This is a major event for the Sakhalin II project, whose three platforms are now all safely on location in the Sea of Okhotsk, northeast of Sakhalin Island. With this milestone, construction operations are nearing completion. The next step will be the beginning of the hook-up and commissioning operations, to be followed by the operations phase.
By successfully 'mating' the 28,000 tonnes topsides to its gravity base, previously placed on the seabed, Sakhalin Energy has broken its own world record set by the Lunskoye topsides installation last year. With the topsides installed on the base structure, the total height of the PA-B platform is 121 meters from the sea floor to the top of the derrick – as large as a 30-storey building.
At 07.15hrs today the PA-B topsides was set down on the legs of the concrete gravity base structure. It was controlled from the transport barge and supported by a service vessel and five tugboats. The unique T-shaped transport barge measuring 190 by 92 meters was specially built to safely carry the topsides on their 3,000 km tow by sea from the fabrication yard in South Korea. Once on the site, the barge was carefully towed between the four legs of the concrete gravity base substructure. The massive topsides were then slowly and smoothly lowered over the four legs using the so-called 'float-over' technique by ballasting down the transport barge. Special leg mating units built into the four legs allowed the topsides to achieve a perfect fit and acted as shock absorbers during the initial contact. The entire operation was executed to the highest safety standards and within the established noise levels, without any impact on the Western Gray Whale population, whose feeding grounds lie some 7 km to the west.
Congratulating the Company's staff on this achievement, Jaap Huijskes, Sakhalin II Phase 2 Project Director, said: "We are pleased to have, once again, extended the envelope for the offshore float-over installation technique. This operation is the culmination of tremendous efforts by an enormous number of people brought together to deliver this pioneering project".
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