Simulation of Hydraulic Dispersion of Oil by A Water Jet (Subsurface Mechanical Dispersion, SSMD)

Subsurface mechanical dispersion (SSMD) has been proposed as an alternative measure for dispersant to break up oil emanating from underwater blowouts. The idea is to inject water horizontally into vertical oil jets causing the jet to break into small oil droplets precluding the usage of chemical dispersant. Using the Reynolds-averaged Navier–Stokes equations (RANS equations) within the computational fluid dynamic (CFD) model Fluent, we conducted a numerical simulation of an oil plume emanating from a riser of diameter 0.50 m (18.75 inches), and the water jet was from a 0.05 m diameter pipe at 5.0 m above the oil orifice. The oil speed was around 1.0 m/s while that of water was around 26 m/s. We found that SSMD treatment enhanced the dilution of the oil in the volume by comparison to an oil-only plume suggesting an enhanced breakup of the oil. The maximum stable diameter was also computed, and it was found that it was 40% smaller for SSMD by comparison to the oil only. Additional investigations (experiments and detailed simulations) are needed to address the effectiveness of SSMD.