BAGHDAD , Iraq ( CNN ) -- Iraq awarded a lucrative oil contract to BP and China National Petroleum Corp. , government spokesman Ali al-Dabbagh said Wednesday , while rejecting other companies ' offers for other oil fields . BP and China National Petroleum Corporation have won a lucrative oil contract in Iraq . The joint BP-CNPC bid was for the al-Rumeila oil field , one of the largest in the world . The energy companies are expected to increase production at the oil field by 50 percent , to 285,000 barrels a day , for a service charge of $ 2 for each additional barrel produced , al-Dabbagh said in a statement . The Iraqi government rejected bids for five other oil fields and a natural gas field because the bidders did not agree to the service charge set by the Ministry of Oil , he said . The Ministry of Oil rejected the idea that the failure to award more than one contract made the much-anticipated auction a flop . Iraq did not say how much the BP-CNPC bid was worth . It runs for 20 years . Oil Minister Hussein Shahrastani chaired the government-sponsored auction for the oil and natural gas field contracts Tuesday , after a day 's delay due to a sandstorm . Much of the auction was broadcast live on state television , which Ministry of Oil spokesman Assem Jihad told CNN was a sign of the transparency of the process . He said the government was satisfied with the auction , even though only one contract was awarded , because the contract was for Iraq 's largest oil field . Iraq plans to open bidding this year on 10 more oil fields and one natural gas field , all of which are undeveloped , Jihad said . The companies whose bids were rejected Tuesday have been given time to review their offers , he said . Iraq has some of the largest oil reserves in the world , with an estimated 115 billion barrels -- tying Iran for second place , behind Saudi Arabia 's 264 billion barrels , according to estimates from the Energy Information Administration in the United States . CNN 's Jomana Karadsheh in Baghdad contributed to this report .
Iraq awards lucrative oil contracts to BP , China National Petroleum Corporation . The joint BP - CNPC bid was for the giant al - Rumeila oil field . Energy companies expected to increase production at the field by 50 percent .