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Maureen platform decommission

North Sea, Untied Kingdom

Year

2001 - 2003

Duration

2 years

Cost

£200m

Location

Untied Kingdom
Project achievements

Solved the problem

Remove an oil platform that had reached the end of its working life

Used engineering skill

Design industrial buildings and machines on a grand scale

Float an oil platform up from the seabed and tow it away

The Maureen oil field – located in the North Sea, 163 miles north east of Aberdeen - began production in 1983.

After 16 years, the field became uneconomic in 1999.

International agreements meant the Maureen oil platform – a steel structure weighing 112,000 tonnes and used for drilling, storage and production – had to be removed from the now-defunct oil field.

The facility had originally been constructed at Hunterston dry dock in Scotland and then towed to Loch Kishorn in the Highlands to have the deck fitted. From there, it was towed out to the Maureen oil field.

The platform had been designed to be refloated but getting it off the seabed and away from the field was still a major undertaking for engineers.

The 116m-tall steel gravity platform was a complex structure. Standing in 96m of water, it was made up of three steel storage tanks of 27m diameter, connected by a steel frame.

The three tanks had a combined storage capacity of 630,000 barrels of oil and stood on steel bases measuring 47m across.

The removal scheme saw engineers raise the platform from the sea bed and tow it to Stord Island in Norway to be broken up. At the time, it was the largest decommissioning project of any offshore installation in the world.

Maureen Platform Decommissioning

ICE member and graduate engineer for HBL Associates, Husain Bensaud, tells us about the decommissioning of the Maureen Steel Gravity Platform previously situated in the North Sea. Engineers designed the Maureen Steel Gravity Platform as a structure which would float during the temporary installation and removal phases in order to make it re-usable on decommissioning.

Did you know …

  1. The Maureen platform was the largest steel structure in the North Sea at the time it was decommissioned.

  2. The platform was the first to be removed under the 1998 Oslo/Paris Convention for the Protection of the Marine Environment of the North-East Atlantic, commonly known as OSPAR.

  3. The treaty says oil companies must remove any redundant platforms weighing more than 10,000 tonnes from the North Sea.

Difference the project has made

The project successfully removed an oil platform from the North Sea which had come to the end of its working life.

The scheme meant Phillips Petroleum and its partners had complied with international treaty regulations.

How the work was done

Maureen’s owners started to plan for decommissioning in 1993 – eight years before the platform was removed.

Engineers took just 60 hours to carry out the first stage of the work – lifting the platform off the seabed.

The project team began this first phase by injecting water under Maureen’s three bases while deballasting seawater in the structure’s three tanks. Deballasting means the seawater was pumped out of the tanks to make them lighter and help the platform float.

Once Maureen was floating and stable, six tugs towed the platform 165 nautical miles to a deep-water construction site at Stord Island in Norway, where the facility was broken down for scrap.

Workers recycled a separate concrete loading column from the platform as a breakwater for the island.

People who made it happen

  • Clients: Phillips Petroleum UK Ltd, BG Group plc, Pentex Oil UK Ltd, TotalFinaElf Exploration UK, Agip UK Ltd
  • Project manager: Peter Broughton, ICE Fellow

More about this project