Black Marlin completes trouble-free mating of MUDA deck
Last summer, Dockwise successfully delivered and installed the giant topsides for Carigali-Pttepi (CPOC)’s MUDA processing platform in the Gulf of Thailand.
The float-over operation was the culmination of a two-year- long project that involved over 100,000 man-hours of work and numerous design issues, notably those related to the mooring phase.
TheBlack Marlin carrying the MDDP platform topsides.
Due to the size of the MDDP topside (net weight 17,200 metric tons, or 18,960 tons), and the width of the jacket slot, Dockwise and CPOC had selected theBlack Marlin for the transportation. The vessel’s 42-m (138-ft) wide hull allowed it to fit comfortably between the sway fenders, leaving a 15-cm (5.9-in.) gap on both sides. Customized equipment, including modified casings, grillage, skid beams, mooring, and deck-mating equipment, were installed onboard the vessel’s main deck.
The large steel framework of grillage and skid beams, which weighed about 800 metric tons (882 tons), was designed to evenly distribute the massive loads imposed by the MDDP deck throughout the vessel’s structure. To keep theBlack Marlin and its cargo in the desired position throughout the float-over operation at the offshore location, the vessel would need to be hooked up to a pre-installed mooring system at the Muda field. Anchor moorings were used to hold the vessel in the stand-off position, with mating moorings also applied to move the vessel into the jacket slot.
Challenges that had to be addressed during design of the anchor mooring system included:
- Squall conditions
- Pipelines on the seabed hindering anchor placements
- Previously installed platforms obstructing the optimum lay-out of the anchor pattern.
As a solution, two on-site tugs were deployed to assist anchor moorings during squall periods. Damage-prevention buoys were also installed to maintain safe clearance from existing pipelines. Finally, two anchor-handling tugs placed four, 12.5-ton (11.3-metric ton) mooring anchors in position prior to the float-over.
Dockwise also introduced the Stern Entry Guide with integrated Cross-Line Catchers during this project, a first, it claims, for a float-over operation. The Cross-Line Catchers removed the need for disconnecting and reconnecting the aft mooring lines during the float-over process by guiding the lines toward the rollers.
The end result was a straightforward installation program that was completed within 12 hours.
Offshore Articles Archives
View Oil and Gas Articles on PennEnergy.com