A technique to track and forecast ocean eddies spun off by the North Brazil Current was set up by Fugro Geos of Houston, after a drillship working off Trinidad-Tobago was forced to shut down subsea operations several times. Anticipation of the approaching eddies allows for better planning of subsea operations, according to a Fugro Geos statement.
The North Brazil Current moves up the coast of South America, and can generate speeds up to three knots. The eddies spun off affected the drillship Jack Ryan, working for Exxon Mobil off Trinidad.
Fugro Geos said that previously an ADCP unit (acoustic doppler current profiler) was mounted on the drillship to monitor nearby currents. To better predict developing eddies, the contractor deployed a 300 KHz ADCP within a Endeco/YSI V-fin towfish, pulled behind the stern of a vessel of opportunity.
The system profiles currents up to 80 meters below the towfish. Data is sent back to the surface, corrected by GPS data to account for the velocity of tow and ship motion, displayed, and plotted.
Fugro Geos has developed a Trinidad Ring Advisory Cooperative to plot and forcast eddy movement based on drifter tracks and satellite data. Part of the plan is to tow an ADCP in order to better define the edge of the ring and its speed. From the data, statistics on the formation of rings, their size, intensity and path can be predicted for Trinidad, Venezuela, and Barbados concessions.