Oil traded lower as the U.S. crude oil inventories data still weighed on oil prices. U.S. crude inventories increased by 2.62 million barrels to 456.2 million in the week to August 14.

Analysts had expected U.S. crude oil inventories to decline by 0.6 million barrels.

Crude stocks at the Cushing, Oklahoma, rose by 326,000 barrels.

This data added to concerns over the global oil supply.

The EIA downgraded its crude oil price forecasts. It expects West Texas Intermediate to be $49 per barrel in 2015, $6 lower than the previous estimate, and $54 per barrel in 2016, $8 per barrel lower than the previous estimate.

Concerns over a slowdown in the Chinese economy also weighed on oil prices.

WTI crude oil for September delivery traded in the range between $40.21 and $41.22 a barrel on the New York Mercantile Exchange.

Brent crude oil for October decreased to $46.71 a barrel on ICE Futures Europe.