Quantification of Oil Spill Risk

The identification and evaluation of oil spill risk is important for contingency planning, as well as for the decision-making processes inherent in spill risk management. It needs to encompass both the probability of oil spills occurring under a number of types of circumstances, along with the potential consequences or impacts of the oil spillage. The quantification of oil spill risk provides policy makers and officials with more objective measures of probabilities, consequences, and overall risk to make informed decisions. Each potential source of oil spillage presents its own challenges for measuring the components of risk. This chapter presents state-of-the-art approaches to risk quantification for four varied spill sources-vessels, oil wells, sunken shipwrecks, and crude oil trains to demonstrate varied approaches.For vessel spills, risk analysis includes calculating the probabilities of vessel accidents that may result in spills through vessel traffic studies, coupled with outflow analyses that determine the probability of spillage and the volume of oil released. The consequences of vessel spills can be quantified through oil spill trajectory, fate, and effects modeling.Determining the probability and magnitude of well blowouts can be accomplished through the application of a fault-tree model. Again, the consequences of spillage can be determined with oil spill trajectory, fate, and effects modeling.Sunken wrecks containing oil present a unique form of spill risk. The wrecks may or may not leak or release oil in some future time until corrosion or disturbance breaks the vessels\u27 bunker or oil cargo tanks. The probability of spillage is dependent on evaluating the factors that may lead to a release. Spill trajectory, fate, and effects modeling can be used to predict potential spill consequences.The dramatic increase in the use of unit trains to transport crude oil in large quantities, coupled with the potential for accidental spills with devastating consequences of fire and explosion, have led to an urgent need to quantify risk. Again, modeling tools can be used to assist decision makers and planners in assessing this risk