Exxon and Statoil announced the start of development of the Julia oil field in the Gulf of Mexico. Cost of the project is estimated at more than $4 billion. The field, discovered in 2007, could hold as much as 6 billion barrels of reserves.
President of Exxon Mobil Development Co. Neil Duffin said the field is more than 5 miles beneath the ocean's surface.
"Julia is one of the first large oil discoveries in the ultra-deep-water frontier of the Gulf of Mexico," he said in a statement.
Statoil said the lifetime of the frontier field is estimated at up to 40 years. Initial production, expected to begin in 2016, should be around 34,000 barrels of oil per day.
Exploration in the deep waters of the Gulf of Mexico has sparked safety concerns in the wake of the Deepwater Horizon spill in 2010. Last month, the U.S. government conducted a test of a special capping system designed to respond to deep-water incidents.
"Enhanced technologies will be deployed to ensure the safe and environmentally responsible development of this important energy resource," Duffin said.