EP0249422A1 - Méthode et dispositif pour soulever des plateformes semi-sumersibles - Google Patents

Méthode et dispositif pour soulever des plateformes semi-sumersibles Download PDF

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Publication number
EP0249422A1
EP0249422A1 EP87305033A EP87305033A EP0249422A1 EP 0249422 A1 EP0249422 A1 EP 0249422A1 EP 87305033 A EP87305033 A EP 87305033A EP 87305033 A EP87305033 A EP 87305033A EP 0249422 A1 EP0249422 A1 EP 0249422A1
Authority
EP
European Patent Office
Prior art keywords
barge
barges
rig
floating body
floating
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Withdrawn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
EP87305033A
Other languages
German (de)
English (en)
Inventor
Fredrik Waage-Rasmussen
Per Johansson
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.)
NEPTUN MARINE CONTRACTING AS
HAUGESUND MEKANISKE VERKSTED AS
Original Assignee
NEPTUN MARINE CONTRACTING AS
HAUGESUND MEKANISKE VERKSTED AS
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 NEPTUN MARINE CONTRACTING AS, HAUGESUND MEKANISKE VERKSTED AS filed Critical NEPTUN MARINE CONTRACTING AS
Publication of EP0249422A1 publication Critical patent/EP0249422A1/fr
Withdrawn legal-status Critical Current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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63C—LAUNCHING, HAULING-OUT, OR DRY-DOCKING OF VESSELS; LIFE-SAVING IN WATER; EQUIPMENT FOR DWELLING OR WORKING UNDER WATER; MEANS FOR SALVAGING OR SEARCHING FOR UNDERWATER OBJECTS
    • B63C1/00—Dry-docking of vessels or flying-boats
    • B63C1/02—Floating docks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63C—LAUNCHING, HAULING-OUT, OR DRY-DOCKING OF VESSELS; LIFE-SAVING IN WATER; EQUIPMENT FOR DWELLING OR WORKING UNDER WATER; MEANS FOR SALVAGING OR SEARCHING FOR UNDERWATER OBJECTS
    • B63C1/00—Dry-docking of vessels or flying-boats
    • B63C1/12—Docks adapted for special vessels, e.g. submarines

Definitions

  • the present invention relates to a method and an arrangement for raising or docking semi-submersible or partly submersible rigs which are supported in water by pontoons or the like on their lower parts.
  • rigs Semi-submersible drilling rigs, accommodation platforms, service rigs, crane barges, or the like (all to be included in the term "rigs" used hereinafter) are built especially with a view to being able to carry out necessary maintenance operations without docking the rig.
  • Ship register companies do not require docking of rigs, in contrast to what is required for ships, and necessary underwater jobs on e.g. pontoons may nowadays be carried out by various methods dependent on the kind of maintenance task. Diving is much used, e.g. when anodes, etc. are to be replaced. When welding operations are necessary a water-evacuated habitat is often used. During mounting operations of shafts the rig may commonly need to be trimmed and/or heeled. Dry docking is another possibility, but in Europe this is at present only possible at a limited number of docks especially built for large tankers.
  • the invention seeks to solve these problems by providing one or more - commonly two - ballastable barges moored so as to be mutually stationary in the longitudinal and transversal direction, also being moored to a ballastable buoyancy body capable of great variations in draught, e.g. a floating dock, or another barge.
  • the relative positions of the barges are adapted to the design and location of rig supporting portions e.g. pontoons, on the rig to be raised.
  • the sterns of the barges are ballasted to sink them to a desired depth; then the bows of the barges and the buoyancy body are ballasted simultaneously so that they sink to a desired depth, but so that part of the buoyancy body always remains above the water surface.
  • the rig is then positioned above the barge or barges, and preferably moored so as to be stationary in the longitudinal as well as the transverse direction, after which the buoyancy body and barge or barges are then raised by de-ballasting them until contact is achieved between rig and barge.
  • each barge is de-ballasted so that it rises bow first to bring the front part of the barge into contact with the rig, after which the stern of each barge is raised with its position controlled until there is contact between rig and barges along the entire length of the rig.
  • the buoyancy body and the barge(s) are further de-ballasted to raise the rig to a desired level, the stability being maintained.
  • the barges with the rig on board may be released from the floating body e.g. dock and move to e.g. a fixed dock, quay, or the like.
  • each barge may if desired be moored with its stern rather than its bow towards the buoyancy body.
  • Stationary barge mooring in the longitudinal and transversal directions, as well as in the vertical direction at the end attached to the buoyancy body may be achieved by having each barge provided at that end with one or a number of connections in the form of wires, chains, or the like which are secured to the barge and to the buoyancy body, and which are in tension throughout the ballasting and de-ballasting operation.
  • the other end is accordingly moored by one or a number of connections extending on either side of the barge, each connection forming an angle with the longitudinal axis of the barge being anchored to e.g.
  • connections may, advantageously, be provided with load cells for monitoring loads at the connection(s).
  • Preferably floating bodies or stabilizing members are provided toward the barge's stern at each side, and are connected with the barge by chains, wires, or the like of a length that is adapted to the desired depth of the barge at the time that the rig is to be positioned over it. These bodies or members will function to stabilise the barge when their connections to the barge come into tension.
  • each barge (and the rig) is preferably trimmed to a longitudinal inclination between 0° and 5° relative to the horizontal, preferably 2°, before the area of contact between the bottom of the rig and the deck of the barge intersects the water line. This helps to ensure further enhancement of stability in this phase.
  • the barges are moored mutually substantially parallel, and substantially normal to that longitudinal side of the buoyancy body to which they are moored.
  • the invention also provides an arrangement for carrying out the above method, comprising at least one barge moored to a buoyancy body so as to be articulated thereto in the manner described above.
  • the stability and level of submerged barges is commonly controlled by one or more of the following methods:
  • the buoyancy body ensures the location of the barges in the longitudinal and transverse directions, while the draught and relative vertical alignment of the barges are controlled at the transversal end connected with the buoyancy body.
  • the barges When the barges are submerged their draught may be varied without ballasting or de-ballasting them by varying the draught of the buoyancy body. Mooring of the barge and rig unit is simplified if the buoyancy body has an anchoring/mooring system of its own which is able to absorb great forces.
  • FIG. 1 is a diagrammatical view of a floating dock 6 which is in connection with two barges 5.
  • Floating dock 6 has a large displacement and offers the possibility of great variations of draught, e.g. through 10 meters.
  • the two barges 5 are suitably arranged at about 90° to one long side of floating dock 6.
  • the distance between the barges is adapted to the distance between pontoons 3 on a rig 2 which is to be raised.
  • One transversal end of the barges, the bow or stern is in direct contact with the floating dock 6 by a fender 16.
  • One of the barges 5 facing the floating dock is moored by one or a number of connections 7 in the shape of wires, chains, or the like.
  • connections 7 extend from each side or each corner of the barge, and approximately horizontally towards the floating dock. These connections are tensioned to always provide a positive force from barge 5 toward fender 16 and, thus, to ensure a continuous contact between the barge and fender 16 or the floating dock. End 12 of barge 5 facing the floating dock is furthermore moored by a connection 13 between a centrally located anchoring point 17 on barge 5 and an anchoring point 18 at a higher level on floating dock 6. Barge 5 is de-ballasted to have a substantial load absorbed by connection 13 ensuring tension of said connection during the entire operation. This connection should be provided with a load cell 10 for monitoring the load.
  • Figure 1 also shows moorings 8 in the shape of wires, chains, or the like for the barge 5 facing away from floating dock 6. These moorings are attached at each side of the barge and at a quay 20, a buoyancy body 6, a point on shore or on the bottom of the sea, or at the other barge. Being moored and connected to the floating dock in this manner the barges cannot make any surging, heaving or swaying movement relative to the floating dock. They may, however make a slight rolling movement and a pitching movement, although the last mentioned is not about a midships axis but at the end facing the floating dock, about an axis parallel with the floating dock and the water surface. In this manner an articulated connection is provided between barges 5 and floating dock 6.
  • Figure 1 also shows a number of floating bodies 1 or stabilizing members which are in connection with the barge's sides at the end facing away from the floating dock.
  • Members 1 are connected with barges 5 via chains, wires, or the like of a desired length which is adapted to the desired draught to which the barges must be lowered before the rig can be floated on top of them.
  • barges 5 When having the rig float to over the barges a free space between pontoons and barges is calculated to 0.5 m - 1.0 m. Commonly the barges must be lowered 6.5 - 8.5 m below the water line 4.
  • Figures 2 - 5 show the immersing operation of a barge 5.
  • barges 5 are moored at one transversal end, hereinafter called the bow, to floating dock 6.
  • the other transversal end hereinafter called the stern
  • Stabilizing members 1 remain on the water surface, and the stern of the barge is ballasted until the connections between stabilizing members 1 and the stern 11 are tensioned, as shown in Figure 4.
  • the stability of the barge is ensured. Stability during the immersion of the stern is also ensured, part of the barge all the time being kept above water and a waterline area thus being maintained.
  • ballasting of the bow 12 and floating dock 6 is initiated simultaneously and in such a manner as to maintain the tension of the connection 13. Ballasting of the barges stops when they are immersed below the water surface. Immersion of the correct draught is then achieved just by varying the draught of the floating dock. Part of floating dock 6 must always be maintained above the water surface 4 in order to maintain stability of the barges and the floating dock, as shown in Figure 5.
  • Figure 6 shows how barges 5 are moored to floating dock 6, and to the bottom of the sea, and to a point on shore or on a quay 20, to hold them in a fixed position.
  • Figure 7 shows the floating dock and the barges in an immersed state.
  • Figures 8 - 11 show how a raising operation of a rig is carried out.
  • a rig 2 is floated onto barges 5 and correctly positioned relative to the barges.
  • the mutual distance between barges 5 is adapted to the distance between pontoons 3 of the rig.
  • the first phase of the raising operation may be carried out in two different manners.
  • One manner comprises first de-ballasting the floating dock and the bow of the barge to achieve contact between the forepart of the barges and rig pontoons 3, and then de-ballasting and raising the after body of the barges under position control, until contact is achieved between the rig and the barges all over the length of the rig.
  • Another method for carrying out this phase is to make connections between the stabilizing means and the after end of the barges slightly shorter, and to ballast the barges additionally, ballasting the floating means if desired, in order to achieve the same draught of the stern as mentioned above.
  • de-ballasting of the barge's forward parts, after parts, and of the floating dock may be carried out in parallel to achieve contact between barges 5 and rig 2 approximately at the same time all along the length of rig 2.
  • the barges (and the rig) are advantageously trimmed some degrees in the longitudinal direction, preferably 1 - 2°, before the bottom of the rig and barge deck intersect the water line, in order to ensure stability additionally in this phase. This is indicated in Figure 10.
  • Figure 11 shows the rig in its final raised position. It may now, if desired, be released from the floating dock and be moved to a fixed dock, to a quay, or to another place.
  • Figure 12 shows floating dock 6, barges 5, and a rig 2 raised out of the water by the aid of the barges and the floating dock.
  • Figure 13 shows the connection between barges 5 and floating dock 6 in more detail.
  • a fender 16 as mentioned, is provided between the floating dock and the barge, and when the barge is moored to the floating dock as described above, an articulated connection 9 is formed between barges 5 and floating dock 6.
  • An auxiliary fender 21 is also indicated between pontoon 3 and the floating dock.
  • the distance between point of attachment 17 on the barge and point of attachment 18 on the floating dock is preferably such that the connection 13 effectively transfers vertical forces.
  • a suitable vertical distance will be approximately 10 meters.
  • Figure 13 shows the barges and the floating dock in an immersed state with a rig positioned on top of the barges.
  • the barges are suitably provided with keel pads 22 for rest against rig pontoons 3.
  • the keel pads 22 are suitably of such a height and have such mutual distance that operators are able to do work on the underside of pontoons 3.
  • stabilizing means 1 that are connected to the barge sides were mentioned above, it is also possible to ground the barges, if desired lowering them with the aid of floating cranes, jacks between the stern of the barge and the bottom, or with turrets on the barges intersecting the water surface to provide additional stability.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Transportation (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Paper (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
  • Treating Waste Gases (AREA)
  • Ship Loading And Unloading (AREA)
  • Underground Structures, Protecting, Testing And Restoring Foundations (AREA)
EP87305033A 1986-06-09 1987-06-08 Méthode et dispositif pour soulever des plateformes semi-sumersibles Withdrawn EP0249422A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO862299A NO159006C (no) 1986-06-09 1986-06-09 Fremgangsmaate og anordning til heving eller dokksetting av halvt nedsenkbare rigger.
NO862299 1986-06-09

Publications (1)

Publication Number Publication Date
EP0249422A1 true EP0249422A1 (fr) 1987-12-16

Family

ID=19888977

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87305033A Withdrawn EP0249422A1 (fr) 1986-06-09 1987-06-08 Méthode et dispositif pour soulever des plateformes semi-sumersibles

Country Status (5)

Country Link
EP (1) EP0249422A1 (fr)
DK (1) DK278887A (fr)
FI (1) FI872565A (fr)
NO (1) NO159006C (fr)
PT (1) PT85040A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2306138A (en) * 1995-10-11 1997-04-30 Kvaerner Oil & Gas Ltd Method of assembling a floating platform
GB2315464A (en) * 1996-07-23 1998-02-04 John Gibson Agencies Ltd Transporting offshore structures
KR20150127400A (ko) * 2014-05-07 2015-11-17 대우조선해양 주식회사 바지선과 부유식 도크를 연결하는 도킹 기기 및 상기 도킹 기기를 이용하여 바지선과 부유식 도크를 연결하는 방법
CN107187554A (zh) * 2017-05-17 2017-09-22 中国海洋石油总公司 用于半潜式钻井平台干拖运输的双体半潜驳船及作业方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR377408A (fr) * 1907-03-16 1907-09-06 William Thomas Donnelly Cale sèche flottante
FR2260493A1 (en) * 1974-02-13 1975-09-05 Emh Dock system for sea platform servicing - has several docks mounted under the platform floats
GB1454113A (en) * 1973-07-10 1976-10-27 Fayren J M Floating vessels for handling large items
GB1502417A (en) * 1975-02-17 1978-03-01 Sea & Land Pipelines Vessels for use in the construction of rigs or other structures in a body of water
GB2153748A (en) * 1984-02-09 1985-08-29 John Wright Servicing of oil rigs

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR377408A (fr) * 1907-03-16 1907-09-06 William Thomas Donnelly Cale sèche flottante
GB1454113A (en) * 1973-07-10 1976-10-27 Fayren J M Floating vessels for handling large items
FR2260493A1 (en) * 1974-02-13 1975-09-05 Emh Dock system for sea platform servicing - has several docks mounted under the platform floats
GB1502417A (en) * 1975-02-17 1978-03-01 Sea & Land Pipelines Vessels for use in the construction of rigs or other structures in a body of water
GB2153748A (en) * 1984-02-09 1985-08-29 John Wright Servicing of oil rigs

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2306138A (en) * 1995-10-11 1997-04-30 Kvaerner Oil & Gas Ltd Method of assembling a floating platform
GB2306138B (en) * 1995-10-11 1999-10-27 Kvaerner Oil & Gas Ltd Method of assembly for buoyant platform
GB2315464A (en) * 1996-07-23 1998-02-04 John Gibson Agencies Ltd Transporting offshore structures
KR20150127400A (ko) * 2014-05-07 2015-11-17 대우조선해양 주식회사 바지선과 부유식 도크를 연결하는 도킹 기기 및 상기 도킹 기기를 이용하여 바지선과 부유식 도크를 연결하는 방법
CN107187554A (zh) * 2017-05-17 2017-09-22 中国海洋石油总公司 用于半潜式钻井平台干拖运输的双体半潜驳船及作业方法

Also Published As

Publication number Publication date
FI872565A0 (fi) 1987-06-08
DK278887A (da) 1987-12-10
NO159006C (no) 1988-11-23
NO159006B (no) 1988-08-15
NO862299L (no) 1987-12-10
FI872565A (fi) 1987-12-10
PT85040A (pt) 1988-07-01
DK278887D0 (da) 1987-06-01
NO862299D0 (no) 1986-06-09

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Inventor name: WAAGE-RASMUSSEN, FREDRIK