A Numerical investigation of the sensitivity of the oil weathering process to ambient conditions in accidental ocean oil spills

Abstract

This study focused on developing an improved numerical model to simulate the weathering processes of spilled oil in the sea. The existing models in the literature were extensively studied to establish different empirical and semiempirical formulas to model oil weathering processes such as oil spreading, evaporation, dissolution, and emulsification. Combining the existing models, an oil weathering model was developed. The first-order differential equations were solved by using the Runge-Kutta fourth-order method to obtain an accurate numerical solution. The model results were validated using experimental data available in the literature. The model was then used to study the sensitivity of the oil weathering process to the ambient conditions. The simulation results revealed that the evaporation rate is affected by the sea surface temperature conditions. Also, the time to form the water-in-oil emulsion varies depending on the ambient conditions, where ambient wind speed has a significant impact on the oil emulsification process. During an ocean oil spill, emulsification is one of the critical processes that adversely affects the environment and clean-up procedures due to the formation of water-in-oil emulsion, which changes the oil density and viscosity. Thus, the study is further extended to evaluate the viscosity change of the oil and the factors affecting the oil viscosity.