Free Standing Hybrid Riser for 1800 m Water Depth

Petrobras is considering the single-line FSHR (Free Standing Hybrid Riser) design as an option for 18-in export risers in 1800 m water depth. This paper provides the background on the studies carried out to achieve confidence that the concept is feasible for such application, and explains the main features of the design that take best advantage of local practices and Petrobras capabilities. The installation studies consider a Mobile Offshore Drilling Unit (MODU) for deployment of the FSHR system. The analyses assess the allowable sea states for such operation. Another design driver is the fatigue damage due to VIV (Vortex Induced Vibrations), which will also be addressed in the paper. Model tests were performed in order to support the conclusions of the numerical analyses that established the operation window for the FSHR system deployment.