DOWNHOLE SEALING APPARATUS AND METHOD

Abstract

A downhole sealing apparatus having a sealing assembly with one or more seal elements configured to engage a bore wall or bore-lining tubular wall to seal an annulus between the apparatus and the wall or tubular wall. A bypass arrangement is configured to provide selective bypass of the sealing assembly and the sealing apparatus is reconfigurable between a first configuration permitting bypass of the sealing assembly and a second configuration in which the bypass arrangement prevents or restricts bypass of the sealing assembly. A downhole method provides the downhole sealing apparatus within a bore hole, with the downhole sealing apparatus reconfigured from the first configuration in which the bypass arrangement permits bypass of the sealing assembly to a second configuration in which the bypass arrangement prevents or restricts bypass of the sealing assembly.

Claims

1. A downhole sealing apparatus comprising: a sealing assembly having one or more seal elements configured to engage a bore wall or bore-lining tubular wall so as to seal an annulus between the downhole sealing apparatus and said bore wall or bore-lining tubular wall; and a bypass arrangement configured to provide selective bypass of the sealing assembly, wherein the downhole sealing apparatus is reconfigurable between a first configuration in which the bypass arrangement permits bypass of the sealing assembly and a second configuration in which the bypass arrangement prevents or restricts bypass of the sealing assembly.

2. The downhole sealing apparatus of claim 1, wherein the downhole sealing apparatus is configured to be reconfigurable from the first configuration to the second configuration by movement of the sealing assembly.

3. The downhole sealing apparatus of claim 1, wherein the sealing assembly comprises a pressure-activated sealing assembly.

4. The downhole sealing apparatus of claim 2, wherein the sealing assembly may be configured to be movable relative to the mandrel reconfigure the downhole sealing apparatus from the first configuration to the second configuration.

5. The downhole sealing apparatus of claim 4, wherein the sealing assembly is axially movable relative to the mandrel.

6. The downhole sealing apparatus of claim 1, wherein the bypass arrangement comprises a sleeve configured for mounting on a mandrel.

7. The downhole sealing apparatus of claim 1, wherein the bypass arrangement comprises a fluid passage, wherein when the sealing apparatus is in the first configuration, fluid may flow through the fluid passage and when the sealing apparatus is in the second configuration, the fluid passage may be closed.

8. The downhole sealing apparatus of claim 7, wherein the fluid passage comprises a first end and a second end, and the bypass arrangement is positioned such that the first and second ends of the fluid passage straddle the sealing assembly.

9. The downhole sealing apparatus of claim 1, wherein the bypass arrangement further comprises a biasing mechanism.

10. The downhole sealing apparatus of claim 9, wherein the biasing mechanism is configured to bias the sealing apparatus to the first configuration.

11. The downhole sealing apparatus of claim 9, wherein the biasing mechanism comprises a spring.

12. The downhole sealing apparatus of claim 1, further comprising a second sealing assembly.

13. The downhole sealing assembly of claim 12, wherein the second sealing assembly is arranged to be back-to-back with the sealing assembly.

14. The downhole sealing assembly of claim 12, wherein the bypass arrangement is positioned in between the sealing assembly and the second sealing assembly and is operable to selectively bypass one or both of the sealing assembly and the second sealing assembly.

15. The downhole sealing assembly of claim 12, further comprising a second bypass arrangement configured to provide selective bypass of the second sealing assembly.

16. A downhole method comprising the steps of: providing a downhole sealing apparatus according to claim 1 within a borehole; and reconfiguring the downhole sealing apparatus from the first configuration in which the bypass arrangement permits bypass of the sealing assembly to a second configuration in which the bypass arrangement prevents or restricts bypass of the sealing assembly.

17. The method of claim 16, further comprising the step of locating the downhole sealing apparatus downhole.

18. The method of claim 16, comprising the step of applying a differential pressure to the downhole sealing apparatus to reconfigure the sealing apparatus from the first configuration to the second configuration.

19. The method of claim 16, further comprising the step of activating the sealing assembly to form a seal with a bore wall when the bypass arrangement is in the second configuration.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] These and other aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0041] FIG. 1 is a longitudinal cross-sectional view of a downhole sealing apparatus on a mandrel with an open bypass arrangement;

[0042] FIG. 2 is an enlarged view of the open bypass arrangement;

[0043] FIG. 3 is a cross-sectional view of a downhole sealing apparatus on a mandrel with a closed bypass arrangement;

[0044] FIG. 4 is an enlarged view of the closed bypass arrangement;

[0045] FIG. 5 is a cross-sectional view of a downhole sealing apparatus having multiple sealing assemblies;

[0046] FIG. 6 is a cross-sectional view of a downhole sealing apparatus having multiple sealing assemblies and bypass arrangements; and

[0047] FIG. 7 is a cross-sectional view of a bypass arrangement.

[0048] A downhole sealing apparatus 10 is shown in FIG. 1 of the accompanying drawings. The downhole sealing apparatus 10 comprises a sealing assembly, generally denoted 14, which in the illustrated apparatus 10 is in the form of a cup sealing assembly. The sealing assembly 14 comprises a sealing element 16 and a support member 18. The support member 18 may comprise a seal 38, for example an O-ring, which is provided in an annular groove in the support member 18. It will be appreciated that any form of sealing assembly may be utilised in the downhole sealing apparatus 10, particularly sealing assemblies which form a seal upon exposure to a pressure differential, such as cup sealing assemblies. The sealing assembly 14 is positioned on a mandrel 12 for location downhole.

[0049] The downhole apparatus 10 further comprises a bypass arrangement 30. The bypass arrangement 30 comprises a biasing mechanism in the form of a series of disc springs 36 which bias the downhole sealing apparatus to a first configuration in which the sealing assembly 14 can be bypassed. Any form of spring may be used in order to provide the desired biased arrangement. The bypass arrangement 30 comprises a flow passage 34 (in the form of a slot) wherein the flow passage permits fluid communication between a first portion of the annulus and a second portion of the annulus, when the sealing apparatus is located downhole. Multiple flow passages may be provided.

[0050] The bypass arrangement comprises a radially outwardly extending flange 33. The biasing mechanism is configured to be positioned between the sealing assembly 14 and the flange 33. In some examples, the bypass arrangement comprises a bypass sleeve 32 configured for mounting on the mandrel 12 (FIG. 7). Alternatively, the bypass arrangement 30 may form part of the mandrel itself whereby the flow passages 34 are formed in the mandrel 12 (not shown).

[0051] In use, the downhole sealing apparatus 10 can be located downhole. Whilst running downhole, or prior to forming a seal using the sealing assembly 14, the bypass arrangement 30 biases the apparatus to the first configuration whereby a nominal pressure difference can bypass the sealing assembly 14 by virtue of the flow path provided through the flow passage 34. This prevents the accidental activation of the sealing assembly 14. For example, an issue with prior art sealing assemblies can occur when the assembly is run in hole too quickly resulting in a build-up of pressure which can accidently activate the sealing assembly and result in damage to the sealing assembly. The provision of the bypass arrangement, which permits the sealing assembly to be bypassed, should allow an operator to run the apparatus downhole without accidentally activating the sealing assembly.

[0052] When it is desired to activate the sealing assembly 14, a higher pressure differential may be applied to the downhole sealing apparatus 10, for example by increasing an applied flow rate. The increase in pressure differential axially moves the sealing assembly 14 relative to the mandrel to reconfigure the downhole sealing apparatus 10 into the second configuration (FIGS. 3 and 4) in which the bypass arrangement prevents bypass of the sealing assembly 14. Under the increased pressure differential, the sealing assembly 14 compresses the disc springs 36 of the bypass arrangement 30 and closes the flow passage 34. The pressure differential required to reconfigure the downhole apparatus from the first to the second configuration may be determined by operational requirements. For example, the pressure differential required may be the same or slightly less than the pressure differential required to activate the sealing assembly 14. The pressure differential required to reconfigure the downhole apparatus may be determined by the spring force of the disc springs 36 and/or the volume of the flow passage 34.

[0053] With the downhole sealing apparatus 10 in the second configuration, the sealing assembly 14 may be activated to form a seal with a bore wall. As shown in the figures, the sealing assembly 14 may be in the form of a cup sealing assembly, wherein the seal element 16 is configured to expand under a pressure differential to form a seal with a bore wall.

[0054] A further downhole sealing apparatus 100 is shown in FIG. 5. The downhole apparatus 100 comprises a first sealing assembly 113 and a second sealing assembly 114 configured to be positioned on a mandrel 112 in a back-to-back arrangement. A bypass arrangement 130 is provided between the first and second sealing assemblies 113, 114. The bypass arrangement 130 is biased to a first configuration in which flow passages 134, 135 are open to allow a nominal pressure differential to bypass the sealing assemblies 113, 114. The bypass arrangement 130 is configured such a differential pressure in at least one direction will move the respective sealing assembly 113, 114 to close the respective flow passage 134, 135 and prevent bypass of the sealing assembly 113, 114.

[0055] A further downhole sealing apparatus 100 is shown in FIG. 6. The downhole apparatus 200 comprises a first sealing assembly 213 and a second sealing assembly 214 configured to be positioned on a mandrel 212 in a back-to-back arrangement. A first bypass arrangement 230 is arranged to provide selective bypass of the sealing assembly 213 and a second bypass arrangement 231 is arranged to provide selective bypass of the sealing assembly 214.

[0056] It should be understood that the examples provided herein are merely exemplary of the present disclosure and that various modifications may be made thereto without departing from the scope defined by the claims.