Combined releases of oil and gas under pressure; the influence of live oil and natural gas on initial oil droplet formation

Abstract

Both oil droplets and gas bubbles have simultaneously been quantified in laboratory experiments that simulate deep-water subsea releases of both live oil (saturated with gas) and additional natural gas under high pressure. These data have been used to calculate particle size distributions (50–5000 μm) for both oil and gas. The experiments showed no significant difference in oil droplet sizes versus pressure (from 5 m to 1750 m) for experiments with live oil. For combined releases of live oil and natural gas, oil droplet sizes showed a clear reduction as a function of increased gas void fraction (increased release velocity) and a weak reduction with increased depth (increased gas density/momentum). Oil droplets were reduced by a factor of 3 to 4 during simulated subsea dispersant injection (SSDI) and no significant effect of pressure was observed. This indicates that SSDI effectiveness is not dependent on water depth or pressure.