An Iraqi plan to award six no-bid contracts to Western oil companies, which came under sharp criticism from several United States senators this summer, has been withdrawn, participants in the negotiations said on Wednesday.

Iraq’s oil minister, Hussain al-Shahristani, told reporters at an OPEC summit meeting in Vienna on Tuesday that talks with Exxon Mobil, Chevron, Shell, Total, BP and several smaller companies for one-year deals, which were announced in June and subsequently delayed, had dragged on for so long that the companies could not now fulfill the work within that time frame. The companies confirmed on Wednesday that the deals had been canceled.

While not particularly lucrative by industry standards, the contracts were valued for providing a foothold in Iraq at a time when oil companies are being shut out of energy-rich countries around the world. The companies will still be eligible to compete in open bidding in Iraq.

The six no-bid deals were for work to increase Iraqi oil production from existing oil fields by half a million barrels a day  the same amount by which OPEC countries agreed Tuesday to reduce output. After its cancellation of the deals, Iraq reduced by 200,000 barrels per day its goal of producing 2.9 million barrels per day by the end of the year.