Energy News June 2007

Spar Experience:
World’s Deepest Spar to be Installed with CVA Assistance from ABS

Floating production systems such as spars must comply with U.S. federal regulatory codes in order to receive a Certificate of Inspection (COI) from the United States Coast Guard (USCG) and a permit to operate from the Minerals Management Service (MMS) for operation in the U.S. waters of the Gulf of Mexico. ABS has been selected to act as the Certified Verification Agent (CVA) for the MMS for the Shell Perdido Regional Hub Truss Spar destined for GOM in 2009.

Perdido Quick Facts

ABS is acting as CVA for MMS performing technical reviews of the structural elements of the hull and topsides including mooring systems and suction piles as well as stability reviews.
The Perdido hull is designed by Technip Offshore and is under construction at Technip’s yard in Pori, Finland. ABS is providing CVA Fabrication Survey services in Pori.
The Perdido topsides are designed by Alliance Engineering of Houston and will be constructed by Kiewit Offshore, Corpus Christi, Texas. ABS will provide CVA Fabrication Survey services in Corpus Christi.
ABS is providing CVA survey and validation services at the various manufacturers’ facilities where major mooring components are being made. ABS will rely on its worldwide network of Survey Field Offices to support the project.
ABS will provide CVA survey services during the integration phases of the project, such as the mating of the topsides and the hull, and during the installation of the project in the Gulf of Mexico.

As the CVA for MMS, ABS will interface with the government agency, with the USCG as needed and with various contractors and vendors to accelerate the regulatory compliance for Perdido.

ABS Project Manager for Perdido Mike Sano says spar systems are particularly suited to deepwater Gulf of Mexico applications because they offer increased flexibility in terms of water depth capability, extending traditional floating technology up to 10,000 feet of water. The first spars were installed in the 2,000 to 3,000 water depth range, but the Perdido will install in 7,817 water depth, making it the deepest operating spar when it is installed in 2009.

ABS has experience with nearly all spars installed in the Gulf of Mexico and the designs’ different generations from caisson or classic to truss and cell. The Perdido is a truss spar design. The truss spar is primarily characterized by its space frame of tubular members, which provides the structural linkage between hard tank (flotation tank) and keel tank as well as support to the heave plates. The heave plates provide added mass and damping to further reduce heave motions and to improve stability. This arrangement provides comparable strength to the classic spar designs while using less steel. This allows a higher deck load, while delivering required motion response performance.