Assessment of Oil Spill Risk for Shuttle Tankers in the Gulf of Mexico

Abstract

To date, all deepwater oil reserves in the Gulf of Mexico have been developed with systems that transport oil to shore via pipelines. This paper describes the methodology used to assess the oil spili risks for a feasible alternative to these systems, a tanker-based Floating Production Storage and Offloading (FPSO) system with oil transportation to shore via shuttle tankers. This methodology provided a rational and consistent framework for combining available historical data with input from technical experts. The methodology tracked all potential sources of uncertainty, including uncertainties due to a limited quantity of data (particularly for large spill incidents), uncertainties due to any adjustments made to the data to reflect current operating practices, and uncertainties due to extrapolating data reflecting current operating practices to predict future performance. The major conclusions are that the oil spill risk for shuttle tankers is dominated by rare, large spills rather than frequent, small spills; that the confidence intervals in the results are very wide, reflecting the limited quantity and quality of historical data available to estimate frequencies for rare events; and that the results from this study should be periodically updated because they provide a valuable baseline for future analyses of pollution risk in the Gulf of Mexico.