GB2165187A - Module installation and removal - Google Patents

Module installation and removal Download PDF

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Publication number
GB2165187A
GB2165187A GB08514180A GB8514180A GB2165187A GB 2165187 A GB2165187 A GB 2165187A GB 08514180 A GB08514180 A GB 08514180A GB 8514180 A GB8514180 A GB 8514180A GB 2165187 A GB2165187 A GB 2165187A
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GB
United Kingdom
Prior art keywords
module
vessel
support structure
vessels
removal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB08514180A
Other versions
GB8514180D0 (en
Inventor
Marinus Anthonius Wouts
Anton Coppens
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HEEREMA ENGINEERING
Original Assignee
HEEREMA ENGINEERING
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by HEEREMA ENGINEERING filed Critical HEEREMA ENGINEERING
Priority to GB08514180A priority Critical patent/GB2165187A/en
Publication of GB8514180D0 publication Critical patent/GB8514180D0/en
Publication of GB2165187A publication Critical patent/GB2165187A/en
Priority to GB08610370A priority patent/GB2174648B/en
Priority to US06/856,745 priority patent/US4744697A/en
Priority to NO861687A priority patent/NO861687L/en
Priority to NO861689A priority patent/NO861689L/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/003—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for for transporting very large loads, e.g. offshore structure modules
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0039—Methods for placing the offshore structure
    • E02B2017/0047—Methods for placing the offshore structure using a barge
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0052—Removal or dismantling of offshore structures from their offshore location

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Transportation (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Ocean & Marine Engineering (AREA)
  • Jib Cranes (AREA)

Abstract

A module (13) is installed on or removed from a support structure using a vessel (10) with and the module is suspended from the vessel by cranes (18) provided on the vessel while installation or removal is accomplished. The module is suspended from below its centre of gravity. <IMAGE>

Description

SPECIFICATION Module installation and removal This invention relates to a method and apparatus for installing or removing a module on or from a support structure.
This application is supplemental to our earlier Application No. 8510822.
According to the present invention there is provided a method of installing or removing a module on or from a support structure, comprising suspending the module using one or more vessels and bringing the module into or out of engagement with the support structure while the module is being suspended, the module being suspended from below its centre of gravity.
The invention also provides a method of installing or removing a module on or from a support structure using two spaced apart vessels where installation or removal of the module is accomplished while the support structure is located at least partly between the two vessels or below the space between the vessels and the module is being suspended from both vessels.
The invention also provides apparatus for installing or removing a module on or from a support structure comprising at least one vessel, means on the or each vessel for suspending the module while the module is being brought into or out of engagement with the support structure, said means suspending the module from below its centre of gravity.
The invention also provides apparatus for installing or removing a module on or from a support structure comprising two vessels, and means for suspending the module from both vessels, installation or removal of the module taking place while the support structure is at least partly located between or directly below the two vessels and the module is being suspended from both vessels.
By way of example, some embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1,2 and 3 show a vessel installing or removing a module from a support structure; Figure 4 shows the crane system of the vessel in more detail; Figures 5, 6and 7showa pair of vessels installing or removing a module from a support structure; and Figures 8 and 9 show alternative pairs of vessels installing or removing a module from a support structure.
In Figures 1, 2 and 3 there is shown a vessel 10 incorporating two banks of cranes 11, 12 fore and aft of the vessel. The cranes 11, 12 are able to suspend a module 13 over the vessel 10 by means of crane cables 14, which may be chains, lines, ropes etc. The crane cables 14 support the module 13 from below its centre of gravity on a support frame 15. The supportframe 15 may be an integral part of the module 13, as in Figure 1 where the module is an integrated deck, or a separate structure for carrying a module. The cranes 11, 12 need not necessarily have any lifting or lowering capability themselves, and may simply comprise booms 18 from which to hang the module. For reasons that will become clearer later, at least one of the banks of cranes is collapsible.
On the deck of the vessel 10 shown in Figure 1 there are provided blocks 17. These blocks 17 support the module 13 on the deck of the vessel 10 while it is in transit. The module 13 may be initially loaded onto the blocks 17 such as by skidding it from a quay or by deballasting the vessel underneath the module while it rests over the water on suitable supports. The blocks 17 here are in the form of driving wedge arrangements comprising upper and lower taper blocks 19, 20 with a wedge 21 sandwiched in between. The wedges 21 can be withdrawn from between the taper blocks 19,20 by means of hydraulic jacks 22 or other means to reduce the height of the blocks 17 and leave the module 13 suspended from the crane cables 14. Of course, other lowering means could be used.The horizontal position of the module 13 relative to the vessel 10 can be adjusted while the module is being suspended by means of cables 23 and winches 24.
Of course, other means such as by tugger lines or hydraulic jacks could alternatively be used.
As can be seen from Figure 2, the module 13 is wider than the vessel 10 here, so that either end of the module overhangs the vessel, and is to be supported on a pair of spaced apart support structures 25a, 25b. The vessel 10 is able to float in between the two support structures 25a, 25b. There may of course be more than two support structures 25a, 25b. The support structures 25a, 25b have guides 26a, 26b to receive locating pins 27a, 27b on the underneath of the module support frame 15.
Installation of the module 13 is seen taking place in Figure 3. The vessel 10 has been brought into position between the support structures 25a, 25b using mooring lines 28 or other means and anchored by the mooring lines 28. The blocks 17 have been lowered or removed so that the module 13 is now being suspended by the cranes 11, 12. Now, the module 13 is being lowered towards the support structures 25a, 25b so that the locating pins 27a 27b engage the guides 26a 26b. During this operation, there may well be horizontal motions induced in the vessel 10 by action of wind, waves or currents.
Preferably, therefore, the vessel 10 incorporates means for monitoring the horizontal position of the module 13 relative to the support structures 25a, 25b. Such monitoring means may, for example, be by laser. The horizontal position relative to the support structures 25a, 25b ofthe module 13 is preferably adjusted automatically in response to the module position monitor, and this may be done by computer. In the vessel shown in Figures 1,2 and 3, the module horizontal position is adjusted by cables 23 and winches 24, as described above. The lowering of the module 13 onto the support structures 25 may be achieved by ballasting the vessel 10. In this embodiment, however, the module 13 can be lowered by using the cranes 11, 12 instead of or in addition to ballasting the vessel.The cranes 11, 12 comprise main booms 18 attached to pivotal mounts 32, one or which is slidable along rails 16 on the deck of the vessel 10. After installation of the module 13, the bank of cranes 12 is collapsed down onto the deck of the vessel in order that the vessel can be withdrawn from between the support structures 25a, 25b. Removal of the module 13 from the support structures 25a, 25b involves the same operations but of course these are in reverse order. In addition to horizontal position control, there is preferably also means for adjusting the vertical position of the module 13 relative to the vessel 10 in order to be able to compensate for heave motions of the vessels. Naturally, there is preferably also some means to provide synchronous operation of the cranes 11,12 so that the module 13 will remain as level as possible.
From Figure 4, which shows the crane system 11 in more detail, it will be clear that many different crane arrangements are possible. For example, the cranes may have a support member 29 which is tied to the main boom 30 by cable, chain, line or frame structure 31 etc. If one bank of cranes is collapsible, the other cranes may be fixed structures. The crane cables 14 may incorporate hydraulic units or springs so that they have additional elasticity, as may additionally or alternatively member 31. Conventionally, modules have been lifted by lugs or eyes on the top of the module. This means that the module itself will often require strengthening so that it can support its own weight, and it also means that the cranes need long booms. Here, the module is lifted from below its centre of gravity, and only relative short crane booms are necessary.The module is preferably lifted by its support frame.
In Figures 5, 6 and 7 there is shown an alternative installation system where the module 13 is suspended between two separate vessels 50, 51 each with its own bank of cranes 52, 53. The vessels may again be floating bodies, e.g. barges, or semisubmersibles. In this system, the module 13 is loaded onto the cranes 52, 53 of each vessel 50, 51 from a transport vessel 54, which is conveniently a cargo barge. With the vessels 50, 51 anchored apart independently, as shown in Figure 6, the transport vessel 54 carrying the module 13 on blocks 55 is floated between the two vessels.The module 13 is then transferred to the two banks of cranes 52, 53 by ballasting. deballasting either the two vessels 50, 51 and/or the transport vessel 54 and/or by a driving wedge lowering arrangement 56 or other suitable means provided on the transport vessel 54. The module 13 is again advantageously supported by the cranes 52, 53 from below its centre of gravity, at the supportframe 15.
With the module 13 now suspended from the cranes 52, 53 the two vessels 50, 51 are brought into position around the support structure 25 using mooring lines 28 or other suitable means. When the support structure 25 is located between the two vessels 50, 51, as shown in Figure 6, the mooring lines 28 anchor the vessels in this position. The module 13 is now lowered onto the supportstructure 25, as before, with the locating pins 27 engaging in the guides 26. Lowering of the module 13 may be carried out by ballasting the two vessels 50, 51 andlor possibly by use of the cranes 52,53, if these have lifting and lowering power. Removal of a module from a support structure using this system involves the same procedures, but of course these are in reverse order.
In this system, the suspension of the module 13 by the two sets of cranes 52, 53 effectively acts like a mooring for the two vessels 50, 51. The reason for this can be seen from Figure 7 which shows, in simplified terms, what happens if one of the vessels 51 drifts out of position. The cables 57 of cranes 53 are subtending an angle with the vertical, which means that the tension F in the cables has vertical and horizontal components Fv and FH. The horizontal component FH is in a direction tending to restore the vessel 51 to its equilibrium position, where the crane calbes are vertical. It will be appreciated from this that whenever any of the crane cables become inclined to the vertical, there automatically arises a component of force tending to restore the vessels to their equilibrium position in the horizontal plane.
The system therefore acts rather like a mooring, and clearly, the crane structures must be of sufficient strength to be able to withstand such horizontal mooring forces.
The system may have a horizontal position control for the module, with means for horizontal position adjustment, such as by tugger lines or hydraulic jacks, and these may be operated automatically in response to position monitoring means. There may also be means controlling the crane operation so that the module remains as level as possible, and there may be means for adjusting the vertical module position to compensate for heave motions of the vessels.
This system can equally well be used for installing or removing sub-sea modules, such as well heads or templates, on or from support structures which are below the surface of the water, e.g. an installation on the sea bed.
Figures 8 and 9 show two variations of the two vessel system. In Figure 8, one of the vessels 70 is U-shaped, having an opening 71 in which the support structure 25 can be located. The module 13 in this system can be carried by the vessel 70 and there is no need for an additional transport vessel.
One set of cranes 72 is needed on the U-shaped vessel 70 and another set of cranes 73 is needed on the assist vessel 74. During installation or removal, the module 13 is suspended between the two vessels 70, 74 by the two sets of cranes 72,73, just as in the two-vessel system just described. Here, of cause, the U-shaped vessel 70 has first to be brought up into position around the support structure 25, then the assist vessel 74 is brought up, then the module 13 is loaded onto the cranes for lowering into position on the support structure. The removal procedure is the same, but in reverse order. It will be noted that the U-shaped vessel in this system need not be as broad as the vessel shown in our earlier Application No. 8510822 because the cranes here are not located on the sides of the opening. This system can be used as well for the installation or removal of sub-sea modules on or from support structures which are below the surface of the water.
Figure 9 shows a different two-vessel system having a T-shaped vessel 80 which is suitable for use when the support structure is in two or more parts 25a, 25b with a gap in between. The module 13 can be carried on the deck of the T-shaped vessel 80, which means there is no need for a separate transport vessel. Again, the procedure is first to bring the T-shaped vessel 80 up into position in the gap between the support structures 25a, 25b, then bring up the assist vessel 82, and load the module 13 onto the two sets of cranes 83, 84 for lowering into position on the support structures. Again, the removal procedure is the same but in the reverse order. The T-shaped 80 vessel in this system has greater stability than the vessel 10 shown in Figure 3 owing to its shape.

Claims (31)

1. A method of installing or removing a module on or from a support structure, comprising suspending the module using one or more vessels and bringing the module into or out of engagement with the support structure while the module is being suspended, the module being suspended from below its centre of gravity.
2. A method as claimed in Claim 1 comprising suspending the module by a support frame on which the module is carried.
3. A method as claimed in Claim 1 or Claim 2 further comprising adjusting the horizontal position of the module relative to the or each vessel during installation or removal so that its position relative to the support structure remains steady.
4. A method as claimed in Claim 1, Claim 2 or Claim 3 further comprising monitoring the horizontal position of the module relative to the support structure during installation or removal.
5. A method as claimed in claim 4 comprising adjusting the horizontal position of the module in response to monitoring its position relative to the support structure.
6. A method as claimed in any preceding claim further comprising adjusting the vertical position of the module relative to the or each vessel to compensate for heave motions of the vessel.
7. A method as claimed in any preceding claim comprising bringing the module into or out of engagement with the support structure by lowering or lifting the module respectively relative to the support structure.
8. A method as claimed in any preceding claim in which there is one vessel and it has an opening therein in which or directly below which the support structure can be at least partly located, where installation or removal of the module is accomplished while the support structure is at least partly located within or directly below the opening.
9. A method as claimed in any preceding claim wherein the module is a sub-sea module and the support structure is below the surface of the water.
10. A method as claimed in any one of Claims 1 to 7 in which there is one vessel and the support structure has a gap therein which is wide enough for at least part of the vessel, where installation or removal of the module is accomplished while that part of the vessel is at least partly located in said gap.
11. A method as claimed in claim 10 wherein the module is broader than at least part of the vessel so that it overhangs that part of the vessel, and the module is lowered or lifted into or out of engagement with the support structure on either side of that part of the vessel while that part of the vessel is at least partly located in said gap.
12. A method of installing or removing a module on orfrom a support structure using two spaced apart vessels where installation or removal of the module is accomplished while the support structure is located at least partly between the two vessels or below the space between the vessels and the module is being suspended from both vessels.
13. A method as claimed in claim 12 wherein for installation, the two vessels are brought into position around or over the support structure while the module is being suspended from both vessels, and vice versa for removal.
14. A method as claimed in Claim 13 and further comprising a third vessel for transporting the module, where the module is transferred from the third vessel to suspension from the two vessels prior to installation, and vice versa for removal.
15. A method as claimed in Claim 12 wherein one of the vessels is so shaped to be able to support the module in position relative to the support structure, comprising bringing up said one vessel to said position, bringing up said other vessel when the said one vessel is in said position, and suspending the module from both vessels for installation or removal thereof.
16. A method as claimed in Claim 15 wherein said one vessel has an opening therein in which or directly below which the support structure can be at least partly located, the vessel carrying the module over the opening, and being in position when the support structure is at least partly located within or directly below the opening.
17. A method as claimed in any of claims 12to 14 wherein the module is a sub-sea module and the support structure is below the surface of the water.
18. A method as claimed in Claim 15 wherein said one vessel has at least a part thereof which is narrower than the module so that the module overhangs that part of the vessel, and the support structure has a gap therein which is wide enough to receive at least that part of the vessel, the vessel carrying the module with it overhanging that part of the vessel, and being in position when that part of the vessel is at least partly located in said gap.
19. A method as claimed in any of Claims 12 to 18 including suspending the module from below its centre of gravity.
20. A method as claimed in any of Claims 12 to 19 wherein there is means for suspending the module from both vessels, which suspension means acts to restore the relative positions of the vessels if relative movement between the vessels occurs.
21. Apparatus for installing or removing a module on or from a support structure comprising at least one vessel, means on the or each vessel for suspending the module while the module is being brought into or out of engagement with the support structure, said means supporting the module from below its centre of gravity.
22. Apparatus as claimed in Claim 21 wherein there is one vessel and there is an opening in the vessel which allows the vessel to be brought up to the support structure with at least part of the support structure located within or directly below the opening, where installation or removal of the module takes place while the support structure is located at least partly within or directly below said opening.
23. Apparatus as claimed in Claim 21 or Claim 22 wherein the module is a sub-sea module and the support structure is below the surface of the water.
24. Apparatus as claimed in Claim 21 wherein there is one vessel and the support structure has a gap therein which is wide enough for at least part of the vessel to be received therein, where installation or removal of the module takes place while that part of the vessel is at least partly located in said gap.
25. Apparatus as claimed in Claim 24 wherein the module is broader than the vessel, and the module is brought into engagement with the support structure on either side of that part of the vessel while that part of the vessel is at least partly located in said gap.
26. Apparatus for installing or removing a module on or from a support structure comprising two vessels, and means for suspending the module from both vessels, installation or removal of the module taking place while the support structure is at least partly located between or directly below the two vessels and the module is being suspended from both vessels.
27. Apparatus as claimed in Claim 26 wherein the means for suspending the module is able to act to restore the relative position of the vessels if relative movement between the vessels occurs.
28. Apparatus as claimed in Claim 26 or Claim 27 wherein the suspending means suspends the module from below its centre of gravity.
29. Apparatus as claimed in any of Claims 26 to 28 wherein the module is a sub-sea module and the support structure is below the surface of the water.
30. A method substantially as hereinbefore described with reference to the accompanying drawings.
31. Apparatus substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
GB08514180A 1985-04-29 1985-06-05 Module installation and removal Withdrawn GB2165187A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB08514180A GB2165187A (en) 1985-06-05 1985-06-05 Module installation and removal
GB08610370A GB2174648B (en) 1985-04-29 1986-04-28 Installation and removal vessel
US06/856,745 US4744697A (en) 1985-04-29 1986-04-28 Installation and removal vessel
NO861687A NO861687L (en) 1985-04-29 1986-04-29 FARTOEY.
NO861689A NO861689L (en) 1985-04-29 1986-04-29 MODULE INSTALLATION AND REMOVAL SYSTEM.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08514180A GB2165187A (en) 1985-06-05 1985-06-05 Module installation and removal

Publications (2)

Publication Number Publication Date
GB8514180D0 GB8514180D0 (en) 1985-07-10
GB2165187A true GB2165187A (en) 1986-04-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB08514180A Withdrawn GB2165187A (en) 1985-04-29 1985-06-05 Module installation and removal

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100186651A1 (en) * 2009-01-26 2010-07-29 Technip France Preloading to reduce loads and save steel on topsides and grillage of catamaran systems

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1466279A (en) * 1973-07-05 1977-03-02 Akers Mek Verksted As Deck structure and method for building same
GB2010947A (en) * 1977-12-19 1979-07-04 Cie Generale Pour Les Developp Method and apparatus for the working of underwater deposits
GB2064628A (en) * 1978-04-03 1981-06-17 Brown & Root Method of and apparatus for erecting an offshore structure
GB2084228A (en) * 1980-08-20 1982-04-07 Duke Jonathan Adam Mine lifting apparatus
GB2119322A (en) * 1981-11-24 1983-11-16 Hitachi Shipbuilding Eng Co Work ship for installing large offshore structures
GB2120607A (en) * 1981-11-25 1983-12-07 Hitachi Shipbuilding Eng Co Work ship for installing large offshore structure

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1466279A (en) * 1973-07-05 1977-03-02 Akers Mek Verksted As Deck structure and method for building same
GB2010947A (en) * 1977-12-19 1979-07-04 Cie Generale Pour Les Developp Method and apparatus for the working of underwater deposits
GB2064628A (en) * 1978-04-03 1981-06-17 Brown & Root Method of and apparatus for erecting an offshore structure
GB2084228A (en) * 1980-08-20 1982-04-07 Duke Jonathan Adam Mine lifting apparatus
GB2119322A (en) * 1981-11-24 1983-11-16 Hitachi Shipbuilding Eng Co Work ship for installing large offshore structures
GB2120607A (en) * 1981-11-25 1983-12-07 Hitachi Shipbuilding Eng Co Work ship for installing large offshore structure

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100186651A1 (en) * 2009-01-26 2010-07-29 Technip France Preloading to reduce loads and save steel on topsides and grillage of catamaran systems
US8312828B2 (en) * 2009-01-26 2012-11-20 Technip France Preloading to reduce loads and save steel on topsides and grillage of catamaran systems

Also Published As

Publication number Publication date
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