Abstract
SINTEF has conducted a re-check of Grane, Oseberg A and Oseberg C crude oils to verify the weathering studies from 1997 and 1995, respectively, and to identify any needs for updates of the weathering studies. Based on the obtained data, and compared with the previous studies, SINTEF recommend:• No new full weathering study on the Grane crude oil, though the pour point and the water uptake rate have increased a bit since 1997. However, a dispersing agent dosage test is not earlier performed. Such a test will give information about operational dosage needed for sufficient efficiency of dispersing agent.• A new full weathering study, including dispersibility testing, on the Oseberg A crude oil. The most important factors are the significant increase in density, asphaltene content and viscosity of the crude.• No new full weathering study on the Oseberg C crude oil, though the wax and asphaltene content have decreased a bit since 1995. However, a dispersing agent dosage test is not earlier performed. Such a test will give information about operational dosage needed for sufficient efficiency of dispersing agent.