Here is the only thing I can find about a Discovery in the Gulf Of Mexico...
http://www.offshore-technology.com/projects/petronius/
"The Petronius field is located in Viosca Knoll, block 786, approximately 130 miles (208km) south-east of New Orleans. It lies in water depths of 1754ft (535m). The field was discovered in 1995 and contains estimated recoverable reserves of 80-100 million barrels of oil equivalent. Petronius has been developed by a compliant tower - the largest free-standing structure in the world. The cost of the project has been put at $500 million. Texaco (the operator) owns 50% of the field and the remaining 50% is owned by Marathon."
The U.S. consumes 19 million barrels a day.
How long would 100 million barrels last?