China National Petroleum Corp (CNPC), China's largest oil and gas producer, and Britain's oil giant BP signed an initial agreement on Thursday with Iraq's Oil Ministry to develop Rumaila, Iraq's largest oilfield, China Daily reported Saturday. The signed contract will be referred to the cabinet for approval, the newspaper said, citing Iraq's Oil Ministry spokesman Asim Jihad. The newspaper said the deal requires an investment of more than 15 billion U.S. dollars. A BP spokesman confirmed that they had signed the initial contract and were waiting approval from the Iraqi government. He said it was an important milestone and BP hoped to be able to sign the final agreement before the end of this year. CNPC said it was not ready to comment. BP and CNPC won the Rumaila deal after they cut their proposed remuneration fee to 2 U.S. dollars per barrel. Iraq offered eight contracts in a June auction. As Iraq's largest producing oilfield, Rumaila accounted for almost half of the country's total output of 2.4 million barrels per day (BPD), with a current capacity of 1.1 million BPD. The field's reserves are estimated to be 17 billion barrels. BP and CNPC aim to boost its output to 2.85 million barrels per day over the 20-year contract. Under the service contract, BP holds a 38-percent stake in the Rumaila venture, while CNPC has a 37-percent share. Iraq's State Oil Marketing Organization holds the rest. The contract for Rumaila aims to inject foreign cash to overhaul dilapidated facilities and outdated practices. 