Operations in 4000 m Water Depth For The Prestige Wreck Fuel Recovery Project

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe tanker Prestige, carrying 77,000 Tm of heavy fuel, sank in 3,850 m of water 153 nautical miles off the north coast of Spain in November 2002. The ship broke apart and, for several months afterward, large quantities of spilt fuel washed ashore in Galicia and elsewhere.Repsol YPF, although in no way connected to the vessel or its cargo, was appointed by the Spanish government to recover the fuel remaining in the wreck. Repsol YPF subsequently selected Sonsub as its main contractor.This paper describes the required operations performed during the final wreck fuel recovery project, mainly focus ing on deepwater (up to 4,000 meters) and offshore operations.A project overview and details of other aspects of the project are described in separate papers, see References.Innovative deepwater equipment and procedures were involved during these operations, both due to water depth and the atypical activities to be performed: several vessels required on the surface, simultaneous ROV operations in nearly 4,000 meters of water depth, the tapping onto the wreck's tanks, the transfer of extremely viscous fuel into specially designed shuttles, the recovery of these shuttles to surface and offloading them into a dynamically positioned FSO.The Repsol YPF Prestige Recovery Project has won the prestigious Energy Engineering Project of the Year at the Platts Global Energy Awards for 2004.

High-Pressure Behavior of Intermediate Fuel Oils

“…and recovering fuel operations after an accident, as in the case of deep oil spills such as the "Prestige" tanker, 8 where modeling the temperatureÀpressure (TP) behavior or the heavy fuel remaining in the tank from the shipwreck to the ambient TP conditions is a compulsory task.…”

“…Knowledge of high-pressure viscous behavior and volumetric properties of these fuel oils is a very important issue not only for designing and simulating injection combustion systems but also for designing manipulating operations (pumping, extraction, etc.) and recovering fuel operations after an accident, as in the case of deep oil spills such as the “Prestige” tanker, where modeling the temperature–pressure ( TP ) behavior or the heavy fuel remaining in the tank from the shipwreck to the ambient TP conditions is a compulsory task.…”