Crude inventories in the United States rose by 5.3 million barrels in the week to Nov. 11, compared with expectations for an increase of 1.5 million barrels.

The climb in inventories was mainly due to higher importsthat averaged 910,000 barrels per day (bpd), according to data released by the U.S. Energy Information Administration on Wednesday.

U.S. benchmark WTI crude CLc1 was down 11 cents, or 0.24 percent, at $45.46 a barrel at 0040 GMT. European ICE Brent LCOc1 crude futures fell 16 cents, or 0.34 percent, to $46.47 per barrel.

"Crude oil struggled to keep its head above water after the weekly EIA showed another large rise in inventories ... Stocks of crude oil jumped 5.27 million barrels, much more than expected," Australian bank ANZ said in a note.

Refining margins in all five U.S. regional petroleum districts fell in the week ended Nov. 11, Credit Suisse said in a weekly report on Wednesday.

"The U.S. EIA produced a higher than expected crude inventory figure, but this was subsumed into OPEC gossip," said OANDA senior market analyst Jeffrey Halley. "We are well into headline trading season as Nov. 30 approaches."

OPEC countries are ready to reach a "forceful" agreement on cutting oil output, Venezuelan President Nicolas Maduro said on Wednesday, following a meeting with OPEC Secretary-General Mohammed Barkindo in Caracas. OPEC members are due to meet on Nov. 30.

Russia has also expressed willingness to support an OPEC decision to freeze oil output, Russian Energy Minister Alexander Novak said on Wednesday, adding that he may meet Saudi Arabia's Energy Minister Khalid al-Falih at a gas conference in Doha this week.