SBM Atlantia Introduces New FPSO Deepwater Mooring Technology

SBM Atlantia introduces its latest FPSO mooring technology aimed at further enabling the development of deep and ultra-deepwater reserves.

Called the MoorSpar system, the device is a disconnectable FPSO mooring system that makes possible the use of lower-cost, efficient steel catenary risers (SCRs) in deep and ultra-deepwater harsh environments such as the Gulf of Mexico or Southeast Asia.

The MoorSpar unit consists of a truss structure set atop a long, slender buoy and moored to the seafloor by a combination of lateral polyester lines and vertical tethers. The FPSO is connected to the facility through an articulated yoke system linked to a main roller bearing situated below a gimbal table at the top of the MoorSpar unit. This arrangement accommodates the vessel’s roll and pitch motions, while allowing the FPSO to weathervane. SCRs are, in turn, connected to the MoorSpar unit at riser porches located along the keel of the buoy. The risers are then linked to internal piping which is routed up through the central column and then across hard piping and swivels to the FPSO. The MoorSpar system is also suitable for high pressure and high temperature reservoirs as it avoids the use of flexible jumpers and risers.

“Typically, up to now deep and ultra-deepwater FPSOs had no choice but to use expensive riser towers or hybrid riser systems as the vessel’s heave motions prohibit the use of SCRs,” says Philippe Lavagna, SBM Atlantia engineering project manager for the MoorSpar system. “The MoorSpar system de-couples the motion of the vessel from the risers, thereby basically eliminating fatigue issues, while at the same time allowing for disconnection in the event of a storm.”

The MoorSpar system was successfully model-tested at the MARIN facility in the Netherlands in 2007 to confirm the basis of design and feasibility of connection and disconnection.