OSRR-527-The Effect of Warming Viscous Oils Prior to Discharge on Dispersant Performance

Experiments were conducted in 2002 and 2003 at Ohmsett The National Oil Spill Response Test Facility to assess the dispersibility of fresh and weathered Alaskan and Canadian crude oils in very cold water. Results from these experiments indicate that the crude oils tested were dispersible at near freezing water temperatures. However, there has been criticism of the findings related to the heating of the viscous oils prior to discharge onto the waters surface and subsequent dispersant application. This project will address criticism of dispersant testing at Ohmsett and has two potential benefits. First, the work will determine empirically whether or not heating viscous oil prior to testing influences dispersant performance in Ohmsett tests. Second, if there is evidence that heating the oil has any impact on dispersant performance.

The proposed project will repeat certain critical Ohmsett tests using unheated oil to determine whether the effect of preheating the oil is large enough to alter the overall conclusions of the original dispersant effectiveness experiments conducted in 2002 and 2003. Specifically this work will:

Determine the rate of cooling of slicks formed by discharging heated crude oil on cold seawater.
Compare the dispersibility of oils that are heated prior to discharge against oils discharged at ambient temperatures.
Conduct tests at Ohmsett using Alaska North Slope crude oil discharged at ambient temperatures (if heating of oil prior to discharge significantly influences dispersibility of the oil in small scale tests).