Mammoet has loaded out a 12,733-tonne jacket for the Sao Vang and Dai Nguyet (SVDN) gas and condensate development project, located offshore Vietnam.
Mammoet was contracted by PTSC Mechanical & Construction Company. The company’s project scope included the load out of the Sao Vang jacket; installation of the flare tip and living quarters module; and the integration of the topsides.
The first phase involved the load-out of the jacket. Considering the weight of the unit, extensive engineering preparations were needed, said Mammoet. Due to its large dimensions – 131 m x 81.7 m x 56 m – Mammoet utilised a strand jack load-out system to provide a feasible and cost-effective solution.
The jacket was built with a launch truss on skid beams. Breakout jacks were used to initiate the movement of the jacket from its assembly position, before strand jacks and winches began the main pulling operation. It was loaded onto a barge that was equipped with external high-capacity submersible ballast pumps, which were synchronised with the barge’s internal pumping system. The internal ballast system was then used for de-ballasting with Mammoet monitoring and controlling ballasting from the barge bridge.
The topside’s 100 m-high vertical flare stack needed to be fitted with its flare tip. Installation was performed by Mammoet’s Conbit team.
The living quarter module was transported via 56 axle-lines of SPMTs to the topside area, where four Mega Jack 5200 towers were positioned. The module was then placed on top of the Mega Jack 5200 system for lifting to a height of 18.6 m. Next, the Mega Jack towers were connected by link beams to the topside, allowing the module to be skidded into its final location on the deck.
Mammoet was also able to load-out the entire topside structure, by this point weighing 15,608 tonnes, using the same strand jack equipment that had been employed for the earlier jacket load-out.
The heavy lift specialist said this was a highly complex project involving a wide range of services, people and equipment mobilised from various Asia Pacific countries, the Netherlands and the UK.