Oil prices fell on Wednesday after figures from an industry group showed U.S. crude stockpiles rose more than expected last week, reinforcing concerns that the global supply glut in continuing.
U.S. crude futures were down 36 cents at $41.09 a barrel by 11.55 GMT.
Brent crude was 28 cents lower at $41.51, reversing gains in the previous session.
The American Petroleum Institute said U.S. crude stockpiles rose by 8.8 million barrels last week to reach a record high of 531.8 million.
Analysts had expected a stockpile build of 2.7 million barrels.
Official crude inventory data from the U.S. government will be released later on Wednesday.