A model to simulate the spreading of oil and gas in underwater oil spills

摘要

The rapid growth of offshore oil production and undersea oil delivery pipelines increases the risk ofudunderwater oil spill. In this study, a model based on the Lagrangian particle tracking method is developed to simulateudthe spreading of oil and gas in an underwater oil spill, which is helpful to estimate the environmental impact and to findudeffective measures for preventing the spreading of oil. The oil droplets and gas bubbles released from the leakage pointudare modeled by a large number of representative particles, which are divided into several groups to simulate differentudcomponents of oil and gas leaked from the underwater blowout. The movement of each particle in one time stepudincludes two components, a mean movement and a random walk. The mean movement is computed by combining theudeffect of surrounding marine hydrodynamic, the buoyant jet flow near the leakage point and the rise velocity ofudrepresentative oil droplets or gas bubbles.The random walk method is used to simulate the turbulent diffusion. Theudcompressibility and dissolution of gas are also considered, which play an important role in deepwater. Comparing withudthe previous models for underwater oil spill based on the integral Lagrangian control volume method, the present modeludis more flexible in simulating the crude oil which has complex components. The model is validated by severaludexperiment cases and successfully applied to simulate the DeepSpill field expreiment, and good agreement between theudcalculation and the observation is obtained. The fractionation of different gas bubbles or oil droplets is considered andudsignificant differences in the underwater distribution of oil droplets and gas bubbles with different sizes are clearlyudshown in the simulated results.