Preliminary model results for subsurface oil and gas release
Authors: Gronchi Giulia , Pinardi Nadia , Coppini Giovanni , Liubartseva Svitlana , Sepp Neves Augusto 
Published: March 2022

&lt;p&gt;&lt;span&gt;Although most oil spill accidents occur at the sea surface, the growing offshore oil exploration activities increase the likelihood of subsurface releases. In this context, it is necessary to develop a subsurface oil spill model to forecast the oil transport in the water column and to&amp;#160;prepare the response once the oil reaches the coasts and the surface. The novelty is to combine this buoyant plume model with realistic subsurface currents and ocean density fields and compare the results with idealized conditions. &amp;#160;The model will be combined later with a community oil spill model Medslik-II (&lt;/span&gt;&lt;span&gt;http://www.medslik-ii.org&lt;/span&gt;&lt;span&gt;).&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;Following the literature&lt;/span&gt;&lt;span&gt; (&lt;/span&gt;&lt;span&gt;1,2&lt;/span&gt;&lt;span&gt;), a 3D model of a buoyant jet/plume&amp;#160;is developed, which simulates the&amp;#160;key processes in the nearfield approximation. Turbulent entrainment of ambient water (both through forced and shear fluxes), dissolution and turbulent diffusion of oil droplets and gas bubbles&amp;#160;are&amp;#160;realistically represented. The used ambient oceanographic fields are&amp;#160;provided&amp;#160;by&amp;#160;the &lt;/span&gt;&lt;span&gt;Monitoring and Forecasting Centre (MED-MFC) of the &lt;/span&gt;&lt;span&gt;Copernicus Marine Service&lt;/span&gt;&lt;span&gt;. These fields, in particular water density and current velocity, directly control the evolution of the plume in time. In the model, there are options to simulate both oil and oil/gas mixture discharges. Additionally, it is possible to compute instantaneous and continuous subsurface releases.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The model is validated with a unique DeepSpill field experiment conducted in the North Sea with the release of oil and gas&lt;/span&gt;&lt;span&gt; (&lt;/span&gt;&lt;span&gt;3,4,&lt;/span&gt;&lt;span&gt;5&lt;/span&gt;&lt;span&gt;). &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;span&gt;References&lt;/span&gt;&lt;/p&gt;&lt;p&gt;[1] J. H. W. Lee and V. Cheung, Generalized Lagrangian model for buoyant jets in current, Journal of Environmental Engineering, ASCE, 116, (6), 1085-1105, 1990.&lt;/p&gt;&lt;p&gt;&lt;span&gt;[2] P. D. &lt;/span&gt;&lt;span&gt;Yapa and &lt;/span&gt;&lt;span&gt;L. &lt;/span&gt;&lt;span&gt;Zheng, Simulation of oil spills from underwater accidents I: Model development, Journal of Hydraulic Research, 35 (5), 673-688, 1997.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;[3] &lt;/span&gt;&lt;span&gt;P. D. Yapa, L. &lt;/span&gt;&lt;span&gt;Zheng, K. Nakata, Modeling Underwater Oil/Gas Jets and Plumes, &lt;/span&gt;&lt;span&gt;Journal of Hydraulic Engineering,&lt;/span&gt; &lt;span&gt;125, (5), &lt;/span&gt;&lt;span&gt;1999.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;[&lt;/span&gt;&lt;span&gt;4] P. D. Yapa, H. Xie, &lt;/span&gt;&lt;span&gt;Modeling Underwater Oil/Gas Jets and Plumes: Comparison with Field Data&lt;/span&gt;&lt;span&gt;, Journal of Hydraulic Engineering, 128, (9), 2002.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;[&lt;/span&gt;&lt;span&gt;5&lt;/span&gt;&lt;span&gt;] &lt;/span&gt;&lt;span&gt;H. Rye, P. J. Brandvik, T. Str&amp;#248;m, Subsurface blowouts: Results from field experiments, SpillScience and Technology Bulletin, 4, &lt;/span&gt;&lt;span&gt;(&lt;/span&gt;&lt;span&gt;4&lt;/span&gt;&lt;span&gt;)&lt;/span&gt;&lt;span&gt;, 1997.&lt;/span&gt;&lt;/p&gt;