Perdido spar, Gulf of Mexico

Perdido is a floating oil platform in the Gulf of Mexico, operated by Shell. It is moored in about 2,450 m of water, which made it the deepest floating oil platform in the world when it began producing oil in 2010. Perdido is Spanish for 'lost'. It is a spar, a tall floating cylinder held in place by cables fixed to the seabed.

The platform sits above the Perdido fold belt, a rich area of oil and gas, about 320 km from shore. It acts as a hub for three fields: Great White, Tobago and Silvertip. At its peak it processes about 100,000 barrels of oil equivalent a day.

Built in two parts

The spar hull, weighing about 22,000 tonnes, was built in Pori, Finland, and shipped about 13,200 km to the Gulf. The topsides, weighing 9,500 tonnes, were designed and built separately in Corpus Christi, Texas. In March 2009 a giant crane vessel, the Thialf, lifted the topsides onto four posts on the spar. The temperature difference between cold Finland and hot Texas meant that parts expanded differently, so computer-guided lasers helped line things up.

Working in the deep

The platform pumps oil from 35 subsea wells, 22 of them beneath the spar. They are linked by 44 km of seabed pipelines and five flexible pipes, called risers, that carry oil up to the platform. It can adjust the tension of its mooring cables to shift around within an area about the size of a soccer field, so that it can sit directly above one of the wellheads.

On the globe

Look for the western Gulf of Mexico, off the coast of Texas.