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
  • B63B35/03—Pipe-laying vessels
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L1/00—Laying or reclaiming pipes; Repairing or joining pipes on or under water
  • F16L1/12—Laying or reclaiming pipes on or under water
  • F16L1/20—Accessories therefor, e.g. floats, weights
  • F16L1/202—Accessories therefor, e.g. floats, weights fixed on or to vessels
  • F16L1/203—Accessories therefor, e.g. floats, weights fixed on or to vessels the pipes being wound spirally prior to laying
• • 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
  • 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
  • B63B35/66—Tugs

Definitions

• a method and a vessel for pipe-laying at sea are disclosed.
• the present invention relates to a method for laying a pipeline, umbilical or other coilable device from a lay- barge at sea, where the pipeline is uncoiled from a pipe 5 coil arranged on the barge and is guided therefrom via a ramp at one side of the barge down to the sea floor while the lay-barge is moved along a predetermined track.
• a lay-barge for such a purpose is disclosed in GB 1312592.
• the barge is supposed to be o moved along the laying track by means of tug boats .
• three or four tug boats may be needed, for instance as shown in US 4117692.
• it will be difficult to coordinate the pulling di- 5 rection and force in order to facilitate the necessary control of the tension of the pipe and its angle with respect to the bottom of the sea during the laying. This is very important in order for the pipe not becoming over- stressed and damaged.
• Figure 1 shows a plan view of a first vessel according to o the invention comprising a barge and a dynamically posi- tionable vessel arranged side by side,
• Figure 2 shows a side view of the barge of Figure 1
• Figure 3 shows an end view at a larger scale of the composite vessel of Figure 1 without deck equipment
• FIG. 4 shows a side view of a composite vessel comprising a barge and a dynamically positionable heavy lift vessel
• Figure 5 shows a plan view of the vessel of Figure 4.
• the vessel shown in Figure 1 comprises a barge 1, for in- 0 stance a standard North Sea barge having a flat deck and dimensions of 90 x 27 metres.
• the barge is connected to a dynamically positionable (DP) vessel 2 by means of moorings 17.
• the DP-vessel is preferably of consequence class 2.
• the barge 1 is provided with a forward carousel or reel 3 with a coiled pipe 8.
• a pipe deflector 10 When uncoiling the pipe during laying the pipe passes from the reel 3 via a pipe deflector 10 to a pipe straightener 7, and from there on to a forward and a rear pipe tensioner 5 and 6, respectively.
• the o pipe further passes over a pivotally supported pipe ramp 9, which may be raised and lowered by means of a crane 11.
• the barge has a rear reel 4 for pipe or umbilical .
• the barge On the deck between the reels 3 and 4 the barge is pro- vided with a power station 13, a control room 14, a crew room 15 and a workshop 16. In conjunction with the forward reel 3 a moveable winch 18 is arranged. A crane 19 having a capacity of 10-20 tons and good lifting heights is placed so that it can handle the pipe ends during coiling of a pipe. For this operation the barge also has a welding station and a station for non-distractive testing, and a gripping arrangement for fixation of the pipe for welding (not shown) . An A/R (abandonment/recovery) winch is designated 12.
• the barge 1 alone is shown in side view in Figure 2.
• the reels 3 , 4 of the barge are loaded with pipe or umbilical at land-based fabrication facility.
• the unmanned barge is towed to the installation site, e.g. by means of a standard tug boat, typically hav- ing 60-80 tons BP.
• the barge 1 is coupled to the DP vessel 2.
• This may be an anchor handling vessel (AHV) of DP class 2.
• the AHV is moored along the barge using its usual mooring equipment, i.e. hawsers 17, with necessary fenders 20 therebetween.
• the hull model in the software of the DP system must be changed, i.e. a new geometry and new coefficients for s wing, current and waves must be introduced. This is an operation which can be performed easily for most DP systems in current use. When this is done, a common DP test must be performed before the laying operation starts. In order to have control of where the pipe is laid on the sea o floor, an ROV must be used for monitoring of "touchdown” . It would be natural and most economical to place the ROV on the AHV. Furthermore, an acoustic reference system may be used along the laying tract in order to provide continuous signals for the DP system on the composite vessel 5 in order to facilitate continuous correction of the laying operation.
• the laying of the pipe 8 is thereafter performed as a usual laying operation from a single hull laying vessel. Model tests may be used in order to find the best hull and o geometric relationships for the composite vessel.
• the barge is brought back to the coiling base by a common tug boat while the AHV is demobilised for other jobs if this is most expedient. If such jobs are not available at profitable rates, 5 the DP vessel may of course also be used for the towing operations.
• anchor handling vessels for the DP vessel 2 particularly in waters with more inclement weather conditions like the North Sea, use may be made by a submergible DP-controlled heavy lift vessel.
• Such a constellation is illustrated in Figures 4 and 5, where the barge 1 is placed on the deck of a heavy lift vessel 24 such that a minor part of the barge with the pipe ramp 9 extends outside the edge of the deck.
• the heavy lift vessel 24 positions the pipe 8 as during a common laying operation from a conventional single hull lay- ing vessel .
• the heavy lift vessel may advantageously be of the type which can lift about 15000 tons.
• the barge 1 When the laying operation is completed, the barge 1 may be brought back to the coiling base by a common towing vessel, while the heavy lift vessel is demobilised for other jobs. Also in this case the heavy lift vessel may be used for the transportation phase if this is indicated by the job situation.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Ocean & Marine Engineering (AREA)
• Earth Drilling (AREA)
• Polarising Elements (AREA)
• Devices That Are Associated With Refrigeration Equipment (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
• Electric Cable Installation (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19913621

Family Applications (1)

Country Status (4)

Cited By (3)

Citations (6)

• 2002
  • 2002-05-10 NO NO20022243A patent/NO317541B1/no not_active IP Right Cessation
• 2003
  • 2003-05-09 WO PCT/NO2003/000152 patent/WO2003095880A1/en not_active Application Discontinuation
  • 2003-05-09 AU AU2003232690A patent/AU2003232690B8/en not_active Ceased
  • 2003-05-09 MX MXPA04011185A patent/MXPA04011185A/es active IP Right Grant

Patent Citations (6)

Non-Patent Citations (1)

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