From Reservoir Characteristics, Through Environmental Risk Assessments to Oil Spill Response – Lessons Learned from a Comprehensive Systematic Development by an Operator

Statoil is the largest operator on the Norwegian Continental Shelf, is operating 42 assets and has an exploration activity in the order of 20-25 wells per year. In 2011, Statoil decided to undertake a full review of the basis for the oil spill response level for their activities, and establish a fully documented, transparent documentation of their approach. In Norway, operators are required to perform environmental risk and oil spill emergency preparedness assessments for all activities, as a basis for oil spill response plans. These assessments are of a complex and quantitative nature, and it has for a while been realised that there needed to be a better link between well characteristics and the oil spill response level. In the early phase of the development, it was decided to separate issues according to their nature. Issues related to company policy on overall level of spill response were identified and addressed in a separate process, as were issues relating to science and technology. From this, further work proceeded on the three main topics a) Policy decisions on spill response scaling criteria, b) algorithms for calculating effect of various response measures, and c) fact finding on issues of operational windows, capacities and effectiveness. As part of the development, all Company fields in production were reviewed, and oil spill response level adjusted and extended to include near shore and shoreline response plans. Sensitivity studies were undertaken to identify critical elements in the progression from blowout and kill studies to near shore spill response plans. Lessons learned include the overall importance of selecting correct data on reservoir characteristics, sufficient resolution in oil spill modelling, and applying consensus values for spill response capabilities throughout the assessment process. To ensure an adequate basis for near shore spill response planning, GIS technology was applied to produce a set of thematic spill response maps, in A1 size PDF format, for 37 of the most sensitive areas along the Norwegian coast. A strategic plan was also developed for each area. All maps, documentation, GIS data sets and other results of this development work has actively been made available to operators on the NCS, to the Authorities and to spill response organizations.