The Prestige Wreck Fuel Recovery Project
This article is intended to provide a detailed overview of the recovery project devised to extract the remaining in the wreck of the Prestige tanker. hydrocarbons The ship, carrying some 77,000 Tm of heavy fuel oil broke up and sunk in 3850 meters water depth in November 2002, 150 miles off the north western coast of Spain. During the sinking, and for a period of several months afterward, a large amount of fuel was spilt ending up mainly on the shores of Galicia. Repsol YPF, though in no way connected to the vessel or its cargo, was appointed by the Spanish government to recover the fuel remaining inside the wreck. Later Repsol YPF selected Sonsub as the main contractor. The initial campaign, carried out in 2003, involved the design and construction of the tools required to operate a those depths, sealing off all remaining leaks in the wreck, conducting a comprehensive data acquisition and research campaign that included measuring the fuel remaining inside the wrecks tanks and carrying out a pilot test of a novel batch extraction method which involved the development of a safe system to perforate the wrecks deck and control the extraction of fuel. The extraction of the remaining fuel was carried out in 2004 using large volume aluminium shuttles. An innovative core-flow technique was used to extract this extremely viscous fuel (some 500,000 centipoises at the shuttle offloading conditions) from the shuttles and offload it into a Floating Storage and Offload (FSO) vessel. Finally, a bio-remediation procedure to accelerate the biodegradation of the immobile fuel was implemented. Details of the different aspects of the project are described in separate papers, see References. The Repsol YPF Prestige Recovery Project has won the prestigious Energy Engineering Project of the Year award at the Platts Global Energy Awards for 2004.