FPSO Dalia

On 16th February 2008 at 11 pm, a crude oil spill occurred at a loading buoy connected to the platform Dalia, located 70 nautical miles off the coast of Angola in Africa. The incident occured during a crude oil transfer operation to a tanker. A crisis unit was set up and British, South African and French technical experts were sent on site.

The Dalia is a floating production, storage and offloading (FPSO) unit capable of processing 240,000 barrels a day.

Response

Within the first few hours following the spill, chemical dispersants were applied to the slick. Dispersion operations could not last for more than a week due to the presence of surface active agents in the product spilt. These agents are added to the crude oil during its treatment when it exits the well. The dispersant spraying operations were followed by operations to recover the remaining undispersed oil.

Meanwhile, the crisis unit prepared for oil to be washed up on the shore by conducting aerial surveys in the areas at risk. 14 river mouths were considered sensitive, especially in areas of human activity (villages, fisheries etc.). The resources required were assessed in order to prepare for response operations in case they proved necessary.

In the area in question, drift simulations were particularly complex to carry out, due to the very particular ocean characteristics, with a stratified structure as well as great variability in the water column and at the surface.

Aerial observations were used to monitor the drift and evolution of the slicks. These observations were compared to the results of modelling.

On 4th March, the remains of the oil slick, which had until now been drifting towards the coast, was pushed back by the strong flow of the Congo River (which has a current speed of around 6 knots). The slick gradually moved away from the coast, to a distance of around 200 km. No oil was reported on the shoreline.

Source:

- Mer et marine