Break-up threat to Brent Spar's final voyage

Shell has run into a new problem as it tries to work out an acceptable way to dispose of its giant Brent Spar oil storage buoy.

A study on the 14,500-tonne structure by the engineering consultants WS Atkins has shown that the Spar would be likely to buckle and break if the cheapest and easiest technique to bring it on shore were used.

Ever since a successful Greenpeace campaign halted Shell's attempts to sink the Spar in the north-east Atlantic just over a year ago, the giant oil company has been working on different disposal options, which include bringing it ashore and breaking it up for scrap.

In the meantime, the structure, essentially a vast, cylindrical, crude- oil storage tank more than 400ft tall, has been anchored in a deep Norwegian fjord.

Shell had been considering simply reversing the method it used to put the Spar into use in its Brent field, halfway between Shetland and Norway, back in the early 1970s.

This involved gradually letting sea water into its storage tanks in a controlled sequence, which turned it from floating on its side with a shallow draught (once it had been taken out of dry dock, where it was built) into floating on its end.

The new study, which used advanced computer techniques that were not available when the Spar was designed, has shown that the Spar would almost certainly rupture its inch-thick walls if this sequence were reversed. If it is to be brought ashore, another method will have to be found.

At a press conference yesterday, Shell UK said that 21 leading contractors from eight different nations had now received firm invitations to set out their options for disposal of the Brent Spar.

They will have to offer the best combination of minimising environmental damage, risks to disposal workers' health and safety, and cost.

Eric Faulds, Shell's decommissioning manager, said the contractors had not yet told Shell what they had in mind, but they had been selected on the basis of their reputation, previous experience and financial viability.

"When we get down to a shortlist of half a dozen schemes we want a spread of options," he said. "We don't want them all to involve bringing it ashore and breaking it up.

"I would hope we would get some fairly imaginative proposals which involve re-use of a large part of the structure intact, for example in a breakwater or a harbour."

He said that Shell had not ruled out deep-sea disposal, the option which attracted such controversy a year ago, because that might yet prove to be the best practical environmental choice.

"The world is a different place now ... and we've had so many ideas and so much interest that I'm still reasonably optimistic we can find a better alternative."

Shell said exotic suggestions such as converting the Brent Spar to a floating casino are unlikely to survive the shortlisting process, which is designed to balance safety, technical feasibility, economics, environmental impact and public acceptability. Whatever option Shell decides on will have to be approved by the Government.

Heinz Rothermund, Shell's exploration and production managing director, promised more dialogue with pressure groups and the public in selecting an option. "We have acknowledged that we originally set out to dispose of the Spar without explaining what we were doing early enough or widely enough," he said. Shell has placed a Brent Spar site on the Internet.

Although the Spar was emptied after 20 years of use, it still contains several dozen tonnes of oily sludge, much smaller quantities of toxic metals and some mildly radioactive salts which have built up on its pipework and tank linings. There is a scientific consensus that these would pose only a vanishingly small threat if the structure were to be dumped 7,000 feet below the Atlantic, as originally planned.

One of the many ideas sent to Shell over the past year has been to use the Spar as a fish ranch in a Norwegian fjord. This suggestion, received from a businessman in the fish-farming equipment business, would involve feeding fish guts and offal from fish farms to crabs, lobsters and fish, which would be encouraged to congregate in huge numbers around the sunken structure.