The FPSO Espirito Santo represents an exciting advance in ultra deepwater technology for floating systems. The FPSO, which arrived in Brazil 25 months after project sanction, is moored and operating in 1780 meters of water offshore Brazil in the BC-10 block (Parque das Conchas field development). The FPSO Espirito Santo is owned and operated by a joint venture between SBM Offshore and MISC, and leased to the BC-10 Joint Venture, operated by Shell, with partners Petrobras Brasileiro S.A. (Petrobras) and ONGC Campos Ltda (ONGC).
The Parque das Conchas project presented many challenges to successful execution of the surface host facility. These challenges include the ability to receive, process and offload heavy crude ranging from 16-42 API grade and incorporation of unique design features into the hull to increase environmental protection and prolong the life of the 1975 converted VLCC hull. The water depth of 1780 meters and demands of the complex subsea infrastructure, which relies on continuous surface supplied power and circulated oil at critical stages, required careful consideration during execution. Finally, the selection of Steel Catenary Risers (SCRs) dictated a new design for the riser interface in the turret. The facility represents the first application of SCRs tied back to a turret moored FPSO.
This paper provides a summary of the FPSO Espirito Santo design, fabrication, transportation, installation and start-up. The unique design aspects and technical challenges faced during the project execution phase for FPSO delivery are outlined. Subjects discussed include: execution planning; process facilities; hull and marine work scope; mooring system; and riser/umbilical interfaces with the host.
The methodologies selected for overcoming the key technical challenges are presented. For processing produced oil covering a wide API grade range, including low API grade heavy oil, the use of multiple process trains with input heat is detailed. The hull systems include the use of cargo tank heating for offloading of heavy crude and utilize stabilized crude as ballast to prolong the hull service life. Dedicated hull tanks for subsea flow assurance fluids (methanol and light crude) also form part of the hull design, while sponsons have been incorporated during conversion of the single hull VLCC to provide double sided protection. The turret design required the application of novel concepts to accommodate the interface with SCRs and high voltage swivels to meet the subsea equipment power demands.
