using a traditional monitoring device, such as those described in API 5B1. Indeed, below the minimum value it is necessary to use more expensive devices, the measurement result of which is not necessarily guaranteed. If the value is higher than the maximum, the minimum value of the thread axial gap TAG min is too significant.

It should be noted that the TAGmin value indirectly depends on the axial length of the thread.

To simplify the approach, empirical values of IT min and TAGmin were determined, which are given in the following table. 1 for pipe connections according to nominal pipe outer diameter (OD):

Table 1

OD (in mm) Pipe thickness (in mm) TAGmin (in mm) IT (mm) 114.30 12.7 0.126 0.052 139.70 12.09 0.114 0.041 244.48 13.84 0.165 0.068 355.60 20.62 0.231 0.065

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In fig. 4 shows a male end (20) in accordance with the invention in a longitudinal sectional view, comprising a male edge (22) and a metal body (18). Said male edge contains a part (4) with an external thread, a male thrust surface (24), and a male sealing surface (28). The male thread portion (4) contains a plurality of male thread teeth (6) that run successively along the Y thread root line. The thread axis is parallel to the X axis, which extends in the longitudinal direction.

The tolerance distance of the external or internal pitch corresponds to the length at which the pitch is controlled, that is, the total length of the full-profile thread. A full-profile thread can be defined in contrast to a partial-profile thread, that is, a thread whose height is not full. It is also called a vanishing thread, which refers to a partial thread. For male threaded end (20), the pitch tolerance distance is determined by Dpinmin.

In fig. 5 shows a female end (21) in accordance with the invention in a longitudinal sectional view, comprising a female edge (23) and a metal body (18). Said female edge contains a part (5) with an internal thread covering the thrust surface (25), as well as a female sealing surface (29). The internal thread portion (5) contains a plurality of thread teeth (7) that extend successively along and away from the Y thread root line. The thread axis is parallel to the X axis, which extends in the longitudinal direction.

In fig. 6 is a schematic longitudinal sectional view of a tubular threaded connection (61) in accordance with the prior art, with stresses represented by finite element analysis (FEA). Tubular threaded connection (61) contains a male tubular element (62), containing a part (64) with an external thread, a male sealing surface (28), as well as a male stop (24) and a female tubular element (63), containing a part (65) with internal thread covering the sealing surface (29), as well as the female stop (25). In the case of FIG. 6, the connection contains a threaded axial gap, that is, TAG, 0.250 mm for a connection with an outer diameter (OD) of 139.7 mm. With reference to Table 2 below, the 0.250 mm gap exceeds the TAGmax value specified for a 139.7 mm nominal outside diameter connection.

Dark areas in Fig. 6 correspond to areas of plasticization due to mechanical compression, which can be visualized using finite element analysis (FEA). In fig. 6, two separate areas of plasticization can be observed: the first is the area of the male sealing surface (28), and the second represents two stops: the male (24) and female (25) stops. Plasticization of the stops can be considered normal and expected. However, plasticizing the male sealing surface (28) as opposed to plasticizing the stops is not acceptable and poses a serious risk of leakage or failure.

In fig. 7 is a schematic longitudinal sectional view of a tubular threaded connection (1) in accordance with the invention obtained by finite element analysis. Tubular threaded connection (1) contains a male tubular element (2), containing a part (4) with an external thread, a male sealing surface (28), as well as a male stop (24) and a female tubular element (3), containing part (5) with internal thread covering the sealing surface (29), as well as the female stop (25). The connection in FIG. 7 is different from the connection in FIG. 6 on a thread positioned such that the threaded axial spacing TAG of the connection shown in FIG. 7 is 0.120 mm, that is, less than the TAGmax of the connection. Finite element analysis (FEA) revealed no plasticization of the male sealing surface (28). In the configuration according to the invention, the threaded axial gap TAG is small enough so that the embedded side of the male thread tooth and the internal thread tooth contact each other without reaching the stage of plasticization of the sealing surfaces. Under these conditions, the threads are in sufficient contact to not interfere with deceleration or compensating compression forces. This improves compaction. In this way, the thread plays a supporting role without being damaged, and solves the deterioration problem shown in FIG. 2.

In fig. 8 shows a male tubular element (2) in accordance with the invention, having a longitudinal axis X, comprising a male edge (22), a male thread part (4) and a male stop (24).

The threaded axial spacing TAG is defined relative to the cross-sectional area (A) of the male edge (22) of the PinLipSurface, in other words, the cross-section of the male tubular element on the male edge between the sealing surface and the thrust surface. The threaded axial spacing TAG is less than or equal to the maximum spacing TAGmax such that:

Calculation 4.

TAGmax = a * PinLipSurface + b + (4 * Epcoat) where: ^{0 E} P ^coat Epcoat max a=0.00053;

b=0.14;

- 6 046028 where: PinLipSurface - value of the cross-sectional area of the male edge between the sealing surface and the thrust surface in mm ² ;

a is the value of the correlation slope;

b - value of the intersection point;

Epcoat - the value of the thickness of the anti-corrosion and/or lubricating coating in mm.

The term cross-sectional area (A) of the male edge (22) means the surface limited by the male stop (24) on one side, the profile (31) of the outer surface or side of the thread, the profile (32) of the inner surface opposite the outer surface, and finally limited radially oriented segment (34) and passing through the midpoint of the male sealing surface (28).

The maximum TAGmax distance is determined in relation to the dimensions of the male tubular element (2) or its male end (20), taking into account that the female tubular element (3) or its corresponding female end (21) has dimensions such that the sealing surfaces are in contact after assembly of the male threaded end (20) with the female threaded end (21).

a is the correlation slope value and b is the intercept value of the straight line representing TAGmax as a function of PinLipSurface.

For the sake of simplicity, the applicant has calculated a set of practical values according to the nominal pipe diameter for TAGmax values.

table 2

OD (in mm) Pipe thickness (in mm) TAGmax (in mm) Nipple edge surface (mm ² ) 114.30 12.7 0.166 100.73704 139.70 12.09 0.154 94.9086502 244.48 13.84 0.255 120.720601 355.60 20.62 0.271 187.84287

As shown in the examples in table. 1 and 2, TAGmin and TAGmax values may vary depending on the connection.

In accordance with one aspect of the present invention, the threaded axial gap TAG is between the two values TAGmin and TAGmax such that:

TAGmin < TAGmax

Thanks to this feature, for the same type of connection or dimensions, it is possible to determine a thread axial gap (TAG) corresponding to the minimum threshold value, from which it is guaranteed to compensate for the effect of any thread misalignment arising from the accumulation of pitch errors, while eliminating any risk of loss of sealing characteristics caused by the accumulation of pitch errors.

In fig. 9 illustrates an embodiment in which the present invention comprises a hard or semi-hard coating. The specified coating performs a lubricating and/or anti-corrosion function. This type of coated connection is becoming increasingly common to avoid the use of lubricants during screwing. In fig. 9 shows a tubular threaded connection (1) in accordance with the invention and, in particular, a tooth (6) of an external thread and a tooth (7) of an internal thread in the assembled state, a section view along the longitudinal axis X. The tooth (6) of an external thread contains an external support side (12) and outer embedded side (14). The tooth (7) of the internal thread contains an internal support side (13) and an internal embedded side (15). The outer (14) and inner (15) embedded sides, as well as the outer (12) and inner (14) support sides contain an anti-corrosion and/or lubricating hard coating (10). One way to determine the TAG thread clearance is the difference between the cavity width (LCB) between two internal thread teeth and the external thread tooth width (LP). The specified threaded axial spacing TAG is greater than or equal to the minimum spacing TAGmin such that:

Calculation 5.

TAGmin = IT (min) * (1/2^.^.^ + 1/2 ₊ (4 " Epcoat) '' (Dpinmm) ' (Ddoxmml where: ⁰ < ^E P ^{coat s} Epcoat max where: TAGmin - minimum value threaded axial gap in mm; ITmin - minimum pitch mismatch tolerance value in mm;

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LFpinmin - minimum value of the axial length of the external thread in mm;

LFboxmin - minimum value of the axial length of the internal thread in mm;

Dpinmin - minimum value of the outer pitch tolerance distance in mm;

Dboxmin - minimum value of the internal pitch tolerance distance in mm;

Epcoat - the value of the thickness of the anti-corrosion and/or lubricating coating in mm.

The developments shown in FIG. 3 are applicable to FIG. 9. In this configuration, the Epcoat thickness is multiplied by a factor of 4, which accounts for the 4 coating thicknesses present on the two outer (14) and inner (15) embedded sides, as well as the two outer (12) and inner (13) support sides. The 4*Epcoat parameter in the equation promotes the presence of a larger TAGmin. In this case, Epcoat is the average of the thicknesses of the outer (12) and inner (13) support sides, as well as the outer (14) and inner (15) embedded sides, taken in combination, but the present invention can also offer different thicknesses of Epcoat in depending on the mortgages or supporting sides in question. Epcoat thickness is the average thickness of the coatings on the sides of the threads.

The thickness of the hard coating can increase the contact pressure on the thread flanks, thereby increasing the risk of embrittlement or plasticization. The present invention enables screwing without the additional risk of embrittlement or plasticization of the joint due to the presence of such a coating.

In accordance with a complementary aspect, the maximum thickness of the anti-corrosion and/or lubricating coating Epcoat max (10) is 0.0075 mm. Preferably, the coating (10) has a thickness of from 0.0010 to 0.0075 mm.

Thanks to this feature, a wide variety of solid anti-corrosion and/or lubricant coatings can be included in the configuration, ensuring that any risk of pitch mismatch with a maximum thickness of 0.0075 mm is absorbed.

The anti-corrosion and/or lubricating coating (10) may comprise a layer containing zinc and nickel, which has excellent anti-corrosion and lubricating properties.

The developments shown in FIG. 9 are applicable in whole or in part to a part with external (4) and internal (5) threads when the invention contains a coating (10).

In fig. 10 shows a screw-in curve of a pipe according to the prior art, including the accumulation of unabsorbed pitch error. The method used to ensure correct assembly of connections is to control the torque applied by the clamp as a function of the number of revolutions. The term clamp refers to a powerful self-locking wrench used to grip the male and female components of a connection and apply tightening/loosening torque. By connecting a computer to the load cell on the clamp and the electronic revolution counter, a graph can be generated showing the torque on the vertical axis and the number of revolutions on the horizontal axis, as shown in FIG. 10.

The first part I corresponds to the tightening step in which contact occurs between the threads, more specifically, at least contact between the respective embedded sides of the male (20) and female (21) threaded ends. At this point, there is little resistance for the first few turns until the respective threads begin to touch each other radially. The second part II corresponds to the contact of the male and female sealing surfaces, which leads to the first sharp increase in the curve. Finally, the last part III corresponds to the connection of the thrust surfaces of the tubular elements with external and internal threads, which leads to a sudden increase in torque at small amplitudes of relative rotation of the male and female components relative to each other.

Since it is not possible to achieve the same torque every time two tubular threaded elements are screwed in, there are acceptance limits represented by the two solid screw-in curves in FIG. 10 and 11. Thus, the connection including the accumulation of unabsorbed pitch error by the configuration represented by the dotted curve in FIG. 10 will lead to a shift in the screwing phases, which is visible on the graph with a curve that is outside the acceptance limits. However, at this stage it is too late: the pipe can no longer be used or repaired and is therefore likely to be rejected, resulting in losses.

In fig. 11 shows a dotted screw-in curve for assembling a connection in accordance with the invention, including the accumulation of absorbed pitch error. The threaded axial gap is large enough to absorb any buildup of pitch error. Thus, there is no displacement and therefore the curve fits well within the permissible limits represented by the two solid screwing curves.

In fig. 12 shows a superimposed first male end (20) and a second male end (40), each comprising a male thread portion (4a) and (4b). Each tooth (6) of the external thread contains a supporting (12) and a mortgage (14) outer sides. The male threaded part (4a) of the first end (20), represented by solid lines, does not contain a pitch error, corresponding to the in-plane value or the theoretical value of the minimum value of the pitch

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Claims (3)

outer pitch tolerance in mm Dpinmin. The male threaded portion (4b) of the second end (40), highlighted by dotted lines, thus showing the displacement of the supporting sides, includes the accumulation of pitch error and corresponds to the actual value of Vr. Each of the first (20) and second (40) male threaded ends includes a plurality of thread pitches corresponding to an increasing or decreasing position level n shown in FIG. 12 positions n-1, n, n+1, etc. The term pitch means the distance between two successive outer or inner supporting sides, as defined in ISO 5408. In the context of FIG. 12 steps are determined by successive outer support sides. The theoretical value of Dpinmin corresponds to the value in the plane of the considered collective pitch. By comparing the theoretical value of Dpinmin and the actual value of Vr, it can be noted that the difference occurs due to the offset caused by the accumulation of pitch error. This difference corresponds to the minimum step mismatch tolerance value ITmin. An exemplary embodiment of the configuration in accordance with the invention can be obtained in accordance with the following steps: Machining of the male threaded element and the female threaded end on a CNC lathe. Machining is performed on the male end with a total length of 96.94 mm. The pitch error is controlled along the length Dpinmin = 55.88 mm at the male end. Machining is carried out using a profiled machining insert, this profile being the reverse side of a male threaded recess. The insert width is 2.567 mm, the machining pitch is 5.08 mm. Machining is performed on the female threaded end along a length of 82.98 mm, and the pitch error is controlled along a length of 76.20 mm. Mechanical processing is carried out using a profiled insert with a width of 2.647 mm and a machining step of 5.08 mm. Optionally, the present invention may include the following steps: Sandblasting of the specified threaded elements with brown corundum F80. Application of ZnNi by electrodeposition on 2 threaded elements. Application of chromium III passivation by dipping 2 threaded elements. Apply a lubricant coating by pneumatic spray to 2 threaded elements. CLAIM 1. A tubular threaded connection (1) for drilling, hydrocarbon well production, oil and gas transportation, hydrogen transportation or storage, carbon capture or geothermal energy, containing a male tubular element (2) and a female tubular element (3), each of said male (2) or female (3) tubular elements contain, respectively, a part (4) with an external thread and a part (5) with an internal thread, and one or the other of the part (4) with an external thread or part (5) with internal thread optionally contains an anti-corrosion and/or lubricating hard coating (10), wherein said part (4) with external thread and part (5) with internal thread contain, respectively, at least one tooth (6) of external thread and one tooth (5) internal thread and a threaded axial space (8) TAG, providing in the mounted state a space between the embedded side (14) of said external thread tooth and the supporting side (15) of said internal thread tooth (7), characterized in that said threaded axial The TAG gap is greater than or equal to the minimum TAGmin gap such that: Calculation 6. TAGmin = IT(min) * ( _1/2 ^v / v / (Dpinmin) where: ^{0 E} P ^{coat E} P ^{coat m(,x} + (4. Epcoat) (Dboxmiri) ' g S where: TAGmin - minimum value of thread axial gap in mm; ITmin - minimum pitch mismatch tolerance value in mm; LFpinmin - minimum value of the axial length of the external thread in mm; LFboxmin - minimum value of the axial length of the internal thread in mm; Dpinmin - minimum value of the outer pitch tolerance distance in mm; Dboxmin - minimum value of the internal pitch tolerance distance in mm; Epcoat - the value of the thickness of the anti-corrosion and/or lubricating coating in mm; Epcoat max - the maximum value of the thickness of the anti-corrosion and/or lubricating coating. 2. Tubular threaded connection (1) according to claim 1, characterized in that the pitch mismatch tolerance value is from 0.040 to 0.080 mm, preferably from 0.048 to 0.072 mm. 3. Tubular threaded connection (1) according to any of the previous paragraphs, characterized in that the threaded axial spacing TAG is less than or equal to the maximum spacing TAGmax such that: -