The Spar That Upended Itself — Installing Shell's Perdido Platform
Alaminos Canyon, Gulf of MexicoDeepwater SparInstalled August 2008
Most floating platforms are set upright by an external force — a crane, a controlled tow, a mechanical jacking system. Perdido's hull did it differently: it arrived in the Gulf of Mexico lying on its side, and stood itself up by flooding its own compartments in a deliberate sequence, with no crane involved in the rotation at all.
Built by Technip at Pori, Finland, the hull was carried horizontal aboard Dockwise's heavy-transport vessel Mighty Servant 1 across roughly 8,200 miles to Kiewit Offshore Services' yard in Ingleside, Texas, before sailing on to its final site at Alaminos Canyon Block 857 — around 200 miles south of Freeport, in water deep enough that the platform still ranks among the deepest spar-type structures ever installed.
~7,820 ft
Water depth
118 ft
Hull diameter
9,773 short tons
Topsides, single lift
9
Polyester mooring lines
Stage 1
Fabrication and transport
The hull was built at Technip's Pori, Finland yard between November 2006 and May 2008, then shipped horizontal, deck-loaded, aboard Dockwise's semi-submersible transport vessel Mighty Servant 1 to Kiewit's outfitting yard in Ingleside, Texas — arriving mid-June 2008.
Stage 2
Soft-tank flooding
Once towed to site, tugs opened plugs on a soft tank at the base of the hull, letting seawater enter under control. This induced a deliberate, protective roll — designed to safeguard equipment already installed inside the hull — bringing the spar to roughly a 15-degree incline within about an hour.
Stage 3
Hard-tank ballasting to vertical
Heerema's crane vessel DCV Balder then pumped ballast water into the hull's hard tank at roughly 1,500 cubic metres per hour — around 20,000 cubic metres in total — sequentially draining higher tanks into lower ones to preserve stability as the spar rotated the rest of the way to full vertical. No mechanical lift or external rotating force was applied; the hull turned under its own shifting centre of gravity as it flooded.
Stage 4
Mooring and storm-safe condition
Nine polyester mooring lines secured the spar in place, three of which had been pre-installed at their anchor locations before the hull even arrived on site — a sequencing choice aimed specifically at getting the platform to a storm-safe condition as quickly as possible once upended.
Stage 5
Topsides installation
The topsides — a single-piece module of 9,773 short tons (about 8,866 tonnes), the heaviest single lift in the U.S. Gulf of Mexico at the time — was installed separately in March 2009 by Heerema's semi-submersible crane vessel SSCV Thialf, sailing from Ingleside on 8 March and completing the lift five days later.
Timing note
The hull was upended and moored in August 2008, directly ahead of Hurricane Ike making landfall on the Texas coast that September. The storm flooded Shell's Galveston supply base and heliport, forcing a shift of helicopter operations to Corpus Christi — a reminder that even a carefully sequenced ballast-controlled installation still has to survive the hurricane season it was scheduled inside of.
Perdido's hull never touched a crane to stand up. It stood itself up, one flooded compartment at a time.
First production began in March 2010. Perdido was described at commissioning as the world's deepest floating oil and gas production platform — a record for floating production overall that Shell's own Stones development, a disconnectable FPSO in roughly 9,500 ft of water, later surpassed in 2016. What hasn't changed is the installation method: a self-upending spar hull, floated to site and stood vertical by nothing more than sequenced, controlled flooding, remains one of the more distinctive heavy-lift stories in deepwater installation.
SSCV Thialf alongside the Perdido spar hull during installation, Gulf of Mexico, March 2009. Resized from the original for web display. Photo: BoH, Wikimedia Commons, CC BY-SA 3.0.
Sources:Guinness World Records — deepest spar platform by ocean depth; Oil & Gas Journal — contemporaneous account of the upending and mooring sequence; Offshore Magazine. Published water depths range from about 2,438 m to 2,450 m depending on the reference point.
Frequently Asked Questions
Sources differ: Oil & Gas Journal's technical coverage cites figures ranging from roughly 18,100 to 21,000 tons for the hull alone, depending on which project paper is referenced. The topsides added a further 9,773 short tons (about 8,866 tonnes) in a single lift — at the time the heaviest single-piece topsides lift in the U.S. Gulf of Mexico. The combined floating structure, including ballast and outfitting, is cited at around 50,000 tons.
In two ballast-controlled phases. First, tugs opened plugs on a soft tank at the hull's base, letting seawater in under control to bring the spar to roughly a 15-degree incline within about an hour. Then Heerema's crane vessel DCV Balder pumped roughly 20,000 cubic metres of ballast into the hull's hard tank at about 1,500 cubic metres per hour, sequentially draining upper tanks into lower ones, until the spar reached full vertical. No mechanical lifting or rotation was involved — the hull rotated under its own shifting weight as it flooded.
Perdido sits in roughly 7,820 ft (2,384 m) of water at Alaminos Canyon Block 857. At installation in 2008, it was described as the world's deepest floating oil and gas production platform. That overall record has since been surpassed — Shell's own Stones development, a disconnectable FPSO in the Gulf of Mexico that came online in 2016, operates in roughly 9,500 ft of water. Perdido's narrower claim as one of the deepest spar-type platforms remains widely repeated, though not confirmed here against a current primary source.
Shell operates the Perdido host platform with a 35% working interest. Chevron U.S.A. holds the largest share at 37.5%, and BP Exploration & Production holds 27.5%. The subsea fields tied back to the host — Great White, Silvertip and Tobago — carry separate, field-level partner interests.
The hull was upended and moored in August 2008, directly ahead of Hurricane Ike making landfall on the Texas coast in September. The storm forced Shell to shift helicopter operations from a flooded Galveston base to Corpus Christi and disrupted onshore logistics — a reminder that Gulf of Mexico installation schedules are planned around, and sometimes still caught by, the same hurricane season the region is defined by.
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