A Robust Model for the Assessment of Oil Spill Hazards over Land and Water Bodies

Oil spills over land and water bodies are some of the most relevant hazards that should be considered when implementing oil production and transport projects. However, the development of robust, versatile, and efficient tools for carrying out this type of hazard assessment is a challenge for geophysical modellers due to the complexity of the oil flow over hybrid terrain–water surfaces. This work presents a versatile Eulerian approach to simulating the transport of an oil layer flowing over steep terrain that may also be dragged by an underlying water flow, i.e., rivers, lakes, oceans, etc., if it exists. The model allows for the seamless simulation of spills that start on land and eventually impact a water body in a single simulation step. The focus here is paid to the integration of the drag shear stresses between the layers, responsible for the oil spreading over a moving water surface. This drag term is solved using a non-iterative implicit method that allows for robust and efficient solutions even with high coupling between both layers. Two synthetic test cases are simulated to demonstrate the accuracy and robustness of the proposed model, obtaining results that validate the model’s behaviour in high-coupling cases. Finally, the spreading hazard for a realistic oil production project is assessed. The results obtained verify the capability of the model to become a useful tool for oil spill forecasting over hybrid terrain–water surfaces.