LONDON�Coflexip Stena Offshore International SA, a French subsidiary of the Coflexip Stena Offshore Group, yesterday wrapped up the delicate subsea operations aimed at pumping out some 11,245 tonnes of heavy fuel from the tanker Erika, which sunk in high seas off the coast of Brittany, France last December.
Franco-Belgian oil giant TotalFinaElf awarded the consortium of CSO and Stolt Offshore AS a clean-up contract in April to "recover and neutralize" the fuel remaining in the two sections of the Erika wreck, separated by some 10km in 125 m of water.
The CSO Constructor completed the contract workscope with the removal, by divers, of all subsea structures used in the pumping operations.
CSO's work on the Erika started in June with a survey of he wreck sections using a Triton XL ROV and preparations to the its hull involving drilling and installing 64 valves though which the fuel could be safely recovered. Over the intervening 2 months, pumping operations�using a process developed by TotalFinaElf�were carried out.
For this operation, CSO had mobilized 350 personnel both onshore and offshore on the seven vessels assigned to the Erika job. The subsea operations performed by divers from dynamically positioned vessels CSO Constructor and Seaway Kestrel covered over 30,000 hours of saturation of which 9,600 were spent underwater working on the wreck's two sections.
The government enquiry in January by the Sea Accidents Investigation Office, an division of the French Ministry of Construction, Transportation, and Housing, into the sinking, concluded the Erika "broke apart most likely because of structural weakness."
TotalFinaElf is spending some 850 million francs on clean-up operations linked to the accident, including 500 million francs on "neutralization" of the wreck, and 200 million francs on disposing of the heavy fuel and waste materials onboard.