Following the 2010 Deepwater Horizon (Macondo) oil spill incident it became clear that further focus is required in order to understand and control blowout risks. The control measures are also essential in reducing potential environmental consequences given a blowout event. The latest development in well capping techniques indicates that this might be a viable technical solution for controlling subsea oil and gas well blowouts. The limited field experience with this technology makes it however difficult to presume the effectiveness of the technology as an environmental risk reducing measure. It is assumed that successful implementation of a capping device, given a subsea blowout, would reduce the blowout duration, and thereby limit the total amount of hydrocarbons released into the environment. By combining OPERAto, a dynamic tool for assessing environmental risks from offshore oil and gas activities, and an in-house blowout duration model, the authors have evaluated the use of capping as an environmental risk reduction measure. Uncertainties related to capping used as a solution for subsea blowouts are also discussed.

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A near real-time environmental calculation of oil spill risk along the entire coast of Norway is developed as the EnviRisk model. Previous risk assessments utilize older decision models and repeated manual calculations that are costly as well as not accounting for the complexity of and changes in, ship traffic. Furthermore, cloud-providers have enabled enough data ingest and processing power to utilize high resolution shore and satellite based AIS data (Automated Identification System), to develop more dynamic and accurate risk calculation models than before. EnviRisk builds upon AISyRisk, an automated risk calculation model for marine traffic developed by the Norwegian Coastal Administration (NCA) and DNV GL. AISyRisk, includes a long-term data collection on probability of ship accidents and consequences for fatalities and oil spills for Norwegian waters (Norwegian Coastal Administration 2020). From AISyRisk, the probabilities for a certain oil spill (location, oil type and volume) is developed further to assess the environmental consequence in the EnviRisk model. As part of EnviRisk, extensive oil spill modelling is being performed in the cloud with the open source OpenDrift model (https://github.com/opendrift/opendrift/wiki) released by the Norwegian Meteorological Institute. This, combined with environmental sensitivity for both seabirds, marine mammals, fish and shoreline habitats, makes it feasible to quantify the environmental consequence and risk. Environmental risk is presented on a 10x10 km grid for the previous month of ship traffic and also accumulates statistics for risk over time. This paper presents the automated oil spill modelling and environmental risk calculation in EnviRisk. The method builds upon previous risk assessments for NCA for the Norwegian Coast (Braathen and Brude, 2011), for Svalbard and Jan Mayen (Braathen et. al., 2014) and for Greenland for Defence Command Denmark also in 2014 (Eikeland et. al., 2014). The approach is significantly improved particularly with respect to the oil spill modelling. Updates of AISyRisk and EnviRisk data and calculations are done monthly and the results published on a web portal administered by the Norwegian Coastal Administration where aggregated results are publicly available.