Sea Empress: Slick behaviour
Spilled
oil extended offshore from Carmarthen Bay to Saint David’s
Head. Patches of sheen were reported as far away as Lundy
Island. During tghe first few days of March, weather conditions
were such that oil was easily kept ashore.
Oil
leaked from the bottom of the tanks that had been holed. Oil
tended to leak most with tidal movements and particularly
when the tide was ebbing. Consequently, the slick looked like
a string of smaller slicks all of which were produced at low
tide.
Oil emulsion in Tenby Bay (Source: Cedre).
Patches
were reported from time to time over a 200 kilometre stretch
of coastline but thick slicks were essentially reported in
Tenby Bay, in the western reaches of Carmarthen Bay and Freshwater
Bay. Milford Haven Bay was also oiled over a distance of about
20 kilometres. Tar balls were reported as far away as the
Irish coast but there was a high degree of uncertainty as
to their origin.
Official
observers reported that not much oil had stuck to exposed
shorelines located from the entrance of Milford Haven Bay
to Carmarthen Bay. According to AEA (Atomic Energy Agency)
Technology, mineral microparticules could have adsorbed to
oil droplets and mitigated adhesion in the process. This may
well have stabilised the oil droplets and prevented them from
recoalescing in exposed locations.
A
research programme conducted by AEA Technology will determine
whether these assumptions are founded or not.
| Crude | |
|---|---|
| Name: Forties Density in kg/l (15 °C): 0.84 API Density: 36.9 Pour point (° C): (- 12 ; + 3) Viscosity (cSt): 9.6 at 10°C, 7 at 20°C |
|
| Composition (%vol) |
|---|
|
C1-C4: 2.74 C5-95° (petrol): 9.23 95°C- 49°C (naphtha): 20.02 149-232°C (kerosene): 14.50 232-342°C (gas oil): 20.92 Sulphides (% weight): 0.32 Asphaltenes (% weight): 0.20 Paraffins (% weight): 7 V/Ni (ppm/ppm): 3/2 Residues (% vol at 343°C): 40 - Viscosity (cSt at 50°C): 102 - Sulphides (% weight): 0.40 - V/Ni (ppm/ppm): 6/46 Observations (%vol) |
| Observations |
|---|
|
Thirty
to forty per cent of the oil evaporated after 24 hours Emulsion: viscosity > 10 000 cSt in seawater after 5 days at 5°C |
Oil emulsion on the beach in Swanvilake Bay(Source: Cedre).
Last update: July
2003