Repairing a wet buckle in a pipeline

1. A method of repairing a length of pipeline which has experienced a wet buckle during deployment from a pipelaying vessel towards a seabed, the method comprising the steps of:

severing the pipeline at locations which are spaced apart on opposite sides of a buckle and removing the buckled section to leave spaced first and second severed ends;

locating a pipeline pig in a pig deployment device;

releasably coupling a pig insertion member of the pig deployment device to the pig;

releasably coupling the pig deployment device to one of the severed ends;

operating the pig deployment device to cause the pig insertion member to translate the pig out of the deployment device and into the pipeline through said severed end;

releasing the pig insertion member from the pig and retracting the pig insertion member, leaving the pig in place within the pipeline;

releasing the pig deployment device from said severed end;

welding the severed ends together; and then

applying fluid pressure to the pig to translate the pig along the pipeline towards an end of the pipeline which is located distally from the vessel, to remove contaminants within the pipeline resulting from the severing process.

2. A method as claimed in claim 1 , in which:

the step of releasably coupling the pig deployment device to said severed end comprises releasably coupling the device to the severed end of the length of pipeline extending from the vessel into the water; and

the step of operating the pig deployment device comprises translating the pig to a location at which at least part of the pig is below a level of water contained within the pipeline.

3. A method as claimed in claim 2 , in which the pig is arranged to provide a wiping seal with a wall of the pipeline, and in which the method comprises expelling air contained between the pig and the surface of water in the pipeline during insertion of the pig.

4. A method as claimed in claim 3 , comprising inserting an elongate breather element into the pipeline adjacent the wall of the pipeline so that, when the pig is inserted into the pipeline, the breather element is located between the wall of the pipeline and the pig to provide a pathway for the passage of air past the pig.

5. A method as claimed in claim 4 , comprising locating the elongate breather element so that it extends along the pipeline from the severed end and into the water in the pipeline.

6. A method as claimed in claim 1 , comprising the further steps of:

deploying the repaired length of pipeline towards the seabed carrying the pig;

arranging the portion of pipeline carrying the pig in a desired deployed position; and then

performing the step of translating the pig along the pipeline.

7. A method as claimed in claim 1 , comprising performing the step of translating the pig along the pipeline, and then:

deploying the repaired length of pipeline towards the seabed carrying the pig; and arranging the portion of pipeline carrying the pig in a desired deployed position.

8. A method as claimed in claim 1 , in which the step of releasably coupling the pig deployment device to one of the severed ends comprises coupling an interface member of the pig deployment device to said end, the interface member being shaped to receive said end.

9. A method as claimed in claim 1 , in which the step of operating the pig deployment device comprises operating a drive arrangement of the device to translate the pig insertion member relative to the pipeline and so insert the pig.

10. A method as claimed in claim 9 , comprising the further steps of:

a) locating the drive arrangement in a starting position;

b) releasably coupling the drive arrangement to the pig insertion member;

c) operating the drive arrangement to move from its starting position towards a finishing position, during which movement the pig insertion member is translated a determined axial distance by the drive arrangement in a direction towards the pipeline;

d) releasing the drive arrangement from the pig insertion member; and

e) returning the drive arrangement to the starting position.

11. A method as claimed in claim 10 , comprising repeating steps b) to e) as necessary in order to locate the pig at a desired position within the pipeline.

12. A method as claimed in claim 9 , comprising releasably coupling the drive arrangement to the pig insertion member using a releasable joint, and releasably coupling the pig insertion member to the pig via a releasable connection.

13. Apparatus for use in repairing a pipeline which has experienced a wet buckle during deployment from a pipelaying vessel towards a seabed, the pipeline having been severed at locations which are spaced apart on opposite sides of the buckle and the buckled section removed to leave spaced first and second severed ends, the apparatus comprising:

a pipeline pig; and

a pig deployment device for inserting the pig into the pipeline, the pig being located in the pig deployment device and the pig deployment device comprising:

a pig insertion member;

a releasable connection by which the pig insertion member is releasably coupled to the pig;

a drive arrangement which is operable to translate the pig insertion member relative to the pipeline and so insert the pig into the pipeline; and

a releasable joint by which the drive arrangement is releasably coupled to the pig insertion member;

in which:

the pig deployment device can be releasably coupled to one of the severed ends and the drive arrangement of the pig deployment device operated to cause the pig insertion member to translate the pig out of the deployment device and into the pipeline through said severed end; and

the releasable connection facilitates subsequent release of the pig insertion member from the pig, so that the pig insertion member can be retracted leaving the pig in place within the pipeline, and the pig deployment device released from said severed end;

so that the severed ends can be welded together and fluid pressure applied to the pig to translate the pig along the pipeline towards an end of the pipeline which is located distally from the vessel, to remove contaminants within the pipeline resulting from the severing process.

14. Apparatus as claimed in claim 13 , in which the pig deployment device comprises a housing defining a pig loading chamber, the pig being translatable from the pig loading chamber into the pipeline.

15. Apparatus as claimed in claim 14 , in which the housing has a bore defining the pig loading chamber, the bore being of a diameter which is greater than a maximum external diameter of the pig.

16. Apparatus as claimed in claim 14 , in which the pig deployment device comprises an interface member which can be coupled to one of the severed ends, and in which the housing is coupled to the interface member.

17. Apparatus as claimed in claim 16 , in which the interface member has a portion which is couplable to said end of the pipeline, and which has a diameter matching an inner diameter of the pipeline.

18. Apparatus as claimed in claim 17 , in which the interface member has a tapered portion which provides a transition from a diameter of the housing bore to the diameter of the portion which is couplable to said end of the pipeline.

19. Apparatus as claimed in claim 16 , in which the interface member defines an abutment surface against which said end of the pipeline can be seated so that the pig deployment device is supported on said end of the pipeline.

20. Apparatus as claimed in claim 13 , in which the drive arrangement is hydraulically operated, comprising at least one piston/cylinder device for controlling movement of the pig insertion member.

21. Apparatus as claimed in claim 20 , in which a piston of the drive arrangement is releasably couplable to the pig insertion member via a connection element.

22. Apparatus as claimed in claim 21 , in which the pig insertion member comprises a plurality of apertures through which a locating pin of the connecting element can be inserted to couple the drive arrangement to the pig insertion member.

23. Apparatus as claimed in claim 13 , in which the releasable connection comprises a bayonet-type fitting having one or more locating pins provided on one of the pig and the pig insertion member, and which mate with a corresponding one or more locating aperture in the other one of the pig and the pig insertion member.

24. Apparatus as claimed in claim 23 , in which the pins and apertures are engaged and disengaged by relative rotary motion between the pig insertion member and the pig.

25. A pipeline pig deployment device comprising:

a housing defining a pig loading chamber of a first diameter;

an interface member coupled to the housing, the interface member adapted to be mounted on an end of a length of pipeline and defining a bore of a second diameter which is smaller than said first diameter and which matches a diameter of a bore of the pipeline;

a pig insertion member;

a releasable connection for releasably coupling the pig insertion member to a pipeline pig;

a drive arrangement for the pig; and

a releasable joint by which the drive arrangement is releasable coupled to the pig insertion member;

in which the drive arrangement of the pig deployment device is operable to translate the pig insertion member relative to the pipeline, to cause the pig insertion member to translate the pig out of the pig loading chamber, through the interface member and into the pipeline through said severed end;

and in which the releasable connection facilitates release of the pig insertion member from the pig so that the pig insertion member can be subsequently retracted leaving the pig in place within the pipeline.

26. A method of repairing a length of pipeline which has experienced a wet buckle during deployment from a pipelaying vessel towards a seabed, the method comprising the steps of:

severing the pipeline at locations which are spaced apart on opposite sides of a buckle and removing the buckled section to leave spaced first and second severed ends, one of said ends being provided on a portion of the pipeline extending from the vessel into the water;

locating a pipeline pig in a pig deployment device;

releasably coupling a pig insertion member of the pig deployment device to the pig;

releasably coupling the pig deployment device to the one of the first and second severed ends provided on the portion of the pipeline extending from the vessel into the water;

operating the pig deployment device to cause the pig insertion member to translate the pig out of the deployment device and into the pipeline through said severed end to a location at which at least part of the pig is below a level of water contained within the pipeline;

arranging the pig so that it provides a wiping seal with a wall of the pipeline and expelling air contained between the pig and the surface of water in the pipeline during insertion of the pig;

releasing the pig insertion member from the pig and retracting the pig insertion member, leaving the pig in place within the pipeline;

releasing the pig deployment device from said severed end;

welding the severed ends together; and then

applying fluid pressure to the pig to translate the pig along the pipeline towards an end of the pipeline which is located distally from the vessel, to remove contaminants within the pipeline resulting from the severing process.

27. A method of repairing a length of pipeline which has experienced a wet buckle during deployment from a pipelaying vessel towards a seabed, the method comprising the steps of:

severing the pipeline at locations which are spaced apart on opposite sides of a buckle and removing the buckled section to leave spaced first and second severed ends;

locating a pipeline pig in a pig deployment device;

releasably coupling a pig insertion member of the pig deployment device to the pig;

releasably coupling the pig deployment device to one of the severed ends;

operating a drive arrangement of the pig deployment device to translate the pig insertion member relative to the pipeline, thereby translating the pig out of the deployment device and into the pipeline through said severed end, in which the step of operating the drive arrangement comprises:

a) locating the drive arrangement in a starting position;

b) releasably coupling the drive arrangement to the pig insertion member;

c) operating the drive arrangement to move from its starting position towards a finishing position, during which movement the pig insertion member is translated a determined axial distance by the drive arrangement in a direction towards the pipeline;

d) releasing the drive arrangement from the pig insertion member; and

e) returning the drive arrangement to the starting position;

releasing the pig insertion member from the pig and retracting the pig insertion member, leaving the pig in place within the pipeline;

releasing the pig deployment device from said severed end;

welding the severed ends together; and then

applying fluid pressure to the pig to translate the pig along the pipeline towards an end of the pipeline which is located distally from the vessel, to remove contaminants within the pipeline resulting from the severing process.

28. A method of repairing a length of pipeline which has experienced a wet buckle during deployment from a pipelaying vessel towards a seabed, the method comprising the steps of:

severing the pipeline at locations which are spaced apart on opposite sides of a buckle and removing the buckled section to leave spaced first and second severed ends;

locating a pipeline pig in a pig deployment device;

releasably coupling a pig insertion member of the pig deployment device to the pig via a releasable connection;

releasably coupling the pig deployment device to one of the severed ends;

releasably coupling a drive arrangement of the pig deployment device to the pig insertion member using a releasable joint;

operating the drive arrangement of the pig deployment device to cause the pig insertion member to translate the pig out of the deployment device and into the pipeline through said severed end;

releasing the pig insertion member from the pig and retracting the pig insertion member, leaving the pig in place within the pipeline;

releasing the pig deployment device from said severed end;

welding the severed ends together; and then

applying fluid pressure to the pig to translate the pig along the pipeline towards an end of the pipeline which is located distally from the vessel, to remove contaminants within the pipeline resulting from the severing process.

29. Apparatus for use in repairing a pipeline which has experienced a wet buckle during deployment from a pipelaying vessel towards a seabed, the pipeline having been severed at locations which are spaced apart on opposite sides of the buckle and the buckled section removed to leave spaced first and second severed ends, the apparatus comprising:

a pipeline pig; and

a pig deployment device for inserting the pig into the pipeline, the pig being located in the pig deployment device and the pig deployment device comprising:

a pig insertion member which is releasably coupled to the pig;

a drive arrangement for translating the pig relative to the pipeline, the drive arrangement being hydraulically operated and comprising at least one piston/cylinder device for controlling movement of the pig insertion member;

in which:

the pig deployment device can be releasably coupled to one of the severed ends and the drive arrangement of the pig deployment device operated to cause the pig insertion member to translate the pig out of the deployment device and into the pipeline through said severed end; and

the pig insertion member can subsequently be released from the pig and retracted leaving the pig in place within the pipeline, and the pig deployment device released from said severed end;

so that the severed ends can be welded together and fluid pressure applied to the pig to translate the pig along the pipeline towards an end of the pipeline which is located distally from the vessel, to remove contaminants within the pipeline resulting from the severing process.

30. Apparatus for use in repairing a pipeline which has experienced a wet buckle during deployment from a pipelaying vessel towards a seabed, the pipeline having been severed at locations which are spaced apart on opposite sides of the buckle and the buckled section removed to leave spaced first and second severed ends, the apparatus comprising:

a pipeline pig; and

a pig deployment device for inserting the pig into the pipeline, the pig being located in the pig deployment device and the pig deployment device comprising a pig insertion member which is releasably coupled to the pig via a releasable connection, the releasable connection comprising a bayonet-type fitting having one or more locating pins provided on one of the pig and the pig insertion member, and which mate with a corresponding one or more locating aperture in the other one of the pig and the pig insertion member;

in which:

the pig deployment device can be releasably coupled to one of the severed ends and the pig deployment device operated to cause the pig insertion member to translate the pig out of the deployment device and into the pipeline through said severed end; and

the pig insertion member can subsequently be released from the pig and retracted leaving the pig in place within the pipeline, and the pig deployment device released from said severed end;

so that the severed ends can be welded together and fluid pressure applied to the pig to translate the pig along the pipeline towards an end of the pipeline which is located distally from the vessel, to remove contaminants within the pipeline resulting from the severing process.