“The international oil companies are putting in the capital and expertise,” Alex Munton, a Middle East analyst for Wood Mackenzie, a research and consulting firm based in Edinburgh, said. “They need to recover their costs and get a profit margin on top. For it to work, they have to be paid what they are due.

“It would certainly serve Iraq’s interests well to have that contract working smoothly,” he added.

Exxon’s 2009 deal with the Iraqi government to improve production in the West Qurna 1 field was never expected to be lucrative under the best of circumstances. The government had agreed to pay Exxon and its partners $1.90 for each additional barrel of oil they pumped after refurbishing the already producing field. The fees would barely be enough to cover the companies’ costs. Other deals between Iraq and foreign oil companies had similar terms.

International oil contracts are more typically structured to compensate companies with a percentage from sales or a share of production that takes into account the fluctuating price of oil, so that they can be more profitable for the companies when prices rise.

Western oil companies, shut out of Iraq’s oil fields for decades under the government of Saddam Hussein, were willing to do the low-profit, technical service deals to get a foot in the door with the new government that was put in place after the American-led invasion in 2003. Only a few dozen of Iraq’s 80 or so discovered fields are in production, and the government has suggested that it would give more lucrative agreements later to companies that helped the country early on.

For most of the nearly nine-year war, American government advisers aided Iraqi ministries in negotiating and fulfilling contracts. That tapered off as Iraq assumed more sovereignty. President Obama, in a meeting this month with Mr. Maliki in Washington, said Iraq was now a country “sovereign, self-reliant and democratic.”