Crude oil inventories in the United States increased by 4.9 million barrels during the week ending July 17, according to data by the US Energy Information Administration (EIA) on Wednesday.
A decline between 575,000 and 1.9 million barrels was expected by market experts and surveys.
On Tuesday, data by the American Petroleum Institute (API) suggested an increase of 7.5 million barrels in the US oil stocks.
Meanwhile, distillate stockpiles increased by 1.1 million barrels last week.
Oil prices declined following the release of the data.
Brent crude futures are down by 1.35%, while WTI futures are now trading lower by 1.29%