Centraliser

Abstract

A centraliser (10) for use in centralising tubing (12) in a bore (W) comprises a first end collar (14), a second end collar (16) and a number of elongate strut members (18). The strut members (18) are interposed between the first end collar (14) and the second end collar (16) and are circumferentially arranged and spaced around the first end collar (14) and second end collar (16). The strut member (18) have a first end portion (20), a second end portion (22), an intermediate portion (24) and angled wing portions (26) which extend from the intermediate portion (24).

Claims

1. A centraliser for use in centralising tubing in a bore, comprising: a first end collar; a second end collar; and a plurality of strut members interposed between the first end collar and the second end collar, wherein at least one of the strut members comprises: a first end portion; a second end portion; an intermediate portion interposed between the first end portion and the second end portion; and one or more wing portions extending from the intermediate portion and which are angled inwards relative to the intermediate portion, wherein the first end collar, the second end collar, and the strut members are integrally formed together, and wherein the one or more wing portions are integrally formed with the intermediate portion, the one or more wing portions comprising a bent or folded portion of the intermediate portion.

2. The centraliser of claim 1, wherein the intermediate portion has a greater stiffness than the first end portion and the second end portion.

3. The centraliser of claim 1, wherein the centraliser is configurable in a first, larger diameter, configuration in which the intermediate portion assumes a radially extended position and in a second, smaller diameter, configuration in which the intermediate portion assumes a radially retracted position.

4. The centraliser of claim 3, wherein the centraliser is reconfigurable from the first, larger diameter, configuration to the second, smaller diameter, configuration.

5. The centraliser of claim 3, wherein the centraliser is reconfigurable from the second, smaller diameter, configuration to the first, larger diameter, configuration.

6. The centraliser of claim 1, wherein the end portions of the strut members are configured to permit reconfiguration between the first, larger diameter, configuration and the second, smaller diameter, configuration.

7. The centraliser of claim 6, wherein the end portions are relatively less stiff than the intermediate portion.

8. The centraliser of claim 1, wherein at least part of each wing portion is curved.

9. The centraliser of claim 8, wherein the wing portions are curved in a circumferential direction.

10. The centraliser of claim 8, wherein the wing portions are curved in an axial direction.

11. The centraliser of claim 1, wherein the strut members are bifurcated.

12. The centraliser of claim 1, wherein at least part of the intermediate portion is curved.

13. The centraliser of claim 12, wherein the intermediate portion is curved in a circumferential direction.

14. The centraliser of claim 12, wherein the intermediate portion is curved in an axial direction.

15. A method of centralising tubing in a bore using the centraliser of claim 1, comprising: providing the centraliser of claim 1; locating the centraliser on the tubing; and running the tubing and the centraliser into the bore, the centraliser being configured to engage the bore to centralise the tubing in the bore.

16. A downhole assembly comprising at least one centraliser according to claim 1.

17. The centraliser of claim 1, wherein one or more of the wing portions define a non-zero angle relative to the intermediate portion up to and including 180 degrees.

18. The centraliser of claim 17, wherein one or more of the wing portions define a non-zero angle relative to the intermediate portion up to and including 90 degrees or about 90 degrees.

19. The centraliser of claim 1, wherein one or more of the strut members comprise two wing portions.

20. The centraliser of claim 19, wherein the wing portions define different angles with respect to the intermediate portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a centraliser for centralising tubing in a wellbore;

(2) FIG. 2 shows a perspective view of the centraliser shown in FIG. 1;

(3) FIG. 3 shows an enlarged view of a strut member of the centraliser shown in FIG. 2, in isolation;

(4) FIG. 4 shows a perspective view of the intermediate portion of the strut member shown in FIG. 3, in isolation;

(5) FIG. 5 shows a plan view of the intermediate portion shown in FIG. 3;

(6) FIG. 6 shows a side view of the intermediate portion shown in FIG. 3;

(7) FIG. 7 shows cross-sectional view A-A of the intermediate portion shown in FIG. 6;

(8) FIG. 8 shows an end view of the intermediate portion shown in FIG. 3;

(9) FIG. 9 shows an alternative centraliser for centralising tubing in a wellbore;

(10) FIG. 10 shows an enlarged view of a strut member of the centraliser shown in FIG. 9, in isolation;

(11) FIG. 11 shows an alternative centraliser for centralising tubing in a wellbore;

(12) FIG. 12 shows an enlarged view of a strut member of the centraliser shown in FIG. 11, in isolation;

(13) FIG. 13 shows a diagrammatic view of a downhole assembly; and

(14) FIG. 14 shows a diagrammatic view of an alternative downhole assembly.

DETAILED DESCRIPTION OF THE DRAWINGS

(15) Referring first to FIG. 1 of the accompanying drawings, there is shown a diagrammatic view of a centraliser 10 for use in centralising tubing 12 in a bore W. As shown in FIG. 1, the tubing 12 takes the form of a casing string and the bore W takes the form of a wellbore, the annulus A between the tubing 12 and the bore W then being filled with a settable material, such as cement, which supports the tubing 12 and the bore W and provides a seal preventing uncontrolled fluid flow up the annulus A.

(16) In use, and will be described further below, the centraliser 10 is configured to engage the wall of the wellbore W to centralise the tubing 12 in the bore W.

(17) FIG. 2 of the accompanying drawings shows a perspective view of the centraliser 10 shown in FIG. 1. As shown in FIG. 2, the centraliser 10 comprises a unitary construction having a first end collar 14, a second end collar 16 and a number of elongate strut members 18. The first and second end collars 14, 16 are generally cylindrical in shape and are configured to mount the centraliser 10 onto the tubing 12. The strut members 18 are interposed between the first end collar 14 and the second end collar 16 and are circumferentially arranged and spaced around the first end collar 14 and second end collar 16. In the illustrated centraliser 10, the centraliser 10 has eight strut members 18. However, it will be recognised that the centraliser 10 may have any suitable number of strut members 18. The strut members 18 form blades of the centraliser 10.

(18) Referring now also to FIG. 3 of the accompanying drawings, which shows an enlarged view of one of the strut members 18 in isolation, it can be seen that the strut member 18 has a first end portion 20, a second end portion 22, an intermediate portion 24 and wing portions 26.

(19) As shown in FIG. 3, the first end portion 20 of the strut member 18 is bifurcated, having two connector portions 28 for connecting the first end portion 20 to the first end collar 14. An aperture 30, which in the illustrated centraliser 10 takes the form of a teardrop-shaped aperture, is defined between the connector portions 28 and the first end collar 14. The second end portion 22 of the strut member 18 is also bifurcated, having two connector portions 32 for connecting the second end portion 22 to the second end collar 16. An aperture 34, which in the illustrated centraliser 10 also takes the form of a teardrop-shaped aperture, is defined between the connector portions 32 and the second end collar 16. In the illustrated centraliser 10, the connector portions 28, 32 diverge from the intermediate portion 24 so as to be spaced apart at the first and second end collars 14, 16.

(20) In the illustrated centraliser 10, the connector portions 28, 32 each include a curved section 36, 38 proximal to the respective end collars 14, 16 and a non-curved section 40, 42, the curved sections 36, 38 by virtue of their shape having a greater stiffness than the non-curved sections 40, 42, thereby providing a transition between the end collars 14, 16 and the intermediate portion 24.

(21) FIGS. 4 to 8 of the accompanying drawings shows the intermediate portion 24 of one of the strut members 18 of the centraliser 10.

(22) As shown, the intermediate portion 24 is curved in both circumferential and axial directions and defines a convex curved outer surface. The curved shaped of the intermediate portion 24 provides for greater stiffness than the end portions 20, 22.

(23) The wing portions 26 extend from the intermediate portion 24 and are angled relative to the intermediate portion 24. In the illustrated centraliser 10, the wing portions 26 define an angle of approximately 90 degrees to the intermediate portion 24. However, the wing portions 26 may define other angles with respect to the intermediate portion 24.

(24) As shown in FIG. 6, for example, the wing portions 24 are also curved in an axial direction.

(25) The wing portions 26 have been found to further enhance the stiffness of the intermediate portion 24 relative to the end portions 20, 22. Moreover, the provision of the wing portions 26 which are angled relative to the intermediate portion 24 offsets the intermediate portion 24 from the tubing 12 in use.

(26) Beneficially, the provision of a centraliser 10 having one or more strut members 18 with an intermediate portion 24 having a greater stiffness than the end portions of the strut member provides for preferential flexing of the strut member at the end portions rather than the intermediate portion. The preferential flexing of the strut members 18 at the intermediate portion provides a centraliser 10 having sufficient rigidity to maintain the tubing 12 in a generally central position in the bore W while also having sufficient flexibility to pass through wellbore restrictions and recover to the required shape. The provision of wing portions 26 has been found to further enhance the stiffness of the intermediate portion 24 relative to the end portions 20, 22. Moreover, the provision of the wing portions 28 which are angled relative to the intermediate portion 24 offsets the intermediate portion 24 from the tubing 12 in use.

(27) It will be recognised that various modifications may be made without departing from the scope of the invention as defined in the claims.

(28) For example, FIG. 9 of the accompanying drawings shows an alternative centraliser 110 for centralising the tubing 12 in the bore W.

(29) As shown in FIG. 9, the centraliser 110 comprises a unitary construction having a first end collar 114, a second end collar 116 and a number of elongate strut members 118. The first and second end collars 114, 116 are generally cylindrical in shape and are configured to mount the centraliser 110 onto the tubing 12. The strut members 118 are interposed between the first end collar 114 and the second end collar 116 and are circumferentially arranged and spaced around the first end collar 114 and second end collar 116. In the illustrated centraliser 110, the centraliser 110 has eight strut members 118. However, it will be recognised that the centraliser 110 may have any suitable number of strut members 118. The strut members 118 form blades of the centraliser 110.

(30) Referring now also to FIG. 10 of the accompanying drawings, which shows an enlarged view of one of the strut members 118 in isolation, it can be seen that the strut member 118 has a first end portion 120, a second end portion 122, an intermediate portion 124 and wing portions 126.

(31) As shown in FIG. 10, unlike the strut member 18 described above, the first end portion 120 of the strut member 118 is not bifurcated, having a single connector portion 128 for connecting the first end portion 120 to the first end collar 114 and a connector portion 132 for connecting the second end portion 122 to the second end collar 116. In the illustrated centraliser 110, the end portions define a convex outer surface.

(32) In the illustrated centraliser 110, the connector portions 128, 132 each include a curved section 136, 138 proximal to the respective end collars 114, 116 and a non-curved section 140, 142, the curved sections 136,138 by virtue of their shape having a greater stiffness than the non-curved sections 140,142, thereby providing a transition between the end collars 114, 116 and the intermediate portion 124.

(33) As shown in FIGS. 9 and 10, the intermediate portion 124 is curved in both circumferential and axial directions and defines a convex curved outer surface. The curved shaped of the intermediate portion 124 provides for greater stiffness than the end portions 120,122.

(34) The wing portions 126 extend from the intermediate portion 124 and are angled relative to the intermediate portion 124. In the illustrated centraliser 110, the wing portions 126 define an angle of approximately 90 degrees to the intermediate portion 124. However, the wing portions 126 may define other angles with respect to the intermediate portion 124.

(35) As shown in FIG. 10, for example, the wing portions 124 are also curved in an axial direction.

(36) As described above, the wing portions 126 have been found to further enhance the stiffness of the intermediate portion 124 relative to the end portions 120, 122. Moreover, the provision of the wing portions 126 which are angled relative to the intermediate portion 124 offsets the intermediate portion 124 from the tubing 12 in use.

(37) FIG. 9 of the accompanying drawings shows an alternative centraliser 110 for centralising the tubing 12 in the bore W. Like components between the centralisers 10, 110 are represented by like reference signs incremented by 100.

(38) As shown in FIG. 9, the centraliser 110 comprises a unitary construction having a first end collar 114, a second end collar 116 and a number of elongate strut members 118. The first and second end collars 114, 116 are generally cylindrical in shape and are configured to mount the centraliser 110 onto the tubing 12. The strut members 118 are interposed between the first end collar 114 and the second end collar 116 and are circumferentially arranged and spaced around the first end collar 114 and second end collar 116. In the illustrated centraliser 110, the centraliser 110 has eight strut members 118. However, it will be recognised that the centraliser 110 may have any suitable number of strut members 118. The strut members 118 form blades of the centraliser 110.

(39) Referring now also to FIG. 10 of the accompanying drawings, which shows an enlarged view of one of the strut members 118 in isolation, it can be seen that the strut member 118 has a first end portion 120, a second end portion 122, an intermediate portion 124 and wing portions 126.

(40) As shown in FIG. 10, unlike the strut member 18 described above, the first end portion 20 has a single connector portion 128 for connecting the first end portion 120 to the first end collar 114 and a connector portion 132 for connecting the second end portion 122 to the second end collar 116. In the illustrated centraliser 110, the connector portions 128, 132 each include a curved section 136, 138 proximal to the respective end collars 114, 116 and a non-curved section 140, 142, the curved sections 136, 138 by virtue of their shape having a greater stiffness than the non-curved sections 140, 142, thereby providing a transition between the end collars 114, 116 and the intermediate portion 124.

(41) As shown in FIGS. 9 and 10, the intermediate portion 124 is curved in both circumferential and axial directions and defines a convex curved outer surface. The curved shaped of the intermediate portion 124 provides for greater stiffness than the end portions 120,122.

(42) The wing portions 126 extend from the intermediate portion 124 and are angled relative to the intermediate portion 124. In the illustrated centraliser 110, the wing portions 126 define an angle of approximately 90 degrees to the intermediate portion 124. However, the wing portions 126 may define other angles with respect to the intermediate portion 124.

(43) As shown in FIG. 10, for example, the wing portions 124 are also curved in an axial direction.

(44) In use, the centraliser 110 may be configured for location on the tubing 12, the centraliser 110 configured to engage the wall of the bore W to centralise the tubing 12 in the bore W. The provision of a centraliser 110 having one or more strut members 118 with an intermediate portion 124 having a greater stiffness than the end portions 120,122 of the strut member 118 provides for preferential flexing of the strut member 118 at the end portions 120,122 rather than the intermediate portion 124. The preferential flexing of the strut member 118 at the intermediate portion provides a centraliser 110 having sufficient rigidity to maintain the tubing 12 in a generally central position in the bore W while also having sufficient flexibility to pass through wellbore restrictions and recover to the required shape. The provision of wing portions 126 has been found to further enhance the stiffness of the intermediate portion relative to the end portions 120, 122. Moreover, the provision of the wing portions 126 which are angled relative to the intermediate portion 124 offsets the intermediate portion 124 from the tubing 12 in use.

(45) FIG. 11 of the accompanying drawings shows another alternative centraliser 210 for centralising the tubing 12 in the bore W. Like components between the centralisers 10, 210 are represented by like reference signs incremented by 200.

(46) As shown in FIG. 11, the centraliser 210 comprises a unitary construction having a first end collar 214, a second end collar 216 and a number of elongate strut members 218. The first and second end collars 214, 216 are generally cylindrical in shape and are configured to mount the centraliser 210 onto the tubing 12. The strut members 218 are interposed between the first end collar 214 and the second end collar 216 and are circumferentially arranged and spaced around the first end collar 214 and second end collar 216. In the illustrated centraliser 210, the centraliser 210 has eight strut members 218. However, it will be recognised that the centraliser 210 may have any suitable number of strut members 218. The strut members 218 form blades of the centraliser 210.

(47) Referring now also to FIG. 12 of the accompanying drawings, which shows an enlarged view of one of the strut members 218 in isolation, it can be seen that the strut member 218 has a first end portion 220, a second end portion 222, an intermediate portion 224 and wing portions 226.

(48) As shown in FIG. 12, like the centraliser 110, the first end portion 220 has a single connector portion 228 for connecting the first end portion 220 to the first end collar 214 and a connector portion 232 for connecting the second end portion 222 to the second end collar 216. In the illustrated centraliser 210, the end portions define a concave outer surface.

(49) In the illustrated centraliser 210, the connector portions 228, 232 each include a curved section 236, 238 proximal to the respective end collars 214, 216 and a non-curved section 240, 242, the curved sections 236, 238 by virtue of their shape having a greater stiffness than the non-curved sections 240, 242, thereby providing a transition between the end collars 214, 216 and the intermediate portion 224.

(50) As shown in FIGS. 11 and 12, the intermediate portion 224 is curved in both circumferential and axial directions and defines a convex curved outer surface. The curved shaped of the intermediate portion 224 provides for greater stiffness than the end portions 220, 222.

(51) The wing portions 226 extend from the intermediate portion 224 and are angled relative to the intermediate portion 224. In the illustrated centraliser 210, the wing portions 226 define an angle of approximately 90 degrees to the intermediate portion 224. However, the wing portions 226 may define other angles with respect to the intermediate portion 224.

(52) As shown in FIG. 12, for example, the wing portions 224 are also curved in an axial direction.

(53) In use, the centraliser 210 may be configured for location on the tubing 12, the centraliser 210 configured to engage the wall of the bore W to centralise the tubing 12 in the bore W. The provision of a centraliser 210 having one or more strut members 218 with an intermediate portion 224 having a greater stiffness than the end portions 220, 222 of the strut member 218 provides for preferential flexing of the strut member 218 at the end portions 220, 222 rather than the intermediate portion 224. The preferential flexing of the strut member 218 at the intermediate portion provides a centraliser 210 having sufficient rigidity to maintain the tubing 12 in a generally central position in the bore W while also having sufficient flexibility to pass through wellbore restrictions and recover to the required shape. The provision of wing portions 226 has been found to further enhance the stiffness of the intermediate portion relative to the end portions 220, 222. Moreover, the provision of the wing portions 226 which are angled relative to the intermediate portion 224 offsets the intermediate portion 224 from the tubing 12 in use

(54) Referring now to FIG. 13 of the accompanying drawings, there is shown a downhole assembly 1000 comprising a plurality of centralisers 1010. In the illustrated assembly 1000, the centralisers 1010 are identical to the centraliser 10 shown in FIG. 1. However, it will be understood that one or more of the centralisers 1010 may be identical to the centraliser 110 or centraliser 210 described above.

(55) As shown in FIG. 13, the centralisers 1010 are disposed on tubing 1012 which takes the form of a bore-lining tubing string, and more particularly a casing string, the tubing 1012 configured to be run into a bore W′ in the form of a wellbore. In use, the centralisers 1010 centralise the tubing 1012 in the bore W′ as described above.

(56) An alternative downhole assembly 2000 is shown in FIG. 14 of the accompanying drawings. In the illustrated assembly 2000, the centralisers 2010 are identical to the centraliser 10 shown in FIG. 1. However, it will be understood that one or more of the centralisers 2010 may be identical to the centraliser 110 or centraliser 210 described above.

(57) As shown in FIG. 14, the centralisers 2010 are disposed on tubing 2012 which takes the form of a tubing string, and more particularly a work string, the tubing 2012 configured to be run into a bore W″ in the form of a cased bore. In use, the centralisers 2010 centralise the tubing 1012 in the bore W″ as described above.