Advanced, SCR-Friendly Semisubmersible FPU for Ultra-Deepwater
Atlantia’s new SCR-friendly semisubmersible FPU is the first ultra-deepwater structure designed specifically to produce acceptable stresses in large-diameter steel catenary risers.
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The design effort began with an exhaustive analysis of SCR motions and stresses, defining critical areas that are adversely affected by extreme motions. Atlantia engineers then developed a deep-draft hull design, drawing upon the expertise of SBM Offshore Group sister company GustoMSC-OceanDesign, an experienced designer of marine drilling rigs.
Instead of a conventional design approach driven by payload capacity, Atlantia focused on ways to limit motions that adversely affect SCRs and SCR connections. The result is a deep-draft, four-column, ring-pontoon hull design that will support large facilities while extending SCR fatigue life.
The deep-draft design was verified by thorough global analysis and model-testing performed in late 2003, and detailed engineering of the first 37,000-ton-displacement FPU hull for 8,000-ft-deep water has been completed.
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Other features
- More economical to fabricate and install than conventional semisubmersible structures
- SCR porches on the outside of the pontoons facilitate SCR installation
- Structure draft and height are optimized for fabrication yard docks and cranes and for tow-out clearances
- The deck and hull can be integrated at quayside and wet-towed to the installation site, eliminating offshore heavy lifts
- Like Atlantia’s successful SeaStar TLP, the new semisubmersible FPU hull is modularized for fast, economical fabrication
- The modular hull design is easily scalable for facility weights beyond 12,000 tons
- Atlantia’s turnkey EPCI project experience minimizes risksMaximizing SCR fatigue life