Quantitative Approach to the Preliminary Risk Analysis of Environmental Contamination Caused by Oil Spills from Offshore Oil and Gas Installations

Despite improvements in oil spill prevention, recent data confirm that oil releases at sea are still a concern due to the severe environmental contamination potential. Regulations and standards addressing the safety of offshore oil and gas operations against major accident hazards require assessing and minimizing the risk to the environment caused by oil spills, as well as proving the effectiveness of emergency response plans. The present study proposes an innovative approach to the preliminary risk analysis of environmental contamination due to offshore oil spills, capable of orienting the engineering design of offshore installations and assessing the risk mitigation derived from the introduction of different safety barriers and emergency response strategies. New specific risk indexes and a novel procedure for their calculation were developed. The risk indexes are based on both the frequencies and the consequences of the spills, quantified as oil masses in each marine compartment. The approach allowed for obtaining robust risk indexes, also suitable for guiding the application of detailed oil spill risk assessment methods. A case study is presented to demonstrate the potential of the new approach.