Sintef/IKU oil-weathering model: Predicting oils' properties at sea

Abstract

This paper describes the empirical approach used in the development of the IKU oil-weathering model (IKU-OWM). Weathering data from field trials with experimental oil spills during the past 15 years have provided the basis for the algorithms used in the model. These data, combined with a standardized laboratory study of each specific oil, including a bench-scale ("stepwise") weathering investigation, a chemical dispersibility investigation, and a meso-scale flume basin weathering investigation, form the basic input to the model. The IKU-OWM has been extensively tested and verified with results from full-scale field trials with experimental oil slicks in the North Sea in 1994 and 1995. This paper presents the correlations between the oil-weathering values predicted by the model and the ground-truth data obtained from the field trials. To obtain reliable weathering predictions, it is essential to have good laboratory weathering data of specific oils. The IKU-OWM is now extensively used in Norway to predict the changes in oil properties due to weathering under user-specifiedconditions. Predictions provided by the IKU-OWM enable oil spill personnel to estimate the most appropriate "window of opportunity" for using chemical dispersants in various spill situations. Prespill scenario analysis with the IKU's oil spill contingency and response (OSCAR) model system, of which the IKU-OWM is one of several components, has become an important part of contingency plans and of contingence training of oil spill personnel at refineries, oil terminals, and offshore installations in Norway.