The American Petroleum Institute (API) on Tuesday reported an increase of 1.586 million barrels of crude oil in U.S. inventories for the week ending Sept. 22.
Analysts expected a drop of 1.650 million barrels for this week.
The API reported a decline of 5.250 million barrels in the previous week.
Oil prices climbed on Tuesday.
The West Texas Intermediate for November delivery added 71 cents, or 0.79 percent, to settle at 90.39 U.S. dollars a barrel on the New York Mercantile Exchange.