Oil was sharply down Wednesday at five-week lows on expectations of a build-up in official U.S. crude stocks.
U.S. crude was down 79 cents, or 1.69%, at $45.88 at 07:00 ET, while Brent crude lost 1.66% to $47.34.
American Petroleum Institute (API) figures Tuesday showed a jump of 9.3 million barrels in U.S. crude inventories.
Official weekly stockpile figures from the Energy Information Administration (EIA) are due for release later in the session.
The EIA is expected to report a rise of one million barrels in U.S. crude stocks.
Doubts remain about OPEC’s ability to deliver a planned cut in output to 32-5-33 million barrels a day to address a global supply glut.
OPEC is due to hold a formal meeting in Vienna on November 30.
The dollar was lower. A weaker dollar underpins demand for oil.