System and method for abandoning and recovering pipeline
First Claim
1. A method of abandoning a pipeline being J-laid by a vessel, wherein a sealine comprising the pipeline is initially held by a pipe laying and tensioning arrangement, the method including the steps of reducing the tension at sea level of the sealine, and thereafter lowering the end of the sealine towards the seabed using a line from a winch on the vessel, thereby enabling the maximum load bearing capacity of the winch to be substantially less than the maximum load bearing capacity of the pipe laying and tensioning arrangement.
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Accused Products
Abstract
A method of abandoning a pipeline (2) being laid by a vessel having an A/R system, wherein a sealine (2, 11, 13) is initially held by a pipe laying and tensioning arrangement. The method includes a step of reducing tension at sea level of the sealine (2, 11, 13), by connecting one or more buoyant members (13) to the end of the pipeline (2). The members (13) are then lowered into the sea, using a line (16). At least one member (13) is connected to the pipeline (2) through a connection (12) which allows pivoting of the member (13) so that the end of the member (13) at the end of the pipeline (2) projects upwardly from the seabed (3).
50 Citations
45 Claims
- 1. A method of abandoning a pipeline being J-laid by a vessel, wherein a sealine comprising the pipeline is initially held by a pipe laying and tensioning arrangement, the method including the steps of reducing the tension at sea level of the sealine, and thereafter lowering the end of the sealine towards the seabed using a line from a winch on the vessel, thereby enabling the maximum load bearing capacity of the winch to be substantially less than the maximum load bearing capacity of the pipe laying and tensioning arrangement.
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24. A method of abandoning a pipeline being laid by a vessel, including the steps of connecting one or more buoyant elongate members to the end of the pipeline, thereafter lowering the elongate members into the sea and then abandoning the pipeline, wherein one or more elongate members are so connected to the pipeline that the end of the elongate member at the end of the pipeline projects upwardly from the seabed, thereby facilitating the future recovery of the pipeline.
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25. A method for disconnecting a winch line from a pipeline, the method including the steps of:
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connecting a first part of a connector to the pipeline, providing a second part of the connector on the winch line, the first and second parts being able to mate with one another and being provided with a locking/unlocking arrangement that can be remotely actuated, mating the first and second parts of the connector and locking them together, and when the first and second parts of the connector are underwater, remotely actuating the locking/unlocking arrangement to unlock the parts and thereafter disconnecting the parts.
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26. A disconnection system for disconnecting a winch line from a pipeline, the system comprising:
- first and second parts of a connector and a locking mechanism, wherein the first part is connectable to a pipeline, the second part is connectable to a winch line, the first and second parts are able to be connected and locked together by the locking mechanism, and the first and second parts are able to be unlocked when underwater by remote actuation of the locking mechanism.
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27. A pipe laying vessel including a pipe laying and tensioning arrangement for withstanding the tension exerted by a pipeline during laying of the pipeline and an A/R system comprising an A/R winch and line, the winch and line being suitable for use when abandoning a pipeline during laying, and one or more light elongate members, wherein the light elongate members are configured for connecting to a pipeline for the purpose of reducing the tension at sea level of a sealine comprising or consisting of the pipeline, and the safe working load of the winch is lower than the safe working load of the pipe laying and tensioning arrangement.
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28. A method of abandoning a pipeline being laid by a vessel, wherein a sealine comprising the pipeline is initially held by a pipe laying and tensioning arrangement used for laying the pipeline, the tension at sea level of the sealine being at a first level, the method including the steps of
(i) connecting one or more buoyant elongate members to the end of the pipeline, (ii) using the pipe laying and tensioning arrangement to lower the elongate members into the sea, thereby reducing the tension at sea level of the sealine, (iii) thereafter holding the sealine with the pipe laying and tensioning arrangement with the tension at sea level of the sealine being at a second level substantially lower than the first level, (iv) thereafter lowering the end of the sealine towards the seabed using a line from a winch on the vessel, and (v) thereafter disconnecting the sealine from the winch line wherein the maximum load bearing capacity of the winch is substantially less than the maximum load bearing capacity of the pipe laying and tensioning arrangement.
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29. A method of abandoning a pipeline being laid by a vessel, wherein a sealine comprising the pipeline is initially held by a pipe laying and tensioning arrangement, the method including the steps of
(i) reducing the tension at sea level of the sealine by (a) connecting one or more buoyant members to the end of the pipeline, (b) connecting an intermediate elongate member between the end of the pipeline and a buoyant elongate member, and (c) lowering the elongate members into the sea, (ii) thereafter lowering the end of the sealine towards the seabed using a line from a winch on the vessel, the method thereby enabling the maximum load bearing capacity of the winch to be substantially less than the maximum load bearing capacity of the pipe laying and tensioning arrangement.
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30. An A/R system including a winch and line and one or more light elongate members, wherein the A/R system is adapted for carrying out a method of abandoning a pipeline on a vessel having a pipe laying and tensioning arrangement, and the one or more light elongate members are so shaped and configured (i) to be connectable to the end of the pipeline held by the pipe laying and tensioning arrangement to form a sealine, and (ii) to be able to be lowered into the sea by the pipe laying and tensioning arrangement, so that the tension at sea level of the sealine may be reduced before connecting the line of the winch to the pipeline via the one or more light elongate members,
whereby the maximum load bearing capacity of the winch may be substantially less than the maximum load bearing capacity of the pipe laying and tensioning arrangement.
- 31. An A/R system including a winch and line, one or more buoyant elongate members and an intermediate elongate member, wherein the A/R system is arranged to be suitable for carrying out a method of abandoning a pipeline on a vessel having a pipe laying and tensioning arrangement for laying and holding a pipeline, the one or more buoyant elongate members are so shaped and configured to be connectable between the end of the pipeline and a buoyant elongate member, the intermediate elongate member is so shaped and configured to be connectable to the end of a sealine comprising the pipeline, and the elongate members are so shaped and configured to be able to be lowered into the sea by the pipe laying and tensioning arrangement, so that the tension at sea level of the sealine may be reduced before connecting the line of the winch to the pipeline via the one or more elongate members, whereby the maximum load bearing capacity of the winch may be substantially less than the maximum load bearing capacity of the pipe laying and tensioning arrangement.
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32. An A/R system including a winch and line and one or more light elongate members, wherein the A/R system is arranged to be suitable for carrying out a method of abandoning a pipeline on a vessel, and the one or more light elongate members are so shaped and configured to be connectable to the end of the pipeline so that after abandonment of the pipeline the end of the elongate member at the end of the pipeline projects upwardly from the seabed, thereby facilitating the future recovery of the pipeline.
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33. An A/R system including a winch and line and at least one buoyant elongate member, wherein the A/R system is arranged to be suitable for carrying out a method of abandoning a pipeline on a vessel, and the buoyant elongate member includes a pivot joint that facilitates pivoting movement of the end of the buoyant elongate member about a position at or near the end of a sealine comprising the pipeline, the buoyant elongate member being buoyant enough that after abandonment of the pipeline the end of the elongate member at the end of the pipeline projects upwardly from the seabed, thereby facilitating the future recovery of the pipeline.
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42. A pipe laying vessel including a pipe laying and tensioning arrangement for withstanding the tension exerted by a pipeline during laying of the pipeline and an A/R system comprising an A/R winch and line, the winch and line being suitable for use when abandoning a pipeline during laying, and one or more buoyant elongate members, wherein
the buoyant elongate members are configured for connecting to the end of a pipeline for the purpose of reducing the tension at sea level of a sealine comprising the pipeline, the one or more buoyant elongate members and pipe laying and tensioning arrangement are so shaped and configured that the pipe laying and tensioning arrangement can hold and lower the sealine by holding a buoyant elongate member at the end of the sealine, and the maximum load bearing capacity of the winch is substantially less than the maximum load bearing capacity of the pipe laying and tensioning arrangement.
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44. A disconnection system for disconnecting a winch line from a pipeline, the system comprising:
- a first part of a connector, the first part being connectable to a pipeline; and
a second part of the connector, the second part being connectable to a winch line;
the first and second parts being able to be connected and locked together by a locking mechanism and being able to be unlocked when underwater by remote actuation of the locking mechanism, wherein the system is so arranged that upon unlocking, the first part of the connector remains attached to the pipeline and the second part of the connector attached to the winch line.
- a first part of a connector, the first part being connectable to a pipeline; and
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45. A method of abandoning a pipeline being laid by a vessel, wherein a sealine comprising the pipeline is initially held by a pipe laying and tensioning arrangement, the tension at sea level of the sealine being at a first level, the method including the steps of:
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(i) reducing the tension at sea level of the sealine, (ii) thereafter holding the sealine with the pipe laying and tensioning arrangement with the tension at sea level of the sealine being at a second level substantially lower than the first level, and (iii) thereafter lowering the end of the sealine towards the seabed using a line from a winch on the vessel, whereby the maximum load bearing capacity of the winch is able to be substantially less than the maximum load bearing capacity of the pipe laying and tensioning arrangement.
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Specification