Device arranged for attaching a pipe stem on a tubular body

Abstract

An attachment device for an element is made to be arranged on a downhole tubular body, in which an end portion of a sleeve, which is arranged to surround a portion of the tubular body, comprises an attachment portion. The attachment portion comprises at least one clamping element arranged for axial displacement by the abutment of an abutment surface against a conical abutment portion of a surrounding adapter sleeve.

Claims

1. A device for attachment to a tubular body comprising: a first sleeve including an end portion, the sleeve configured to surround the tubular body, the end portion comprising a plurality of axial extensions separated by a plurality of slits, the extensions including a locking portion and a gripping portion; and a second sleeve configured to encircle the end portion of the first sleeve, the second sleeve including a conical abutment portion and a corresponding locking portion configured to engage with the locking portion of the first sleeve; wherein the gripping portion of the extensions comprises a radially inward facing clamping surface including radially inwardly gripping projections, as well as a radially outward facing abutment surface opposite the clamping surface the extensions further comprise a radially outward facing abutment surface, the locking portion of the first sleeve comprises a plurality of circumferential annular catches located on the external surface of the first sleeve; and the locking portion of the second sleeve comprises a plurality of complimentary circumferential annular catches located on the internal surface of the second sleeve; and wherein the end portion of the first sleeve and the second sleeve are configured such that when the end portion of the first sleeve is axially brought together with the second sleeve so that the locking portion of the extensions of the first sleeve are engaged with the locking portion of the second sleeve, the conical abutment portion of the second sleeve displaces the abutment surface of the gripping surface.

2. The device of claim 1, wherein the radially inward gripping projections comprise circumferential teeth.

3. The device of claim 2, wherein the radially inward gripping projections comprise a plurality of axially spaced circumferential teeth.

4. The device of claim 2, wherein the locking portion of the axial extensions of the first sleeve further comprises a recess located on the radially inward facing surface, opposite the plurality of catches.

5. The device of claim 4, wherein as the end portion of the first sleeve is axially brought together with the second sleeve so that the locking portion of the extensions of the first sleeve are engaged with the locking portion of the second sleeve, the recess allows the locking portion of the extensions to deflect axially inward.

6. The device of claim 1, wherein the circumferential annular catches located on the first sleeve comprise a sloped first side face facing the distal end of the axial extensions, and an opposite second side face forming an abutment surface approximately perpendicular to a center axis of the first sleeve.

7. The device of claim 6, wherein the sloped first side face has a pitch of about 20 to about 35 degrees.

8. The device of claim 7, where the sloped first side face has a pitch of about 30 degrees.

9. The device of claim 1, wherein the slits are straight and parallel with one another.

10. The device of claim 1, wherein the radially outward facing abutment surface of the extensions is located on the distal end of the extensions.

11. The device of claim 10, wherein the radially outward facing abutment surface is conical.

12. The device of claim 1, wherein the locking portion of the first sleeve is engaged with the locking portion of the second sleeve by a ratchet engagement.

13. An attachment assembly for a tubular body comprising: a sleeve having a tubular attachment portion, the attachment portion comprising a plurality of clamping elements extending in an axial direction towards a distal end of the attachment portion and arranged for radial displacement toward an encircled tubular body, the clamping elements formed by parallel, axial slits, the plurality of clamping elements comprising a gripping face on an inner surface of the clamping elements, the gripping face comprising teeth, the plurality of clamping elements further comprising at least one circumferential annular catch on an outer surface of the clamping element, the circumferential annular catch comprising a sloped first side face facing the distal end of the clamping element and an opposite second side face forming an abutment surface approximately perpendicular to a center axis of the sleeve; and an adapter sleeve arranged to inwardly, radially displace the clamping elements, the adapter sleeve comprising an engagement element projecting inwards having a complementary cross section to a cross section of the circumferential annular catch, wherein the attachment assembly is arranged such that when the adapter sleeve is moved in over the attachment portion, the adapter sleeve displaces the clamping elements inwards and the engagement element slides over the sloped first side face until the engagement element engages behind the catch by axially supporting abutment against the abutment surface of the catch.

14. The assembly of claim 13, wherein the teeth extend circumferentially around an inner surface of the clamping elements.

15. The assembly of claim 14, wherein the sloped first side face has a pitch of about 20 to about 35 degrees.

16. The assembly of claim 14, wherein the tubular attachment portion further comprises a plurality of circumferential annular catches spaced apart axially.

17. The assembly of claim 16, where wherein the adapter sleeve comprises a plurality of engagement elements spaced apart axially and wherein an axial spacing of the circumferential annular catches corresponds to axial spacing of the engagement elements.

18. The assembly of claim 13, wherein the slits are straight and parallel with one another.

19. The assembly of claim 13, wherein the adapter sleeve comprises a conical abutment portion having a decreasing diameter away from the engagement elements.

20. The assembly of claim 13, further including a centralizer attached to the sleeve having a tubular attachment portion, the centralizer axially attached to the end of the sleeve opposite the attachment portion of the sleeve.

21. The device of claim 13, wherein the engagement element engages the catch by a ratchet engagement.

22. An assembly for tubular body comprising: a centralizer deployed on the tubular body; and an attachment device deployed and fixed on the tubular body, the attachment device adjacent to the centralizer, the attachment device comprising; a sleeve having a tubular attachment portion, the attachment portion comprising a plurality of clamping elements extending in an axial direction towards a distal end of the attachment portion and encircling tubular body, the clamping elements formed by slits penetrating the attachment portion, the plurality of clamping elements comprising a gripping face on an inner surface of the clamping elements, the gripping face comprising a plurality of axially spaced circumferential teeth at least partially embedded into the surface of the tubular body, the plurality of clamping elements further comprising at least one circumferential annular catch on an outer surface of the clamping element, the circumferential annular catch comprising a sloped first side face facing the distal end of the clamping element and an opposite second side face forming an abutment surface approximately perpendicular to a center axis of the sleeve; and an adapter sleeve that encircles and engages with the tubular attachment portion, providing inward radial force upon the clamping elements, the adapter sleeve comprising an engagement element projecting inwards having a complementary cross section to a cross section of the circumferential annular catch.

23. The assembly of claim 22, wherein the centralizer comprises an elongated mandrel configured to surround a portion of the tubular body, the mandrel including a plurality of stabilizing ribs projecting from the outer surface of the mandrel.

24. The assembly of claim 22, wherein the attachment device is integrally attached to centralizer.

25. The assembly of claim 22, wherein the attachment device prevents the centralizer from moving in the axial direction along the tubular body.

26. The assembly of claim 22, wherein the tubular body is a casing, a liner or a bottom-hole assembly.

27. The assembly of claim 22, wherein the slits of the attachment portion further separate the circumferential annular catches of the respective clamping elements, defining the circumferential extent of the circumferential annular catches.

28. The device of claim 22, wherein the engagement element engages the circumferential annular catch by a ratchet engagement.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In what follows, an example of a preferred embodiment is described, which is visualized in the accompanying drawings, in which:

(2) FIG. 1 shows a mandrel axially fixed with two sleeves according to the invention, the sleeves having been pulled slightly away from the end faces of the mandrel for the sake of exposure, and the mandrel being provided with stabilizers attached to an external jacket surface;

(3) FIG. 2 shows, in perspective, two sleeves according to the invention integrated in the mandrel;

(4) FIG. 3 shows, on a larger scale, an axial section through an attachment portion with an adapter sleeve formed as a nut screwed partially onto the attachment portion;

(5) FIG. 4a shows, on a larger scale, an axial section through an alternative embodiment of the attachment portion;

(6) FIG. 4b shows a radial section IV-IV according to FIG. 4a;

(7) FIG. 5 shows, on a larger scale, an axial section of a section of an alternative embodiment of the attachment portion and the nut, a locking portion in an end portion of the nut being engaged in a latch groove in the mandrel;

(8) FIG. 6 shows an axial section through an attachment portion and an adapter sleeve provided with a catch system, in which engagement elements projecting inwards on the adapter sleeve are being moved into engagement with corresponding catches on the attachment portions;

(9) FIG. 6a shows an enlarged section of the catch system; and

(10) FIG. 7 shows a view corresponding to FIG. 6, but where the engagement elements are fully engaged in the catches.

DETAILED DESCRIPTION OF THE DRAWINGS

(11) In the figures, the reference numeral 1 indicates a sleeve in the form of an elongated mandrel provided with several function elements 2, shown in FIGS. 1 and 2 as ribshaped stabilizing elements projecting from a jacket surface 12 of the mandrel 1. The mandrel 1 is arranged to releasably surround a portion of a tubular body 3, shown schematically in FIGS. 1 and 2 as a casing. In FIG. 1, the mandrel 1 is fixed by means of two separate sleeves 1a, for example when it is desirable that the mandrel 1 with the function elements 2 should be rotatable on the tubular body 3, as an attachment sleeve 1a is positioned in an axially supporting manner against both end portions 11 of the mandrel 1, which, in this embodiment, have straight end faces 111. The sleeves 1a are attached in a rotationally rigid manner to the tubular body 3 so that the mandrel 1 may rotate freely. In FIG. 2, attachment devices for the sleeves 1a are integrated in both end portions 11 of the mandrel 1 so that the mandrel 1 is attached to the tubular body 3 in a rotationally rigid manner.

(12) In the following description, the attachment device is described in relation to the sleeve 1a, but is valid also when the sleeve 1a forms an elongated mandrel 1 provided with said attachment device(s).

(13) An end portion 11 of the sleeve 1a is provided with an attachment portion 13 which, in a first embodiment (see FIG. 3) includes a clamping portion 131 arranged to abut in a holding manner against the tubular body 3. The clamping portion 131 is formed from several lip-shaped clamping elements 1312 projecting in the axial direction from the sleeve 1a, the clamping elements 1312 being separated by slits 1311. The slits 1311 are shown here as straight-lined and parallel and are arranged in the axial direction of the sleeve 1a, but other designs are possible as well. The internal side faces of the to clamping elements 1312 form clamping faces 1313 arranged to rest, in an active position, against the tubular body 3. The clamping faces 1313 are gently conical with an increasing diameter towards the free ends of the clamping elements 13, typically with a pitch angle in the range of 2-5. The pitch angle roughly corresponds to the pitch angle of the abutment surface 142 of an encircling adapter sleeve 14 (see below) to provide the desired contact between the clamping faces 1313 and the surrounded tubular body 3. In one embodiment (see FIGS. 6 and 7), a portion of the clamping faces 1313 constitutes a gripping face 1313, shown as toothed here, but other friction-enhancing designs may be used, for example serration.

(14) In a second embodiment (see FIGS. 4a and 4b), the attachment portion 13 is provided with several recesses 132, each accommodating a clamping element 1312 in the form of a curved clamping piece provided with a conical, outward, abutment surface 1315 and a cylindrical, inward, clamping face 1313. The clamping face 1313 is preferably rough, for example serrated, to exhibit sufficiently large friction against a surface. The recess 132 is provided with ledges 1321 arranged to receive corresponding collar portions 1314 having the effect of preventing the clamping element 1312 from falling out of the recess 132.

(15) In one embodiment, a locking portion 133 is arranged to engage in the adapter sleeve 14 in an axially fixing manner as the locking portion 133 is formed as an externally threaded portion extending along a portion of the jacket surface 12 from the bottom of the slits 1311.

(16) In this embodiment, the adapter sleeve 14 is formed as a nut provided with an internally threaded portion 141 complementary to the externally threaded portion 133 of the sleeve 1a. In the further description, the term nut is partly used when the adapter sleeve 14 is provided with an internally threaded portion 141.

(17) In another embodiment, the axial fixing of the adapter sleeve 14 on the attachment portion 13 is provided by a catch system, the locking portion 133 including several external catches 134, each extending in the circumferential direction of the jacket surface 12 across a region of the attachment portion 13 which is split by slits, shown in FIGS. 6 and 7 as the slits 1311 defining the clamping elements 1312. Internally to the locking portion 133, the attachment portion 13 exhibits a recess 135 which, with its diameter larger than that of the adjacent portions of the centre bore of the sleeve 1a, extends beyond the axial extent of the locking portion 133. The slitting of the attachment portion 13 together with the corresponding internal recess 135 allows the locking portion 133 to be pressed inwards when the adapter sleeve 14 (see FIG. 7), which, in this embodiment, is provided with engagement elements 141 projecting inwards, is moved in over the locking portion 133. In the embodiment shown, the catches 134 are provided with a first, conical side face 134a facing the end of the clamping portion 131, for example with a pitch in the range of 20-35, about 30 shown here. An opposite, second side face 134b forms an abutment surface, shown here as a shoulder standing perpendicularly to the centre axis of the clamping portion 131. Correspondingly, the engagement elements 141 of the adapter sleeve 14 have a cross section complementary to the cross section of the catches 134 so that an engagement element 141 will slide with a conical, inward side face 141a on the conical outward side face 134a of the catch 134 as the locking portion 133 is compressed in the radial direction until the engagement element 141 engages behind said catch 134 by its axially supporting abutment against the abutment surface 134b of the catch 134. In this embodiment, the engagement elements 141 are typically similarly shaped and arranged with regular axial spacing. Here, the locking portion is shown with several catches 134 spaced apart axially, the axial spacing pitch corresponding to the spacing of the engagement elements 141 of the adapter sleeve 14.

(18) Reference is now made to FIGS. 3 and 4a in particular. Between the engagement elements 141 and a first end 14a of the adapter sleeve 14, a conical abutment portion 142 extends with a diameter decreasing in the direction away from the engagement elements 141. The pitch angle of the conical abutment portion 142 is preferably equal to the pitch angle of the clamping faces 1313 of the clamping element 1312 or the abutment surface 1315 of the clamping elements 1312, in order thereby to provide good contact between the clamping faces 1313 of the lips 1312 or clamping pieces 1312 and the surrounded tubular body 3 when the clamping elements 1312, 1312 are in their active positions.

(19) In the embodiment as a nut, the adapter sleeve 14 is provided with several grip portions 144 (se FIGS. 3 and 4a), shown here as cut-outs extending through the conical portion of wall of the adapter sleeve 14. The grip portions 144 are arranged to be releasably engaged by a tool (not shown) for rotating the nut 14.

(20) Reference is now made to FIG. 5, in which an embodiment with several parallel latch grooves 134 arranged adjacent to the externally threaded portion 133 is shown. A complementary engagement element 141 projects inwards like a ridge from the internal wall surface of the nut 14, with a distance to the internally threaded portion 141. The engagement element 141 is arranged to be yielding so that by the axial displacement of the nut 14 on the externally threaded portion 133, it may climb on the side edges of the latch grooves 134. The engagement portion 141 may, for example, be formed as a yielding one by the use of a small material thickness in the adjacent portion of the wall of the nut 14, possibly by the engagement portion 141 and the adjacent portion of the wall of the nut 14 being split with slits arranged axially (not shown).

(21) Alternatively, the nut 14 may be provided with a catch system, as described above and shown in the FIGS. 6 and 7, to prevent the nut 14 from unscrewing.

(22) It is obvious to provide both end portions 11 of a sleeve 1a formed as a mandrel 1a with attachment portions 13 of the kind as described above. It is also obvious to choose a thread direction that will prevent the nut 14 from unscrewing as the tubular body 3 is rotated in its normal direction of rotation.

(23) When a pipe string that is being constructed from said tubular bodies 3 is to be provided with function elements 2, for example a new casing is to be centred in a previously installed casing in such a way that sufficient clearance is ensured between the casings for the satisfactory introduction of cement, a mandrel 1 with function elements 2 and adapter sleeve/sleeves 14 is slipped over the relevant tubular body 3 and fixed in the desired position by the adapter sleeve/sleeves 14 being clamped in such a way that the clamping faces 1313 and possible gripping faces 1313 of the clamping elements 1312 are pressed against the jacket surface of the tubular body 3. By the use of attachment sleeves 1a according to the invention, the mandrel 1, attachment sleeve/sleeves 1a and adapter sleeve/sleeves 14 are slipped over the tubular body 3 in the desired order and orientation. The attachment sleeve/sleeves 1a is/are attached in a manner corresponding to that described above. Correspondingly, the sleeve 1a is used as an attachment for one or more function elements 2 by the function element 2 being attached to a suitable anchoring point 136 on the sleeve, shown in FIG. 6 as a threaded recess, and shown in FIG. 7 as a projecting threaded pin.