The Russian oil concession in Iraq shows how geopolitics shaped the awarding of the primary contracts but is not preventing U.S. oil services companies from winning business today, helping their profits and stock prices.

Lukoil struggled to hold onto its Saddam Hussein-era contract in a sprawling, geopolitical chess game over a decade. It wrapped in U.S. oil companies, the Russian government, and threats by Moscow to cancel post-War Iraqi debt relief if the Iraqis followed U.S. advice and stripped Lukoil of its license.

But when Lukoil finally secured rights to the field by re-bidding for it, the company quickly subcontracted the drilling. A U.S. oil-services company, which Lukoil executives said they could not specify to comply with securities legislation, won the first contract for three exploration wells.

The more sweeping drilling tendering for this field, called West Qurna 2, is just getting under way now. Under its contract, Lukoil committed to produce 1.8 million barrels of oil per day from the field by 2017; it was unclear whether that would be revised along with the broader revision of output targets under way in Iraq now.

In any case, Lukoil says it will need to drill more than 500 wells to develop the deposit, which is underneath agricultural, scrub and dry clay land west of the Euphrates River in the southern Basra province. Along with the contract already granted, Lukoil has tendered for 23 production wells, and plans another tender this year for another 50 or so. Analysts estimate drilling an oil well in Iraq costs between $10 and $20 million.

Mr. Munton of Wood Mackenzie said U.S. oil-services companies were poised to win much of the drilling work at West Qurna, as at other Iraqi fields, though other capital outlays such as for processing facilities and pipelines would go to a more international cast.

Joost R. Hiltermann, deputy program director for the Middle East and North Africa with the International Crisis Group, which is monitoring the security implications of Iraq’s oil policies, said Iraqi officials are unlikely to try to diversify away from U.S. companies at the less politically sensitive subcontracting level.