Prediction of Oil Spill Occurrence Probabilities in the Alaskan Beaufort and Chukchi Seas OCS

Abstract

Probabilistic estimates of oil spill occurrences are used in the development of environment impact assessments for possible future developments in the US Chukchi and Beaufort Seas. Due to the embryonic state of offshore oil development in this region, it was not possible to base these oil spill probability estimates on empirical data. Rather, statistically significant non-Arctic empirical data from the US Gulf of Mexico and world-wide sources, together with their variance, were used as a starting point. Next, both the historical non-Arctic frequency distributions and spill causal distributions were modified to reflect specific effects of the Arctic setting, and the resultant fault tree model was evaluated using Monte Carlo simulation to adequately characterize uncertainties treated as probability distribution inputs to the fault tree. This paper summarizes the methodology and gives results of its application to the estimation of oil spill probabilities and their characteristics for the Chukchi and Beaufort Seas region for typical future offshore development scenarios.