Iraq is expected to sign Saturday an agreement with four international oil companies to build a multi-billion-dollar oil field water injection plant, a senior Iraqi oil official said Monday.

Abdul Mahdy al-Ameedi, head of the Oil Ministry's Petroleum Contracts and Licensing Directorate, said U.K. super major BP PLC (BP), U.S. giant Exxon Mobil Corp. (XOM), Italy's Eni SpA (E) and Russia's OAO Lukoil Holdings (LKOH.RS) have agreed to build the first phase of the project, which is designed to produce some 4.2 million barrels a day of seawater to be injected into Iraqi oil fields in order to boost production.

"The development agreement of the project is planned to be signed Nov. 26 in
Turkey ," Ameedi told Dow Jones Newswires in an exclusive interview in Baghdad .

Ameedi declined to give costs of the project but Iraqi oil officials had previously said that foreign companies had suggested the cost could be more than $3 billion.

Exxon Mobil was picked as operator of the project, Ameedi said.