Oil prices declined on Tuesday with the return of more and more production facilities to operation in the U.S. Gulf. Meanwhile, the Chinese data diminished the outlook of crude demand. Brent slipped by 0.2%, to $66.38 a barrel. WTI dropped by 0.2% and was traded at $59.48 a barrel. However, it might take several days for the production to resume fully after a storm leaves the Gulf of Mexico.