Marvin Odum, upstream director for Shell operations in the Americas, said the estimate bodes well for energy supplies for the United States.
"It will also secure employment for more offshore workers," he added.
Cardamom is expected to reach an eventual peak production rate of 50,000 barrels of oil equivalent per day. More than 140 million boe is expected from the project over its lifetime.
Shell's announcement follows similar declarations from Exxon Mobil, which announced discoveries while drilling in 7,000 feet of water south of Louisiana that have a recoverable resource potential of more than 700 million barrels of oil equivalent.
"This is one of the largest discoveries in the Gulf of Mexico in the last decade," the company said.
Deep-water exploration is under scrutiny following last year's oil disaster in the gulf. Republican lawmakers pushing for more access to domestic reserves praised the latest finds, however.
"The prospect of new American-made energy supplies means less pain at the pump for American families and more American jobs," U.S. Rep. Fred Upton, R-Mich., chairman of the House Energy and Commerce Committee, said in a statement.
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