Oil prices lost Friday amid growing supplies from Organization of Petroleum Exporting Countries (OPEC) and Russia.
Iraqi Oil Ministry spokesman Asim Jihad said the country exported 2.94 million barrels a day in December, the highest number since the 1980s.
OPEC decided to maintain its collective output quota at 30 million barrels a day at the Nov. 27 meeting in Vienna.
There was no sign that producers would cut production in response to the slump. OPEC's production dropped 122,000 barrels a day from November to 30.24 million in December, a Bloomberg survey indicated.
Russian oil output rose 0.3 percent in December to a record of 10.667 million barrels a day, according to the data from the Energy Ministry.
Russian Energy Minister Alexander Novak said last month that crude output from Russia, the world's largest crude producer, will be close to the 2014 level of 10.6 million barrels a day in 2015.
Stockpiles at Cushing, the delivery point for U.S. crude futures gained 2 million barrels to 30.8 million barrels in the week ending Dec. 26, according to the Energy Information Administration (EIA).