GB2540214A

GB2540214A - Completion Plug Assembly & Method

Info

Publication number: GB2540214A
Application number: GB1512136.1A
Authority: GB
Inventors: George Bowie Angus
Original assignee: Stats UK Ltd
Current assignee: Stats UK Ltd
Priority date: 2015-07-10
Filing date: 2015-07-10
Publication date: 2017-01-11
Anticipated expiration: 2035-07-10
Also published as: GB2540214B; GB201512136D0

Abstract

A plug assembly 10, such as a completion plug, comprises a plug member 14 with a lock arrangement 16 used in securing the plug member 14 to a pipe section 12, such as a branch or flange connection. It also comprises a seal arrangement 18 engaging the pipe section 12 and a probe 20 disposed in and coupled to the plug member 14. The probe 20 is coupled to the plug member 14 via a manifold 22 and provides fluid communication to the plug member 14. The assembly provides sealing and a secure restraint without breaching the permanent pressure boundary. Fluid communication of pressurized hydraulic or pneumatic fluid for example, via the probe 20 permits operation of the plug assembly 10 within a sealed and pressurized environment. The fluid communication to the plug member 14 actuates the lock arrangement 16, applies a test pressure to the seal arrangement 18 and/or disconnects the probe 20 from the plug member 14, via an optional plurality of fluid conduits in the probe 20.

Description

COMPLETION PLUG ASSEMBLY & METHOD

FIELD

This invention relates to a plug assembly and method. More particularly, but not exclusively, embodiments of the invention relate to a completion plug assembly and a method for plugging a conduit.

BACKGROUND

In many industries, pipes and pipelines are used to transport fluid over distance, often in environments where access to the pipe is limited or restricted. In some situations, it may be necessary or desirable to gain access to a “live” section of pipe, that is, containing flowing fluid at pressure, in order to isolate a section of the pipe for repair, replacement or to permit deployment of tooling into the pipe.

One technique widely used for gaining access to a live section of a pipe is known as hot tapping. Hot tapping involves the fitting of a branch or tee connection to the pipe, the hot tap connection then being fitted with a valve through which a tapping or drilling tool may be directed to form a penetration in the pipe while maintaining pressure integrity. On completion of the drilling process, the tapping tool is removed and the valve closed to complete the branch connection. Operation of the valve then permits selective access into or from the branch connection for fluid or tooling.

In some circumstances, it may be necessary or desirable to remove the hot tap valve and replace this with a closure, such as a blind flange or the like. Conventionally, this involves locating a plug, known as a completion plug, in the branch below the valve. Once the plug is set, the valve can be removed.

However, as International safety and operational codes and standards have developed, existing techniques and completion plug technology in many cases no longer meets the required standards. Moreover, conventional completion plugs have screw holes through the primary boundary of the weld neck flange which can cause integrity issues, particularly when used for extended periods of time. In such situations, it is necessary to perform remedial or workover operations to repair or replace the plug which, due to the remote or inaccessible location, can be difficult and incur significant expense to an operator.

SUMMARY

According to a first aspect, there is provided a plug assembly comprising: a plug member comprising a seal arrangement for sealingly engaging a section of pipe; a lock arrangement for securing the plug member to the section of pipe; and a probe configured to provide fluid communication to the plug member to at least one of: actuate the lock arrangement; apply a test pressure to the seal arrangement; and/or disconnect the probe from the plug member.

In use, the plug assembly may be deployed into a section of pipe and the lock arrangement actuable to secure the plug member to the pipe.

In particular embodiments, the plug assembly may comprise a completion plug assembly, that is a plug assembly for deployment into a section of pipe, such as a pipe branch or flange connection, and which is operable to isolate the branch or flange to facilitate the removal of a valve, such as a hot tap valve, for repair or replacement.

Beneficially, this invention provides dual sealing and a secure restraint without breaching the permanent pressure boundary. Providing a plug assembly in which fluid communication is via the probe permits operation of the plug assembly within a sealed and pressurised environment. Moreover, providing a plug assembly in which fluid communication is via the probe permits the lock arrangement of the plug assembly to be disposed in, and deployed from, the plug member. The pipe section into which the plug assembly is deployed - which in many applications is a permanent fixture - may thus be simpler in construction since no external penetrations are required for the lock arrangement or to facilitate lock actuation. The lack of external penetrations through the pipe section has the added benefit that it provides improved pressure integrity, and so eliminates or at least mitigates the integrity issues associated with conventional equipment. Providing a plug assembly in which fluid communication is via the probe also permits additional functionality, for example by permitting a pressure test or seal integrity test to be applied to the seal arrangement of the plug assembly.

The plug assembly may be fluid actuable or fluid powered, that is the probe may be configured to provide communication of pressurised hydraulic or pneumatic fluid to the plug member. In such embodiments, the pressurised fluid is isolated from fluid transported through the pipe section and provides for operation of the plug assembly irrespective of fluid pressure in the pipe. In particular embodiments, the plug assembly is hydraulically powered. A fluid conduit, and in particular embodiments a plurality of fluid conduits, may be formed or provided in the probe to facilitate fluid communication to the plug member. At least one fluid conduit may provide fluid communication to the lock arrangement to facilitate activation and/or deactivation of the lock arrangement. At least one fluid conduit may provide fluid communication to the seal arrangement to facilitate a pressure test of the seal arrangement. At least one fluid conduit may provide fluid communication to facilitate disconnection of the probe from the plug member. A connection arrangement may be provided for connecting the probe to at least one flow line, such as a hydraulic flow line. The connection arrangement may, for example, comprise at least one port or fitting formed in, or disposed in, the probe. The plug assembly may comprise, or may be provided in combination with, the at least one flow line. A probe housing may be configured for locating the probe into the plug member. For example, the probe may comprise or define a male portion for location in a corresponding female portion of the plug member. The probe may alternatively or additionally comprise or define a female portion for location on a corresponding male portion of the plug member. While it is envisaged that the probe and the plug member may be coupled when deployed into the pipe section, the provision of a male and/or female portion assists in locating the probe in the plug member where it is desired to reconnect the probe to the plug member where required. The configuration, shape or form of the male and/or female portion may also assist in ensuring the flow conduit or conduits of the probe are correctly aligned with the plug member. A coupling arrangement may be provided for coupling the probe to the plug member. The coupling arrangement may be configured to detachably couple the probe to the plug member. The coupling arrangement may be of any suitable form and construction. In particular embodiments, the coupling arrangement is fluid actuated. For example, the coupling arrangement may comprise a fluid piston. In use, pressurised fluid may be directed via the at least one fluid conduit provided to facilitate disconnection of the probe from the plug member to urge the fluid piston to move from a first position to a second position, in said second position the probe being released from the plug member. The coupling arrangement may comprise a collet or sleeve. The collet or sleeve may comprise or define the fluid piston of the coupling arrangement. The coupling arrangement may further comprise at least one retainer element, such as a ball. In use, movement of the fluid piston from its first position to its second position permits the retainer element or elements to move to a position in which the probe is released from the plug member.

The probe may comprise a hydraulic hot stab.

The plug member may be adapted for location in the pipe and may be of any suitable form and construction.

At least one flow passage may be formed or provided in the plug member.

At least one flow passage may be formed or provided in the plug member to communicate fluid to the lock arrangement.

At least one flow passage may be formed or provided in the plug member to communicate fluid to the seal arrangement.

The plug member may be configured to receive the lock arrangement of the plug assembly. For example, the plug member may comprise one or more recess for receiving the lock arrangement.

The plug assembly may be configured to provide selective fluid communication to the seal arrangement. For example, the plug assembly may comprise a check valve. The check valve may be received in the plug member. In use, the check valve permits isolation of the flow passage associated with seal arrangement to be maintained following decoupling of the probe from the plug member.

The plug assembly may comprise a manifold. The manifold may be integrally formed with the plug member. Alternatively, the manifold may comprise a separate component or subassembly from the plug member. In embodiments where the manifold comprises a separate component or subassembly, the manifold may be coupled to the plug member. The manifold may, for example, be disposed within, and may extend from, a recess in the plug member.

The provision of a manifold beneficially simplifies construction of the plug member. For example, the check-valve may be housed in the manifold of the plug assembly. Alternatively or additionally, the probe may be coupled to the plug member via manifold.

The lock arrangement secures the plug assembly to the pipe and may be of any suitable form and construction.

The lock arrangement may comprise at least one lock member. In use, the lock member or members are actuable to engage the pipe section.

In particular embodiments, the lock arrangement is fluid actuated. For example, the lock arrangement may comprise one or more fluid piston. In use, pressurised fluid may be directed via the at least one fluid conduit provided to facilitate activation of the lock arrangement to urge the fluid piston or pistons to move from a first position to a second position, in said second position the lock members secure the plug assembly to the pipe section.

The lock arrangement may comprise a single lock member. However, in particular embodiments, the lock arrangement comprises a plurality of lock members. The lock members may comprise lock segments, lock dogs or the like. The lock members may be circumferentially arranged. The lock members may be circumferentially spaced.

The seal arrangement facilitates sealing between the plug member and the pipe and may be of any suitable form and construction.

The seal arrangement may comprise at least one seal element disposed on the plug member. In particular embodiments, the seal arrangement comprises a plurality of seal elements. The at least one flow passage formed or provided in the plug member to communicate fluid to the seal arrangement may be disposed between the seal elements. In use, fluid may be communicated to said flow passage to permit the integrity of one or both of the seal elements to be tested, such that the plug assembly meets double block and bleed operational and safety standards.

At least one seal element of the seal arrangement may comprise an elastomeric seal element.

At least one seal element of the seal arrangement may comprise a metallic seal element. In particular embodiments, the metallic seal element may comprise a primary seal element of the seal arrangement. In use, the metallic seal element may elastically deflect to provide seal energisation.

The plug assembly may further comprise a deployment arm. In use, the deployment arm facilitates handling of the plug assembly.

As outlined above, the plug assembly is configured for deployment into a section of pipe and in particular embodiments, the section of pipe is configured to receive the plug assembly. For example, the section of pipe may comprise a receiver for receiving the lock arrangement of the plug assembly. The receiver may for example comprise a recess or groove. In particular embodiments, the receiver may comprise an annular recess or groove. In other embodiments, a receiver for receiving the plug assembly may be provided. The receiver may be coupled to the pipe, for example by a welded connection, by mechanical fastening, such as bolts, or the like. The receiver may comprise a pipe extension secured to an end of the pipe, a collar disposed within the existing pipe section, or an isolation tool. In embodiments where the pipe section comprises a flanged connection, the receiver may comprise a sandwich flange or the like.

According to a second aspect there is provided a method comprising: providing a plug assembly comprising: a plug member comprising a seal arrangement for sealingly engaging the section of pipe; a lock arrangement for securing the plug member to the section of pipe; and a probe configured to provide fluid communication to the plug member; and communicating fluid to the plug member via the probe to at least one of: actuate the lock arrangement; apply a test pressure to the seal arrangement; and/or disconnect the probe from the plug member.

According to a third aspect, there is provided a probe according to the first aspect.

It should be understood that the features defined above in accordance with any aspect of the present invention or below in accordance with any specific embodiment may be utilised, either alone or in combination with any other defined feature, in any other aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

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

Figure 1 shows a cross sectional view of a plug assembly according to an embodiment of the invention;

Figure 2 shows an enlarged view of the probe of the plug assembly shown in Figure 1

Figure 3 shows the plug assembly shown in Figure 1, disposed in the pipe section;

Figure 4 shows the plug assembly shown in Figures 3, with the lock arrangement of the plug assembly engaged with the pipe section:

Figure 5 shows the plug assembly shown in Figures 3 and 4, with the probe of the plug assembly detached;

Figure 6 shows the plug assembly shown in Figures 3 to 5, with a blind flange attached to the pipe section; and

Figure 7 shows part of a plug assembly according to a second embodiment of the invention, utilising an alternative lock arrangement.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring first to Figure 1 of the accompanying drawings, there is shown a cross-sectional view of a plug assembly 10 according to an embodiment of the present invention. In use, the plug assembly 10 is deployed into a section of pipe 12 and secured to the pipe 12 to permit an operation to be carried out. In the illustrated embodiment, the plug assembly 10 takes the form of a completion plug assembly and the pipe 12 takes the form of a branch or flange connection (see Figures 3 to 6), the plug assembly 10 being deployed into and secured to the flange connection in order to facilitate the removal of a valve, such as a hot tap valve, for repair or replacement.

As shown in Figure 1, the plug assembly 10 comprises a plug member 14 having a lock arrangement 16 for use in securing the plug member 14 to the pipe section 12 and a seal arrangement 18 for sealingly engaging the pipe section 12. A probe 20, which in the illustrated embodiment takes the form of a hydraulic hot stab, is disposed in and coupled to the plug member 14. In use, the probe 20 provides fluid communication to the lock arrangement 16 in order to actuate the lock arrangement 16, and provides fluid communication to the seal arrangement 18 to permit seal integrity to be tested. The probe 20 may be directly coupled to the plug member 14. However, in the illustrated embodiment the probe 20 is coupled to the plug member 14 via a manifold 22. The probe 20 is detachably coupled to the plug member 14 (in the illustrated embodiment via the manifold 22) and, in use, the probe 20 also provides fluid communication to a coupling arrangement 24 in order to release the coupling arrangement 24 and thereby release the probe 20 from the plug member 14.

As described above, the plug member 14 is configured for location in the pipe 12 and in the illustrated embodiment is disc shaped, having a size and shape such that the seal arrangement 18 sealingly engages the bore of the pipe section 12 when the plug assembly 10 is disposed in the pipe section 12. The disc shaped plug member 14 defines a suitable closure for the pipe section 12, having a strength equivalent to a blind flange (such as shown in Figure 6) and with similar factors of safety defined by pipeline codes. A number of radially drilled bores 26 are formed in the plug member 14. In use, the bores 26 define flow passages for communicating hydraulic fluid from the probe 20 (via the manifold 24) to the lock arrangement 16.

As shown in Figure 1, the lock arrangement 16 is disposed in the plug member 14 and comprises a number of circumferentially arranged shear segments or dogs 28. Each dog 28 is coupled to or defines a piston 30 disposed in a respective one of the drilled bores 26. Seal elements 32, such as o-rings, are disposed in seal grooves 34 in each piston 30. In use, pressurised fluid directed to the drilled bores 26 via the probe 20 drive the pistons 30 and dogs 28 radially outwards into engagement with the pipe 12 as described further below.

In addition to the bores 26, the plug member 14 further comprises a number of radially drilled bores 36. In use, the bores 36 define flow passages for communicating hydraulic fluid from the probe 20 (via the manifold 24) to the seal arrangement 18.

The seal arrangement 18 is housed in the plug member 14 and in the illustrated embodiment comprises a dual seal arrangement having a primary seal element 38 and a secondary seal element 40. As shown in Figure 1, the primary seal element 38 is disposed in an annular recess or seal groove 44 in an outer circumferential surface 46 of the plug member 14 and the secondary seal element 40 is disposed in an annular recess or seal groove 48 in the surface 46. The seal elements 38, 40 straddle the drilled bores 36. The dual seal arrangement permits the integrity of each of the primary and secondary seal elements 38, 40 to be independently verified, in compliance with the double block and bleed operational standards required for operation in safety critical systems. The seal arrangement 18 also comprises a tertiary seal element 50 disposed in an annular recess or seal groove 52 in the surface 46 of the plug member 14.

Referring now also to Figure 2 of the accompanying drawings, there is shown an enlarged view of the probe 20 and the manifold 22 of the plug assembly 10. As shown in Figure 2, the probe 20 comprises a housing having a first body portion 54 and a second body portion 56, the second body portion 56 defining a male portion of the probe 20 for coupling the probe 20 to the plug member 14 (in the illustrated embodiment via the manifold 22).

Fluid conduits 58, 60, 62, 64 and 66 are formed in the probe 20 and, in use, the fluid conduits 58, 60, 62, 64 and 66 provide hydraulic fluid communication from a hydraulic source 68 (see Figure 1) via hydraulic lines 70 (see Figure 1) to the plug member 14 to actuate the lock arrangement 16; apply a test pressure to the seal arrangement 18; and/or disconnect the probe 20 from the plug member 14.

The conduit 58 is isolated by seals 72 disposed in grooves 74 in the probe 20 and is operatively associated with the lock arrangement 16 via communication with the bores 26.

The conduit 60 is operatively associated with the seal arrangement 18 and communicates with the bores 36.

The conduits 62, 64 are operatively associated with the connection arrangement 24.

The conduit 66 is isolated by seals 76 disposed in grooves 78 in the probe 20 and communicates with ports 80 in the manifold 22. Ports 80 are connected to ports 82 in the plug member 14 via conduit 86 (shown in dotted line in Figures 1 and 2) and provide a connection to a locking groove area/region 88 which is bounded by primary seal 44, tertiary seal 50 and the piston seals 32. In use, application of fluid pressure to the region 88 while venting the lock set conduit 58 will provide an unset load to retract the pistons 30 and allow the completion plug 10 to be recovered. The tertiary seal 50 could also be used as a pressure test boundary if either of the primary seal element 38 or secondary seal element 40 are not leak tight. Where this is the case, a sealant may be injected to provide a leak tight primary seal.

In the illustrated embodiment, the manifold 22 is disposed in and connected to the plug member 14 with thread connection 90, as shown in Figure 2.

Flow passages 92 in the manifold 22 are isolated by seals 94 disposed in grooves 96 in the manifold 22 and provide fluid communication with the lock arrangement 16, that is between the conduit 58 in the probe 20 and the bores 26 in the plug member 14.

Flow passage 98 in the manifold 22 provides fluid communication with the seal arrangement 18, that is between the conduit 60 in the probe 20 and the bores 36 in the plug member 14. As shown in Figures 1 and 2, a check valve 100 is disposed in the flow passage 98 to provide fluid communication to the bores 36 but prevent reverse flow when probe 20 is disconnected. Beneficially, the check valve 100 maintains isolation of the bores 36 when the probe 20 is detached from the plug member 14. The check valve 100 is however maintained open while the probe 20 is connected using a spigot 102, thus ensuring pressure can be both applied and vented during the seal tests.

In the illustrated embodiment, the connection arrangement 24 comprises a ball retent sleeve arrangement comprising a sliding sleeve in the form of collet 104 and a plurality of balls 106 (two balls 106 are shown in the cross sectional views shown in

Figures 1 and 2) disposed in a pocket or recess 108 in the manifold 22. As shown most clearly in Figure 2, the collet 104 defines a piston, with fluid supplied via the conduit 62 to a chamber 110 defined between the probe 20 and the collet 104 urging the collet 104 from a first, retaining, position in which the collet 104 retains the balls 106 in the recess 108 to a second, release, position in which the collet 104 no longer retains the balls 106. In this second position, the balls 106 are free to move radially outwards to release the probe 20 from the manifold 22. It will be recognised that the movement of the collet 104 is reversible, by supply of fluid to a second chamber 112 via conduit 64. A deployment arm 114 is used to manipulate the probe 22 during operation, as will be described below.

Operation of the plug assembly 10 will now be described with reference to Figures 3 to 6 of the accompanying drawings.

Referring first to Figure 3 of the accompanying drawings, the plug assembly 10 is initially assembled and secured using the collet 104. The assembled plug 10 is then deployed into flange 12 using a hot tap machine provided with a ported adapter housing or hydraulic deployment launcher (not shown), the plug assembly 10 deployed axially until the primary seal element 38 engages with the flange 12. As shown in Figure 3, the lock arrangement 16 initially defines a retracted configuration (as shown in Figures 1 and 3), in which configuration the dogs 28 initially define a retracted configuration with the dogs 28 disposed in the plug member 14.

When the plug assembly 10 is fully engaged, hydraulic fluid is directed via the conduit 58, the flow passage 92 and bores 26 to urge the pistons 30 and dogs 28 radially outwards into engagement with the flange 12, as shown in Figure 4. The hydraulic volume verifies when full deployment of the dogs 28 has been achieved.

Once fully deployed, the seal arrangement 18 can tested. In the illustrated embodiment, both a rapid initial test and a more rigorous test complying with double block and bleed requirements can be carried out. The initial test involves venting the bores 36 while maintaining launcher and pipeline pressure. While this is quick and sensitive, in order to facilitate a test complying with double block and bleed requirements, the launcher pressure is vented to ambient pressure then pipeline leak test pressure applied to the bores 36 to pressure test the secondary seal element 40 in the correct direction. The bores 36 can then be vented and monitored to verify the integrity of the primary seal element 38; in this way both seal elements 38, 40 are independently verifiable.

Once the seals are verified, the probe 20 can be released and retracted, as shown in Figure 5, and the launcher and temporary valve can be removed and replaced with a blind flange B, as shown in Figure 6. Mounting the lock groove in a sandwich plate - as shown in Figure 6 - allows the completion plug 14 to be retro-fitted to an existing flange.

It should be understood that the embodiment described herein is merely exemplary and that various modifications may be made thereto without departing from the scope of the invention.

For example, while the plug member 14 described above is disc shaped, it will be recognised that the plug member 14 may take a different form. For example, the plug member 14 may alternatively comprise a fabrication having a domed central portion, this having the benefit of reduced weight.

In applications where the ejection load is low enough, the pistons can be used without the dogs, this providing a simplified design. A pressure equalisation port could be added with an additional hydraulic line similar to traditional completion plugs. This could also be protected with a check valve or pilot operated valve. This would simplify the deployment but would require risk assessed against modern isolation standards. This port can however be negated by the application of controlled pressure to the deployment closure.

Activation of the lock arrangement may also take a number of different forms and referring now to Figure 7 of the accompanying drawings, there is shown a completion plug 1010 according to a second embodiment of the invention. The completion plug 1010 is substantially identical to the plug 10 but utilises an alternative activation arrangement to that described above with respect to the first embodiment and like components of the second embodiments to those described in the first embodiment are represented by like numerals incremented by 1000.

As in the plug assembly 10, the plug assembly 1010 comprises a plug member 1014 having a lock arrangement 1016 for use in securing the plug member 1014 to a section of pipe in the form of housing 1012 and a seal arrangement 1018 for sealingly engaging the housing 1012. A probe 1020, which in the illustrated embodiment takes the form of a hydraulic hot stab, is disposed in and coupled to the plug member 1014. In use, the probe 1020 provides fluid communication to the lock arrangement 1016 in order to actuate the lock arrangement 1016, and provides fluid communication to the seal arrangement 1018 to permit seal integrity to be tested.

As in the plug assembly 10, in the plug assembly 1010 the lock arrangement 1016 is disposed in the plug member 1014 and comprises a number of circumferentially arranged shear segments or dogs 1028. Each dog 1028 is coupled to or defines a lock piston 1030. However, in this second embodiment, lock pistons 1030 are held at a locked position with springs 1116 during insertion of the plug member 1014 into housing 1012, hydraulic pressure being applied via ports 1082 and conduit 1086 (in the same manner as described above in the first embodiment with reference to ports 80, ports 82 and conduit 86) which in use form a piston retract circuit, to pull the dogs 1028 inside housing 1012. This second embodiment has the advantage of a mechanical force acting to retain the set dogs 1028, even after the probe 1020 is retracted. Alternative mechanical locks e.g. pins deployed behind the dogs or threaded adaptors can also be utilised, where desired.

As described above, embodiments of the present invention provide dual sealing and a secure restraint without breaching the permanent pressure boundary, while providing a plug assembly in which fluid communication is via the probe permits operation of the plug assembly within a sealed and pressurised environment. Moreover, providing a plug assembly in which fluid communication is via the probe permits the lock arrangement of the plug assembly to be disposed in, and deployed from, the plug member. The pipe section into which the plug assembly is deployed -which in many applications is a permanent fixture - may thus be simpler in construction since no external penetrations are required for the lock arrangement or to facilitate lock actuation, the lack of external penetrations through the pipe section also providing improved pressure integrity, and so eliminating or at least mitigating integrity issues associated with conventional equipment. Providing a plug assembly in which fluid communication is via the probe also permits additional functionality, for example by permitting a pressure test or seal integrity test to be applied to the seal arrangement of the plug assembly.

Claims

1. A plug assembly comprising: a plug member comprising a seal arrangement for sealingly engaging a section of pipe; a lock arrangement for securing the plug member to the section of pipe; and a probe configured to provide fluid communication to the plug member to at least one of: actuate the lock arrangement; apply a test pressure to the seal arrangement; and/or disconnect the probe from the plug member.

2. The plug assembly of claim 1, wherein the plug assembly comprises a completion plug assembly for deployment into the section of pipe and which is operable to isolate the section of pipe.

3. The plug assembly of claim 1 or 2, wherein the plug assembly is fluid actuable.

4. The plug assembly of claim 3, wherein the probe is configured to provide communication of pressurised hydraulic or pneumatic fluid to the plug member.

5. The plug assembly of any preceding claim, wherein a plurality of fluid conduits are formed or provided in the probe to facilitate fluid communication to the plug member.

6. The plug assembly of claim 5, comprising at least one fluid conduit configured to provide fluid communication to the lock arrangement to facilitate activation and/or deactivation of the lock arrangement.

7. The plug assembly of claim 5 or 6, comprising at least one fluid conduit configured to provide fluid communication to the seal arrangement to facilitate a pressure test of the seal arrangement.

8. The plug assembly of claim 5, 6 or 7, comprising at least one fluid conduit configured to provide fluid communication to facilitate disconnection of the probe from the plug member.

9. The plug assembly of any preceding claim, comprising a connection arrangement for connecting the probe to at least one flow line.

10. The plug assembly of claim 9, wherein the connection arrangement comprises at least one port formed in, or disposed in, the probe.

11. The plug assembly of any preceding claim, wherein the plug assembly comprises, or is provided in combination with, at least one flow line.

12. The plug assembly of any preceding claim, wherein the probe comprises a housing, the housing configured for locating the probe into the plug member.

13. The plug assembly of claim 12, wherein the probe comprises or defines at least one of: a male portion for location in a corresponding female portion of the plug member; and a female portion for location on a corresponding male portion of the plug member.

14. The plug assembly of any preceding claim, comprising a coupling arrangement for coupling the probe to the plug member.

15. The plug assembly of claim 14, wherein the coupling arrangement is configured to detachably couple the probe to the plug member.

16. The plug assembly of claim 14 or 15, wherein the coupling arrangement is fluid actuated.

17. The plug assembly of claim 14, 15 or 16, wherein the coupling arrangement comprises a fluid piston.

18. The plug assembly of any one of claims 14 to 17, wherein the coupling arrangement comprisea a collet.

19. The plug assembly of any one of claims 14 to 18, wherein the coupling arrangement comprisea at least one retainer element.

20. The plug assembly of any preceding claim, wherein the plug member comprises at least one flow passage.

21. The plug assembly of claim 20, wherein the plug member comprises at least one flow passage configured to communicate fluid to the lock arrangement.

22. The plug assembly of claim 20 or 21, wherein the plug member comprises at least one flow passage configured to communicate fluid to the seal arrangement.

23. The plug assembly of any preceding claim, wherein the plug member is configured to receive the lock arrangement.

24. The plug assembly of claim 23, wherein the plug member comprise a recess for receiving the lock arrangement.

25. The plug assembly of any preceding claim, comprising a check valve configured to provide selective fluid communication to the seal arrangement.

26. The plug assembly of any preceding claim, comprising a manifold.

27. The plug assembly of claim 26, wherein the manifold is integrally formed with the plug member.

28. The plug assembly of claim 26, wherein the manifold comprises a separate component from the plug member.

29. The plug assembly of any preceding claim, wherein the lock arrangement comprises at least one lock member actuable to engage the pipe section.

30. The plug assembly of any preceding claim, wherein the lock arrangement is fluid actuated.

31. The plug assembly of any preceding claim, wherein the lock arrangement comprises a biasing member configured to retain the lock arrangement in a retracted configuration.

32. The plug assembly of any preceding claim, wherein the lock arrangement comprises at least one fluid piston.

33. The plug assembly of any preceding claim, wherein the seal arrangement comprises at least one seal element disposed on the plug member.

34. The plug assembly of claim 33, wherein the seal arrangement comprises a plurality of seal elements.

35. The plug assembly of claim 34, when dependent on claim 22, wherein the at least one flow passage formed or provided in the plug member to communicate fluid to the seal arrangement is disposed between the seal elements.

36. The plug assembly of claim 33, 34 or 35, wherein at least one seal element of the seal arrangement comprises an elastomeric seal element.

37. The plug assembly of any one of claims 33 to 36, wherein at least one seal element of the seal arrangement comprises a metallic seal element.

38. The plug assembly of any preceding claim, comprising a deployment arm.

39. A method comprising: providing a plug assembly comprising: a plug member comprising a seal arrangement for sealingly engaging the section of pipe; a lock arrangement for securing the plug member to the section of pipe; and a probe configured to provide fluid communication to the plug member; and communicating fluid to the plug member via the probe to at least one of: actuate the lock arrangement; apply a test pressure to the seal arrangement; and/or disconnect the probe from the plug member.

40. A probe for use in the plug assembly of any one of claims 1 to 38.

41. A plug assembly substantially as described herein and/or as shown in the accompanying drawings.

42. A method substantially as described herein and/or as shown in the accompanying drawings.

43. A probe substantially as described herein and/or as shown in the accompanying drawings.