Brent Delta platform removed from legs By Kevin Keane

BBC Scotland's environment correspondent Published duration 28 April 2017

media caption The platform was lifted on to a huge purpose-built ship which will transport it to England to be scrapped

The first major decommissioning project in the North Sea has been completed with the removal of the Brent Delta platform from its legs.

It has been lifted on to a huge purpose-built ship which will transport it to England to be scrapped. Shell wants to leave the legs in place.

The 24,000 tonne Brent Delta platform topsides sat on a three-legged gravity-based structure in 140 metres of water.

The platform lies 115 miles north east of Shetland.

image copyright Allseas image caption Pioneering Spirit approaching Brent Delta

image copyright Allseas image caption Ship approaches Brent Delta at night

image copyright Allseas image caption Pioneering Spirit moving in around the Delta

It is one of four which is due to be removed from the field in the coming years.

Unusually for a platform, the legs of Brent Delta are made of concrete which makes it much more difficult to decommission than one with steel legs.

Allseas, the company which operates the decommissioning vessel Pioneering Spirit, said it had set a world lifting record with the removal of the platform.

The topsides have now been sea-fastened on board the vessel for transportation to Teesside.

image copyright Allseas image caption Connecting the yokes to the platform

image copyright Allseas image caption Yokes connected to the platform

image copyright Allseas image caption All yokes connected, pre-tensioning and deballasting

image copyright Allseas image caption Fast lift of the Delta topsides

What is Brent Delta?

Brent Delta was one of the first platforms to be built in the very early days of Britain's oil and gas industry.

It sits about 115 miles (185km) north-east of Shetland in a cluster of four platforms which make up the Brent field. Its sister, Brent Bravo, produced its first oil in 1976.

At its peak, in 1982, the four platforms were producing more than half a million barrels of oil a day.

Being one of the first, it's now at the end of its life and has to be removed.

Brent Delta is the first major piece of infrastructure to be decommissioned in the North Sea.

More than 100 platforms are forecast to be completely or partially removed over the next decade in the waters of the UK and Norway.