The CEO of Italian oil and gas company Eni, Paolo Scaroni, said he expects the consortium led by Eni to invest $18 billion in the Zubair oilfield.
He added that the group, which includes Occidental Petroleum Corp and South Korea's KOGAS, has already invested 4-5 billion euros in the project.
Production at the field is currently running at around 270,000 bpd.
But speaking at an International Energy Agency conference in Rome, Scaroni said: "Our adrenaline rush now is not what it was when we entered Iraq … [it's] more complex than we first thought."
Issues with Iraq included bureaucracy, limited energy infrastructure, and the political situation with the Kurdistan region following its own policy when it comes to hydrocarbon activities. The government in Baghdad should consider why some global companies are going to Kurdistan, he added.
Scaroni also confirmed that Eni did not intend to invest in Kurdistan.