China's independent oil companies are ramping up operations in Iraq, investing billions of dollars in OPEC's number two producer even as some global majors have scaled back from a market dominated by Beijing's big state-run firms.

Drawn by more lucrative contract arrangements, smaller Chinese producers are on track to double their output in Iraq to 500,000 barrels per day by around 2030, according to estimates by executives at four of the firms.

For Baghdad, which is also seeking to lure global giants, the growing presence of the mostly privately run Chinese players marks a shift as Iraq comes under growing pressure to accelerate projects, according to multiple Iraqi energy officials. In recent years, Iraq's oil ministry had pushed back on rising Chinese control over its oilfields.