Feature 2 | spars
The Perdido spar: certification ongoing
Since our article in OMT last year revealing the order for the new Perdidio
spar, we can now give you more information about the progress of this
project.
I
n 2006 Shell Offshore Inc announced
that it would develop the Great White,
Tobago, and Silvertip Fields via a Perdido
Regional Development host, located in
Alaminos Canyon, offshore Gulf of Mexico,
approximately 200miles south of Freeport,
Texas. Technip has been contracted to
provide the engineering, procurement, and
construction of the truss spar (OMT 1Q 2007,
page 18).
The Perdido hull was designed by Technip
Offshore, and is currently under construction at
Technip’s yard in Pori, Finland. The American
Bureau of Shipping (ABS) is providing CVA
fabrication survey services in this location.
The Perdido topsides have been designed
by Alliance Engineering, of Houston, and will
be constructed by Kiewit Offshore, Corpus
Christi, Texas. ABS will additionally provide
CVA Fabrication Survey services here. The Perdido DVA spar regional host.
The regional direct vertical access (DVA)
spar will be the deepest spar production facility
in the world, operating at water depths of to deepwater Gulf of Mexico applications structural elements of the hull and topsides,
nearly half a mile deeper than any other spar, because they offer increased flexibility in terms including mooring systems and suction piles,
and will be moored in approximately 2500m of of water depth capability, extending traditional as well as stability reviews.
water. The Perdido truss spar, which includes floating technology up to 3048m of water. The
a fully integrated drilling rig, is anticipated to first spars were installed in the 609m-914m risers
begin production around 2010. water depth range, but the Perdido will be Subsea engineering company, MCS, has been
The hull and decks have reportedly installed in 2382m water depth, making it the awarded a first-of-its kind contract in the Gulf
unusually been constructed as one single deepest operating spar when it is installed in of Mexico from Shell. The subsea and riser
unit, instead of as individual modules, which 2009. engineering specialists will provide certified
are then welded together. This, according to ABS has experience with nearly all spars verification for the top tension risers on the
Shell, should reduce fabrication time, as well installed in the Gulf of Mexico and the designs’ Perdido spar.
total amount of steel needed, thus ultimately different generations from caisson or classic Under new MMS requirements in the Gulf
reducing costs. to truss and cell. The truss spar is primarily of Mexico, floating platform risers must be
characterised by its space frame of tubular tested by a qualified riser certified verification
Verification members, which provides the structural agent. MCS will provide verification of the top
Floating production systems such as spars must linkage between hard tank (flotation tank) tension risers through all phases of the project;
comply with USA federal regulatory codes and keel tank, as well as support to the heave design, construction, and installation.
in order to receive a certificate of inspection plates. The heave plates provide added mass This will involve analysis, materials,
from the USCG and a permit to operate from and damping to further reduce heave motions and component selection, including any
the Minerals Management Service (MMS) and to improve stability. qualification testing needed, equipment
for operation in USA waters off the Gulf of This arrangement provides comparable inspection verification and witnessing of
Mexico. ABS has been selected to act as the strength to the classic spar designs while offshore installation.
certified verification agent (CVA) for the MMS using less steel. This allows a higher deck load, This certification and verification capability
for the Perdido spar. while delivering required motion response is part of MCS’ drive to expand its services
ABS project manager for Perdido, Mike performance. offering to capture a larger share of the
Sano, says spar systems are particularly suited ABS will perform technical reviews of the burgeoning global subsea market. OMT
16 Offshore Marine Technology 1st Quarter 2008
OMT 1stQ 08 - p16.indd 16 11/02/2008 11:47:04
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