ROVworld Subsea Information

Mine under FLAGS pipeline to be removed
Date: Friday, October 28, 2011 @ 12:00:00 EDT

Mine under FLAGS pipeline to be removedFollowing a new study on an unexploded second world war mine lying alongside the FLAGS pipeline (Far North Liquids and Associated Gas System) in the North Sea, Shell has deployed a vessel to keep a continuous watch on the site.

There is no platform or rig in the vicinity, but occasionally fishing vessels may pass near the site. The guard vessel will ensure a safe distance is maintained between any passing vessel and the site.

Shell became aware of this unexploded ordnance in 1993. Since that time the company has regularly inspected the site and sought professional advice on how best to proceed. The consistent advice the company received was to leave the mine in position and continue to monitor it periodically.

The development of new technology means that Shell believes it may now be possible to remove the mine. Shell is considering technical options for the safe removal and disposal of the unexploded ordnance. A decision on how best to proceed is expected before the end of the year. The British-made mine was first discovered in 1993 and inspected by the Royal Navy which advised leaving it in place. Shell met with the HSE, the DTI (now DECC), Grampian Police and the Royal Navy on this issue.

There have been a number of subsequent inspections, carried out by Ramora UK, a company specialising in this work. All of these have concluded the mine should be left in place as it was stable, and the associated risks of removing it outweighed those associated with leaving it in position.

New technology has been developed since the mine was first discovered which may enable removal at the water depth in which the mine is lying.

The FLAGS (Far North Liquids and Associated Gas System) pipeline is a natural gas pipeline in the North Sea. It is used to transport liquids and associated gas from a number of platforms including the four Brent platforms. Shell's Brent Bravo is the pipeline's starting point and it terminates at St Fergus, near Peterhead. Natural gas from the Norwegian Statfjord field is fed through the Tampen pipeline and Gjoa/Vega through the Gjoa pipeline, linking Norwegian and UK gas trunkline networks.

The FLAGS pipeline was completed in 1978 and commissioned in May 1982.

This article comes from ROVworld Subsea Information

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