A major operator in Brazil successfully deployed the large-hole version of the 3-D radial probe to determine the oil/water contact in a 12 1/4-in. deepwater well in a presalt carbonate formation. The probe can sample and take pressure tests quickly with minimal drawdown on the reservoir over a total surface flow area of nearly 80 sq. in., expanding the operational envelope of formation testing more than 40 times over the largest conventional probe.