SAN FRANCISCO (MarketWatch) -- More than three-quarters of of oil production in the Gulf of Mexico has been shut-in due to Gustav, the U.S. Minerals Management Service said in its latest update. Approximately 76.77% of the oil production in the Gulf had been shut-in, according to operator reports as of 12:30 p.m. Eastern Saturday, the MMS reported. The Gulf produces about 1.3 million barrels of oil per day, according to the agency. About 37.16% of natural-gas production is shut-in, it said. Another update was expected at 2 p.m. Eastern.