FR2489196A1 - METHOD FOR JOINING WITH CIRCONFERENTIAL WELDING OF TWO COAXIAL ELEMENTS AND LATERAL POCKET MANDREL OBTAINED BY SUCH SOLDER - Google Patents

Abstract

THE INVENTION RELATES TO A CIRCUMFERENTIAL WELDING PROCESS FOR JOINING TWO TUBULAR ELEMENTS. THE PROCESS ESSENTIALLY CONSISTS OF PREPARING THE ELEMENTS 20A, 20B BY DRESSING OPERATIONS, LAMING CHANFREINING, SO AS TO PROVIDE AN EXTERNAL NOTCH 21 AT THE ASSEMBLY SITE AND THEN IN POINT THE ASSEMBLED ELEMENTS, IN INTERVALS OF THEIR PERTOURS. THEN WELD THEM BY MAKING SEVERAL CIRCUMFERENTIAL WELDING PASSES FROM THE BOTTOM OF THE NOTCH AND CONTINUING UNTIL ITS OVERFILL. THE PROCESS IS APPLIED IN PARTICULAR TO THE MANUFACTURING OF CHUCKS WITH A SIDE POCKET USED IN TECHNIQUES RELATING TO OIL WELLS.

Description

Z489196

  The invention relates to gas injection devices for emulsion lightening of the oil column, or "gas-lift" devices, and more particularly to lateral pocket mandrels intended for wells produced by gas-lift techniques. 'gas relief or' gas-lift ', as well as

  that a method of manufacturing these side pocket mandrels

  rale. In general, the lateral pocket mandrels comprise elongate tubular bodies, one side of which has a window in which a body of

  lateral pocket housing so that the bore of the housing

  placed inside the mandrel to accommodate flow control devices, while part of the

  body of housing appears at the window and presents

  side communication functions allowing the flow of the

  fluid between the bore of the housing and the outside of the mandrel.

  At least a part of such an embodiment,

  longitudinally to the mandrel, must have welds. Examples of such embodiments are described in U.S. Patent Nos. 2,824,525, 2,948,341, 3,412,806, 3,666,012, 2,942,671, 3,040,814, and US Pat. 3,606,393, 3,727,684, 3,741,299, 3,827,489, 3,994,339, 4,106,563, 3,802,503, 3,827,490, 4,030,543 and 4,106,564, n0. 3,807,498, n0 Re. 28,870, 4,031,954, 4,135,576,

  Nos. 3,807,499, 3,874,445, 4,034,806, and 4,146,091.

  Some side pocket mandrels have

  end-to-end circumferential welds joining

  adjacent tubular Examples of such welds are described in United States patents

  Nos. 3,788,397, 3,827,490, 4,135,576 and 4,146,091.

  However, these circumferential welds are simply butt welds joining tubular elements

adjacent, arranged end to end.

  Some side pocket mandrels have deflection members or baffles that rise above the bore of the housing and are intended to deflect normal well tools passing through the mandrel to return them.

- 2489196

  2. in the main flow channel to avoid the risk of placement on or in the pocket of the side pocket, while accepting and even guiding a flow control device in the housing, which facilitates his installation. Some of these deflectors are made in one piece with the body of the housing and some others are welded on the upper end of the body. Most deflectors which are thus fixed to the body of the housing tend to lengthen the window in which the housing is welded by a longer cord, this additional length being added

  to the longitudinal dimension of the weld.

  Many failures have appeared over the many years of use of these mandrels. Most originate from longitudinal welds

  of structure. Most weld defects appear

  in the longitudinal part of the weld. The term "structural weld" as used herein refers to welds or welded joints that form part of the mandrel-side pocket structure. These structural welds are subjected to stresses generated in the mandrels as a result of forces applied to the mandrels under the effect of tensile, compressive or torsional loads.

  and they are subject to pressures inside.

  and outside the mandrels. A defect of such a weld causes at least one leak in the mandrel. Therefore, the term "structural welding" used in this

  memory also refers to plug welds.

  The occurrence of a defect in such welds is easier to understand in chucks having a

  non-circular straight section. Such mandrels are not

  Those having an oval shape or a flattened shape have been known for a long time and during the last ten to fifteen years a very large proportion of the mandrels used comprise non-circular mandrels. These are more desirable than the circular chucks, as two of these non-circular chucks may be placed side by side or may move each other in a casing of smaller diameter wells, all else being equal. Alternatively, non-circular mandrels of larger size may be used in double wells

  for certain given dimensions of casings.

  When lateral pocket mandrels, and in particular non-circular mandrels with longitudinal structural welds made in their walls, are subjected to high internal or external pressures, the side walls tend to expand or contract, following the case. This expansion or tightening movement of the mandrel wall shows very high stress concentrations in the welds

  longitudinal. It is extremely difficult, even impossible

  in such locations, welds which <1) do not have a notch on the inner side where the inner wall of the mandrel joins the outer wall of the housing body, and (2) have a full penetration. Therefore, longitudinal structural welds are weak points in such mandrels and they cause early failures.

  under severe or even normal conditions.

  In addition, many side pocket mandrels have deflectors attached thereto by means of plug welds. In a similar manner, many mandrels include orientation sleeves for

  guide decentering tools, often focused on

  the mandrel by plug welds. Plug welds, which are often used in the manufacture of side pocket mandrels, sometimes appear in certain patents such as the United States patent.

No. 3,827,490.

  Plug welds cause many failures. Since these welds are made by welding a workpiece such as a deflector or an orientation sleeve on the inner wall through a hole in the wall of the mandrel, this hole resembles a window and at least a portion the weld surrounding the window is oriented longitudinally with respect to the

2489 1 9

4.

  mandrel. Therefore, it is believed that the defects appear

  on plug welds for the same reasons as defects in windows. Although the hole for making the plug weld is smaller than the window used for making the window welds, the notch effect presented by the

welding is substantially the same.

  U.S. Patent No. 3,606,393

  describes a housing body made in such a way as to be

  Heavily heavy to strengthen the window area and reduce the risk of weld failure, the increased mass

  of the material used in the constitution of the body of the lodge-

  being intended to prevent any warping resulting from welding. However, the notch effect still exists, as well as bending of the wall under the effect of pressure in case of bursting or collapse, and failures

are always present.

  The warping of the mandrel under the effect of

  also poses a problem in the manufacture of side pocket mandrels. This is obviously due to the fact that the hot filler metal shrinks with cooling. The shrinkage largely depends on the amount of metal deposited. Therefore, the connection welds of great length

  axial result in greater warpage than the result

  so much shorter welds. When these welds

  connection are not opposed to each other, but

  on one side of the mandrel, as they are generally

  in the case of a side window, in particular a

  long and narrow window, warping can be considered

maple.

  Constraints generated in the body of

  chuck by removing the connection welds can

  destroy the chuck, but they can be removed by heating the entire chuck during

  a process known as stabilization annealing.

  However, this method does not eliminate warping and the mandrel must be straightened by bending in the opposite direction to that

  warping. Following this operation of

2489,196

  5. The chuck has some residual internal stresses, but it is relatively

more acceptable than before.

  It should be noted that, although a certain level of stress is acceptable in a mandrel, it would be ideal to eliminate these constraints completely because they

  tend to favor certain corrosion processes.

  U.S. Patent No. 3,086,593 discloses a check valve disposed in the flow channel passing through a gas-lift valve or gas drain valve which is installed in the off-center housing of a mandrel. lateral pocket to prevent any backflow into this

  channel. Such check valves are commonly used.

  Similar check valves are incorporated in devices which in themselves constitute check valves

  retained, but which are not gas drainage valves.

  When removed from the housing, these flaps open the lateral openings of the housing so that the

  Fluids can flow freely in both directions.

  A prior art drawing, ie, Drawing No. 21100134 of Engineering Corporation, PO Box 34 380, Dallas, Texas 75234, USA, shows a check valve disposed in a flow channel which communicates directly with the lower end of the off-center housing of a lateral pocket mandrel. This check valve is not removable and so it remains constantly active, even when the housing bore is free. However, the applications of this type of side pocket mandrel are very limited because such a mandrel is not compatible with the

  gas-lift valves or conventional gas drainage valves.

  In this type of mandrel, the lower end of the housing bore communicates with the outside of the mandrel; in conventional mandrels, the lower end of the housing bore communicates with the main bore of the mandrel. In conventional gas drainage valves for side pocket mandrels, the lighter gas enters the side of the valve and exits at its lower end so that

  pass through the lower part of the housing bore.

  6. In the conventional side pocket mandrel, the bore of the housing is always drained and the gas drainage valves

  or gas-lift valves can be installed in this

  wise without difficulty. In mandrels where the lower end

  the bore of the housing communicates with the outside of the mandrel and a check valve is disposed in this communication passage, as in the case of the aforementioned drawing No. 2110 134 of Otis Engineering, liquids can accumulate in the bore of the housing and the check valve may prevent their drainage, so that the installation of gas drainage valves or other devices may be difficult or impossible as a result of

presence of these liquids retained.

  In the prior art, there is no lateral pocket mandrel whose lateral orifice contains a check valve, this lateral orifice communicating directly with the bore of the housing at a point situated between its ends.

  that is to say in the middle, where devices can realize

  be a shutter above and below this hole

-lateral. -

  The invention eliminates the problems and inconveniences

  mentioned above by the use of side pocket mandrels and by a method of manufacturing these mandrels to completely eliminate the structural connection longitudinal welds, including the

  window welds and plug welds, and mini-joints

  bending and straightening, this process allows

  so much to get a product manufactured-easily, stronger than products made so far and less prone to failures. The invention also solves the problem of check valves by placing check valves in the side holes of the mandrels to prevent the

  backflow through these side vents.

  The invention thus relates to lateral pocket mandrels whose opposite ends comprise elements

  allowing them to be mounted in a well column.

  Each mandrel comprises a main section of machined body in one piece, and a top section of body

2489,196

7.

  connected to the main section by a circumferential weld-

  tial. The main body section has a full opening main bore and a housing housing bore extending along this main section, the upper section of the body having a belly or bulge that delimits a space above the bore housing for the operation of a decentering tool. These mandrels may include, if desired, elements for orienting and actuating off-centering tools, as well as deflectors for directing flow control devices to the bore of the housing and directing ordinary well tools to the main bore. The invention also relates to a method of manufacturing such side pocket mandrels, including welding body sections.

  tubular to each other. The invention also relates to

  the side pocket mandrels made by these methods, some of these mandrels also having a check valve device for flow control in

  the lateral holes of the mandrels.

  The invention therefore relates to an improved mandrel

  A body pocket section comprises a main body section formed integrally and traversed by a full opening main bore, a housing bore being machined along the main bore in this body section. The latter has elements enabling it to be connected to a well column and is joined by a circumferential weld to an upper body section also having elements allowing it to be connected to a well column. An orientation sleeve is welded or brazed so as to surround the main channel of the mandrel, the welding being effected by passing through the open upper end of the mandrel, the brazing being carried out in an oven. An orientation device is formed in the bore

  main and made in one piece with the main section

  cipal of the body. A deflector or deflector is welded to the inner wall of the upper section of the body before the main body section is welded to this upper section. The mandrel therefore comprises a main body section 8. made in one piece and traversed by a full opening main bore. A housing bore is machined in the main section, along the main bore, and upper and lower body sections are joined by circumferential welds at the upper and lower ends of the main section, these upper and lower sections of the body having fasteners to a well column. An orientation mandrel is welded or brazed in the upper section

  of the body, this welding being carried out by passing through the

  the open top of the mandrel and the brazing being carried out in an oven. An orientation sleeve is welded to the interior of the lower section of the body, the welding being performed by the open top end of the lower section of the body before this section is

  welded on the main section of the body.

  The invention also relates to a method for manufacturing an improved lateral pocket mandrel, comprising forming a main section of a body in one piece by machining a main bore, with a total opening, in this section, machining a housing bore in the main section, along the main bore, and making, on the lower end of this section, an element allowing the latter to be connected to a well column, to perform a upper body section crossed by a main canal and having a belly or

  a space above the housing bore and allow

  both the operation of a decentering tool, the upper end

  upper section of the body having an element allowing said section to be connected to a well column, and to join the upper section to the

  main section by a circumferential weld.

  The lower part of the main section of the body is made separately by forming a lower body section through which a main channel passes and whose lower end has an element allowing this lower section to be connected to a column of wells, the lower section being joined to the lower end of

  the main section by a circumferential weld.

  9. The method of manufacturing a lateral pocket mandrel according to the invention also consists in producing a

  orientation sleeve which has an orientation opening

  having a stop shoulder at its upper end.

  the sleeve having a guide surface below the opening and facing upwardly towards said opening. The orientation sleeve is introduced in

  the upper part of the upper section of the body,

  above the belly, and it is welded in this upper part

  upper, or brazed, the welding being performed by the open upper end of the upper section of the body, and brazing being performed

in an oven.

  The invention also relates to a method of manufacturing an improved side pocket mandrel, comprising providing an orientation sleeve having an orientation aperture and a guide surface below said opening and facing upwards. and toward said opening. The orientation sleeve is introduced into the lower section of the body and is welded into this

  section in position, so as to surround the main channel

  pal, the welding being performed by passing through an open end, preferably the open end of the lower section of the body before the latter is welded to the

main section of the body.

  The invention also relates to a method of manufacturing a lateral pocket mandrel, comprising producing a deflection device and welding this device on the inner wall of the upper section of the body, in an appropriate position above the bore the housing, so as to deflect common well tools from the housing to the main channel when these tools down to the deflection device, the non-structural welding being performed by the open lower end of the upper section of the body before it is welded to the

main section of the body.

  The invention therefore relates to a lateral pocket mandrel of the type described above, comprising a device with a check valve for preventing any backflow through the lateral orifices of this mandrel, even when the bore of the off-center housing does not contain any device. flow control, the lateral orifices providing communication between the outside of the mandrel and the bore of the housing, between

its ends.

  The invention also relates to a cartridge type check valve assembly for inexpensive side pocket mandrels to be manufactured and easy to set up and remove. The check valve assembly can be easily converted from a mode in which it prevents outflow to a mode in which it prevents

  all inward flow, and vice versa.

  The invention also relates to a method for joining two tubular elements such as body sections of a side pocket mandrel arranged end to end,

  the junction being made by means of a circumferential weld

  A full-penetration, high-strength compound does not obstruct or reduce the bore section of these tubular elements as a result of the fabrication of this weld. The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting examples and in which: FIGS. 1-A and 1-B, taken together, represent in longitudinal section one of the preferred embodiments of FIG. the invention; Figure 2 is a section on line 2-2 of Figure 1-B; Figure 3 is a section on line 3-3 of Figure 1-B; FIG. 4 is an elevation of the sleeve

  orientation used in the lateral pocket mandrel

  shown in Figures 1-A and 1-B; Figure 5 is a section on the line 5-5 of Figure 1-B; Figure 6 is a partial longitudinal section showing an alignment ring placed between flush surfaces formed on the ends of adjacent sections of bodies ready to be welded to each other; FIG. 7 is a sectional section, similar to that of FIG. 6, showing the body sections of FIG. 6 after they have been welded to each other, the outer surface of the weld being ground so that flush with the outer surface of the body sections, this view also showing the aligned alignment ring during this operation; Figure 8 is a partial sectional view, similar to that of Figure 6, showing flush surfaces formed on the ends of adjacent sections of bodies joined to each other and ready to be welded; - Figures 9-A and 9-B, taken together, represent in longitudinal section another preferred embodiment of the invention;

  - Figures 10-A and 10-B, considered together

  ble, represent in longitudinal section another preferred embodiment of the invention;

  - Figure 11 is a section along line 11-

11 of Figure 10-B;

  - Figures 12-A and 12-B, considered together

  ble, represent in longitudinal section another preferred embodiment of the invention; Fig. 13 is an elevation of the orientation sleeve used in the side pocket mandrel of Figs. 12-A and 12-B;

  - Figure 14 is a section along line 14-

14 of Figure 12-B;

  - Figure 15 is a section along the line 15-

  of Figure 12-B; FIG. 16 is a diagrammatic elevation showing a dual gas-lightened well installation using side pocket mandrels according to the invention as well as check valves; Fig. 17 is an elevation, with partial longitudinal section, showing a side pocket mandrel similar to that shown in Figs. 12-A and 12-B, but equipped with check valves; 12.

  - Figure 18 is a section along line 18-

  18 of Figure 17; FIG. 19 is a fragmentary section, on an enlarged scale, of a detail of FIG. 18 showing one of the check valves controlling one of the lateral orifices of the lateral pocket mandrel; FIG. 20 is a partial elevation showing a check valve housed in one of the side ports of the side pocket mandrel of FIG. 17;

  FIG. 21 is a longitudinal section exploded

  tee of the check valve assembly of Fig. 19;

  FIG. 22 is a longitudinal section through

  showing an installation of injection wells

  gas lighter chucks according to the invention, equipped with check valves; - Figures 23-A and 23-B show, together and in elevation with partial longitudinal section, a side pocket mandrel similar to that shown in Figures 9-A and 9-B, but equipped with check valves;

  - Figure 24 is a section along line 24-

24 of Figure 23-B

  FIG. 25 is a longitudinal partial section.

  enlarged dinal of a detail of Figure 24,

  showing a variant of a check valve assembly

  felt in the closed position in which the valve prevents any flow from the outside of the lateral pocket mandrel towards the bore of the housing; FIG. 26 is a cross-section similar to that of FIG. 25, showing the check valve assembly and an inverted backing disc, so as to prevent any flow.

  at the outlet of the housing bore of the lateral pocket mandrel

  rale; - Figure 27 is a partial longitudinal section, similar to that of Figure 8, showing a variant of the shape of the outer groove of the weld; - Figure 28 is a longitudinal section

  partial, similar to that of Figure 7, showing approximately

  How does the seal of Figure 8 or Figure 13 appear after the tubular sections of the body have been welded to each other and the weld has been ground to flush with the outer surface of the sections? ; - Figure 29 is a partial longitudinal section of a tubular element having flush surfaces ready to be welded to a complementary tubular element; FIG. 30 is a partial section, similar to that of FIG. 29, showing a tubular element having modified flush surfaces; and FIG. 31 is a partial longitudinal section, similar to that of FIG. 29, showing a tubular element having other modified flush surfaces. FIGS. 1 -A to 5 show a first embodiment of the lateral pocket mandrel according to

  the invention, indicated by the general reference numeral 20.

  The mandrel 20 comprises a body main section 20a and a body upper section 20b

  attached to each other by a circumferential weld

21.

  Threads 22 and 23 are made on the ends

  upper and lower half of the mandrel 20 to allow

  attachment to a well production column.

  The mandrel 20 shown has features

  Well-known data such as a main channel 25 with full opening through its entire length and in which well tools can pass, a pocket or a lateral belly 26 offset from the main channel 25 to define a space for maneuvering a

  decentering tool (not shown), a housing bore 27

  extending along the main bore 25 and

  singing upward in the pocket 26 to receive a flow control device (not shown), the housing bore 27 communicating at its lower end with the main bore 25 by means of a transverse channel 28 and communicating between its ends with the outside of the mandrel

by lateral openings 29.

  14. The mandrel 20 shown also comprises a well-known orientation device such as an orientation mandrel 31 having the conventional orientation slot 32 whose upper end has a stop shoulder 33 and whose lower end has a guide surface 34 for orienting a conventional orienting tool of the orienting type (not shown) which is normally actuated by organs which it carries and comes into contact with.

  with shoulder 33 facing downwards and located at the end

  upper or near the upper end of the slot 32. The orientation sleeve is traversed by a full opening channel. Therefore, the guide surface 34 is located outside the fully open bore. The mandrel also includes a deflection device such as deflectors 35 and 36 which guide flow control devices (not shown) descended into the mandrel by the well production column (not shown) on a decentering tool (not shown). ), towards the inside of the bore 27 of the housing, but which deviate from other well tools passing through the mandrel towards the main flow channel, in the well-known manner. The housing, the orientation sleeve and the

  deflectors are generally well known in the industry.

  As shown, the mandrel 20 has a substantially oval cross-section with opposite flat sides 37 and 37a which connect spaced and opposite semi-circular sides 38 and 39, as clearly shown in Fig. 2. The mandrel may however have a cross-section circular or any other shape, as desired, but the oval shape allows such mandrels to be used in double wells where these mandrels can be arranged side by side or moved so as to override each other in a casing of dimension suitable. Thus, the oval or flattened shape allows the use of a smaller diameter casing or a larger diameter column, all

otherwise things equal.

  15. The main section 20a of the body of the mandrel 20 is machined from a solid and elongated blank of a

  single piece, preferably having the desired sectional profile

  This profile is advantageously oval, as shown, although it may be circular or of any other shape. The blank of the body may be a forged, molded or other piece. The full aperture primary bore 41 is machined along the entire length of the blank, as shown, and the bore 27 of the housing is machined in the blank so as to descend along the main bore 41. bottom of the bore 27 of the housing can be reduced as indicated in 27a and as shown, or it can have the same diameter as the upper section. Lateral holes 29 are drilled in the outer surface of the blank to open into the bore of the housing, as shown in Figures 1-B and 2, to communicate the bore 27 of the housing with the outside of the housing. roughing. If the upper and lower sections of the bore 27 of the housing are of the same diameter, the bore must be slightly enlarged in the area of the lateral orifices 29 to provide a clearance for the latter so as to provide a suitable flow channel orifices 29 to the orifices of a flow control device (not shown) which can be placed in the bore of the housing to control the flow of fluids through the orifices 29 and in the transverse channel 28. It is generally desirable to to give the bore of the housing the shouldered shape shown, because such a bore is

  easier and less expensive to machine.

  An inner annular recess 44 is formed in the bore 27 of the housing, near its upper end, so as to form a shoulder 45 turned towards

  the bottom and can engage with a lock element

  carried by a flow control device (not shown).

  felt) so that the latter can be firmly anchored

in the accommodation.

  A cutter (not shown), of a diameter slightly greater than that of the main bore 41, is introduced into the lower end of the bore 41 16. to a point opposite to the lower portion of the bore 27

  housing, and is moved laterally towards this

  wise to form the transverse channel 28 and thus communicate the bore 27 of the housing and the main bore 41, as shown. It is readily apparent that the main bore 41 can communicate with the outside of the body

  through the transverse channel 28, the bore 27 of the housing

and the lateral openings 29.

  Threads 23 are machined in the lower end

  of the main bore 25 to allow a connection

  on a well production column (not shown).

  sented). The lower end of the blank of the main body advantageously has a reduced external dimension, as indicated at 47, concentrically with the threads 23, to facilitate the use of handling tools, wrenches or wrenches which can be used for fixing the mandrel on the column. At the same time that the size of the blank is reduced as indicated at 47, a guide surface 48 is preferably also formed, as shown, to guide the mandrel so that it can overcome obstacles encountered in the well during his descent. The upper end of the main section

  20a of the body is prepared to be welded to the upper section.

  20b of the body, this preparation consisting of making suitable flush surfaces on the section 20a, as shown in Figure 6. The upper end of the body section 20a is suitably erected as indicated at 51, largely chamfered on the outside as shown at 52, and slightly bored so as to have an inner annular recess 53 which includes a side surface

  lower 54 inclined inward and downward.

  The term "total opening" used herein to refer to the main channel passing through the side pocket mandrel means that this main channel is about as wide as the flow channel of the column for which the mandrel is adjusted and that it allows 17. the passage of all ordinary tools wells normally circulating in a column of this dimension. For example, in the case of a 60.33 mm nominal column, the inside diameter is 50.673 mm and the mandrel diameter is 48.285 mm, while the size of the total aperture used in industry is 47.625 mm or more, because a bore of 47.625 mm or more, provided in inboard and other fittings, allows the passage of all normal tools designed for use in such a well column. The main bores and main channels of the side pocket mandrels described herein, such as the main bore 41 machined in the main section 20a of the body, are described as having a total opening and an inside diameter greater than the minimum diameter established. for "total opening". In fact, their diameter is greater than the mandrel diameter and it allows the passage of tools whose diameter may be equal to the mandrel diameter. Such a bore may also be

qualified as non-restrictor.

  It should be noted that the aforementioned US Pat. No. 4,135,576 discloses a main body which appears to be machined in one piece and joined by circumferential welds to an upper body section. It is clearly indicated

  in the description and clearly in the figures that the

  The main body of the main body is so small (ie, much smaller in diameter than the mandrel diameter of the column bore) that additional channels of

  diversion are provided to increase the flow of

  otherwise permitted by the multiple flow control devices disposed in the multiple bores of the housing. Furthermore, it should be noted that the aforesaid Patent No. 3,040,814 describes a machined main body section which is obviously made in two halves.

  then welded to each other by structural welds.

  lengths, although this is not indicated in

the aforementioned patent.

  18. Figure 35 of the aforementioned Patent No. 3,412,806, this figure being a section along the line 35-35 of the

  Figure 12 of the same patent shows a circumferential weld-

  tial. It should be noted that, in FIG. 12, the weld is not purely circumferential, but that it comprises longitudinal sections, namely four longitudinal sections connected to each other by four curved sections.

  If the blank of a single piece of the main body

  pal, from which is made the main section of the body, is produced by molding, forging or a similar process, it is not necessary that it is full, because such a method can achieve in this draft the main bore or housing bore or both bores. If this is the case, these bores may require only minimal machining. The housing bore surely requires finishing machining and the main bore may also require finishing machining. If molding or forging is done carefully, the main bore may

  suitable for the raw state of molding or forging, without

  finishing, resulting in a reduction in the cost of machining. This saving on the cost of machining

  may be insufficient to compensate for the increase

  cost estimate for the production of molded parts

or forged more precise.

  The upper section 20b of the body is made from a certain length of tube, preferably having the same profile in cross section as that of the main section 20a of the body. The mandrels described in the present application are shown as being made in elements whose cross section is oval and comprises two opposite flat sides such as the flat sides 37 and 37a (see Figures 2 and 5). It is clear, however, that other forms are also convenient, especially forms

circular.

  - For the realization of the upper section 20b of the body, a certain length of oval tube, having the profile

  shown in FIG. 5, is heated at its upper end

  19. greater than a distance of several centimeters, and its dimension is reduced by forging or by any other suitable method, so as to form an eccentric and cylindrical end portion 61, crossed by a main channel 62 which extends along the channel the main 25 of which it is part, this channel 25 passing through the mandrel over its entire length. The reduced upper end portion 61 of the upper section 20b of the body is pushed back to a suitable outside diameter, preferably equal to the size of a column sleeve; the bore 62 is ground to a predetermined inner diameter; and the nets 22 are

  made in its upper end.

  The lower end of the upper section 20b of the body is prepared to be welded in the same manner as the upper end of the main section 20a of the body. This lower end is carefully raised as shown at 71 (see FIG. 6), chamfered widely on the outside as indicated at 72, and bored at shallow depth, so as to have an inner annular recess 73 which includes an upper side surface. 74

  tilted up and inward.

  Before welding the two sections of the body to one another, the baffles 35 and 36 are welded in place as shown. The deflector 35 is introduced into the lower end of the upper section 20b of the body

  and placed at a predetermined distance from the lower end

  of this section, in proper alignment with the

  wise of the housing, then it is welded in this position by the application of a cord 74 of non-structural weld along the two edges, as shown, or preferably the

* along the three edges. This weld has a low penetration

  and a small volume. Therefore, it does not lead to

negligible deformation.

  It should be noted that the deflector 35

  has a vertical side wall facing outwards

  and having plane 76 and curved surfaces 77 which conform to the shape of the inner wall of the mandrel at the location where this deflector is welded. Therefore, not only the deflector fits well, but its alignment with the bore of the housing, before welding, is easy to achieve. The inner wall of the deflector has a concavity 78 and has a vertical rib 79 which defines a path for guiding flow control devices to the bore 41 of the housing. The baffle is inclined downwardly and inwardly as indicated at, relative to the bore of the housing, to further facilitate guidance of the devices to the housing. In addition, the deflector 35 is inclined downwards and towards

  the interior as indicated in 81, in relation to the main channel

  25, to deflect normal well tools away from the bore 27 of the housing to the main bore 41, these normal tools generally too large diameter

  large to be able to pass between the deflectors 35 and 36.

  The other deflector 36, shown in FIG. 5, is symmetrical to the deflector 35 and is laid in the same manner and operates in exactly the same manner as the deflector 35, these two baffles cooperating with each other.

  assume the functions indicated above.

  The mandrel contains an orientation device in the form of a guide sleeve 31

  shown in particular in Figure 4. The sleeve 31 of ori-

  tation is cylindrical and has an orientation slot 32 whose upper end has a shoulder 33 facing downwards. The shoulder 33 can completely close the top

  slot 32, or it can close it only partially

  as shown. The orientation sleeve has a guide surface 34 located below the slot 32 and rising towards the lower end thereof,

as shown.

  The orientation sleeve 31 may be welded in place before or after the welding of the sections together.

  upper and main body. The sleeve 31 of orienta-

  tion is introduced into the upper end of the upper section of the body and is positioned in this section

  above the belly 26 so that its slit 32 of orienta-

  248919e 21. is facing in the opposite direction relative to the bore of the housing and that its shoulder 33, facing downward, is placed at a predetermined distance above the

  deflectors and / or housing bore.

  It is well known in the industry that the

  position and orientation of the orientation sleeves

  mainly special off-center tools used in particular side pocket mandrels and the type of selectivity used in the system. The orientation sleeve 31 disposed in the mandrel 20 can be oriented as desired and placed at the desired distance above the baffles and / or the bore of the housing, as desired, in accordance with the off centering tool to be provided. used with

the mandrel.

  To join to one another the higher sections

  the upper and the main body, their flush surfaces are brought against each other and an alignment ring or ring 84 of welding is placed so that the upper and lower sides of its outer flange 85 are in position.

  contact with the extreme faces 51 and 71 of the adjacent sections

  20a and 20b of the body. The inner side 84a of the alignment ring 84 is preferably semicircular, as shown. The ring is generally formed from a wire having the desired cross-section. This wire is then wound or curved so as to correspond to the shape of the end faces of the sections of the mandrel body, that is to say a circular, oval or other shape. A small gap (not shown) is left between the ends of the alignment ring so that the latter can be slightly compressed to be easily introduced into the shallow bore formed at the end of one of the sections of the alignment ring. body. Alignment rings are well known

manufacturers of steel parts.

  The sections of the body being assembled as shown in FIG. 6 and the main channel 25 passing through them being axially aligned, the two sections of the body, as well as the alignment ring placed between them, are welded at points spaced around their periphery and to keep them in a fixed position to allow the welding to continue. The latter is then realized in the manner well

  known, starting at the alignment ring and

  next through the mandrel, in successive passes, until the outer recess formed between the upper and lower chamfers 72 and 52 of the body sections is more than filled with filler metal. In this welding process, the alignment ring 84 is preferably melted, which ensures complete penetration of the weld and the achievement of a seal having maximum strength. The inner portion of the alignment ring 84, although fused during welding, must retain its shape to a certain extent and is an internal ridge or cord, approximately as shown in FIG. cord to remain completely in the recess defined by the inclined annular surfaces 54 and 74 so as not to protrude into the main channel 25 where it may hinder the passage or operation of well tools and

other elements.

  It should be noted that the solder 21 is pure

  circumferentially and surrounds the mandrel in a plane perpendicular to its longitudinal axis, this weld being located at the end of the main section of a single piece 20a of the body so that this main section constitutes a very effective support for the mandrel and allow the latter to withstand significant pressure differences between the inside and the outside. The web 90 remaining between the main bore 41 and the bore 27 of the housing and separating these bores reinforces the mandrel in an extremely efficient manner, particularly in the direction where this reinforcement is most necessary, that is to say in a direction perpendicular to the main axis of the oval tube and perpendicular to a plane passing through the centers of the main bore and the bore of the housing. It is obvious that this veil provides great strength to the mandrel, as described above, that this mandrel is oval, round or any other shape because, whatever the shape, the veil

  exists between the main bore and the housing bore.

  23. It is readily apparent that, since a deformation results from the withdrawal of the filler metal during cooling, the circumferential weld made at the junction of the two sections of the body produces only a slight deformation effect, since the constraints generated by this weld are distributed uniformly around the mandrel and tend to neutralize. These stresses can be eliminated by a post-heating or annealing operation, and the mandrel then only requires a slight dressing, the latter may even be unnecessary. It is evident that other types of flush surfaces may be formed on the ends of adjacent sections of the body to prepare circumferential butt welding of these sections. The embodiment shown in Figures 6 and 7 may be preferred by some manufacturers, while others prefer another form such as that shown in Figure 8. For high quality cores to be subjected to pressure and pressure. important loads, it is very desirable to obtain a complete penetration of the

welding.

  Although many forms of

  the shape shown in Figure 8 is very desirable, since it is very similar to

  the one shown in Figure 6 and it makes it possible to completely eliminate

  the alignment ring and the difficulties resulting from

  the assembly of this ring, while permitting penetration

  complete welding. However, satisfactory welds

  can be obtained with the aid of

  such as those shown in Figures 27, 29, 30

and 31.

  FIG. 8 shows that the upper section 20b 'of the body is prepared for welding in a manner very similar to that indicated for the upper section 20b shown in FIG. 6. Its lower end is erected at 71a, chamfered externally at 72a and bored on shallow depth so as to have a ring recess

  interior 73a which comprises a lateral surface 74a conver-

  giant up. The upper end of section 24.

  main body 20a 'is prepared in a very

  to that indicated for the main section 20a shown in FIG. 6, but the alignment ring is made in one piece with the body. The outer dimensions of the upper end of the main section 20a 'of the body are reduced as indicated at 95, so that this reduced portion is accommodated in the bore or shallow recess 73a of the upper section of the body, and that it also has a shoulder 96 facing upwards and abutting against the end face 71a of the upper section of the body, as shown in FIG. 8. The reduced section 95 located at the upper end of the main section 20a 'of the body adjusts relatively closely in the bore 73a of the upper section 20b 'and holds the thus-engaged ends of these two sections of the body in order to

  prevent lateral movement to facilitate the operation

  The upper end of the main body section is also widely chamfered as shown at 97. The inner edge of the upper end of the main body section 20a 'is rounded at 98 to resemble the shape. of the inner portion of the alignment ring 84 shown in Figure 6. It is desirable, but not necessary, to provide an annular recess 99 in the main body section near the rounded corner 98 to form an inner rib 100 which more perfectly gives a shape resembling that of an alignment ring made in one piece with the main section of the body. When the recess 99 is not made, the main section of the body must at least be bored a short distance to have a recess similar to the recess 53, 54 of Figure 6, this recess being intended to contain the inner part of the weld so that the latter does not clog the channel - main

passing through the mandrel 20.

  During welding, the rib 98 is melted to form part of the weld, as shown in FIG. 28, and complete penetration is achieved in the same manner that the alignment ring 84 is melted. to be part of the weld, as described with regard to

Figures 6 and 7.

  The welding is performed, as previously, by pointing at certain intervals around the mandrel, then by performing successive passes of welding around the mandrel until the recess formed by the chamfers 72a and 97 of the upper and main sections of the bodies are more than filled with filler metal. The excess filler material is then removed by grinding so as to obtain a surface that is flush with the outer surface of the mandrel body, as clearly shown on the drawing.

figure 28.

  A similar welded joint can be made by preparing the ends of the tubular elements to be connected,

  substantially as shown in Figure 27. This seal is

  The internal recesses 73a 'and 99' and the rounded rib or inner bead 98 'are substantially the same as those shown in FIG. 8, while the outer bevels 72' and 52 'are similar to the seals shown in FIGS. are substantially identical to the chamfers 72 and 52 of the

  6 and form an external circumferential cut.

  This welded joint is made as described above.

  Finally, by assembling, pointing, deposition of continuous welds to obtain total penetration, refilling of the external V-notch with successive passes of solder and, if desired, grinding of the weld so that it is flush with the surface. outer tubular elements. The welded joint completed appears substantially like

  shown in Figure 7 or Figure 28.

  Alternatively, good welds having a penetration

  total processing can be achieved by preparing the end of one of the tubular elements, for example the element 20a of Figures 6 and 7 or the element 20a 'of the

  Figure 8, as shown in Figures 29, 30 or 31.

  Such a tubular element is indicated by the letter M in FIG. 29. Its preparation consists in producing a countersink CB, then in raising the end of this element in order to form a first flat surface Pi, and to reduce the end. exterior as indicated in D for a protrusion that fits tightly but telescopically and

  easily, in the countersink of the corresponding tubular element

  The short projection P is surrounded by a second flat surface P2. The element M is chamfered widely in C, although it is advantageous that it

  be chamfered along the dotted line indicated in Ca. In a similar way, the tubular element Ma

  shown in FIG. 30 is prepared as described for FIG.

  tube M of FIG. 29, but, moreover, it is

  milled as indicated in B, this milling B eliminates

  the remaining part of the first flat surface Pi

(shown in Figure 29).

  The tubular element Mb is prepared in the same way as the element Ma of FIG. 30, but instead of being milled at B, the inside angle of the projection P (shown in FIG.

  Figure 29) is rounded to R, this rounded surface eliminates

  substantially the remaining portion of the first planar surface P1 (shown in Fig. 29). The element Mb of FIG. 31 is prepared substantially like the element 20a 'of the

  Figure 8, but it does not show the recess 99.

  One or the other of the elements Ma and Mb can be chamfered as indicated in C for the element M (FIG. 29), but the chamfer is preferably made as shown

in Ca (Figure 29).

  When the element M, Ma or Mb is coupled with a tubular element such as the element 20b of the body shown in FIGS. 6 and 7 or the element 20b 'of FIG. 8, and

  welded as described above, the penetration weld

  total implementation is similar to that shown in

section in figure 28.

  In any case, only the flush surfaces

  as shown in Figure 6 (which necessitates

  an alignment ring) or as shown in FIGS. 8, 27, 29, 30 or 31, which does not require an alignment ring, homogeneous welds, with total penetration,

  can be obtained more easily, in the absence of oxygen.

  27. Tests have shown that the two tubular elements must be: made of at least one inert gas during the weld bottom pass (s). The inert gas repels the oxygen-laden air from the bores of these assembled members and prevents the formation of scale on the inner surface of the weld, thereby allowing the molten metal to form a homogeneous, scale-free weld constituting a relatively flat and well-formed bead, substantially as shown in FIG. 7 or 28, this bead not protruding in

  the normal bore of the tubular elements.

  Although many inert gases are suitable as ambient gases in welding operations such as

  described above, argon is excellent.

  Welded joints such as those shown in Figures 6 to 8 and 27 to 31 have been made, tested,

  cut and examined and it appears that they have a

  total performance, excellent physical characteristics and

  homogeneous and substantially free of deformities

  tions. It also appears that the baffles and the orientation sleeve are internally welded to the mandrel by means of light, low volume, low penetration welds having negligible deformation effects on the mandrel, the baffles being able to be fixed in place by

brazing if desired.

  It also appears that the manufacture of the side pocket mandrel described herein does not include making plug welds or longitudinal welds that tend to weaken the mandrel, and that the only weld having an effect on the structural and physical strength and on the function of the mandrel is the circumferential weld joining the adjacent sections

  of the body, this weld being strong and well consolidated.

  In addition, it is not oriented longitudinally; its penetration

  it is total and hardly produces. deformation (because of the neutralization of the constraints

  generated by this welding) as indicated previously.

  248e196 28. The mandrel 20 with side pocket, having an orientation sleeve housed in its upper end or the same mandrel without orientation sleeve, finds its most

  great utility in well installations where provisions are

  Flow control devices, used in the boreholes of their housing, are installed and removed by means of off-centering tools lowered into the wells and removed from the wells using conventional cable. Pocket mandrels

  lateral arrangement with an orientation device placed

  below the upper end of the housing bore are generally used in subsea well installations where off-centering tools are lowered into and out of wells in the implementation of bottom pumping techniques. wells or other pumping techniques. During downhole pumping operations, tool strings are circulated in columns and flowlines by means of pumping fluid which is applied to pistons forming part of each well. Rosary of tools. Such a mandrel intended for pumped wells is represented on the

Figures 9-A and 9-B.

  FIGS. 9A and 9B thus represent a second embodiment of the invention indicated by reference numeral 120. This lateral pocket mandrel 120 is similar to the mandrel 20 in that it comprises a machined main section. 120a of body and a top section

  121b of bodies connected to each other by a circumferential weld

  ferential. The main section 120a of the body is machined from a one-piece elongated blank having the desired cross-sectional profile, as well as for the main section 20a of the body shown in Figure 1-B. A

  full aperture primary bore 141 is machined longitudinally

  nally in the blank and a housing bore 127, having a reduced lower section 127a, is machined along the main bore 141, as shown. Side ports 129 communicate the outside of the mandrel

  with the bore 127 of the housing at a point immediately

  248el96 29. above the reduced section 127a of the bore, and a

  transverse channel 128 connects the lower end of the

  wise of the housing at the main bore 141.

  A recess 144, made near the end

  upper half of the bore 127 of the housing, has a shoulder 145 facing downwards and against which can carry a locking member carried by a flow control device (not shown), so as to fix this device in the bore housing for it to act on

  the flow of fluids through the lateral orifices 129.

  The upper section 120b of the body is made substantially like the upper section 20b of the body of the lateral pocket mandrel 20 described above. It is made from a tube whose upper end is reduced to 161 and threaded at 122. It comprises, near its upper end, a stop shoulder described in more detail below. The mandrel 120 is traversed by a main channel 125 with full opening, threaded at its two ends as indicated at 122 and 123, so as to be able to

  be connected to a column of wells, this main channel

  the bore of the column when the mandrel is connected to

the latter and is part of it.

  Deflectors 135 are welded to the inner surface of the wall of the top section 120b of the body, in the appropriate position, as shown, so as to assume exactly the same function as in the form of

previous embodiment 20.

  The upper section 120b of the body is welded to the lower section 120a of the body exactly as are

  welded to each other the upper sections 20b and

  20a of the body of the mandrel 20, as previously described.

  The main section 120a of the body comprises,

  its lower end, a reduced section 147 which sensi-

  the dimension of a column sleeve and which has an internal thread 123 allowing a fixing on a

  well column. Thread 123 is made in the

  lower half of the main bore 141.

  30. An orientation device is provided in the

  main section of the body. Although this device

  may be constituted by an orientation sleeve welded or brazed in position in the main bore 141, at a point below the upper end of the bore of the housing, the lower section of the body, as represented, includes an orientation device realized

  in one piece with section 120a of the body. For constitution

  to kill the orientation device shown in Fig. 9-B, the lower end of the main bore 141 is enlarged at 141a so as to have a downwardly facing guide surface 134 having a shape similar to that of the surface 34 for guiding the orientation sleeve 31 described above. This guide surface 134 is located below the orientation slot 132 and is directed upwardly and towards the lower end of the slot. The guide surface is located outside the fully open bore. The upper end of the slot 132 opens into the main bore 141 and does not form a shoulder facing downwards, because it is not necessary to operate the pumped off-center tools used in this mandrel. However, such a shoulder can be made if desired. On the other hand, a shoulder, turned downward and intended to actuate a pumped off-center tool, is formed by a ring 191 disposed in the upper end of the mandrel 120 so as to rest on a shoulder 192, facing upwards and formed in the upper section 120b of the body, the ring being fixed in place by a weld 193, as shown, which is made by passing through the open end of the upper section of the body. The passage delimited by the ring 191 has a total opening and the shoulder 190 of this ring is located

  outside the full opening bore.

  It should be noted that patents 4,106,563

  Nos. 4,106,564 and 4,106,564 describe the orientation devices

  in a single piece forging with an upper connection forming the upper portion of the mandrel to which it is connected by a circumferential weld. The mandrel orientation device 120 according to the invention is made in one piece with the main section of the body, is arranged at the lower end of the mandrel 120 and has no stop shoulder at all. the upper end of the orientation slot. The side pocket mandrel 120 performs the same functions as the mandrel 20 described above, but it is made in a slightly different way because it is intended to be used in subsea wells and it requires the use of a pumped off center tool. This type of mandrel is very useful during pumping operations.

bottom in subsea wells.

  Rather than producing the guide surface 134 and the orientation slot 132 in one piece with the

  main section of the body, as shown, it is possible

  soldering or brazing in position in this section of the body a sleeve for orienting a decentering tool. AT

  this effect, the main bore 141 is enlarged at its end.

  lower end, as indicated in 141a, to provide sufficient space to receive a sleeve orientation similar to the sleeve 31 shown in Figure 4. It is advantageous, in this case, to mill the upper end of the counterbore 141a and chamfering appropriately, of the same

  way, the upper outer corner of the orientation sleeve

  so that a cam surface rather than a stop shoulder is formed at the upper end of the slot

  orientation. This orientation sleeve is advantageously

  appropriately sized holes made in its wall to allow the sleeve to be secured in place in

  the counterbore 141a by a non-structural plug weld.

  This weld, made with care, does not affect the passage of well tools in the orientation sleeve and does not affect

  does not deteriorate the guide surface.

  The side pocket mandrel shown on the

  FIGS. 10-A, 10-B and 11 constitute another form of embodiment

  of the invention. This mandrel, indicated by the general reference numeral 220, comprises a main body section 220a, an upper body section 220b and a section 32.

  lower 220c of bodies which are welded circumferential-

  to each other, as shown.

  The side-pocket mandrel 220 is traversed by a full-opening main channel 225, threaded at its opposite ends, as indicated at 222 and 223, so that it can be connected to a well column, the main channel 225 then extending this column when the mandrel is

  connected to it and is part of it.

  The main section 220a of the body is machined from an elongated blank in one piece, substantially

  in the same way as the main sections 20a and 120a.

  A 241 full opening main bore is machined longitudinally.

  tudinalement in the blank and a receiving bore 227

  is machined along this main bore, as shown.

  If desired, this bore may only be made

  along a portion of the blank, in which case the lower section

  This bore may have a smaller diameter,

  below the lateral openings, in which case a transverse channel

  sal such that the channel 28 of the mandrel 20 is necessary, or

  the bore 227 can be made so as to traverse completely

  the draft from one end to the other. It is advantageous for the housing bore to completely traverse the blank as shown in Figure 10-B. The lower portion of the bore 227 of the housing, as shown, is not of reduced size, as is the case of the bores 27 and 127 of the mandrels 20 and 120. The bore 227 of the housing is enlarged to 227a, from a point above the lateral orifice 229 to a point below this orifice, so that a suitable flow area is provided to allow flow in this portion free space between the lateral orifices 229 and a device for adjusting

  flow (not shown) which can be arranged in the bore of.

  housing. An inner annular recess 244 is machined in the bore 227, near its upper end, as shown, to form a downwardly facing locking shoulder 245 and against which a locking member integral with a device can be carried. flow control device (not shown) so as to fix this device in position Dt4 * 196 33. to control the flow of fluids through the lateral orifices 229 which communicate the bore of the housing with

  the outside of the mandrel. The bore 227 of the housing and the

  The main beam 241 passing through the blank communicate by their open bottom ends which are in direct communication with the space formed within the lower section 220c of the body, located immediately below. The main body section is prepared as desired at both ends to be subsequently welded to the other body sections. The upper section 220b of the body is made in the same way as the upper section 20b of the

  body of the first embodiment and it is inter-

  changeable with this section 20b, except that these two sections are welded to their respective main sections. Their structure, functions and characteristics are identical. The upper section of the body is reduced, at its upper end, as indicated at 261, above the belly 226, to the same diameter as that of a column sleeve, and this reduced section has a bore 262 in which a conventional sleeve 231 orientation is welded on

  the periphery of its upper end, as before.

  Deflectors 235 are welded to the inner wall of the upper section of the body before the latter is welded to the main body section 220a as previously described. The lower section 220c of the body of the side pocket mandrel 220 is made in the same manner as the upper section 220b of the body. It is realized in the

  same tube as the one used for the upper section.

  The lower end of the bottom section 220c of the body is reduced to 247, finished to the same diameter as a column sleeve, and internally reamed and threaded, as shown

  in 223, so that it can be connected to a column. This file

  floor is concentric to the axis of the main bore 225 which

  crosses the mandrel over the entire length.

  The upper end of the bottom section 220c of the body is prepared as desired for welding,

as previously described.

  a48> 196 34. The mandrel 220 is assembled so that the flush surfaces located at the upper and lower ends

  the lower part of the main section 220a of the body is

  nably placed in abutment with the flush surfaces located at the ends of the upper and lower sections 220b and 220c of the body. Thus assembled and their main channels 225 being axially aligned, the three adjacent sections of the body are circumferentially welded to each other as described above, so as to complete the mandrel 220. If desired, one of the end sections of the body ( upper or lower) can be assembled and welded on the main body section

  before assembly and welding of the other section.

  It has been indicated that the upper and lower sections 220b and 220c of the body are made in the same tube. To facilitate manufacture and avoid waste, these upper and lower body sections can be made in a one-piece tube by forging the reduced upper section 261 at a first end of the tubular piece and forging the reduced lower section 247. at the other end of the same tubular piece, in axial alignment with the latter. These reduced sections are then ground by dressing their ends, turning the sections reduced to the appropriate size and bore said sections to the desired inner diameter, to ensure the realization of a full size of the main channel over the entire length of the tubular part. The latter is then cut into two sections, one of which constitutes the upper section of the body and the other the lower section. In the same way, two upper sections or two lower sections can be made and then separated from each other in section. The

  simultaneous realization of two of these pieces is particularly

  conveniently and inexpensively, in cases where forging equipment can not perform the necessary forging operations on short pieces because of the length

  important that can be requested for the maintenance of the parts.

  The shorter lower section of the body may be too short to be forged with some machines, so that it is possible to save lengths of tubing by forging the sections in pairs, then

  cutting them to separate the sections from each other.

  The side pocket mandrel 220 shown in Figs. 10-A and 10-B, when supplied with or without an orientation sleeve 31, finds its greatest utility in wells where flow control devices must be introduced. in the bore 227 of the housing or removed from this bore by means of suitable decentering tools descended

  in the well and manipulated by the implementation of

conventional cables.

  The side pocket mandrel shown in Figs. 12-A and 12-B is another preferred embodiment of the invention indicated by the general reference numeral 320. This mandrel is substantially similar to the side pocket mandrel of Figs. 10-A. and 10-B except that the

  the orientation sleeve of mandrel 320 is placed in the end

  lower half of the latter and that a trigger ring

  is placed in its upper end. This mandrel is therefore intended mainly for wells such as submarine wells where flow control devices are put in place in the mandrel and removed from the latter with the aid of a decentering tool pumped into the well, this tool is part of a chain of tools moved by pumping. The side pocket mandrel 320 includes a body main section 320a which may be identical to the

  main section 220a of the mandrel 220, and a top section

  body 320b which may be identical to the section

  upper 120b of the mandrel 120, as well as a lower section

  body 320c which is very similar to the lower section

  220c, except that it additionally includes an orientation sleeve. The main section 320a of the body is made by machining an elongate blank in one piece, as well as the main section 220a described above. It has a main bore 341 with full opening and a 36.

  housing bore 327 extending along the bore 341.

  The latter is part of a main canal 325 that he

  extends and runs through the mandrel over its entire length.

  The bore 327 of the housing is widened at 327a, in the area of the lateral orifices 329 which communicate the bore 327 with the outside of the mandrel. Near its upper end, the bore 327 of the housing is widened at 344 so as to include a shoulder 345 facing downwards and against which a locking element carried by a flow control device (not shown) can be carried. in order to block this device in the bore of the housing, in a position enabling it to control the flow of fluids in the

lateral openings 329.

  The upper and lower ends of the main section 320a of the body are prepared in the desired manner so as to be welded circumferentially to the

other sections of the body.

  The upper section 320b of the body is identical to the upper section 120b of the mandrel 120 and performs exactly the same functions. It comprises, in its reduced upper end section 361, a shoulder intended to actuate a pumped decentering tool. A cylindrical ring

  391, which has a fully open bore and a shoulder

  The inner annular ring 390, facing downwards, is disposed on the top of a shoulder 392 facing upwards and formed in the reduced section 361. This ring is welded or brazed in position, as indicated by the weld 393 which is made by passing through the open end of the upper section of the body. The ring can be put in place before or after the circumferential welding of the section

  greater than the main body section.

  The lower section 320c of the body is similar to the lower section 220c of the mandrel 220, but is modified by the fact that it contains a sleeve intended for

  to orient a pumping type decentering tool, generally

  used in submarine wells or pumped wells.

  The main bore of the lower section of the body is made at a depth slightly greater than 37. That at which the main bore of the lower section 220c is formed and has a downwardly inclined shoulder 320d against which the door the chamfered upper end 320e of the orientation sleeve 331 disposed as shown in Figure 12-B. The orientation sleeve 331 is made as shown in FIG. 13. It is cylindrical in shape and has an open-ended slot 332 at both ends. It also has a guide and orientation surface 334 located below the slot 332 and directed upwards and towards this slot, in a conventional manner. The sleeve is placed in the lower section of the body, in

  a position such that it surrounds the main canal through

  the mandrel, and is welded in position as shown clearly at 333 in Fig. 14. Several holes 335 are made in the sleeve, on the opposite side to the slot

  orientation, in order to facilitate the flow between the

  wise main and the lower end of the housing bore. The lateral pocket mandrel 320 is made by circumferential welds, as well as the mandrels described above. It performs the same functions as the mandrel, these two mandrels being mainly useful in submarine wells where operations are performed at

  using well-known pumping techniques.

* In some gas lighter installations with side pocket mandrels served by pumped tools that must be moved into the well column by circulation of liquids such as water, salt water or oil , problems occur when the circulation path is bypassed by the presence of a

  or several free dwellings constituted by lateral pockets

  ral. This can occur very frequently in wells

  for example, as shown in Figure 16.

  The well installation 400 of FIG.

  equipped with casing 401 which passes through production formations

  higher and lower 402 and 403, respectively,

  communicating with bore 404 of the casing by perforations

405 and 406, respectively.

  38. A long column 411 and a short column 412

  are arranged in the casing, the long column 411

  in the vicinity of the lower zone 403 and its bore 414 communicating with this zone through the perforations 406, while the lower end of the short column 412 is disposed near the upper zone and that its bore

  415 communicates with the latter through the perforations 405.

  The upper ends of the long and short columns 411 and 412 are equipped with valves 417 and 418, respectively, connected to flow lines 419 and

420, respectively.

  A single packer or packer 422 is disposed between the upper and lower areas 402 and 403 and hermetically seals the annular space between the column 411 and the casing 401. A dual packer 423 of wells is disposed at a short distance from the above the upper zone 402 and hermetically sealing the annular space

  between the two columns 411 and 412 and the casing 401. The upper and lower zones 402 and 403 thus isolated communicate

  respectively with the short column 412 and the

  column 411, and currents from both

tions can not mix.

  The long column 411 and the short column 412 are connected by a lateral communication tube 424 so that it is possible to lower liquids in a column, to pass them in the lateral communication 424 and to bring them back into position. Another column up to the surface, in the manner of a U-shaped tube. It is obvious that during such an operation, fixed valves 425 and 426 are arranged in the long and short columns 411 and 412, respectively, below the side communication 424, to prevent the pumping of liquids to

  one or the other of formations 402 and 403.

  Long column 411 has one or more

  side-pocket mandrels, for example upper chucks

  40, 431 and 432 with lateral pocket, while the short column 412 similarly comprises upper and lower mandrels 433 and 434 to

side pocket.

  39. Through the implementation of pumping tools and techniques, flow control devices, placed in

  the mandrels 430 to 434 with side pockets can be

  screw in the classic way. However, since the position of the pumped tools depends mainly on volumetric measurements of the liquids pumped and since a free housing in a side pocket mandrel located in one or the other of the columns can allow a certain amount of pumped out of the column by the one or more lateral openings and into the annular space, or may allow the lightening gas to pass from the annular space in the column through such an orifice, the volumetric measurements of the Pumped liquids can be very imprecise. This inaccuracy may result in operations being performed at an incorrect location within the well, for example in a pocket mandrel

  other than that sought, or otherwise, and this operation

  tion can be both time consuming and expensive.

  When lightening gas such double sinks

  at least one column is equipped with lateral pocket mandrels

  Of the type described above, check valves are required to prevent backflow, i.e. the flow of liquids outward through the side ports. The check valves therefore make it possible to maintain

  in the circuit the pressure of the fluids at a value exceeding

  the pressure in the annulus and, therefore, maintain the check valves in the closed position and prevent flow through the side ports.

  The mandrels 430 to 434 with side pockets have

  each have a plurality of lateral ports 430d, 431d, 432d, 433d and 434d, respectively, and each of these orifices

  contains a check valve to prevent backflow

  or outflow through this port.

  FIG. 17 shows the lateral pocket mandrel 430 which, with the exception of the lateral orifices, is exactly identical to the side pocket mandrel 320 of FIGS.

  Figures 12-A and 12-B. However, this mandrel can be

40.

  to any one of the side pocket mandrels

shown in Figures 1-A to 15.

  The side pocket mandrel 430 of FIG. 17 has a plurality of lateral ports 430d each having a check valve as clearly shown on FIG.

  figure 18. It is easy to see that a lightening gas

  from the outside of the side pocket mandrel must pass through the side port to enter the bore 427 of the

  housing. It is preferable that the total capacity of

  lateral orifices having retaining valves equal to or greater than the flow capacity of the gas lift valve or any other flow control device disposed in the bore of the housing of the

  side pocket mandrel in accordance with the appropriate practices

requested.

  The body 430a of the mandrel 430 has a plurality of lateral channels 429 which communicate the outside of the mandrel with the bore 427 of the housing. Each channel 429 is expanded in 460, as well as in 461, as shown, so

  to receive the check valve assembly.

  The check valve assembly 462 includes a valve cage 464, a ball 465 and a seat 466 assembled as shown. FIG. 21 shows that the valve cage 464 has a flow passage 467 whose dimension is approximately equal to that of the channel 429 of the mandrel body and which is widened at 468 to form an inclined shoulder 469. The cage presents cross notches 470a and 470b that extend upward, as shown in FIG. 21, over a certain distance above shoulder 469. Thus, the notches or crossed slots delimit several fingers 471 that run downwards. and having bosses 471a projecting inwardly. The enlarged bore 468 has a diameter that is only slightly greater than the diameter of the ball, but the latter is normally in contact with the bosses 471a. and the crossed slots constitute a

  sufficient flow passage around the ball.

  The element 466 of the seat of the check valve is traversed by a channel 466a whose diameter is approximately 41. equal to that of the channel 429 of the mandrel and it comprises a seat 466d against which can bear the ball 465. The channel 466a is expanded to 466b to form an abrupt shoulder 466c. The enlarged bore 466b is sized to receive the upper end of the cage 464 which is engaged teles-

  copically in this bore as shown in Figure 19.

  The cage 464 may be attached to the seat member 466 while the ball 465 is placed therein, if desired. The parts of the check valve can be made of any suitable material. The ball is

  preferably made of stainless steel. The cage and the

  the seat may be made of steel, stainless steel or

  dable, brass or similar metal materials, but they are preferably made of plastic. Thermosetting plastics such as the material

  "RYTON" type from Phillips (polyphenylene sulphide)

  lene) or the material of the type "VESPEL SP-1" (which is a polyimide resin from the firm DuPont), for example, are very suitable for molding the cage and the seat element, in particular for the latter. . These materials are suitable for injection molding, have a suitable strength and allow to obtain a seat that corresponds to the ball to achieve a seal of good quality (there is a second

  form of polyphenylene sulphide which is a thermo-

  plastics suitable for compression molding; this material may be suitable for making the seats of the check valves such as the seat 466, but it is not suitable as well, during production, because the injection molding has advantages over the molding by

compression).

  The check valve assembly 462 (consisting of the cage 464, the ball 465 and the seat 466) is disposed in the mandrel side channel, as shown in FIG. 19, after a suitable sealing ring such as an O-ring 473 has been placed around the cage. The cage and seat of the check valve are assembled telescopically with each other and form a handy cartridge. In the case where the cage and the seat are made of material 42.

  plastic as mentioned above, it may be desirable

table to fix them together.

  The cage of the check valve assembly 462 is located in the enlarged portion 460 of the bore while the seat 466 is disposed in another enlarged portion 461 of the bore, the seal ring 473 being held between shoulder formed by the sudden change of direction between the bore 460 and the bore 461, and the end of the

  seat. The seal is also clamped between the outer surface

  the cage and the wall of bore 461, so that

  prevent any flow of fluid around the cage.

  A washer-shaped bearing member 475, traversed by a hole 475a of a size equal to that of the side channel 429, is put in place after the check valve assembly 462 as shown and supports the seat, which may be made of relatively soft non-metallic material, to hold it against the high internal pressures under which the ball 465 is applied against the

  seat with considerable force.

  A retaining ring, for example an elastic ring 476, is disposed in an annular groove 477 to retain the valve assembly in position as shown in Fig. 19. When the ball 465 rests on the seat as shown, no flow to the outside can not occur from the bore 427 of the housing to the outside of the

  chuck, because the ball closes the channel 466a of the seat. An interview

  can easily occur from outside the chuck

  to channel 427 of the dwelling, since this flow towards the

  The inner raises the ball 465 of the seat, which allows the passage of fluids through the channel 466a of the seat. Even in the case where the ball is in contact with the inner bosses 471a of the fingers 471 of the cage, the fluids can flow freely around the ball, pass through the slots 470a and 470b and return to the side channel 429, then penetrate

the bore of the housing.

  The presence of check valves in the side pocket mandrels, as previously described, allows a system such as that shown in Fig. 16 to retain 43.

  in the columns producing higher fluid pressures

  the chucks in the annular space outside the chucks, which keeps the check valves of all the chucks in the closed position and thus prevents the transfer of fluids between the column and the casing. In this way, precise volumetric measurements can be made on the liquids pumped, which allows

  to accurately determine, at any given moment, the posi-

tion of the tool-pumped string.

  It is possible to use check valves similar to the valve assembly 462 described above, but acting in the opposite direction to that indicated above. Such a check valve opposes any flow from outside

  from the side pocket mandrel to the bore of its housing.

  Fig. 22 shows a system in which such side pocket mandrels find utility. FIG. 22 represents in particular a well casing 500 which passes through three subterranean formations indicated at 501, 502 and 503, namely upper, intermediate and lower formations, respectively. These formations communicate with bore 504 of the casing through perforations 505, 506 and 507, respectively. A production column 508 is disposed in the casing 500 so that its lower end is adjacent to the lower formation 503. A first packer 509 wells obturates between the column

  and casing and separates the lower formation from the

  intermediate level. A second well packer 509a hermetically seals the annulus between the column and

  casing and separates the intermediate formation from the

tion.

  Production column 508 has a first

  mandrel 510 with a lateral pocket arranged at the level of the

  tion, and a second mandrel 511, identical to the previous one, disposed at the intermediate formation, while a fitting fitting 512 with internal reach is disposed near the lower formation. Well tools (not shown), such as injection regulators or the like, are arranged in the housing bores of the two mandrels 510 and 511, as well as in the connection 512 to

inner reach.

  Fluids injected into the well from the surface descend through the column and are injected into separate formations 501, 502 and / or 503 under the control of injection or other regulators (not shown). These fluids can be injected into the formations to maintain their pressures, as in the case of push-pull projects or recycling projects, or

  well they can be injected simply to be evacuated.

  In all cases, the pressure of formations can be considerable. When one of the injection regulators (not shown) is removed from one of the lateral pocket mandrels 510 and 511, the fluids of the corresponding formation may tend to penetrate the column and, if appropriate,

  to move from this column to one of the other formations.

  Check valves placed in the lateral orifices of

  mandrels, in the opposite direction to that indicated above.

  however, prevent such penetration of fluids. FIG. 23 shows a side-pocket mandrel including such inverted check valves, this mandrel being shown at 600. The mandrel 600 is very similar to the mandrel 20 of FIGS. 9-A and 9-B, except for its orifices. The chuck 600 may be made in the same manner as the chuck 430 of FIG. 17, if desired, or in the same manner as the chuck. any of the other mandrels described above, since it can be used with cable equipment as

  although with pumping equipment.

  FIG. 25 represents on an enlarged scale one of the check valves shown in FIG.

  view, the check valve assembly 662 is shown in positive

  preventing flow of fluids from outside the mandrel 600 to the bore 627 of its housing. The body 600a of the mandrel has a main bore 641 and a bore 45.

  627 housing. A side channel 629 communicates the frequency

  wise 627 with the outside of the mandrel.

  The side channel 629 is expanded to 630 to accommodate the check valve assembly 662, and this bore has a suitable inner annular groove 677 in

  which a retaining ring, for example an elastic ring

  676, is arranged in such a way as to maintain the whole

  check valve in position. Appropriate support,

  killed by a disc 675 in the form of a washer having a central hole 675a whose dimension is approximately equal to that of the channel 629, is disposed between the check valve and the elastic ring to form a support for the cage 664 of the check valve, this cage can be made in

plastic material.

  The assembly 662 with a check valve is very

  to the set 462 previously described. The check valve cage 664 has a bore 668 which is expanded at 669, as well as at 669a, to receive a seat member 666 and have a shoulder 669b which stops the seat member 666 in a suitable position in the seat. cage, as shown. This cage comprises fingers 670b carrying inner bosses 671a similar to those of the cage 464 of the

  check valve previously described.

  A ball 665, which can be exactly the same

  ball 465 described above, is disposed within the

  664 before the 666 seat element is

  introduced into the bore 669a of the cage and preferably

  tightly fitting in this bore. The element 666 is applied in abutment against the shoulder 669b. If desired, the seat 666 may be more firmly connected to the cage 664. This is particularly desirable if the cage and

  the seat must be made of non-metallic

  1, for example in "RYTON" or "VESPEL SP-1" molded, as mentioned previously for the assembly 462 retaining valve, in which case the seat and the cage are advantageously fixed-one to the other. In all cases, the assembly forms a device with a cartridge-like retaining valve,

which can be easily manipulated.

  46. A sealing ring, for example a seal

  663, is placed around seat 666, as shown in FIG.

  felt, to ensure the seal between this seat and the body

600a of the mandrel.

  It is evident that the check valve assembly 662 allows outward flow from the bore of the housing, but opposes any flow into the housing.

  opposite direction, that is to say towards the interior.

  It is now obvious that the restraining valve assembly 662, shown in the inverted retention position in FIG. 25, can be inverted or turned on itself with respect to the position shown in FIG. 26, in which position it is behaves like a normal check valve, similar to that shown in Figure 19, and prevents outward flow. Thus, the check valve assembly 662 can be easily moved from the position of Figure 25 to that of Figure 26, as necessary. This has the advantage of allowing the storage of mandrels having side holes lined and recessed

  as shown in FIGS. 25 and 26 and the storage of

  The chucks may then be equipped with or without check valves, and these may be placed in the normal or inverted position. In addition, mandrels used for one type of installation can be easily converted for another type of installation. In addition, replacement or

  the inversion of the check valves can be carried out easily

  readily available at the point of use, without the need to return the mandrels to the workshop or

factory.

  One or other of the check valve assemblies 462 and 662 can be easily and inexpensively produced in the form of a cartridge so as to constitute what may be called a "cartridge type check valve". . This is particularly true in the case where the cage and seat are injection molded into "RYTON" or "VESPEL SP-1", then telescopically assembled (and even attached) to each other.

  enclosing between them the stainless steel ball.

47.

  It follows from the previous description that the

  side pocket mandrel according to the invention comprises a main body section made in one piece and

  in which is machined a housing bore or side pocket

  along the main bore, and an upper body section which is connected to the upper end of the main section by a circumferential weld, the upper section of the body having a belly offset from the main channel, opening total, which crosses online

  right the mandrel, from one end to the other, and whose

  main sage of the main body section is part.

  It appears that the lower end of the main section

  blade can be made in such a way that it can be connected to

  a column of wells and may alternatively be associated with

  A lower section of the body is welded to the lower end of this main section to adapt the latter so that it can be connected to the well column. Thus, the mandrels can include two

or three body sections.

  In addition, the design of the structure of these mandrels uses only circumferential welds which

  are resistant, which can withstand different pressures

  High internal or external conditions, which can further be strengthened by the solid one-piece section of the body and having a web extending between the main bore and the housing bore. In addition, the circumferential welds used in these mandrels

  cause only slight deformations, because the contraindications

  they are distributed evenly around the mandrel so that they balance and the mandrel then requires only a little training, see no training. Circumferential welds are full penetration welds and do not reduce or affect the

  flow channel passing through the mandrel. It should also

  note that these -mandrins, while being more resilient

  tants, are also inexpensive to manufacture.

  These mandrels can be equipped with a

  orientation and / or deflection device, such as

24 8 9 1 96

  48. desired, and these devices are welded inside the mandrel without the use of plug welds requiring the realization of a hole through the wall of the mandrel for their preparation. On the other hand, the orientation device and the deflection device are welded inside the mandrel by access from the end of the body of the mandrel, a part of this welding being done before the sections of the body of the mandrel are connected. between them by circumferential welds, although a certain part of the aforementioned welding can be performed after assembly, this however not being preferred. The light welds made for the attachment of the orientation device and the deflection device are low penetration welds and they have little effect on the mandrel with respect to the deformations, the stresses

  and the operating characteristics.

  The orientation device equipping the mandrels according to the invention can be placed in the upper end or the lower end of these mandrels according to the techniques to be used for the introduction and removal of the flow control devices used. . If one has to implement cable techniques, the sleeve

  orientation is usually placed in the upper end of

  the mandrel. If pumping techniques are to be used, the orienting device is placed below the upper end of the bore of the housing. It should be noted that the main section a, 220a or 320a of the mandrel body 120, 220 or 320 with side pocket, respectively, as well as the main section

  of the body of the lateral pocket mandrel 20 can be made

  derived from a one-piece blank produced by molding, forging or a similar process. The main bore may come from molding or forging in blanks of main sections produced by such methods. The main bore may or may not require finishing machining, depending on the quality of the molding or

  forging, without departing from the scope of the invention.

248 9196

49.

  - In addition, the previous description focused on

  check valves intended to be mounted in the ori-

  or lateral channels of the side pocket mandrels described above, in order to control the flow of fluid in these lateral orifices. The check valves may be mounted to oppose any outward flow, or they may be reversed, ie turned back on themselves, to oppose any flow to the inside. Check valve assemblies may

  be easily put in place or removed at the places of use

  without the intervention of a specialist or the passage to the factory. It is therefore easy to switch them from the inward flow mode to the outward flow mode, or vice versa. The check valves can be produced easily and inexpensively in the form of cartridges by attaching the seat to the cage while the ball is held between these two parts. The seat and cage are preferably injection molded of a suitable plastics material and assembled together to form a cartridge type check valve. The reversible check valve assembly simplifies the operations of manufacturing,

storage and inventory.

  In addition, it appeared that homogeneous welds

  Full penetration, superior quality and strength, suitable for use under high pressure, can be obtained by the permanent attachment of two tubular elements using the method described above and that high quality side pocket mandrels can be obtained. be obtained using structures and processes

  manufacturing processes, as well as the welding processes described

  above. Orientation sleeves and trip rings can be welded in place as described, or brazed into place as commonly

  made in an oven, an induction oven or other such

  brazing rations being well known. It is even possible that the baffles can be fixed in place by brazing if desired. In any case, the term "welding" 50. used for such orientation sleeves, bushings

  trigger and deflectors encompasses brazing.

  It goes without saying that many modifications can be made to the mandrel described and shown without departing from the scope of the invention.

Claims (7)

  1. Method for joining two tubular elements   coaxially arranged by a circumferential weld   characterized in that it consists of drawing up the   mity of a first of the two tubular elements to form on this element an extreme flat surface, perpendicular to the longitudinal axis of the element, to check the raised surface of the first element to form an inner recess   terminating in an inclined surface spaced from said end   upright and converging towards the opposite side to this ex-   trench, to be chamfered externally the erected end of the first element, this chamfer leaving in said extreme flat surface a narrow portion which can be abutted to a corresponding flat surface of the second of the two tubular elements when these elements are assembled one to the other for welding, straightening the end of the second tubular member to form a first planar surface, reducing the outer dimension of the first planar surface to form a short projection on the end of the second tubular member and a second planar surface surrounding said projection and disposed at the first planar surface, the protrusion being dimensioned to fit relatively closely in the countersink of the first tubular member, to project the raised end of the second member to form an interior recess terminating in an inclined surface which is spaced from the erect end and converging to the side opposite to this end, outer chamfering the end of the second element to reduce the width of the second flat surface, the dimensions of this second flat surface being substantially equal to those of said flat surface remaining on the first tubular element, to assemble the two tubular elements so that their flat surfaces are arranged: fully abutting against each other, the chamfers of the   two tubular elements together forming an external cut   upper bounded by walls that converge inward on the periphery of the two elements, to point the tubular elements assembled at spaced intervals on their periphery, to weld the two tubular elements by making several circumferential welding passes from the bottom of the notch is more than filled with filler metal, the protrusion of the second tubular element being substantially melted during welding and the welding causing   no constriction of the bore of the two tubular elements.   2. The process according to claim 1, wherein   characterized in that it also consists in chamfering the edge   inside the second tubular element, and to eliminate   the remaining portion of said first flat surface, or to round off the inner edge of the second tubular member and substantially eliminate the remaining portion of said first planar surface.   - 3.- Method according to one of claims 1   and 2, characterized in that the chamfers of the two elements   tubulars are formed in such a manner that said external cut   than they delimit when the tubular elements are assembled has a profile comprising convergent side walls, connected by de-rounded roundings to a substantially flat bottom.   4. Process according to any one of the   1, 2 and 3, characterized in that it consists in   remove the excess filler metal in order to   the latter to the outer surface of the two tubular elements.   5.- Lateral pocket mandrel including several   a plurality of tubular body sections joined to each other by one or more circumferential welds   carried out by the method according to one of claims 1   and 2, characterized in that one of the tubular sections of the body is an elongated section, made in one piece, traversed by a main bore and having a bore   housing extending along said main bore.   6.- Lateral pocket mandrel comprising a plurality of tubular body sections joined to each other by one or more circumferential welds   carried out by the process according to claim 4, characterized   in that one (20a) of the tubular sections of the body is an elongate section, made in one piece and traversed by a main bore (25) and a housing bore (27) extending along the main bore (25). 7.- Lateral pocket mandrel comprising a plurality of tubular body sections joined to each other by one or more circumferential welds   carried out by the process according to claim 3,   characterized in that one (20a) of the tubular sections of the body is an elongate section, made in one piece and traversed by a main bore (25) and a housing bore (27) extending along bore principal (25).