In the near future PETROBRAS will install, at least, five FPSOs at Campos Basin - Brazil, to exploit its giant fields, Marlim, Albacora and Barracuda Fields, considering for each Unit an oil processing around 100000bopd and a 20-year operational life without docking. The conversion of its own oil tankers, older than 20 years, into FPSOs has been adopted, as a result of a Technical and Economic Feasibility Study. In order to guarantee a suitable performance of the Unit during the whole life, special requirements were established for structural verification of the FPSO, taking into account peculiar conversion aspects, such as previous fatigue damage as an oil tanker, thickness corrosion rates, Brazilian environmental and new cargo loading conditions. The main requirements, concerning yielding, buckling and fatigue criteria, can be gathered in four groups. First of all, a verification of the longitudinal hull-girder strength has to be performed with updated loading conditions, taking into account the loads introduced due to the new function, such as turret and process plant loads. The cargo region, the most stressed area of the hull, has also to be verified, especially in relation to fatigue analysis and new hydrodynamic forces. Regarding the load transmission between the hull and the turret at the bow region, a refined structural model and analysis of the turret region has to be carried out. New heavy structures (process plant deck, helideck, flare, cranes, etc.) are also focused. The structural requirements are presented and also compared with those established by Classification Societies.
Recent Technical and Economic Feasibility Studies (TEFS) developed for giant fields discovered at Campos Basin, offshore Brazil, have pointed out the employment of Floating Production Storage & Offloading systems (FPSOs) as the best exploitation option. Marlim, Albacora and Barracuda fields will receive up to 1998 five Units based on converted oil tankers from PETROBRAS fleet.
