Limited laboratory study of Rolvsnes in comparison with existing weathering properties of Edvard Grieg and Solveig crude oils - OC2021 A-117

A limited laboratory study of Rolvsnes crude oil has been conducted to compare the obtained weathering data with the existing properties of Edvard Grieg (previous Luno) crude oil, in addition to Solveig (previous Luno II) crude oil, from the neighbouring fields in the North Sea. Edvard Grieg has been used as a surrogate oil for Rolvsnes for environmental risk analysis and oil spill contingency. The laboratory study was performed at 13 °C). The obtained weathering data for Rolvsnes were used in SINTEF Oil Weathering Model (OWM) for preliminary predictions for comparison with the previous predictions of Edvard Grieg and Solveig. Overall, the weathering properties of Rolvsnes are comparable with Edvard Grieg in addition to Solveig. However, Rolvsnes exhibits lower emulsion viscosities compared with Edvard Grieg and Solveig, and Rolvsnes will likely form lower emulsion viscosities if spilled at sea. The predicted emulsion viscosities of Edvard Grieg and Solveig can be considered as a conservative alternative for Rolvsnes. Based on the very limited dispersion test on Rolvsnes, a viscosity limit for when the oil is considered as poorly dispersible was estimated and used for estimating time-window for operational use of dispersant. This should be verified with an extended test matrix for testing the dispersibility of Rolvsnes.