Behavior of Oil and Gas from Deepwater Blowouts

Abstract

This paper presents a detailed analysis of different deepwater blowout scenarios using the Clarkson deepwater oil and gas model (CDOG). In CDOG, hydrate formation, hydrate decomposition, gas dissolution, nonideal behavior of gas, and possible gas separation from the main plume due to strong cross-currents, are integrated with the jet/plume hydrodynamics and thermodynamics. CDOG takes into account unsteady-state three-dimensional variation of ambient currents and density stratification. Detailed comparisons between CDOG simulations and deepspill field experiments have been published. The model is used to simulate 30 deepwater blowout scenarios based on realistic cases and the results are analyzed in this paper. The scenarios demonstrate the differences in plume behavior due to different ambient conditions, different types of gas, possible hydrate formation, and variations in gas-to-oil ratio. Some key findings of these analyses follow. Oil droplet sizes affect the oil surfacing time significantly. For oil-only blowouts, the ambient conditions do not affect the oil surfacing time significantly, but the location and the size of the slick are affected. For oil and gas mixes, the surfacing time is not sensitive to the type of gas in the mix, but is somewhat dependent on the ambient conditions. In none of the cases simulated here, did free gas reach the water surface. While changing the release temperature had only an insignificant effect on the model results, changing oil type or gas-to-oil ratio did affect the model results. The analyses are useful to engineers/scientists and administrators.