Physical properties dynamics of oil sands products and their influence on spill response

Abstract

If current trends continue, Alberta oil sands production could increase by a million barrels per day in the next decade. Demand would then overwhelm existing domestic transport routes, and one would predict pressure to mount for new pipelines and expansion of existing ones, and increased tanker traffic to provide access to new overseas markets. In Canada, mechanical recovery is the primary oil spill response option. It is effective, but only under relatively calm seas. Alternative oil spill countermeasures exist, such as chemical dispersant and in situ burning. The analysis here indicates that, if approved through legislation and applied in conditions to achieve best results, these alternatives could considerably reduce environmental and socio-economic impacts than mechanical recovery alone. Current Canadian contingency plans lack the decision-making tools to predict the effectiveness of oil spill countermeasures to treat and assess the risk from spills to protect sensitive aquatic areas. Blended bitumen and conventional oils were selected and their physical properties and chemical compositions, relevant to ecological impacts and oil spill response, were characterized. Empirical models were developed to predict the rate and decay of water soluble chemicals released from spills of bitumen blends to provide implications for risk assessments. A decision matrix was created from newly developed models for the time evolution of the density and viscosity of oil to forecast windows of opportunity, where countermeasures are effective at treating spills and the conditions under which oil would sink in aquatic areas. Also, evaluation of seasonal climatic factors revealed that sunlight exposure, wind speed and temperature had a significant (p<0.05) influence on weathering of oil. A new oil dispersion model was developed to estimate effectiveness values for dispersant to treat oil at points in time after its release. These new developments offer to strengthen critical elements that are often missing in contingency plans.