Multimedia fate modeling of oil spills in ice-infested waters: an exploration of the feasibility of fugacity-based approach

The increasing demand for energy and the high probability of finding vast reserves have shifted offshore exploration and production activity into colder and harsher environments. Offshore activity increases risk of oil spills in these colder and harsher marine environments. The unique features of such environments make oil spills more challenging. The development of a coastal oil spill contingency plan requires the prediction of fate and transport of oil. However, there is limited work on the modeling approaches for the prediction of multimedia fate of oil spilled on ice and colder waters. This paper proposes a framework that combines surface oil weathering algorithms with Level IV fugacity models for modeling the fate and transport of oil spilled in Arctic like marine environments. Four bulk compartments were used for modeling: air, ice cover, water and sediment. Weathering of surface oil on and under the ice cover is represented by a system of differential equations. Unsteady state mass balance equations are also developed for each of the four bulk phases. The fourth-order Runge-Kutta method is employed to solve the combination of two sets of differential equations. The outputs of the multimedia fate model are time-dependent profiles of oil slick area, fraction evaporated, water content in oil, viscosity, and concentration of oil in air, ice cover, water, and sediment. The application of the proposed approach is illustrated through the simulation of a hypothetical oil spill in the Labrador Sea.