The depletion of readily accessible oil reservoirs in conjunction with the demand for fossil fuels leads to the exploration and production of remote deposits, esp. in the deep sea. Operations at hard-to-reach locations far beyond atmospheric conditions are challenging and associated with elevated risk, which became clear when the Deepwater Horizon drilling rig ignited and sank in the Gulf of Mexico in 2010, causing one of the largest oil spills in history with 800,000 m³ of oil spilled at a depth of 1,522 m. The depiction and prediction of the multiphase plume’s behavior under deep-sea conditions and the oil fate is critical for the development of efficient and scientifically sound response strategies, which are key to avert damage to people and the environment. The success of these measures hinges on the accuracy of the models used to simulate the fate of the released oil.
The most crucial input parameters for oil fate modeling are the droplet size distribution (DSD) and the rise behavior of the droplets and bubbles plus physical properties and phase behavior of the substances. These parameters depend on the specific deep-sea conditions (high pressure, low temperature) as well as the blowout conditions and the multiphase character of the highly turbulent oil/gas/water jet exiting the well into the ocean. Thus, blowout and deep-sea conditions must be accounted for when experimental facilities are designed and employed or when oil-spill models are developed and tuned.
New experimental facilities at Hamburg Univ. of Technology enable the discovery of complex processes during blowout and drop rise under deep-sea conditions. A combination of high-speed imaging, particle image velocimetry, and endoscopic technology is used during experiments to make accurate DSD measurements. For the first time, lab and pilot-plant scale jet plants allow generating appropriate predictive correlations between lab-scale and realistic blowout scales. Together with collaborators at the Univ. of W. Australia and Miami, we have developed a new modeling approach for the prediction of the DSD based on the turbulent kinetic energy dissipation rate and a drop-rise model accounting for the specific high-pressure conditions that are corroborated by experimental observations. Here, we present experimental data in conjunction with modeling results.
Pesch, S.; Paris, C. B. B.; Knopf, R.; Maly, M.; Radmehr, A.; Perlin, N.; Vaz, A.; Aman, Z. M.; Hoffmann, M.; Schlüter, M. “Deep-Sea Oil Spills – Investigating Droplet Size Distributions and Oil Fate in Experiments and Modeling”, AGU Fall Meeting Abstracts, vol. 2019, 2019.