Patent Publication Number: US-2017370162-A1

Title: Tubular component with a helical abutment

Description:
The present invention relates to a tubular component for connecting, by makeup, to an analogous component in order to form a contiguous pipework. Advantageously, the invention is of application in producing a stem formed by drill pipes, heavy weight drill pipes and drill collars, which are regularly fitted together and broken apart. A stem of this type may in particular be used when driven in rotation in order to drill hydrocarbon wells. Alternatively, tubular components of this type may also be used in a drill pipe riser or indeed a riser when operating a well of this type. 
     Each tubular component comprises at least one end element, male or female, which is threaded. In general, a tubular component comprises a male threaded end element and an opposed female threaded end element. The threaded end element is intended to be made up with the complementary threaded end element of another component. When connected, the two end elements of the two components form a connection. 
     The threaded tubular components are connected under carefully controlled loads which comply with requirements as regards tightening and sometimes as regards the seal, which depend on the conditions of use. In general, a threaded end element of a connection comprises at least one axial abutment which is activated at the end of makeup and clamped against a corresponding surface by application of a predetermined makeup torque. The makeup torque applied at the end of tightening is known as the torque on shoulder, as it corresponds to the torque necessary for activation of the axial abutments. 
     When two components are made up one with the other, the application of too low a torque on shoulder, for example as a result of a premature halt to makeup, produces a connection which does not comply with specifications. The risks of uncoupling by jump-out or accidental breakout are then high. Before uncoupling per se occurs, loss of tightness may also occur. Insufficient tightening favours rapid wear of the connections and difficulties when it comes to intentional breakout. 
     The application of too high a torque on shoulder, for example as a result of over-torquing, also results in a connection which does not comply with specifications. Portions of the component are at risk of undergoing plastic deformation and damage as over-torquing commences. The intended cooperation between the various surfaces of each of the components is then no longer guaranteed. The behaviour of the junction becomes difficult to predict. Degradation of this type is difficult to repair. 
     In order to limit these risks, a nominal upper torque on shoulder at the shouldering torque and a lower torque on shoulder at the yielding torque are routinely determined. Adhering to the nominal torque on shoulder and its range of tolerances is a guarantee of satisfactory mechanical strength of the connection under the envisaged conditions of use. Adhering to this range limits the risks of malfunction. The limits to the range of the admissible torque on shoulder vary for each component configuration. The nominal values for such limits depend on the dimensions of the components, and in particular on the thicknesses of the walls which vary as a function of the envisaged applications. 
     In practice, makeup/breakout operations are carried out on-site under difficult conditions, for example on offshore platforms. Actual makeup conditions may be very different from the theoretical conditions in a laboratory. 
     In the applications envisaged by the present invention, a threaded end element of a connection may comprise two axial abutments which are axially separated, respectively inner and outer, which are activated at the end of makeup and clamped against corresponding surfaces by the application of a predetermined nominal makeup torque. The predetermined makeup torque for these connections is increased by doubling the surfaces which are engaged in abutment. 
     Wells to be drilled are becoming ever more complicated and ever longer, and the torque exerted on the upstream tubular components increases with increasing distance between the upstream tubular components and the downstream tubular components. The invention improves the situation by proposing tubular components which can be used to resist higher operational loads by proposing a higher nominal makeup torque than that of existing connections, without increasing either the outer dimensions of the connection nor the weight of the string. Further, another advantage of the invention is that it proposes an end element, in particular an abutment, the integrity of which is maintained throughout its use, and for which the seal against liquids is ensured even after several makeup-breakout operations. 
     For an identical wall thickness, a tubular component in accordance with the invention has at least one abutment the active surfaces of which are more extensive than those of known tubular components. The configuration of the invention means that the local contact pressures are not increased, thereby preventing plastification and guaranteeing that the abutments hold under tension traction and thus remain impervious even in service. 
     With the high makeup torque, the contact pressures on the abutment surfaces of the invention are subjected to loads per unit surface area which are identical to those of conventional annular surfaces or ring surfaces. The makeup torque beyond which plastification phenomena may occur is thus higher. 
     To this end, the invention provides a tubular drill stem component comprising an end element having an axis of revolution and provided with a threading extending about the axis of revolution, the end element being adapted to being connected by makeup onto a corresponding end element of another tubular component provided with a complementary threading, the end element comprising at least one outer abutment arranged so as to come into contact with a corresponding outer abutment of the other component at the end of makeup, in which said outer abutment comprises at least one helical surface having an axis of the helix which coincides with the axis of revolution. 
     In another aspect, the Applicant proposes a connection comprising two end elements of two distinct components as hereinbefore defined. The two components are connected to each other by making up the end element of the first component with the corresponding end element of the second component. 
     The component may have the following optional characteristics, either alone or in combination with each other. 
     In particular, the threading has a thread angle such that the helical surface or surfaces may have a helix angle less than or equal to the thread angle of the threading. Advantageously, the helix angle may be in the range 0.5° to 7°. 
     In particular, a sum of the angular portions about the axis of revolution over which the helical surface extends may be in the range 180° to 360°. 
     As a consequence of the existence of the helical surface, the end element further comprises a circumferential shoulder connected to at least one of the circumferential ends of said helical surface. 
     In particular, this circumferential shoulder may comprise at least one substantially planar surface the plane of which forms an angle with the axis of revolution in the range 0° to 75°. In particular, the circumferential shoulder may comprise at least one substantially planar surface the plane of which may be parallel to the axis of revolution or may coincide with the axis of revolution. 
     In accordance with various embodiments, the circumferential shoulder may be connected to the helical surface via a fillet radius or an inclined plane. In particular, when a fillet radius is present, this may have a radius of curvature in the range 0.5 to 10.0 millimetres. 
     Advantageously, the end element may comprise two abutments, an inner abutment and an outer abutment, each of the two abutments comprising at least one circumferential shoulder. Alternatively, the end element may comprise these two abutments, respectively the inner abutment and the outer abutment, such that only the outer abutment is provided with a helical surface. 
     In particular, the end element may comprise a single helical surface located solely on the outer abutment. 
     Advantageously, the helical surface may be at a distance from the threading; a distance between a threading end and the helical surface may in particular be at least 8 mm. 
     More particularly, the invention also concerns a connection comprising two components in accordance with the invention, in which one of the outer abutment of a component or the corresponding outer abutment of the other component is disposed at a free distal end of its end element. 
     Other characteristics, details and advantages of the invention will become apparent from the following detailed description and accompanying drawings in which: 
    
    
     
         FIG. 1  is a longitudinal partial sectional view of two components in accordance with the invention; 
         FIG. 2  is a perspective view of a male end element of a component in accordance with the invention; 
         FIG. 3  is a perspective view of a variation of a male end element of a component in accordance with the invention; 
         FIG. 4  is a perspective view of a female end element of a component in accordance with the invention, corresponding to that of  FIG. 3 ; 
         FIGS. 5 to 8  are perspective views of variations of a detail of an end element of a component in accordance with the invention; 
         FIGS. 9, 10 and 11  are perspective views of variations of a male end element of a component in accordance with the invention; 
         FIG. 12  is another variation of a male end element, provided with three helical surfaces in accordance with the invention. 
     
    
    
     The drawings and description below essentially contain elements of a specific nature. Thus, they may not only serve to act towards a better understanding of the present invention, but also contribute to its definition if necessary. 
     A first tubular component  1  and a second tubular component  101  are represented in  FIG. 1 . The components  1  and  101  are generally in the form of a body of revolution about an axis of revolution XX. In  FIG. 1 , the components  1  and  101  are aligned with each other. The axes of revolution XX therefore coincide. The direction of the axis of revolution XX is termed the axial direction. 
     In order to facilitate comprehension, the numerical references for the second component  101  are greater by 100. Each of the components  1  and  101  comprises an end element  2  or respectively  103 . Here, the first component  1  comprises a male end element  2  (or pin), while the second tubular component  101  comprises a female end element  103  (or box). The components  1  and  101  each comprise a regular tube portion  9  or  109 . The regular portion  9  of the tube is integral with the male end element  2  and at an opposite end is also integral with a second female end element (not shown) which is identical to the female end element  103 . Similarly, the regular tube portion  109  is integral with the female end element  103  and at an opposite end is also integral with another male end element (not shown) which is identical to the male end element  2 . 
     The regular tube portions  9  and  109  of the two components  1  and  101  are similar to each other. The tubular components  1  and  101  are impermeable in structure and in material. In particular, the tubular components form metallic structures, in particular produced from steel or Inconel. As an example, the grade of the material is of the order of 130 ksi, with a yield strength in the range 120 000 to 140 000 psi; however, it may also be selected from higher grades of about 140 ksi, 150 ksi and 165 ksi, as well as from lower steel grades such as those defined at about 80 ksi or 95 ksi or even 110 ksi. The end elements  2  and  103  may be produced from a material which is identical to or different from that of the tubes  9  and  109 . 
     Here, the end elements, in particular  2  and  103 , have a configuration which conforms with the standard API-7 or API-RP-7G or indeed ISO-10407-1. In variations, the end elements  2  and  103  have a proprietary configuration, for example as marketed under the trademark VAM® Express, or indeed as described in the publications WO-2006/092649 or WO-2012/089305. 
     The regular portion  9  is generally cylindrical in shape and has a length in the range 5 to 15 metres for long components, for example drill pipes, and 1 to 5 metres for short components, for example wear inserts used at the well head. The inner diameter is, for example, in the range 25 to 400 millimetres, while the external diameter is in the range 50 to 500 millimetres. 
     The component  1  may be obtained by friction welding the end elements to each end of a tube forming the regular portion  9 . The same mode of production may be employed for the component  101 . In such cases, the ends of the regular portion  9  may have already been forged, upset or thickened so as to increase the radial surface of the metal. As can be seen in  FIG. 1 , a weld plane  5  or  105  is respectively formed at the junction between the regular tube portions  9  and  109  with the end elements  2  and  103  respectively. Alternatively, the tubular component may be integral, namely without a weld, obtained from a single blank. The regular portions  9 ,  109  are not shown in  FIGS. 2 to 8 . 
     The end elements  2 ,  103  are generally tubular in shape. The end elements  2 ,  103  have an exterior surface  11 , respectively  121 , which is substantially cylindrical. 
     The end elements  2 ,  103  carry an interior surface  17 , respectively  127 , or bore, which is substantially cylindrical. 
     In general, the surfaces of revolution of the components  1  and  101  are substantially concentric with a centre belonging to the axis of revolution XX. The thicknesses of the walls of the components  1 ,  101  are substantially homogeneous in circumference, except at the positions of the end elements. 
     In use, the components  1  are manipulated using rams. The rams will hold the components  1  by means of their end elements  2  or  103 . The end elements  2  and  103  are better suited to withstanding the loads applied, in particular during makeup/breakout operations. In particular, the exterior contact surfaces  11  or respectively  121  locally have a largest exterior diameter intended to be taken up in the jaws of working tongs in order to guarantee the final makeup torque of the connection to be formed. This exterior contact surface is that which will come into frictional contact against the walls of the well during rotation of the drill stem. 
     Reference will now be made to  FIGS. 1, 2 and 3  which represent three embodiments of a male end element  2  of a component  1 . The male end element  2  comprises a substantially tapered exterior surface  12  in which at least one exterior threading known as the male threading is formed. The end element  2  further comprises an end surface  13  and a central surface  16 . The exterior tapered surface  12  is located axially between the end surface  13  and the central surface  16 . The end surface  13  and the central surface  16  are free of any threading. In the example shown, the end surface  13  and the central surface  16  have a substantially cylindrical profile. 
     In the example shown, the tapered exterior surface  12  with the threading comprises a threading having a single-start thread. 
     The end surface  13  connects to a surface  15  extending substantially in accordance with the thickness of the end element  2 , substantially perpendicular to the end surface  13 . This surface forms an inner abutment  15 . The inner abutment  15  defines the free distal end of the end element  2  of the component  1  in the disconnected condition. This inner abutment  15  connects on the inside to an interior surface  17  which is substantially cylindrical. The inner abutment  15  is termed the male inner abutment. 
     The central surface  16  is connected to the exterior contact surface  11  via a surface which extends substantially along a portion of the thickness of the end element  2 . This surface forms an outer abutment  18 . The outer abutment  18  forms an exterior shoulder of the end element  2  of the component  1 . The outer abutment  18  is termed the male outer abutment. 
     Advantageously, at least one of the inner abutment  15  and the outer abutment  18  has a helical surface. In the case in which the end element  2  has a single helical surface, this helical surface is produced on the outer abutment  18 , as was the case with the helical surface  38  of  FIG. 2 . 
     In  FIG. 2 , the helical surface  38  is at a distance from the threading. An axial length D 1  for the central surface  16  which is free of threading may be defined; in particular, this distance D 1  is at least 8 mm and, for example, less than 24 mm. This distance D 1  corresponds to the minimum axial distance along the axis XX between the helical surface  38  and the substantially tapered exterior surface  12  carrying the threading. 
     The helical surface  38  is defined by an axis of the helix which coincides with the axis of revolution XX. The sense of the helix of the helical surface  38  corresponds to that of the threading of the tapered exterior surface  12 . The helical surface  38  has a helix angle which has the reference α (alpha). The threading of the tapered exterior surface  12  has a thread angle with reference β (beta). The helix angle α of the helical surface  38  in this example is equal to the thread angle β of the threading. 
     By definition, the helical surface  38  is not flat. From another viewpoint, the helical surface  38  defines a surface the position of which varies along the axial direction as a function of the angular portion of the component  1 , or angular sector, under consideration. 
     In  FIG. 2 , the outer abutment  18  is connected to the exterior surface  11  via an annular chamfer  20 . 
     In a variation, shown in  FIG. 3 , the end element  2  is shown with two helical surfaces, such that the inner abutment  15  comprises a helical surface  35  and the outer abutment  18  comprises the helical surface  38 . 
     In  FIG. 3 , the helical surface  35  is also at a distance from the threading. An axial length D 2  of the end surface  13  which is free of threading may be defined, this distance D 2  in particular being at least 8 mm, for example less than 24 mm. This distance D 2  corresponds to the minimum axial distance, along the axis XX, between the helical surface  35  and the substantially tapered exterior surface  12  carrying the threading. This distance D 2  also corresponds to the axial distance between the free distal end of the end element  2  and the threaded exterior surface  12 . 
     In the embodiments of  FIGS. 2 and 3 , each angular portion of the helical surface  38  extends in a radial direction, i.e. perpendicular to the axis of revolution XX. In other words, the profile of the helical surface  38 , viewed in a longitudinal section passing through the axis of revolution XX, may be represented by a straight segment orientated in a radial direction. The width of the helical surface  38  is thus substantially equal to the radial distance of the outer abutment  18 . Analogous reasoning applies to the helical surface with respect to the inner abutment  15 . 
     In variations (not shown), the profile of the helical surface  38  may be straight and have a non-zero inclination with respect to a radial direction. In this case, the helical surface  38  has a generally tapered configuration. The width of the helical surface  38  is thus substantially greater than the radial thickness of the outer abutment  18 . In other variations, the profile of the helical surface  38  may be curved, for example concave or convex. The radial width of the helical surface  38  is thus substantially greater than the outer abutment  18 . 
     In the embodiments of  FIGS. 2 and 3 , the helical surfaces  35  and  38  extend over the whole circumference of their respective abutments, i.e. approximately 360°. The helix angle α of the helical surfaces  35  and  38  are substantially identical. In this example, the helix angle α is substantially equal to the thread angle β of the threading of the tapered exterior surface  12 . The helix angle α of the helical surface  38  is in the range 0.5° to 7°, for example. 
     The presence of the helical surfaces  35  and  38  results in the formation of a circumferential shoulder  36  or respectively  39  on each of the abutments  15  and  18 . The two circumferential shoulders may be substantially planar, each forming a plane comprising the axis XX. They may be designed so as to be in the same plane. 
     The outer abutment  18  of the end element  2  thus comprises the circumferential shoulder  39 . The circumferential shoulder  39  extends over an axial position of the end element  2  which is identical to that over which the helical surface  38  extends. When the helical surface  38  is 360°, the circumferential shoulder  39  connects the two circumferential ends of the helical surface  38  one to another. 
       FIG. 5  shows a detail of the circumferential shoulder  36  of the embodiment of  FIG. 3 . The two circumferential ends of the helical surface  35  are aligned in the axial direction, and so here, the circumferential shoulder  36  exhibits a zero circumferential component. In the example of  FIGS. 2 and 3 , the circumferential ends of the helical surface  38  are aligned in the axial direction, with the circumferential shoulder  39  here having a zero circumferential component. In these configurations, the circumferential shoulder  39  defines a plane passing through the axis XX. In particular in  FIG. 3 , the circumferential shoulders  36  and  39  are defined in the same plane. 
     In  FIG. 6 , the circumferential shoulder  36  comprises a substantially planar surface. The plane of the planar surface forms an angle γ (gamma) with the axis of revolution XX. In the embodiments of  FIGS. 2 and 3 , the plane of the respective planar surface of the circumferential shoulders  36  and  39  here is substantially coincident with the axis of revolution XX. The angle γ is thus substantially zero. The planar surface of the circumferential shoulders  36  and  39  extends substantially perpendicular to the helical surfaces  35  and  38 , plus or minus the helix angle α. 
     In the example of  FIG. 2 , the circumferential shoulder  39  is connected to both of the circumferential ends of the helical surface  38  via sharp borders or edges. This is also the case in  FIG. 3  for the circumferential shoulders  36  and  39 . 
       FIGS. 6, 7 and 8  show variations of the helical surfaces. To make these variations more legible, they are shown on the inner abutment  15 . Clearly, each of the variations may also be applied to the embodiment in which the helical surface is on the outer abutment  18  as shown in  FIGS. 9, 10 and 11 . These variations are primarily distinguished from the embodiment of  FIG. 3  in that the helical surface  35  extends over an angular portion of less than 360°. The two circumferential ends of the helical surface  35  are out of alignment in the axial direction. The circumferential shoulder  36  linking them has a non-zero circumferential component. The circumferential shoulder  36  extends over an angular portion of several degrees, for example between 1° and 15°. 
     In the variations of  6 ,  7  and  8 , the profile of the surfaces of the circumferential shoulder  36 , viewed in a longitudinal section passing through the axis of revolution XX, may be represented by straight segments orientated in a radial direction. As was the case for the helical surface  35 , in a variation the profile of the circumferential shoulder  36  is straight and has an inclination with respect to a radial direction. In other variations, the profile of the surfaces of the circumferential shoulder  36  may be curved, for example concave or convex. 
     In the variation of  FIG. 6 , the circumferential shoulder  36  comprises a substantially planar surface. The plane of the planar surface forms an angle γ with the axis of revolution XX. Here, the angle γ is non-zero, for example in the range 0° to 75°. As was the case with  FIG. 2 , the circumferential shoulder  36  is connected to both of the circumferential ends of the helical surface  35  via sharp borders or edges. 
     In the variation of  FIG. 7 , the circumferential shoulder  36  comprises two fillet radii, one being concave and the other, convex. The fillet radii each have a radius of curvature, respectively with references R 1  and R 2 . The connections between the circumferential shoulder  36  and the helical surface  35  do not have a sharp border or edge. In a variation, not shown, the circumferential shoulder  36  might not have a planar surface, so that the fillet radii are connected to each other via a point of inflexion in a manner such that the circumferential shoulder  36  forms a substantially continuous link between the two circumferential ends of the helical surface  35 . Here, the radii of curvature R 1  and R 2  are substantially equal. The radii of curvature R 1  and R 2  are in the range 0.5 to 10 millimetres, for example. 
     In the variation of  FIG. 8 , the circumferential shoulder  36  comprises two substantially planar, mutually intersecting surfaces. A first plane  36 ′ forms a zero angle γ with the axis of revolution XX. In contrast to the case of  FIG. 3 , the planar surface is connected to one of the two circumferential ends of the helical surface  35  via a second plane  36 ″ in the form of a chamfer, here at substantially 45°. Here, the chamfer is provided on the side of the concave connection with the helical surface  35 . Instead of or in addition, a chamfer may be provided on the side of the convex connection with the helical surface  35 . 
     In other variations, the helical surface  35  extends over a little more than 360°, i.e. one turn plus a few degrees, for example between 361° and 365°. The circumferential end portions of the helical surface  35  are then slightly superimposed in the axial direction at a singular angular portion of the component  1 . The circumferential shoulder  36  is then shaped into a concavity connecting the two circumferential ends of the helical surface  35  with each other. 
     In a variation of  FIGS. 9, 10 and 11  (not shown), the inner abutment  15  might not have a helical surface, while the inner abutment is provided with a single helical surface in one of the variations. 
     In other embodiments, the abutment  15  comprises a helical surface  35  which extends over an angular portion which is significantly less than 360°, for example less than 270°, or more preferably less than 180° or less than 90°. 
     In the cases in which the helical surface extends over an angular portion of significantly less than 360°, the abutment then comprises said single helical surface, a single circumferential shoulder and the remaining angular portion of the abutment which then defines a surface in the form of a portion of a ring. The profile of the surface in the form of a portion of a ring, viewed in longitudinal section, may be planar and parallel to a radial direction, planar and inclined with respect to a radial direction or indeed curved, for example convex or concave. The abutment  18  comprises the surface in the form of a portion of a ring, the helical surface  38  and the circumferential shoulder  39 , in succession along the circumference. In this case, the circumferential shoulder  39  connects a circumferential end of the helical surface  38  to a circumferential end of the surface in the form of a portion of a ring. 
     In a variation,  FIG. 12 , the abutment  18  comprises at least two helical surfaces  38 . The abutment  18 , as a consequence, comprises as many circumferential shoulders  39  as there are helical surfaces  38 . The abutment  18  comprises, in succession along the circumference, a first helical surface  38 ′, a first circumferential shoulder  39 ′, a second helical surface  38 ″, and a second circumferential shoulder  39 ″. In the example of  FIG. 12 , the inner abutment  15  also has a helical surface  35 , and so it constitutes an embodiment with three helical surfaces. 
     In accordance with the invention, the presence of N helical surfaces may be combined with N planar surfaces in the form of a portion of a ring. The abutment then comprises a succession of N ensembles along the circumference, constituted by a helical surface, a surface in the form of a ring and a circumferential shoulder. 
     The sum of the angular portions over which the N helical surfaces extend is, for example, in the range 180° to 360°. 
     Each characteristic, embodiment, variation and combination which derives from the description above in respect of the abutment  15  can be transposed to the abutment  18  and vice versa. Furthermore, the first end element  2  of a component  1  may comprise: 
     i) an abutment  15  in accordance with one of the embodiments described above on the inside and an abutment with configuration which is known per se on the outside; 
     ii) an abutment  18  in accordance with one of the embodiments described above on the outside and an abutment with configuration which is known per se on the inside; 
     iii) a combination of an abutment  15  in accordance with one of the embodiments described above on the inside and an abutment  18  on the outside, the abutments  15  and  18  being analogous; or 
     iv) a combination of an abutment  15  in accordance with one of the embodiments described above on the inside and an abutment  18  in accordance with one of the embodiments described above on the outside, the abutments  15  and  18  having different configurations. 
     The circumferential shoulders  36  or respectively  39  may be disposed in the same angular portion of the component  1 , as seen in  FIG. 3 , or be offset with respect to each other. 
     Reference will now be made to  FIGS. 1 and 4 , representing two embodiments of a female end element  103  of a component  101 . The female end element  103  of  FIG. 4  corresponds to and matches the shape of the male end element  2  of the component  1  of  FIG. 3 . Because the shapes match, at the very least it is to be expected that the inner abutment  15  and outer abutment  18  can be placed in sealing engagement over 360° with the corresponding surface carried by the female end element  103 , and that the threaded portions can be engaged together. 
     The female end element  103  comprises a substantially tapered interior surface  122  in which an interior threading is provided. The end element  103  further comprises an end or distal surface  126  and a central or proximal surface  123 . The threading of the interior tapered surface  122  is located axially between the end surface  126  and the central surface  123 . The end surface  126  and the central surface  123  are free of a threading. The end surface  126  and the central surface  123  are substantially cylindrical and match the shape of the central surfaces  16  and the end surfaces  13  of the male end element  2 . A space is provided between these respective cylindrical portions in order to form a backflow zone for grease deposited on the threads; this grease might have been deposited in a quantity which is larger than the residual interstitial space provided between the threads at the end of makeup. 
     The end surface  126  has a diameter which is larger than that of the central surface  123 . The threading of the interior tapered surface  122  is located radially between the end surface  126  and the central surface  123 . 
     During connection, the axis of makeup corresponds to the axis of revolution XX. The sense of makeup is imposed by the sense of the complementary threadings of the exterior  12  and interior  122  tapered surfaces. The embodiment of  FIGS. 3 and 4  comprises threadings with a conventional makeup sense, i.e. the end elements  2 ,  103  have right handed threads. 
     The central surface  123  and the interior surface  127 , both substantially cylindrical, are connected to each other via a surface extending substantially along a portion of the thickness of the end element  103 . This surface forms an abutment  125 . The inner abutment  125  forms an interior shoulder of the end element  103  of the component  101 . 
     The end surface  126  and the exterior surface  121 , both substantially cylindrical and concentric, are connected one to the other via a surface extending substantially along the thickness of the end element  103 . This surface forms an outer abutment  128 . The outer abutment  128  defines the free distal end or terminal end of the end element  103  of the component  101  in the uncoupled state. 
     Because of their respective radial positions, the inner abutment  125  may be termed the female inner abutment, while the outer abutment  128  may be termed the female outer abutment. 
     The inner abutment  125  of the end element  103  of the component  101  corresponds to the inner abutment  15  of the end element  2  of the component  1 . The shape of the abutment  125  matches that of the abutment  15 . The abutment  15  and the abutment  125  are arranged so as to come into clamping contact one against the other at the end of makeup, and so as to obtain, at all points of the inner abutment  15  facing the abutment  125 , a sufficient contact pressure to ensure a seal against fluids, at least to liquids. 
     The outer abutment  128  of the end element  103  of the component  101  corresponds to the outer abutment  18  of the end element  2  of the component  1 . The shape of the abutment  128  matches that of the abutment  18 . The abutment  18  and the abutment  128  are arranged so as to come into clamping contact one against the other at the end of makeup, and so as to obtain, at all points of the outer abutment  18  facing the abutment  128 , a sufficient contact pressure to ensure a seal against fluids, at least to liquids. 
     In a connection obtained when the two components  1  and  101  are connected one with the other by makeup, the end element  2  of the first component  1  corresponds to the end element  103  of the second component  101 . The N helical surfaces  35 , respectively  38 , are homologues of the N helical surfaces with references  145 ,  148  respectively and the N circumferential shoulders  36  or respectively  39  are homologues of the N circumferential shoulders  146 , respectively  149  provided on the end element  103 . 
     In  FIG. 4 , the helical surface  148  is distant from the threading. The end surface  126  which is free of a threading covers an axial distance D 3  along the axis XX, distance D 3  being not necessarily equal to the axial distance D 1 . This axial distance D 3  also corresponds to the distance between the free distal end of the end element  103  and the threaded interior tapered surface  122 . is This non-zero axial distance D 3  is at least 8 mm and, for example, less than 24 mm. 
     The threadings of the exterior  12  and interior  122  tapered surfaces are complementary. 
     Here, the threadings of the exterior  12  and interior  122  tapered surfaces have a single thread. In a variation, the threadings comprise several threads, for example two, three or four. These are known as multi-start threadings. The threadings have a constant pitch. 
     The operation for connecting the two components  1  and  101  will now be described. In the example of  FIG. 1  or  FIGS. 3 and 4 , the male end element  2  of the first component  1  is connected together with the female end element  103  of the second component  101 . This is equivalent to connecting the male end element (like  2 ) of the second component  101  with the female end element (like  103 ) of the first component  1 . Each of the surfaces of the first component  1  mentioned above can then cooperate with a corresponding surface of the second component  101 . During an uncoupling operation, i.e. breakout, the following events and their order are reversed. 
     Before connection, the components  1  and  101  are aligned one with the other such that their axes of revolution XX coincide and the male element  2  of the first component  1  is disposed facing the female end element  103  of the second component  101 . 
     At the start of connection:
         the male end element  2  is partially inserted into the female end element  103  by means of a translational movement along the axis of revolution XX to bring the components  1 ,  101  towards each other;   using a screwing movement, the threading of the exterior tapered surface  12  and the threading of the interior tapered surface  122  come into engagement with each other.   At the end of screwing up:   the exterior surfaces  11  and  121  are substantially in the extension of each other in the axial direction and are drawing closer to each other;   the interior surfaces  17  and  127  are substantially in the extension of each other in the axial direction and are drawing closer to each other;   the abutment  15  comes into contact against the abutment  125 . In other words, the inner abutments  15  and  125  come into contact with each other;   the abutment  18  comes into contact against the abutment  128 . In other words, the outer abutments  18  and  128  come into contact with each other;   the N helical surfaces  35  come into contact against the N helical surfaces  145 . In other words, the helical surfaces  35  and  145  come into contact in pairs;   the N helical surfaces  38  come into contact against the N helical surfaces  148 . In other words, the helical surfaces  38  and  148  come into contact in pairs;   the N circumferential shoulders  36  approach each other facing the N circumferential shoulders  146 . In other words, the circumferential shoulders  36  and  146  approach each other in pairs;   the N circumferential shoulders  39  approach each other facing the N circumferential shoulders  149 . In other words, the circumferential shoulders  39  and  149  approach each other in pairs.       

     At the end of tightening:
         the exterior surfaces  11  and  121  form a quasi-continuous exterior surface passing from one component  1 ,  101  to the other;   the interior surfaces  17  and  127  form a quasi-continuous exterior bore passing from one component  1 ,  101  to the other;   the abutment  15  is in clamping contact against the abutment  125 , which means that a large makeup torque can be applied;   the abutment  18  is in clamping contact against the abutment  128 , which means that a large makeup torque can be applied;   the circumferential shoulders  36  and  146  are in contact or almost in contact;   the circumferential shoulders  39  and  149  are in contact or almost in contact.       

     The abutments in accordance with the invention comprising at least one helical surface have a larger active surface than abutments constituted by a surface in the form of a planar ring perpendicular to the axis of revolution XX as is known in the prior art. Shaping helical surfaces, for example by machining, into the planar surfaces of a tubular component means that the load transmission surface can be increased. The radial dimensions of the end element, such as the internal and external diameters and the thickness of the tubular wall, remain unchanged. The risks of malfunction in use and the difficulties during breakout operations are reduced. 
     As an example, for an embodiment in accordance with  FIG. 3  with helical surfaces respectively formed on the outer abutment and the inner abutment, the following results are obtained for a connection with a single-start thread in the threaded zone: 
                                                 Nominal makeup   Gain due to       External       torque for a   presence of two       diameter of   Helix angle α of   connection   helical surfaces 35       tube 9 and   helical surfaces   free of a   and 38/nominal       109   (degrees)   helical surface   makeup torque                  73.02 mm   2.1566°   8 135 N · m   +3.77%       (2⅞ inch)       (6 000 ft · lbs)       101.6 mm   1.3103°   38 505 N · m   +2.29%       (4 inch)       (28 400 ft · lbs)       168.27 mm   0.7309°   130 294 N · m   +1.28%       (6⅝ inch)       (96 100 ft · lbs)                    
and the following results with the same configuration with two helical surfaces, but in this case provided with a double-start thread in the threaded zone:
 
     
       
         
           
               
               
               
               
             
               
                   
               
               
                   
                   
                 Nominal makeup 
                 Gain due to 
               
               
                 External 
                   
                 torque for 
                 presence of two 
               
               
                 diameter of 
                 Helix angle α of 
                 a connection 
                 helical surfaces 35 
               
               
                 tube 9 and 
                 helical surfaces 
                 free of a 
                 and 38/nominal 
               
               
                 109 
                 (degrees) 
                 helical surface 
                 makeup torque 
               
               
                   
               
             
            
               
                 73.02 mm 
                 4.3071° 
                 8 135 N · m 
                 +7.53% 
               
               
                 (2⅞ inch) 
                   
                 (6 000 ft · lbs) 
               
               
                 101.6 mm 
                 2.6192° 
                 38 505 N · m 
                 +4.57% 
               
               
                 (4 inch) 
                   
                 (28 400 ft · lbs) 
               
               
                 168.27 mm 
                 1.4615° 
                 130 294 N · m 
                 +2.55% 
               
               
                 (6⅝ inch) 
                   
                 (96 100 ft · lbs) 
               
               
                   
               
            
           
         
       
     
     The higher the pitch of the thread, the larger may be the helix angle, and as a consequence the beneficial effect on the improvement of the nominal makeup torque may be obtained. 
     It will be noted that advantageously, the gain in terms of the final makeup torque is larger when the thread is multi-start. Because the thread pitch is greater when there are more thread starts, increasing the thread angle means that an increase in the helix angle can be obtained. 
     It will also be noted that another significant advantage can be obtained on the improvement in gains on the small diameters of tubular components, often disposed at the very bottom of the well at a long distance from the head of the drilled well and on which it is hardest to generate high makeup torques. 
     The distance separating the circumferential shoulders  39  and  149  on the outside is visible from the outside of the connection. This can therefore constitute a visual indicator to operators monitoring the quality of makeup. 
     When the circumferential shoulders  39  and  149  and if appropriate  36  and  146  come into contact, the reactional force opposing makeup increases abruptly. The circumferential shoulders  36  and  146  or respectively  39  and  149  then form circumferential abutments to stop makeup. The torque necessary to continue makeup increases abruptly. This abrupt increase is readily detectable by makeup tools equipped with dynamometric sensors. Makeup can be stopped before over-torquing occurs. Stopping makeup when an abrupt increase in the torque is detected may be automated. The risks of damaging the end elements such as  2  and  103  of the components  1 ,  101  of the connection are reduced. 
     The invention is not limited to the examples of components and connections described above, given solely by way of example, but it encompasses any and all variations that the skilled person may envisage in the context of the claims below.