Shell said it encountered roughly 150 feet of oil pay in an appraisal well in the Mississippi Canyon block in about 7,257 feet of water.
"We are pleased with the continued success at our Appomattox prospect and this well supports our continuing appraisal efforts to progress this to a new hub class development," David Lawrence, an executive vice president of exploration at Shell, said in a statement.
In 2010, Shell drilled a discovery well in the region that encountered roughly 530 feet of oil pay. A 25,950-foot appraisal sidetrack encountered roughly 380 feet of oil pay.
The deep waters of the Gulf of Mexico are considered one of the most promising resource basins in the world. International explorers say offshore exploration could ease U.S. dependence on foreign oil, though the oil disaster in the gulf in 2010 sparked heightened concern about the safety of deep-water exploration.
The U.S. and Mexican governments this week signed a deal to explore for oil and natural gas along the shared maritime border in the Gulf of Mexico.