Its not, its a drilling ship and a refinery all in one if i remember rightly.

It weighs 300,000 tonnes.
It is 305.1 m long.
Has a moulded breadth of 58 m
And it is a Floating, Production, Storage and offloading vessel (FPSO) Has the capability to process 225 000 barrels of crude oil a day and can export 1 million barrels onto a shuttle tanker at the rate of 1 million every 24 hours. And it is permanantly moored in the Niger Delta oil field that Shell have.