Brent crude futures, the international benchmark for oil prices, were at $51.01 per barrel at 00:23 GMT, up 21 cents, or 0.4 percent, from their last close, as reported by Reuters.
U.S. West Texas Intermediate (WTI) crude futures were at $47.70 a barrel, up 15 cents, or 0.3 percent.
U.S. crude inventories fell by 9.2 million barrels in the week to Aug. 11 to 469.2 million, industry group the American Petroleum Institute said on Tuesday.
Read alsoOil prices dip on weak Chinese refining activity – ReutersThat compared with analyst expectations for a decrease of 3.1 million barrels.
However, gasoline stocks climbed by 301,000 barrels, compared with analyst expectations in a Reuters poll for a 1.1 million barrel decline.
Official Energy Information Administration (EIA) data will be published late on Wednesday.
More broadly, analysts said oil markets were still being weighed down, preventing them moving much higher than current levels.