Seal assembly

Abstract

A seal assembly for establishing a seal in an annulus between a mandrel and a bore wall includes a mandrel, a radially expandable seal element mounted on the mandrel, and a setting arrangement mounted on the mandrel and being arranged to displace the seal element radially outwardly from a retracted configuration to an extended configuration. The expandable seal element defines a cup seal when in the extended configuration.

Claims

1. A seal assembly for establishing a seal in an annulus between a mandrel and a bore wall, comprising: a radially expandable seal element; and a setting arrangement for displacing the seal element radially outwardly from a retracted configuration to an extended configuration, wherein the setting arrangement comprises a deflector operable to displace the seal element radially outwardly and an intermediate member interposed between the seal element and the deflector, the seal element, the intermediate member and the deflector being axially slidable relative to each other and the mandrel to position the deflector and the intermediate member between the seal element and the mandrel in a radially stacked configuration to affect the radial expansion of the seal element, wherein the expandable seal element defines a cup seal when in the extended configuration, wherein the seal element comprising a fixed end region which is radially fixed, and an opposite free end region which is configured to be radially expanded by the setting arrangement.

2. The seal assembly according to claim 1, wherein the setting arrangement supports the seal element when in the extended configuration.

3. The seal assembly according to claim 1, wherein the free end of the seal element defines a ramp surface to facilitate inter-engagement with the setting arrangement and permit radial expansion of the seal element, and to provide relief between the seal element and the setting arrangement when the seal element is in the extended configuration to permit the seal element to define and function appropriately as a cup seal.

4. The seal assembly according to claim 1, wherein at least one of: the seal element is generally cylindrical when in the retracted configuration; and the setting arrangement is operable to deform the seal element to define a general cup-shape when in the extended configuration.

5. The seal assembly according to claim 1, wherein the seal element and the setting arrangement are axially arranged relative to each other in end-to-end relationship when the seal element is in the retracted configuration.

6. The seal assembly according to claim 1, wherein the deflector defines an annular component.

7. The seal assembly according to claim 1, wherein one of: the setting arrangement further comprises an actuator operable to provide relative movement between the seal element and the deflector; and the setting arrangement further comprises an actuator operable to provide relative movement between the seal element and the deflector, the actuator comprising a ram arrangement.

8. The seal assembly according to claim 1, wherein at least one of: the intermediate member defines a first ramp surface for engaging the seal element to permit said seal element to be radially expanded, and a second ramp surface for engaging the deflector to permit said intermediate member to be radially expanded by the deflector; the intermediate member comprises a metal insert; the setting arrangement comprises a plurality of intermediate members; the setting arrangement comprises a plurality of intermediate members-, at least one of the intermediate members is different from at least other of the intermediate members; and the setting arrangement comprises a plurality of intermediate members, at least one of the intermediate members comprises a material of different hardness.

9. The seal assembly according to claim 1, comprising a seal support arrangement for providing axial support to the seal element at least when said seal element is in the extended configuration.

10. The seal assembly according to claim 9, wherein at least one of: the seal support arrangement is reconfigurable between a retracted configuration and an extended configuration; the seal support arrangement is reconfigurable between a retracted configuration and an extended configuration, wherein the seal support arrangement is configured in the extended configuration simultaneously with extension of the seal element; the seal support arrangement is activated to extend during the same activation event as the seal element; the seal support arrangement is activated to extend by inter-engagement with the seal element, such that the seal support arrangement will be extended as the seal element is extended; and the seal support arrangement is configured to be extended by the setting arrangement.

11. The seal assembly according to claim 9, wherein the seal support arrangement comprises multiple support elements each being radially extendable to provide support to the seal element.

12. The seal assembly according to claim 11, wherein the seal support arrangement comprises a seal support deflector for displacing the support elements radially outwardly.

13. The seal assembly according to claim 12, wherein at least one of: the seal assembly comprises a mandrel; the seal support arrangement further comprises a limit ring mounted on the mandrel and configured to prevent or at least limit axial movement of the support elements, permitting the seal support deflector to be axially moved relative to the support elements; the seal support arrangement further comprises a limit ring mounted on the mandrel and configured to prevent or at least limit axial movement of the support elements, permitting the seal support deflector to be axially moved relative to the support elements, and wherein one or more of the support elements are initially secured relative to the limit ring via a releasable connection; the seal support deflector is engaged by the seal element, such that activation of the seal element to be extended by the setting arrangement causes the seal support deflector to be moved axially and thus extend the support elements; one end region of the seal element is engaged with the seal support deflector; and at least one support element is connected to the seal support deflector.

14. The seal assembly according to claim 11, wherein at least one of: at least one support element is rotatable about a pivot point to be moved to the extended configuration; at least one support element is rotatable about a pivot point to be moved to the extended configuration and the pivot point of at least one support element is located externally of the respective support element; the pivot point of at least one support element is located radially outwardly of a maximum outer dimension of the respective support element when in the extended configuration; and the pivot point of at least one support element is located radially outwardly of a wall of a bore within which the seal assembly is located.

15. The seal assembly according to claim 12, wherein one of: the support elements and seal support deflector define corresponding curved surfaces which inter-engage to permit the support elements to be rotated, and the support elements and seal support deflector define corresponding curved surfaces which inter-engage to permit the support elements to be rotated, and wherein at least one support element comprises a planar portion or surface which is contiguous with a curved surface and is arranged to be engaged with the mandrel when said support element is moved to an extended configuration.

16. The seal assembly according to claim 1, comprising a seal back-up arrangement extending over at least a portion of the outer surface of the seal element, and wherein one of: the seal back-up arrangement is interposed between the seal element and a seal support arrangement; and the seal back-up arrangement is interposed between the seal element and a seal support arrangement, and wherein the seal back-up arrangement is configured to span at least one circumferential gap between adjacent support elements of the seal support arrangement.

17. The seal assembly of claim 1 comprising the mandrel, wherein the radially expandable seal element is mounted on the mandrel, and the setting arrangement is mounted on the mandrel.

18. The seal assembly according to claim 17, wherein the seal element defines an annular gap with the mandrel.

19. The seal assembly according to claim 17, wherein one of: the setting arrangement is fluid actuated; and the setting arrangement is fluid actuated by fluid delivered via the mandrel, and wherein the mandrel defines one or more selectively openable fluid ports to permit fluid communication with the setting arrangement.

20. The seal assembly according to claim 17, wherein the mandrel includes a sleeve arrangement comprising inner and outer co-axially arranged sleeves, each defining one or more fluid ports, wherein in one configuration respective fluid ports in the sleeves are misaligned with each other, thus closing any communication path between the mandrel and the setting arrangement, and in another configuration, respective fluid ports of the sleeves are aligned, thus opening a communication path between the mandrel and the setting arrangement.

21. The seal assembly according to claim 20, wherein at least one of: the sleeves are actuated to move relative to each other to be reconfigured to selectively open the ports; the sleeve arrangement defines a staged activation procedure, with the sleeve arrangement being configured to initially open a port or set of ports to provide communication between the mandrel and the setting arrangement and thus permit setting of the seal element, and subsequent to this open a second port or set of ports to provide communication with an annulus surrounding the mandrel; the sleeve arrangement defines a staged activation procedure, with the sleeve arrangement being configured to initially open a port or set of ports to provide communication between the mandrel and the setting arrangement and thus permit setting of the seal element, and subsequent to this open a second port or set of ports to provide communication with an annulus surrounding the mandrel, and wherein the subsequent stage also closes the first port or set of ports.

22. The seal assembly according to claim 17, comprising a second seal element and a second setting assembly mounted on the mandrel.

23. A method for establishing or setting a seal within an annulus between a mandrel and a bore wall, the method comprising the steps of: running a seal assembly according to claim 1 into a bore, wherein the setting arrangement comprises a deflector operable to displace the seal element radially outwardly and an intermediate member interposed between the seal element and the deflector, the seal element, the intermediate member and the deflector being axially slidable relative to each other and the mandrel to position the deflector and the intermediate member between the seal element and the mandrel in a radially stacked configuration to affect the radial expansion of the seal element; and actuating the setting arrangement to move the deflector, intermediate member between the seal element in a radially stacked configuration to displace the seal element radially outward from a retracted configuration to an extended configuration to define a cup seal.

24. A seal assembly for establishing a seal in an annulus between a mandrel and a bore wall, comprising: a mandrel; a radially expandable seal element mounted on the mandrel; a seal support arrangement mounted on the mandrel and in engagement with the seal element; and a setting arrangement mounted on the mandrel and being arranged to displace the seal element radially outwardly from a retracted configuration to an extended configuration, and to cause the seal element to initiate radial extension of the seal support arrangement, wherein the setting arrangement comprises a deflector operable to displace the seal element radially outwardly and an intermediate member interposed between the seal element and the deflector, the seal element, the intermediate member and the deflector being axially slidable relative to each other and the mandrel is to position the deflector, and the intermediate member between the seal element and the mandrel in a radially stacked configuration to affect the radial expansion of the seal element, wherein the seal element comprises a fixed end region which is radially fixed, and an opposite free end region which is configured to be radially expanded by the setting arrangement.

25. A seal assembly for establishing a seal in an annulus between a mandrel and a bore wall, comprising: a mandrel; a radially extendable seal element mounted on the mandrel; a radially extendable seal support assembly; and a setting arrangement mounted on the mandrel, wherein the setting arrangement comprises a deflector operable to displace the seal element radially outwardly and an intermediate member interposed between the seal element and the deflector, the seal element, the intermediate member and the deflector being axially slidable relative to each other and the mandrel to position the deflector, and the intermediate member between the seal element and the mandrel in a radially stacked configuration to affect the radial expansion of the seal element, and wherein the seal element comprises a fixed end region which is radially fixed, and an opposite free end region which is configured to be radially expanded by the setting arrangement, wherein the seal element is interposed between the setting arrangement, and the extendable seal support assembly and the setting arrangement is configured to apply a setting force on the seal element, and in turn the seal element is configured to apply a setting force on the seal support assembly to radially extend both the seal element and the seal support assembly.

26. A seal assembly for establishing a seal in an annulus between a mandrel and a bore wall, comprising: a mandrel; a radially expandable seal element mounted on the mandrel; and a setting arrangement mounted on the mandrel and comprising an actuator and an intermediate member arranged between the actuator and the seal element, said actuator configured to drive the intermediate member axially beneath the seal element to radially stack the intermediate member and the seal element and cause the seal element to be expanded, wherein the setting arrangement comprises a deflector operable to displace the seal element radially outwardly and the intermediate member interposed between the seal element and the deflector, the seal element, the intermediate member and the deflector being axially slidable relative to each other and the mandrel to position the deflector and the intermediate member between the seal element and the mandrel in a radially stacked configuration to affect the radial expansion of the seal element, wherein the seal element comprises a fixed end region which is radially fixed, and an opposite free end region which is configured to be radially expanded by the setting arrangement.

27. An apparatus for sealing an annulus around a tubular member, the apparatus comprising: a tubular member; a deformable sealing element retained around the tubular member and having a sealing portion; a setting element slidably retained around the tubular member; the setting element operable to slide to a deployed position in which the setting element is between the tubular member and the sealing portion of the sealing element, to thereby increase an external diameter of the sealing portion, the setting element comprising a deflector operable to displace the seal element radially outwardly and an intermediate member interposed between the seal element and the deflector, the seal element, the intermediate member and the deflector being axially slidable relative to each other and the mandrel to position the deflector, and the intermediate member between the seal element and the mandrel in a radially stacked configuration to affect the radial expansion of the seal element, wherein the deformable sealing element comprises a fixed end region which is radially fixed, and an opposite free end region which is configured to be radially expanded by the setting arrangement.

28. An apparatus for sealing an annulus around a tubular member, the apparatus comprising: a tubular member; a deformable sealing element slidably retained around the tubular member; and a seal backup operatively engaged with the sealing element; the sealing element operable to slide between: a first position in which the sealing element is in a relaxed configuration and is operatively engaged with the seal backup in a retraced position; and a second position in which the sealing element is in a deformed configuration and is operatively engaged with the seal backup in an extended configuration, in which the seal backup supports at least a part of the sealing element; and a setting arrangement comprising a deflector operable to displace the seal element radially outwardly and an intermediate member interposed between the seal element and the deflector, the seal element, the intermediate member and the deflector and the intermediate member being axially slidable relative to each other and the mandrel to position the deflector between the seal element and the mandrel in a radially stacked configuration to affect the radial expansion of the seal element, wherein the deformable seal element comprises a fixed end region which is radially fixed, and an opposite free end region which is configured to be radially expanded by the setting arrangement.

29. A seal assembly for establishing a seal in an annulus between a mandrel and a bore wall, comprising: a mandrel; a deflector; an intermediate member; a radially expandable seal element mounted on the mandrel; and a setting arrangement mounted on the mandrel and being arranged to displace the seal element radially outwardly from a retracted configuration to an extended configuration, wherein the expandable seal element defines a cup seal when in the extended configuration, wherein the seal element, the intermediate member and the deflector are axially slidable relative to each other and the mandrel to position the deflector and the intermediate member between the seal element and the mandrel in a radially stacked configuration to affect the radial expansion of the seal element, wherein the mandrel includes a sleeve arrangement comprising inner and outer co-axially arranged sleeves, each defining one or more fluid ports, wherein in one configuration for running the seal assembly into a bore, respective fluid ports in the sleeves are misaligned with each other, thus closing any communication path between the mandrel and the setting arrangement, and in another configuration for radially expanding the seal element, respective fluid ports of the sleeves are aligned, thus opening a communication path between the mandrel and the setting arrangement.

30. The seal assembly according to claim 29, wherein at least one of: the sleeves are actuated to move relative to each other to be reconfigured to selectively open the ports; the sleeve arrangement defines a staged activation procedure, with the sleeve arrangement being configured to initially open a port or set of ports to provide communication between the mandrel and the setting arrangement and thus permit setting of the seal element, and subsequent to this open a second port or set of ports to provide communication with an annulus surrounding the mandrel; the sleeve arrangement defines a staged activation procedure, with the sleeve arrangement being configured to initially open a port or set of ports to provide communication between the mandrel and the setting arrangement and thus permit setting of the seal element, and subsequent to this open a second port or set of ports to provide communication with an annulus surrounding the mandrel, and wherein the subsequent stage also closes the first port or set of ports.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

(2) FIG. 1 is a cross-sectional view of a seal assembly, according to an embodiment of the present invention, shown in a retracted configuration;

(3) FIG. 2 is a cross-sectional view of the seal assembly of FIG. 1, shown in an extended configuration;

(4) FIG. 3 is an enlarged view of a seal back-up system which forms part of the seal assembly of FIG. 1, and the seal back-up system is shown in a retracted configuration;

(5) FIG. 4 shows the seal back-up system of FIG. 3, shown in an extended configuration;

(6) FIGS. 5A to 5E illustrate a tool which incorporates the seal assembly first shown in FIG. 1, shown in different stages of operation; and

(7) FIG. 6 shows a seal assembly according to a modified embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

(8) A cross-sectional view of a sealing assembly, generally identified by reference numeral 10, is shown in FIGS. 1 and 2, and the assembly 10 is shown in a retracted configuration in FIG. 1, and in an extended configuration in FIG. 2. The sealing assembly 10 may be used in multiple applications, and in the present embodiment is for use in providing a seal in an annulus 12 defined between the seal assembly 10 and a wall 14 of a wellbore. The bore wall 14 may be defined by an open drilled bore, a lined or cased bore, a pipe line or the like.

(9) The sealing assembly 10 includes a mandrel 16 which supports a radially expandable seal element 18 and a setting arrangement 20 which, as will be described in further detail below, is for use in displacing the seal element 18 radially outwardly from a retracted configuration (FIG. 1) to an extended configuration (FIG. 2) to engage and seal against the bore wall 14. The sealing assembly 10 further includes a seal support arrangement 22 which provides axial support to the seal element 18 when extended, as will also be described in further detail below.

(10) As shown in FIG. 1, the seal element 18 is generally cylindrical when in its retracted configuration, thus assisting to define a minimal outer diameter. This may assist in passing the seal assembly 10 through any restrictions to reach a target location within the bore. Further, as shown in FIG. 2, the seal element 18 defines a cup seal form when in its extended configuration. Accordingly, when the seal element 18 is extended it responds to a pressure differential across the seal (and P1>P2) to establish and/or enhance a seal with the bore wall 14. As such, the present invention benefits from both the ability to radially expand the seal element 18, and from the seal element 18 functioning as a cup seal when in the extended configuration.

(11) The setting arrangement 20 includes an annular ram 23, a deflector 24 mounted or engaged with an end of the ram 23, and an intermediate member 26 which is interposed between the deflector 24 and the seal element 18. The deflector 24 includes a ramp surface 28 which interengages a corresponding ramp surface 30 formed on one end of the intermediate member 26. An opposite end of the intermediate member 26 also includes a ramp surface 32, which inter-engages a corresponding ramp surface 34 formed on a free end region 36 of the seal element 18. An opposite axial end of the seal element 18 defines a fixed end region 38 which is secured and sealed with the seal support arrangement 22, such that this fixed end 38 is restrained against radial expansion.

(12) In use, the ram 23 is hydraulically actuated to stroke axially, such that interengagement of the various ramp surfaces 28, 30, 32, 34 cause the deflector 24, intermediate member 26 and the free end 36 of the seal element 18 to become radially stacked, one on top of the other, thus effecting radial expansion of the seal element 18. As the end region 38 of the seal element 18 is radially fixed, the seal element 18 is deformed by the setting arrangement 20 to define a cup shape. Further, the presence of the ramp surface 34 on the free end region 36 of the seal element 18 permits this end region 36 to be spaced from the intermediate member 26 when in the extended configuration, thus allowing the seal element 18 to better function as a cup seal.

(13) The presence of the intermediate member 26 enables the seal element 18 to define a significant expansion ratio. In this respect, in other embodiments multiple intermediate members may be provided to increase the possible expansion ratio.

(14) The ram 23 is hydraulically actuated by fluid which is delivered via the mandrel 16 into a piston chamber 40 via fluid ports 42. As will be described in more detail below, the mandrel includes outer and inner coaxially arranged sleeves 16a, 16b which each define radial ports 42a, 42b. The sleeves 16a, 16b may be arranged such that the respective ports 42a, 42b are offset from each other, thus closing any communication between the mandrel 16 and the piston chamber 40. The sleeves 16a, 16b may be capable of being moved relative to each other to align the respective ports 42a, 42b to permit communication between the mandrel 16 and the piston chamber 40.

(15) As noted above, the seal assembly 10 further includes a seal support arrangement 22, which is expanded to provide axial support to the seal element 18. Such axial support may assist the seal element 18 to resist extrusion caused by a pressure differential in the annulus 12 across the seal.

(16) Enlarged views in the region of the seal support arrangement 22 are shown in FIGS. 3 and 4, reference to which is now made, and FIG. 3 shows the support arrangement in a retracted configuration, and FIG. 4 shows the support arrangement in an extended configuration.

(17) The seal support arrangement includes a plurality of support members 50 which are arranged circumferentially around the mandrel 16, and each member 50 defines a lower or inner surface which includes a curved portion 52 and a substantially planer portion 52a which is rearward of and contiguous with the curved portion 52. The seal support arrangement 22 also includes a support member deflector 54 in the form of a ring which is mounted around the mandrel 16 and is sealed relative thereto via an o-ring 56. The fixed end 38 of the seal element 18 is secured to the deflector 54 such that any force applied through the seal element 18 may be directed into the deflector 54. The deflector 54 also defines a curved surface 57, which is arranged to cooperate with the curved surface 52 of each member 50. Each member 50 includes a slot 58 in the respective curved surfaces 52 which are arranged to be secured to the deflector 54 via respective screws 60. The connection between the slots 58 and screws 60 is such that the curved surfaces 52, 57 may slide relative to each other, but are prevented from separation.

(18) The seal support arrangement 22 further includes an end ring 62 which is secured to the mandrel 16 and functions as a no-go to restrict axial movement of the members 50, and to provide a reaction point for the force applied by the ram 23 (FIGS. 1 and 2). The individual members 50 are initially secured to the end ring 62 via respective shear screws 63 such that the members 50 are positively held in the retracted configuration. Upon application of a suitable setting force the screws 63 will shear and permit the members 50 to become extended.

(19) In use, the setting force applied by the ram 23 of the setting arrangement 20 will be transmitted to the deflector 54 via the seal element 18, causing the deflector 54 to be displaced axially along the mandrel 16, such that inter-engagement of the curved surfaces 52, 57 of the members 50 and the deflector 54 will cause the members 50 to rock or pivot and be extended radially outwardly, following shearing of the respective shear screws 63. When extended, the members 50 may provide axial support to the seal element 18, as shown in FIG. 4. As illustrated in the present embodiment, the members 50 may physically engage the seal element 18 when extended.

(20) When the members 50 are fully extended, as shown in FIG. 4, the respective planer portions 52a become engaged with the outer surface of the mandrel 16. Further, the end ring 62 defines a profile, which compliments the profile of the members 50 when fully extended. This arrangement may provide robust support to the members 50 when in their extended configuration. For example, this may assist to prevent over rotation or extension of the members 50, for example to prevent pivoting of the members about a tip portion 62a of the end ring 62, which may otherwise occur in the event of continued axial forces applied by a contained pressure differential across the seal. Also, this arrangement may minimize the forces applied on the screws 60, as the screws may not be entirely responsible for retaining the members 50 in place when extended.

(21) The form of the members 50 and deflector 54 is such that the members 50 are caused to pivot about respective pivot axes, which are removed or located externally of the members 50. In such an arrangement, the pivot points may be defined as virtual or effective pivot points. As an example in FIGS. 3 and 4, a pivot point 64 of the upper most illustrated member 50 is shown, which as noted above is located externally of the member 50. In particular, this pivot point 64 (and the pivot points of all the members 50) is located radially outwardly of the maximum extended dimension of the members 50, which may be defined by the bore wall 14. Such a selected location of the pivot point 64 may permit the members 50 to be biased to move towards a retracted configuration in the event of snagging or engaging an object in the bore annulus 12 in any direction. As such, when the sealing assembly 10 is being run through a bore in any direction, any snagging of an extended member 50 with an object in the bore will cause the member 50 to move towards its retracted configuration, thus permitting the seal assembly 10 to continue through the bore.

(22) The sealing assembly 10 may be used in many applications where an annular bore seal is required. One such example will now be described with reference to FIGS. 5A to 5E, which illustrate a tool, generally identified by reference numeral 70, which incorporates multiple seal assemblies of the type described above, and the tool 70 is shown in different stages of operation.

(23) The tool 70 includes two axially spaced sealing assemblies 10A, 10B which are similar to the sealing assembly 10 described above, and as such no further specific description will be given. However, generally, each sealing assembly 10A, 10B includes a seal element 18A, 18B, a setting arrangement 20A, 20B and a seal support arrangement 22A, 22B, all mounted on a common mandrel 16. The sealing assemblies 10A, 10B are arranged in back-to-back relationship with each other.

(24) The common mandrel 16, as above, includes outer and inner coaxially arranged sleeves 16a, 16b. The outer sleeve 16a may define a portion of a tubing string, and may facilitate connection of the tool 70 to a tubing string, work string or the like. The outer sleeve 16a defines upper and lower seal setting ports 72a, and intermediate wash ports 74a, and the inner sleeve 16b defines corresponding upper and lower seal setting ports 72b, and intermediate wash ports 74b. As will be described in further detail below, relative movement between the sleeves 16a, 16b will cause the various ports to be selectively aligned and misaligned, thus providing appropriate control of the tool 70.

(25) The inner sleeve 16b includes a seat portion 76 mounted on an inner surface thereof, and the outer sleeve includes first, second and third collars 78, 80, 82 axially spaced along and secured to its inner surface.

(26) When the tool 70 is configured in its initial configuration, as illustrated in FIG. 5A, which is suitable for running into a bore (not shown) to the required depth, the seal assemblies 10A, 10B are fully retracted and the various ports 72a, 72b, 74a, 74b, 76a, 76b are all misaligned such that fluid communication through the wall of the mandrel 16 is prevented. Further, the lower end of the inner mandrel sleeve 16b, and specifically the seat 76, is located against the first collar 78.

(27) When the tool 70 is to be activated to set the seal assemblies 10A, 10B a ball 84 is dropped through the mandrel 16 until the ball 84 sealingly engages the seat 76, as illustrated in FIG. 5B. This permits pressure within the mandrel 16 to be elevated to a level which shears the first collar 78 from the outer sleeve 16a, causing the inner sleeve 16b to move downwardly relative to the outer sleeve 16a until the sheared first collar 78 engages the second collar 80, as illustrated in FIG. 5C. At this point, the seal setting ports 72a, 72b of the sleeves 16a, 16b are aligned, thus permitting fluid to be communicated with the setting arrangement 20A, 20B of each sealing assembly, allowing the seal elements 18A, 18B to be extended, along with the respective seal support arrangements 22A, 22B, as illustrated in FIG. 5D. It will be noted that at this stage the wash ports 74a, 74b of the sleeves 16a, 16b remain misaligned and thus closed.

(28) Once the sealing assemblies 10A, 10B are appropriately set, pressure may again become elevated within the mandrel 16 until the second collar 80 is sheared from the outer sleeve 16a, thus permitting further downward movement of the inner sleeve 16b until the second collar 80 engages the third collar 82, as illustrated in FIG. 5E. This downward movement may cause the seal setting ports 72a, 72b to become misaligned and thus closed, assisting to retain the sealing assemblies 10A, 10B in their extended configuration. Furthermore, such further downward movement of the inner sleeve 16b will permit the wash ports 74a, 74b to become aligned and thus opened to permit communication of fluid from within the mandrel into the isolated section of a bore between the sealing assemblies 10A, 10B. This wash fluid may be used for any required purpose, such as for a treating purpose, for example acid stimulation, f racing or the like. Alternatively, or additionally, this wash fluid may be used to increase the pressure in the bore between the sealing assemblies 10A, 10B to enable the cup sealing functionality to improve the set seals.

(29) In the sealing assembly 10 first shown in FIG. 1, the support arrangement 22 functions to axially support the seal element 18, for example to assist in preventing extrusion of the seal element 18 along the annulus 12 when exposed to elevated pressure differentials. In some embodiments, to further assist with seal support, a seal back-up assembly may be used, which will now be exemplified with reference to FIG. 6.

(30) FIG. 6 illustrates a seal assembly 10 of almost identical form to that shown in FIG. 1, and as such like components share like reference numerals. As such, the assembly 10 includes a seal element 18, a setting arrangement 20 and a support arrangement 22. As before, the setting arrangement includes a deflector 24 and an intermediate member 26. Also, the support arrangement 22 includes a plurality of support members 50, a deflector 56 and an end ring 62. No further description of these components will be given.

(31) In this modified embodiment the apparatus 10 further includes a seal back-up assembly 100, which extends over one end of the seal element 18, and is positioned intermediate the seal element and the support arrangement 22. The back-up assembly 100 is of a petal type, and includes a plurality of circumferentially arranged petals 102 which extend over an outer surface of the seal element 18. As the seal element 18 is expanded, as shown in FIG. 2, these petals 102 also expand, and become engaged by the individual members 50 of the support arrangement 22.

(32) The petals 102 are arranged such that they are each aligned with a circumferential gap 104 between adjacent members 50. Thus, the petals 102 may bridge such gaps 104 and as such, further assist in preventing extrusion of the seal element 18 when in use.

(33) It should be understood that the embodiments described above are merely exemplary and that various modifications may be made thereto without departing from the scope of the invention.

(34) The foregoing description is only exemplary of the principles of the invention. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, so that one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.